Changes in nitrogen isotope ratios in estuarine biota following nutrient reductions to Narragansett Bay

EPA Science Inventory

Increased nutrient inputs globally have resulted in widespread eutrophication to many coastal water bodies including Narragansett Bay. Efforts to reduce point source nitrogen load¬ings from waste water treatment facilities (WWTFs) and combined sewer overflows (CSOs) started i...

Nutrient and sediment concentrations, yields, and loads in impaired streams and rivers in the Taunton River Basin, Massachusetts, 1997-2008

USGS Publications Warehouse

Barbaro, Jeffrey R.; Sorenson, Jason R.

2013-01-01

Rapid development, population growth, and the changes in land and water use accompanying development are placing increasing stress on water resources in the Taunton River Basin. An assessment by the Massachusetts Department of Environmental Protection determined that a number of tributary streams to the Taunton River are impaired for a variety of beneficial uses because of nutrient enrichment. Most of the impaired reaches are in the Matfield River drainage area in the vicinity of the City of Brockton. In addition to impairments of stream reaches in the basin, discharge of nutrient-rich water from the Taunton River contributes to eutrophication of Mount Hope and Narragansett Bays. To assess water quality and loading in the impaired tributary stream reaches in the basin, the U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection compiled existing water-quality data from previous studies for the period 1997-2006, developed and calibrated a Hydrological Simulation Program-FORTRAN (HSPF) precipitation-runoff model to simulate streamflow in areas of the basin that contain the impaired reaches for the same time period, and collected additional streamflow and water-quality data from sites on the Matfield and Taunton Rivers in 2008. A majority of the waterquality samples used in the study were collected between 1999 and 2006. Overall, the concentration, yield, and load data presented in this report represent water-quality conditions in the basin for the period 1997-2008. Water-quality data from 52 unique sites were used in the study. Most of the samples from previous studies were collected between June and September under dry weather conditions. Simulated or measured daily mean streamflow and water-quality data were used to estimate constituent yields and loads in the impaired tributary stream reaches and the main stem of the Taunton River and to develop yield-duration plots for reaches with sufficient water-quality data. Total phosphorus concentrations in the impaired-reach areas ranged from 0.0046 to 0.91 milligrams per liter (mg/L) in individual samples (number of samples (n)=331), with a median of 0.090 mg/L; total nitrogen concentrations ranged from 0.34 to 14 mg/L in individual samples (n=139), with a median of 1.35 mg/L; and total suspended solids concentrations ranged from 2/d) for total phosphorus and 100 lb/mi2/d for total nitrogen in these reaches. In most of the impaired reaches not affected by the Brockton Advanced Water Reclamation Facility outfall, yields were lower than in reaches downstream from the outfall, and the difference between measured and threshold yields was fairly uniform over a wide range of flows, suggesting that multiple processes contribute to nonpoint loading in these reaches. The Northeast and Mid-Atlantic SPAtially-Referenced Regression On Watershed (SPARROW) models for total phosphorus and total nitrogen also were used to estimate annual nutrient loads in the impaired tributary stream reaches and main stem of the Taunton River and predict the distribution of these loads among point and diffuse sources in reach drainage areas. SPARROW is a regional, statistical model that relates nutrient loads in streams to upstream sources and land-use characteristics and can be used to make predictions for streams that do not have nutrient-load data. The model predicts mean annual loads based on longterm streamflow and water-quality data and nutrient source conditions for the year 2002. Predicted mean annual nutrient loads from the SPARROW models were consistent with the measured yield and load data from sampling sites in the basin. For conditions in 2002, the Brockton Advanced Water Reclamation Facility outfall accounted for over 75 percent of the total nitrogen load and over 93 percent of the total phosphorus load in the Salisbury Plain and Matfield Rivers downstream from the outfall. Municipal point sources also accounted for most of the load in the main stem of the Taunton River. Multiple municipal wastewater discharges in the basin accounted for about 76 and 46 percent of the delivered loads of total phosphorus and total nitrogen, respectively, to Mount Hope Bay. For similarly sized watersheds, total delivered loads were lower in watersheds without point sources compared to those with point sources, and sources associated with developed land accounted for most of the delivered phosphorus and nitrogen loads to the impaired reaches. The concentration, yield, and load data evaluated in this study may not be representative of current (2012) point-source loading in the basin; in particular, most of the water-quality data used in the study (1999-2006) were collected prior to completion of upgrades to the Brockton Advanced Water Reclamation Facility that reduced total phosphorus and nitrogen concentrations in treated effluent. Effluent concentration data indicate that, for a given flow rate, effluent loads of total phosphorus and total nitrogen declined by about 80 and 30 percent, respectively, between the late 1990s and 2008 in response to plant upgrades. Consequently, current (2012) water-quality conditions in the impaired reaches downstream from the facility likely have improved compared to conditions described in the report.

A Bayesian changepoint-threshold model to examine the effect of TMDL implementation on the flow-nitrogen concentration relationship in the Neuse River basin.

PubMed

Alameddine, Ibrahim; Qian, Song S; Reckhow, Kenneth H

2011-01-01

In-stream nutrient concentrations are well known to exhibit a strong relationship with river flow. The use of flow measurements to predict nutrient concentrations and subsequently nutrient loads is common in water quality modeling. Nevertheless, most adopted models assume that the relationship between flow and concentration is fixed across time as well as across different flow regimes. In this study, we developed a Bayesian changepoint-threshold model that relaxes these constraints and allows for the identification and quantification of any changes in the underlying flow-concentration relationship across time. The results from our study support the occurrence of a changepoint in time around the year 1999, which coincided with the period of implementing nitrogen control measures as part of the TMDL program developed for the Neuse Estuary in North Carolina. The occurrence of the changepoint challenges the underlying assumption of temporal invariance in the flow-concentrations relationship. The model results also point towards a transition in the river nitrogen delivery system from a point source dominated loading system towards a more complicated nonlinear system, where non-point source nutrient delivery plays a major role. Moreover, we use the developed model to assess the effectiveness of the nitrogen reduction measures in achieving a 30% drop in loading. The results indicate that while there is a strong evidence of a load reduction, there still remains a high level of uncertainty associated with the mean nitrogen load reduction. We show that the level of uncertainty around the estimated load reduction is not random but is flow related. Copyright © 2010 Elsevier Ltd. All rights reserved.

Factors affecting nutrient trends in major rivers of the Chesapeake Bay Watershed

USGS Publications Warehouse

Sprague, Lori A.; Langland, M.J.; Yochum, S.E.; Edwards, R.E.; Blomquist, J.D.; Phillips, S.W.; Shenk, G.W.; Preston, S.D.

2000-01-01

Trends in nutrient loads and flow-adjusted concentrations in the major rivers entering Chesapeake Bay were computed on the basis of water-quality data collected between 1985 and 1998 at 29 monitoring stations in the Susquehanna, Potomac, James, Rappahannock, York, Patuxent, and Choptank River Basins. Two computer models?the Chesapeake Bay Watershed Model (WSM) and the U.S. Geological Survey?s 'Spatially Referenced Regressions on Watershed attributes' (SPARROW) Model?were used to help explain the major factors affecting the trends. Results from WSM simulations provided information on temporal changes in contributions from major nutrient sources, and results from SPARROW model simulations provided spatial detail on the distribution of nutrient yields in these basins. Additional data on nutrient sources, basin characteristics, implementation of management practices, and ground-water inputs to surface water were analyzed to help explain the trends. The major factors affecting the trends were changes in nutrient sources and natural variations in streamflow. The dominant source of nitrogen and phosphorus from 1985 to 1998 in six of the seven tributary basins to Chesapeake Bay was determined to be agriculture. Because of the predominance of agricultural inputs, changes in agricultural nutrient sources such as manure and fertilizer, combined with decreases in agricultural acreage and implementation of best management practices (BMPs), had the greatest impact on the trends in flow-adjusted nutrient concentrations. Urban acreage and population, however, were noted to be increasing throughout the Chesapeake Bay Watershed, and as a result, delivered loads of nutrients from urban areas increased during the study period. Overall, agricultural nutrient management, in combination with load decreases from point sources due to facility upgrades and the phosphate detergent ban, led to downward trends in flow-adjusted nutrient concentrations atmany of the monitoring stations in the watershed. The loads of nutrients, however, were not reduced significantly at most of the monitoring stations. This is due primarily to higher streamflow in the latter years of the monitoring period, which led to higher loading in those years.Results of this study indicate a need for more detailed information on BMP effectiveness under a full range of hydrologic conditions and in different areas of the watershed; an internally consistent fertilizer data set; greater consideration of the effects of watershed processes on nutrient transport; a refinement of current modeling efforts; and an expansion of the non-tidal monitoring network in the Chesapeake Bay Watershed.

Chesapeake Bay Tributary Strategies

EPA Pesticide Factsheets

Chesapeake Bay Tributary Strategies were developed by the seven watershed jurisdictions and outlined the river basin-specific implementation activities to reduce nutrient and sediment pollutant loads from point and nonpoint sources.

Sources and loads of nutrients in the South Platte River, Colorado and Nebraska, 1994-95

USGS Publications Warehouse

Litke, D.W.

1996-01-01

The South Platte River Basin was one of 20 river basins selected in 1991 for investigation as part of the U.S. Geological Survey's National Water- Quality Assessment (NAWQA) Program. Nationwide, nutrients have been identified as one of the primary nationwide water-quality concerns and are of particular interest in the South Platte River Basin where nutrient concentrations are large compared to concentrations in other NAWQA river basins. This report presents estimates of the magnitude of nutrient-source inputs to the South Platte River Basin, describes nutrient concen- trations and loads in the South Platte River during different seasons, and presents comparisons of nutrient inputs to instream nutrient loads. Annual nutrient inputs to the basin were estimated to be 306,000 tons of nitrogen and 41,000 tons of phosphorus. The principal nutrient sources were wastewater-treatment plants, fertilizer and manure applications, and atmospheric deposition. To characterize nutrient concentrations and loads in the South Platte River during different seasons, five nutrient synoptic samplings were conducted during 1994 and 1995. Upstream from Denver, Colorado, during April 1994 and January 1995, total nitrogen concentrations were less than 2 milligrams per liter (mg/L), and total phosphorus concentrations were less than 0.2 mg/L. The water in the river at this point was derived mostly from forested land in the mountains west of Denver. Total nutrient concentrations increased through the Denver metropolitan area, and concentration peaks occurred just downstream from each of Denver's largest wastewater-treatment plants with maximum concentrations of 13.6 mg/L total nitrogen and 2.4 mg/L total phosphorus. Nutrient concen- concentrations generally decreased downstream from Denver. Upstream from Denver during April 1994 and January 1995, total nitrogen loads were less than 1,000 pounds per day (lb/d), and total phosphorus loads were less than 125 lb/d. Total nutrient loads increased through the Denver metropolitan area, and load peaks occurred just downstream from each of Denver's largest wastewater-treatment plants, with a maximum load of 14,000 lb/d total nitrogen and 2,300 lb/d total phosphorus. In April 1994, nutrient loads generally decreased from Henderson, Colorado, to North Platte, Nebraska. In January 1995, however, nutrient loads increased from Henderson to Kersey, Colorado (maximum loads of 31,000 lb/d total nitrogen and 3,000 lb/d total phosphorus), and then decreased from Kersey to North Platte. Seasonal nutrient loads primarily were dependent on streamflow. Total nitrogen loads were largest in June 1994 and January 1995 when streamflows also were largest. During June, streamflow was large, but nitrogen concentrations were small, which indicated that snowmelt runoff diluted the available supply of nitrogen. Total phosphorus loads were largest in June, when streamflow and phosphorus concentrations were large, which indicated an additional source of phosphorus during snowmelt runoff. Streamflow along the South Platte River was smallest in April and August 1994, and nutrient loads also were smallest during these months. The downstream pattern for nutrient loads did not vary much by season. Loads were large at Henderson, decreased between Henderson and Kersey, and usually were largest at Kersey. The magnitude of the decrease in loads between Henderson and Kersey varied between synoptics and was dependent on the amount of water removed by irrigation ditches. Nutrient loads leaving the basin were very small compared to the estimated total nutrient inputs to the basin. Streamflow balances indicated that the South Platte River is a gaining river throughout much of its length; streamflow-balance residuals were as large as 15 cubic feet per second per mile. Nutrient-load balances indicated that increases in river nitrate loads were, in some places, due to nitrification and, elsewhere, were due to the influx of nitrate-enriched ground water to

Selected nutrients and pesticides in streams of the eastern Iowa basins, 1970-95

USGS Publications Warehouse

Schnoebelen, Douglas J.; Becher, Kent D.; Bobier, Matthew W.; Wilton, Thomas

1999-01-01

 The statistical analysis of the nutrient data typically indicated a strong positive correlation of nitrate with streamflow. Total phosphorus concentrations with streamflow showed greater variability than nitrate, perhaps reflecting the greater potential of transport of phosphorus on sediment rather than in the dissolved phase as with nitrate. Ammonia and ammonia plus organic nitrogen showed no correlation with streamflow or a weak positive correlation. Seasonal variations and the relations of nutrients and pesticides to streamflow generally corresponded with nonpoint‑source loadings, although possible point sources for nutrients were indicated by the data at selected monitoring sites. Statistical trend tests for concentrations and loads were computed for nitrate, ammonia, and total phosphorus. Trend analysis indicated decreases for ammonia and total phosphorus concentrations at several sites and increases for nitrate concentrations at other sites in the study unit.

Spatial optimization of watershed management practices for nitrogen load reduction using a modeling-optimization framework

EPA Science Inventory

Best management practices (BMPs) are perceived as being effective in reducing nutrient loads transported from non-point sources (NPS) to receiving water bodies. The objective of this study was to develop a modeling-optimization framework that can be used by watershed management p...

Impact of Climate Variability and Landscape Patterns on Water Budget and Nutrient Loads in a Peri-urban Watershed: A Coupled Analysis Using Process-based Hydrological Model and Landscape Indices.

PubMed

Li, Chongwei; Zhang, Yajuan; Kharel, Gehendra; Zou, Chris B

2018-06-01

Nutrient discharge into peri-urban streams and reservoirs constitutes a significant pressure on environmental management, but quantitative assessment of non-point source pollution under climate variability in fast changing peri-urban watersheds is challenging. Soil and Water Assessment Tool (SWAT) was used to simulate water budget and nutrient loads for landscape patterns representing a 30-year progression of urbanization in a peri-urban watershed near Tianjin metropolis, China. A suite of landscape pattern indices was related to nitrogen (N) and phosphorous (P) loads under dry and wet climate using CANOCO redundancy analysis. The calibrated SWAT model was adequate to simulate runoff and nutrient loads for this peri-urban watershed, with Nash-Sutcliffe coefficient (NSE) and coefficient of determination (R 2 ) > 0.70 and percentage bias (PBIAS) between -7 and +18 for calibration and validation periods. With the progression of urbanization, forest remained the main "sink" landscape while cultivated and urban lands remained the main "source" landscapes with the role of orchard and grassland being uncertain and changing with time. Compared to 1984, the landscape use pattern in 2013 increased nutrient discharge by 10%. Nutrient loads modelled under wet climate were 3-4 times higher than that under dry climate for the same landscape pattern. Results indicate that climate change could impose a far greater impact on runoff and nutrient discharge in a peri-urban watershed than landscape pattern change.

Impact of Climate Variability and Landscape Patterns on Water Budget and Nutrient Loads in a Peri-urban Watershed: A Coupled Analysis Using Process-based Hydrological Model and Landscape Indices

NASA Astrophysics Data System (ADS)

Li, Chongwei; Zhang, Yajuan; Kharel, Gehendra; Zou, Chris B.

2018-06-01

Nutrient discharge into peri-urban streams and reservoirs constitutes a significant pressure on environmental management, but quantitative assessment of non-point source pollution under climate variability in fast changing peri-urban watersheds is challenging. Soil and Water Assessment Tool (SWAT) was used to simulate water budget and nutrient loads for landscape patterns representing a 30-year progression of urbanization in a peri-urban watershed near Tianjin metropolis, China. A suite of landscape pattern indices was related to nitrogen (N) and phosphorous (P) loads under dry and wet climate using CANOCO redundancy analysis. The calibrated SWAT model was adequate to simulate runoff and nutrient loads for this peri-urban watershed, with Nash-Sutcliffe coefficient (NSE) and coefficient of determination ( R 2) > 0.70 and percentage bias (PBIAS) between -7 and +18 for calibration and validation periods. With the progression of urbanization, forest remained the main "sink" landscape while cultivated and urban lands remained the main "source" landscapes with the role of orchard and grassland being uncertain and changing with time. Compared to 1984, the landscape use pattern in 2013 increased nutrient discharge by 10%. Nutrient loads modelled under wet climate were 3-4 times higher than that under dry climate for the same landscape pattern. Results indicate that climate change could impose a far greater impact on runoff and nutrient discharge in a peri-urban watershed than landscape pattern change.

Water-quality assessment of the Lower Susquehanna River Basin, Pennsylvania and Maryland; sources, characteristics, analysis and limitations of nutrient and suspended-sediment data, 1975-90

USGS Publications Warehouse

Hainly, R.A.; Loper, C.A.

1997-01-01

This report describes analyses of available information on nutrients and suspended sediment collected in the Lower Susquehanna River Basin during water years 1975-90. Most of the analyses were applied to data collected during water years 1980-89. The report describes the spatial and temporal availability of nutrient and suspended-sediment data and presents a preliminary concept of the spatial and temporal patterns of concentrations and loads within the basin. Where data were available, total and dissolved forms of nitrogen and phosphorus species from precipitation, surface water, ground water, and springwater, and bottom material from streams and reservoirs were evaluated. Suspended-sediment data from streams also were evaluated. The U.S. Geological Survey National Water Information System (NWIS) database was selected as the primary database for the analyses. Precipitation-quality data from the National Atmospheric Deposition Program (NADP) and bottom-material-quality data from the National Uranium Resource Evaluation (NURE) were used to supplement the water-quality data from NWIS. Concentrations of nutrients were available from 3 precipitation sites established for longterm monitoring purposes, 883 wells (854 synoptic areal survey sites and 29 project and research sites), 23 springs (17 synoptic areal survey sites and 6 project and research sites), and 894 bottom-material sites (840 synoptic areal survey sites and 54 project and research sites). Concentrations of nutrients and (or) suspended sediment were available from 128 streams (36 long-term monitoring sites, 51 synoptic areal survey sites, and 41 project and research sites). Concentrations of nutrients and suspended sediment in streams varied temporally and spatially and were related to land use, agricultural practices, and streamflow. A general north-to-south pattern of increasing median nitrate concentrations, from 2 to 5 mg/L, was detected in samples collected in study unit streams. In streams that drain areas dominated by agriculture, concentrations of nutrients and suspended sediment tend to be elevated with respect to those found in areas of other land-use types and are related to the amount of commercial fertilizer and animal manure applied to the area drained by the streams. Animal manure is the dominant source of nitrogen for the streams in the lower, agricultural part of the basin. Concentrations of nutrients in samples from wells varied with season and well depth and were related to hydrogeologic setting. Median concentrations of nitrate were 2.5 and 3.5 mg/L for wells drawing water at depths of 0 to 100 ft and 101 to 200 ft, respectively. The lowest median concentrations for nitrate in ground water from wells were generally found in siliciclastic-bedrock, forested settings of the Ridge and Valley Physiographic Province, and the highest were found in carbonate-bedrock agricultural settings of the Piedmont Physiographic Province. Twenty-five percent of the measurements from wells in carbonate rocks in the Piedmont Physiographic Province exceeded the Pennsylvania drinking-water standard. An estimate of mass balance of nutrient loads within the Lower Susquehanna River Basin was produced by combining the available information on stream loads, atmosphericdeposition loads, commercial-fertilizer applications, animal-manure production, privateseptic-system nonpoint-source loads, and municipal and industrial point-source loads. The percentage of the average annual nitrate load carried in base flow of streams in the study unit ranged from 45 to 76 percent, and the average annual phosphorus load carried in base flow ranged from 20 to 33 percent. Average annual yields of nutrients and suspended sediment from tributary basins are directly related to percentage of drainage area in agriculture and inversely to drainage area. Information required to compute loads of nitrogen and phosphorus were available for all sources except atmospheric deposition, for which only nitrogen data were available. Atmospheric deposition is the dominant source of nitrogen for the mostly forested basins draining the upper half of the study unit. The estimate of total annual nitrogen load to the study unit from precipitation is 98.8 million pounds. Nonpoint and point sources of nutrients were estimated. Nonpoint and point sources combined, including atmospheric deposition, provide a potential annual load of 390 million pounds of nitrogen and 79.5 million pounds of phosphorus. The range of percentages of the estimated nonpoint and point sources that were measured in the stream was 20 to 47 percent for nitrogen and 6 to 14 percent for phosphorus. On the average, the Susquehanna River discharges 141,000 pounds of nitrogen and 7,920 pounds of phosphorus to the Lower Susquehanna River reservoir system each year. About 98 percent of the nitrogen and 60 percent of the phosphorus passes through the reservoir system. Interpretations of available water-quality data and conclusions about the water quality of the Lower Susquehanna River Basin were limited by the scarcity of certain types of water-quality data and current ancillary data. A more complete assessment of the water quality of the basin with respect to nutrients and suspended sediment would be enhanced by the availability of additional data for multiple samples over time from all water environments; samples from streams in the northern and western part of the basin; samples from streams and springs throughout the basin during high base-flow or stormflow conditions; and information on current land-use, and nutrient loading from all types of land-use settings.

Trends in nutrient concentrations, loads, and yields in streams in the Sacramento, San Joaquin, and Santa Ana Basins, California, 1975-2004

USGS Publications Warehouse

Kratzer, Charles R.; Kent, Robert; Seleh, Dina K.; Knifong, Donna L.; Dileanis, Peter D.; Orlando, James L.

2011-01-01

A comprehensive database was assembled for the Sacramento, San Joaquin, and Santa Ana Basins in California on nutrient concentrations, flows, and point and nonpoint sources of nutrients for 1975-2004. Most of the data on nutrient concentrations (nitrate, ammonia, total nitrogen, orthophosphate, and total phosphorus) were from the U.S. Geological Survey's National Water Information System database (35.2 percent), the California Department of Water Resources (21.9 percent), the University of California at Davis (21.6 percent), and the U.S. Environmental Protection Agency's STOrage and RETrieval database (20.0 percent). Point-source discharges accounted for less than 1 percent of river flows in the Sacramento and San Joaquin Rivers, but accounted for close to 80 percent of the nonstorm flow in the Santa Ana River. Point sources accounted for 4 and 7 percent of the total nitrogen and total phosphorus loads, respectively, in the Sacramento River at Freeport for 1985-2004. Point sources accounted for 8 and 17 percent of the total nitrogen and total phosphorus loads, respectively, in the San Joaquin River near Vernalis for 1985-2004. The volume of wastewater discharged into the Santa Ana River increased almost three-fold over the study period. However, due to improvements in wastewater treatment, the total nitrogen load to the Santa Ana River from point sources in 2004 was approximately the same as in 1975 and the total phosphorus load in 2004 was less than in 1975. Nonpoint sources of nutrients estimated in this study included atmospheric deposition, fertilizer application, manure production, and tile drainage. The estimated dry deposition of nitrogen exceeded wet deposition in the Sacramento and San Joaquin Valleys and in the basin area of the Santa Ana Basin, with ratios of dry to wet deposition of 1.7, 2.8, and 9.8, respectively. Fertilizer application increased appreciably from 1987 to 2004 in all three California basins, although manure production increased in the San Joaquin Basin but decreased in the Sacramento and Santa Ana Basins from 1982 to 2002. Tile drainage accounted for 22 percent of the total nitrogen load in the San Joaquin River near Vernalis for 1985-2004. Nutrient loads and trends were calculated by using the log-linear multiple-regression model, LOADEST. Loads were calculated for water years 1975-2004 for 22 sites in the Sacramento Basin, 15 sites in the San Joaquin Basin, and 6 sites in the Santa Ana Basin. The average annual load of total nitrogen and total phosphorus for 1985-2004 in subbasins in the Sacramento and San Joaquin Basins were divided by their drainage areas to calculate average annual yield. Total nitrogen yields were greater than 2.45 tons per square mile per year [(tons/mi2)/yr] in about 61 percent of the valley floor in the San Joaquin Basin compared with only about 12 percent of the valley floor in the Sacramento Basin. Total phosphorus yields were greater than 0.34 (tons/mi2)/yr in about 43 percent of the valley floor in the San Joaquin Basin compared with only about 5 percent in the valley floor of the Sacramento Basin. In a stepwise multiple linear-regression analysis of 30 subbasins in the Sacramento and San Joaquin Basins, the most important explanatory variables (out of 11 variables) for the response variable (total nitrogen yield) were the percentage of land use in (1) orchards and vineyards, (2) row crops, and (3) urban categories. For total phosphorus yield, the most important explanatory variable was the amount of fertilizer application plus manure production. Trends were evaluated for three time periods: 1975-2004, 1985-2004, and 1993-2004. Most trends in flow-adjusted concentrations of nutrients in the Sacramento Basin were downward for all three time periods. The decreasing nutrient trends in the American River at Sacramento and the Sacramento River at Freeport for 1975-2004 were attributed to the consolidation of wastewater in the Sacramento metropolitan area in December 1982 to

Water-quality assessment of the largely urban blue river basin, Metropolitan Kansas City, USA, 1998 to 2007

USGS Publications Warehouse

Wilkison, D.H.; Armstrong, D.J.; Hampton, S.A.

2009-01-01

From 1998 through 2007, over 750 surface-water or bed-sediment samples in the Blue River Basin - a largely urban basin in metropolitan Kansas City - were analyzed for more than 100 anthropogenic compounds. Compounds analyzed included nutrients, fecal-indicator bacteria, suspended sediment, pharmaceuticals and personal care products. Non-point source runoff, hydrologic alterations, and numerous waste-water discharge points resulted in the routine detection of complex mixtures of anthropogenic compounds in samples from basin stream sites. Temporal and spatial variations in concentrations and loads of nutrients, pharmaceuticals, and organic wastewater compounds were observed, primarily related to a site's proximity to point-source discharges and stream-flow dynamics. ?? 2009 ASCE.

A hydrologic network supporting spatially referenced regression modeling in the Chesapeake Bay watershed

USGS Publications Warehouse

Brakebill, J.W.; Preston, S.D.

2003-01-01

The U.S. Geological Survey has developed a methodology for statistically relating nutrient sources and land-surface characteristics to nutrient loads of streams. The methodology is referred to as SPAtially Referenced Regressions On Watershed attributes (SPARROW), and relates measured stream nutrient loads to nutrient sources using nonlinear statistical regression models. A spatially detailed digital hydrologic network of stream reaches, stream-reach characteristics such as mean streamflow, water velocity, reach length, and travel time, and their associated watersheds supports the regression models. This network serves as the primary framework for spatially referencing potential nutrient source information such as atmospheric deposition, septic systems, point-sources, land use, land cover, and agricultural sources and land-surface characteristics such as land use, land cover, average-annual precipitation and temperature, slope, and soil permeability. In the Chesapeake Bay watershed that covers parts of Delaware, Maryland, Pennsylvania, New York, Virginia, West Virginia, and Washington D.C., SPARROW was used to generate models estimating loads of total nitrogen and total phosphorus representing 1987 and 1992 land-surface conditions. The 1987 models used a hydrologic network derived from an enhanced version of the U.S. Environmental Protection Agency's digital River Reach File, and course resolution Digital Elevation Models (DEMs). A new hydrologic network was created to support the 1992 models by generating stream reaches representing surface-water pathways defined by flow direction and flow accumulation algorithms from higher resolution DEMs. On a reach-by-reach basis, stream reach characteristics essential to the modeling were transferred to the newly generated pathways or reaches from the enhanced River Reach File used to support the 1987 models. To complete the new network, watersheds for each reach were generated using the direction of surface-water flow derived from the DEMs. This network improves upon existing digital stream data by increasing the level of spatial detail and providing consistency between the reach locations and topography. The hydrologic network also aids in illustrating the spatial patterns of predicted nutrient loads and sources contributed locally to each stream, and the percentages of nutrient load that reach Chesapeake Bay.

External nutrient sources, internal nutrient pools, and phytoplankton production in Chesapeake Bay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magnien, R.E.; Summers, R.M.; Sellner, K.G.

1992-12-01

External nutrient loadings, internal nutrient pools, and phytoplankton production were examined for three major subsystems of the Chesapeake Bay Estuary-the upper Mainstem, the Patuxent Estuary, and the Potomac Estuary-during 1985-1989. The atomic nitrogen to phosphorus ratios (TN:TP) of total loads were 51, 29 and 35, respectively. Most of these loads entered at the head of the estuaries from riverine sources and major wastewater treatment plants. Seven-16% of the nitrogen load entered the head of each estuary as particulate matter in contrast to 48-69% for phosphorus. The difference seems to favor a greater loss of phosphorus than nitrogen through sedimentation andmore » burial. A major storm event in the Potomac watershed greatly increased the particulate fraction of nitrogen and phosphorus and lowered the TN:TP in the river-borne loads and accounted for 11% of the nitrogen and 31% of the phosphorus delivered to the estuary by the Potomac River during the entire 60- month period examined here. Within the Mainstem estuary, salinity dilution plots revealed strong net sources of ammonium and phosphate in the oligohaline to upper mesohaline region. indicating considerable internal recycling of nutrients to surface waters. A net sink of nitrate was indicated during summer. Phytoplankton biomass in the mesohaline Mainstem reached a peak in spring and was relatively constant throughout the other seasons. In the Patuxent and Potomac, the TN:TP ratios of external loads are 2-4 times higher than those observed over the previous two decades. These changes are attributed to point-source phosphorus controls and the likelihood that nitrogen-rich nonpoint source inputs, including contributions from the atmosphere, have increased. These higher N:P ratios now suggest a greater overall potential for phosphorus-limitation rather than nitrogen-limitation of phytoplankton in the areas studied. 66 refs., 6 figs., 7 tabs.« less

Investigating the effects of point source and nonpoint source pollution on the water quality of the East River (Dongjiang) in South China

USGS Publications Warehouse

Wu, Yiping; Chen, Ji

2013-01-01

Understanding the physical processes of point source (PS) and nonpoint source (NPS) pollution is critical to evaluate river water quality and identify major pollutant sources in a watershed. In this study, we used the physically-based hydrological/water quality model, Soil and Water Assessment Tool, to investigate the influence of PS and NPS pollution on the water quality of the East River (Dongjiang in Chinese) in southern China. Our results indicate that NPS pollution was the dominant contribution (>94%) to nutrient loads except for mineral phosphorus (50%). A comprehensive Water Quality Index (WQI) computed using eight key water quality variables demonstrates that water quality is better upstream than downstream despite the higher level of ammonium nitrogen found in upstream waters. Also, the temporal (seasonal) and spatial distributions of nutrient loads clearly indicate the critical time period (from late dry season to early wet season) and pollution source areas within the basin (middle and downstream agricultural lands), which resource managers can use to accomplish substantial reduction of NPS pollutant loadings. Overall, this study helps our understanding of the relationship between human activities and pollutant loads and further contributes to decision support for local watershed managers to protect water quality in this region. In particular, the methods presented such as integrating WQI with watershed modeling and identifying the critical time period and pollutions source areas can be valuable for other researchers worldwide.

Effectiveness of SWAT in characterizing the watershed hydrology in the snowy-mountainous Lower Bear Malad River (LBMR) watershed in Box Elder County, Utah

NASA Astrophysics Data System (ADS)

Salha, A. A.; Stevens, D. K.

2015-12-01

Distributed watershed models are essential for quantifying sediment and nutrient loads that originate from point and nonpoint sources. Such models are primary means towards generating pollutant estimates in ungaged watersheds and respond well at watershed scales by capturing the variability in soils, climatic conditions, land uses/covers and management conditions over extended periods of time. This effort evaluates the performance of the Soil and Water Assessment Tool (SWAT) model as a watershed level tool to investigate, manage, and characterize the transport and fate of nutrients in Lower Bear Malad River (LBMR) watershed (Subbasin HUC 16010204) in Utah. Water quality concerns have been documented and are primarily attributed to high phosphorus and total suspended sediment concentrations caused by agricultural and farming practices along with identified point sources (WWTPs). Input data such as Digital Elevation Model (DEM), land use/Land cover (LULC), soils, and climate data for 10 years (2000-2010) is utilized to quantify the LBMR streamflow. Such modeling is useful in developing the required water quality regulations such as Total Maximum Daily Loads (TMDL). Measured concentrations of nutrients were closely captured by simulated monthly nutrient concentrations based on the R2 and Nash- Sutcliffe fitness criteria. The model is expected to be able to identify contaminant non-point sources, identify areas of high pollution risk, locate optimal monitoring sites, and evaluate best management practices to cost-effectively reduce pollution and improve water quality as required by the LBMR watershed's TMDL.

Modeling Nutrient Loading to Watersheds in the Great Lakes Basin: A Detailed Source Model at the Regional Scale

NASA Astrophysics Data System (ADS)

Luscz, E.; Kendall, A. D.; Martin, S. L.; Hyndman, D. W.

2011-12-01

Watershed nutrient loading models are important tools used to address issues including eutrophication, harmful algal blooms, and decreases in aquatic species diversity. Such approaches have been developed to assess the level and source of nutrient loading across a wide range of scales, yet there is typically a tradeoff between the scale of the model and the level of detail regarding the individual sources of nutrients. To avoid this tradeoff, we developed a detailed source nutrient loading model for every watershed in Michigan's lower peninsula. Sources considered include atmospheric deposition, septic tanks, waste water treatment plants, combined sewer overflows, animal waste from confined animal feeding operations and pastured animals, as well as fertilizer from agricultural, residential, and commercial sources and industrial effluents . Each source is related to readily-available GIS inputs that may vary through time. This loading model was used to assess the importance of sources and landscape factors in nutrient loading rates to watersheds, and how these have changed in recent decades. The results showed the value of detailed source inputs, revealing regional trends while still providing insight to the existence of variability at smaller scales.

Character and Trends of Water Quality in the Blue River Basin, Kansas City Metropolitan Area, Missouri and Kansas, 1998 through 2007

USGS Publications Warehouse

Wilkison, Donald H.; Armstrong, Daniel J.; Hampton, Sarah A.

2009-01-01

Water-quality and ecological character and trends in the metropolitan Blue River Basin were evaluated from 1998 through 2007 to provide spatial and temporal resolution to factors that affect the quality of water and biota in the basin and provide a basis for assessing the efficacy of long-term combined sewer control and basin management plans. Assessments included measurements of stream discharge, pH, dissolved oxygen, specific conductance, turbidity, nutrients (dissolved and total nitrogen and phosphorus species), fecal-indicator bacteria (Escherichia coli and fecal coliform), suspended sediment, organic wastewater and pharmaceutical compounds, and sources of these compounds as well as the quality of stream biota in the basin. Because of the nature and myriad of factors that affect basin water quality, multiple strategies are needed to decrease constituent loads in streams. Strategies designed to decrease or eliminate combined sewer overflows (CSOs) would substantially reduce the annual loads of nutrients and fecal-indicator bacteria in Brush Creek, but have little effect on Blue River loadings. Nonpoint source reductions to Brush Creek could potentially have an equivalent, if not greater, effect on water quality than would CSO reductions. Nonpoint source reductions could also substantially decrease annual nutrient and bacteria loadings to the Blue River and Indian Creek. Methods designed to decrease nutrient loads originating from Blue River and Indian Creek wastewater treatment plants (WWTPs) could substantially reduce the overall nutrient load in these streams. For the main stem of the Blue River and Indian Creek, primary sources of nutrients were nonpoint source runoff and WWTPs discharges; however, the relative contribution of each source varied depending on how wet or dry the year was and the number of upstream WWTPs. On Brush Creek, approximately two-thirds of the nutrients originated from nonpoint sources and the remainder from CSOs. Nutrient assimilation processes, which reduced total nitrogen loads by approximately 13 percent and total phosphorus loads by double that amount in a 20-kilometer reach of the Blue River during three synoptic base-flow sampling events between August through September 2004 and September 2005, likely are limited to selected periods during any given year and may not substantially reduce annual nutrient loads. Bacteria densities typically increased with increasing urbanization, and bacteria loadings to the Blue River and Indian Creek were almost entirely the result of nonpoint source runoff. WWTPs contributed, on average, less than 1 percent of the bacteria to these reaches, and in areas of the Blue River that had combined sewers, CSOs contributed only minor amounts (less than 2 percent) of the total annual load in 2005. The bulk of the fecal-indicator bacteria load in Brush Creek also originated from nonpoint sources with the remainder from CSOs. From October 2002 through September 2007, estimated daily mean Escherichia coli bacteria density in upper reaches of the Blue River met the State of Missouri secondary contact criterion standard approximately 85 percent of the time. However, in lower Blue River reaches, the same threshold was exceeded approximately 45 percent of the time. The tributary with the greatest number of CSO discharge points, Brush Creek, contributed approximately 10 percent of the bacteria loads to downstream reaches. The tributary Town Fork Creek had median base-flow Escherichia coli densities that were double that of other basin sites and stormflow densities 10 times greater than those in other parts of the basin largely because approximately one-fourth of the runoff in the Town Fork Creek Basin is believed to originate in combined sewers. Genotypic source typing of bacteria indicated that more than half of the bacteria in this tributary originated from human sources with two storms contributing the bulk of all bacteria sourced as human. However, areas outsid

Enhancing nitrogen removal in stormwater treatment facilities for transportation.

DOT National Transportation Integrated Search

2015-01-01

Stormwater from roadways is a point source of pollution. State DOTs must comply with Total Maximum : Daily Load (TMDL) regulations for nutrients such as nitrogen, which causes water quality impairment. Existing stormwater treatment technologies, such...

Pollution loads in urban runoff and sanitary wastewater.

PubMed

Taebi, Amir; Droste, Ronald L

2004-07-05

While more attention has been paid in recent years to urban point source pollution control through the establishment of wastewater treatment plants in many developing countries, no considerable planning nor any serious measures have been taken to control urban non-point source pollution (urban stormwater runoff). The present study is a screening analysis to investigate the pollution loads in urban runoff compared to point source loads as a first prerequisite for planning and management of receiving water quality. To compare pollutant loads from point and non-point urban sources, the pollutant load is expressed as the weight of pollutant per hectare area per year (kg/ha.year). Unit loads were estimated in stormwater runoff, raw sanitary wastewater and secondary treatment effluents in Isfahan, Iran. Results indicate that the annual pollution load in urban runoff is lower than the annual pollution load in sanitary wastewater in areas with low precipitation but it is higher in areas with high precipitation. Two options, namely, advanced treatment (in lieu of secondary treatment) of sanitary wastewater and urban runoff quality control systems (such as detention ponds) were investigated as controlling systems for pollution discharges into receiving waters. The results revealed that for Isfahan, as a low precipitation urban area, advanced treatment is a more suitable option, but for high precipitation urban areas, urban surface runoff quality control installations were more effective for suspended solids and oxygen-demanding matter controls, and that advanced treatment is the more effective option for nutrient control.

Nitrogen and phosphorus in streams of the Great Miami River Basin, Ohio, 1998-2000

USGS Publications Warehouse

Reutter, David C.

2003-01-01

Sources and loads of nitrogen and phosphorus in streams of the Great Miami River Basin were evaluated as part of the National Water-Quality Assessment program. Water samples were collected by the U.S. Geological Survey from October 1998 through September 2000 (water years 1999 and 2000) at five locations in Ohio on a routine schedule and additionally during selected high streamflows. Stillwater River near Union, Great Miami River near Vandalia, and Mad River near Eagle City were selected to represent predominantly agricultural areas upstream from the Dayton metropolitan area. Holes Creek near Kettering is in the Dayton metropolitan area and was selected to represent an urban area in the Great Miami River Basin. Great Miami River at Hamilton is downstream from the Dayton and Hamilton-Middletown metropolitan areas and was selected to represent mixed agricultural and urban land uses of the Great Miami River Basin. Inputs of nitrogen and phosphorus to streams from point and nonpoint sources were estimated for the three agricultural basins and for the Great Miami River Basin as a whole. Nutrient inputs from point sources were computed from the facilities that discharge one-half million gallons or more per day into streams of the Great Miami River Basin. Nonpoint-source inputs estimated in this report are atmospheric deposition and commercial-fertilizer and manure applications. Loads of ammonia, nitrate, total nitrogen, orthophosphate, and total phosphorus from the five sites were computed with the ESTIMATOR program. The computations show nitrate to be the primary component of instream nitrogen loads, and particulate phosphorus to be the primary component of instream phosphorus loads. The Mad River contributed the smallest loads of total nitrogen and total phosphorus to the study area upstream from Dayton, whereas the Upper Great Miami River (upstream from Vandalia) contributed the largest loads of total nitrogen and total phosphorus to the Great Miami River Basin upstream from Dayton. An evaluation of monthly mean loads shows that nutrient loads were highest during winter 1999 and lowest during the drought of summer and autumn 1999. During the 1999 drought, point sources were the primary contributors of nitrogen and phosphorus loads to most of the study area. Nonpoint sources, however, were the primary contributors of nitrogen and phosphorus loads during months of high streamflow. Nonpoint sources were also the primary contributors of nitrogen loads to the Mad River during the 1999 drought, owing to unusually large amounts of ground-water discharge to the stream. The Stillwater River Basin had the highest nutrient yields in the study area during months of high streamflow; however, the Mad River Basin had the highest yields of all nutrients except ammonia during the months of the 1999 drought. The high wet-weather yields in the Stillwater River Basin were caused by agricultural runoff, whereas high yields in the Mad River Basin during drought resulted from the large, sustained contribution of ground water to streamflow throughout the year. In the basins upstream from Dayton, an estimated 19 to 25 percent of the nonpoint source of nitrogen and 4 to 5 percent of the nonpoint source of phosphorus that was deposited or applied to the land was transported into streams.

Pathogen reduction co-benefits of nutrient best management practices

PubMed Central

Wainger, Lisa A.; Barber, Mary C.

2016-01-01

Background Many of the practices currently underway to reduce nitrogen, phosphorus, and sediment loads entering the Chesapeake Bay have also been observed to support reduction of disease-causing pathogen loadings. We quantify how implementation of these practices, proposed to meet the nutrient and sediment caps prescribed by the Total Maximum Daily Load (TMDL), could reduce pathogen loadings and provide public health co-benefits within the Chesapeake Bay system. Methods We used published data on the pathogen reduction potential of management practices and baseline fecal coliform loadings estimated as part of prior modeling to estimate the reduction in pathogen loadings to the mainstem Potomac River and Chesapeake Bay attributable to practices implemented as part of the TMDL. We then compare the estimates with the baseline loadings of fecal coliform loadings to estimate the total pathogen reduction potential of the TMDL. Results We estimate that the TMDL practices have the potential to decrease disease-causing pathogen loads from all point and non-point sources to the mainstem Potomac River and the entire Chesapeake Bay watershed by 19% and 27%, respectively. These numbers are likely to be underestimates due to data limitations that forced us to omit some practices from analysis. Discussion Based on known impairments and disease incidence rates, we conclude that efforts to reduce nutrients may create substantial health co-benefits by improving the safety of water-contact recreation and seafood consumption. PMID:27904807

Pathogen reduction co-benefits of nutrient best management practices.

PubMed

Richkus, Jennifer; Wainger, Lisa A; Barber, Mary C

2016-01-01

Many of the practices currently underway to reduce nitrogen, phosphorus, and sediment loads entering the Chesapeake Bay have also been observed to support reduction of disease-causing pathogen loadings. We quantify how implementation of these practices, proposed to meet the nutrient and sediment caps prescribed by the Total Maximum Daily Load (TMDL), could reduce pathogen loadings and provide public health co-benefits within the Chesapeake Bay system. We used published data on the pathogen reduction potential of management practices and baseline fecal coliform loadings estimated as part of prior modeling to estimate the reduction in pathogen loadings to the mainstem Potomac River and Chesapeake Bay attributable to practices implemented as part of the TMDL. We then compare the estimates with the baseline loadings of fecal coliform loadings to estimate the total pathogen reduction potential of the TMDL. We estimate that the TMDL practices have the potential to decrease disease-causing pathogen loads from all point and non-point sources to the mainstem Potomac River and the entire Chesapeake Bay watershed by 19% and 27%, respectively. These numbers are likely to be underestimates due to data limitations that forced us to omit some practices from analysis. Based on known impairments and disease incidence rates, we conclude that efforts to reduce nutrients may create substantial health co-benefits by improving the safety of water-contact recreation and seafood consumption.

Nutrient loadings to streams of the continental United States from municipal and industrial effluent?

USGS Publications Warehouse

Maupin, Molly A.; Ivahnenko, Tamara

2011-01-01

Data from the United States Environmental Protection Agency Permit Compliance System national database were used to calculate annual total nitrogen (TN) and total phosphorus (TP) loads to surface waters from municipal and industrial facilities in six major regions of the United States for 1992, 1997, and 2002. Concentration and effluent flow data were examined for approximately 118,250 facilities in 45 states and the District of Columbia. Inconsistent and incomplete discharge locations, effluent flows, and effluent nutrient concentrations limited the use of these data for calculating nutrient loads. More concentrations were reported for major facilities, those discharging more than 1 million gallons per day, than for minor facilities, and more concentrations were reported for TP than for TN. Analytical methods to check and improve the quality of the Permit Compliance System data were used. Annual loads were calculated using "typical pollutant concentrations" to supplement missing concentrations based on the type and size of facilities. Annual nutrient loads for over 26,600 facilities were calculated for at least one of the three years. Sewage systems represented 74% of all TN loads and 58% of all TP loads. This work represents an initial set of data to develop a comprehensive and consistent national database of point-source nutrient loads. These loads can be used to inform a wide range of water-quality management, watershed modeling, and research efforts at multiple scales.

Effects of nutrient load on microbial activities within a seagrass-dominated ecosystem: Implications of changes in seagrass blue carbon.

PubMed

Liu, Songlin; Jiang, Zhijian; Wu, Yunchao; Zhang, Jingping; Arbi, Iman; Ye, Feng; Huang, Xiaoping; Macreadie, Peter Ian

2017-04-15

Nutrient loading is a leading cause of global seagrass decline, triggering shifts from seagrass- to macroalgal-dominance. Within seagrass meadows of Xincun Bay (South China Sea), we found that nutrient loading (due to fish farming) increased sediment microbial biomass and extracellular enzyme activity associated with carbon cycling (polyphenol oxidase, invertase and cellulase), with a corresponding decrease in percent sediment organic carbon (SOC), suggesting that nutrients primed microorganism and stimulated SOC remineralization. Surpisingly, however, the relative contribution of seagrass-derived carbon to bacteria (δ 13 C bacteria ) increased with nutrient loading, despite popular theory being that microbes switch to consuming macroalgae which are assumed to provide a more labile carbon source. Organic carbon sources of fungi were unaffected by nutrient loading. Overall, this study suggests that nutrient loading changes the relative contribution of seagrass and algal sources to SOC pools, boosting sediment microbial biomass and extracellular enzyme activity, thereby possibly changing seagrass blue carbon. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evaluation and use of U.S. Environmental Protection Agency Clean Watersheds Needs Survey data to quantify nutrient loads to surface water, 1978–2012

USGS Publications Warehouse

Ivahnenko, Tamara I.

2017-12-07

Changes in municipal and industrial point-source discharges over time have been an important factor affecting nutrient trends in many of the Nation’s streams and rivers. This report documents how three U.S. Environmental Protection Agency (EPA) national datasets—the Permit Compliance System, the Integrated Compliance Information System, and the Clean Watersheds Needs Survey—were evaluated for use in the U.S. Geological Survey National Water-Quality Assessment project to assess the causes of nutrient trends. This report also describes how a database of total nitrogen load and total phosphorous load was generated for select wastewater treatment facilities in the United States based on information reported in the EPA Clean Watersheds Needs Survey. Nutrient loads were calculated for the years 1978, 1980, 1982, 1984, 1986, 1988, 1990, 1992, 1996, 2000, 2004, 2008, and 2012 based on average nitrogen and phosphorous concentrations for reported treatment levels and on annual reported flow values.The EPA Permit Compliance System (PCS) and Integrated Compliance Information System (ICIS), which monitor point-source facility discharges, together are the Nation’s most spatially comprehensive dataset for nutrients released to surface waters. However, datasets for many individual facilities are incomplete, the PCS/ICIS historical data date back only to 1989, and historical data are available for only a limited number of facilities. Additionally, inconsistencies in facility reporting make it difficult to track or identify changes in nutrient discharges over time. Previous efforts made by the U.S. Geological Survey to “fill in” gaps in the PCS/ICIS data were based on statistical methods—missing data were filled in through the use of a statistical model based on the Standard Industrial Classification code, size, and flow class of the facility and on seasonal nutrient discharges of similar facilities. This approach was used to estimate point-source loads for a single point in time; it was not evaluated for use in generating a consistent data series over time.Another national EPA dataset that is available is the Clean Watersheds Needs Survey (CWNS), conducted every 4 years beginning 1973. The CWNS is an assessment of the capital needs of wastewater facilities to meet the water-quality goals set in the Clean Water Act. Data collected about these facilities include location and contact information for the facilities; population served; flow and treatment level of the facility; estimated capital needs to upgrade, repair, or improve facilities for water quality; and nonpoint-source best management practices.Total nitrogen and total phosphorous load calculations for each of the CWNS years were based on treatment level information and average annual outflow (in million gallons per day) from each of the facilities that had reported it. Treatment levels categories (such as Primary, Secondary, or Advanced) were substituted with average total nitrogen and total phosphorous concentrations for each treatment level based on those reported in literature. The CWNS dataset, like the PCS/ICIS dataset, has years where facilities did not report either a treatment level or an annual average outflow, or both. To fill in the data gaps, simple linear assumptions were made based on each facility’s responses to the survey in years bracketing the data gap or immediately before or after the data gap if open ended. Treatment level and flow data unique to each facility were used to complete the CWNS dataset for that facility.

Testing of The Harp Guidelines On A Small Watershed In Finland

NASA Astrophysics Data System (ADS)

Granlund, K.; Rekolainen, S.

TESTING of THE HARP GUIDELINES ON A SMALL WATERSHED IN FIN- LAND K. Granlund, S. Rekolainen Finnish Environment Institute, Research Department kirsti.granlund@vyh.fi Watersheds have emerged as environmental units for assessing, controlling and reduc- ing non-point-source pollution. Within the framework of the international conventions, such as OSPARCOM, HELCOM, and in the implementation of the EU Water Frame- work Directive, the criteria for model selection is of key importance. Harmonized Quantification and Reporting Procedures for Nutrients (HARP) aims at helping the implementation of OSPAR's (Convention for the Protection of the Marine Environ- ment of the North-East Atlantic) strategy in controlling eutrophication and reducing nutrient input to marine ecosystems by 50nitrogen and phosphorus losses from both point and nonpoint sources and help assess the effectiveness of the pollution reduction strategy. The HARP guidelines related respectively to the "Quantification of Nitrogen and Phosphorus Losses from Diffuse Anthropogenic Sources and Natural Background Losses" and to the "Quantification and Reporting of the Retention of Nitrogen and Phosphorus in River Catchments" were tested on a small, well instrumented agricul- tural watershed in Finland. The project was coordinated by the Environment Institute of the Joint Research Centre. Three types of methodologies for estimating nutrient losses to watercourses were eval- uated during the project. Simple methods based on regression equations or loading functions provide a quick method for estimating nutrient losses. Through these meth- ods the pollutant load can be related to parameters such as slope, soil type, land-use, management practices etc. Relevant nutrient loading functions for the study catch- ment were collected during the project. One mid-range model was applied to simulate the nitrogen cycle in a simplified manner in relation to climate, soil properties, land- use and management practices. Physically based models describe in detail the water and nutrient cycle within the watershed. ICECREAM and SWAT models were applied on the study watershed. ICECREAM is a management model based on CREAMS model for predicting field-scale runoff and erosion. The nitrogen and phosphorus sub- models are based on GLEAMS model. SWAT is a continuous time and spatially dis- tributed model, which includes hydrological, sediment and chemical processes in river 1 basins.The simple methods and the mid-range model for nitrogen proved to be fast and easy to apply, but due limited information on crop-specific loading functions and ni- trogen process rates (e.g. mineralisation in soil), only order-of-magnitude estimates for nutrient loads could be calculated. The ICECREAM model was used to estimate crop-specific nutrient losses from the agricultural area. The potential annual nutrient loads for the whole catchment were then calculated by including estimates for nutri- ent loads from other land-use classes (forested area and scattered settlement). Finally, calibration of the SWAT model was started to study in detail the effects of catchment characteristics on nutrient losses. The preliminary results of model testing are pre- sented and the suitability of different methodologies for estimating nutrient losses in Finnish catchments is discussed. 2

Instream Attenuation of Nitrogen and Phosphorus in Non-Point Source Dominated Streams: Hydrologic and Biogeochemical Controls

NASA Astrophysics Data System (ADS)

Bray, E. N.; Chen, X.; Keller, A. A.

2010-12-01

Non-point source inputs of total nitrogen (TN) and total phosphorus (TP) in rivers are the leading causes of water quality degradation in the United States (Turner and Rabalais, 2003; Broussard and Turner, 2009). Yet it remains a challenge to adequately quantify the relative role and influence of physical hydrological processes versus biogeochemical processes on the attenuation of TN and TP for individual river reaches. A watershed-scale study of instream dynamics and attenuation of TN and TP in northeastern U.S. headwater streams demonstrates that physical and hydrological processes exert greater control over nutrient removal than biogeochemical processes. To explore these interactions under various attenuation scenarios, we developed the watershed-scale model (WARMF) for 97 catchments to simulate watershed processes, hydrology, and diffuse source loads of nutrients. We simulated a hypothetical nutrient release at a rate of 1 kg/d of TN (50% as ammonium and 50% as nitrate) and TP (100% as phosphate) to predict response lengths of downstream catchments. Resulting attenuation factors are presented as the change in mean load at a given location, normalized to the change in the catchment in which the load is applied. Results indicate that for most catchments, the TN and TP load increase is attenuated from the stream within a few tens of kilometers. Fifty percent attenuation occurs across length scales ranging from a few hundreds of meters to kilometers if the load is introduced in the headwaters, indicating the most rapid nutrient removal occurs in the smallest headwater streams but generally decreases with distance downstream. There are some differences in the attenuation factors for TN and TP, although the pattern of attenuation is the same. Sensitivity analyses highlight five hydrological parameters of paramount importance to concentrations of N and P, namely precipitation, evaporation coefficients (magnitude and skewness), soil layer thickness, soil saturated moisture and soil hydraulic conductivity. These model parameters have a significant effect on the concentrations of nutrients, with TN exhibiting greater sensitivity. Further, attenuation results suggest that stream depth, flow regime, and density of agriculture in small headwater streams are potentially important controls to nutrient uptake and removal; i.e. during periods of low flow, dilution is reduced, attenuation length increases, and removal processes may be dominated by settling as opposed to biogeochemistry. Instream attenuation and model results can be used to assess 1) the scale and nature of best management practices which must be adopted to result in nutrient reductions, 2) the downstream distance at which load reductions will be effective, and 3) the hydrological characteristics of the river network which exert considerable influence on attenuation lengths and nutrient removal.

Nutrient pressures and ecological responses to nutrient loading reductions in Danish streams, lakes and coastal waters

NASA Astrophysics Data System (ADS)

Kronvang, Brian; Jeppesen, Erik; Conley, Daniel J.; Søndergaard, Martin; Larsen, Søren E.; Ovesen, Niels B.; Carstensen, Jacob

2005-03-01

The Danish National Aquatic Monitoring and Assessment Programme (NOVA) was launched in 1988 following the adoption of the first Danish Action Plan on the Aquatic Environment in 1987 with the aim to reduce by 50% the nitrogen (N) loading and by 80% the phosphorus (P) loading to the aquatic environment. The 14 years of experience gathered from NOVA have shown that discharges of total N (TN) and P (TP) from point sources to the Danish Aquatic Environment have been reduced by 69% (N) and 82% (P) during the period 1989 2002. Consequently, the P concentration has decreased markedly in most Danish lakes and estuaries. Considerable changes in agricultural practice have resulted in a reduction of the net N-surplus from 136 to 88 kg N ha-1 yr-1 (41%) and the net P-surplus from 19 to 11 kg P ha-1 yr-1 (42%) during the period 1985 2002. Despite these efforts Danish agriculture is today the major source of both N (>80%) and P (>50%) in Danish streams, lakes and coastal waters. A non-parametric statistical trend analysis of TN concentrations in streams draining dominantly agricultural catchments has shown a significant (p<0.05) downward trend in 48 streams with the downward trend being stronger in loamy compared to sandy catchments, and more pronounced with increasing dominance of agricultural exploitation in the catchments. In contrast, a statistical trend analysis of TP concentrations in streams draining agricultural catchments did not reveal any significant trends. The large reduction in nutrient loading from point and non-point sources has in general improved the ecological conditions of Danish lakes in the form of increased summer Secchi depth, decreased chlorophyll a and reduced phytoplankton biomass. Major changes have also occurred in the fish communities in lakes, with positive cascading effects on water quality. In Danish estuaries and coastal waters only a few significant improvements in the ecological quality have been observed, although it is expected that the observed reduced nutrient concentrations are likely to improve the ecological quality of estuaries and coastal waters in Denmark in the long term.

Application of the SPARROW model to assess surface-water nutrient conditions and sources in the United States Pacific Northwest

USGS Publications Warehouse

Wise, Daniel R.; Johnson, Henry M.

2013-01-01

The watershed model SPARROW (Spatially Referenced Regressions on Watershed attributes) was used to estimate mean annual surface-water nutrient conditions (total nitrogen and total phosphorus) and to identify important nutrient sources in catchments of the Pacific Northwest region of the United States for 2002. Model-estimated nutrient yields were generally higher in catchments on the wetter, western side of the Cascade Range than in catchments on the drier, eastern side. The largest source of locally generated total nitrogen stream load in most catchments was runoff from forestland, whereas the largest source of locally generated total phosphorus stream load in most catchments was either geologic material or livestock manure (primarily from grazing livestock). However, the highest total nitrogen and total phosphorus yields were predicted in the relatively small number of catchments where urban sources were the largest contributor to local stream load. Two examples are presented that show how SPARROW results can be applied to large rivers—the relative contribution of different nutrient sources to the total nitrogen load in the Willamette River and the total phosphorus load in the Snake River. The results from this study provided an understanding of the regional patterns in surface-water nutrient conditions and should be useful to researchers and water-quality managers performing local nutrient assessments.

Importance of diffuse pollution control in the Patzcuaro Lake Basin in Mexico.

PubMed

Carro, Marco Mijangos; Dávila, Jorge Izurieta; Balandra, Antonieta Gómez; López, Rubén Hernández; Delgadillo, Rubén Huerto; Chávez, Javier Sánchez; Inclán, Luís Bravo

2008-01-01

In the catchment area of the Lake Patzcuaro in Central Mexico (933 km2) the apportionments of erosion, sediment, nutrients and pathogen coming from thirteen micro basins were estimated with the purpose of identifying critical areas in which best management practices need to be implemented in order to reduce their contribution to the lake pollution and eutrophication. The ArcView Generalized Watershed Loading Functions model (AV-GWLF) was applied to estimate the loads and sources of nutrients. The main results show that the total annual contribution of nitrogen from point sources were 491 tons and from diffuse pollution 2,065 tons, whereas phosphorus loads where 116 and 236 tons, respectively during a thirty year simulation period. Micro basins with predominant agricultural and animal farm land use (56% of the total area) accounts for a high percentage of nitrogen load 33% and phosphorus 52%. On the other hand, Patzcuaro and Quiroga micro basins which comprise approximately 10% of the total catchment area and are the most populated and visited towns by tourist 686,000 people every year, both contributes with 10.1% of the total nitrogen load and 3.2% of phosphorus. In terms of point sources of nitrogen and phosphorus the last towns contribute with 23.5% and 26.6% respectively. Under this situation the adoption of best management practices are an imperative task since the sedimentation and pollution in the lake has increased dramatically in the last twenty years. Copyright (c) IWA Publishing 2008.

Response of Polish rivers (Vistula, Oder) to reduced pressure from point sources and agriculture during the transition period (1988-2008)

NASA Astrophysics Data System (ADS)

Pastuszak, Marianna; Stålnacke, Per; Pawlikowski, Krzysztof; Witek, Zbigniew

2012-06-01

The Vistula and Oder Rivers, two out of the seven largest rivers in the Baltic drainage basin, were responsible for 25% of total riverine nitrogen (TN) and 37% of total riverine phosphorus (TP) input to the Baltic Sea in 2000. The aim of this paper is to evaluate the response of these two rivers to changes that took place in Polish economy during the transition period (1988-2008). The economic changes encompassed: construction of nearly 900 waste water treatment plants in 1999-2008, modernization or closure of obsolete factories, economizing in water consumption, closure or change of ownership of State-owned farms, a drop in fertilizer application, and a decline in livestock stocking. More intensive agriculture and higher point source emissions in the Oder than in the Vistula basin resulted in higher concentrations of TN, nitrate (NO3-N), and TP in the Oder waters in the entire period of our studies. In both rivers, nutrient concentrations and loads showed significant declining trends in the period 1988-2008. TN loads decreased by ca. 20% and 25% in the Vistula and Oder; TP loads dropped by ca. 15% and 65% in the Vistula and Oder. The reduction in phosphorus loads was particularly pronounced in the Oder basin, which was characterized by efficient management systems aiming at mitigation of nutrient emission from the point sources and greater extent of structural changes in agricultural sector during the transition period. The trends in riverine loads are discussed in the paper in relation to socio-economical changes during the transition period, and with respect to physiographic features.

ESTIMATING DIFFUSE STORMWATER NUTRIENT LOADS FROM SUBURBAN LANDSCAPES TO THE NAVESINK ESTUARY, NEW JERSEY

EPA Science Inventory

Hitherto, stormwater runoff from suburban land-uses has been largely unregulated and designated as a non-point source. Phase II of the Clean Water Act will require permits under the National Pollutant Discharge Elimination System for stormwater discharges from municipal separate ...

ESTIMATING DIFFUSE STORMWATER NUTRIENT LOADS FROM SUBURBAN LANDSCAPES IN THE NAVESINK ESTUARY, NEW JERSEY

EPA Science Inventory

Hitherto, stormwater runoff from suburban land-uses has been largely unregulated and designated as a non-point source. Phase II of the Clean Water Act now requires permits under the National Pollutant Discharge Elimination System for stormwater discharges from municipal separate...

Establishing an Anthropogenic Nitrogen Baseline Using Native American Shell Middens

EPA Science Inventory

Narragansett Bay, Rhode Island, has been heavily influenced by anthropogenic nutrients for more than 200 years. Recent efforts to improve water quality have cut sewage nitrogen (N) loads to this point source estuary by more than half. Given that the bay has been heavily fertilize...

Simulation of Temperature, Nutrients, Biochemical Oxygen Demand, and Dissolved Oxygen in the Catawba River, South Carolina, 1996-97

USGS Publications Warehouse

Feaster, Toby D.; Conrads, Paul; Guimaraes, Wladmir B.; Sanders, Curtis L.; Bales, Jerad D.

2003-01-01

Time-series plots of dissolved-oxygen concentrations were determined for various simulated hydrologic and point-source loading conditions along a free-flowing section of the Catawba River from Lake Wylie Dam to the headwaters of Fishing Creek Reservoir in South Carolina. The U.S. Geological Survey one-dimensional dynamic-flow model, BRANCH, was used to simulate hydrodynamic data for the Branched Lagrangian Transport Model. Waterquality data were used to calibrate the Branched Lagrangian Transport Model and included concentrations of nutrients, chlorophyll a, and biochemical oxygen demand in water samples collected during two synoptic sampling surveys at 10 sites along the main stem of the Catawba River and at 3 tributaries; and continuous water temperature and dissolved-oxygen concentrations measured at 5 locations along the main stem of the Catawba River. A sensitivity analysis of the simulated dissolved-oxygen concentrations to model coefficients and data inputs indicated that the simulated dissolved-oxygen concentrations were most sensitive to watertemperature boundary data due to the effect of temperature on reaction kinetics and the solubility of dissolved oxygen. Of the model coefficients, the simulated dissolved-oxygen concentration was most sensitive to the biological oxidation rate of nitrite to nitrate. To demonstrate the utility of the Branched Lagrangian Transport Model for the Catawba River, the model was used to simulate several water-quality scenarios to evaluate the effect on the 24-hour mean dissolved-oxygen concentrations at selected sites for August 24, 1996, as simulated during the model calibration period of August 23 27, 1996. The first scenario included three loading conditions of the major effluent discharges along the main stem of the Catawba River (1) current load (as sampled in August 1996); (2) no load (all point-source loads were removed from the main stem of the Catawba River; loads from the main tributaries were not removed); and (3) fully loaded (in accordance with South Carolina Department of Health and Environmental Control National Discharge Elimination System permits). Results indicate that the 24-hour mean and minimum dissolved-oxygen concentrations for August 24, 1996, changed from the no-load condition within a range of - 0.33 to 0.02 milligram per liter and - 0.48 to 0.00 milligram per liter, respectively. Fully permitted loading conditions changed the 24-hour mean and minimum dissolved-oxygen concentrations from - 0.88 to 0.04 milligram per liter and - 1.04 to 0.00 milligram per liter, respectively. A second scenario included the addition of a point-source discharge of 25 million gallons per day to the August 1996 calibration conditions. The discharge was added at S.C. Highway 5 or at a location near Culp Island (about 4 miles downstream from S.C. Highway 5) and had no significant effect on the daily mean and minimum dissolved-oxygen concentration. A third scenario evaluated the phosphorus loading into Fishing Creek Reservoir; four loading conditions of phosphorus into Catawba River were simulated. The four conditions included fully permitted and actual loading conditions, removal of all point sources from the Catawba River, and removal of all point and nonpoint sources from Sugar Creek. Removing the point-source inputs on the Catawba River and the point and nonpoint sources in Sugar Creek reduced the organic phosphorus and orthophosphate loadings to Fishing Creek Reservoir by 78 and 85 percent, respectively.

Climate Variability Impacts on Watershed Nutrient Delivery and Reservoir Production

NASA Astrophysics Data System (ADS)

White, J. D.; Prochnow, S. J.; Zygo, L. M.; Byars, B. W.

2005-05-01

Reservoirs in agricultural dominated watersheds tend to exhibit pulse-system behavior especially if located in climates dominated by summer convective precipitation inputs. Concentration and bulk mass of nutrient and sediment inputs into reservoir systems vary in terms of timing and magnitude of delivery from watershed sources to reservoirs under these climate conditions. Reservoir management often focuses on long-term average inputs without considering short and long-term impacts of variation in loading. In this study we modeled a watershed-reservoir system to assess how climate variability affects reservoir primary production through shifts in external loading and internal recycling of limiting nutrients. The Bosque watershed encompasses 423,824 ha in central Texas which delivers water to Lake Waco, a 2900 ha reservoir that is the primary water source for the city of Waco and surrounding areas. Utilizing the Soil Water Assessment Tool for the watershed and river simulations and the CE-Qual-2e model for the reservoir, hydrologic and nutrient dynamics were simulated for a 10 year period encompassing two ENSO cycles. The models were calibrated based on point measurement of water quality attributes for a two year time period. Results indicated that watershed delivery of nutrients was affected by the presence and density of small flood-control structure in the watershed. However, considerable nitrogen and phosphorus loadings were derived from soils in the upper watershed which have had long-term waste-application from concentrated animal feeding operations. During El Niño years, nutrient and sediment loads increased by 3 times above non-El Niño years. The simulated response within the reservoir to these nutrient and sediment loads had both direct and indirect. Productivity evaluated from chlorophyll a and algal biomass increased under El Niño conditions, however species composition shifts were found with an increase in cyanobacteria dominance. In non-El Niño years, species composition was more evenly distributed. At the longer time scale, El Niño events with accompanying increase in nutrient loads were followed by years in which productivity declined below levels predicted solely by nutrient ratios. This was due to subtle shifts in organic matter decomposition where productive years are followed by increases in refractory material which sequesters nutrients and reduces internal loading.

Digital data used to relate nutrient inputs to water quality in the Chesapeake Bay watershed, version 3.0

USGS Publications Warehouse

Brakebill, John W.; Preston, Stephen D.

2004-01-01

Chesapeake Bay restoration efforts are focused on improving water quality, living resources, and ecological habitats by 2010. One aspect of the water-quality restoration is the refinement of strategies designed to implement nutrient-reduction practices within the Bay watershed. These strategies are being refined and implemented by resource managers of the Chesapeake Bay Program (CBP), a partnership comprised of various Federal, State, and local agencies that includes jurisdictions within Delaware, Maryland, New York, Pennsylvania, Virginia, West Virginia, and the District of Columbia. The U.S. Geological Survey (USGS), an active member of the CBP, provides necessary water-quality information for these Chesapeake Bay nutrient-reduction strategy revisions and evaluations. The formulation and revision of effective nutrient-reduction strategies requires detailed scientific information and an analytical understanding of the sources, transport, and delivery of nutrients to the Chesapeake Bay. The USGS is supporting these strategies by providing scientific information to resource managers that can help them evaluate and understand these processes. One statistical model available to resource managers is a collection of SPAtially Referenced Regressions On Watershed (SPARROW) attributes, which uses a nonlinear regression approach to spatially relate nutrient sources and watershed characteristics to nutrient loads of streams throughout the Chesapeake Bay watershed. Developed by the USGS, information generated by SPARROW can help resource managers determine the geographical distribution and relative contribution of nutrient sources and the factors that affect their transport to the Bay. Nutrient source information representing the late 1990s time period was obtained from several agencies and used to create and compile digital spatial datasets of total nitrogen and total phosphorus contributions that served as input sources to the SPARROW models. These data represent atmospheric deposition, point-source locations, land-use, land-cover, and agricultural sources such as commercial fertilizer and manure applications. Watershed-characteristics datasets representing factors that affect the transport of nutrients also were compiled from previous applications of the SPARROW models in the Chesapeake Bay watershed. Datasets include average-annual precipitation and temperature, slope, soil permeability, and hydrogeomorphic regions. Nutrient-input and watershed-characteristics datasets representing conditions during the late 1990s were merged with a connected network of stream reaches and watersheds to provide the spatial detail required by SPARROW. Stream-nutrient load estimates for 125 sampling sites (87 for total nitrogen and 103 for total phosphorus) served as the dependent variables for the regressions, and were used to calibrate models of total nitrogen and total phosphorus depicting late 1990s conditions in the Chesapeake Bay watershed. Spatial data generated for the models can be used to identify the location of nutrient sources, while the models' nutrient estimates can be used to evaluate stream-nutrient load contributed locally by each source evaluated, the amount of local load generated that is transported to the Bay, and the factors that affect the nutrient transport. Applying the SPARROW methodology to late 1990s information completes three time periods (late 1980s, early 1990s, and late 1990s) of viable data that resource managers can use to evaluate the water-quality conditions within the Bay watershed in order to refine restoration goals and nutrient-reduction strategies.

Characterization and Placement of Wetlands for Integrated ...

EPA Pesticide Factsheets

Constructed wetlands have been recognized as an efficient and cost-effective conservation practice to protect water quality through reducing the transport of sediments and nutrients from upstream croplands to downstream water bodies. The challenge resides in targeting the strategic location of wetlands within agricultural watersheds to maximize the reduction in nutrient loads while minimizing their impact on crop production. Furthermore, agricultural watersheds involve complex interrelated processes requiring a systems approach to evaluate the inherent relationships between wetlands and multiple sediment/nutrient sources (sheet, rill, ephemeral gully, channels) and other conservation practices (filter strips). This study describes new capabilities of the USDA’s Annualized Agricultural Non-Point Source pollutant loading model, AnnAGNPS. A developed AnnAGNPS GIS-based wetland component, AgWet, is introduced to identify potential sites and characterize individual artificial or natural wetlands at a watershed scale. AgWet provides a simplified, semi-automated, and spatially distributed approach to quantitatively evaluate wetlands as potential conservation management alternatives. AgWet is integrated with other AnnAGNPS components providing seamless capabilities of estimating the potential sediment/nutrient reduction of individual wetlands. This technology provides conservationists the capability for improved management of watershed systems and support for nutrient

Estimating nitrogen loading and far-field dispersal potential from background sources and coastal finfish aquaculture: A simple framework and case study in Atlantic Canada

NASA Astrophysics Data System (ADS)

McIver, R.; Milewski, I.; Loucks, R.; Smith, R.

2018-05-01

Far-field nutrient impacts associated with finfish aquaculture have been identified as a topic of concern for regulators, managers, scientists, and the public for over two decades but disentangling aquaculture impacts from those caused by other natural and anthropogenic sources has impeded the development of monitoring metrics and management plans. We apply a bulk, steady-state nitrogen loading model (NLM) framework to estimate the annual input of Total Dissolved Nitrogen (TDN) from point and non-point sources to the watershed surrounding Port Mouton Bay, Nova Scotia (Canada). We then use the results of the NLM together with estimates of dissolved inorganic nitrogen (DIN) loading from a sea-cage trout farm in the Bay and progressive vector diagrams to illustrate potential patterns of DIN dispersal from the trout farm. Our estimated anthropogenic nitrogen contribution to Port Mouton Bay from all terrestrial and atmospheric sources is ∼211,703 kg TDN/year with atmospheric deposition accounting for almost all (98.6%). At a stocking level of ∼400,000 rainbow trout, the Port Mouton Bay sea-cage farm increases the annual anthropogenic TDN loading to the bay by 14.4% or 30,400 kg. Depending on current flow rates, nitrogen flux from the trout farm can be more than double the background concentrations of TDN near the farm site. Although it is unlikely that nitrogen loading from this single fish farm is saturating the DIN requirements of the entire bay, progressive vector diagrams suggest that the dispersal potential may be insufficient to mitigate potential symptoms of eutrophication associated with nitrogen fluxes. We present an accessible and user-friendly tool for managers to estimate baseline nutrient loading in relation to aquaculture and our use of progressive vector diagrams illustrate a practical and simple method for characterizing potential nutrient dispersal based on local conditions and spatial scales. Our study joins numerous studies which have highlighted the need for more effective monitoring and assessment methods to improve the detection of aquaculture effects at far-field scales and to assess those effects in relation to other natural and anthropogenic factors impacting coastal habitats.

Sources of nitrogen and phosphorus emissions to Irish rivers and coastal waters: Estimates from a nutrient load apportionment framework.

PubMed

Mockler, Eva M; Deakin, Jenny; Archbold, Marie; Gill, Laurence; Daly, Donal; Bruen, Michael

2017-12-01

More than half of surface water bodies in Europe are at less than good ecological status according to Water Framework Directive assessments, and diffuse pollution from agriculture remains a major, but not the only, cause of this poor performance. Agri-environmental policy and land management practices have, in many areas, reduced nutrient emissions to water. However, additional measures may be required in Ireland to further decouple the relationship between agricultural productivity and emissions to water, which is of vital importance given on-going agricultural intensification. The Source Load Apportionment Model (SLAM) framework characterises sources of phosphorus (P) and nitrogen (N) emissions to water at a range of scales from sub-catchment to national. The SLAM synthesises land use and physical characteristics to predict emissions from point (wastewater, industry discharges and septic tank systems) and diffuse sources (agriculture, forestry, etc.). The predicted annual nutrient emissions were assessed against monitoring data for 16 major river catchments covering 50% of the area of Ireland. At national scale, results indicate that total average annual emissions to surface water in Ireland are over 2700tyr -1 of P and 82,000tyr -1 of N. The proportional contributions from individual sources show that the main sources of P are from municipal wastewater treatment plants and agriculture, with wide variations across the country related to local anthropogenic pressures and the hydrogeological setting. Agriculture is the main source of N emissions to water across all regions of Ireland. These policy-relevant results synthesised large amounts of information in order to identify the dominant sources of nutrients at regional and local scales, contributing to the national nutrient risk assessment of Irish water bodies. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Nutrient Loadings to Streams of the Continental United States from Municipal and Industrial Effluent

USGS Publications Warehouse

Maupin, M.A.; Ivahnenko, T.

2011-01-01

Data from the United States Environmental Protection Agency Permit Compliance System national database were used to calculate annual total nitrogen (TN) and total phosphorus (TP) loads to surface waters from municipal and industrial facilities in six major regions of the United States for 1992, 1997, and 2002. Concentration and effluent flow data were examined for approximately 118,250 facilities in 45 states and the District of Columbia. Inconsistent and incomplete discharge locations, effluent flows, and effluent nutrient concentrations limited the use of these data for calculating nutrient loads. More concentrations were reported for major facilities, those discharging more than 1million gallons per day, than for minor facilities, and more concentrations were reported for TP than for TN. Analytical methods to check and improve the quality of the Permit Compliance System data were used. Annual loads were calculated using "typical pollutant concentrations" to supplement missing concentrations based on the type and size of facilities. Annual nutrient loads for over 26,600 facilities were calculated for at least one of the three years. Sewage systems represented 74% of all TN loads and 58% of all TP loads. This work represents an initial set of data to develop a comprehensive and consistent national database of point-source nutrient loads. These loads can be used to inform a wide range of water-quality management, watershed modeling, and research efforts at multiple scales. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

NAWQA, National Water-Quality Assessment Program; Allegheny-Monongahela River Basin

USGS Publications Warehouse

McAuley, Steven D.; Brown, Juliane B.; Sams, James I.

1997-01-01

Surface-water and ground-water quality and aquatic life can be significantly affected by the following principal issues identified in the Allegheny-Monongahela River Basin:Contaminants common to surface and under-ground coal mine discharge such as acidity, iron, aluminum, manganese, and sulfate.Volatile organic compounds (VOC’s), pesti-cides, and nutrients from increased urbanization.Runoff and loading of nutrients and pesticides to streams from nonpoint and point sources such as agricultural land uses.Radon in ground water.

Nutrient sources and transport in the Missouri River Basin, with emphasis on the effects of irrigation and reservoirs

USGS Publications Warehouse

Brown, J.B.; Sprague, L.A.; Dupree, J.A.

2011-01-01

SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were used to relate instream nutrient loads to sources and factors influencing the transport of nutrients in the Missouri River Basin. Agricultural inputs from fertilizer and manure were the largest nutrient sources throughout a large part of the basin, although atmospheric and urban inputs were important sources in some areas. Sediment mobilized from stream channels was a source of phosphorus in medium and larger streams. Irrigation on agricultural land was estimated to decrease the nitrogen load reaching the Mississippi River by as much as 17%, likely as a result of increased anoxia and denitrification in the soil zone. Approximately 16% of the nitrogen load and 33% of the phosphorus load that would have otherwise reached the Mississippi River was retained in reservoirs and lakes throughout the basin. Nearly half of the total attenuation occurred in the eight largest water bodies. Unlike the other major tributary basins, nearly the entire instream nutrient load leaving the outlet of the Platte and Kansas River subbasins reached the Mississippi River. Most of the larger reservoirs and lakes in the Platte River subbasin are upstream of the major sources, whereas in the Kansas River subbasin, most of the source inputs are in the southeast part of the subbasin where characteristics of the area and proximity to the Missouri River facilitate delivery of nutrients to the Mississippi River.

Nutrient Sources and Transport in the Missouri River Basin, with Emphasis on the Effects of Irrigation and Reservoirs1

PubMed Central

Brown, Juliane B; Sprague, Lori A; Dupree, Jean A

2011-01-01

Abstract SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were used to relate instream nutrient loads to sources and factors influencing the transport of nutrients in the Missouri River Basin. Agricultural inputs from fertilizer and manure were the largest nutrient sources throughout a large part of the basin, although atmospheric and urban inputs were important sources in some areas. Sediment mobilized from stream channels was a source of phosphorus in medium and larger streams. Irrigation on agricultural land was estimated to decrease the nitrogen load reaching the Mississippi River by as much as 17%, likely as a result of increased anoxia and denitrification in the soil zone. Approximately 16% of the nitrogen load and 33% of the phosphorus load that would have otherwise reached the Mississippi River was retained in reservoirs and lakes throughout the basin. Nearly half of the total attenuation occurred in the eight largest water bodies. Unlike the other major tributary basins, nearly the entire instream nutrient load leaving the outlet of the Platte and Kansas River subbasins reached the Mississippi River. Most of the larger reservoirs and lakes in the Platte River subbasin are upstream of the major sources, whereas in the Kansas River subbasin, most of the source inputs are in the southeast part of the subbasin where characteristics of the area and proximity to the Missouri River facilitate delivery of nutrients to the Mississippi River. PMID:22457581

Using SPARROW to Model Total Nitrogen Sources, and Transport in Rivers and Streams of California and Adjacent States, U.S.A

NASA Astrophysics Data System (ADS)

Saleh, D.; Domagalski, J. L.

2012-12-01

Sources and factors affecting the transport of total nitrogen are being evaluated for a study area that covers most of California and some areas in Oregon and Nevada, by using the SPARROW model (SPAtially Referenced Regression On Watershed attributes) developed by the U.S. Geological Survey. Mass loads of total nitrogen calculated for monitoring sites at stream gauging stations are regressed against land-use factors affecting nitrogen transport, including fertilizer use, recharge, atmospheric deposition, stream characteristics, and other factors to understand how total nitrogen is transported under average conditions. SPARROW models have been used successfully in other parts of the country to understand how nutrients are transported, and how management strategies can be formulated, such as with Total Maximum Daily Load (TMDL) assessments. Fertilizer use, atmospheric deposition, and climatic data were obtained for 2002, and loads for that year were calculated for monitored streams and point sources (mostly from wastewater treatment plants). The stream loads were calculated by using the adjusted maximum likelihood estimation method (AMLE). River discharge and nitrogen concentrations were de-trended in these calculations in order eliminate the effect of temporal changes on stream load. Effluent discharge information as well as total nitrogen concentrations from point sources were obtained from USEPA databases and from facility records. The model indicates that atmospheric deposition and fertilizer use account for a large percentage of the total nitrogen load in many of the larger watersheds throughout the study area. Point sources, on the other hand, are generally localized around large cities, are considered insignificant sources, and account for a small percentage of the total nitrogen loads throughout the study area.

Hindcasting of nutrient loadings from its catchment on a highly valuable coastal lagoon: the example of the Fleet, Dorset, UK, 1866–2004

PubMed Central

Weber, Geraint J; O'Sullivan, Patrick E; Brassley, Paul

2006-01-01

Background Nutrient loadings from its catchment upon The Fleet, a highly valuable coastal lagoon in Southern England, were hindcast for the period AD 1866–2004, using a catchment model, export coefficients, and historical data on land use changes, livestock numbers, and human population. Agriculture was the main nutrient source throughout, other inputs representing minor contributions. Permanent pasture was historically the main land use, with temporary grassland and cereals increasing during the mid-20th century. Sheep, the main 19th century livestock, were replaced by cattle during the 1930s. Results Total nitrogen loadings rose from ca 41 t yr-1 during the late 19th century to 49–54 t yr-1 for the mid-20th, increasing to 98 t yr-1 by 1986. Current values are ca 77 t yr-1. Total phosphorus loads increased from ca 0.75 t yr-1 for the late 19th century to ca 1.6 t yr-1 for the mid-20th, reached ca 2.2 t yr-1 in 1986, and are now ca 1.5 t yr-1. Loadings rose most rapidly between 1946 and 1988, owing to increased use of inorganic fertilisers, and rising sheep and cattle numbers. Livestock were the main nutrient source throughout, but inputs from inorganic fertilisers increased after 1946, peaking in 1986. Sewage treatment works and other sources contribute little nitrogen, but ca 35% of total phosphorus. Abbotsbury Swannery, an ancient Mute Swan community, provides ca 0.5% of total nitrogen, and ca 5% of total phosphorus inputs. Conclusion The Fleet has been grossly overloaded with nitrogen since 1866, climaxing during the 1980s. Total phosphorus inputs lay below 'permissible' limits until the 1980s, exceeding them in inner, less tidal parts of the lagoon, during the 1940s. Loadings on Abbotsbury Bay exceeded 'permissible' limits by the 1860s, becoming 'dangerous' during the mid-20th century. Phosphorus stripping at point sources will not significantly reduce loadings to all parts of the lagoon. Installation of 5 m buffer strips throughout the catchment and shoreline will marginally affect nitrogen loadings, but will reduce phosphorus inputs to the West Fleet below 'permissible' limits. Only a combination of measures will significantly affect Abbotsbury Bay, where, without effluent diversion, loadings will remain beyond 'permissible'. PMID:17196108

Lake Diefenbaker: Water Quality Assessment and Modeling for Management under Environmental Change

NASA Astrophysics Data System (ADS)

Sereda, J.; Wheater, H. S.; Hudson, J.; Doig, L.; Liber, K.; Jones, P.; Giesy, J.; Bharadwaj, L.

2011-12-01

Preliminary results are presented for a comprehensive inter-disciplinary study on Lake Diefenbaker initiated by the Global Institute for Water Security to understand the physical and biogeochemical processes affecting water quality under climate change and their policy implications. Lake Diefenbaker is a large reservoir (surface area ~500km2 and Zmean ~33m) located in Southern Saskatchewan, Canada and is a critically-important water resource for Saskatchewan. It receives nearly all of its flow from the South Saskatchewan River, which flows through some of the most urbanized and intense agricultural lands of southern Alberta. As a result these waters contain high levels of nutrients [nitrogen (N) and phosphorus (P)] along with a variety of chemical contaminants characteristic of anthropogenic activity. In addition, riparian and in-lake activities provide local sources of nutrients, from domestic sewage, agriculture and fish farming. The South Saskatchewan River has been identified by the World Wildlife Fund (2009) as Canada's most threatened river in terms of environmental flow. Lake Diefenbaker has numerous large deep embayments (depth >20m) and an annual water level fluctuation of ~6m. A deep thermocline (~25m) forms infrequently. Stratification does not occur throughout the lake. Anecdotal information suggests that the frequency and severity of algal blooms are increasing; although blooms have been sporadic and localized. This localized eutrophication may be related to local stratification patterns, point source nutrient loading, and/or internal lake processes (i.e., internal nutrient loading). A paleolimnological reconstruction has begun to assess historical nutrient and contaminant loading to Lake Diefenbaker and hence the trajectory of water quality in the lake. Major point sources and diffuse sources of N and P are also under investigation. In addition, the type (N versus P) and degree of nutrient limitation of bacteria and algae are being assessed (spatially and temporally). Concentrations of nutrients are heterogeneous throughout the lake. Preliminary results indicate that the degree and type of nutrient limitation, along with the cycling of phosphorus (uptake and regeneration) by plankton assemblages varies spatially and temporally. This information will be coupled with an understanding of the physical characteristics of the lake (i.e., mixing patterns) to explain the timing and distribution of algal blooms. A model will be developed to provide a platform for water and nutrient simulations to explore lake response to scenarios of climate and land use change, and the potential effects of local and regional management interventions. The research includes a community based participatory research program, which has involved key stakeholders in research definition and experimental design and ongoing discussion of research progress, and will include participation in management recommendations.

Ecosystem responses to long-term nutrient management in an urban estuary: Tampa Bay, Florida, USA

NASA Astrophysics Data System (ADS)

Greening, H.; Janicki, A.; Sherwood, E. T.; Pribble, R.; Johansson, J. O. R.

2014-12-01

In subtropical Tampa Bay, Florida, USA, we evaluated restoration trajectories before and after nutrient management strategies were implemented using long-term trends in nutrient loading, water quality, primary production, and seagrass extent. Following citizen demands for action, reduction in wastewater nutrient loading of approximately 90% in the late 1970s lowered external total nitrogen (TN) loading by more than 50% within three years. Continuing nutrient management actions from public and private sectors were associated with a steadily declining TN load rate and with concomitant reduction in chlorophyll-a concentrations and ambient nutrient concentrations since the mid-1980s, despite an increase of more than 1 M people living within the Tampa Bay metropolitan area. Water quality (chlorophyll-a concentration, water clarity as indicated by Secchi disk depth, total nitrogen concentration and dissolved oxygen) and seagrass coverage are approaching conditions observed in the 1950s, before the large increases in human population in the watershed. Following recovery from an extreme weather event in 1997-1998, water clarity increased significantly and seagrass is expanding at a rate significantly different than before the event, suggesting a feedback mechanism as observed in other systems. Key elements supporting the nutrient management strategy and concomitant ecosystem recovery in Tampa Bay include: 1) active community involvement, including agreement about quantifiable restoration goals; 2) regulatory and voluntary reduction in nutrient loadings from point, atmospheric, and nonpoint sources; 3) long-term water quality and seagrass extent monitoring; and 4) a commitment from public and private sectors to work together to attain restoration goals. A shift from a turbid, phytoplankton-based system to a clear water, seagrass-based system that began in the 1980s following comprehensive nutrient loading reductions has resulted in a present-day Tampa Bay which looks and functions much like it did in the relatively pre-disturbance 1950s period.

Modeling riverine nutrient transport to the Baltic Sea: a large-scale approach.

PubMed

Mörth, Carl-Magnus; Humborg, Christoph; Eriksson, Hanna; Danielsson, Asa; Medina, Miguel Rodriguez; Löfgren, Stefan; Swaney, Dennis P; Rahm, Lars

2007-04-01

We developed for the first time a catchment model simulating simultaneously the nutrient land-sea fluxes from all 105 major watersheds within the Baltic Sea drainage area. A consistent modeling approach to all these major watersheds, i.e., a consistent handling of water fluxes (hydrological simulations) and loading functions (emission data), will facilitate a comparison of riverine nutrient transport between Baltic Sea subbasins that differ substantially. Hot spots of riverine emissions, such as from the rivers Vistula, Oder, and Daugava or from the Danish coast, can be easily demonstrated and the comparison between these hot spots, and the relatively unperturbed rivers in the northern catchments show decisionmakers where remedial actions are most effective to improve the environmental state of the Baltic Sea, and, secondly, what percentage reduction of riverine nutrient loads is possible. The relative difference between measured and simulated fluxes during the validation period was generally small. The cumulative deviation (i.e., relative bias) [Sigma(Simulated - Measured)/Sigma Measured x 100 (%)] from monitored water and nutrient fluxes amounted to +8.2% for runoff, to -2.4% for dissolved inorganic nitrogen, to +5.1% for total nitrogen, to +13% for dissolved inorganic phosphorus and to +19% for total phosphorus. Moreover, the model suggests that point sources for total phosphorus compiled by existing pollution load compilations are underestimated because of inconsistencies in calculating effluent loads from municipalities.

Water quality assessment of the San Joaquin--Tulare basins, California; analysis of available data on nutrients and suspended sediment in surface water, 1972-1990

USGS Publications Warehouse

Kratzer, Charles R.; Shelton, Jennifer L.

1998-01-01

Nutrients and suspended sediment in surface water of the San Joaquin-Tulare basins in California were assessed using 1972-1990 data from the U.S. Geological Survey's National Water Information System and the U.S. Environmental Protection Agency's STOrage and RETrieval database. Loads of nutrients and suspended sediment were calculated at several sites and the contributions from point and nonpoint sources were estimated. Trends in nutrient and suspended-sediment concentrations were evaluated at several sites, especially at the basin outlet on the San Joaquin River. Comparisons of nutrient and suspended sediment concentrations were made among three environmental settings: the San Joaquin Valley--west side, the San Joaquin Valley--east side, and the Sierra Nevada.

Policy Guidance From a Multi-scale Suite of Natural Field and Digital Laboratories of Change: Hydrological Catchment Studies of Nutrient and Pollutant Source Releases, Waterborne Transport-Transformations and Mass Flows in Water Ecosystems

NASA Astrophysics Data System (ADS)

Destouni, G.

2008-12-01

Continental fresh water transports and loads excess nutrients and pollutants from various land surface sources, through the landscape, into downstream inland and coastal water environments. Our ability to understand, predict and control the eutrophication and the pollution pressures on inland, coastal and marine water ecosystems relies on our ability to quantify these mass flows. This paper synthesizes a series of hydro- biogeochemical studies of nutrient and pollutant sources, transport-transformations and mass flows in catchment areas across a range of scales, from continental, through regional and national, to individual drainage basin scales. Main findings on continental scales include correlations between country/catchment area, population and GDP and associated pollutant and nutrient loading, which differ significantly between world regions with different development levels. On regional scales, essential systematic near-coastal gaps are identified in the national monitoring of nutrient and pollutant loads from land to the sea. Combination of the unmonitored near-coastal area characteristics with the relevant regional nutrient and pollutant load correlations with these characteristics shows that the unmonitored nutrient and pollutant mass loads to the sea may often be as large as, or greater than the monitored river loads. Process studies on individual basin- scales show long-term nutrient and pollutant memories in the soil-groundwater systems of the basins, which may continue to uphold large mass loading to inland and coastal waters long time after mitigation of the sources. Linked hydro-biogeochemical-economic model studies finally demonstrate significant comparative advantages of policies that demand explicit quantitative account of the uncertainties implied by these monitoring gaps and long-term nutrient-pollution memories and time lags, and other knowledge, data and model limitations, instead of the now common neglect or subjective implicit handling of such uncertainties in strategies and practices for combating water pollution and eutrophication.

Prediction of phosphorus loads in an artificially drained lowland catchment using a modified SWAT model

NASA Astrophysics Data System (ADS)

Bauwe, Andreas; Eckhardt, Kai-Uwe; Lennartz, Bernd

2017-04-01

Eutrophication is still one of the main environmental problems in the Baltic Sea. Currently, agricultural diffuse sources constitute the major portion of phosphorus (P) fluxes to the Baltic Sea and have to be reduced to achieve the HELCOM targets and improve the ecological status. Eco-hydrological models are suitable tools to identify sources of nutrients and possible measures aiming at reducing nutrient loads into surface waters. In this study, the Soil and Water Assessment Tool (SWAT) was applied to the Warnow river basin (3300 km2), the second largest watershed in Germany discharging into the Baltic Sea. The Warnow river basin is located in northeastern Germany and characterized by lowlands with a high proportion of artificially drained areas. The aim of this study were (i) to estimate P loadings for individual flow fractions (point sources, surface runoff, tile flow, groundwater flow), spatially distributed on sub-basin scale. Since the official version of SWAT does not allow for the modeling of P in tile drains, we tested (ii) two different approaches of simulating P in tile drains by changing the SWAT source code. The SWAT source code was modified so that (i) the soluble P concentration of the groundwater was transferred to the tile water and (ii) the soluble P in the soil was transferred to the tiles. The SWAT model was first calibrated (2002-2011) and validated (1992-2001) for stream flow at 7 headwater catchments at a daily time scale. Based on this, the stream flow at the outlet of the Warnow river basin was simulated. Performance statistics indicated at least satisfactory model results for each sub-basin. Breaking down the discharge into flow constituents, it becomes visible that stream flow is mainly governed by groundwater and tile flow. Due to the topographic situation with gentle slopes, surface runoff played only a minor role. Results further indicate that the prediction of soluble P loads was improved by the modified SWAT versions. Major sources of P in rivers are groundwater and tile flow. P was also released by surface runoff during large storm events when sediment was eroded into the rivers. The contributions of point sources in terms of waste water treatment plants to the overall P loading were low. The modifications made in the SWAT source code should be considered as a starting point to simulate P loads in artificially drained landscapes more precisely. Further testing and development of the code is required.

Environmental response of an Irish estuary to changing land management practices.

PubMed

Ní Longphuirt, Sorcha; O'Boyle, Shane; Stengel, Dagmar Brigitte

2015-07-15

Anthropogenic pressures have led to problems of nutrient over-enrichment and eutrophication in estuarine and coastal systems on a global scale. Recent improvements in farming practices, specifically a decrease in fertiliser application rates, have reduced nutrient loadings in Ireland. In line with national and European Directives, monitoring of Irish estuarine systems has been conducted for the last 30years, allowing a comparison of the effectiveness of measures undertaken to improve water quality and chemical and biological trends. The Blackwater Estuary, which drains a large agricultural catchment on the south coast of Ireland, has experienced a decrease in calculated nitrogen (N) (17%) and phosphorus (P) (20%) loads in the last decade. Monitored long-term river inputs reflect the reductions while estuarine P concentrations, chlorophyll and dissolved oxygen saturation show concurrent improvement. Consistently high N concentrations suggest a decoupling between N loads and estuarine responses. This highlights the complex interaction between N and P load reductions, and biochemical processes relating to remineralisation and primary production which can alter the effectiveness of the estuarine filter in reducing nutrient transport to the coastal zone. Effective management and reduction of both diffuse and point nutrient sources to surface waters require a consideration of the processes which may alter the effectiveness of measures in estuarine and coastal waters. Copyright © 2015. Published by Elsevier B.V.

Forecasting future phosphorus export to the Laurentian Great Lakes from land-derived nutrient inputs

NASA Astrophysics Data System (ADS)

LaBeau, M. B.; Robertson, D. M.; Mayer, A. S.; Pijanowski, B. C.

2011-12-01

Anthropogenic use of the land through agricultural and urban activities has significantly increased phosphorus loading to rivers that flow to the Great Lakes. Phosphorus (P) is a critical element in the eutrophication of the freshwater ecosystems, most notably the Great Lakes. To better understand factors influencing phosphorus delivery to aquatic systems and thus their potential harmful effects to lake ecosystems, models that predict P export should incorporate account for changing changes in anthropogenic activities. Land-derived P from high yielding sources, such as agriculture and urban areas, affect eutrophication at various scales (e.g. specific bays to all of Lake Erie). SPARROW (SPAtially Referenced Regression On Watershed attributes) is a spatially explicit watershed model that has been used to understand linkages between land-derived sources and nutrient transport to the Great Lakes. The Great Lakes region is expected to experience a doubling of urbanized areas along with a ten percent increase in agricultural use over the next 40 years, which is likely to increase P loading. To determine how these changes will impact P loading, SPARROW have been developed that relate changes in land use to changes in nutrient sources, including relationships between row crop acreage and fertilizer intensity and urban land use and point source intensity. We used land use projections from the Land Transformation Model, a, spatially explicit, neural-net based land change model. Land use patterns from current to 2040 were used as input into HydroSPARROW, a forecasting tool that enables SPARROW to simulate the effects of various land-use and climate scenarios. Consequently, this work is focusing on understanding the effects of how specific agriculture and urbanization activities affect P loading in the watersheds of the Laurentian Great Lakes to potentially find strategies to reduce the extent and severity of future eutrophication.

Using Soluble Reactive Phosphorus and Ammonia to Identify Point Source Discharge from Large Livestock Facilities

NASA Astrophysics Data System (ADS)

Borrello, M. C.; Scribner, M.; Chessin, K.

2013-12-01

A growing body of research draws attention to the negative environmental impacts on surface water from large livestock facilities. These impacts are mostly in the form of excessive nutrient loading resulting in significantly decreased oxygen levels. Over-application of animal waste on fields as well as direct discharge into surface water from facilities themselves has been identified as the main contributor to the development of hypoxic zones in Lake Erie, Chesapeake Bay and the Gulf of Mexico. Some regulators claim enforcement of water quality laws is problematic because of the nature and pervasiveness of non-point source impacts. Any direct discharge by a facility is a violation of permits governed by the Clean Water Act, unless the facility has special dispensation for discharge. Previous research by the principal author and others has shown runoff and underdrain transport are the main mechanisms by which nutrients enter surface water. This study utilized previous work to determine if the effects of non-point source discharge can be distinguished from direct (point-source) discharge using simple nutrient analysis and dissolved oxygen (DO) parameters. Nutrient and DO parameters were measured from three sites: 1. A stream adjacent to a field receiving manure, upstream of a large livestock facility with a history of direct discharge, 2. The same stream downstream of the facility and 3. A stream in an area relatively unimpacted by large-scale agriculture (control site). Results show that calculating a simple Pearson correlation coefficient (r) of soluble reactive phosphorus (SRP) and ammonia over time as well as temperature and DO, distinguishes non-point source from point source discharge into surface water. The r value for SRP and ammonia for the upstream site was 0.01 while the r value for the downstream site was 0.92. The control site had an r value of 0.20. Likewise, r values were calculated on temperature and DO for each site. High negative correlations between temperature and DO are indicative of a relatively unimpacted stream. Results from this study are commensurate with nutrient correlations and are: r = -0.97 for the upstream site, r = -0.21 for the downstream site and r = -0.89 for the control site. Results from every site tested were statistically significant (p ≤ 0.05). These results support previous studies and demonstrate that the simple analytical techniques mentioned provide an effective means for regulatory agencies and community groups to monitor and identify point source discharge from large livestock facilities.

The Effects of Groundwater-associated Nutrients on Benthic Community Composition in Maunalua Bay, Hawaíi

NASA Astrophysics Data System (ADS)

La Valle, F. F.; Thomas, F. I. M.

2016-02-01

As populations grow and development efforts continue in coastal regions throughout the world, eutrophication is one of the leading issues surrounding coastal ecosystems. Currently, studies on subterranean groundwater discharge (SGD) are confirming that SGD can contain substantial nutrient concentrations due to agricultural activities, urbanization, leaky septic and sewer systems, and use of fertilizers. Thus, it is important for SGD with high nutrient concentrations to be monitored for its impact on coastal dynamics. Coral reef systems are especially sensitive to changes in nutrient concentrations which can change community composition by creating advantageous biochemical environments for specific algal species. Excess nutrients along with decreased herbivory have been attributed to phase shifts from coral dominated to algal dominated reefs. In this study we mapped algal cover and nutrient load with respect to the groundwater in two fringing reefs (Black Point and Wailupe) in Maunalua Bay, Oahu, Hawaíi. We established relationships between salinity and nutrient concentrations for the two sites by sampling synoptically on an onshore to offshore transect from the SGD seeps (n = 48 Black Point, n = 40 Wailupe, R2 > 0.965). The groundwater end members at the two sites have different nutrient signatures: concentrations at Black Point averaged 167.3 uM N+N (NO3- + NO2-) and 3.57 uM PO43-, while at Wailupe nutrient concentrations averaged 68.7 uM N+N and 1.96 uM PO43-. We used these relationships to calculate nutrient time series after deploying 23 autonomous salinity sensors for one month across the benthos at each site respectively. Benthic surveys taken over 2 seasons indicate that the algal composition and distribution relative to the groundwater sources differ at the two sites. Growth rates of some major macroalgal species also differ with distance from SGD source. Further studies on the biological effects of high SGD-associated nutrients on coastal systems are warranted.

Estimates of long-term mean-annual nutrient loads considered for use in SPARROW models of the Midcontinental region of Canada and the United States, 2002 base year

USGS Publications Warehouse

Saad, David A.; Benoy, Glenn A.; Robertson, Dale M.

2018-05-11

Streamflow and nutrient concentration data needed to compute nitrogen and phosphorus loads were compiled from Federal, State, Provincial, and local agency databases and also from selected university databases. The nitrogen and phosphorus loads are necessary inputs to Spatially Referenced Regressions on Watershed Attributes (SPARROW) models. SPARROW models are a way to estimate the distribution, sources, and transport of nutrients in streams throughout the Midcontinental region of Canada and the United States. After screening the data, approximately 1,500 sites sampled by 34 agencies were identified as having suitable data for calculating the long-term mean-annual nutrient loads required for SPARROW model calibration. These final sites represent a wide range in watershed sizes, types of nutrient sources, and land-use and watershed characteristics in the Midcontinental region of Canada and the United States.

A smart market for nutrient credit trading to incentivize wetland construction

NASA Astrophysics Data System (ADS)

Raffensperger, John F.; Prabodanie, R. A. Ranga; Kostel, Jill A.

2017-03-01

Nutrient trading and constructed wetlands are widely discussed solutions to reduce nutrient pollution. Nutrient markets usually include agricultural nonpoint sources and municipal and industrial point sources, but these markets rarely include investors who construct wetlands to sell nutrient reduction credits. We propose a new market design for trading nutrient credits, with both point source and non-point source traders, explicitly incorporating the option of landowners to build nutrient removal wetlands. The proposed trading program is designed as a smart market with centralized clearing, done with an optimization. The market design addresses the varying impacts of runoff over space and time, and the lumpiness of wetland investments. We simulated the market for the Big Bureau Creek watershed in north-central Illinois. We found that the proposed smart market would incentivize wetland construction by assuring reasonable payments for the ecosystem services provided. The proposed market mechanism selects wetland locations strategically taking into account both the cost and nutrient removal efficiencies. The centralized market produces locational prices that would incentivize farmers to reduce nutrients, which is voluntary. As we illustrate, wetland builders' participation in nutrient trading would enable the point sources and environmental organizations to buy low cost nutrient credits.

Retrofitting impervious urban infrastructure with green technology for rainfall-runoff restoration, indirect reuse and pollution load reduction.

PubMed

Sansalone, John; Raje, Saurabh; Kertesz, Ruben; Maccarone, Kerrilynn; Seltzer, Karl; Siminari, Michele; Simms, Peter; Wood, Brandon

2013-12-01

The built environs alter hydrology and water resource chemistry. Florida is subject to nutrient criteria and is promulgating "no-net-load-increase" criteria for runoff and constituents (nutrients and particulate matter, PM). With such criteria, green infrastructure, hydrologic restoration, indirect reuse and source control are potential design solutions. The study simulates runoff and constituent load control through urban source area re-design to provide long-term "no-net-load-increases". A long-term continuous simulation of pre- and post-development response for an existing surface parking facility is quantified. Retrofits include a biofiltration area reactor (BAR) for hydrologic and denitrification control. A linear infiltration reactor (LIR) of cementitious permeable pavement (CPP) provides infiltration, adsorption and filtration. Pavement cleaning provided source control. Simulation of climate and source area data indicates re-design achieves "no-net-load-increases" at lower costs compared to standard construction. The retrofit system yields lower cost per nutrient load treated compared to Best Management Practices (BMPs). Copyright © 2013 Elsevier Ltd. All rights reserved.

Monitoring Stream Nutrient Concentration Trends in a Mixed-Land-Use Watershed

NASA Astrophysics Data System (ADS)

Zeiger, S. J.; Hubbart, J. A.

2014-12-01

Mixed-land use watersheds are often a complex patchwork of forested, agricultural, and urban land-uses where differential land-use mediated non-point source pollution can significantly impact water quality. Stream nitrogen and phosphorus concentrations serve as important variables for quantifying land use effects on non-point source pollution in receiving waters and relative impacts on aquatic biota. The Hinkson Creek Watershed (HCW) is a representative mixed land use urbanizing catchment (231 km2) located in central Missouri, USA. A nested-scale experimental watershed study including five permanent hydroclimate stations was established in 2009 to provide quantitative understanding of multiple land use impacts on nutrient loading. Spectrophotometric analysis was used to quantify total inorganic nitrogen (TIN) and total phosphorus (TP as PO4) regimes. Results (2010 - 2013) indicate average nitrate (NO3-) concentration (mg/l) range of 0.28 to 0.46 mg/l, nitrite (NO2-) range of 0.02 to 0.03 mg/l, ammonia (NH3) ranged from 0.04 to 0.08 mg/l, and TP range of 0.26 to 0.39 mg/l. With n=858, NO3-, NO2-, NH3, and TP concentrations were significantly (CI=95%, p=0.00) higher in the subbasin with the greatest percent cumulative agricultural land use (57%). NH3 and TP concentrations were significantly (CI=95%, p=0.00) higher (with the exception of the agricultural subbasin) in the subbasin with the greatest percent cumulative urban land use (26%). Results from multiple regression analyses showed percent cumulative agricultural and urban land uses accounted for 85% and 96% of the explained variance in TIN loading (CI=95%, p=0.08) and TP loading (CI=95%, p=0.02), respectively, between gauging sites. These results improve understanding of agricultural and urban land use impacts on nutrient concentrations in mixed use watersheds of the Midwest and have implications for nutrient reduction programs in the Mississippi River Basin and hypoxia reductions in the Gulf of Mexico, USA.

Characterization of nutrient, organic carbon, and sediment loads and concentrations from the Mississippi River into the northern Gulf of Mexico

USGS Publications Warehouse

Turner, R.E.; Rabalais, N.N.; Alexander, Richard B.; McIsaac, G.; Howarth, R.W.

2007-01-01

We synthesize and update the science supporting the Action Plan for Reducing, Mitigating, and Controlling Hypoxia in the Northern Gulf of Mexico (Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2001) with a focus on the spatial and temporal discharge and patterns of nutrient and organic carbon delivery to the northern Gulf of Mexico, including data through 2006. The discharge of the Mississippi River watershed over 200 years varies but is not demonstrably increasing or decreasing. About 30% of the Mississippi River was shunted westward to form the Atchafalaya River, which redistributed water and nutrient loads on the shelf. Data on nitrogen concentrations from the early 1900s demonstrate that the seasonal and annual concentrations in the lower river have increased considerably since then, including a higher spring loading, following the increase in fertilizer applications after World WarII. The loading of total nitrogen (TN) fell from 1990 to 2006, but the loading of total phosphorus (TP) has risen slightly, resulting in a decline in the TN:TP ratios. The present TN:TP ratios hover around an average indicative of potential nitrogen limitation on phytoplankton growth, or balanced growth limitation, but not phosphorus limitation. The dissolved nitrogen:dissolved silicate ratios are near the Redfield ratio indicative of growth limitations on diatoms. Although nutrient concentrations are relatively high compared to those in many other large rivers, the water quality in the Mississippi River is not unique in that nutrient loads can be described by a variety of land-use models. There is no net removal of nitrogen from water flowing through the Atchafalaya basin, but the concentrations of TP and suspended sediments are lower at the exit point (Morgan City, Louisiana) than in the water entering the Atchafalaya basin. The removal of nutrients entering offshore waters through diversion of river water into wetlands is presently less than 1% of the total loadings going directly offshore, and would be less than 8% if the 10,093 km2 of coastal wetlands were successfully engineered for that purpose. Wetland loss is an insignificant contribution to the carbon loading offshore, compared to in situ marine production. The science-based conclusions in the Action Plan about nutrient loads and sources to the hypoxic zone off Louisiana are sustained by research and monitoring occurring in the subsequent 10 years.

Nutrient Status and Criteria Development for the Saint John River, Canada, Using a Weight of Evidence Approach

NASA Astrophysics Data System (ADS)

Culp, J. M.; Luiker, E. A.; Noel, L.; Curry, A. R.; Hryn, D.; Heard, K.

2005-05-01

The Saint John River is the largest in Maine/New Brunswick (673 km in length, draining 55,000 km2) with a history of natural resource use and nutrient effluent release to the watershed since the late 17th century. Our objective was to obtain a basic understanding of the contemporary nutrient conditions of the non-tidal portion of the river in relation to historical conditions, and to consider how the contemporary river is affected by point and non-point source nutrient loadings. The study included review of historical provincial and federal water quality databases dating back to the 1960s. Current water quality monitoring programs have focused on nitrogen (nitrite, nitrate, ammonia, TKN), phosphorus (total, dissolved, and soluble reactive phosphorus), DIC/DOC, and biomass of periphyton and phytoplankton. To determine nutrient limitation, nutrient diffusing substrate studies were conducted in river reaches of known nutrient enrichment. Oxygen stable isotopes were also used to provide information on the photosynthesis to respiration ratio. A weight of evidence approach combining the results of these studies was used to determine trophic status of river reaches and to highlight areas of eutrophication. From this information nutrient criteria for the Saint John River will be proposed.

Simulation of dissolved nutrient export from the Dongjiang river basin with a grid-based NEWS model

NASA Astrophysics Data System (ADS)

Rong, Qiangqiang; Su, Meirong; Yang, Zhifeng; Cai, Yanpeng; Yue, Wencong; Dang, Zhi

2018-06-01

In this research, a grid-based NEWS model was proposed through coupling the geographic information system (GIS) with the Global NEWS model framework. The model was then applied to the Dongjiang River basin to simulate the dissolved nutrient export from this area. The model results showed that the total amounts of the dissolved nitrogen and phosphorus exported from the Dongjiang River basin were approximately 27154.87 and 1389.33 t, respectively. 90 % of the two loads were inorganic forms (i.e. dissolved inorganic nitrogen and phosphorus, DIN and DIP). Also, the nutrient export loads did not evenly distributed in the basin. The main stream watershed of the Dongjiang River basin has the largest DIN and DIP export loads, while the largest dissolved organic nitrogen and phosphorus (DON and DOP) loads were observed in the middle and upper stream watersheds of the basin, respectively. As for the nutrient exported from each subbasin, different sources had different influences on the output of each nutrient form. For the DIN load in each subbasin, fertilization application, atmospheric deposition and biological fixation were the three main contributors, while eluviation was the most important source for DON. In terms of DIP load, fertilizer application and breeding wastewater were the main contributors, while eluviation and fertilizer application were the two main sources for DOP.

What does atmospheric nitrogen contribute to the Gulf of Mexico area of oxygen depletion?

NASA Astrophysics Data System (ADS)

Rabalais, N. N.

2017-12-01

The northern Gulf of Mexico influenced by the freshwater discharge and nutrient loads of the Mississippi River watershed is the location of the world's second largest human-caused area of coastal hypoxia. Over 500 more anthropogenic `dead zones' exist in coastal waters. The point source inputs within the Mississippi River watershed account for about ten per cent of the total nitrogen inputs to the Mississippi River, with the remaining being nonpoint source. Atmospheric nitrogen makes up about sixteen per cent of the nonpoint source input of nitrogen. Most of the NOx is generated within the Ohio River watershed from the burning of fossil fuels. Some remains to be deposited into the same watershed, but the airshed deposits much of the NOx along the U.S. eastern seaboard, including Chesapeake Bay, which also has a hypoxia problem. Most of the volatilized ammonia is produced from fertilizers or manure within the upper Mississippi River watershed, is deposited within a localized airshed, and is not airborne long distances like the NOx. The atmospheric nitrogen input to the coastal waters affected by hypoxia is considered to be minimal. In the last half century, the nitrogen load from the Mississippi River to the Gulf of Mexico has increased 300 percent. During this period, low oxygen bottom-waters have developed in the coastal waters and worsened coincident with the increase in the nitrogen load. The 31-yr average size of the bottom-water hypoxia area in the Gulf of Mexico is 13,800 square kilometers, well over the 5,000 square kilometers goal of the Mississippi River Nutrient/Gulf of Mexico Hypoxia Task Force. Knowing the amounts and sources of excess nutrients to watersheds with adjacent coastal waters experiencing eutrophication and hypoxia is important in the management strategies to reduce those nutrients and improve water quality.

Hydrology and water quality of forested lands in eastern North Carolina

Treesearch

G.M. Chescheir; M.E. Lebo; D.M. Amatya; J. Hughes; J.W. Gilliam; R.W. Skaggs; R.B. Herrmann

2003-01-01

Nonpoint sources of nutrients (NPS) are a widespread source of surface water pollution throu&out the United States. Characterizing the sources of this NPS nutrient loading is challenging due to variation in land management practices, physioyaphic setting, site conditions such as soil type, and climatic variation. For nutrients, there is the added challenge of...

ENERGY AND NUTRIENT EXTRACTION FROM ONSITE WASTEWATER - PHASE I

EPA Science Inventory

Onsite wastewater systems are a significant source of nutrient loading to the environment and there is a demand for technologies that remove nutrients at the source. Most desired are passive, low-...

ROLE OF OCEANIC AND RIVERINE SOURCES IN NUTRIENT AND PHYTOPLANKTON DYNAMICS IN YAQUINA BAY, OREGON

EPA Science Inventory

There is evidence that coastal ecosystems are experiencing environmental problems due to excess nutrients. The numerous sources, forms, and pathways of nutrients make it difficult to determine the effect of increases in anthropogenic loading. This is particularly evident in Pac...

Study of nonpoint source nutrient loading in the Patuxent River basin, Maryland

USGS Publications Warehouse

Preston, S.D.

1997-01-01

Study of nonpoint-source (NPS) nutrient loading in Maryland has focused on the Patuxent watershed because of its importance and representativeness of conditions in the State. Evaluation of NPS nutrient loading has been comprehensive and has included long-term monitoring, detailed watershed modeling, and synoptic sampling studies. A large amount of information has been compiled for the watershed and that information is being used to identify primary controls and efficient management strategies for NPS nutrient loading. Results of the Patuxent NPS study have identified spatial trends in water quality that appear to be related to basin charcteristics such as land use, physiography, andgeology. Evaluation of the data compiled by the study components is continuing and is expected to provide more detailed assessments of the reasons for spatial trends. In particular, ongoing evaluation of the watershed model output is expected to provide detailed information on the relative importance of nutrient sources and transport pathways across the entire watershed. Planned future directions of NPS evaluation in the State of Maryland include continued study of water quality in the Patuxent watershed and a shift in emphasis to a statewide approach. Eventually, the statewide approach will become the primary approach usedby the State to evaluate NPS loading. The information gained in the Patuxent study and the tools developed will represent valuable assets indeveloping the statewide NPS assessment program.

Modeling Nutrient Release in the Tai Lake Basin of China: Source Identification and Policy Implications

NASA Astrophysics Data System (ADS)

Liu, Beibei; Liu, Heng; Zhang, Bing; Bi, Jun

2013-03-01

Because nutrient enrichment has become increasingly severe in the Tai Lake Basin of China, identifying sources and loads is crucial for watershed nutrient management. This paper develops an empirical framework to estimate nutrient release from five major sectors, which requires fewer input parameters and produces acceptable accuracy. Sectors included are industrial manufacturing, livestock breeding (industrial and family scale), crop agriculture, household consumption (urban and rural), and atmospheric deposition. Results show that in the basin (only the five sectors above), total nutrient loads of nitrogen (N) and phosphorus (P) into aquatic systems in 2008 were 33043.2 tons N a-1 and 5254.4 tons P a-1, and annual area-specific nutrient loads were 1.94 tons N km-2 and 0.31 tons P km-2. Household consumption was the major sector having the greatest impact (46 % in N load, 47 % in P load), whereas atmospheric deposition (18 %) and crop agriculture (15 %) sectors represented other significant proportions of N load. The load estimates also indicate that 32 % of total P came from the livestock breeding sector, making it the second largest phosphorus contributor. According to the nutrient pollution sectors, six best management practices are selected for cost-effectiveness analysis, and feasible options are recommended. Overall, biogas digester construction on industrial-scale farms is proven the most cost-effective, whereas the building of rural decentralized facilities is the best alternative under extreme financial constraint. However, the reduction potential, average monetary cost, and other factors such as risk tolerance of policy makers should all be considered in the actual decision-making process.

Elkhorn Slough: Detecting Eutrophication through Geospatial Modeling Applications

NASA Astrophysics Data System (ADS)

Caraballo Álvarez, I. O.; Childs, A.; Jurich, K.

2016-12-01

Elkhorn Slough in Monterey, California, has experienced substantial nutrient loading and eutrophication over the past 21 years as a result of fertilizer-rich runoff from nearby agricultural fields. This study seeks to identify and track spatial patterns of eutrophication hotspots and the correlation to land use changes, possible nutrient sources, and general climatic trends using remotely sensed and in situ data. Threats of rising sea level, subsiding marshes, and increased eutrophication hotspots demonstrate the necessity to analyze the effects of increasing nutrient loads, relative sea level changes, and sedimentation within Elkhorn Slough. The Soil & Water Assessment Tool (SWAT) model integrates specified inputs to assess nutrient and sediment loading and their sources. TerrSet's Land Change Modeler forecasts the future potential of land change transitions for various land cover classes around the slough as a result of nutrient loading, eutrophication, and increased sedimentation. TerrSet's Earth Trends Modeler provides a comprehensive analysis of image time series to rapidly assess long term eutrophication trends and detect spatial patterns of known hotspots. Results from this study will inform future coastal management practices and provide greater spatial and temporal insight into Elkhorn Slough eutrophication dynamics.

Proximate and Ultimate Limiting Nutrients in the Mississippi River Plume: Implications for Hypoxia Reduction Through Nutrient Management

NASA Astrophysics Data System (ADS)

Fennel, K.; Laurent, A.

2016-02-01

A large hypoxic area (15,000 km2 on average) forms every summer over the Texas-Louisiana shelf in the northern Gulf of Mexico due to decay of organic matter that is primarily derived from nutrient inputs from the Mississippi/Atchafalaya River System. Efforts are underway to reduce the extent of hypoxic conditions through nutrient management in the watershed; for example, an interagency Hypoxia Task Force is developing Action Plans with input from various stakeholders that set out targets for hypoxia reduction. An open question is by how much nutrient loads would have to be decreased in order to produce the desired reductions in hypoxia and when these would be measurable over natural variability. We have performed a large number of multi-year nutrient load reduction scenarios with a regional biogeochemical model for the region. The model is based on the Regional Ocean Modeling System (ROMS), explicitly includes nitrogen (N) and phosphorus (P) species as inorganic nutrients, and has been shown to realistically reproduce the key processes responsible for hypoxia generation. We have quantified the effects of differential reductions in river N and P loads on hypoxic extent. An assessment of the effects of N versus P reductions is important because, thus far, nutrient management efforts have focused on N, yet P is known to limit primary production in spring and early summer. A debate is ongoing as to whether targets for P reductions should be set and whether nutrient reduction efforts should focus solely on P, which results primarily from urban and industrial point sources and is uncoupled from agricultural fertilizer application. Our results strongly indicate that N is the `ultimate' limiting nutrient to primary production determining the areal extent and duration of hypoxic conditions in a cumulative sense, while P is temporarily limiting in spring. Although reductions in river P load would decrease hypoxic extent in early summer, they would have a much smaller effect than N reductions on the cumulative extent and duration of hypoxic conditions. Combined reductions of N and P have the greatest effect.

Proximate versus ultimate limiting nutrients in the Mississippi River Plume and Implications for Hypoxia Reductions through Nutrient Management

NASA Astrophysics Data System (ADS)

Fennel, Katja; Laurent, Arnaud

2016-04-01

A large hypoxic area (15,000 km2 on average) forms every summer over the Texas-Louisiana shelf in the northern Gulf of Mexico due to decay of organic matter that is primarily derived from nutrient inputs from the Mississippi/Atchafalaya River System. Efforts are underway to reduce the extent of hypoxic conditions through nutrient management in the watershed; for example, an interagency Hypoxia Task Force is developing Action Plans with input from various stakeholders that set out targets for hypoxia reduction. An open question is how far nutrient loads would have to be decreased in order to produce the desired reductions in hypoxia and when these would be measurable given significant natural variability. We have simulated a large number of multi-year nutrient load reduction scenarios with a regional biogeochemical model for the region. The model is based on the Regional Ocean Modeling System (ROMS), explicitly includes nitrogen (N) and phosphorus (P) species as inorganic nutrients, and has been shown to realistically reproduce the key processes responsible for hypoxia generation. We have quantified the effects of differential reductions in river N and P loads on hypoxic extent. An assessment of the effects of N versus P reductions is important because, thus far, nutrient management efforts have focused on N, yet P is known to limit primary production in spring and early summer. A debate is ongoing as to whether targets for P reductions should be set and whether nutrient reduction efforts should focus solely on P, which results primarily from urban and industrial point sources and is uncoupled from agricultural fertilizer application. Our results strongly indicate that N is the 'ultimate' limiting nutrient to primary production determining the areal extent and duration of hypoxic conditions in a cumulative sense, while P is temporarily limiting in spring. Although reductions in river P load would decrease hypoxic extent in early summer, they would have a much smaller effect than N reductions on the cumulative extent and duration of hypoxic conditions. Combined reductions of N and P have the greatest effect.

Methodology for estimating nutrient loads discharged from the east coast canals to Biscayne Bay, Miami-Dade County, Florida

USGS Publications Warehouse

Lietz, Arthur C.

1999-01-01

Biscayne Bay is an oligotrophic, subtropical estuary located along the southeastern coast of Florida that provides habitat for a variety of plant and animal life. Concern has arisen with regard to the ecological health of Biscayne Bay because of the presence of nutrient-laden discharges from the east coast canals that drain into the bay. This concern, as well as planned diversion of discharges for ecosystem restoration from the urban and agricultural corridors of Miami-Dade County to Everglades National Park, served as the impetus for a study conducted during the 1996 and 1997 water years to estimate nutrient loads discharged from the east coast canals into Biscayne Bay. Analytical results indicated that the highest concentration of any individual nutrient sampled for in the study was 4.38 mg/L (milligrams per liter) for nitrate at one site, and the lowest concentrations determined were below the detection limits for orthophosphate at six sites and nitrite at four sites. Median concentrations for all the sites were 0.75 mg/L for total organic nitrogen, 0.10 mg/L for ammonia, 0.02 mg/L for nitrite, 0.18 mg/L for nitrate, 0.20 mg/L for nitrite plus nitrate nitrogen, 0.02 mg/L for total phosphorus, and 0.005 mg/L for orthophosphate. The maximum total phosphorus concentration of 0.31 mg/L was the only nutrient concentration to exceed U.S. Environmental Protection Agency (1986) water-quality criteria. High concentrations of total phosphorus usually reflect contamination as a result of human activities. Five sites exceeded the fresh-water quality standard of 0.5 mg/L for ammonia concentration as determined by the Miami-Dade County Department of Environmental Resources Management. Median total organic nitrogen concentrations were higher in urban and forested/wetland areas than in agricultural areas; median concentrations of nitrite, nitrate, and nitrite plus nitrate nitrogen were higher in agricultural areas than in urban and forested/wetland areas; and ammonia, total phosphorus, and orthophosphate concentrations were higher in urban areas than in agricultural and forested/wetland areas. These results coincide with expected differences in nutrient concentrations based on knowledge of point and nonpoint source influences and nutrient cycling. The Wilcoxon signed ranks test (WSRT) was used to compare differences between point (grab) samples and depth-integrated samples for total nitrogen and total phosphorus concentrations at 12 east coast canal sites. Statistically significant differences (alpha level of 0.025) in total phosphorus concentrations between point (grab) samples collected 1.0 meter deep and depth-integrated samples were detected at three sites. One site also showed statistically significant differences in total phosphorus concentrations between point (grab) samples collected 0.5 meter deep and depth-integrated samples. There were no statistically significant differences in total nitrogen and total phosphorus concentrations between point (grab) samples collected 0.5 meter deep and 1.0 meter deep for all the sites. Results of the line of organic correlation, a fitting procedure used to compare point (grab) and depth-integrated samples where statistically significant differences exist as defined by the WSRT, indicated that point (grab) samples underestimate total phosphorus concentrations when compared to depth-integrated samples. This underestimation probably can be attributed to the reduced suspended-sediment concentrations near the surface during periods of flow as compared to those near the streambed. Predictive models were developed to estimate total nitrogen and total phosphorus loads by means of an ordinary least-squares regression technique. Instantaneous discharge was used as the independent variable, and total phosphorus load or total nitrogen load represented the dependent variable. A software program called Estimator was used to develop the regression models and to compute total nitrogen and total phosphorus loads

Estimation of nutrient discharge from the Yangtze River to the East China Sea and the identification of nutrient sources.

PubMed

Tong, Yindong; Bu, Xiaoge; Chen, Junyue; Zhou, Feng; Chen, Long; Liu, Maodian; Tan, Xin; Yu, Tao; Zhang, Wei; Mi, Zhaorong; Ma, Lekuan; Wang, Xuejun; Ni, Jing

2017-01-05

Based on a time-series dataset and the mass balance method, the contributions of various sources to the nutrient discharges from the Yangtze River to the East China Sea are identified. The results indicate that the nutrient concentrations vary considerably among different sections of the Yangtze River. Non-point sources are an important source of nutrients to the Yangtze River, contributing about 36% and 63% of the nitrogen and phosphorus discharged into the East China Sea, respectively. Nutrient inputs from non-point sources vary among the sections of the Yangtze River, and the contributions of non-point sources increase from upstream to downstream. Considering the rice growing patterns in the Yangtze River Basin, the synchrony of rice tillering and the wet seasons might be an important cause of the high nutrient discharge from the non-point sources. Based on our calculations, a reduction of 0.99Tg per year in total nitrogen discharges from the Yangtze River would be needed to limit the occurrences of harmful algal blooms in the East China Sea to 15 times per year. The extensive construction of sewage treatment plants in urban areas may have only a limited effect on reducing the occurrences of harmful algal blooms in the future. Copyright © 2016 Elsevier B.V. All rights reserved.

Pathways of nutrient loading and impacts on plant diversity in a New York peatland

USGS Publications Warehouse

Drexler, J.Z.; Bedford, B.L.

2002-01-01

Nutrient loading is a subtle, yet serious threat to the preservation of high diversity wetlands such as peatlands. Pathways of nutrient loading and impacts on plant diversity in a small peatland in New York State, USA were determined by collecting and analyzing a suite of hydrogeological, hydro-chemical, soil, and vegetation data. Piezometer clusters within an intensive network constituted hydro-chemical sampling points and focal points for randomly selected vegetation quadrats and soil-coring locations. Hydrogeological data and nutrient analyses showed that P and K loading occurred chiefly by means of overland flow from an adjacent farm field, whereas N loading occurred predominantly through ground-water flow from the farm field. Redundancy analysis and polynomial regression showed that nutrients, particularly total P in peat, total K in peat, extractable NH4-N, and NO3-N flux in ground water, were strongly negatively correlated with plant diversity measures at the site. No other environmental variables except vegetation measures associated with eutrophication demonstrated such a strong relationship with plant diversity. Nitrate loading over 4 mg m -2 day-1 was associated with low plant diversity, and Ca fluxes between 80 and 130 mg m-2 day-1 were associated with high plant diversity. Areas in the site with particularly low vascular plant and bryophyte species richness and Shannon-Wiener diversity (H') occurred adjacent to the farm field and near a hillside spring. High H' and species richness of vascular plants and bryophytes occurred in areas that were further removed from agriculture, contained no highly dominant vegetation, and were situated directly along the ground-water flow paths of springs. These areas were characterized by relatively constant water levels and consistent, yet moderate fluxes of base cations and nutrients. Overall, this study demonstrates that knowledge of site hydrogeology is crucial for determining potential pathways of nutrient loading and for developing relationships between nutrient inflows and wetland plant diversity. ?? 2002, The Society of Wetland Scientists.

Sources and transport of algae and nutrients in a Californian river in a semi-arid climate

USGS Publications Warehouse

Ohte, N.; Dahlgren, R.A.; Silva, S.R.; Kendall, C.; Kratzer, C.R.; Doctor, D.H.

2007-01-01

1. To elucidate factors contributing to dissolved oxygen (DO) depletion in the Stockton Deep Water Ship Channel in the lower San Joaquin River, spatial and temporal changes in algae and nutrient concentrations were investigated in relation to flow regime under the semiarid climate conditions. 2. Chlorophyll-a (chl-a) concentration and loads indicated that most algal biomass was generated by in-stream growth in the main stem of the river. The addition of algae from tributaries and drains was small (c.15% of total chl-a load), even though high concentrations of chl-a were measured in some source waters. 3. Nitrate and soluble-reactive phosphorus (SRP) were available in excess as a nutrient source for algae. Although nitrate and SRP from upstream tributaries contributed (16.9% of total nitrate load and 10.8% of total SRP load), nutrients derived from agriculture and other sources in the middle and lower river reaches were mostly responsible (20.2% for nitrate and 48.0% for SRP) for maintaining high nitrate and SRP concentrations in the main stem. 4. A reduction in nutrient discharge would attenuate the algal blooms that accelerate DO depletion in the Stockton Deep Water Ship Channel. The N : P ratio, in the main stem suggests that SRP reduction would be a more viable option for algae reduction than nitrogen reduction. 5. Very high algal growth rates in the main stem suggest that reducing the algal seed source in upstream areas would also be an effective strategy. ?? 2007 Blackwell Publishing Ltd.

Mapping of chlorophyll a distributions in coastal zones

NASA Technical Reports Server (NTRS)

Johnson, R. W.

1978-01-01

It is pointed out that chlorophyll a is an important environmental parameter for monitoring water quality, nutrient loads, and pollution effects in coastal zones. High chlorophyll a concentrations occur in areas which have high nutrient inflows from sources such as sewage treatment plants and industrial wastes. Low chlorophyll a concentrations may be due to the addition of toxic substances from industrial wastes or other sources. Remote sensing provides an opportunity to assess distributions of water quality parameters, such as chlorophyll a. A description is presented of the chlorophyll a analysis and a quantitative mapping of the James River, Virginia. An approach considered by Johnson (1977) was used in the analysis. An application of the multiple regression analysis technique to a data set collected over the New York Bight, an environmentally different area of the coastal zone, is also discussed.

Phosphorus Loadings Associated with a Park Tourist Attraction: Limnological Consequences of Feeding the Fish

NASA Astrophysics Data System (ADS)

Turner, Andrew M.; Ruhl, Nathan

2007-04-01

The Linesville spillway of Pymatuning State Park is one of the most visited tourist attractions in Pennsylvania, USA, averaging more than 450,000 visitors · year-1. Carp ( Cyprinus carpio Linnaeus) and waterfowl congregate at the spillway where they are fed bread and other foods by park visitors. We hypothesized that the “breadthrowers” constitute a significant nutrient vector to the upper portion of Pymatuning Reservoir. In the summer of 2002, we estimated phosphorus loadings attributable to breadthrowers, and compared these values to background loadings from Linesville Creek, a major tributary to the upper reservoir. Items fed to fish included bread, donuts, bagels, canned corn, popcorn, corn chips, hot dogs, birthday cakes, and dog food. Phosphorus loading associated with park visitors feeding fish was estimated to be 3233 g day-1, and estimated P export from the Linesville Creek watershed was 2235 g·day-1. P loading attributable to breadthrowers exceeded that of the entire Linesville Creek watershed on 33 of the 35 days of study, with only a heavy rainfall event triggering watershed exports that exceeded spillway contributions. Averaged across 5 weeks, breadthrowers contributed 1.45-fold more P to Pymatuning Reservoir than the Linesville Creek watershed. If Linesville Creek P exports are extrapolated to the entire Sanctuary Lake watershed, spillway contributions of P added 48% to the non-point source watershed P entering the lake. Park visitors feeding fish at the Linesville Spillway are a significant source of nutrients entering Sanctuary Lake.

Water-quality conditions of the lower Boise River, Ada and Canyon Counties, Idaho, May 1994 through February 1997

USGS Publications Warehouse

Mullins, William H.

1998-01-01

Agricultural land and water use, wastewater treatment facility discharges, land development, road construction, urban runoff, confined-animal feeding operations, reservoir operations, and river channelization affect the water quality and biotic integrity of the lower Boise River between Lucky Peak Dam and the river's mouth at Parma, Idaho. During May 1994 through February 1997, 4 sites on the Boise River, 12 tributary/drain sites, and 3 wastewater treatment facilities were sampled at various intervals during the irrigation (high-flow) and post-irrigation (low-flow) seasons to determine sources, concentrations, and relative loads of nutrients and suspended sediment. Discharge entering the Boise River from the 12 tributary/drain sites and 3 wastewater treatment facilities was measured to determine the nutrient loads being contributed from each source. Total nitrogen, total phosphorus, and suspended sediment concentrations and loads tended to increase in a downstream direction along the Boise River. Among the 15 sources of discharge to the Boise River, 3 southside tributary/drains and the West Boise wastewater treatment facility contributed the largest loads of total nitrogen; the median daily load was more than 2,000 pounds per day. The West Boise wastewater treatment facility contributed the largest median daily load of total phosphorus (810 pounds per day); Dixie Drain contributed the largest median daily load of suspended sediment (26.4 tons per day). Nitrogen-to-phosphorus ratios at the four Boise River sites indicated that phosphorus could be limiting algal growth at the Diversion Dam site, whereas nitrogen could be limiting algal growth at the Glenwood and Middleton sites during some parts of the year. Algal growth in the Boise River near Parma did not appear to be nutrient limited. Because of the complexity of the plumbing system in the lower Boise River (numerous diversions and inflow points), accurate comparisons between discharge and nutrient loads entering the river at measured sites during high-flow sampling periods were difficult. During low-flow sampling periods, southside tributary/drains contributed most of the discharge and total nitrogen load, and wastewater treatment facilities contributed most of the total phosphorus load to the Boise River. During the 50-day period July 18 through September 5, 1996, the Idaho State standard for maximum daily average temperature for coldwater biota was exceeded by 34 percent at Middleton, 48 percent at Caldwell, and 80 percent near Parma. Violations of State standards for primary and secondary contact recreation were observed at all tributary/ drains and in the Boise River near Parma. Median instantaneous concentrations of fecal coliform bacteria exceeded State standards for primary contact recreation at five tributary/drains and exceeded standards for secondary contact recreation at one tributary/drain (Dixie Drain).

Nutrient load estimates for Manila Bay, Philippines using population data

NASA Astrophysics Data System (ADS)

Sotto, Lara Patricia A.; Beusen, Arthur H. W.; Villanoy, Cesar L.; Bouwman, Lex F.; Jacinto, Gil S.

2015-06-01

A major source of nutrient load to periodically hypoxic Manila Bay is the urban nutrient waste water flow from humans and industries to surface water. In Manila alone, the population density is as high as 19,137 people/km2. A model based on a global point source model by Morée et al. (2013) was used to estimate the contribution of the population to nitrogen and phosphorus emissions which was then used in a water transport model to estimate the nitrogen (N) and phosphorus (P) loads to Manila Bay. Seven scenarios for 2050 were tested, with varying degrees and amounts for extent of sewage treatment, and population growth rates were also included. In scenario 1, the sewage connection and treatment remains the same as 2010; in scenario 2, sewage connection is improved but the treatment is the same; in scenario 3, the sewage connection as well as treatment is improved (70% tertiary); and in scenario 4, a more realistic situation of 70% primary treatment achieved with 100% connection to pipes is tested. Scenarios 5, 6, and 7 have the same parameters as 1, 2, and 3 respectively, but with the population growth rate per province reduced to half of what was used in 1, 2, and 3. In all scenarios, a significant increase in N and P loads was observed (varying from 27% to 469% relative to 2010 values). This was found even in scenario 3 where 70% of the waste water undergoes tertiary treatment which removes 80% N and 90% P. However, the lowest increase in N and P load into the bay was achieved in scenarios 5 to 7 where population growth rate is reduced to half of 2010 values. The results suggest that aside from improving sewage treatment, the continued increase of the human population in Manila at current growth rates will be an important determinant of N and P load into Manila Bay.

Modeling nutrient release in the Tai Lake basin of China: source identification and policy implications.

PubMed

Liu, Beibei; Liu, Heng; Zhang, Bing; Bi, Jun

2013-03-01

Because nutrient enrichment has become increasingly severe in the Tai Lake Basin of China, identifying sources and loads is crucial for watershed nutrient management. This paper develops an empirical framework to estimate nutrient release from five major sectors, which requires fewer input parameters and produces acceptable accuracy. Sectors included are industrial manufacturing, livestock breeding (industrial and family scale), crop agriculture, household consumption (urban and rural), and atmospheric deposition. Results show that in the basin (only the five sectors above), total nutrient loads of nitrogen (N) and phosphorus (P) into aquatic systems in 2008 were 33043.2 tons N a(-1) and 5254.4 tons P a(-1), and annual area-specific nutrient loads were 1.94 tons N km(-2) and 0.31 tons P km(-2). Household consumption was the major sector having the greatest impact (46 % in N load, 47 % in P load), whereas atmospheric deposition (18 %) and crop agriculture (15 %) sectors represented other significant proportions of N load. The load estimates also indicate that 32 % of total P came from the livestock breeding sector, making it the second largest phosphorus contributor. According to the nutrient pollution sectors, six best management practices are selected for cost-effectiveness analysis, and feasible options are recommended. Overall, biogas digester construction on industrial-scale farms is proven the most cost-effective, whereas the building of rural decentralized facilities is the best alternative under extreme financial constraint. However, the reduction potential, average monetary cost, and other factors such as risk tolerance of policy makers should all be considered in the actual decision-making process.

Distribution of green algal mats throughout shallow soft bottoms of the Swedish Skagerrak archipelago in relation to nutrient sources and wave exposure

NASA Astrophysics Data System (ADS)

Pihl, Leif; Svenson, Anders; Moksnes, Per-Olav; Wennhage, Håkan

1999-06-01

Distribution and biomass of green algal mats were studied in marine shallow (0-1 m) soft-bottom areas on the Swedish west coast from 1994 to 1996, by combining aerial photography surveys with ground truth sampling. Filamentous green algae, dominated by species of the genera Cladophora and Enteromorpha, were generally present throughout the study area during July and August, and largely absent in late April and early May. These algae occurred at 60 to 90% of the locations investigated during the summer, and were estimated to cover between 30 and 50% of the total area of shallow soft bottoms of the Swedish Skagerrak archipelago. The distributional patterns were similar during the three years of the investigation and appeared unrelated to annual local nutrient inputs from point sources and river discharge. We postulate that the apparent lack of such a relationship is due to an altered state of nutrient dynamics throughout the archipelago. Mechanisms are likely to involve long-term, diffuse elevations in nutrient levels in coastal waters of the Skagerrak and the Kattegat over several decades leading to current eutrophic conditions, exceeding nutrient requirements for abundant filamentous algal growth. Patterns of algal abundance in our study were largely related to physical factors such as exposure to wind, waves and water exchange under conditions where nutrient loads among embayments seemed to be unlimited. Further, our results show that sediments covered by algal mats had higher carbon and nitrogen contents than unvegetated sediments. We hypothesise that sustained high nutrient loads, manifested in extensive biomass of filamentous algae during summer months, are re-mineralised via decay and sedimentation in the benthic realm. Hence, accumulated carbon and nutrients in the sediment could, in turn, constitute the basic pool for future algal mat production overlying soft bottoms in areas where tidal exchange is limited.

Trends In Nutrient and Sediment Concentrations and Loads In Major River Basins of the South-Central United States, 1993-2004

USGS Publications Warehouse

Rebich, Richard A.; Demcheck, Dennis K.

2008-01-01

Nutrient and sediment data collected at 115 sites by Federal and State agencies from 1993 to 2004 were analyzed by the U.S. Geological Survey to determine trends in concentrations and loads for selected rivers and streams that drain into the northwestern Gulf of Mexico from the south-central United States, specifically from the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf Basins. Trends observed in the study area were compared to determine potential regional patterns and to determine cause-effect relations with trends in hydrologic and human-induced factors such as nutrient sources, streamflow, and implementation of best management practices. Secondary objectives included calculation of loads and yields for the study period as a basis for comparing the delivery of nutrients and sediment to the northwestern Gulf of Mexico from the various rivers within the study area. In addition, loads were assessed at seven selected sites for the period 1980-2004 to give hydrologic perspective to trends in loads observed during 1993-2004. Most study sites (about 64 percent) either had no trends or decreasing trends in streamflow during the study period. The regional pattern of decreasing trends in streamflow during the study period appeared to correspond to moist conditions at the beginning of the study period and the influence of three drought periods during the study period, of which the most extreme was in 2000. Trend tests were completed for ammonia at 49 sites, for nitrite plus nitrate at 69 sites, and for total nitrogen at 41 sites. For all nitrogen constituents analyzed, no trends were observed at half or more of the sites. No regional trend patterns could be confirmed because there was poor spatial representation of the trend sites. Decreasing trends in flow-adjusted concentrations of ammonia were observed at 25 sites. No increasing trends in concentrations of ammonia were noted at any sites. Flow-adjusted concentrations of nitrite plus nitrate decreased at 7 sites and increased at14 sites. Flow-adjusted concentrations of total nitrogen decreased at 2 sites and increased at 12 sites. Improvements to municipal wastewater treatment facilities contributed to the decline of ammonia concentrations at selected sites. Notable increasing trends in nitrite plus nitrate and total nitrogen at selected study sites were attributed to both point and nonpointsources. Trend patterns in total nitrogen generally followed trend patterns in nitrite plus nitrate, which was understandable given that nitrite plus nitrate loads generally were 70-90 percent of the total nitrogen loads at most sites. Population data were used as a surrogate to understand the relation between changes in point sources and nutrient trends because data from wastewater treatment plants were inconsistent for this study area. Although population increased throughout the study area during the study period, there was no observed relation between increasing trends in nitrogen in study area streams and increasing trends in population. With respect to other nitrogen sources, statistical results did suggest that increasing trends in nitrogen could be related to increasing trends in nitrogen from either commercial fertilizer use and/or land application of manure. Loads of ammonia, nitrite plus nitrate, and total nitrogen decreased during the study period, but some trends in nitrogen loads were part of long-term decreases since 1980. For example, ammonia loads were shown to decrease at nearly all sites over the past decade, but at selected sites, these decreasing trends were part of much longer trends since 1980. The Mississippi and Atchafalaya Rivers contributed the highest nitrogen loads to the northwestern Gulf of Mexico as expected; however, nitrogen yields from smaller rivers had similar or higher yields than yields from the Mississippi River. Trend tests were completed for orthophosphorus at 34 sites and for total phosphorus at 52 sites. No trends were observed in abo

Constituent concentrations, loads, and yields to Beaver Lake, Arkansas, water years 1999-2008

USGS Publications Warehouse

Bolyard, Susan E.; De Lanois, Jeanne L.; Green, W. Reed

2010-01-01

Beaver Lake is a large, deep-storage reservoir used as a drinking-water supply and considered a primary watershed of concern in the State of Arkansas. As such, information is needed to assess water quality, especially nutrient enrichment, nutrient-algal relations, turbidity, and sediment issues within the reservoir system. Water-quality samples were collected at three main inflows to Beaver Lake: the White River near Fayetteville, Richland Creek at Goshen, and War Eagle Creek near Hindsville. Water-quality samples collected over the period represented different flow conditions (from low to high). Constituent concentrations, flow-weighted concentrations, loads, and yields from White River, Richland Creek, and War Eagle Creek to Beaver Lake for water years 1999-2008 were documented for this report. Constituents include total ammonia plus organic nitrogen, dissolved nitrite plus nitrate nitrogen, dissolved orthophosphorus (soluble reactive phosphorus), total phosphorus, total nitrogen, dissolved organic carbon, total organic carbon, and suspended sediment. Linear regression models developed by computer program S-LOADEST were used to estimate loads for each constituent for the 10-year period at each station. Constituent yields and flow-weighted concentrations for each of the three stations were calculated for the study. Constituent concentrations and loads and yields varied with time and varied among the three tributaries contributing to Beaver Lake. These differences can result from differences in precipitation, land use, contributions of nutrients from point sources, and variations in basin size. Load and yield estimates varied yearly during the study period, water years 1999-2008, with the least nutrient and sediment load and yields generally occurring in water year 2006, and the greatest occurring in water year 2008, during a year with record amounts of precipitation. Flow-weighted concentrations of most constituents were greatest at War Eagle Creek near Hindsville than White River near Fayetteville and Richland Creek at Goshen. Loads and yields of most constituents were greater at the War Eagle Creek and White River stations than at the Richland Creek Station.

Lake Nutrient Responses to Integrated Conservation Practices in an Agricultural Watershed.

PubMed

Lizotte, Richard E; Yasarer, Lindsey M W; Locke, Martin A; Bingner, Ronald L; Knight, Scott S

2017-03-01

Watershed-scale management efforts to reduce nutrient loads and improve the conservation of lakes in agricultural watersheds require effective integration of a variety of agricultural conservation best management practices (BMPs). This paper documents watershed-scale assessments of the influence of multiple integrated BMPs on oxbow lake nutrient concentrations in a 625-ha watershed of intensive row-crop agricultural activity during a 14-yr monitoring period (1996-2009). A suite of BMPs within fields and at field edges throughout the watershed and enrollment of 87 ha into the Conservation Reserve Program (CRP) were implemented from 1995 to 2006. Total phosphorus (TP), soluble reactive phosphorus (SRP), ammonium, and nitrate were measured approximately biweekly from 1996 to 2009, and total nitrogen (TN) was measured from 2001 to 2009. Decreases in several lake nutrient concentrations occurred after BMP implementation. Reductions in TP lake concentrations were associated with vegetative buffers and rainfall. No consistent patterns of changes in TN or SRP lake concentrations were observed. Reductions in ammonium lake concentrations were associated with conservation tillage and CRP. Reductions in nitrate lake concentrations were associated with vegetative buffers. Watershed simulations conducted with the AnnAGNPS (Annualized Agricultural Non-Point Source) model with and without BMPs also show a clear reduction in TN and TP loads to the lake after the implementation of BMPs. These results provide direct evidence of how watershed-wide BMPs assist in reducing nutrient loading in aquatic ecosystems and promote a more viable and sustainable lake ecosystem. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Performance of five plant species in removal of nitrogen and phosphorus from an experimental phytoremediation system in the Ningxia irrigation area.

PubMed

Chen, Chongjuan; Zhao, Tiancheng; Liu, Ruliang; Luo, Liangguo

2017-09-10

Agricultural non-point source (ANPS) pollution is an important contributor to elevated nitrogen (N) and phosphorus (P) in surface waters, which can cause serious environmental problems. Considerable effort has therefore gone into the development of methods that control the ANPS input of N and P to surface waters. Phytoremediation has been extensively used because it is cost-effective, environmentally friendly, and efficient. The N and P loads from agricultural drainage are a potential threat to the water quality of the Yellow River in Ningxia, China. Yet, phytoremediation has only rarely been applied within the Ningxia irrigation area. In an experimental set-up, five species (Ipomoea aquatica, IA; Lactuca sativa, LS; Oryza sativa, OS; Typha latifolia, TL; Zizania latifolia, ZL) were evaluated for their ability to reduce N and P loads over 62 days and five observation periods. Total N and P concentrations, plant biomass, and nutrient content were measured. The results showed that OS, LS, and IA performed better than ZL and TL in terms of nutrients removal, biomass accumulation, and nutrients storage. The highest overall removal rates of N and P (57.7 and 57.3%, respectively) were achieved by LS treatment. In addition, plant uptake contributed significantly to nutrient removal, causing a 25.9-72.0% reduction in N removal and a 54.3-86.5% reduction in P removal. Thus, this study suggests that OS, LS, and IA would be more suitable than ZL and TL for controlling nutrient loads in the Ningxia irrigation area using phytoremediation.

Scenario analysis of the impacts of socioeconomic development on phosphorous export and loading from the Dongting Lake watershed, China.

PubMed

Hou, Ying; Chen, Weiping; Liao, Yuehua; Luo, Yueping

2017-12-01

Socioeconomic development in lake watersheds is closely related with lake nutrient pollution. As the second largest freshwater lake in China, the Dongting Lake has been experiencing an increase in nutrient loading and a growing risk of eutrophication. This study aimed to reveal the likely impacts of the socioeconomic development of the Dongting Lake watershed on the phosphorous pollution in the lake. We estimated the contributions from different sources and sub-watersheds to the total phosphorous (TP) export and loading from the Dongting Lake watershed under two most likely socioeconomic development scenarios. Moreover, we predicted the likely permissible and actual TP loadings to the Dongting Lake. Under both two scenarios, three secondary sub-watersheds-the upper and lower reaches of the Xiang River watershed and the Dongting Lake Area-are expected to dominate the contribution to the TP export from the Dongting Lake watershed in 2020. Three primary sub-watersheds-the Dongting Lake Area, the Xiang River, and the Yuan River watersheds-are predicted to be the major contributors to the TP loading from the entire watershed. The two scenarios are expected to have a slight difference in TP export and lake TP loading. Livestock husbandry is expected to be the predominant anthropogenic TP source in each of the sub-watersheds under both scenarios. Compared to 2010, permissible TP loading is not expected to increase but actual TP loading is predicted to grow significantly in 2020. Our study provides methodologies to identify the key sources and regions of lake nutrient loading from watersheds with complex socioeconomic context, and to reveal the potential influences of socioeconomic development on nutrient pollution in lake watersheds.

Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate Scale Water Quality Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khangaonkar, Tarang; Sackmann, Brandon S.; Long, Wen

2012-10-01

The Salish Sea, including Puget Sound, is a large estuarine system bounded by over seven thousand miles of complex shorelines, consists of several subbasins and many large inlets with distinct properties of their own. Pacific Ocean water enters Puget Sound through the Strait of Juan de Fuca at depth over the Admiralty Inlet sill. Ocean water mixed with freshwater discharges from runoff, rivers, and wastewater outfalls exits Puget Sound through the brackish surface outflow layer. Nutrient pollution is considered one of the largest threats to Puget Sound. There is considerable interest in understanding the effect of nutrient loads on themore » water quality and ecological health of Puget Sound in particular and the Salish Sea as a whole. The Washington State Department of Ecology (Ecology) contracted with Pacific Northwest National Laboratory (PNNL) to develop a coupled hydrodynamic and water quality model. The water quality model simulates algae growth, dissolved oxygen, (DO) and nutrient dynamics in Puget Sound to inform potential Puget Sound-wide nutrient management strategies. Specifically, the project is expected to help determine 1) if current and potential future nitrogen loadings from point and non-point sources are significantly impairing water quality at a large scale and 2) what level of nutrient reductions are necessary to reduce or control human impacts to DO levels in the sensitive areas. The project did not include any additional data collection but instead relied on currently available information. This report describes model development effort conducted during the period 2009 to 2012 under a U.S. Environmental Protection Agency (EPA) cooperative agreement with PNNL, Ecology, and the University of Washington awarded under the National Estuary Program« less

Intertidal and submarine groundwater discharge on the west coast of Ireland

NASA Astrophysics Data System (ADS)

R., R.; | T., Cave; Henry

2011-05-01

Submarine Groundwater Discharge is now a phenomenon of global interest, as studies show that it represents both a significant proportion of the fresh water input to the ocean, and a significant contribution to the loads of many substances. At present, little monitoring of groundwater in Ireland is carried out at its point of entry to seawater, and consequently the volumes of fresh water, and the loads of nutrients and contaminants being carried into Irish coastal waters by submarine and intertidal groundwater discharge (SiGD), are unknown. SiGD is the principal source of fresh water entering Irish coastal waters between the major west coast estuaries of the Corrib and the Shannon. Calculations of the volume of submarine SiGD delivered to southern Galway bay in winter indicate it equals 10-25% of the discharge of the R. Corrib, and that its nutrient load may be of the same order of magnitude as that from the R. Corrib. This coastal karst area includes important commercial shellfish waters, which may be strongly impacted by SiGD.

Seasonal variations of nitrogen and phosphorus retention in an agricultural drainage river in East China.

PubMed

Chen, Dingjiang; Lu, Jun; Wang, Hailong; Shen, Yena; Kimberley, Mark O

2010-02-01

Riverine retention decreases loads of nitrogen (N) and phosphorus (P) in running water. It is an important process in nutrient cycling in watersheds. However, temporal riverine nutrient retention capacity varies due to changes in hydrological, ecological, and nutrient inputs into the watershed. Quantitative information of seasonal riverine N and P retention is critical for developing strategies to combat diffuse source pollution and eutrophication in riverine and coastal systems. This study examined seasonal variation of riverine total N (TN) and total P (TP) retention in the ChangLe River, an agricultural drainage river in east China. Water quality, hydrological parameters, and hydrophyte coverage were monitored along the ChangLe River monthly during 2004-2006. Nutrient export loads (including chemical fertilizer, livestock, and domestic sources) entering the river from the catchment area were computed using an export coefficient model based on estimated nutrient sources. Riverine TN and TP retention loads (RNRL and RPRL) were estimated using mass balance calculations. Temporal variations in riverine nutrient retention were analyzed statistically. Estimated annual riverine retention loads ranged from 1,538 to 2,127 t year(-1) for RNRL and from 79.4 to 90.4 t year(-1) for RPRL. Monthly retention loads varied from 6.4 to 300.8 t month(-1) for RNRL and from 1.4 to 15.3 t month(-1) for RPRL. Both RNRL and RPRL increased with river flow, water temperature, hydrophyte coverage, monthly sunshine hours, and total TN and TP inputs. Dissolved oxygen concentration and the pH level of the river water decreased with RNRL and RPRL. Riverine nutrient retention ratios (retention as a percentage of total input) were only related to hydrophyte coverage and monthly sunshine hours. Monthly variations in RNRL and RPRL were functions of TN and TP loads. Riverine nutrient retention capacity varied with environmental conditions. Annual RNRL and RPRL accounted for 30.3-48.3% and 52.5-71.2%, respectively, of total input TN and TP loads in the ChangLe River. Monthly riverine retention ratios were 3.5-88.7% for TN and 20.5-92.6% for TP. Hydrophyte growth and coverage on the river bed is the main cause for seasonal variation in riverine nutrient retention capacity. The total input TN and TP loads were the best indicators of RNRL and RPRL, respectively. High riverine nutrient retention capacity during summer due to hydrophytic growth is favorable to the avoidance of algal bloom in both river systems and coastal water in southeast China. Policies should be developed to strictly control nutrient applications on agricultural lands. Strategies for promoting hydrophyte growth in rivers are desirable for water quality management.

Using high-frequency sensors to identify hydroclimatological controls on storm-event variability in catchment nutrient fluxes and source zone activation

NASA Astrophysics Data System (ADS)

Blaen, Phillip; Khamis, Kieran; Lloyd, Charlotte; Krause, Stefan

2017-04-01

At the river catchment scale, storm events can drive highly variable behaviour in nutrient and water fluxes, yet short-term dynamics are frequently missed by low resolution sampling regimes. In addition, nutrient source contributions can vary significantly within and between storm events. Our inability to identify and characterise time dynamic source zone contributions severely hampers the adequate design of land use management practices in order to control nutrient exports from agricultural landscapes. Here, we utilise an 8-month high-frequency (hourly) time series of streamflow, nitrate concentration (NO3) and fluorescent dissolved organic matter concentration (FDOM) derived from optical in-situ sensors located in a headwater agricultural catchment. We characterised variability in flow and nutrient dynamics across 29 storm events. Storm events represented 31% of the time series and contributed disproportionately to nutrient loads (43% of NO3 and 36% of CDOM) relative to their duration. Principal components analysis of potential hydroclimatological controls on nutrient fluxes demonstrated that a small number of components, representing >90% of variance in the dataset, were highly significant model predictors of inter-event variability in catchment nutrient export. Hysteresis analysis of nutrient concentration-discharge relationships suggested spatially discrete source zones existed for NO3 and FDOM, and that activation of these zones varied on an event-specific basis. Our results highlight the benefits of high-frequency in-situ monitoring for characterising complex short-term nutrient dynamics and unravelling connections between hydroclimatological variability and river nutrient export and source zone activation under extreme flow conditions. These new process-based insights are fundamental to underpinning the development of targeted management measures to reduce nutrient loading of surface waters.

Modeling Nitrogen Processing in Northeast US River Networks

NASA Astrophysics Data System (ADS)

Whittinghill, K. A.; Stewart, R.; Mineau, M.; Wollheim, W. M.; Lammers, R. B.

2013-12-01

Due to increased nitrogen (N) pollution from anthropogenic sources, the need for aquatic ecosystem services such as N removal has also increased. River networks provide a buffering mechanism that retains or removes anthropogenic N inputs. However, the effectiveness of N removal in rivers may decline with increased loading and, consequently, excess N is eventually delivered to estuaries. We used a spatially distributed river network N removal model developed within the Framework for Aquatic Modeling in the Earth System (FrAMES) to examine the geography of N removal capacity of Northeast river systems under various land use and climate conditions. FrAMES accounts for accumulation and routing of runoff, water temperatures, and serial biogeochemical processing using reactivity derived from the Lotic Intersite Nitrogen Experiment (LINX2). Nonpoint N loading is driven by empirical relationships with land cover developed from previous research in Northeast watersheds. Point source N loading from wastewater treatment plants is estimated as a function of the population served and the volume of water discharged. We tested model results using historical USGS discharge data and N data from historical grab samples and recently initiated continuous measurements from in-situ aquatic sensors. Model results for major Northeast watersheds illustrate hot spots of ecosystem service activity (i.e. N removal) using high-resolution maps and basin profiles. As expected, N loading increases with increasing suburban or agricultural land use area. Network scale N removal is highest during summer and autumn when discharge is low and river temperatures are high. N removal as the % of N loading increases with catchment size and decreases with increasing N loading, suburban land use, or agricultural land use. Catchments experiencing the highest network scale N removal generally have N inputs (both point and non-point sources) located in lower order streams. Model results can be used to better predict nutrient loading to the coastal ocean across a broad range of current and future climate variability.

Combining Natural Attenuation Capacity and use of Targeted Technological Mitigation Measures for Reducing Diffuse Nutrient Emissions to Surface Waters: The Danish Way

NASA Astrophysics Data System (ADS)

Kronvang, B.; Højberg, A. L.; Hoffmann, C. C.; Windolf, J.; Blicher-Mathiesen, G.

2015-12-01

Excess nitrogen (N) and phosphorus (P) emissions to surface waters are a high priority environmental problem worldwide for protection of water resources in times of population growth and climate change. As clean water is a scarce resource the struggle for reducing nutrient emissions are an ongoing issue for many countries and regions. Since the mid1980s a wide range of national regulatory general measures have been implemented to reduce land based nitrogen (N) and phosphorus (P) loadings of the Danish aquatic environment. These measures have addressed both point source emissions and emissions from diffuse sources especially from agricultural production. Following nearly 4 decades of combating nutrient pollution our surface waters such as lakes and estuaries are only slowly responding on the 50% reduction in N and 56% reduction in P. Therefore, the implementation of the EU Water Framework Directive in Danish surface waters still call for further reductions of N and P loadings. Therefore, a new era of targeted implemented measures was the outcome of a Commission on Nature and Agriculture established by the Danish Government in 2013. Their White Book points to the need of increased growth and better environment through more targeted and efficient regulation using advanced technological mitigation methods that are implemented intelligently according to the local natural attenuation capacity for nutrients in the landscape. As a follow up a national consensus model for N was established chaining existing leaching, 3D groundwater and surface water models that enable a calculation of the N dynamics and attenuation capacity within a scale of 15 km2. Moreover, several research projects have been conducted to investigate the effect of a suite of targeted mitigation measures such as restored natural wetlands, constructed wetlands, controlled drainage, buffer strips and constructed buffer strips. The results of these studies will be shared in this presentation.

Estimation of Total Nitrogen and Phosphorus in New England Streams Using Spatially Referenced Regression Models

USGS Publications Warehouse

Moore, Richard Bridge; Johnston, Craig M.; Robinson, Keith W.; Deacon, Jeffrey R.

2004-01-01

The U.S. Geological Survey (USGS), in cooperation with the U.S. Environmental Protection Agency (USEPA) and the New England Interstate Water Pollution Control Commission (NEIWPCC), has developed a water-quality model, called SPARROW (Spatially Referenced Regressions on Watershed Attributes), to assist in regional total maximum daily load (TMDL) and nutrient-criteria activities in New England. SPARROW is a spatially detailed, statistical model that uses regression equations to relate total nitrogen and phosphorus (nutrient) stream loads to nutrient sources and watershed characteristics. The statistical relations in these equations are then used to predict nutrient loads in unmonitored streams. The New England SPARROW models are built using a hydrologic network of 42,000 stream reaches and associated watersheds. Watershed boundaries are defined for each stream reach in the network through the use of a digital elevation model and existing digitized watershed divides. Nutrient source data is from permitted wastewater discharge data from USEPA's Permit Compliance System (PCS), various land-use sources, and atmospheric deposition. Physical watershed characteristics include drainage area, land use, streamflow, time-of-travel, stream density, percent wetlands, slope of the land surface, and soil permeability. The New England SPARROW models for total nitrogen and total phosphorus have R-squared values of 0.95 and 0.94, with mean square errors of 0.16 and 0.23, respectively. Variables that were statistically significant in the total nitrogen model include permitted municipal-wastewater discharges, atmospheric deposition, agricultural area, and developed land area. Total nitrogen stream-loss rates were significant only in streams with average annual flows less than or equal to 2.83 cubic meters per second. In streams larger than this, there is nondetectable in-stream loss of annual total nitrogen in New England. Variables that were statistically significant in the total phosphorus model include discharges for municipal wastewater-treatment facilities and pulp and paper facilities, developed land area, agricultural area, and forested area. For total phosphorus, loss rates were significant for reservoirs with surface areas of 10 square kilometers or less, and in streams with flows less than or equal to 2.83 cubic meters per second. Applications of SPARROW for evaluating nutrient loading in New England waters include estimates of the spatial distributions of total nitrogen and phosphorus yields, sources of the nutrients, and the potential for delivery of those yields to receiving waters. This information can be used to (1) predict ranges in nutrient levels in surface waters, (2) identify the environmental variables that are statistically significant predictors of nutrient levels in streams, (3) evaluate monitoring efforts for better determination of nutrient loads, and (4) evaluate management options for reducing nutrient loads to achieve water-quality goals.

Woodchip bioreactors effectively treat aquaculture effluent

USDA-ARS?s Scientific Manuscript database

Nutrients, in particular nitrogen and phosphorus, can create eutrophication problems in any watershed. Preventing water quality impairment requires controlling nutrients from both point-source and non-point source discharges. Woodchip bioreactors are one relatively new approach that can be utilized ...

Development of an epiphyte indicator of nutrient enrichment ...

EPA Pesticide Factsheets

Metrics of epiphyte load on macrophytes were evaluated for use as quantitative biological indicators for nutrient impacts in estuarine waters, based on review and analysis of the literature on epiphytes and macrophytes, primarily seagrasses, but including some brackish and freshwater rooted macrophyte species. An approach is presented that empirically derives threshold epiphyte loads which are likely to cause specified levels of decrease in macrophyte response metrics such as biomass, shoot density, percent cover, production and growth. Data from 36 studies of 10 macrophyte species were pooled to derive relationships between epiphyte load and -25 and -50% seagrass response levels, which are proposed as the primary basis for establishment of critical threshold values. Given multiple sources of variability in the response data, threshold ranges based on the range of values falling between the median and the 75th quantiles of observations at a given seagrass response level are proposed rather than single, critical point values. Four epiphyte load threshold categories - low, moderate, high, very high, are proposed. Comparison of values of epiphyte loads associated with 25 and 50% reductions in light to macrophytes suggest that the threshold ranges are realistic both in terms of the principle mechanism of impact to macrophytes and in terms of the magnitude of resultant impacts expressed by the macrophytes. Some variability in response levels was observed among

Water and nutrient budgets for Vancouver Lake, Vancouver, Washington, October 2010-October 2012

USGS Publications Warehouse

Sheibley, Rich W.; Foreman, James R.; Marshall, Cameron A.; Welch, Wendy B.

2014-01-01

Vancouver Lake, a large shallow lake in Clark County, near Vancouver, Washington, has been undergoing water-quality problems for decades. Recently, the biggest concern for the lake are the almost annual harmful cyanobacteria blooms that cause the lake to close for recreation for several weeks each summer. Despite decades of interest in improving the water quality of the lake, fundamental information on the timing and amount of water and nutrients entering and exiting the lake is lacking. In 2010, the U.S. Geological Survey conducted a 2-year field study to quantify water flows and nutrient loads in order to develop water and nutrient budgets for the lake. This report presents monthly and annual water and nutrient budgets from October 2010–October 2012 to identify major sources and sinks of nutrients. Lake River, a tidally influenced tributary to the lake, flows into and out of the lake almost daily and composed the greatest proportion of both the water and nutrient budgets for the lake, often at orders of magnitude greater than any other source. From the water budget, we identified precipitation, evaporation and groundwater inflow as minor components of the lake hydrologic cycle, each contributing 1 percent or less to the total water budget. Nutrient budgets were compiled monthly and annually for total nitrogen, total phosphorus, and orthophosphate; and, nitrogen loads were generally an order of magnitude greater than phosphorus loads across all sources. For total nitrogen, flow from Lake River at Felida, Washington, made up 88 percent of all inputs into the lake. For total phosphorus and orthophosphate, Lake River at Felida flowing into the lake was 91 and 76 percent of total inputs, respectively. Nutrient loads from precipitation and groundwater inflow were 1 percent or less of the total budgets. Nutrient inputs from Burnt Bridge Creek and Flushing Channel composed 12 percent of the total nitrogen budget, 8 percent of the total phosphorus budget, and 21 percent of the orthophosphate budget. We identified several data gaps and areas for future research, which include the need for better understanding nutrient inputs to the lake from sediment resuspension and better quantification of indirect nutrient inputs to the lake from Salmon Creek.

Quality of water and bottom sediments, and nutrient and dissolved-solids loads in the Apopka-Beauclair Canal, Lake County, Florida, 1986-90

USGS Publications Warehouse

Schiffer, D.M.

1994-01-01

Nutrient-rich water enters Lake Beauclair and other lakes downstream from Lake Apopka in the Ocklawaha River chain of lakes in central Florida. Two sources of the nutrient-rich water are Lake Apopka outflow and drainage from farming operations adjacent to the Apopka-Beauclair Canal. Two flow and water- quality monitoring sites were established to measure nutrient and dissolved-solids loads at the outflow from lake Apopka and at a control structure on the Apopka-Beauclair Canal downstream from farming activities. Samples were collected biweekly for analysis of nutrients and monthly for analysis of major ions for 4 years. Most of the nutrient load transported through the lock and dam on the Apopka-Beauclair Canal was transported during periods of high discharge. In April 1987, when discharges were as high as 589 cubic feet per second, loads transported through the lock and dam accounted for 59 percent of the ammonia-plus- organic nitrogen load, 61 percent of the total nitrogen load, and 59 percent of the phosphorus load transported during the 1987 water year. Constituent concentrations in annual bottom sediment samples from the canal indicated that most of the constituent load is not being transported down- stream. An alternative approach was derived for determining the relative constituent load from farm input along the canal: Load computations using this approach indicated that, with the exception of phosphorus, nutrient and dissolved-solids loads due to farm activity along the canal account for 10 percent or less of the total load at the Apopka-Beauclair canal lock and dam. (USGS)

Sources and Transport of Nutrients, Organic Carbon, and Chlorophyll-a in the San Joaquin River Upstream of Vernalis, California, during Summer and Fall, 2000 and 2001

USGS Publications Warehouse

Kratzer, Charles R.; Dileanis, Peter D.; Zamora, Celia; Silva, Steven R.; Kendall, Carol; Bergamaschi, Brian A.; Dahlgren, Randy A.

2004-01-01

Oxidizable materials from the San Joaquin River upstream of Vernalis can contribute to low dissolved oxygen episodes in the Stockton Deep Water Ship Channel that can inhibit salmon migration in the fall. The U.S. Geological Survey collected and analyzed samples at four San Joaquin River sites in July through October 2000 and June through November 2001, and at eight tributary sites in 2001. The data from these sites were supplemented with data from samples collected and analyzed by the University of California at Davis at three San Joaquin River sites and eight tributary sites as part of a separate study. Streamflows in the San Joaquin River were slightly above the long-term average in 2000 and slightly below average in 2001. Nitrate loads at Vernalis in 2000 were above the long-term average, whereas loads in 2001 were close to average. Total nitrogen loads in 2000 were slightly above average, whereas loads in 2001 were slightly below average. Total phosphorus loads in 2000 and 2001 were well below average. These nutrient loads correspond with the flow-adjusted concentration trends--nitrate concentrations significantly increased since 1972 (p 0.05). Loading rates of nutrients and dissolved organic carbon increased in the San Joaquin River in the fall with the release of wetland drainage into Mud Slough and with increased reservoir releases on the Merced River. During August 2000 and September 2001, the chlorophyll-a loading rates and concentrations in the San Joaquin River declined and remained low during the rest of the sampling period. The most significant tributary sources of nutrients were the Tuolumne River, Harding Drain, and Mud Slough. The most significant tributary sources of dissolved organic carbon were Salt Slough, Mud Slough, and the Tuolumne and Stanislaus Rivers. Compared with nutrients and dissolved organic carbon, the tributaries were minor sources of chlorophyll-a, suggesting that most of the chlorophyll-a was produced in the San Joaquin River rather than its tributaries. On the basis of the carbon-to-nitrogen ratios and the d13C of particulate organic matter in the San Joaquin River and tributaries, the particulate organic matter in the river was mostly phytoplankton. On the basis of the d15N values of the particulate organic matter, and of total dissolved nitrogen and nitrate, the nitrate in the San Joaquin River probably was a significant nutrient source for the phytoplankton. The range of d15N and d18O values of nitrate in the San Joaquin River and tributaries suggest that animal waste or sewage was a significant source of nitrate in the river at the time the samples were collected.

Modeling Mitigation Activities in North Carolina Watersheds

NASA Astrophysics Data System (ADS)

Garcia, A. M.

2017-12-01

Nutrient enrichment and excessive sediment loadings have contributed to the degradation of rivers, lakes and estuaries in North Carolina. The North Carolina Department of Environmental Quality (NCDEQ) has implemented several basin-wide nutrient and sediment management strategies, yet gaps remain in understanding the impact of these strategies given the complexities in quantifying the processes that govern the transport of nutrient and sediment. In particular, improved assessment of the status of nutrient and sediment loadings to lakes and estuaries throughout the state is needed, including characterizing their sources and describing the relative contributions of different areas. The NCDEQ Division of Mitigation Services (DMS) uses watershed planning to identify and prioritize the best locations to implement stream, wetland, and riparian-buffer restoration to improve water quality. To support better decision-making for watershed restoration activities we are developing a SPARROW (SPAtially Referenced Regressions On Watershed attributes) model framework specifically for North Carolina. The SPARROW analysis (developed by the U.S. Geological Survey) relates water-quality monitoring data to better understand the effects of human activities and natural processes on surface-water quality. The core of the model consists of using a nonlinear-regression equation to describe the non-conservative transport of contaminants from point and nonpoint sources on land to rivers, lakes and estuaries through the stream and river network. In this presentation, preliminary total Nitrogen, total Phosphorus, and Total Suspended Solids (TSS) NC-SPARROW models are described that illustrate the SPARROW modeling framework incorporating specific restoration datasets and activity metrics, such as extent of riparian buffer and easements.

Cultural eutrophication control through water reuse.

PubMed

Sala, L; Mujeriego, R

2001-01-01

The increasing use of mineral fertilisers over the last decades has contributed to the appearance of numerous cases of water eutrophication, a new form of water pollution. The starting point of eutrophication is the increase of nutrient concentration (nitrogen and phosphorus) in a water mass, which is subsequently followed by an uncontrolled growth of primary producers and episodes of oxygen depletion due to microbial decomposition of algal organic matter. The excess nutrient loads reaching surface waters are usually associated to discharges from anthropogenic activities, which normally involve direct water usage instead of reuse of reclaimed effluents. Agriculture activities and livestock breeding are two of the main nutrient sources responsible for water eutrophication, as well as human--urban and industrial--wastewater discharges. Wastewater reclamation and reuse can be a suitable strategy for preserving the quality of natural waters, by suppressing effluent discharges and the associated nutrient contributions to receiving waters. Reuse of reclaimed water for agricultural and landscape irrigation as well as for environmental enhancement offers an adequate strategy for preserving natural water systems from eutrophication.

Nutrient load summaries for major lakes and estuaries of the Eastern United States, 2002

USGS Publications Warehouse

Moorman, Michelle C.; Hoos, Anne B.; Bricker, Suzanne B.; Moore, Richard B.; García, Ana María; Ator, Scott W.

2014-01-01

Nutrient enrichment of lakes and estuaries across the Nation is widespread. Nutrient enrichment can stimulate excessive plant and algal growth and cause a number of undesirable effects that impair aquatic life and recreational activities and can also result in economic effects. Understanding the amount of nutrients entering lakes and estuaries, the physical characteristics affecting the nutrient processing within these receiving waterbodies, and the natural and manmade sources of nutrients is fundamental to the development of effective nutrient reduction strategies. To improve this understanding, sources and stream transport of nutrients to 255 major lakes and 64 estuaries in the Eastern United States were estimated using Spatially Referenced Regression on Watershed attributes (SPARROW) nutrient models.

Variability in climate change simulations affects needed long-term riverine nutrient reductions for the Baltic Sea.

PubMed

Bring, Arvid; Rogberg, Peter; Destouni, Georgia

2015-06-01

Changes to runoff due to climate change may influence management of nutrient loading to the sea. Assuming unchanged river nutrient concentrations, we evaluate the effects of changing runoff on commitments to nutrient reductions under the Baltic Sea Action Plan. For several countries, climate projections point to large variability in load changes in relation to reduction targets. These changes either increase loads, making the target more difficult to reach, or decrease them, leading instead to a full achievement of the target. The impact of variability in climate projections varies with the size of the reduction target and is larger for countries with more limited commitments. In the end, a number of focused actions are needed to manage the effects of climate change on nutrient loads: reducing uncertainty in climate projections, deciding on frameworks to identify best performing models with respect to land surface hydrology, and increasing efforts at sustained monitoring of water flow changes.

Variability in climate change simulations affects needed long-term riverine nutrient reductions for the Baltic Sea

DOE PAGES

Bring, Arvid; Rogberg, Peter; Destouni, Georgia

2015-05-28

Changes to runoff due to climate change may influence management of nutrient loading to the sea. Assuming unchanged river nutrient concentrations, we evaluate the effects of changing runoff on commitments to nutrient reductions under the Baltic Sea Action Plan. For several countries, climate projections point to large variability in load changes in relation to reduction targets. These changes either increase loads, making the target more difficult to reach, or decrease them, leading instead to a full achievement of the target. The impact of variability in climate projections varies with the size of the reduction target and is larger for countriesmore » with more limited commitments. Finally, in the end, a number of focused actions are needed to manage the effects of climate change on nutrient loads: reducing uncertainty in climate projections, deciding on frameworks to identify best performing models with respect to land surface hydrology, and increasing efforts at sustained monitoring of water flow changes.« less

Variability in climate change simulations affects needed long-term riverine nutrient reductions for the Baltic Sea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bring, Arvid; Rogberg, Peter; Destouni, Georgia

Changes to runoff due to climate change may influence management of nutrient loading to the sea. Assuming unchanged river nutrient concentrations, we evaluate the effects of changing runoff on commitments to nutrient reductions under the Baltic Sea Action Plan. For several countries, climate projections point to large variability in load changes in relation to reduction targets. These changes either increase loads, making the target more difficult to reach, or decrease them, leading instead to a full achievement of the target. The impact of variability in climate projections varies with the size of the reduction target and is larger for countriesmore » with more limited commitments. Finally, in the end, a number of focused actions are needed to manage the effects of climate change on nutrient loads: reducing uncertainty in climate projections, deciding on frameworks to identify best performing models with respect to land surface hydrology, and increasing efforts at sustained monitoring of water flow changes.« less

COUPLING BETWEEN THE COASTAL OCEAN AND YAQUINA BAY, OREGON: THE IMPORTANCE OF OCEANIC INPUTS RELATIVE TO OTHER NITROGEN SOURCES

EPA Science Inventory

Understanding of the role of oceanic input in nutrient loadings is important for understanding nutrient and phytoplankton dynamics in estuaries adjacent to coastal upwelling regions as well as determining the natural background conditions. We examined the nitrogen sources to Yaqu...

Spatial and temporal changes of water quality, and SWAT modeling of Vosvozis river basin, North Greece.

PubMed

Boskidis, Ioannis; Gikas, Georgios D; Pisinaras, Vassilios; Tsihrintzis, Vassilios A

2010-09-01

The results of an investigation of the quantitative and qualitative characteristics of Vosvozis river in Northern Greece is presented. For the purposes of this study, three gaging stations were installed along Vosvozis river, where water quantity and quality measurements were conducted for the period August 2005 to November 2006. Water discharge, temperature, pH, dissolved oxygen (DO) and electrical conductivity (EC) were measured in situ using appropriate equipment. The collected water samples were analyzed in the laboratory for the determination of nitrate, nitrite and ammonium nitrogen, total Kjeldalh nitrogen (TKN), orthophosphate (OP), total phosphorus (TP), COD, and BOD. Agricultural diffuse sources provided the major source of nitrate nitrogen loads during the wet period. During the dry period (from June to October), the major nutrient (N, P) and COD, BOD sources were point sources. The trophic status of Vosvozis river during the monitoring period was determined as eutrophic, based on Dodds classification scheme. Moreover, the SWAT model was used to simulate hydrographs and nutrient loads. SWAT was validated with the measured data. Predicted hydrographs and pollutographs were plotted against observed values and showed good agreement. The validated model was used to test eight alternative scenarios concerning different cropping management approaches. The results of these scenarios indicate that nonpoint source pollution is the prevailing type of pollution in the study area. The SWAT model was found to satisfactorily simulate processes in ephemeral river basins and is an effective tool in water resources management.

Micro and Macroscale Drivers of Nutrient Concentrations in Urban Streams in South, Central and North America.

PubMed

Loiselle, Steven A; Gasparini Fernandes Cunha, Davi; Shupe, Scott; Valiente, Elsa; Rocha, Luciana; Heasley, Eleanore; Belmont, Patricia Pérez; Baruch, Avinoam

Global metrics of land cover and land use provide a fundamental basis to examine the spatial variability of human-induced impacts on freshwater ecosystems. However, microscale processes and site specific conditions related to bank vegetation, pollution sources, adjacent land use and water uses can have important influences on ecosystem conditions, in particular in smaller tributary rivers. Compared to larger order rivers, these low-order streams and rivers are more numerous, yet often under-monitored. The present study explored the relationship of nutrient concentrations in 150 streams in 57 hydrological basins in South, Central and North America (Buenos Aires, Curitiba, São Paulo, Rio de Janeiro, Mexico City and Vancouver) with macroscale information available from global datasets and microscale data acquired by trained citizen scientists. Average sub-basin phosphate (P-PO4) concentrations were found to be well correlated with sub-basin attributes on both macro and microscales, while the relationships between sub-basin attributes and nitrate (N-NO3) concentrations were limited. A phosphate threshold for eutrophic conditions (>0.1 mg L-1 P-PO4) was exceeded in basins where microscale point source discharge points (eg. residential, industrial, urban/road) were identified in more than 86% of stream reaches monitored by citizen scientists. The presence of bankside vegetation covaried (rho = -0.53) with lower phosphate concentrations in the ecosystems studied. Macroscale information on nutrient loading allowed for a strong separation between basins with and without eutrophic conditions. Most importantly, the combination of macroscale and microscale information acquired increased our ability to explain sub-basin variability of P-PO4 concentrations. The identification of microscale point sources and bank vegetation conditions by citizen scientists provided important information that local authorities could use to improve their management of lower order river ecosystems.

Micro and Macroscale Drivers of Nutrient Concentrations in Urban Streams in South, Central and North America

PubMed Central

Loiselle, Steven A.; Gasparini Fernandes Cunha, Davi; Shupe, Scott; Valiente, Elsa; Rocha, Luciana; Heasley, Eleanore; Belmont, Patricia Pérez; Baruch, Avinoam

2016-01-01

Global metrics of land cover and land use provide a fundamental basis to examine the spatial variability of human-induced impacts on freshwater ecosystems. However, microscale processes and site specific conditions related to bank vegetation, pollution sources, adjacent land use and water uses can have important influences on ecosystem conditions, in particular in smaller tributary rivers. Compared to larger order rivers, these low-order streams and rivers are more numerous, yet often under-monitored. The present study explored the relationship of nutrient concentrations in 150 streams in 57 hydrological basins in South, Central and North America (Buenos Aires, Curitiba, São Paulo, Rio de Janeiro, Mexico City and Vancouver) with macroscale information available from global datasets and microscale data acquired by trained citizen scientists. Average sub-basin phosphate (P-PO4) concentrations were found to be well correlated with sub-basin attributes on both macro and microscales, while the relationships between sub-basin attributes and nitrate (N-NO3) concentrations were limited. A phosphate threshold for eutrophic conditions (>0.1 mg L-1 P-PO4) was exceeded in basins where microscale point source discharge points (eg. residential, industrial, urban/road) were identified in more than 86% of stream reaches monitored by citizen scientists. The presence of bankside vegetation covaried (rho = –0.53) with lower phosphate concentrations in the ecosystems studied. Macroscale information on nutrient loading allowed for a strong separation between basins with and without eutrophic conditions. Most importantly, the combination of macroscale and microscale information acquired increased our ability to explain sub-basin variability of P-PO4 concentrations. The identification of microscale point sources and bank vegetation conditions by citizen scientists provided important information that local authorities could use to improve their management of lower order river ecosystems. PMID:27662192

Using CSLD Method to Calculate COD Pollution Load of Wei River Watershed above Huaxian Section, China

NASA Astrophysics Data System (ADS)

Zhu, Lei; Song, JinXi; Liu, WanQing

2017-12-01

Huaxian Section is the last hydrological and water quality monitoring section of Weihe River Watershed. Weihe River Watershed above Huaxian Section is taken as the research objective in this paper and COD is chosen as the water quality parameter. According to the discharge characteristics of point source pollutions and non-point source pollutions, a new method to estimate pollution loads—characteristic section load(CSLD) method is suggested and point source pollution and non-point source pollution loads of Weihe River Watershed above Huaxian Section are calculated in the rainy, normal and dry season in the year 2007. The results show that the monthly point source pollution loads of Weihe River Watershed above Huaxian Section discharge stably and the monthly non-point source pollution loads of Weihe River Watershed above Huaxian Section change greatly and the non-point source pollution load proportions of total pollution load of COD decrease in the normal, rainy and wet period in turn.

Calculating NH3-N pollution load of wei river watershed above Huaxian section using CSLD method

NASA Astrophysics Data System (ADS)

Zhu, Lei; Song, JinXi; Liu, WanQing

2018-02-01

Huaxian Section is the last hydrological and water quality monitoring section of Weihe River Watershed. So it is taken as the research objective in this paper and NH3-N is chosen as the water quality parameter. According to the discharge characteristics of point source pollutions and non-point source pollutions, a new method to estimate pollution loads—characteristic section load (CSLD)method is suggested and point source pollution and non-point source pollution loads of Weihe River Watershed above Huaxian Section are calculated in the rainy, normal and dry season in the year 2007. The results show that the monthly point source pollution loads of Weihe River Watershed above Huaxian Section discharge stably and the monthly non-point source pollution loads of Weihe River Watershed above Huaxian Section change greatly. The non-point source pollution load proportions of total pollution load of NH3-N decrease in the normal, rainy and wet period in turn.

Seasonal sediment and nutrients transport patterns

USDA-ARS?s Scientific Manuscript database

It is essential to understand sediment and nutrient sources and their spatial and temporal patterns in order to design effective mitigation strategies. However, long-term data sets to determine sediment and nutrient loadings are scarce and expensive to collect. The goal of this study was to determin...

Feasibility of Estimating Relative Nutrient Contributions of Agriculture and Forests Using MODIS Time Series

NASA Technical Reports Server (NTRS)

Ross, Kenton W.; Gasser, Gerald; Spiering, Bruce

2010-01-01

Around the Gulf of Mexico, high-input crops in several regions make a significant contribution to nutrient loading of small to medium estuaries and to the near-shore Gulf. Some crops cultivated near the coast include sorghum in Texas, rice in Texas and Louisiana, sugarcane in Florida and Louisiana, citrus orchards in Florida, pecan orchards in Mississippi and Alabama, and heavy sod and ornamental production around Mobile and Tampa Bay. In addition to crops, management of timberlands in proximity to the coasts also plays a role in nutrient loading. In the summer of 2008, a feasibility project is planned to explore the use of NASA data to enhance the spatial and temporal resolution of near-coast nutrient source information available to the coastal community. The purpose of this project is to demonstrate the viability of nutrient source information products applicable to small to medium watersheds surrounding the Gulf of Mexico. Conceptually, these products are intended to complement estuarine nutrient monitoring.

Feasibility of Estimating Relative Nutrient Contributions of Agriculture using MODIS Time Series

NASA Technical Reports Server (NTRS)

Ross, Kenton W.; Gasser, Gerald; Spiering, Bruce

2008-01-01

Around the Gulf of Mexico, high-input crops in several regions make a significant contribution to nutrient loading of small to medium estuaries and to the near-shore Gulf. Some crops cultivated near the coast include sorghum in Texas, rice in Texas and Louisiana, sugarcane in Florida and Louisiana, citrus orchards in Florida, pecan orchards in Mississippi and Alabama, and heavy sod and ornamental production around Mobile and Tampa Bay. In addition to crops, management of timberlands in proximity to the coasts also plays a role in nutrient loading. In the summer of 2008, a feasibility project is planned to explore the use of NASA data to enhance the spatial and temporal resolution of near-coast nutrient source information available to the coastal community. The purpose of this project is to demonstrate the viability of nutrient source information products applicable to small to medium watersheds surrounding the Gulf of Mexico. Conceptually, these products are intended to complement estuarine nutrient monitoring.

Contribution of Wastewater Treatment Plant Effluents to Nutrient Dynamics in Aquatic Systems: A Review

NASA Astrophysics Data System (ADS)

Carey, Richard O.; Migliaccio, Kati W.

2009-08-01

Excessive nutrient loading (considering nitrogen and phosphorus) is a major ongoing threat to water quality and here we review the impact of nutrient discharges from wastewater treatment plants (WWTPs) to United States (U.S.) freshwater systems. While urban and agricultural land uses are significant nonpoint nutrient contributors, effluent from point sources such as WWTPs can overwhelm receiving waters, effectively dominating hydrological characteristics and regulating instream nutrient processes. Population growth, increased wastewater volumes, and sustainability of critical water resources have all been key factors influencing the extent of wastewater treatment. Reducing nutrient concentrations in wastewater is an important aspect of water quality management because excessive nutrient concentrations often prevent water bodies from meeting designated uses. WWTPs employ numerous physical, chemical, and biological methods to improve effluent water quality but nutrient removal requires advanced treatment and infrastructure that may be economically prohibitive. Therefore, effluent nutrient concentrations vary depending on the particular processes used to treat influent wastewater. Increasingly stringent regulations regarding nutrient concentrations in discharged effluent, along with greater freshwater demand in populous areas, have led to the development of extensive water recycling programs within many U.S. regions. Reuse programs provide an opportunity to reduce or eliminate direct nutrient discharges to receiving waters while allowing for the beneficial use of reclaimed water. However, nutrients in reclaimed water can still be a concern for reuse applications, such as agricultural and landscape irrigation.

Future nutrient load scenarios for the Baltic Sea due to climate and lifestyle changes.

PubMed

Hägg, Hanna Eriksson; Lyon, Steve W; Wällstedt, Teresia; Mörth, Carl-Magnus; Claremar, Björn; Humborg, Christoph

2014-04-01

Dynamic model simulations of the future climate and projections of future lifestyles within the Baltic Sea Drainage Basin (BSDB) were considered in this study to estimate potential trends in future nutrient loads to the Baltic Sea. Total nitrogen and total phosphorus loads were estimated using a simple proxy based only on human population (to account for nutrient sources) and stream discharges (to account for nutrient transport). This population-discharge proxy provided a good estimate for nutrient loads across the seven sub-basins of the BSDB considered. All climate scenarios considered here produced increased nutrient loads to the Baltic Sea over the next 100 years. There was variation between the climate scenarios such that sub-basin and regional differences were seen in future nutrient runoff depending on the climate model and scenario considered. Regardless, the results of this study indicate that changes in lifestyle brought about through shifts in consumption and population potentially overshadow the climate effects on future nutrient runoff for the entire BSDB. Regionally, however, lifestyle changes appear relatively more important in the southern regions of the BSDB while climatic changes appear more important in the northern regions with regards to future increases in nutrient loads. From a whole-ecosystem management perspective of the BSDB, this implies that implementation of improved and targeted management practices can still bring about improved conditions in the Baltic Sea in the face of a warmer and wetter future climate.

Sources of nitrogen and phosphorus emissions to Irish rivers: estimates from the Source Load Apportionment Model (SLAM)

NASA Astrophysics Data System (ADS)

Mockler, Eva; Deakin, Jenny; Archbold, Marie; Daly, Donal; Bruen, Michael

2017-04-01

More than half of the river and lake water bodies in Europe are at less than good ecological status or potential, and diffuse pollution from agriculture remains a major, but not the only, cause of this poor performance. In Ireland, it is evident that agri-environmental policy and land management practices have, in many areas, reduced nutrient emissions to water, mitigating the potential impact on water quality. However, additional measures may be required in order to further decouple the relationship between agricultural productivity and emissions to water, which is of vital importance given the on-going agricultural intensification in Ireland. Catchment management can be greatly supported by modelling, which can reduce the resources required to analyse large amounts of information and can enable investigations and measures to be targeted. The Source Load Apportionment Model (SLAM) framework was developed to support catchment management in Ireland by characterising the contributions from various sources of phosphorus (P) and nitrogen (N) emissions to water. The SLAM integrates multiple national spatial datasets relating to nutrient emissions to surface water, including land use and physical characteristics of the sub-catchments to predict emissions from point (wastewater, industry discharges and septic tank systems) and diffuse sources (agriculture, forestry, peatlands, etc.). The annual nutrient emissions predicted by the SLAM were assessed against nutrient monitoring data for 16 major river catchments covering 50% of the area of Ireland. At national scale, results indicate that the total average annual emissions to surface water in Ireland are over 2,700 t yr-1 of P and 80,000 t yr-1 of N. The SLAM results include the proportional contributions from individual sources at a range of scales from sub-catchment to national, and show that the main sources of P are from wastewater and agriculture, with wide variations across the country related to local anthropogenic pressures and the hydrogeological setting. Agriculture is the main source of N emissions to water across all regions of Ireland. The SLAM results have been incorporated into an Integrated Catchment Management process and used in conjunction with monitoring data and local knowledge during the characterisation of all Irish water bodies by the Environmental Protection Agency. This demonstrates the successful integration of research into catchment management to inform the identification of (i) the sources of nutrients at regional and local scales and (ii) the potential significant pressures and appropriate mitigation measures.

Integrating Spatial Land Use Analysis and Mathematical Material Flow Analysis for Nutrient Management: A Case Study of the Bang Pakong River Basin in Thailand

NASA Astrophysics Data System (ADS)

Kupkanchanakul, Wallapa; Kwonpongsagoon, Suphaphat; Bader, Hans-Peter; Scheidegger, Ruth

2015-05-01

Rivers in developing and emerging countries often lack good water quality. Tools to assess the water quality in rivers, including identification of possible sources of pollution, are therefore of increasing importance. The aim of this study is to apply mathematical material flow and spatial land use analyses to identify and geographically locate the main nitrogen and phosphorus sources and processes in Bang Pakong Basin (BPB). Potential measures to mitigate the nitrogen and phosphorus loads to the water system can then be efficiently evaluated. The combination of these two methods reveals the overall nutrient load as well as local "hot spots." This allows possible mitigation measures to be discussed with regard to their spatial location. This approach goes beyond previous work in which mathematical material flow analysis was shown to be a useful tool to investigate sources of nutrients regardless of their location. The results show that the main sources contributing nutrients to waterways are aquaculture, such as shrimp, tilapia, catfish, and sea bass farming, as well as rice paddies along the main river. Additional sources contributing nutrients to this basin are field crops, livestock, aquaculture, households, and industry. High levels of nutrient inflows come from feeds and fertilizers through aquaculture and rice cultivation. The excess nutrients run into the waterways by direct discharge from aquaculture and runoff processes from rice paddies. Scenario analysis shows that management practices for aquaculture, rice, pig, and poultry farming are key drivers for reducing nutrients in the BPB.

Integrating spatial land use analysis and mathematical material flow analysis for nutrient management: a case study of the Bang Pakong River Basin in Thailand.

PubMed

Kupkanchanakul, Wallapa; Kwonpongsagoon, Suphaphat; Bader, Hans-Peter; Scheidegger, Ruth

2015-05-01

Rivers in developing and emerging countries often lack good water quality. Tools to assess the water quality in rivers, including identification of possible sources of pollution, are therefore of increasing importance. The aim of this study is to apply mathematical material flow and spatial land use analyses to identify and geographically locate the main nitrogen and phosphorus sources and processes in Bang Pakong Basin (BPB). Potential measures to mitigate the nitrogen and phosphorus loads to the water system can then be efficiently evaluated. The combination of these two methods reveals the overall nutrient load as well as local "hot spots." This allows possible mitigation measures to be discussed with regard to their spatial location. This approach goes beyond previous work in which mathematical material flow analysis was shown to be a useful tool to investigate sources of nutrients regardless of their location. The results show that the main sources contributing nutrients to waterways are aquaculture, such as shrimp, tilapia, catfish, and sea bass farming, as well as rice paddies along the main river. Additional sources contributing nutrients to this basin are field crops, livestock, aquaculture, households, and industry. High levels of nutrient inflows come from feeds and fertilizers through aquaculture and rice cultivation. The excess nutrients run into the waterways by direct discharge from aquaculture and runoff processes from rice paddies. Scenario analysis shows that management practices for aquaculture, rice, pig, and poultry farming are key drivers for reducing nutrients in the BPB.

Changing Regulations of COD Pollution Load of Weihe River Watershed above TongGuan Section, China

NASA Astrophysics Data System (ADS)

Zhu, Lei; Liu, WanQing

2018-02-01

TongGuan Section of Weihe River Watershed is a provincial section between Shaanxi Province and Henan Province, China. Weihe River Watershed above TongGuan Section is taken as the research objective in this paper and COD is chosen as the water quality parameter. According to the discharge characteristics of point source pollutions and non-point source pollutions, a method—characteristic section load (CSLD) method is suggested and point and non-point source pollution loads of Weihe River Watershed above TongGuan Section are calculated in the rainy, normal and dry season in 2013. The results show that the monthly point source pollution loads of Weihe River Watershed above TongGuan Section discharge stably and the monthly non-point source pollution loads of Weihe River Watershed above TongGuan Section change greatly and the non-point source pollution load proportions of total pollution load of COD decrease in the rainy, wet and normal period in turn.

Subterranean Groundwater Nutrient Input to Coastal Oceans and Coral Reef Sustainability

NASA Astrophysics Data System (ADS)

Paytan, A.; Street, J. H.

2003-12-01

Coral reefs are often referred to as the tropical rain forests of the oceans because of their high productivity and biodiversity. Recent observations in coral reefs worldwide have shown clear degradation in water quality and coral reef health and diversity. The implications of this are severe, including tremendous economic losses mostly though fishing and tourism. Nutrient loading has been implicated as one possible cause for the ecosystem decline. A previously unappreciated potential source of nutrient loading is submarine ground water discharge (SGW). Ground water in many cases has high nutrient content from sewage pollution and fertilizer application for agriculture and landscaping. To better understand the effect of this potential source of nutrient input and degrading water quality, we are exploring the contribution of SGW to the nutrient levels in coral reefs. A key to this approach is determining the amount and source of SGW that flows into the coast as well as its nutrient concentrations. The SGW flux and associated input of chemical dissolved load (nutrient, DOC, trace elements and other contaminants) is quantified using naturally occurring Ra isotopes. Radium isotopes have been shown to be excellent tracers for SGW inputs into estuaries and coastal areas (Moore, 1996; Hussain et al., 1999; Kerst et al., 2000). Measurements of Ra activity within the coral reef, the lagoons and the open waters adjacent to the reef provide valuable information regarding the input of Ra as well as nutrients and possibly pollutant from groundwater discharge. Through this analysis the effect of SGD on the delicate carbon and nutrient balance of the fragile coral reef ecosystem could be evaluated. In addition to quantifying the contribution of freshwater to the nutrient mass balance in the reef, information regarding the length of time a water parcel has remained in the near-shore region over the reef can be estimated using the Ra isotope quartet.

Groundwater – The disregarded component in lake water and nutrient budgets. Part 2: effects of groundwater on nutrients

USGS Publications Warehouse

Lewandowski, Jörg; Meinikmann, Karin; Nützmann, Gunnar; Rosenberry, Donald O.

2015-01-01

Lacustrine groundwater discharge (LGD) transports nutrients from a catchment to a lake, which may fuel eutrophication, one of the major threats to our fresh waters. Unfortunately, LGD has often been disregarded in lake nutrient studies. Most measurement techniques are based on separate determinations of volume and nutrient concentration of LGD: Loads are calculated by multiplying seepage volumes by concentrations of exfiltrating water. Typically low phosphorus (P) concentrations of pristine groundwater often are increased due to anthropogenic sources such as fertilizer, manure or sewage. Mineralization of naturally present organic matter might also increase groundwater P. Reducing redox conditions favour P transport through the aquifer to the reactive aquifer-lake interface. In some cases, large decreases of P concentrations may occur at the interface, for example, due to increased oxygen availability, while in other cases, there is nearly no decrease in P. The high reactivity of the interface complicates quantification of groundwater-borne P loads to the lake, making difficult clear differentiation of internal and external P loads to surface water. Anthropogenic sources of nitrogen (N) in groundwater are similar to those of phosphate. However, the environmental fate of N differs fundamentally from P because N occurs in several different redox states, each with different mobility. While nitrate behaves essentially conservatively in most oxic aquifers, ammonium's mobility is similar to that of phosphate. Nitrate may be transformed to gaseous N2 in reducing conditions and permanently removed from the system. Biogeochemical turnover of N is common at the reactive aquifer-lake interface. Nutrient loads from LGD were compiled from the literature. Groundwater-borne P loads vary from 0.74 to 2900 mg PO4-P m−2 year−1; for N, these loads vary from 0.001 to 640 g m−2 year−1. Even small amounts of seepage can carry large nutrient loads due to often high nutrient concentrations in groundwater. Large spatial heterogeneity, uncertain areal extent of the interface and difficult accessibility make every determination of LGD a challenge. However, determinations of LGD are essential to effective lake management.

The effect of nitrogen loading on a brackish estuarine faunal community: A stable isotope approach

USGS Publications Warehouse

Keats, R.A.; Osher, L.J.; Neckles, H.A.

2004-01-01

Coastal ecosystems worldwide face increased nutrient enrichment from shoreline and watershed development and atmospheric pollution. We investigated the response of the faunal community of a small microtidal estuary dominated by Ruppia maritima (widgeon grass) in Maine, United States, to increased nitrogen loading using an in situ mesocosm enrichment experiment. Community response was characterized by assessing quantitative shifts in macroin-vertebrate community composition and identifying changes in food web structure using stable carbon and nitrogen isotope ratios of producers and consumers. The community was dominated by brackish water invertebrates including midge larvae, oligochaetes, damselfly larvae, amphipods, and ostracods. Experimental nutrient additions resulted in significantly lower densities of herbivorous chironomids and predatory damselflies and greater densities of deposit feeding oligochaetes. Grazing midge larvae (Chironomidae: Dicrotendipes, Cricotopus) consumed epiphytic algae under both natural and enriched conditions. Deposit feeding Chironomus was dependent on allochthonous sources of detritus under natural conditions and exhibited a shift to autochthonous sources of detritus under enriched conditions. Predatory Enallagma primarily consumed grazing chironomids under all but the highest loading conditions. Experimental nutrient loading resulted in an increase in generalist deposit feeders dependent on autochthonous sources of detritus.

Data to support statistical modeling of instream nutrient load based on watershed attributes, southeastern United States, 2002

USGS Publications Warehouse

Hoos, Anne B.; Terziotti, Silvia; McMahon, Gerard; Savvas, Katerina; Tighe, Kirsten C.; Alkons-Wolinsky, Ruth

2008-01-01

This report presents and describes the digital datasets that characterize nutrient source inputs, environmental characteristics, and instream nutrient loads for the purpose of calibrating and applying a nutrient water-quality model for the southeastern United States for 2002. The model area includes all of the river basins draining to the south Atlantic and the eastern Gulf of Mexico, as well as the Tennessee River basin (referred to collectively as the SAGT area). The water-quality model SPARROW (SPAtially-Referenced Regression On Watershed attributes), developed by the U.S. Geological Survey, uses a regression equation to describe the relation between watershed attributes (predictors) and measured instream loads (response). Watershed attributes that are considered to describe nutrient input conditions and are tested in the SPARROW model for the SAGT area as source variables include atmospheric deposition, fertilizer application to farmland, manure from livestock production, permitted wastewater discharge, and land cover. Watershed and channel attributes that are considered to affect rates of nutrient transport from land to water and are tested in the SAGT SPARROW model as nutrient-transport variables include characteristics of soil, landform, climate, reach time of travel, and reservoir hydraulic loading. Datasets with estimates of each of these attributes for each individual reach or catchment in the reach-catchment network are presented in this report, along with descriptions of methods used to produce them. Measurements of nutrient water quality at stream monitoring sites from a combination of monitoring programs were used to develop observations of the response variable - mean annual nitrogen or phosphorus load - in the SPARROW regression equation. Instream load of nitrogen and phosphorus was estimated using bias-corrected log-linear regression models using the program Fluxmaster, which provides temporally detrended estimates of long-term mean load well-suited for spatial comparisons. The detrended, or normalized, estimates of load are useful for regional-scale assessments but should be used with caution for local-scale interpretations, for which use of loads estimated for actual time periods and employing more detailed regression analysis is suggested. The mean value of the nitrogen yield estimates, normalized to 2002, for 637 stations in the SAGT area is 4.7 kilograms per hectare; the mean value of nitrogen flow-weighted mean concentration is 1.2 milligrams per liter. The mean value of the phosphorus yield estimates, normalized to 2002, for the 747 stations in the SAGT area is 0.66 kilogram per hectare; the mean value of phosphorus flow-weighted mean concentration is 0.17 milligram per liter. Nutrient conditions measured in streams affected by substantial influx or outflux of water and nutrient mass across surface-water basin divides do not reflect nutrient source and transport conditions in the topographic watershed; therefore, inclusion of such streams in the SPARROW modeling approach is considered inappropriate. River basins identified with this concern include south Florida (where surface-water flow paths have been extensively altered) and the Oklawaha, Crystal, Lower Sante Fe, Lower Suwanee, St. Marks, and Chipola River basins in central and northern Florida (where flow exchange with the underlying regional aquifer may represent substantial nitrogen influx to and outflux from the surface-water basins).

Identification of watershed priority management areas under water quality constraints: A simulation-optimization approach with ideal load reduction

NASA Astrophysics Data System (ADS)

Dong, Feifei; Liu, Yong; Wu, Zhen; Chen, Yihui; Guo, Huaicheng

2018-07-01

Targeting nonpoint source (NPS) pollution hot spots is of vital importance for placement of best management practices (BMPs). Although physically-based watershed models have been widely used to estimate nutrient emissions, connections between nutrient abatement and compliance of water quality standards have been rarely considered in NPS hotspot ranking, which may lead to ineffective decision-making. It's critical to develop a strategy to identify priority management areas (PMAs) based on water quality response to nutrient load mitigation. A water quality constrained PMA identification framework was thereby proposed in this study, based on the simulation-optimization approach with ideal load reduction (ILR-SO). It integrates the physically-based Soil and Water Assessment Tool (SWAT) model and an optimization model under constraints of site-specific water quality standards. To our knowledge, it was the first effort to identify PMAs with simulation-based optimization. The SWAT model was established to simulate temporal and spatial nutrient loading and evaluate effectiveness of pollution mitigation. A metamodel was trained to establish a quantitative relationship between sources and water quality. Ranking of priority areas is based on required nutrient load reduction in each sub-watershed targeting to satisfy water quality standards in waterbodies, which was calculated with genetic algorithm (GA). The proposed approach was used for identification of PMAs on the basis of diffuse total phosphorus (TP) in Lake Dianchi Watershed, one of the three most eutrophic large lakes in China. The modeling results demonstrated that 85% of diffuse TP came from 30% of the watershed area. Compared with the two conventional targeting strategies based on overland nutrient loss and instream nutrient loading, the ILR-SO model identified distinct PMAs and narrowed down the coverage of management areas. This study addressed the urgent need to incorporate water quality response into PMA identification and showed that the ILR-SO approach is effective to guide watershed management for aquatic ecosystem restoration.

A modification of the Regional Nutrient Management model (ReNuMa) to identify long-term changes in riverine nitrogen sources

NASA Astrophysics Data System (ADS)

Hu, Minpeng; Liu, Yanmei; Wang, Jiahui; Dahlgren, Randy A.; Chen, Dingjiang

2018-06-01

Source apportionment is critical for guiding development of efficient watershed nitrogen (N) pollution control measures. The ReNuMa (Regional Nutrient Management) model, a semi-empirical, semi-process-oriented model with modest data requirements, has been widely used for riverine N source apportionment. However, the ReNuMa model contains limitations for addressing long-term N dynamics by ignoring temporal changes in atmospheric N deposition rates and N-leaching lag effects. This work modified the ReNuMa model by revising the source code to allow yearly changes in atmospheric N deposition and incorporation of N-leaching lag effects into N transport processes. The appropriate N-leaching lag time was determined from cross-correlation analysis between annual watershed individual N source inputs and riverine N export. Accuracy of the modified ReNuMa model was demonstrated through analysis of a 31-year water quality record (1980-2010) from the Yongan watershed in eastern China. The revisions considerably improved the accuracy (Nash-Sutcliff coefficient increased by ∼0.2) of the modified ReNuMa model for predicting riverine N loads. The modified model explicitly identified annual and seasonal changes in contributions of various N sources (i.e., point vs. nonpoint source, surface runoff vs. groundwater) to riverine N loads as well as the fate of watershed anthropogenic N inputs. Model results were consistent with previously modeled or observed lag time length as well as changes in riverine chloride and nitrate concentrations during the low-flow regime and available N levels in agricultural soils of this watershed. The modified ReNuMa model is applicable for addressing long-term changes in riverine N sources, providing decision-makers with critical information for guiding watershed N pollution control strategies.

Nutrient additions by waterfowl to lakes and reservoirs: predicting their effects on productivity and water quality

USGS Publications Warehouse

Manny, Bruce A.; Johnson, W.C.; Wetzel, R.G.

1994-01-01

Lakes and reservoirs provide water for human needs and habitat for aquatic birds. Managers of such waters may ask whether nutrients added by waterfowl degrade water quality. For lakes and reservoirs where primary productivity is limited by phosphorus (P), we developed a procedure that integrates annual P loads from waterfowl and other external sources, applies a nutrient load-response model, and determines whether waterfowl that used the lake or reservoir degraded water quality. Annual P loading by waterfowl can be derived from a figure in this report, using the days per year that each kind spent on any lake or reservoir. In our example, over 6500 Canada geese (Branta canadensis) and 4200 ducks (mostly mallards, Anas platyrhynchos) added 4462 kg of carbon (C), 280 kg of nitrogen (N), and 88 kg of P y-1 to Wintergreen Lake in southwestern Michigan, mostly during their migration. These amounts were 69% of all C, 27% of all N, and 70% of all P that entered the lake from external sources. Loads from all external sources totaled 840 mg P m-2 y-1. Application of a nutrient load-response model to this concentration, the hydraulic load (0.25 m y-1), and the water residence time (9.7 y) of Wintergreen Lake yielded an average annual concentration of total P in the lake of 818 mg m-3 that classified the lake as hypertrophic. This trophic classification agreed with independent measures of primary productivity, chlorophyll-a, total P, total N, and Secchi disk transparency made in Wintergreen Lake. Our procedure showed that waterfowl caused low water quality in Wintergreen Lake.

Management Practices Used in Agricultural Drainage Ditches to Reduce Gulf of Mexico Hypoxia.

PubMed

Faust, Derek R; Kröger, Robert; Moore, Matthew T; Rush, Scott A

2018-01-01

Agricultural non-point sources of nutrients and sediments have caused eutrophication and other water quality issues in aquatic and marine ecosystems, such as the annual occurrence of hypoxia in the Gulf of Mexico. Management practices have been implemented adjacent to and in agricultural drainage ditches to promote their wetland characteristics and functions, including reduction of nitrogen, phosphorus, and sediment losses downstream. This review: (1) summarized studies examining changes in nutrient and total suspended solid concentrations and loads associated with management practices in drainage ditches (i.e., riser and slotted pipes, two-stage ditches, vegetated ditches, low-grade weirs, and organic carbon amendments) with emphasis on the Lower Mississippi Alluvial Valley, (2) quantified management system effects on nutrient and total suspended solid concentrations and loads and, (3) identified information gaps regarding water quality associated with these management practices and research needs in this area. In general, management practices used in drainage ditches at times reduced losses of total suspended solids, N, and P. However, management practices were often ineffective during storm events that were uncommon and intense in duration and volume, although these types of events could increase in frequency and intensity with climate change. Studies on combined effects of management practices on drainage ditch water quality, along with research towards improved nutrient and sediment reduction efficiency during intense storm events are urgently needed.

Runoff characteristics and non-point source pollution analysis in the Taihu Lake Basin: a case study of the town of Xueyan, China.

PubMed

Zhu, Q D; Sun, J H; Hua, G F; Wang, J H; Wang, H

2015-10-01

Non-point source pollution is a significant environmental issue in small watersheds in China. To study the effects of rainfall on pollutants transported by runoff, rainfall was monitored in Xueyan town in the Taihu Lake Basin (TLB) for over 12 consecutive months. The concentrations of different forms of nitrogen (N) and phosphorus (P), and chemical oxygen demand, were monitored in runoff and river water across different land use types. The results indicated that pollutant loads were highly variable. Most N losses due to runoff were found around industrial areas (printing factories), while residential areas exhibited the lowest nitrogen losses through runoff. Nitrate nitrogen (NO3-N) and ammonia nitrogen (NH4-N) were the dominant forms of soluble N around printing factories and hotels, respectively. The levels of N in river water were stable prior to the generation of runoff from a rainfall event, after which they were positively correlated to rainfall intensity. In addition, three sites with different areas were selected for a case study to analyze trends in pollutant levels during two rainfall events, using the AnnAGNPS model. The modeled results generally agreed with the observed data, which suggests that AnnAGNPS can be used successfully for modeling runoff nutrient loading in this region. The conclusions of this study provide important information on controlling non-point source pollution in TLB.

Evaluation of Land Use, Land Management and Soil Conservation Strategies to Reduce Non-Point Source Pollution Loads in the Three Gorges Region, China

NASA Astrophysics Data System (ADS)

Strehmel, Alexander; Schmalz, Britta; Fohrer, Nicola

2016-11-01

The construction of the Three Gorges Dam in China and the subsequent impoundment of the Yangtze River have induced a major land use change in the Three Gorges Reservoir Region, which fosters increased inputs of sediment and nutrients from diffuse sources into the water bodies. Several government programs have been implemented to mitigate high sediment and nutrient loads to the reservoir. However, institutional weaknesses and a focus on economic development have so far widely counteracted the effectiveness of these programs. In this study, the eco-hydrological model soil and water assessment tool is used to assess the effects of changes in fertilizer amounts and the conditions of bench terraces in the Xiangxi catchment in the Three Gorges Reservoir Region on diffuse matter releases. With this, the study aims at identifying efficient management measures, which should have priority. The results show that a reduction of fertilizer amounts cannot reduce phosphorus loads considerably without inhibiting crop productivity. The condition of terraces in the catchment has a strong impact on soil erosion and phosphorus releases from agricultural areas. Hence, if economically feasible, programmes focusing on the construction and maintenance of terraces in the region should be implemented. Additionally, intercropping on corn fields as well as more efficient fertilization schemes for agricultural land were identified as potential instruments to reduce diffuse matter loads further. While the study was carried out in the Three Gorges Region, its findings may also beneficial for the reduction of water pollution in other mountainous areas with strong agricultural use.

Evaluation of Land Use, Land Management and Soil Conservation Strategies to Reduce Non-Point Source Pollution Loads in the Three Gorges Region, China.

PubMed

Strehmel, Alexander; Schmalz, Britta; Fohrer, Nicola

2016-11-01

The construction of the Three Gorges Dam in China and the subsequent impoundment of the Yangtze River have induced a major land use change in the Three Gorges Reservoir Region, which fosters increased inputs of sediment and nutrients from diffuse sources into the water bodies. Several government programs have been implemented to mitigate high sediment and nutrient loads to the reservoir. However, institutional weaknesses and a focus on economic development have so far widely counteracted the effectiveness of these programs. In this study, the eco-hydrological model soil and water assessment tool is used to assess the effects of changes in fertilizer amounts and the conditions of bench terraces in the Xiangxi catchment in the Three Gorges Reservoir Region on diffuse matter releases. With this, the study aims at identifying efficient management measures, which should have priority. The results show that a reduction of fertilizer amounts cannot reduce phosphorus loads considerably without inhibiting crop productivity. The condition of terraces in the catchment has a strong impact on soil erosion and phosphorus releases from agricultural areas. Hence, if economically feasible, programmes focusing on the construction and maintenance of terraces in the region should be implemented. Additionally, intercropping on corn fields as well as more efficient fertilization schemes for agricultural land were identified as potential instruments to reduce diffuse matter loads further. While the study was carried out in the Three Gorges Region, its findings may also beneficial for the reduction of water pollution in other mountainous areas with strong agricultural use.

Source Separation of Urine as an Alternative Solution to Nutrient Management in Biological Nutrient Removal Treatment Plants.

PubMed

Jimenez, Jose; Bott, Charles; Love, Nancy; Bratby, John

2015-12-01

Municipal wastewater contains a mixture of brown (feces and toilet paper), yellow (urine), and gray (kitchen, bathroom and wash) waters. Urine contributes approximately 70-80% of the nitrogen (N), 50-70% of the phosphorus (P) load and 60-70% of the pharmaceutical residues in normal domestic sewage. This study evaluated the impact of different levels of source separation of urine on an existing biological nutrient removal (BNR) process. A process model of an existing biological nutrient removal (BNR) plant was used. Increasing the amount of urine diverted from the water reclamation facilities, has little impact on effluent ammonia (NH₃-N) concentration, but effluent nitrate (NO₃-N) concentration decreases. If nitrification is necessary then no reduction in the sludge age can be realized. However, a point is reached where the remaining influent nitrogen load matches the nitrogen requirements for biomass growth, and no residual nitrogen needs to be nitrified. That allows a significant reduction in sludge age, implying reduced process volume requirements. In situations where nitrification is required, lower effluent nitrate (NO₃-N) concentrations were realized due to both the lower influent nitrogen content in the wastewater and a more favorable nitrogen-to-carbon ratio for denitrification. The external carbon requirement for denitrification decreases as the urine separation efficiency increases due to the lower influent nitrogen content in the wastewater and a more favorable nitrogen-to-carbon ratio for denitrification. The effluent phosphorus concentration decreases when the amount of urine sent to water reclamation facilities is decreased due to lower influent phosphorus concentrations. In the case of chemical phosphate removal, urine separation reduces the amount of chemicals required.

Spatial characterization of riparian buffer effects on sediment loads from watershed systems.

PubMed

Momm, Henrique G; Bingner, Ronald L; Yuan, Yongping; Locke, Martin A; Wells, Robert R

2014-09-01

Understanding all watershed systems and their interactions is a complex, but critical, undertaking when developing practices designed to reduce topsoil loss and chemical/nutrient transport from agricultural fields. The presence of riparian buffer vegetation in agricultural landscapes can modify the characteristics of overland flow, promoting sediment deposition and nutrient filtering. Watershed simulation tools, such as the USDA-Annualized Agricultural Non-Point Source (AnnAGNPS) pollution model, typically require detailed information for each riparian buffer zone throughout the watershed describing the location, width, vegetation type, topography, and possible presence of concentrated flow paths through the riparian buffer zone. Research was conducted to develop GIS-based technology designed to spatially characterize riparian buffers and to estimate buffer efficiency in reducing sediment loads in a semiautomated fashion at watershed scale. The methodology combines modeling technology at different scales, at individual concentrated flow paths passing through the riparian zone, and at watershed scales. At the concentrated flow path scale, vegetative filter strip models are applied to estimate the sediment-trapping efficiency for each individual flow path, which are aggregated based on the watershed subdivision and used in the determination of the overall impact of the riparian vegetation at the watershed scale. This GIS-based technology is combined with AnnAGNPS to demonstrate the effect of riparian vegetation on sediment loadings from sheet and rill and ephemeral gully sources. The effects of variability in basic input parameters used to characterize riparian buffers, onto generated outputs at field scale (sediment trapping efficiency) and at watershed scale (sediment loadings from different sources) were evaluated and quantified. The AnnAGNPS riparian buffer component represents an important step in understanding and accounting for the effect of riparian vegetation, existing and/or managed, in reducing sediment loads at the watershed scale. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Review of scenario analyses to reduce agricultural nitrogen and phosphorus loading to the aquatic environment.

PubMed

Hashemi, Fatemeh; Olesen, Jørgen E; Dalgaard, Tommy; Børgesen, Christen D

2016-12-15

Nutrient loadings of nitrogen (N) and phosphorus (P) to aquatic environments are of increasing concern globally for managing ecosystems, drinking water supply and food production. There are often multiple sources of these nutrients in the landscape, and the different hydrological flow patterns within stream or river catchments have considerable influence on nutrient transport, transformation and retention processes that all eventually affect loadings to vulnerable aquatic environments. Therefore, in order to address options to reduce nutrient loadings, quantitative assessment of their effects in real catchments need to be undertaken. This involves setting up scenarios of the possible nutrient load reduction measures and quantifying their impacts via modelling. Over the recent two decades there has been a great increase in the use of scenario-based analyses of strategies to combat excessive nutrient loadings. Here we review 130 published papers extracted from Web of Science for 1995 to 2014 that have applied models to analyse scenarios of agricultural impacts on nutrients loadings at catchment scale. The review shows that scenario studies have been performed over a broad range of climatic conditions, with a large focus on measures targeting land cover/use and land management for reducing the source load of N and P in the landscape. Some of the studies considered how to manage the flows of nutrients, or how changes in the landscape may be used to influence both flows and transformation processes. Few studies have considered spatially targeting measures in the landscape, and such studies are more recent. Spatially differentiated options include land cover/use modification and application of different land management options based on catchments characteristics, cropping conditions and climatic conditions. Most of the studies used existing catchment models such as SWAT and INCA, and the choice of the models may also have influenced the setup of the scenarios. The use of stakeholders for designing scenarios and for communication of results does not seem to be a widespread practice, and it would be recommendable for future scenario studies to have a more in-depth involvement of stakeholders for the elaboration and interpretation of scenarios, in particular to enhance their relevance for farm and catchment management and to foster better policies and incentives. Copyright © 2016 Elsevier B.V. All rights reserved.

Eutrophication of Buttermilk Bay, a cape cod coastal embayment: Concentrations of nutrients and watershed nutrient budgets

NASA Astrophysics Data System (ADS)

Valiela, Ivan; Costa, Joseph E.

1988-07-01

Nutrient concentrations in Buttermilk Bay, a coastal embayment on the northern end of Buzzards Bay, MA, are higher in the nearshore where salinities are lower. This pattern suggests that freshwater sources may contribute significantly to nutrient inputs into Buttermilk Bay. To evaluate the relative importance of the various sources we estimated inputs of nutrients by each major source into the watershed and into the bay itself. Septic systems contributed about 40% of the nitrogen and phosphorus entering the watershed, with precipitation and fertilizer use adding the remainder. Groundwater transported over 85% of the nitrogen and 75% of the phosphorus entering the bay. Most nutrients entering the watershed failed to reach the bay; uptake by forests, soils, denitrification, and adsorption intercepted two-thirds of the nitrogen and nine-tenths of the phosphorus that entered the watershed. The nutrients that did reach the bay most likely originated from subsoil injections into groundwater by septic tanks, plus some leaching of fertilizers. Buttermilk Bay water has relatively low nutrient concentrations, probably because of uptake of nutrients by macrophytes and because of relatively rapid tidal flushing. Annual budgets of nutrients entering the watershed showed a low nitrogen-to-phosphorus ratio of 6, but passage of nutrients through the watershed raised N/P to 23, probably because of adsorption of PO4 during transit. The N/P ratio of water that leaves the watershed and presumably enters the bay is probably high enough to maintain active growth of nitrogenlimited coastal producers. There is a seasonal shift in N/P in the water column of Buttermilk Bay. N/P exceeded the 16∶1 Redfield ratio during midwinter; the remainder of the year N/P fell below 16∶1. This suggests that annual budgets do not provide sufficiently detailed data with which to interpret nutrient-limitation of producers. Further, some idea of water turnover is also needed to evaluate impact of loading rates. Urbanization of watersheds seems to increase loadings to nearshore environments, and to shift the nutrient loadings delivered to coastal waters to relatively high N-to-P ratios, potentially stimulating growth of nitrogen-limited primary producers.

Spatial optimization of watershed management practices for nitrogen load reduction using a modeling-optimization framework.

PubMed

Yang, Guoxiang; Best, Elly P H

2015-09-15

Best management practices (BMPs) can be used effectively to reduce nutrient loads transported from non-point sources to receiving water bodies. However, methodologies of BMP selection and placement in a cost-effective way are needed to assist watershed management planners and stakeholders. We developed a novel modeling-optimization framework that can be used to find cost-effective solutions of BMP placement to attain nutrient load reduction targets. This was accomplished by integrating a GIS-based BMP siting method, a WQM-TMDL-N modeling approach to estimate total nitrogen (TN) loading, and a multi-objective optimization algorithm. Wetland restoration and buffer strip implementation were the two BMP categories used to explore the performance of this framework, both differing greatly in complexity of spatial analysis for site identification. Minimizing TN load and BMP cost were the two objective functions for the optimization process. The performance of this framework was demonstrated in the Tippecanoe River watershed, Indiana, USA. Optimized scenario-based load reduction indicated that the wetland subset selected by the minimum scenario had the greatest N removal efficiency. Buffer strips were more effective for load removal than wetlands. The optimized solutions provided a range of trade-offs between the two objective functions for both BMPs. This framework can be expanded conveniently to a regional scale because the NHDPlus catchment serves as its spatial computational unit. The present study demonstrated the potential of this framework to find cost-effective solutions to meet a water quality target, such as a 20% TN load reduction, under different conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

LONG-TERM CHANGES IN WATERSHED NUTRIENT INPUTS AND RIVERINE EXPORTS IN THE NEUSE RIVER, NORTH CAROLINA. (U915590)

EPA Science Inventory

We compared patterns of historical watershed nutrient inputs with in-river nutrient loads for the Neuse River, NC. Basin-wide sources of both nitrogen and phosphorus have increased substantially during the past century, marked by a sharp increase in the last 10 years resulting...

A multi-agency nutrient dataset used to estimate loads, improve monitoring design, and calibrate regional nutrient SPARROW models

USGS Publications Warehouse

Saad, David A.; Schwarz, Gregory E.; Robertson, Dale M.; Booth, Nathaniel

2011-01-01

Stream-loading information was compiled from federal, state, and local agencies, and selected universities as part of an effort to develop regional SPAtially Referenced Regressions On Watershed attributes (SPARROW) models to help describe the distribution, sources, and transport of nutrients in streams throughout much of the United States. After screening, 2,739 sites, sampled by 73 agencies, were identified as having suitable data for calculating long-term mean annual nutrient loads required for SPARROW model calibration. These sites had a wide range in nutrient concentrations, loads, and yields, and environmental characteristics in their basins. An analysis of the accuracy in load estimates relative to site attributes indicated that accuracy in loads improve with increases in the number of observations, the proportion of uncensored data, and the variability in flow on observation days, whereas accuracy declines with increases in the root mean square error of the water-quality model, the flow-bias ratio, the number of days between samples, the variability in daily streamflow for the prediction period, and if the load estimate has been detrended. Based on compiled data, all areas of the country had recent declines in the number of sites with sufficient water-quality data to compute accurate annual loads and support regional modeling analyses. These declines were caused by decreases in the number of sites being sampled and data not being entered in readily accessible databases.

Agricultural and urban pollution

NASA Technical Reports Server (NTRS)

Brehmer, M. L.

1972-01-01

The degradation produced by the introduction of agricultural and urban wastes into estuarine systems, with emphasis on the Chesapeake Bay area, is discussed. The subjects presented are: (1) effects of sediment loading and (2) organic and nutrient loading problems. The impact of high turbidity on the biological life of the bay is analyzed. The sources of nutrients which produce over-enrichment of the waters and the subsequent production of phytoplankton are examined.

Organic Matter Remineralization Predominates Phosphorus Cycling in the Mid-Bay Sediments in the Chesapeake Bay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sunendra, Joshi R.; Kukkadapu, Ravi K.; Burdige, David J.

2015-05-19

The Chesapeake Bay, the largest and most productive estuary in the US, suffers from varying degrees of water quality issues fueled by both point and non–point source nutrient sources. Restoration of the bay is complicated by the multitude of nutrient sources, their variable inputs and hydrological conditions, and complex interacting factors including climate forcing. These complexities not only restrict formulation of effective restoration plans but also open up debates on accountability issues with nutrient loading. A detailed understanding of sediment phosphorus (P) dynamics enables one to identify the exchange of dissolved constituents across the sediment- water interface and aid tomore » better constrain mechanisms and processes controlling the coupling between the sediments and the overlying waters. Here we used phosphate oxygen isotope ratios (δ18Op) in concert with sediment chemistry, XRD, and Mössbauer spectroscopy on the sediment retrieved from an organic rich, sulfidic site in the meso-haline portion of the mid-bay to identify sources and pathway of sedimentary P cycling and to infer potential feedback effect on bottom water hypoxia and surface water eutrophication. Isotope data indicate that the regeneration of inorganic P from organic matter degradation (remineralization) is the predominant, if not sole, pathway for authigenic P precipitation in the mid-bay sediments. We interpret that the excess inorganic P generated by remineralization should have overwhelmed any bottom-water and/or pore-water P derived from other sources or biogeochemical processes and exceeded saturation with respect to authigenic P precipitation. It is the first research that identifies the predominance of remineralization pathway against remobilization (coupled Fe-P cycling) pathway in the Chesapeake Bay. Therefore, these results are expected to have significant implications for the current understanding of P cycling and benthic-pelagic coupling in the bay, particularly on the source and pathway of P that sustains hypoxia and supports phytoplankton growth in the surface water.« less

Regional assessments of the Nation's water quality—Improved understanding of stream nutrient sources through enhanced modeling capabilities

USGS Publications Warehouse

Preston, Stephen D.; Alexander, Richard B.; Woodside, Michael D.

2011-01-01

The U.S. Geological Survey (USGS) recently completed assessments of stream nutrients in six major regions extending over much of the conterminous United States. SPARROW (SPAtially Referenced Regressions On Watershed attributes) models were developed for each region to explain spatial patterns in monitored stream nutrient loads in relation to human activities and natural resources and processes. The model information, reported by stream reach and catchment, provides contrasting views of the spatial patterns of nutrient source contributions, including those from urban (wastewater effluent and diffuse runoff from developed land), agricultural (farm fertilizers and animal manure), and specific background sources (atmospheric nitrogen deposition, soil phosphorus, forest nitrogen fixation, and channel erosion).

Modelling of point and diffuse pollution: application of the Moneris model in the Ipojuca river basin, Pernambuco State, Brazil.

PubMed

de Lima Barros, Alessandra Maciel; do Carmo Sobral, Maria; Gunkel, Günter

2013-01-01

Emissions of pollutants and nutrients are causing several problems in aquatic ecosystems, and in general an excess of nutrients, specifically nitrogen and phosphorus, is responsible for the eutrophication process in water bodies. In most developed countries, more attention is given to diffuse pollution because problems with point pollution have already been solved. In many non-developed countries basic data for point and diffuse pollution are not available. The focus of the presented studies is to quantify nutrient emissions from point and diffuse sources in the Ipojuca river basin, Pernambuco State, Brazil, using the Moneris model (Modelling Nutrient Emissions in River Systems). This model has been developed in Germany and has already been implemented in more than 600 river basins. The model is mainly based on river flow, water quality and geographical information system data. According to the Moneris model results, untreated domestic sewage is the major source of nutrients in the Ipojuca river basin. The Moneris model has shown itself to be a useful tool that allows the identification and quantification of point and diffuse nutrient sources, thus enabling the adoption of measures to reduce them. The Moneris model, conducted for the first time in a tropical river basin with intermittent flow, can be used as a reference for implementation in other watersheds.

Vegetation community change points suggest that critical loads of nutrient nitrogen may be too high

NASA Astrophysics Data System (ADS)

Wilkins, Kayla; Aherne, Julian; Bleasdale, Andy

2016-12-01

It is widely accepted that elevated nitrogen deposition can have detrimental effects on semi-natural ecosystems, including changes to plant diversity. Empirical critical loads of nutrient nitrogen have been recommended to protect many sensitive European habitats from significant harmful effects. In this study, we used Threshold Indicator Taxa Analysis (TITAN) to investigate shifts in vegetation communities along an atmospheric nitrogen deposition gradient for twenty-two semi-natural habitat types (as described under Annex I of the European Union Habitats Directive) in Ireland. Significant changes in vegetation community, i.e., change points, were determined for twelve habitats, with seven habitats showing a decrease in the number of positive indicator species. Community-level change points indicated a decrease in species abundance along a nitrogen deposition gradient ranging from 3.9 to 15.3 kg N ha-1 yr-1, which were significantly lower than recommended critical loads (Wilcoxon signed-rank test; V = 6, p < 0.05). These results suggest that lower critical loads of empirical nutrient nitrogen deposition may be required to protect many European habitats. Changes to vegetation communities may mean a loss of sensitive indicator species and potentially rare species in these habitats, highlighting how emission reductions policies set under the National Emissions Ceilings Directive may be directly linked to meeting the goal set out under the European Union's Biodiversity Strategy of "halting the loss of biodiversity" across Europe by 2020.

A comparison of drainage basin nutrient inputs with instream nutrient loads for seven rivers in Georgia and Florida, 1986-90

USGS Publications Warehouse

Asbury, C.E.; Oaksford, E.T.

1997-01-01

Instream nutrient loads of the Altamaha, Suwannee, St. Johns, Satilla, Ogeechee, Withlacoochee, and Ochlockonee River Basins were computed and compared with nutrient inputs for each basin for the period 1986-90. Nutrient constituents that were considered included nitrate, ammonia, organic nitrogen, and total phosphorus. Sources of nutrients considered for this analysis included atmospheric deposition, fertilizer, animal waste, wastewater-treatment plant discharge, and septic discharge. The mean nitrogen input ranged from 2,400 kilograms per year per square kilometer (kg/yr)km2 in the Withlacoochee River Basin to 5,470 (kg/yr)km2 in the Altamaha River Basin. The Satilla and Ochlockonee River Basins also had large amounts of nitrogen input per unit area, totaling 5,430 and 4,920 (kg/yr)km2, respectively.Fertilizer or animal waste, as sources of nitrogen, predominated in all basins. Atmospheric deposition contributed less than one-fourth of the mean total nitrogen input to all basins and was consistently the third largest input in all but the Ogeechee River Basin, where it was the second largest.The mean total phosphorus input ranged from 331 (kg/yr)km2 in the Withlacoochee River Basin to 1,380 (kg/yr)km2 in both the Altamaha and Satilla River Basins. The Ochlockonee River Basin had a phosphorus input of 1,140 (kg/yr)km2.Per unit area, the Suwannee River discharged the highest instream mean total nitrogen and phosphorus loads and also discharged higher instream nitrate loads per unit area than the other six rivers. Phosphorus loads in stream discharge were highest in the Suwannee and Ochlockonee Rivers.The ratio of nutrient outputs to inputs for the seven studied rivers ranged from 4.2 to 14.9 percent, with the St. Johns (14.9 percent) and Suwannee (12.1 percent) Rivers having significantly higher percentages than those from the other basins. The output/input percentages for mean total phosphorus ranged from 1.0 to 7.0 percent, with the St. Johns (6.2 percent) and Suwannee (7.0 percent) Rivers exporting the highest percentage of phosphorus.Although instream nutrient loads constitute only one of the various pathways nutrients may take in leaving a river basin, only a relatively small part of nutrient input to the basin leaves the basin in stream discharge for the major coastal rivers examined in this study. The actual amount of nutrient transported in a river basin depends on the ways in which nutrients are physically handled, geographically distributed, and chemically assimilated within a river basin.

Modeling of land use and reservoir effects on nonpoint source pollution in a highly agricultural basin

USGS Publications Warehouse

Wu, Yiping; Liu, Shu-Guang

2012-01-01

Nonpoint source (NPS) pollution is tightly linked to land use activities that determine the sources and magnitudes of pollutant loadings to stream water. The pollutant loads may also be alleviated within reservoirs because of the physical interception resulting from changed hydrological regimes and other biochemical processes. It is important but challenging to assess the NPS pollution processes with human effects due to the measurement limitations. The objective of this study is to evaluate the effects of human activities such as land uses and reservoir operation on the hydrological and NPS pollution processes in a highly agricultural area-the Iowa River Basin-using the Soil and Water Assessment Tool (SWAT). The evaluation of model performance at multiple sites reveals that SWAT can consistently simulate the daily streamflow, and monthly/annual sediment and nutrient loads (nitrate nitrogen and mineral phosphorus) in the basin. We also used the calibrated model to estimate the trap efficiencies of sediment (~78%) and nutrients (~30%) in the Coralville Reservoir within the basin. These non-negligible effects emphasize the significance of incorporating the sediment and nutrient removal mechanisms into watershed system studies. The spatial quantification of the critical NPS pollution loads can help identify hot-spot areas that are likely locations for the best management practices.

Modeling of land use and reservoir effects on nonpoint source pollution in a highly agricultural basin.

PubMed

Wu, Yiping; Liu, Shuguang

2012-09-01

Nonpoint source (NPS) pollution is tightly linked to land use activities that determine the sources and magnitudes of pollutant loadings to stream water. The pollutant loads may also be alleviated within reservoirs because of the physical interception resulting from changed hydrological regimes and other biochemical processes. It is important but challenging to assess the NPS pollution processes with human effects due to the measurement limitations. The objective of this study is to evaluate the effects of human activities such as land uses and reservoir operation on the hydrological and NPS pollution processes in a highly agricultural area-the Iowa River Basin-using the Soil and Water Assessment Tool (SWAT). The evaluation of model performance at multiple sites reveals that SWAT can consistently simulate the daily streamflow, and monthly/annual sediment and nutrient loads (nitrate nitrogen and mineral phosphorus) in the basin. We also used the calibrated model to estimate the trap efficiencies of sediment (∼78%) and nutrients (∼30%) in the Coralville Reservoir within the basin. These non-negligible effects emphasize the significance of incorporating the sediment and nutrient removal mechanisms into watershed system studies. The spatial quantification of the critical NPS pollution loads can help identify hot-spot areas that are likely locations for the best management practices.

Drainage Basins as Large-Scale Field Laboratories of Change: Hydro-biogeochemical- economic Model Study Support for Water Pollution and Eutrophication Management Under Uncertainty

NASA Astrophysics Data System (ADS)

Destouni, G.

2008-12-01

Excess nutrient and pollutant releases from various point and diffuse sources at and below the land surface, associated with land use, industry and households, pose serious eutrophication and pollution risks to inland and coastal water ecosystems worldwide. These risks must be assessed, for instance according to the EU Water Framework Directive (WFD). The WFD demands economically efficient, basin-scale water management for achieving and maintaining good physico-chemical and ecological status in all the inland and coastal waters of EU member states. This paper synthesizes a series of hydro-biogeochemical and linked economic efficiency studies of basin-scale waterborne nutrient and pollutant flows, the development over the last decades up to the current levels of these flows, the main monitoring and modelling uncertainties associated with their quantification, and the effectiveness and economic efficiency of different possible abatement strategies for abating them in order to meet WFD requirements and other environmental goals on local, national and international levels under climate and other regional change. The studies include different Swedish and Baltic Sea drainage basins. Main findings include quantification of near-coastal monitoring gaps and long-term nutrient and pollutant memory in the subsurface (soil-groundwater-sediment) water systems of drainage basins. The former may significantly mask nutrient and pollutant loads to the sea while the latter may continue to uphold large loads to inland and coastal waters long time after source mitigation. A methodology is presented for finding a rational trade-off between the two resource-demanding options to reduce, or accept and explicitly account for the uncertainties implied by these monitoring gaps and long-term nutrient-pollution memories and time lags, and other knowledge, data and model uncertainties that limit the effectiveness and efficiency of water pollution and eutrophication management.

Nutrient loading and selected water-quality and biological characteristics of Dickinson Bayou near Houston, Texas, 1995-97

USGS Publications Warehouse

East, Jeffery W.; Paul, Edna M.; Porter, Stephen D.

1998-01-01

Algal samples were collected at seven stations and were analyzed for periphyton identification and enumeration, and chlorophyll a and chlorophyll b concentrations. The large relative abundance of soil algae at stations in the middle of the watershed likely indicates the cumulative effects on water quality of agricultural nonpoint sources. Farther downstream near the State Highway 3 bridge, and downstream of three major tributary inflows, the increase in abundance of soil algae to a larger-than-expected level might reflect water-quality influences from predominantly urban nonpoint sources in the drainage basins of the three major tributary inflows. Nutrient concentrations do not appear to limit algal production in the upper (non-tidal) reach of Dickinson Bayou; but nutrient concentrations could have been limiting benthicalgal production in the lower (tidal) reach of the bayou during the time of the synoptic survey. If nitrogen is the limiting resource for algal productivity in the tidal reach of Dickinson Bayou, eutrophication of the system could be (at least partially) mitigated if nonpoint-source nutrient loads into the Bayou were reduced. 

External nutrient loading from land, sea and atmosphere to all 656 Swedish coastal water bodies.

PubMed

Bryhn, Andreas C; Dimberg, Peter H; Bergström, Lena; Fredriksson, Ronny E; Mattila, Johanna; Bergström, Ulf

2017-01-30

Identifying the main sources of nutrient loading is a key factor for efficient mitigation of eutrophication. This study has investigated the pathways of external nutrient loading to 656 coastal water bodies along the entire Swedish coastline. The studied water bodies have been delineated to meet requirements in the European Union's Water Framework Directive, and recent status assessments have shown that 57% of them fail to attain good or high ecological status with respect to nutrients. The analysis in the study was performed on data from mass-balance based nutrient budgets computed using the modelling framework Vattenwebb. The external nutrient contribution from the sea to the water bodies was highly variable, ranging from about 1% to nearly 100%, but the median contribution was >99% of the total external loading regarding both nitrogen and phosphorus. External loading from the atmosphere and local catchment area played a minor role in general. However, 45 coastal water bodies received >25% of the external nitrogen and phosphorus from their catchments. Loading from land typically peaked in April following ice-break and snow melting and was comparatively low during summer. The results indicate that for many eutrophicated Swedish coastal water bodies, nutrient abatement is likely to be optimally effective when potential measures in all of the catchment area of the concerned sea basin are considered. Local-scale mitigation in single water bodies will likely be locally effective only in the small proportion of areas where water and thereby also nutrient input from the catchment is high compared to the influx from the sea. Future studies should include nutrient reduction scenarios in order to refine these conclusions and to identify relevant spatial scales for coastal eutrophication mitigation measures from a water body perspective. Copyright © 2017 Elsevier Ltd. All rights reserved.

Water Quality Protection from Nutrient Pollution: Case Analysis

EPA Science Inventory

Water bodies and coastal areas around the world are threatened by increases in upstream sediment and nutrient loads, which influence drinking water sources, aquatic species, and other ecologic functions and services of streams, lakes, and coastal water bodies. For example, incre...

NONPOINT SOURCES AND WATER QUALITY TRADING

EPA Science Inventory

Management of nonpoint sources (NPS) of nutrients may reduce discharge levels more cost effectively than can additional controls on point sources (PS); water quality trading (WQT), where a PS buys nutrient or sediment reductions from an NPS, may be an alternative means for the PS...

Assessment of nutrient loadings of a large multipurpose prairie reservoir

NASA Astrophysics Data System (ADS)

Morales-Marín, L. A.; Wheater, H. S.; Lindenschmidt, K. E.

2017-07-01

The relatively low water flow velocities in reservoirs cause them to have high capacities for retaining sediments and pollutants, which can lead to a reduction in downstream nutrient loading. Hence, nutrients can progressively accumulate in reservoirs, resulting in the deterioration of aquatic ecosystems and water quality. Lake Diefenbaker (LD) is a large multipurpose reservoir, located on the South Saskatchewan River (SSR), that serves as a major source of freshwater in Saskatchewan, Canada. Over the past several years, changes in land use (e.g. expansion of urban areas and industrial developments) in the reservoir's catchment have heightened concerns about future water quality in the catchment and in the reservoir. Intensification of agricultural activities has led to an increase in augmented the application of manure and fertilizer for crops and pasture. Although previous research has attempted to quantify nutrient retention in LD, there is a knowledge gap related to the identification of major nutrient sources and quantification of nutrient export from the catchment at different spatial scales. Using the SPAtially Referenced Regression On Watershed (SPARROW) model, this gap has been addressed by assessing water quality regionally, and identifying spatial patterns of factors and processes that affect water quality in the LD catchment. Model results indicate that LD retains about 70% of the inflowing total nitrogen (TN) and 90% of the inflowing total phosphorus (TP) loads, of which fertilizer and manure applied to agricultural fields contribute the greatest proportion. The SPARROW model will be useful as a tool to guide the optimal implementation of nutrient management plans to reduce nutrient inputs to LD.

Relation of watershed setting and stream nutrient yields at selected sites in central and eastern North Carolina, 1997-2008

USGS Publications Warehouse

Harden, Stephen L.; Cuffney, Thomas F.; Terziotti, Silvia; Kolb, Katharine R.

2013-01-01

Data collected between 1997 and 2008 at 48 stream sites were used to characterize relations between watershed settings and stream nutrient yields throughout central and eastern North Carolina. The focus of the investigation was to identify environmental variables in watersheds that influence nutrient export for supporting the development and prioritization of management strategies for restoring nutrient-impaired streams. Nutrient concentration data and streamflow data compiled for the 1997 to 2008 study period were used to compute stream yields of nitrate, total nitrogen (N), and total phosphorus (P) for each study site. Compiled environmental data (including variables for land cover, hydrologic soil groups, base-flow index, streams, wastewater treatment facilities, and concentrated animal feeding operations) were used to characterize the watershed settings for the study sites. Data for the environmental variables were analyzed in combination with the stream nutrient yields to explore relations based on watershed characteristics and to evaluate whether particular variables were useful indicators of watersheds having relatively higher or lower potential for exporting nutrients. Data evaluations included an examination of median annual nutrient yields based on a watershed land-use classification scheme developed as part of the study. An initial examination of the data indicated that the highest median annual nutrient yields occurred at both agricultural and urban sites, especially for urban sites having large percentages of point-source flow contributions to the streams. The results of statistical testing identified significant differences in annual nutrient yields when sites were analyzed on the basis of watershed land-use category. When statistical differences in median annual yields were noted, the results for nitrate, total N, and total P were similar in that highly urbanized watersheds (greater than 30 percent developed land use) and (or) watersheds with greater than 10 percent point-source flow contributions to streamflow had higher yields relative to undeveloped watersheds (having less than 10 and 15 percent developed and agricultural land uses, respectively) and watersheds with relatively low agricultural land use (between 15 and 30 percent). The statistical tests further indicated that the median annual yields for total P were statistically higher for watersheds with high agricultural land use (greater than 30 percent) compared to the undeveloped watersheds and watersheds with low agricultural land use. The total P yields also were higher for watersheds with low urban land use (between 10 and 30 percent developed land) compared to the undeveloped watersheds. The study data indicate that grouping and examining stream nutrient yields based on the land-use classifications used in this report can be useful for characterizing relations between watershed settings and nutrient yields in streams located throughout central and eastern North Carolina. Compiled study data also were analyzed with four regression tree models as a means of determining which watershed environmental variables or combination of variables result in basins that are likely to have high or low nutrient yields. The regression tree analyses indicated that some of the environmental variables examined in this study were useful for predicting yields of nitrate, total N, and total P. When the median annual nutrient yields for all 48 sites were evaluated as a group (Model 1), annual point-source flow yields had the greatest influence on nitrate and total N yields observed in streams, and annual streamflow yields had the greatest influence on yields of total P. The Model 1 results indicated that watersheds with higher annual point-source flow yields had higher annual yields of nitrate and total N, and watersheds with higher annual streamflow yields had higher annual yields of total P. When sites with high point-source flows (greater than 10 percent of total streamflow) were excluded from the regression tree analyses (Models 2–4), the percentage of forested land in the watersheds was identified as the primary environmental variable influencing stream yields for both total N and total P. Models 2, 3 and 4 did not identify any watershed environmental variables that could adequately explain the observed variability in the nitrate yields among the set of sites examined by each of these models. The results for Models 2, 3, and 4 indicated that watersheds with higher percentages of forested land had lower annual total N and total P yields compared to watersheds with lower percentages of forested land, which had higher median annual total N and total P yields. Additional environmental variables determined to further influence the stream nutrient yields included median annual percentage of point-source flow contributions to the streams, variables of land cover (percentage of forested land, agricultural land, and (or) forested land plus wetlands) in the watershed and (or) in the stream buffer, and drainage area. The regression tree models can serve as a tool for relating differences in select watershed attributes to differences in stream yields of nitrate, total N, and total P, which can provide beneficial information for improving nutrient management in streams throughout North Carolina and for reducing nutrient loads to coastal waters.

Magnitudes, nature, and effects of point and nonpoint discharges in the Chattahoochee River basin, Atlanta to West Point Dam, Georgia

USGS Publications Warehouse

Stamer, J.K.; Cherry, R.N.; Faye, R.E.; Kleckner, R.L.

1978-01-01

On an average annual basis and during the storm period of March 12-15, 1976, nonpoint-source loads for most constituents were larger than point-source loads at the Whitesburg station, located on the Chattahoochee River about 40 miles downstream from Atlanta, GA. Most of the nonpoint-source constituent loads in the Atlanta to Whitesburg reach were from urban areas. Average annual point-source discharges accounted for about 50 percent of the dissolved nitrogen, total nitrogen, and total phosphorus loads and about 70 percent of the dissolved phosphorus loads at Whitesburg. During a low-flow period, June 1-2, 1977, five municipal point-sources contributed 63 percent of the ultimate biochemical oxygen demand, and 97 percent of the ammonium nitrogen loads at the Franklin station, at the upstream end of West Point Lake. Dissolved-oxygen concentrations of 4.1 to 5.0 milligrams per liter occurred in a 22-mile reach of the river downstream from Atlanta due about equally to nitrogenous and carbonaceous oxygen demands. The heat load from two thermoelectric powerplants caused a decrease in dissolved-oxygen concentration of about 0.2 milligrams per liter. Phytoplankton concentrations in West Point Lake, about 70 miles downstream from Atlanta, could exceed three million cells per millimeter during extended low-flow periods in the summer with present point-source phosphorus loads. (Woodard-USGS)

Forms and subannual variability of nitrogen and phosphorus loading to global river networks over the 20th century

NASA Astrophysics Data System (ADS)

Vilmin, Lauriane; Mogollón, José M.; Beusen, Arthur H. W.; Bouwman, Alexander F.

2018-04-01

Nitrogen (N) and phosphorus (P) play a major role in the biogeochemical functioning of aquatic systems. N and P transfer to surface freshwaters has amplified during the 20th century, which has led to widespread eutrophication problems. The contribution of different sources, natural and anthropogenic, to total N and P loading to river networks has recently been estimated yearly using the Integrated Model to Assess the Global Environment - Global Nutrient Model (IMAGE-GNM). However, eutrophic events generally result from a combination of physicochemical conditions governed by hydrological dynamics and the availability of specific nutrient forms that vary at subyearly timescales. In the present study, we define for each simulated nutrient source: i) its speciation, and ii) its subannual temporal pattern. Thereby, we simulate the monthly loads of different N (ammonium, nitrate + nitrite, and organic N) and P forms (dissolved and particulate inorganic P, and organic P) to global river networks over the whole 20th century at a half-degree spatial resolution. Results indicate that, together with an increase in the delivery of all nutrient forms to global rivers, the proportion of inorganic forms in total N and P inputs has risen from 30 to 43% and from 56 to 65%, respectively. The high loads originating from fertilized agricultural lands and the increasing proportion of sewage inputs have led to a greater proportion of DIN forms (ammonium and nitrate), that are usually more bioavailable. Soil loss from agricultural lands, which delivers large amounts of particle-bound inorganic P to surface freshwaters, has become the dominant P source, which is likely to lead to an increased accumulation of legacy P in slow flowing areas (e.g., lakes and reservoirs). While the TN:TP ratio of the loads has remained quite stable, the DIN:DIP molar ratio, which is likely to affect algal development the most, has increased from 18 to 27 globally. Human activities have also affected the timing of nutrient delivery to surface freshwaters. Increasing wastewater emissions in growing urban areas induces constant local pressure on the quality of aquatic systems by delivering generally highly bioavailable nutrient forms, even in periods of low runoff.

Impact of Submarine Groundwater Discharge on Marine Water Quality and Reef Biota of Maui

PubMed Central

Bishop, James M.

2016-01-01

Generally unseen and infrequently measured, submarine groundwater discharge (SGD) can transport potentially large loads of nutrients and other land-based contaminants to coastal ecosystems. To examine this linkage we employed algal bioassays, benthic community analysis, and geochemical methods to examine water quality and community parameters of nearshore reefs adjacent to a variety of potential, land-based nutrient sources on Maui. Three common reef algae, Acanthophora spicifera, Hypnea musciformis, and Ulva spp. were collected and/or deployed at six locations with SGD. Algal tissue nitrogen (N) parameters (δ15N, N %, and C:N) were compared with nutrient and δ15N-nitrate values of coastal groundwater and nearshore surface water at all locations. Benthic community composition was estimated for ten 10-m transects per location. Reefs adjacent to sugarcane farms had the greatest abundance of macroalgae, low species diversity, and the highest concentrations of N in algal tissues, coastal groundwater, and marine surface waters compared to locations with low anthropogenic impact. Based on δ15N values of algal tissues, we estimate ca. 0.31 km2 of Kahului Bay is impacted by effluent injected underground at the Kahului Wastewater Reclamation Facility (WRF); this region is barren of corals and almost entirely dominated by colonial zoanthids. Significant correlations among parameters of algal tissue N with adjacent surface and coastal groundwater N indicate that these bioassays provided a useful measure of nutrient source and loading. A conceptual model that uses Ulva spp. tissue δ15N and N % to identify potential N source(s) and relative N loading is proposed for Hawaiʻi. These results indicate that SGD can be a significant transport pathway for land-based nutrients with important biogeochemical and ecological implications in tropical, oceanic islands. PMID:27812171

Impact of Submarine Groundwater Discharge on Marine Water Quality and Reef Biota of Maui.

PubMed

Amato, Daniel W; Bishop, James M; Glenn, Craig R; Dulai, Henrietta; Smith, Celia M

2016-01-01

Generally unseen and infrequently measured, submarine groundwater discharge (SGD) can transport potentially large loads of nutrients and other land-based contaminants to coastal ecosystems. To examine this linkage we employed algal bioassays, benthic community analysis, and geochemical methods to examine water quality and community parameters of nearshore reefs adjacent to a variety of potential, land-based nutrient sources on Maui. Three common reef algae, Acanthophora spicifera, Hypnea musciformis, and Ulva spp. were collected and/or deployed at six locations with SGD. Algal tissue nitrogen (N) parameters (δ15N, N %, and C:N) were compared with nutrient and δ15N-nitrate values of coastal groundwater and nearshore surface water at all locations. Benthic community composition was estimated for ten 10-m transects per location. Reefs adjacent to sugarcane farms had the greatest abundance of macroalgae, low species diversity, and the highest concentrations of N in algal tissues, coastal groundwater, and marine surface waters compared to locations with low anthropogenic impact. Based on δ15N values of algal tissues, we estimate ca. 0.31 km2 of Kahului Bay is impacted by effluent injected underground at the Kahului Wastewater Reclamation Facility (WRF); this region is barren of corals and almost entirely dominated by colonial zoanthids. Significant correlations among parameters of algal tissue N with adjacent surface and coastal groundwater N indicate that these bioassays provided a useful measure of nutrient source and loading. A conceptual model that uses Ulva spp. tissue δ15N and N % to identify potential N source(s) and relative N loading is proposed for Hawai'i. These results indicate that SGD can be a significant transport pathway for land-based nutrients with important biogeochemical and ecological implications in tropical, oceanic islands.

Bayesian Modeling of the Assimilative Capacity Component of Stream Nutrient Export

EPA Science Inventory

Implementing stream restoration techniques and best management practices to reduce nonpoint source nutrients implies enhancement of the assimilative capacity for the stream system. In this paper, a Bayesian method for evaluating this component of a TMDL load capacity is developed...

Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States1

PubMed Central

Rebich, Richard A; Houston, Natalie A; Mize, Scott V; Pearson, Daniel K; Ging, Patricia B; Evan Hornig, C

2011-01-01

Abstract SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). PMID:22457582

Effect of phosphorous concentrations on sedimentary distributions and isotopic composition of algal lipid biomarkers in lakes from central Switzerland

NASA Astrophysics Data System (ADS)

Ladd, N.; Dubois, N.; Schubert, C. J.

2015-12-01

Lakes in the Swiss central plateau experienced increasing anthropogenic phosphorous loading throughout much of the 20th century. Since the 1980s concerted remediation efforts on the part of the Swiss government have significantly reduced P concentrations in most lakes and reversed previous eutrophication. However, P concentrations remain elevated above their preindustrial levels in many sites. High quality monitoring of lake nutrient levels since the 1950s, along with several lakes of wide-ranging P concentrations in close proximity, make central Switzerland an ideal location for studying the ways in which nutrient loading affects the organic composition of lacustrine sediments. Results of such studies can be used to develop proxies of eutrophication in sites where fewer historical data exist, and to reconstruct historical P concentrations in local lakes from the time before record keeping began. We analyzed the distributions of algal lipid biomarkers from surface sediment and sediment traps collected in the spring of 2015 from ten lakes with variable P concentrations in central Switzerland. Sedimentary lipid distributions from these lakes confirm that biomarkers associated with algal and cyanobacterial sources are more abundant in the sediment of lakes with greater P loading. The dry sedimentary concentrations of biomarkers such as brassicasterol (primarily diatom source) and diplopterol (cyanobacteria source), as well as the less source specific short-chain n-alkanols, linearly increase from 0.3 - 1.9 μg/g as total phosphorous in the upper water column increases by 1 μg/L over a range of 7 - 50 μg/L. We also present preliminary hydrogen isotope data from these biomarkers. Hydrogen isotopes of algal lipids primarily reflect the source water in which the algae grew, and this relationship has been developed as a paleohydrologic proxy. However, laboratory cultures of marine algae demonstrate that they discriminate more against 2H under nutrient replete conditions. We present the first field assessment of how nutrient availability influences 2H fractionation in freshwater algae, and demonstrate how such measurements can be used to infer past information about anthropogenic nutrient loading.

Chemical fractionation of lake sediments to determine the effects of land-use change on nutrient loading

NASA Astrophysics Data System (ADS)

Heathwaite, A. L.

1994-07-01

Lake studies allow contemporary sediment and nutrient dynamics to be placed in a historical context in order that trends and rates of change in catchment inputs may be calculated. Here, a synthesis of the temporal information contained in catchment and lake sediment records is attempted. A chemical fractionation technique is used to isolate the different sediment sources contained in the lake core, and 210Pb dates provide an accurate record of changes in lake sediment sources over the past 100 years. The extent to which land-use records, collated from agricultural census returns, and process-based studies of sediment and nutrient export from different catchment land uses can be used to explain the trends observed in the lake sediments is examined. Sediment influx to the study lake has increased from less than 2 mm year -1 prior to the Second World War to over 10 mm year -1 at present. The source of the sediment is largely unaltered and unweathered allochthonous material eroded from the catchment. Land-use records suggest that the intensification of agriculture, characterized by a shift towards arable land immediately postwar, followed by an increase in the area of temporary grass in the 1960s, may be the cause of accelerated catchment erosion; both land-use changes would have increased the area of ploughed land in the catchment. An increase in the number of cattle and sheep in the catchment from around 2000 and 6000, respectively, in the 1940s, to a peak of nearly 7000 cattle and over 15 000 sheep in the 1980s, provides a further source of sediment and nutrients. Livestock are grazed on permanent grassland which is commonly located on steep hillslopes and in riparian zones where saturation-excess surface runoff may be an important hydrological pathway. Rainfall simulation experiments show that surface runoff from heavily grazed grassland has a high suspended sediment, ammonium-nitrogen and particulate phosphorus load. The combined effect of the long-term increase in the organic loading from livestock and the inorganic N and P load from fertilizers, may be the source of nutrient enrichment in the lake.

Watershed modeling tools and data for prognostic and diagnostic

NASA Astrophysics Data System (ADS)

Chambel-Leitao, P.; Brito, D.; Neves, R.

2009-04-01

When eutrophication is considered an important process to control it can be accomplished reducing nitrogen and phosphorus losses from both point and nonpoint sources and helping to assess the effectiveness of the pollution reduction strategy. HARP-NUT guidelines (Guidelines on Harmonized Quantification and Reporting Procedures for Nutrients) (Borgvang & Selvik, 2000) are presented by OSPAR as the best common quantification and reporting procedures for calculating the reduction of nutrient inputs. In 2000, OSPAR HARP-NUT guidelines on a trial basis. They were intended to serve as a tool for OSPAR Contracting Parties to report, in a harmonized manner, their different commitments, present or future, with regard to nutrients under the OSPAR Convention, in particular the "Strategy to Combat Eutrophication". HARP-NUT Guidelines (Borgvang and Selvik, 2000; Schoumans, 2003) were developed to quantify and report on the individual sources of nitrogen and phosphorus discharges/losses to surface waters (Source Orientated Approach). These results can be compared to nitrogen and phosphorus figures with the total riverine loads measured at downstream monitoring points (Load Orientated Approach), as load reconciliation. Nitrogen and phosphorus retention in river systems represents the connecting link between the "Source Orientated Approach" and the "Load Orientated Approach". Both approaches are necessary for verification purposes and both may be needed for providing the information required for the various commitments. Guidelines 2,3,4,5 are mainly concerned with the sources estimation. They present a set of simple calculations that allow the estimation of the origin of loads. Guideline 6 is a particular case where the application of a model is advised, in order to estimate the sources of nutrients from diffuse sources associated with land use/land cover. The model chosen for this was SWAT (Arnold & Fohrer, 2005) model because it is suggested in the guideline 6 and because it's widely used in the world. Watershed models can be characterized by the high number of processes associated simulated. The estimation of these processes is also data intensive, requiring data on topography, land use / land cover, agriculture practices, soil type, precipitation, temperature, relative humidity, wind and radiation. Every year new data is being made available namely by satellite, that has allow to improve the quality of model input and also the calibration of the models (Galvão et. al, 2004b). Tools to cope with the vast amount of data have been developed: data formatting, data retrieving, data bases, metadata bases. The high number of processes simulated in watershed models makes them very wide in terms of output. The SWAT model outputs were modified to produce MOHID compliant result files (time series and HDF). These changes maintained the integrity of the original model, thus guarantying that results remain equal to the original version of SWAT. This allowed to output results in MOHID format, thus making it possible to immediately process it with MOHID visualization and data analysis tools (Chambel-Leitão et. al 2007; Trancoso et. al, 2009). Besides SWAT was modified to produce results files in HDF5 format, this allows the visualization of watershed properties (modeled by SWAT) in animated maps using MOHID GIS. The modified version of SWAT described here has been applied to various national and European projects. Results of the application of this modified version of SWAT to estimate hydrology and nutrients loads to estuaries and water bodies will be shown (Chambel-Leitão, 2008; Yarrow & Chambel-Leitão 2008; Chambel-Leitão et. al 2008; Yarrow & P. Chambel-Leitão, 2007; Yarrow & P. Chambel-Leitão, 2007; Coelho et. al., 2008). Keywords: Watershed models, SWAT, MOHID LAND, Hydrology, Nutrient Loads Arnold, J. G. and Fohrer, N. (2005). SWAT2000: current capabilities and research opportunities in applied watershed modeling. Hydrol. Process. 19, 563-572 Borgvang, S-A. & Selvik, J.S., 2000, eds. Development of HARP Guidelines - Harmonised Quantification and Reporting Procedure for Nutrients. SFT Report 1759/2000. ISBN 82-7655-401-6. 179 pp. Chambel-Leitão P. (2008) Load and flow estimation: HARP-NUT guidelines and SWAT model description. In Perspectives on Integrated Coastal Zone Management in South America R Neves, J Baretta & M Mateus (eds.). IST Press, Lisbon, Portugal. (ISBN: 978-972-8469-74-0) Chambel-Leitão P. Sampaio. A., Almeida, P. (2008) Load and flow estimation in Santos watersheds. In Perspectives on Integrated Coastal Zone Management in South America R Neves, J Baretta & M Mateus (eds.). IST Press, Lisbon, Portugal. (ISBN: 978-972-8469-74-0) Chambel-Leitão P., F. Braunschweig, L. Fernandes, R. Neves, P. Galvão. (2007) Integration of MOHID model and tools with SWAT model, submitted to the Proceedings of the, 4th International SWAT Conference, July 2-6 2007. Coelho H., Silva A., P. Chambel-Leitão, Obermann M. (2008) On The Origin Of Cyanobacteria Blooms In The Enxoé Reservoir. 13th World Water Congress, Montpellier, France Galvão P., Chambel-Leitão, P., P. Leitão, R. Neves. (2004a) A different approach to the modified Picard method for water flow in variably saturated media. Computational Methods in Water Resources. Chapel Hill, North Carolina USA Galvão P., Neves R., Silva A., Chambel-Leitão P. & F. Braunchweig (2004b) Integrated Watershed Modeling. Proceedings of MERIS User Workshop ESA-ESRIN, Frascati, Italy May 2004. Neves R., Galvao P., Braunschewig F.Chambel-Leitão P. (2007) New Approaches to Integrated Watershed Modeling. Proceedings of SPS (NFA) 5th Workshop on Sustainable Use And Development Of Watersheds For Human Security And Peace October 22-26, 2007 Istanbul, TURKEY Schoumans, O.F. & Silgram, M. (eds.), 2003. Review and literature evaluation of Quantification Tools for the assessment of nutrient losses at catchment scale. EUROHARP report 1-2003, NIVA report SNO 4739-2003, ISBN 82-557-4411-5 Trancoso, R., F. Braunschweig, Chambel-Leitão P., Neves, R., Obermann, M. (2009) An advanced modelling tool for simulating complex river systems. Accepted for publication in Journal of Total Environment. Yarrow M., Chambel-Leitão P. (2006) Calibration of the SWAT model to the Aysén basin of the Chilean Patagonia: Challenges and Lessons. Proceedings of the Watershed Management to Meet Water Quality Standards and TMDLS (Total Maximum Daily Load) 10-14 March 2007, San Antonio, Texas 701P0207. Yarrow M., Chambel-Leitão P.. (2007) Simulating Nothfagus forests in the Chilean Patagonia: a test and analysis of tree growth and nutrient cycling in swat. Submited to the Proceedings of the , 4th International SWAT Conference July 2-6 2007. Yarrow, M., Chambel-Leitão P. (2008) Estimation of loads in the Aysén Basin of the Chilean Patagonia: SWAT model and Harp-Nut guidelines. In Perspectives on Integrated Coastal Zone Management in South America R Neves, J Baretta & M Mateus (eds.). IST Press, Lisbon, Portugal. (ISBN: 978-972-8469-74-0)

Nutrient Losses from Non-Point Sources or from Unidentified Point Sources? Application Examples of the Smartphone Based Nitrate App.

NASA Astrophysics Data System (ADS)

Rozemeijer, J.; Ekkelenkamp, R.; van der Zaan, B.

2017-12-01

In 2016 Deltares launched the free to use Nitrate App which accurately reads and interprets nitrate test strips. The app directly displays the measured concentration and gives the option to share the result. Shared results are visualised in map functionality within the app and online. Since its introduction we've been seeing an increasing number of nitrate app applications. In this presentation we show some unanticipated types of application. The Nitrate App was originally intended to enable farmers to measure nitrate concentrations on their own farms. This may encourage farmers to talk to specialists about the right nutrient best management practices (BMP's) for their farm. Several groups of farmers have recently started to apply the Nitrate App and to discuss their results with each other and with the authorities. Nitrate concentration routings in catchments have proven to be another useful application. Within a day a person can generate a catchment scale nitrate concentration map identifying nitrate loss hotspots. In several routings in agricultural catchments clear point sources were found, for example at small scale manure processing plants. These routings proved that the Nitrate App can help water managers to target conservation practices more accurately to areas with the highest nitrate concentrations and loads. Other current applications are the screening of domestic water wells in California, the collection of extra measurements (also pH and NH4) in the National Monitoring Network for the Evaluation of the Manure Policy in the Netherlands, and several educational initiatives in cooperation with schools and universities.

Development of an epiphyte indicator of nutrient enrichment. A ...

EPA Pesticide Factsheets

An extensive review of the literature on epiphytes on submerged aquatic vegetation (SAV), primarily seagrasses but including some brackish and freshwater rooted macrophytes, was conducted in order to evaluate the evidence for response of epiphyte metrics to increased nutrients. Evidence from field observational studies together with laboratory and field mesocosm experiments was assembled from the literature and evaluated for evidence of a hypothesized positive response to nutrient addition. There was general consistency in the results to confirm that elevated nutrients tended to increase the load of epiphytes on the surface of SAV, in the absence of other limiting factors. In spite of multiple sources of uncontrolled variation, positive relationships of epiphyte load to nutrient concentration or load (either N or P) were often observed along strong anthropogenic or natural nutrient gradients in coastal regions, although response patterns may only be evident for parts of the year. Mesocosm nutrient studies tended to be more common for temperate regions and field addition studies more common for tropical and subtropical regions. Addition of nutrients via the water column tended to elicit stronger epiphyte responses than sediment additions, and may be a factor in the lack of epiphyte response reported in some studies. Mesograzer activity is a critical covariate for epiphyte response under experimental nutrient elevation, but the epiphyte response is highly de

Integrated watershed planning across jurisdictional boundaries

NASA Astrophysics Data System (ADS)

Watts, A. W.; Roseen, R.; Stacey, P.; Bourdeau, R.

2014-12-01

We will present the foundation for an Coastal Watershed Integrated Plan for three communities in southern New Hampshire. Small communities are often challenged by complex regulatory requirements and limited resources, but are wary of perceived risks in engaging in collaborative projects with other communities. Potential concerns include loss of control, lack of resources to engage in collaboration, technical complexity, and unclear benefits. This project explores a multi-town subwatershed application of integrated planning across jurisdictional boundaries that addresses some of today's highest priority water quality issues: wastewater treatment plant upgrades for nutrient removal; green infrastructure stormwater management for developing and re-developing areas; and regional monitoring of ecosystem indicators in support of adaptive management to achieve nutrient reduction and other water quality goals in local and downstream waters. The project outcome is a collaboratively-developed inter-municipal integrated plan, and a monitoring framework to support cross jurisdictional planning and assess attainment of water quality management goals. This research project has several primary components: 1) assessment of initial conditions, including both the pollutant load inputs and the political, economic and regulatory status within each community, 2) a pollutant load model for point and non-point sources, 3) multi-criteria evaluation of load reduction alternatives 4) a watershed management plan optimized for each community, and for Subwatersheds combining multiple communities. The final plan will quantify the financial and other benefits/drawbacks to each community for both inter municipal and individual pollution control approaches. We will discuss both the technical and collaborative aspects of the work, with lessons learned regarding science to action, incorporation of social, economic and water quality assessment parameters, and stakeholder/researcher interaction.

[Estimation of nonpoint source pollutant loads and optimization of the best management practices (BMPs) in the Zhangweinan River basin].

PubMed

Xu, Hua-Shan; Xu, Zong-Xue; Liu, Pin

2013-03-01

One of the key techniques in establishing and implementing TMDL (total maximum daily load) is to utilize hydrological model to quantify non-point source pollutant loads, establish BMPs scenarios, reduce non-point source pollutant loads. Non-point source pollutant loads under different years (wet, normal and dry year) were estimated by using SWAT model in the Zhangweinan River basin, spatial distribution characteristics of non-point source pollutant loads were analyzed on the basis of the simulation result. During wet years, total nitrogen (TN) and total phosphorus (TP) accounted for 0.07% and 27.24% of the total non-point source pollutant loads, respectively. Spatially, agricultural and residential land with steep slope are the regions that contribute more non-point source pollutant loads in the basin. Compared to non-point source pollutant loads with those during the baseline period, 47 BMPs scenarios were set to simulate the reduction efficiency of different BMPs scenarios for 5 kinds of pollutants (organic nitrogen, organic phosphorus, nitrate nitrogen, dissolved phosphorus and mineral phosphorus) in 8 prior controlled subbasins. Constructing vegetation type ditch was optimized as the best measure to reduce TN and TP by comparing cost-effective relationship among different BMPs scenarios, and the costs of unit pollutant reduction are 16.11-151.28 yuan x kg(-1) for TN, and 100-862.77 yuan x kg(-1) for TP, which is the most cost-effective measure among the 47 BMPs scenarios. The results could provide a scientific basis and technical support for environmental protection and sustainable utilization of water resources in the Zhangweinan River basin.

Nutrient attenuation in rivers and streams, Puget Sound Basin, Washington

USGS Publications Warehouse

Sheibley, Rich W.; Konrad, Christopher P.; Black, Robert W.

2015-01-01

From a management perspective, preservation and improvement of instream nutrient attenuation should focus on increasing the travel time through a reach and contact time of water sediment (reactive) surfaces and lowering nutrient concentrations (and loads) to avoid saturation of instream attenuation and increase attenuation efficiency. These goals can be reached by maintaining and restoring channel-flood plain connectivity, maintaining and restoring healthy riparian zones along streams, managing point and nonpoint nutrient loads to streams and rivers, and restoring channel features that promote attenuation such as the addition of woody debris and maintaining pool-riffle morphologies. Many of these management approaches are already being undertaken during projects aimed to restore quality salmon habitat. Therefore, there is a dual benefit to these projects that also may lead to enhanced potential for nitrogen and phosphorus attenuation.

Application of the ReNuMa model in the Sha He river watershed: tools for watershed environmental management.

PubMed

Sha, Jian; Liu, Min; Wang, Dong; Swaney, Dennis P; Wang, Yuqiu

2013-07-30

Models and related analytical methods are critical tools for use in modern watershed management. A modeling approach for quantifying the source apportionment of dissolved nitrogen (DN) and associated tools for examining the sensitivity and uncertainty of the model estimates were assessed for the Sha He River (SHR) watershed in China. The Regional Nutrient Management model (ReNuMa) was used to infer the primary sources of DN in the SHR watershed. This model is based on the Generalized Watershed Loading Functions (GWLF) and the Net Anthropogenic Nutrient Input (NANI) framework, modified to improve the characterization of subsurface hydrology and septic system loads. Hydrochemical processes of the SHR watershed, including streamflow, DN load fluxes, and corresponding DN concentration responses, were simulated following calibrations against observations of streamflow and DN fluxes. Uncertainty analyses were conducted with a Monte Carlo analysis to vary model parameters for assessing the associated variations in model outputs. The model performed accurately at the watershed scale and provided estimates of monthly streamflows and nutrient loads as well as DN source apportionments. The simulations identified the dominant contribution of agricultural land use and significant monthly variations. These results provide valuable support for science-based watershed management decisions and indicate the utility of ReNuMa for such applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sources and transport of sediment, nutrients, and oxygen-demanding substances in the Minnesota River basin, 1989-92

USGS Publications Warehouse

Payne, G.A.

1994-01-01

The Minnesota River, 10 major tributaries, and 21 springs were sampled to determine the sources and transport of sediment, nutrients, and oxygen- demanding substances. The study was part of a four-year assessment of non-point source pollution in the Minnesota River Basin. Runoff from tributary watersheds was identified as the primary source of suspended sediment and nutrients in the Minnesota River mainstem. Suspended-sediment, phosphorus, and nitrate concentrations were elevated in all major tributaries during runoff, but tributaries in the south-central and eastern part of the basin produce the highest annual loading to the mainstem because of higher annual precipitation and runoff in that part of the basin. Particle-size analyses showed that most of the suspended sediment in transport consisted of silt- and clay-size material. Phosphorus enrichment was indicated throughout the mainstem by total phosphorus concentrations that ranged from 0.04 to 0.48 mg/L with a median value of 0.22 mg/L, and an interquartile range of 0.15 to 0.29 mg/L. Nitrate concentrations periodically exceeded drinking water standards in tributaries draining the south-central and eastern part of the basin. Oxygen demand was most elevated during periods of summer low flow. Correlations between levels of biochemical oxygen demand and levels of algal productivity suggest that algal biomass comprises much of the oxygen-demanding material in the mainstem. Transport of sediment, nutrients, and organic carbon within the mainstem was found to be conservative, with nearly all tributary inputs being transported downstream. Uptake and utilization of nitrate and orthophosphorus was indicated during low flow, but at normal and high flow, inputs of these constituents greatly exceeded biological utilization.

Couplings of watersheds and coastal waters: Sources and consequences of nutrient enrichment in Waquoit Bay, Massachusetts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valiela, I.; Foreman, K.; LaMontagne, M.

1992-12-01

Human activities on coastal watersheds provide the major sources of nutrients entering shallow coastal ecosystems. Nutrient loadings from watersheds alter structure and function of receiving aquatic ecosystems. To investigate this coupling of land to marine systems, a series of subwatersheds of Waquoit Bay differing in degree of urbanization and with widely different nutrient loading rates was studied. The subwatersheds differ in septic tanks numbers and forest acreage. Ground water is the major mechanism that transports nutrients to coastal waters. Some attenuation of nutrient concentrations within the aquifer or at the sediment-water interface, but significant increases in the nutrient content ofmore » groundwater arriving at the shore's edge are in urbanized areas. The groundwater flows through the sediment-water boundary, and sufficient groundwater-borne nutrients (nitrogen in particular) traverse the sediment-water boundary to cause significant changes in the aquatic ecosystem. These loading-dependent alterations include increased nutrients in water, greater primary production by phytoplankton, and increased macroalgal biomass and growth. The increased macroalgal biomass dominates the bay ecosystem through second- or third-order effects such as alterations of nutrient status of water columns and increasing frequency of anoxic events. The increases in seaweeds have decreased the areas covered by eelgrass habitats. The change in habitat type, plus the increased frequency of anoxic events, change the composition of the benthic fauna. The importance of bottom-up control in shallow coastal food webs is evident. The coupling of land to sea by groundwater-borne nutrient transport is mediated by a complex series of steps, making it unlikely to find a one-to-one relation between land use and conditions in the aquatic ecosystem. Appropriate models may provide a way to deal with the complexities of the coupling. 22 refs., 14 figs., 5 tabs.« less

A Bayesian methodological framework for accommodating interannual variability of nutrient loading with the SPARROW model

NASA Astrophysics Data System (ADS)

Wellen, Christopher; Arhonditsis, George B.; Labencki, Tanya; Boyd, Duncan

2012-10-01

Regression-type, hybrid empirical/process-based models (e.g., SPARROW, PolFlow) have assumed a prominent role in efforts to estimate the sources and transport of nutrient pollution at river basin scales. However, almost no attempts have been made to explicitly accommodate interannual nutrient loading variability in their structure, despite empirical and theoretical evidence indicating that the associated source/sink processes are quite variable at annual timescales. In this study, we present two methodological approaches to accommodate interannual variability with the Spatially Referenced Regressions on Watershed attributes (SPARROW) nonlinear regression model. The first strategy uses the SPARROW model to estimate a static baseline load and climatic variables (e.g., precipitation) to drive the interannual variability. The second approach allows the source/sink processes within the SPARROW model to vary at annual timescales using dynamic parameter estimation techniques akin to those used in dynamic linear models. Model parameterization is founded upon Bayesian inference techniques that explicitly consider calibration data and model uncertainty. Our case study is the Hamilton Harbor watershed, a mixed agricultural and urban residential area located at the western end of Lake Ontario, Canada. Our analysis suggests that dynamic parameter estimation is the more parsimonious of the two strategies tested and can offer insights into the temporal structural changes associated with watershed functioning. Consistent with empirical and theoretical work, model estimated annual in-stream attenuation rates varied inversely with annual discharge. Estimated phosphorus source areas were concentrated near the receiving water body during years of high in-stream attenuation and dispersed along the main stems of the streams during years of low attenuation, suggesting that nutrient source areas are subject to interannual variability.

Impacts of transportation infrastructure on storm water and surfaces waters in Chittenden County, Vermont, USA.

DOT National Transportation Integrated Search

2014-06-01

Transportation infrastructure is a major source of stormwater runoff that can alter hydrology and : contribute significant loading of nutrients, sediment, and other pollutants to surface waters. These : increased loads can contribute to impairment of...

Monitoring Nitrate, Chlorophyll, and CDOM Cycling in a Reservoir using In Situ Mapping Techniques

NASA Astrophysics Data System (ADS)

OConnor, J.; Showers, W. J.; Osburn, C. L.; DeMaster, D. J.

2013-12-01

Degradation of surface waters due to increased nutrient loading and subsequent eutrophication is a persistent problem on a global scale. Expanding human populations and their associated development create increased pressure on local watersheds in terms of both point and non-point source pollution. In this study a suite of in situ sensors measuring nitrate concentration, chlorophyll a concentration (Chl a), and chromophoric dissolved organic material (CDOM) fluorescence were deployed from a rapidly moving boat (~32 km/h) in order to identify sources of nutrients and CDOM, and to determine their relationship to eutrophication symptoms in Falls Lake, North Carolina. In addition, water samples were collected throughout the lake and from tributaries of interest for laboratory analysis. Results indicated the three main tributaries at the north end of the lake were the important contributors of both nitrate and CDOM. While two of the three were degraded due to significant effluent discharge from Waste Water Treatment Plants, the third appeared to be impacted by diffuse nutrient sources. However, atmospheric deposition of nitrate and ammonium exceeded tributary input, and the net nutrient loading to the lake was dominated by sediment release of both ammonium and phosphate. No direct relationship between nitrate and Chl a concentrations was observed, but bays that sewage impacted rivers emptied into displayed elevated Chl a values. Water samples from both the lake and streams were analyzed for stable isotopic analysis of δ15N and δ18O composition and were consistent with waste as the primary source of nitrate. Samples were also analyzed for CDOM absorbance and fluorescence through the creation of Excitation and Emission Matrices (EEMs) and the development of a nine component PARAFAC model. Fluorescence values consistently declined from the north end of the lake to the southern end at the dam and water treatment plant intake. Absorbance values at 254 nm (a254) also showed a decreasing trend from north to south, while SR increased. The loss of absorption could have been caused by photobleaching, however, a hydrologic modeling experiment demonstrated that this change in optical character was actually due to mixing of un-polluted tributary and rain water with water from the main tributaries at the north end. At the southern end of the lake, adjacent to the water treatment plant intake, a series of depth profiles were made that revealed a stratified water column during summer months. There was evidence of production of CDOM in the anoxic hypolimnion that appeared to be linked to an increase in Chl a concentration. There was also a significant increase in a254 and a decrease in SR that suggested CDOM was released from the sediments in the hypolimnion. This study showed that the north end of the lake suffered from persistent eutrophication symptoms. However, as the water traveled south to the two exit points at the dam and the water treatment plant, water quality improved.

Characterization of domestic gray water from point source to determine the potential for urban residential reuse: a short review

NASA Astrophysics Data System (ADS)

Edwin, Golda A.; Gopalsamy, Poyyamoli; Muthu, Nandhivarman

2014-03-01

This study aims to discern the domestic gray water (GW) sources that is least polluting, at the urban households of India, by examining the GW characteristics, comparing with literature data, reuse standards and suitable treatment technologies. In view of this, the quantitative and qualitative characteristics of domestic GW originating from bath, wash basin, laundry and kitchen sources are determined and compared with established standards for reuse requirements. Quality of different gray water sources is characterized with respect to the physical, chemical, biological, nutrient, ground element and heavy metal properties. The pollutant loads indicate that the diversion techniques are not suitable for household application and, therefore, treatment is necessary prior to storage and reuse. It is observed that the total volume of GW generated exceeds the reuse requirement for suggested reuse such as for flushing and gardening/irrigation. In spite of generating less volume, the kitchen source is found to be the major contributor for most of the pollutant load and, therefore, not recommended to be considered for treatment. It is concluded that treatment of GW from bathroom source alone is sufficient to meet the onsite reuse requirements and thereby significantly reduce the potable water consumption by 28.5 %. Constructed wetland systems and constructed soil filters are suggested as suitable treatment alternatives owing to its ability to treat highly variable pollutant load with lower operational and maintenance cost, which is more practical for tropical and developing countries.

Analysis of non-point and point source pollution in China: case study in Shima Watershed in Guangdong Province

NASA Astrophysics Data System (ADS)

Fang, Huaiyang; Lu, Qingshui; Gao, Zhiqiang; Shi, Runhe; Gao, Wei

2013-09-01

China economy has been rapidly increased since 1978. Rapid economic growth led to fast growth of fertilizer and pesticide consumption. A significant portion of fertilizers and pesticides entered the water and caused water quality degradation. At the same time, rapid economic growth also caused more and more point source pollution discharge into the water. Eutrophication has become a major threat to the water bodies. Worsening environment problems forced governments to take measures to control water pollution. We extracted land cover from Landsat TM images; calculated point source pollution with export coefficient method; then SWAT model was run to simulate non-point source pollution. We found that the annual TP loads from industry pollution into rivers are 115.0 t in the entire watershed. Average annual TP loads from each sub-basin ranged from 0 to 189.4 ton. Higher TP loads of each basin from livestock and human living mainly occurs in the areas where they are far from large towns or cities and the TP loads from industry are relatively low. Mean annual TP loads that delivered to the streams was 246.4 tons and the highest TP loads occurred in north part of this area, and the lowest TP loads is mainly distributed in middle part. Therefore, point source pollution has much high proportion in this area and governments should take measures to control point source pollution.

Use of point-of-sale data to assess food and nutrient quality in remote stores.

PubMed

Brimblecombe, Julie; Liddle, Robyn; O'Dea, Kerin

2013-07-01

To examine the feasibility of using point-of-sale data to assess dietary quality of food sales in remote stores. A multi-site cross-sectional assessment of food and nutrient composition of food sales. Point-of-sale data were linked to Australian Food and Nutrient Data and compared across study sites and with nutrient requirements. Remote Aboriginal Australia. Six stores. Point-of-sale data were readily available and provided a low-cost, efficient and objective assessment of food and nutrient sales. Similar patterns in macronutrient distribution, food expenditure and key food sources of nutrients were observed across stores. In all stores, beverages, cereal and cereal products, and meat and meat products comprised approximately half of food sales (range 49–57 %). Fruit and vegetable sales comprised 10.4 (SD 1.9) % on average. Carbohydrate contributed 54.4 (SD 3.0) % to energy; protein 13.5 (SD 1.1) %; total sugars 28.9 (SD 4.3) %; and the contribution of total saturated fat to energy ranged from 11.0 to 14.4% across stores. Mg, Ca, K and fibre were limiting nutrients, and Na was four to five times higher than the midpoint of the average intake range. Relatively few foods were major sources of nutrients. Point-of-sale data enabled an assessment of dietary quality within stores and across stores with no burden on communities and at no cost, other than time required for analysis and reporting. Similar food spending patterns and nutrient profiles were observed across the six stores. This suggests potential in using point-of-sale data to monitor and evaluate dietary quality in remote Australian communities.

Rating curve estimation of nutrient loads in Iowa rivers

USGS Publications Warehouse

Stenback, G.A.; Crumpton, W.G.; Schilling, K.E.; Helmers, M.J.

2011-01-01

Accurate estimation of nutrient loads in rivers and streams is critical for many applications including determination of sources of nutrient loads in watersheds, evaluating long-term trends in loads, and estimating loading to downstream waterbodies. Since in many cases nutrient concentrations are measured on a weekly or monthly frequency, there is a need to estimate concentration and loads during periods when no data is available. The objectives of this study were to: (i) document the performance of a multiple regression model to predict loads of nitrate and total phosphorus (TP) in Iowa rivers and streams; (ii) determine whether there is any systematic bias in the load prediction estimates for nitrate and TP; and (iii) evaluate streamflow and concentration factors that could affect the load prediction efficiency. A commonly cited rating curve regression is utilized to estimate riverine nitrate and TP loads for rivers in Iowa with watershed areas ranging from 17.4 to over 34,600km2. Forty-nine nitrate and 44 TP datasets each comprising 5-22years of approximately weekly to monthly concentrations were examined. Three nitrate data sets had sample collection frequencies averaging about three samples per week. The accuracy and precision of annual and long term riverine load prediction was assessed by direct comparison of rating curve load predictions with observed daily loads. Significant positive bias of annual and long term nitrate loads was detected. Long term rating curve nitrate load predictions exceeded observed loads by 25% or more at 33% of the 49 measurement sites. No bias was found for TP load prediction although 15% of the 44 cases either underestimated or overestimate observed long-term loads by more than 25%. The rating curve was found to poorly characterize nitrate and phosphorus variation in some rivers. ?? 2010 .

Relations of surface-water quality to streamflow in the Hackensack, Passaic, Elizabeth, and Rahway River basins, New Jersey, water years 1976-93

USGS Publications Warehouse

Buxton, Debra E.; Hunchak-Kariouk, Kathryn; Hickman, R. Edward

1998-01-01

Relations of water quality to streamflow were determined for 18 water-quality constituents at 19 surface-water-quality stations within the drainage basins of the Hackensack, Passaic, Elizabeth, and Rahway Rivers in New Jersey for water years 1976-93. Surface-waterquality and streamflow data were evaluated for trends (through time) in constituent concentrations during high and low flows, and relations between constituent concentration and streamflow, and constituent load and streamflow, were determined. Median concentrations were calculated for the entire period of study (water years 1976-93) and for the last 5 years of the period of study (water years 1989-93) to determine whether any large variation in concentration exists between the two periods. Medians also were used to determine the seasonal Kendall’s tau statistic, which was then used to evaluate trends in concentrations during high and low flows.Trends in constituent concentrations during high and low flows were evaluated to determine whether the distribution of the observations changes over time for intermittent (nonpoint storm runoff) or constant (point sources and ground water) sources, respectively. Highand low-flow concentration trends were determined for some constituents at 11 of the 19 waterquality stations; 8 stations have insufficient data to determine trends. Seasonal effects on the relations of concentration to streamflow are evident for 16 of the 18 constituents. Negative slopes of relations of concentration to streamflow, which indicate a decrease in concentration at high flows, predominate over positive slopes because of dilution of instream concentrations from storm runoff.The slopes of the regression lines of load to streamflow were determined in order to show the relative contributions to the instream load from constant (point sources and ground water) and intermittent sources (storm runoff). Greater slope values suggest larger contributions from storm runoff to instream load, which most likely indicate an increased relative importance of nonpoint sources. Load-to-streamflow relations along a stream reach that tend to increase in a downstream direction indicate the increased relative importance of contributions from storm runoff. Likewise, load-to-streamflow relations along a stream reach that tend to decrease in a downstream direction indicate the increased relative importance of point sources and ground-water discharge. For most of the 18 constituents, load-to-streamflow relations at stations along a river reach remain constant or decrease in a downstream direction. The slopes increase in the downstream direction for some or all of the nutrient species at the Ramapo, lower Passaic, and Rahway Rivers; for dissolved solids, dissolved sodium, and dissolved chloride at the lower Passaic River; and for alkalinity and hardness at the Rahway River.

NutrientNet: An Internet-Based Approach to Teaching Market-Based Policy for Environmental Management

ERIC Educational Resources Information Center

Nguyen, To N.; Woodward, Richard T.

2009-01-01

NutrientNet is an Internet-based environment in which a class can simulate a market-based approach for improving water quality. In NutrientNet, each student receives a role as either a point source or a nonpoint source polluter, and then the participants are allowed to trade water quality credits to cost-effectively reduce pollution in a…

Nutrient production from dairy cattle manure and loading on arable land.

PubMed

Won, Seunggun; Shim, Soo-Min; You, Byung-Gu; Choi, Yoon-Seok; Ra, Changsix

2017-01-01

Along with increasing livestock products via intensive rearing, the accumulation of livestock manure has become a serious issue due to the fact that there is finite land for livestock manure recycling via composting. The nutrients from livestock manure accumulate on agricultural land and the excess disembogues into streams causing eutrophication. In order to systematically manage nutrient loading on agricultural land, quantifying the amount of nutrients according to their respective sources is very important. However, there is a lack of research concerning nutrient loss from livestock manure during composting or storage on farms. Therefore, in the present study we quantified the nutrients from dairy cattle manure that were imparted onto agricultural land. Through investigation of 41 dairy farms, weight reduction and volatile solids (VS), total nitrogen (TN), and total phosphorus (TP) changes of dairy cattle manure during the storage and composting periods were analyzed. In order to support the direct investigation and survey on site, the three cases of weight reduction during the storing and composting periods were developed according to i) experiment, ii) reference, and iii) theoretical changes in phosphorus content (ΔP = 0). The data revealed the nutrient loading coefficients (NLCs) of VS, TN, and TP on agricultural land were 1.48, 0.60, and 0.66, respectively. These values indicated that the loss of nitrogen and phosphorus was 40% and 34%, respectively, and that there was an increase of VS since bedding materials were mixed with excretion in the barn. As result of nutrient-footprint analyses, the amounts of TN and TP particularly entered on arable land have been overestimated if applying the nutrient amount in fresh manure. The NLCs obtained in this study may assist in the development of a database to assess the accurate level of manure nutrient loading on soil and facilitate systematic nutrient management.

Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States

USGS Publications Warehouse

Rebich, R.A.; Houston, N.A.; Mize, S.V.; Pearson, D.K.; Ging, P.B.; Evan, Hornig C.

2011-01-01

SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

Water-quality assessment of the Albemarle-Pamlico drainage basin, North Carolina and Virginia; characterization of suspended sediment, nutrients, and pesticides

USGS Publications Warehouse

Harned, Douglas; McMahon, Gerard; Spruill, T.B.; Woodside, M.D.

1995-01-01

The 28,000-square-mile Albemarle-Pamlico drainage basin includes the Roanoke, Dan, Chowan Tar, and Neuse Rivers. The basin extends through four physiographic provinces in North Carolina and Virginia-Valley and Ridge, Blue Ridge, Piedmont and Coastal Plain. The spatial and temporal trends in ground-water and riverine water quality in the study area were characterized by using readily available data sources The primary data sources that were used included the U.S. Geological Survey's National Water Data Storage and Retrieval System (WATSTORE) database, the U.S. Environmental Protection Agency's Storage and Retrieval System (STORET) database, and results of a few investigations of pesticide occurrence. The principal water-quality constituents examined were suspended sediment, nutrients, and pesticides. The data examined generally spanned the period from 1950 to 1993. The only significant trends in suspended sediment were detected at three Chowan River tributary sites which showed long-term decreases. Suspended- and total-solids concentrations have decreased throughout the Albemarle-Pamlico drainage basin. The decreases are probably a result of (1) construction of new lakes and ponds in the basin, which trap solids, (2) improved agricultural soil management, and (3) improved wastewater treatment. Nutrient point sources are much less than nonpoint nutrient sources at the eight NASQAN basins examined for nutrient loads. The greatest nitrogen inputs are associated with crop fertilizer and biological nitrogen fixation by soybeans and peanuts, whereas atmospheric and animal-related nitrogen inputs are comparable in magnitude. The largest phosphorus inputs are associated with animal wastes. The most commonly detected pesticides in surface water in the STORET database were atrazine and aldrin.Intensive organonitrogen herbicide sampling of Chicod Creek in 1992 showed seasonal variations in pesticide concentration. The most commonly detected herbicides were atrazine, alachlor, metolachlor, prometon, and metribuzin. No relation between streamflow and pesticide concentration was evident.

A framework and a set of tools called Nutting models to estimate retention capacities and loads of nitrogen and phosphorus in rivers at catchment and national level (France)

NASA Astrophysics Data System (ADS)

Legeay, Pierre-Louis; Moatar, Florentina; Dupas, Rémi; Gascuel-Odoux, Chantal

2016-04-01

The Nutting-N and Nutting-P models (Dupas et al., 2013, 2015) have been developed to estimate Nitrogen and Phosphorus nonpoint-source emissions to surface water, using readily available data. These models were inspired from US model SPARROW (Smith al., 1997) and European model GREEN (Grizzetti et al., 2008), i.e. statistical approaches consisting of linking nitrogen and phosphorus surplus to catchment's land and rivers characteristics to find the catchment relative retention capacities. The nutrient load (L) at the outlet of each catchment is expressed as: L=R*(B*DS+PS) [1] where DS is diffuse sources (i.e. surplus in kg.ha-1/yr-1 for N, P storage in soil for P), PS is point sources from domestic and industrial origin (kg.ha-1.yr-1), R and B are the river system and basin reduction factor, respectively and they combine observed variables and calibrated parameters. The model was calibrated on independent catchments for the 2005-2009 and 2008-2012 periods. Variables were selected according to Bayesian Information Criterion (BIC) in order to optimize the predictive performance of the models. From these basic models, different improvements have been realized to build a framework and a set of tools: 1) a routing module has been added in order to improve estimations on 4 or 5 stream order, i.e. upscaling the basic Nutting approach; 2) a territorial module, in order to test the models at local scale (from 500 to 5000 km²); 3) a seasonal estimation has been investigated. The basic approach as well territorial application will be illustrated. These tools allow water manager to identify areas at risk where high nutrients loads are estimated, as well areas where retention is potentially high and can buffer high nutrient sources. References Dupas R., Curie F., Gascuel-Odoux C., Moatar F., Delmas M., Parnaudeau, V., Durand P., 2013. Assessing N emissions in surface water at the national level: Comparison of country-wide vs. regionalized models. Science of the Total Environment 443, 152-162 Dupas R., Delmas M., Dorioz J.M., Garnier J., Moatar F., Gascuel-Odoux C., 2015. Assessing the impact of agricultural pressures on N and P loads andeutrophication risk. Ecological Indicators 48, 396-407. Grizzetti B., Bouraoui F., De Marsily G., 2008. Assessing nitrogen pressures on European surface water. Global Biogeochemical Cycles; 22. Smith R.A., Schwarz G.E., Alexander R.B., 1997. Regional interpretation of water-quality monitoring data. Water Resources Research 1997; 33: 2781-2798.

Identification of Geologic and Anthropogenic Sources of Phosphorus to Streams in California and Portions of Adjacent States, U.S.A., Using SPARROW Modeling

NASA Astrophysics Data System (ADS)

Domagalski, J. L.

2013-12-01

The SPARROW (Spatially Referenced Regressions On Watershed Attributes) model allows for the simulation of nutrient transport at un-gauged catchments on a regional scale. The model was used to understand natural and anthropogenic factors affecting phosphorus transport in developed, undeveloped, and mixed watersheds. The SPARROW model is a statistical tool that allows for mass balance calculation of constituent sources, transport, and aquatic decay based upon a calibration of a subset of stream networks, where concentrations and discharge have been measured. Calibration is accomplished using potential sources for a given year and may include fertilizer, geological background (based on bed-sediment samples and aggregated with geochemical map units), point source discharge, and land use categories. NHD Plus version 2 was used to model the hydrologic system. Land to water transport variables tested were precipitation, permeability, soil type, tile drains, and irrigation. For this study area, point sources, cultivated land, and geological background are significant phosphorus sources to streams. Precipitation and clay content of soil are significant land to water transport variables and various stream sizes show significance with respect to aquatic decay. Specific rock types result in different levels of phosphorus loading and watershed yield. Some important geological sources are volcanic rocks (andesite and basalt), granodiorite, glacial deposits, and Mesozoic to Cenozoic marine deposits. Marine sediments vary in their phosphorus content, but are responsible for some of the highest natural phosphorus yields, especially along the Central and Southern California coast. The Miocene Monterey Formation was found to be an especially important local source in southern California. In contrast, mixed metamorphic and igneous assemblages such as argillites, peridotite, and shales of the Trinity Mountains of northern California result in some of the lowest phosphorus yields. The agriculturally productive Central Valley of California has a low amount of background phosphorus in spite of inputs from streams draining upland areas. Many years of intensive agriculture may be responsible for the decrease of soil phosphorus in that area. Watersheds with significant background sources of phosphorus and large amounts of cultivated land had some of the highest per hectare yields. Seven different stream systems important for water management, or to describe transport processes, were investigated in detail for downstream changes in sources and loads. For example, the Klamath River (Oregon and California) has intensive agriculture and andesite-derived phosphorus in the upper reach. The proportion of agricultural-derived phosphorus decreases as the river flows into California before discharge to the ocean. The river flows through at least three different types of geological background sources from high to intermediate to very low. Knowledge of the role of natural sources in developed watersheds is critical for developing nutrient management strategies and these model results will have applicability for the establishment of realistic nutrient criteria.

Water quality and hydrology of Silver Lake, Oceana County, Michigan, with emphasis on lake response to nutrient loading

USGS Publications Warehouse

Brennan, Angela K.; Hoard, Christopher J.; Duris, Joseph W.; Ogdahl, Mary E.; Steinman, Alan D.

2016-01-29

Simulations also were run using the BATHTUB model to evaluate the number of days Silver Lake could experience algal blooms (algal blooms are defined as modeled chlorophyll a in excess of 10 micrograms per liter [µg/L]) as a result of an increase/decrease in phosphorus and nitrogen loading from groundwater, Hunter Creek, and (or) a combination of sources. If the phosphorus and nitrogen loading from Hunter Creek is decreased (and all other sources are not altered), Silver Lake will continue to experience algal blooms, but less frequently than what is currently experienced. The same scenario holds true if the nutrient loading from groundwater is decreased. Another scenario was simulated using a combination of sources, which includes increases and decreases in phosphorus and nitrogen loading from sources that are the most likely to be managed, and includes groundwater (as a result of conversion of household septic to sewers), Hunter Creek (conversion of household septic to sewers), and lawn runoff. Results of the BATHTUB model indicated that a 50-percent reduction of phosphorus and nitrogen from these sources would result in a considerable decrease in algal bloom frequency (from 231 to 132 days) and severity, and a 75-percent reduction would greatly reduce algal bloom occurrence on Silver Lake (from 231 to 57 days). BATHTUB model scenarios based on septic load model: A scenario also was conducted using the BATHTUB model to simulate the conversion of septic to sewer and included a low, high, and medium (likely) scenario of nutrient loading to Silver Lake. Simulations of the BATHTUB model indicated that, under the likely scenario, the conversion of all onsite septic treatment to sewers would result in an overall change in lake trophic status from eutrophic to mesotrophic, thereby reducing the frequency of algal blooms and algal bloom intensity on Silver Lake (chlorophyll a >10 µg/L, from 231 to 184 days per year, or chlorophyll a >20 µg/L, from 80 to 49 days per year).

Nutrients and water masses in the Gulf of Maine - Georges Bank region: Variability and importance to blooms of the toxic dinoflagellate Alexandrium fundyense.

PubMed

Townsend, D W; McGillicuddy, D J; Thomas, M A; Rebuck, N R

2014-05-01

We report here the results of ten oceanographic survey cruises carried out in the Gulf of Maine - Georges Bank region of the Northwest Atlantic during the late spring to summer period in 2007, 2008 and 2010, for which we examine and characterize relationships among dissolved inorganic nutrient fields, water mass dynamics and cell densities of the toxic dinoflagellate Alexandrium fundyense . Nutrients are supplied to continental shelf waters of the Gulf of Maine - Georges Bank region by inflows of deep offshore water masses; once in the Gulf they are transported with the residual circulation and mix with surface waters, both in the Gulf and on the Bank. Those fluxes of offshore water masses and their nutrient loads are the major source of nutrients for phytoplankton production in the region, including annual blooms of A. fundyense in the Gulf and on Georges Bank. This much is already known. We suggest here that the locations and magnitude of A. fundyense blooms are controlled in part by variable nutrient fluxes to the interior Gulf of Maine from offshore, and, those interior Gulf of Maine waters are, in turn, the main nutrient source to Georges Bank, which are brought onto the Bank by tidal pumping on the Northern Flank. We present evidence that nitrate is the initial form of nitrogenous nutrient for A. fundyense blooms, but it is quickly depleted to limiting concentrations of less than 0.5 μM, at which time continued growth and maintenance of the population is likely fueled by recycled ammonium. We also show that phosphate may be the limiting nutrient over much of Georges Bank in summer, allowing recycled ammonium concentrations to increase. Our temperature-salinity analyses reveal spatial and temporal (seasonal and interannual) variability in the relative proportions of two deep source waters that enter the Gulf of Maine at depth through the Northeast Channel: Warm Slope Water (WSW) and Labrador Slope Water (LSW). Those two source waters are known to vary in their nutrient loads, with nitrate concentrations about 50% higher in WSW than LSW, for example, and as such the proportions of these two water masses to one another are important determinants of the overall nutrient loads in the interior Gulf. In addition to these deep slope water fluxes, we show evidence here of episodic fluxes of relatively fresh and low-nutrient shelf waters from the Nova Scotian Shelf, which enter the Gulf in pulses at depths between the surface and approximately 150 m, displacing deep slope waters, and consequently they significantly dilute the Gulf's interior waters, reducing nutrient concentrations and, in turn, affect the magnitude of A. fundyense blooms.

Nutrients and water masses in the Gulf of Maine - Georges Bank region: Variability and importance to blooms of the toxic dinoflagellate Alexandrium fundyense

PubMed Central

Townsend, D.W.; McGillicuddy, D.J.; Thomas, M.A.; Rebuck, N.R.

2015-01-01

We report here the results of ten oceanographic survey cruises carried out in the Gulf of Maine - Georges Bank region of the Northwest Atlantic during the late spring to summer period in 2007, 2008 and 2010, for which we examine and characterize relationships among dissolved inorganic nutrient fields, water mass dynamics and cell densities of the toxic dinoflagellate Alexandrium fundyense. Nutrients are supplied to continental shelf waters of the Gulf of Maine - Georges Bank region by inflows of deep offshore water masses; once in the Gulf they are transported with the residual circulation and mix with surface waters, both in the Gulf and on the Bank. Those fluxes of offshore water masses and their nutrient loads are the major source of nutrients for phytoplankton production in the region, including annual blooms of A. fundyense in the Gulf and on Georges Bank. This much is already known. We suggest here that the locations and magnitude of A. fundyense blooms are controlled in part by variable nutrient fluxes to the interior Gulf of Maine from offshore, and, those interior Gulf of Maine waters are, in turn, the main nutrient source to Georges Bank, which are brought onto the Bank by tidal pumping on the Northern Flank. We present evidence that nitrate is the initial form of nitrogenous nutrient for A. fundyense blooms, but it is quickly depleted to limiting concentrations of less than 0.5 μM, at which time continued growth and maintenance of the population is likely fueled by recycled ammonium. We also show that phosphate may be the limiting nutrient over much of Georges Bank in summer, allowing recycled ammonium concentrations to increase. Our temperature-salinity analyses reveal spatial and temporal (seasonal and interannual) variability in the relative proportions of two deep source waters that enter the Gulf of Maine at depth through the Northeast Channel: Warm Slope Water (WSW) and Labrador Slope Water (LSW). Those two source waters are known to vary in their nutrient loads, with nitrate concentrations about 50% higher in WSW than LSW, for example, and as such the proportions of these two water masses to one another are important determinants of the overall nutrient loads in the interior Gulf. In addition to these deep slope water fluxes, we show evidence here of episodic fluxes of relatively fresh and low-nutrient shelf waters from the Nova Scotian Shelf, which enter the Gulf in pulses at depths between the surface and approximately 150 m, displacing deep slope waters, and consequently they significantly dilute the Gulf's interior waters, reducing nutrient concentrations and, in turn, affect the magnitude of A. fundyense blooms. PMID:26028824

Effects of Land Use Land Cover (LULC) and Climate on Simulation of Phosphorus loading in the Southeast United States Region

NASA Astrophysics Data System (ADS)

Jima, T. G.; Roberts, A.

2013-12-01

Quality of coastal and freshwater resources in the Southeastern United States is threatened due to Eutrophication as a result of excessive nutrients, and phosphorus is acknowledged as one of the major limiting nutrients. In areas with much non-point source (NPS) pollution, land use land cover and climate have been found to have significant impact on water quality. Landscape metrics applied in catchment and riparian stream based nutrient export models are known to significantly improve nutrient prediction. The regional SPARROW (Spatially Referenced Regression On Watershed attributes), which predicts Total Phosphorus has been developed by the Southeastern United States regions USGS, as part of the National Water Quality Assessment (NAWQA) program and the model accuracy was found to be 67%. However, landscape composition and configuration metrics which play a significant role in the source, transport and delivery of the nutrient have not been incorporated in the model. Including these matrices in the models parameterization will improve the models accuracy and improve decision making process for mitigating and managing NPS phosphorus in the region. The National Land Cover Data 2001 raster data will be used (since the base line is 2002) for the region (with 8321 watersheds ) with fragstats 4.1 and ArcGIS Desktop 10.1 for the analysis of landscape matrices, buffers and creating map layers. The result will be imported to the Southeast SPARROW model and will be analyzed. Resulting statistical significance and model accuracy will be assessed and predictions for those areas with no water quality monitoring station will be made.

Impact of forecasted changes in Polish economy (2015 and 2020) on nutrient emission into the river basins.

PubMed

Pastuszak, Marianna; Kowalkowski, Tomasz; Kopiński, Jerzy; Stalenga, Jarosław; Panasiuk, Damian

2014-09-15

Poland, with its large drainage area, with 50% contribution of agricultural land and 45% contribution of population to overall agricultural land area and population number in the Baltic catchment, is the largest exporter of riverine nitrogen (N) and phosphorus (P) to the sea. The economic transition has resulted in substantial, statistically significant decline in N, P export from Polish territory to the Baltic Sea. Following the obligations arising from the Helsinki Commission (HELCOM) declarations, in the coming years, Poland is expected to reduce riverine N loads by ca. 25% and P loads by ca. 60% as referred to the average flow normalized loads recorded in 1997-2003. The aim of this paper is to estimate annual source apportioned N and P emissions into these river basins in 2015 and 2020 with application of modeling studies (MONERIS). Twelve scenarios, encompassing changes in anthropogenic (diffuse, point source) and natural pressure (precipitation, water outflow due to climate change), have been applied. Modeling outcome for the period 2003-2008 served as our reference material. In applied scenarios, N emission into the Oder basin in 2015 and 2020 shows an increase from 4.2% up to 9.1% as compared with the reference period. N emission into the Vistula basin is more variable and shows an increase by max. 17.8% or a decrease by max. 4.7%, depending on the scenario. The difference between N emission into the Oder and Vistula basins is related to the catchment peculiarities and handling of point sources emission. P emission into both basins shows identical scenario patters and a maximum decrease reaches 17.8% in the Oder and 16.7% in the Vistula basin. Despite a declining tendency in P loads in both rivers in all the scenarios, HELCOM targeted P load reduction is not feasible. Copyright © 2014 Elsevier B.V. All rights reserved.

Opening the black box: evaluation of nutrient nonpoint source management for estuarine watersheds

EPA Science Inventory

Over the last 40 years, there have been significant improvements in water quality and ecosystem condition in estuaries stressed by nutrient enrichment. However, documented improvements have been largely attributed to reductions in point sources. In contrast, improvement of coasta...

Nutrient mitigation in a temporary river basin.

PubMed

Tzoraki, Ourania; Nikolaidis, Nikolaos P; Cooper, David; Kassotaki, Elissavet

2014-04-01

We estimate the nutrient budget in a temporary Mediterranean river basin. We use field monitoring and modelling tools to estimate nutrient sources and transfer in both high and low flow conditions. Inverse modelling by the help of PHREEQC model validated the hypothesis of a losing stream during the dry period. Soil and Water Assessment Tool model captured the water quality of the basin. The 'total daily maximum load' approach is used to estimate the nutrient flux status by flow class, indicating that almost 60% of the river network fails to meet nitrogen criteria and 50% phosphate criteria. We recommend that existing well-documented remediation measures such as reforestation of the riparian area or composting of food process biosolids should be implemented to achieve load reduction in close conjunction with social needs.

The Potential Importance of Conservation, Restoration and Altered Management Practices for Water Quality in the Wabash River Watershed

NASA Astrophysics Data System (ADS)

Yang, G.; Best, E. P.; Goodwin, S.

2013-12-01

Non-point source (NPS) pollution is one of the leading causes of water quality impairment within the United States. Conservation, restoration and altered management (CRAM) practices may effectively reduce NPS pollutants to receiving water bodies and enhance local and regional ecosystem services. Barriers for the implementation of CRAM include uncertainties related to the extent to which nutrients are removed by CRAM at various spatial and temporal scales, longevity, optimal placement of CRAM within the landscape, and implementation / operation / maintenance costs. We conducted a study aimed at the identification of optimal placement of CRAM in watersheds that reduces N loading to an environmentally sustainable level, at an acceptable, known, cost. For this study, we used a recently developed screening-level modeling approach, WQM-TMDL-N, running in the ArcGIS environment, to estimate nitrogen loading under current land use conditions (NLCD 2006). This model was equipped with a new option to explore the performances of placement of various CRAM types and areas to reduce nitrogen loading to a State-accepted Total Maximum Daily Load (TMDL) standard, with related annual average TN concentration, and a multi-objective algorithm optimizing load and cost. CRAM practices explored for implementation in rural area included buffer strips, nutrient management practices, and wetland restoration. We initially applied this modeling approach to the Tippecanoe River (TR) watershed (8-digit HUC), a headwater of the Wabash River (WR) watershed, where CRAM implementation in rural and urban areas is being planned and implemented at various spatial scales. Consequences of future land use are explored using a 2050 land use/land cover map forecasted by the Land Transformation Model. The WR watershed, IN, drains two-thirds of the state's 92 counties and supports predominantly agricultural land use. Because the WR accounts for over 40% of the nutrient loads of the Ohio River and significantly contributes to the anoxic zone in the Gulf of Mexico (GOM), reduction in TN loading of the WR are expected to directly benefit downstream ecosystem services, including fisheries in the GOM. This modeling approach can be used in support of sustainable integrated watershed management planning.

Modelling nutrient fluxes from diffuse and point emissions to river loads: the Estonian part of the transboundary Lake Peipsi/Chudskoe drainage basin (Russia/Estonia/Latvia).

PubMed

Mourad, D; van der Perk, M

2004-01-01

First results are presented of a large-scale GIS-based nutrient transport modelling for the 1985-1999 period in the Estonian part of the transboundary drainage basin of Lake Peipsi (Estonian)/Chudskoe (Russian), one of the largest lakes in Europe, shared by Russia and Estonia. Although the lake is relatively undisturbed by human pollution, it is vulnerable for eutrophication by increased river loads, as shown in the past, when the north-eastern part of the former Soviet Union suffered from intensive agriculture. The collapse of the Soviet Union caused a dramatic decline in fertilizer application rates and widespread abandonment of agricultural land. Although concentration measurements and modelling results indicate a general decrease in nutrient loads, modelling is complicated by the transfer of nutrients from diffuse emissions, which is strongly governed by retention and assumed periodic release from storages within the river basin, like the root zone, tile drains, ditches, channels, bed sediments, floodplains and lakes. Modelling diffuse emission contribution to river loads can be improved by better knowledge about the spatial and temporal distribution of this retention and release within the drainage basin.

Incentive Analysis for Clean Water Act Reauthorization: Point Source/Nonpoint Source Trading for Nutrient Discharge Reductions (1992)

EPA Pesticide Factsheets

Paper focuses on trading schemes in which regulated point sources are allowed to avoid upgrading their pollution control technology to meet water quality-based effluent limits if they pay for equivalent (or greater) reductions in nonpoint source pollution.

Spatiotemporal patterns and source attribution of nitrogen pollution in a typical headwater agricultural watershed in Southeastern China.

PubMed

Chen, Wenjun; He, Bin; Nover, Daniel; Duan, Weili; Luo, Chuan; Zhao, Kaiyan; Chen, Wen

2018-01-01

Excessive nitrogen (N) discharge from agriculture causes widespread problems in aquatic ecosystems. Knowledge of spatiotemporal patterns and source attribution of N pollution is critical for nutrient management programs but is poorly studied in headwaters with various small water bodies and mini-point pollution sources. Taking a typical small watershed in the low mountains of Southeastern China as an example, N pollution and source attribution were studied for a multipond system around a village using the Hydrological Simulation Program-Fortran (HSPF) model. The results exhibited distinctive spatio-seasonal variations with an overall seriousness rank for the three indicators: total nitrogen (TN) > nitrate/nitrite nitrogen (NO x - -N) > ammonia nitrogen (NH 3 -N), according to the Chinese Surface Water Quality Standard. TN pollution was severe for the entire watershed, while NO x - -N pollution was significant for ponds and ditches far from the village, and the NH 3 -N concentrations were acceptable except for the ponds near the village in summer. Although food and cash crop production accounted for the largest source of N loads, we discovered that mini-point pollution sources, including animal feeding operations, rural residential sewage, and waste, together contributed as high as 47% of the TN and NH 3 -N loads in ponds and ditches. So, apart from eco-fertilizer programs and concentrated animal feeding operations, the importance of environmental awareness building for resource management is highlighted for small farmers in headwater agricultural watersheds. As a first attempt to incorporate multipond systems into the process-based modeling of nonpoint source (NPS) pollution, this work can inform other hydro-environmental studies on scattered and small water bodies. The results are also useful to water quality improvement for entire river basins.

Silage storage runoff characterization: Annual nutrient loading rate and first flush analysis of bunder silos

USDA-ARS?s Scientific Manuscript database

Silage runoff produced during the preservation and storage of dairy forage in horizontal bunkers is a source of nutrient loss from the farmstead and a threat to surface water quality. This research evaluated the runoff characteristics from six dairy bunker facilities to determine runoff water qualit...

Impact of macropores and gravel outcrops on phosphorus leaching at the plot scale in silt loam soils

USDA-ARS?s Scientific Manuscript database

In response to increased nutrient loads in surface waters, scientists and engineers need to identify critical nutrient source areas and transport mechanisms within a catchment to protect beneficial uses of aquatic systems in a cost effective manner. It was hypothesized that hydrologic heterogeneitie...

Evaluation of nutrient retention in vegetated filter strips using the SWAT model.

PubMed

Elçi, Alper

2017-11-01

Nutrient fluxes in stream basins need to be controlled to achieve good water quality status. In stream basins with intensive agricultural activities, nutrients predominantly come from diffuse sources. Therefore, best management practices (BMPs) are increasingly implemented to reduce nutrient input to streams. The objective of this study is to evaluate the impact of vegetated filter strip (VFS) application as an agricultural BMP. For this purpose, SWAT is chosen, a semi-distributed water quality assessment model that works at the watershed scale, and applied on the Nif stream basin, a small-sized basin in Western Turkey. The model is calibrated with an automated procedure against measured monthly discharge data. Nutrient loads for each sub-basin are estimated considering basin-wide data on chemical fertilizer and manure usage, population data for septic tank effluents and information about the land cover. Nutrient loads for 19 sub-basins are predicted on an annual basis. Average total nitrogen and total phosphorus loads are estimated as 47.85 t/yr and 13.36 t/yr for the entire basin. Results show that VFS application in one sub-basin offers limited retention of nutrients and that a selection of 20-m filter width is most effective from a cost-benefit perspective.

Utilization of solid catfish manure waste as carbon and nutrient source for lactic acid production.

PubMed

Shi, Suan; Li, Jing; Blersch, David M

2018-06-01

The aim of this work was to study the solid waste (manure) produced by catfish as a potential feedstock for the production of lactic acid (LA) via fermentation. The solid waste contains high levels of both carbohydrates and nutrients that are sufficient for LA bacteria. Simultaneous saccharification and co-fermentation (SSCF) was applied using enzyme and Lactobacillus pentosus, and different loadings of enzyme and solid waste were tested. Results showed LA concentrations of 35.7 g/L were obtained at 15% solids content of catfish waste. Because of the high nutrient content in the fish waste, it could also be used as supplementary substrate for nitrogen and carbon sources with other lignocellulosic materials. A combined feedstock of catfish waste and paper mill sludge was tested, increasing the final LA concentration to 43.1 g/L at 12% solids loading. The catfish waste was shown to be a potential feedstock to provide both carbon and nutrients for LA production, suggesting its use as a sole substrate or in combination with other lignocellulosic materials.

Simulation of flow and water quality of the Arroyo Colorado, Texas, 1989-99

USGS Publications Warehouse

Raines, Timothy H.; Miranda, Roger M.

2002-01-01

A model parameter set for use with the Hydrological Simulation Program—FORTRAN watershed model was developed to simulate flow and water quality for selected properties and constituents for the Arroyo Colorado from the city of Mission to the Laguna Madre, Texas. The model simulates flow, selected water-quality properties, and constituent concentrations. The model can be used to estimate a total maximum daily load for selected properties and constituents in the Arroyo Colorado. The model was calibrated and tested for flow with data measured during 1989–99 at three streamflow-gaging stations. The errors for total flow volume ranged from -0.1 to 29.0 percent, and the errors for total storm volume ranged from -15.6 to 8.4 percent. The model was calibrated and tested for water quality for seven properties and constituents with 1989–99 data. The model was calibrated sequentially for suspended sediment, water temperature, biochemical oxygen demand, dissolved oxygen, nitrate nitrogen, ammonia nitrogen, and orthophosphate. The simulated concentrations of the selected properties and constituents generally matched the measured concentrations available for the calibration and testing periods. The model was used to simulate total point- and nonpoint-source loads for selected properties and constituents for 1989–99 for urban, natural, and agricultural land-use types. About one-third to one-half of the biochemical oxygen demand and nutrient loads are from urban point and nonpoint sources, although only 13 percent of the total land use in the basin is urban.

Managing Saginaw Bay nutrient loading by surrounding watersheds through near real time hydrologic resource sheds

EPA Science Inventory

We can quantify source areas contributing material to a location during various time periods as resource sheds. Various kinds of resource sheds and their source material distributions are defined. For watershed hydrology, we compute resource sheds and their source material distri...

Long-term atmospheric deposition of nitrogen, phosphorus and sulfate in a large oligotrophic lake

PubMed Central

Craft, James A.; Stanford, Jack A.

2015-01-01

We documented significantly increasing trends in atmospheric loading of ammonium (NH4) and nitrate/nitrite (NO2/3) and decreasing trends in total phosphorus (P) and sulfate (SO4) to Flathead Lake, Montana, from 1985 to 2004. Atmospheric loading of NO2/3 and NH4 increased by 48 and 198% and total P and SO4 decreased by 135 and 39%. The molar ratio of TN:TP also increased significantly. Severe air inversions occurred periodically year-round and increased the potential for substantial nutrient loading from even small local sources. Correlations between our loading data and various measures of air quality in the basin (e.g., particulate matter <10 µm in size, aerosol fine soil mass, aerosol nutrient species, aerosol index, hectares burned) suggest that dust and smoke are important sources. Ammonium was the primary form of N in atmospheric deposition, whereas NO3 was the primary N form in tributary inputs. Atmospheric loading of NH4 to Flathead Lake averaged 44% of the total load and on some years exceeded tributary loading. Primary productivity in the lake is colimited by both N and P most of the year; and in years of high atmospheric loading of inorganic N, deposition may account for up to 6.9% of carbon converted to biomass. PMID:25802810

Long-term atmospheric deposition of nitrogen, phosphorus and sulfate in a large oligotrophic lake.

PubMed

Ellis, Bonnie K; Craft, James A; Stanford, Jack A

2015-01-01

We documented significantly increasing trends in atmospheric loading of ammonium (NH4) and nitrate/nitrite (NO2/3) and decreasing trends in total phosphorus (P) and sulfate (SO4) to Flathead Lake, Montana, from 1985 to 2004. Atmospheric loading of NO2/3 and NH4 increased by 48 and 198% and total P and SO4 decreased by 135 and 39%. The molar ratio of TN:TP also increased significantly. Severe air inversions occurred periodically year-round and increased the potential for substantial nutrient loading from even small local sources. Correlations between our loading data and various measures of air quality in the basin (e.g., particulate matter <10 µm in size, aerosol fine soil mass, aerosol nutrient species, aerosol index, hectares burned) suggest that dust and smoke are important sources. Ammonium was the primary form of N in atmospheric deposition, whereas NO3 was the primary N form in tributary inputs. Atmospheric loading of NH4 to Flathead Lake averaged 44% of the total load and on some years exceeded tributary loading. Primary productivity in the lake is colimited by both N and P most of the year; and in years of high atmospheric loading of inorganic N, deposition may account for up to 6.9% of carbon converted to biomass.

Effects of anthropogenic nitrogen input on the aquatic food webs of river ecosystem in central Japan

NASA Astrophysics Data System (ADS)

Ohte, N.; Togashi, H.; Tokuchi, N.; Yoshimura, M.; Kato, Y.; Ishikawa, N. F.; Osaka, K.; Kondo, M.; Tayasu, I.

2014-12-01

To evaluate the impact of the anthropogenic nitrogen input to the river ecosystem, we conducted the monitoring on nutrient status of river waters and food web structures of aquatic organisms. Especially, changes of sources and concentration of nitrate (NO3-) in river water were focused to evaluate the impact of anthropogenic nitrogen loadings from agricultural and residential areas. Stable nitrogen isotope ratio (δ15N) of aquatic organisms has also intensively been monitored not only to describe their food web structure, but also to detect the influences of extraneous nitrogen inputs. Field samplings an observation campaigns were conducted in the Arida river watershed located in central part of Japan at four different seasons from September 2011 to October 2012. Five observation points were set from headwaters to the point just above the brackish waters starts. Water samples for chemical analysis were taken at the observation points for each campaign. Organisms including leaf litters, benthic algae, aquatic insects, crustacean, and fishes were sampled at each point quantitatively. Results of the riverine survey utilizing 5 regular sampling points showed that δ15N of nitrate (NO3-) increased from forested upstream (˜2 ‰) to the downstream (˜7 ‰) due to the sewage loads and fertilizer effluents from agricultural area. Correspondingly the δ15N of benthic algae and aquatic insects increased toward the downstream. This indicates that primary producers of each reach strongly relied on the local N sources and it was utilized effectively in their food web. Simulation using a GIS based mixing model considering the spatial distributions of human population density and fertilizer effluents revealed that strongest impacts of N inputs was originated from organic fertilizers applied to orchards in the middle to lower parts of catchment. Differences in δ15N between primary producers and predators were 6-7 ‰ similarly at all sampling points. Food web structural analysis using food network unfolding technique based on observed δ15N suggested that the structure of nutrient pyramid did not differ significantly along the riverine positions, while the members of species in each trophic revel changed and the impact of anthropogenic N input was visible along the river.

Benthic nutrient sources to hypereutrophic upper Klamath Lake, Oregon, USA.

PubMed

Kuwabara, James S; Topping, Brent R; Lynch, Dennis D; Carter, James L; Essaid, Hedeff I

2009-03-01

Three collecting trips were coordinated in April, May, and August 2006 to sample the water column and benthos of hypereutrophic Upper Klamath Lake (OR, USA) through the annual cyanophyte bloom of Aphanizomenon flos-aquae. A pore-water profiler was designed and fabricated to obtain the first high-resolution (centimeter-scale) estimates of the vertical concentration gradients of macro- and micronutrients for diffusive-flux determinations. A consistently positive benthic flux for soluble reactive phosphorus (SRP) was observed with solute release from the sediment, ranging between 0.4 and 6.1 mg/m(2)/d. The mass flux over an approximate 200-km(2) lake area was comparable in magnitude to riverine inputs. An additional concern related to fish toxicity was identified when dissolved ammonium also displayed consistently positive benthic fluxes of 4 to 134 mg/m(2)/d, again comparable to riverine inputs. Although phosphorus was a logical initial choice by water quality managers for the limiting nutrient when nitrogen-fixing cyanophytes dominate, initial trace-element results from the lake and major inflowing tributaries suggested that the role of iron limitation on primary productivity should be investigated. Dissolved iron became depleted in the lake water column during the course of the algal bloom, while dissolved ammonium and SRP increased. Elevated macroinvertebrate densities, at least of the order of 10(4) individuals/m(2), suggested that the diffusive-flux estimates may be significantly enhanced by bioturbation. In addition, heat-flux modeling indicated that groundwater advection of nutrients could also significantly contribute to internal nutrient loading. Accurate environmental assessments of lentic systems and reasonable expectations for point-source management require quantitative consideration of internal solute sources.

Benthic nutrient sources to hypereutrophic Upper Klamath Lake, Oregon, USA

USGS Publications Warehouse

Kuwabara, J.S.; Topping, B.R.; Lynch, D.D.; Carter, J.L.; Essaid, H.I.

2009-01-01

Three collecting trips were coordinated in April, May, and August 2006 to sample the water column and benthos of hypereutrophic Upper Klamath Lake (OR, USA) through the annual cyanophyte bloom of Aphanizomenon flos-aquae. A porewater profiler was designed and fabricated to obtain the first high-resolution (centimeter-scale) estimates of the vertical, concentration gradients of macro- and micronutrients for diffusive-flux determinations. A consistently positive benthic flux for soluble reactive phosphorus (SRP) was observed with solute release from the sediment, ranging between 0.4 and 6.1 mg/m2/d. The mass flux over an approximate 200-km2 lake area was comparable in magnitude to riverine inputs. An additional concern, related to fish toxicity was identified when dissolved ammonium also displayed consistently positive benthic fluxes of 4 to 134 mg/m2/d, again, comparable to riverine inputs. Although phosphorus was a logical initial choice by water quality managers for the limiting nutrient when nitrogen-fixing cyanophytes dominate, initial trace-element results from the lake and major inflowing tributaries suggested that the role of iron limitation on primary productivity should be investigated. Dissolved iron became depleted in the lake water column during the course of the algal bloom, while dissolved ammonium and SRP increased. Elevated macroinvertebrate densities, at least of the order of 104 individuals/m2, suggested, that the diffusive-flux estimates may be significantly enhanced, by bioturbation. In addition, heat-flux modeling indicated that groundwater advection of nutrients could also significantly contribute to internal nutrient loading. Accurate environmental assessments of lentic systems and reasonable expectations for point-source management require quantitative consideration of internal solute sources ?? 2009 SETAC.

Eutrophication study at the Panjiakou-Daheiting Reservoir system, northern Hebei Province, People's Republic of China: Chlorophyll-a model and sources of phosphorus and nitrogen

USGS Publications Warehouse

Domagalski, Joseph L.; Lin, Chao; Luo, Yang; Kang, Jie; Wang, Shaoming; Brown, Larry R.; Munn, Mark D.

2007-01-01

Concentrations, loads, and sources of nitrate and total phosphorus were investigated at the Panjiakou and Daheiting Reservoir system in northern Hebei Province, People's Republic of China. The Luan He River is the primary source of water to these reservoirs, and the upstream watershed has a mix of land uses including agriculture, forest, and one large urban center. The reservoirs have a primary use for storage of drinking water and partially supply Tianjin City with its annual needs. Secondary uses include flood control and aqua culture (fish cages). The response of the reservoir system from phosphorus input, with respect to chlorophyll-a production from algae, was fitted to a model of normalized phosphorus loading that regresses the average summer-time chlorophyll-a concentration to the average annual phosphorus concentration of the reservoir. Comparison of the normalized phosphorus loading and chlorophyll-a response of this system to other reservoirs throughout the world indicate a level of eutrophication that will require up to an approximate 5–10-fold decrease in annual phosphorus load to bring the system to a more acceptable level of algal productivity. Isotopes of nitrogen and oxygen in dissolved nitrate were measured from the headwater streams and at various locations along the major rivers that provide the majority of water to these reservoirs. Those isotopic measurements indicate that the sources of nitrate change from natural background in the rivers to animal manure and septic waste upstream of the reservoir. Although the isotopic measurements suggest that animal and septic wastes are a primary source of nutrients, measurements of the molar ratio of nitrogen to phosphorus are more indicative of row-cropping practices. Options for reduction of nutrient loads include changing the management practices of the aqua culture, installation of new sewage treatment systems in the large urbanized area of the upper watershed, and agricultural management practices that would reduce the loading of nutrients and soil erosion from that land use.

Land application of spent gypsum from ditch filters: phosphorus source or sink?

USDA-ARS?s Scientific Manuscript database

Agricultural drainage ditches can provide a direct connection between fields and surface waters, and some have been shown to deliver high loads of phosphorus (P) to sensitive water bodies. A potential way to reduce nutrient loads in drainage ditches is to install filter structures containing P sorbi...

Review of Phosphorus Control Measures in the United States and Their Effects on Water Quality

USGS Publications Warehouse

Litke, David W.

1999-01-01

Historical information on phosphorus loadings to the environment and the effect on water quality are summarized in this report, which was produced as part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program. Phosphorus is a water-quality constituent of concern because it is often the limiting nutrient responsible for accelerated eutrophication in water bodies. Phosphorus inputs to the environment have increased since 1950 as the use of phosphate fertilizer, manure, and phosphate laundry detergent increased; however, the manufacture of phosphate detergent for household laundry was ended voluntarily in about 1994 after many States had established phosphate detergent bans. Total phosphorus concentrations in raw wastewater effluent contained about 3 milligrams per liter of total phosphorus during the 1940's, increased to about 11 milligrams per liter at the height of phosphate detergent use (1970), and have currently declined to about 5 milligrams per liter. However, in some cases, tertiary wastewater treatment still is needed to effectively improve water quality of streams. Downward trends in phosphorus concentrations since 1970 have been identified in many streams, but median total phosphorus concentrations still exceed the recommended limit of 0.1 milligram per liter across much of the Nation. Data from the NAWQA Program are representative of a variety of phosphorus-control measures, and, therefore, may be used to evaluate the effects of various control strategies. Current areas of concern include: evaluation of the effects of increased manure loadings of phosphorus on soil phosphorus and, subsequently, on ground water and subsurface runoff; determination of point-source and nonpoint-source components of phosphorus loads by geographic modeling and hydrologic separation techniques; and development of methods or indices to evaluate nutrient impairment in streams and rivers to serve as a basis for developing phosphorus criteria or standards.

County-level estimates of nutrient inputs to the landsurface of the conterminous United States, 1982-2001

USGS Publications Warehouse

Ruddy, Barbara C.; Lorenz, David L.; Mueller, David K.

2006-01-01

Nutrient input data for fertilizer use, livestock manure, and atmospheric deposition from various sources were estimated and allocated to counties in the conterminous United States for the years 1982 through 2001. These nationally consistent nutrient input data are needed by the National Water-Quality Assessment Program for investigations of stream- and ground-water quality. For nitrogen, the largest source was farm fertilizer; for phosphorus, the largest sources were farm fertilizer and livestock manure. Nutrient inputs from fertilizer use in nonfarm areas, while locally important, were an order of magnitude smaller than inputs from other sources. Nutrient inputs from all sources increased between 1987 and 1997, but the relative proportions of nutrients from each source were constant. Farm-fertilizer inputs were highest in the upper Midwest, along eastern coastal areas, and in irrigated areas of the West. Nonfarm-fertilizer use was similar in major metropolitan areas throughout the Nation, but was more extensive in the more populated Eastern and Central States and in California. Areas of greater manure inputs were located throughout the South-central and Southeastern States and in scattered areas of the West. Nitrogen deposition from the atmosphere generally increased from west to east and is related to the location of major sources and the effects of precipitation and prevailing winds. These nutrient-loading data at the county level are expected to be the fundamental basis for national and regional assessments of water quality for the National Water-Quality Assessment Program and other large-scale programs.

An integrated modeling approach for estimating the water quality benefits of conservation practices at the river basin scale.

PubMed

Santhi, C; Kannan, N; White, M; Di Luzio, M; Arnold, J G; Wang, X; Williams, J R

2014-01-01

The USDA initiated the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of conservation practices at regional and national scales. For this assessment, a sampling and modeling approach is used. This paper provides a technical overview of the modeling approach used in CEAP cropland assessment to estimate the off-site water quality benefits of conservation practices using the Ohio River Basin (ORB) as an example. The modeling approach uses a farm-scale model, Agricultural Policy Environmental Extender (APEX), and a watershed scale model (the Soil and Water Assessment Tool [SWAT]) and databases in the Hydrologic Unit Modeling for the United States system. Databases of land use, soils, land use management, topography, weather, point sources, and atmospheric depositions were developed to derive model inputs. APEX simulates the cultivated cropland, Conserve Reserve Program land, and the practices implemented on them, whereas SWAT simulates the noncultivated land (e.g., pasture, range, urban, and forest) and point sources. Simulation results from APEX are input into SWAT. SWAT routes all sources, including APEX's, to the basin outlet through each eight-digit watershed. Each basin is calibrated for stream flow, sediment, and nutrient loads at multiple gaging sites and turned in for simulating the effects of conservation practice scenarios on water quality. Results indicate that sediment, nitrogen, and phosphorus loads delivered to the Mississippi River from ORB could be reduced by 16, 15, and 23%, respectively, due to current conservation practices. Modeling tools are useful to provide science-based information for assessing existing conservation programs, developing future programs, and developing insights on load reductions necessary for hypoxia in the Gulf of Mexico. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Changes in distributional patterns of plaice Pleuronectes platessa in the central and eastern North Sea; do declining nutrient loadings play a role?

NASA Astrophysics Data System (ADS)

Støttrup, Josianne G.; Munk, Peter; Kodama, Masashi; Stedmon, Colin

2017-09-01

Since the beginning of the 1990s, there has been a change in the relative distribution of smaller age-classes of plaice Pleuronectes platessa (age 1-3) in the North Sea. The abundances have increased in deeper, more offshore areas, while coastal abundances have been stagnant or declining. For the same time period available time series data on nutrient conditions in the coastal North Sea area show that the freshwater nitrogen loading has decreased by about 50%. While nutrient concentrations in the ambient environment have been shown to influence growth in juvenile plaice through influence on their prey, we here inspect the potential linkage between distributional changes in plaice and the decline in nutrient loading. We compare plaice observations in coastal areas in the eastern North Sea, which have experienced large changes in eutrophication, with observations for the Dogger Bank, a large sandbank in a shallow offshore area of the North Sea. The Dogger Bank, was used as a reference location assuming this area has been less influenced from coastal eutrophication but similar regional climate conditions, and here we found no changes in the abundances of juvenile plaice. The increase in the use of offshore habitats as nursery areas by juvenile plaice in the North Sea appears not related to water depth per se but driven by specific processes dominating in near-shore areas and may be related to changes in nutrient loadings. This point to the importance of separating more general depth-related factors from conditions specific for near-shore areas, such as nutrient loadings in coastal waters and export offshore. The concurrent changes in environment and in distribution of juvenile plaice may have implications for environmental and fisheries management.

Submarine groundwater discharge as an important nutrient source influencing nutrient structure in coastal water of Daya Bay, China

NASA Astrophysics Data System (ADS)

Wang, Xuejing; Li, Hailong; Zheng, Chunmiao; Yang, Jinzhong; Zhang, Yan; Zhang, Meng; Qi, Zhanhui; Xiao, Kai; Zhang, Xiaolang

2018-03-01

As an important nutrient source for coastal waters, submarine groundwater discharge (SGD) has long been largely ignored in Daya Bay, China. In this study, we estimate the fluxes of SGD and associated nutrients into this region using a 224Ra mass balance model and assess the contribution/importance of nutrients by SGD, benthic sediments, local rivers, and atmospheric deposition. The results of 224Ra mass balance show that the estimated SGD ranges from (2.76 ± 1.43) × 106 m3/d to (1.03 ± 0.53) × 107 m3/d with an average of (6.32 ± 2.42) × 106 m3/d, about 16 times the total discharge rate of local rivers. The nutrient loading from SGD is estimated to be (1.05-1.99) × 105 mol/d for NO3-N, (4.04-12.16) × 103 mol/d for DIP, and (3.54-11.35) × 105 mol/d for Si. Among these considered nutrient sources, we find that SGD is the primary source for Si and NO3-N, contributing 68% and 42% of all considered sources, respectively. The atmospheric NO3-N flux is comparable to that from SGD. The local rivers are the most important source for DIP, contributing 75% of all considered sources. SGD with high N:P ratio (NO3-N/DIP) of 37.0 delivers not only a large quantity of nutrients, but also changes nutrient structure in coastal water. Based on a DIP budget, primary productivity is evaluated to be 54-73 mg C/m2 d, in which SGD accounts for approximately 30% of total production. This study indicates that SGD is a key source of nutrients to coastal waters and may cause an obvious change of primary production and nutrient structure in Daya Bay.

Two tales of legacy effects on stream nutrient behaviour

NASA Astrophysics Data System (ADS)

Bieroza, M.; Heathwaite, A. L.

2017-12-01

Intensive agriculture has led to large-scale land use conversion, shortening of flow pathways and increased loads of nutrients in streams. This legacy results in gradual build-up of nutrients in agricultural catchments: in soil for phosphorus (biogeochemical legacy) and in the unsaturated zone for nitrate (hydrologic legacy), controlling the water quality in the long-term. Here we investigate these effects on phosphorus and nitrate stream concentrations using high-frequency (10-5 - 100 Hz) sampling with in situ wet-chemistry analysers and optical sensors. Based on our 5 year study, we observe that storm flow responses differ for both nutrients: phosphorus shows rapid increases (up to 3 orders of magnitude) in concentrations with stream flow, whereas nitrate shows both dilution and concentration effects with increasing flow. However, the range of nitrate concentrations change is narrow (up to 2 times the mean) and reflects chemostatic behaviour. We link these nutrient responses with their dominant sources and flow pathways in the catchment. Nitrate from agriculture (with the peak loading in 1983) is stored in the unsaturated zone of the Penrith Sandstone, which can reach up to 70 m depth. Thus nitrate legacy is related to a hydrologic time lag with long travel times in the unsaturated zone. Phosphorus is mainly sorbed to soil particles, therefore it is mobilised rapidly during rainfall events (biogeochemical legacy). The phosphorus stream response will however depend on how well connected is the stream to the catchment sources (driven by soil moisture distribution) and biogeochemical activity (driven by temperature), leading to both chemostatic and non-chemostatic responses, alternating on a storm-to-storm and seasonal basis. Our results also show that transient within-channel storage is playing an important role in delivery of phosphorus, providing an additional time lag component. These results show, that consistent agricultural legacy in the catchment (high historical loads of nutrients) has different effects on nutrients stream responses, depending on their dominant sources and pathways. Both types of time lags, biogeochemical for phosphorus and hydrologic for nitrate, need to be taken into account when designing and evaluating the effectiveness of the agri-environmental mitigation measures.

Assessing the spatial and temporal variations of water quality in lowland areas, Northern Germany

NASA Astrophysics Data System (ADS)

Lam, Q. D.; Schmalz, B.; Fohrer, N.

2012-05-01

SummaryThe pollution of rivers and streams with agro-chemical contaminants has become one of the most crucial environmental problems in the world. The assessment of spatial and temporal variations of water quality influenced by point and diffuse source pollution is necessary to manage the environment sustainably in various watershed scales. The overall objectives of this study were to assess the transferability of parameter sets between lowland catchments on different scales using the ecohydrological model SWAT (Soil and Water Assessment Tool) and to evaluate the temporal and spatial patterns of water quality in the whole catchments before and after implementation of best management practices (BMPs). The study area Kielstau catchment is located in Northern Germany as typical example of lowland - flood plain landscape. Sandy, loamy and peat soils are characteristic for this area. Land use is dominated by arable land and pasture. In this study we examined two catchment areas including Kielstau catchment 50 km2 and its subcatchment, namely Moorau, with the area of 7.6 km2. The water quality of these catchments is not only influenced by diffuse sources from agricultural areas but also by point sources from municipal wastewater treatment plants (WWTPs). Diffuse sources as well as punctual entries from the WWTPs are considered in the model set-up. For this study, the calibration and validation of the model were carried out in a daily time step for flow and nutrients. The results indicate that the parameter sets could be transferred in lowland catchments with similar environmental conditions. Shallow groundwater is the major contributor to total nitrate load in the stream accounting for about 93% of the total nitrate load, while only about 7% originates in surface runoff and lateral flow. The study also indicates that applying a spatially distributed modeling approach was an appropriate method to generate source maps showing the spatial distribution of TN load from hydrologic response units (HRUs) as well as from subbasins and to identify the crucial pollution areas within a watershed whose management practices can be improved to control more effectively nitrogen loading to water bodies.

Temporal and spatial trends in nutrient and sediment loading to Lake Tahoe, California-Nevada, USA

USGS Publications Warehouse

Coats, Robert; Lewis, Jack; Alvarez, Nancy L.; Arneson, Patricia

2016-01-01

Since 1980, the Lake Tahoe Interagency Monitoring Program (LTIMP) has provided stream-discharge and water quality data—nitrogen (N), phosphorus (P), and suspended sediment—at more than 20 stations in Lake Tahoe Basin streams. To characterize the temporal and spatial patterns in nutrient and sediment loading to the lake, and improve the usefulness of the program and the existing database, we have (1) identified and corrected for sources of bias in the water quality database; (2) generated synthetic datasets for sediments and nutrients, and resampled to compare the accuracy and precision of different load calculation models; (3) using the best models, recalculated total annual loads over the period of record; (4) regressed total loads against total annual and annual maximum daily discharge, and tested for time trends in the residuals; (5) compared loads for different forms of N and P; and (6) tested constituent loads against land use-land cover (LULC) variables using multiple regression. The results show (1) N and P loads are dominated by organic N and particulate P; (2) there are significant long-term downward trends in some constituent loads of some streams; and (3) anthropogenic impervious surface is the most important LULC variable influencing water quality in basin streams. Many of our recommendations for changes in water quality monitoring and load calculation methods have been adopted by the LTIMP.

Impacts of urban wastewater discharge on seagrass meadows ( Zostera noltii)

NASA Astrophysics Data System (ADS)

Cabaço, Susana; Machás, Raquel; Vieira, Vasco; Santos, Rui

2008-06-01

The abiotic disturbance of urban wastewater discharge and its effects in the population structure, plant morphology, leaf nutrient content, epiphyte load and macroalgae abundance of Zostera noltii meadows were investigated in Ria Formosa coastal lagoon, southern Portugal using both univariate and multivariate analysis. Four sites were assessed, on a seasonal basis, along a gradient from a major Waste Water Treatment Works (WWTW) discharge to a main navigation channel. The wastewater discharge caused an evident environmental disturbance through the nutrient enrichment of the water and sediment, particularly of ammonium. Zostera noltii of the sites closest to the nutrient source showed higher leaf N content, clearly reflecting the nitrogen load. The anthropogenic nutrient enrichment resulted in higher biomass, and higher leaf and internode length, except for the meadow closest to the wastewater discharge (270 m). The high ammonium concentration (158-663 μM) in the water at this site resulted in the decrease of biomass, and both the leaf and internode length, suggesting a toxic effect on Z. noltii. The higher abundance of macroalgae and epiphytes found in the meadow closest to the nutrient source may also affect the species negatively. Shoot density was higher at the nutrient-undisturbed site. Two of the three abiotic processes revealed by Principal Component Analysis were clearly related to the WWTW discharge, a contrast between water column salinity and nutrient concentration and a sediment contrast between both porewater nutrients and temperature and redox potential. A multiple regression analysis showed that these abiotic processes had a significant effect on the biomass-density dynamics of meadows and on the overall size of Z. noltii plants, respectively. Results show that the wastewater discharge is an important source of environmental disturbance and nutrients availability in Ria Formosa lagoon affecting the population structure, morphology and N content of Z. noltii. This impact is spatially restricted to areas up to 600 m distant from the WWTW discharge, probably due to the high water renewal of the lagoon.

Nutrient production from dairy cattle manure and loading on arable land

PubMed Central

You, Byung-Gu; Choi, Yoon-Seok; Ra, Changsix

2017-01-01

Objective Along with increasing livestock products via intensive rearing, the accumulation of livestock manure has become a serious issue due to the fact that there is finite land for livestock manure recycling via composting. The nutrients from livestock manure accumulate on agricultural land and the excess disembogues into streams causing eutrophication. In order to systematically manage nutrient loading on agricultural land, quantifying the amount of nutrients according to their respective sources is very important. However, there is a lack of research concerning nutrient loss from livestock manure during composting or storage on farms. Therefore, in the present study we quantified the nutrients from dairy cattle manure that were imparted onto agricultural land. Methods Through investigation of 41 dairy farms, weight reduction and volatile solids (VS), total nitrogen (TN), and total phosphorus (TP) changes of dairy cattle manure during the storage and composting periods were analyzed. In order to support the direct investigation and survey on site, the three cases of weight reduction during the storing and composting periods were developed according to i) experiment, ii) reference, and iii) theoretical changes in phosphorus content (ΔP = 0). Results The data revealed the nutrient loading coefficients (NLCs) of VS, TN, and TP on agricultural land were 1.48, 0.60, and 0.66, respectively. These values indicated that the loss of nitrogen and phosphorus was 40% and 34%, respectively, and that there was an increase of VS since bedding materials were mixed with excretion in the barn. Conclusion As result of nutrient-footprint analyses, the amounts of TN and TP particularly entered on arable land have been overestimated if applying the nutrient amount in fresh manure. The NLCs obtained in this study may assist in the development of a database to assess the accurate level of manure nutrient loading on soil and facilitate systematic nutrient management. PMID:27492346

Temporal variability in domestic point source discharges and their associated impact on receiving waters.

PubMed

Richards, Samia; Withers, Paul J A; Paterson, Eric; McRoberts, Colin W; Stutter, Marc

2016-11-15

Discharges from the widely distributed small point sources of pollutants such as septic tanks contribute to microbial and nutrient loading of streams and can pose risks to human health and stream ecology, especially during periods of ecological sensitivity. Here we present the first comprehensive data on the compositional variability of septic tank effluents (STE) as a potential source of water pollution during different seasons and the associated links to their influence on stream waters. To determine STE parameters and nutrient variations, the biological and physicochemical properties of effluents sampled quarterly from 12 septic tank systems were investigated with concurrent analyses of upstream and downstream receiving waters. The study revealed that during the warmer dryer months of spring and summer, effluents were similar in composition, as were the colder wetter months of autumn and winter. However, spring/summer effluents differed significantly (P<0.05) from autumn/winter for concentrations of biological oxygen demand (BOD), arsenic, barium (Ba), cobalt, chromium, manganese, strontium (Sr), titanium, tungsten (W) and zinc (Zn). With the exception of BOD, Ba and Sr which were greater in summer and spring, the concentrations of these parameters were greater in winter. Receiving stream waters also showed significant seasonal variation (P≤0.05) in alkalinity, BOD, dissolved organic carbon, sulphate, sulphur, lithium, W, Zn and Escherichiacoli abundance. There was a clear significant influence of STE on downstream waters relative to upstream from the source (P<0.05) for total suspended solids, total particulate P and N, ammonium-N, coliforms and E. coli. The findings of this study found seasonal variation in STE and place effluent discharges as a factor affecting adjacent stream quality and call for appropriate measures to reduce or redirect STE discharges away from water courses. Copyright © 2016 Elsevier B.V. All rights reserved.

A prototype for understanding the effects of TMDL standards: Tying property values to sediment loads in the Lake Tahoe Basin

USGS Publications Warehouse

Tracy, J.C.; Bernknopf, R.; Forney, W.; Hill, K.

2004-01-01

The Federal Clean Water Act (Section 303(d)) mandates that states develop Total Maximum Daily Load (TMDL) plans for water bodies that are on the Section 303(d) list. To be placed on the 303(d) list, a water body must be found to have water quality conditions that limit its ability to meet its designated beneficial uses. The TMDL for a water body is defined in 40 CFR 130 as the sum of waste load allocations from identified points sources and non-point sources within the water body's watershed. The TMDL plan for a listed water body should identify the current waste loads to the water body, the waste load capacity of the water body and then allocate the waste load capacity to the known point and non-point sources of pollution within the water body's watershed. Copyright 2004 ASCE.

The Onset of a Novel Environmental Offset: A case study for diverse pollutant scheme in Australia.

NASA Astrophysics Data System (ADS)

Sengupta, A.; Arora, M.; Delbridge, N.; Pettigrove, V.; Feldman, D.

2014-12-01

Environmental offset schemes employ a crediting system to mitigate the impacts of pollutants. In this talk, we present a novel trade-off concept comparing diverse groups of pollutants: environmental flows, micropollutants (heavy metals, pesticides, estrogen compounds) and nutrients in a test watershed (Jacksons Creek), in the vicinity of Melbourne. A reservoir in the upper watershed, and a wastewater treatment plant (WTP) are the main sources of flow into Jacksons Creek. The current land use is a mix of agriculture, and rural, though rapid urbanization is anticipated with a 40% increase in the population by 2040. The creek is impacted by: 1) low flow, especially during dry periods (contribution from the reservoir drops dramatically), 2) nutrient enrichment (WTP and agricultural runoff), and 3) micropollutants-heavy metals (urban runoff), estrogenic compounds (WTP), and pesticides (agricultural runoff). In this offset framework, we evaluated current and future scenarios to identify the main stressor in Jacksons Creek. We collected monitoring data at 15 sites for separate 3 events. Then we developed a watershed model to assess sources of pollutant loads to the creek, using two different tools, Model for Urban Stormwater Improvement Conceptualisation (MUSIC) for the preliminary flow and water quality modeling, and eWater Source for integrated water resource management (IWRM), and a decision support system for stakeholders. Scenario analysis includes urbanization and population growth, and anticipated discharges from WTP and the reservoir. Measured nutrient concentrations were high for all sampling events. Micropollutants were detected at a concentration higher than the trigger value at several locations. Preliminary analysis shows that low flow is one of the major stressors in the creek causing elevated micropollutant and nutrient concentrations (non-point), and that discharge from the WTP is essential to maintain the minimum environmental flows, though nutrient enrichment downstream could occur. This study demonstrates an innovative case for evaluating net environmental benefits, and might hold important lessons for the design of offset schemes in comparable environments elsewhere.

Predicting nitrogen loading with land-cover composition: how can watershed size affect model performance?

PubMed

Zhang, Tao; Yang, Xiaojun

2013-01-01

Watershed-wide land-cover proportions can be used to predict the in-stream non-point source pollutant loadings through regression modeling. However, the model performance can vary greatly across different study sites and among various watersheds. Existing literature has shown that this type of regression modeling tends to perform better for large watersheds than for small ones, and that such a performance variation has been largely linked with different interwatershed landscape heterogeneity levels. The purpose of this study is to further examine the previously mentioned empirical observation based on a set of watersheds in the northern part of Georgia (USA) to explore the underlying causes of the variation in model performance. Through the combined use of the neutral landscape modeling approach and a spatially explicit nutrient loading model, we tested whether the regression model performance variation over the watershed groups ranging in size is due to the different watershed landscape heterogeneity levels. We adopted three neutral landscape modeling criteria that were tied with different similarity levels in watershed landscape properties and used the nutrient loading model to estimate the nitrogen loads for these neutral watersheds. Then we compared the regression model performance for the real and neutral landscape scenarios, respectively. We found that watershed size can affect the regression model performance both directly and indirectly. Along with the indirect effect through interwatershed heterogeneity, watershed size can directly affect the model performance over the watersheds varying in size. We also found that the regression model performance can be more significantly affected by other physiographic properties shaping nitrogen delivery effectiveness than the watershed land-cover heterogeneity. This study contrasts with many existing studies because it goes beyond hypothesis formulation based on empirical observations and into hypothesis testing to explore the fundamental mechanism.

Predicting Ecosystem Services in Northeastern Lakes From Monitoring Data and USGS SPARROW Nutrient Load Estimates

EPA Science Inventory

Reduction of nitrogen inputs to estuaries can be achieved by the control of agricultural, atmospheric, and urban sources. We use the USGS MRB1 SPARROW model to estimate reductions necessary to decrease nitrogen loads to estuaries by 10%. As a first approximation we looked at s...

The combined impact of land use change and aquaculture on sediment and water quality in oligotrophic Lake Rupanco (North Patagonia, Chile, 40.8°S).

PubMed

León-Muñoz, Jorge; Echeverría, Cristian; Marcé, Rafael; Riss, Wolfgang; Sherman, Bradford; Iriarte, Jose Luis

2013-10-15

Water and sediment quality in North Patagonia's large, oligotrophic lakes are expected to suffer as native forest continues to be fragmented and degraded by its conversion to cropping and pasture land uses. These changes in land use are expected to increase diffuse nutrient loads to the region's lakes. In addition, these lakes are home to the world's second largest salmon aquaculture industry which provides additional point sources of nutrients within the lakes. We studied the combined influences of land use change and salmon farming on the nutrient concentrations in a North Patagonian lake (Lake Rupanco, 233 km(2) water surface, 163 m average depth) in four sub-watersheds ranging in disturbance from near-pristine forest to 53% converted to cropping and pasture. Nitrogen exports from the tributary sub-watersheds increased from 33 kg TN/km(2)/y to 621 kg TN/km(2)/y as the proportion of crop and pasture land increased. The combined nutrient load from land use change and salmon farming has led to significant differences in the nitrogen concentrations of the lake's water column and sediments in the near-shore zones across the lake. Total nitrogen concentrations in the sediments varied from 37 ± 18 mg/kg in near-pristine sub-watersheds without salmon farming to 6400 ± 698 mg/kg where the sub-watershed was dominated by crop and pasture lands combined with the presence of salmon farming. These results demonstrate the importance of considering the impacts of both salmon farming and land use on water and sediment quality for future environmental planning, management and decision making. Copyright © 2013 Elsevier Ltd. All rights reserved.

Streamflow and nutrients from a karst watershed with a downstream embayment: Chapel Branch Creek

Treesearch

Thomas M. Williams; Devendra M. Amatya; Daniel R. Hitchcock; Amy E. Edwards

2014-01-01

Understanding sources of streamflow and nutrient concentrations are fundamental for the assessment of pollutant loadings that can lead to water quality impairments. The objective of this study was to evaluate the discharge of three main tributaries, draining different land uses with karst features, as well as their combined influences on total nitrogen (TN) and total...

Calculation and analysis of the non-point source pollution in the upstream watershed of the Panjiakou Reservoir, People's Republic of China

NASA Astrophysics Data System (ADS)

Zhang, S.; Tang, L.

2007-05-01

Panjiakou Reservoir is an important drinking water resource in Haihe River Basin, Hebei Province, People's Republic of China. The upstream watershed area is about 35,000 square kilometers. Recently, the water pollution in the reservoir is becoming more serious owing to the non-point pollution as well as point source pollution on the upstream watershed. To effectively manage the reservoir and watershed and develop a plan to reduce pollutant loads, the loading of non-point and point pollution and their distribution on the upstream watershed must be understood fully. The SWAT model is used to simulate the production and transportation of the non-point source pollutants in the upstream watershed of the Panjiakou Reservoir. The loadings of non-point source pollutants are calculated for different hydrologic years and the spatial and temporal characteristics of non-point source pollution are studied. The stream network and topographic characteristics of the stream network and sub-basins are all derived from the DEM by ArcGIS software. The soil and land use data are reclassified and the soil physical properties database file is created for the model. The SWAT model was calibrated with observed data of several hydrologic monitoring stations in the study area. The results of the calibration show that the model performs fairly well. Then the calibrated model was used to calculate the loadings of non-point source pollutants for a wet year, a normal year and a dry year respectively. The time and space distribution of flow, sediment and non-point source pollution were analyzed depending on the simulated results. The comparison of different hydrologic years on calculation results is dramatic. The loading of non-point source pollution in the wet year is relatively larger but smaller in the dry year since the non-point source pollutants are mainly transported through the runoff. The pollution loading within a year is mainly produced in the flood season. Because SWAT is a distributed model, it is possible to view model output as it varies across the basin, so the critical areas and reaches can be found in the study area. According to the simulation results, it is found that different land uses can yield different results and fertilization in rainy season has an important impact on the non- point source pollution. The limitations of the SWAT model are also discussed and the measures of the control and prevention of non- point source pollution for Panjiakou Reservoir are presented according to the analysis of model calculation results.

Inferring nutrient loading of estuarine systems by remote sensing of aquatic vegetation

NASA Technical Reports Server (NTRS)

Anderson, R. R.

1978-01-01

THe use of remote sensing to record algal and vascular aquatic plant growths in estuarine waters is discussed. A technique is proposed that uses a combination of data to hierarchically classify watersheds with regard to severity of potential pollution. Specific nonpoint sources of nutrients in tributaries of the watershed are identified with lower altitude photography of vegetation and selected ground sampling. It is concluded that excessive growths of some aquatic plants may be related to nutrient pollution.

Occurrence of phosphorus, other nutrients, and triazine herbicides in water from the Hillsdale Lake basin, Northeast Kansas, May 1994 through May 1995

USGS Publications Warehouse

Putnam, J.E.

1997-01-01

An investigation of the occurrence of phosporus, other nutrients, and triazine herbicides in water samples from the Hillsdale Lake Basin in northeast Kansas was conducted from May 1994 through May 1995. Point-source and nonpoint-source contributions of these water-quality constituents were estimated by conducting synoptic sampling at 48 sites in the basin during five periods of low- flow conditions. Samples were collected for the determination of nutrients, including total phosphorus as phosphorus, dissolved orthophosphate as phosphorus, total nitrite plus nitrate as nitrogen, and total ammonia plus organic nitrogen as nitrogen, and for selected triazine herbicides. On the basis of criteria developed by the Kansas Department of Health and Environment, the Hillsdale Water-Quality Protection Project established a goal to maintain water quality in the tributaries of the Hillsdale Lake Basin at a mean annual low-flow total phosphorus concentration of 0.05 mg/L (milligrams per liter). The mean low- flow total phosphorus concentration of water samples collected in the Big Bull Creek (which includes drainage from Martin Creek), Rock Creek, Little Bull Creek, Wade Branch, and Smith Branch subbasins during low-flow conditions ranged from 0.05 to 4.9 mg/L during this study. Of the 44 sites sampled during low flow, 95 percent had low-flow total phosphorus concentrations larger than the 0.05-mg/L criterion. Discharges from wastewater- treatment plants located in Big Bull Creek and Martin Creek subbasins and the Little Bull Creek subbasin affected nutrient concentrations. Nutrient concentrations in water samples collected from the subbasins not affected by point-source discharges generally were smaller than those in the Big Bull Creek and Little Bull Creek subbasins. Estimated annual low-flow phosphorus loads computed at sampling sites located at the outlet of the subbasins show that the Big Bull Creeksubbasin, which includes drainage from the Martin Creek subbasin, had the largest estimate annual low-flow load, 2,740 kg/yr (kilograms per year).Rock Creek, Little Bull Creek, Wade Branch, and Smith Branch subbasins contributed less annual low-flow phosphorus load, 175, 161, 234, and 22kg/yr, respectively. With the exception of the Smith Branch subbasin, the largest triazine herbicide concentrations occurred in water samples collectedduring May 1994 and May 1995. During May 1994, 10 of 17 sampling sites in the Big Bull Creek and Martin Creek subbasins, 5 of 6 sites in theRock Creek subbasin, and 4 of 10 sites in the Little Bull Creek subbasin had triazine herbicide concentrations in water larger than the U.S.Environmental Protection Agency's Maximum Contaminant Level (MCL), which is an annual mean 3.0 ug/L (micrograms per liter) for atrazine indrinking water. During May 1995, 7 of 19 sites in the Big Bull Creek and Martin Creek subbasins, 5 of 6 sites in the Rock Creek subbasin, 1 of 12 sites in the Little Bull Creek subbasin, and 2 of 4 sites in the Wade Branch subbasin had samples with trazine herbicide concentrations larger than the MCL.Water samples collected in the Rock Creek subbasins had the largest mean triazine herbicide concentrations during May 1994 and May 1995, 6.4 and 4.5 ug/L, respectively.

Nutrient delivery to Lake Winnipeg from the Red-Assiniboine River Basin – A binational application of the SPARROW model

USGS Publications Warehouse

Benoy, Glenn A.; Jenkinson, R. Wayne; Robertson, Dale M.; Saad, David A.

2016-01-01

Excessive phosphorus (TP) and nitrogen (TN) inputs from the Red–Assiniboine River Basin (RARB) have been linked to eutrophication of Lake Winnipeg; therefore, it is important for the management of water resources to understand where and from what sources these nutrients originate. The RARB straddles the Canada–United States border and includes portions of two provinces and three states. This study represents the first binationally focused application of SPAtially Referenced Regressions on Watershed attributes (SPARROW) models to estimate loads and sources of TP and TN by jurisdiction and basin at multiple spatial scales. Major hurdles overcome to develop these models included: (1) harmonization of geospatial data sets, particularly construction of a contiguous stream network; and (2) use of novel calibration steps to accommodate limitations in spatial variability across the model extent and in the number of calibration sites. Using nutrient inputs for a 2002 base year, a RARB TP SPARROW model was calibrated that included inputs from agriculture, forests and wetlands, wastewater treatment plants (WWTPs) and stream channels, and a TN model was calibrated that included inputs from agriculture, WWTPs and atmospheric deposition. At the RARB outlet, downstream from Winnipeg, Manitoba, the majority of the delivered TP and TN came from the Red River Basin (90%), followed by the Upper Assiniboine River and Souris River basins. Agriculture was the single most important TP and TN source for each major basin, province and state. In general, stream channels (historically deposited nutrients and from bank erosion) were the second most important source of TP. Performance metrics for the RARB SPARROW model are similarly robust compared to other, larger US SPARROW models making it a potentially useful tool to address questions of where nutrients originate and their relative contributions to loads delivered to Lake Winnipeg.

Integrating sentinel watershed-systems into the monitoring and assessment of Minnesota's (USA) waters quality.

PubMed

Magner, J A; Brooks, K N

2008-03-01

Section 303(d) of the Clean Water Act requires States and Tribes to list waters not meeting water quality standards. A total maximum daily load must be prepared for waters identified as impaired with respect to water quality standards. Historically, the management of pollution in Minnesota has been focused on point-source regulation. Regulatory effort in Minnesota has improved water quality over the last three decades. Non-point source pollution has become the largest driver of conventional 303(d) listings in the 21st century. Conventional pollutants, i.e., organic, sediment and nutrient imbalances can be identified with poor land use management practices. However, the cause and effect relationship can be elusive because of natural watershed-system influences that vary with scale. Elucidation is complex because the current water quality standards in Minnesota were designed to work best with water quality permits to control point sources of pollution. This paper presents a sentinel watershed-systems approach (SWSA) to the monitoring and assessment of Minnesota waterbodies. SWSA integrates physical, chemical, and biological data over space and time using advanced technologies at selected small watersheds across Minnesota to potentially improve understanding of natural and anthropogenic watershed processes and the management of point and non-point sources of pollution. Long-term, state-of-the-art monitoring and assessment is needed to advance and improve water quality standards. Advanced water quality or ecologically-based standards that integrate physical, chemical, and biological numeric criteria offer the potential to better understand, manage, protect, and restore Minnesota's waterbodies.

High-frequency monitoring reveals nutrient sources and transport processes in an agriculture-dominated lowland water system

NASA Astrophysics Data System (ADS)

van der Grift, Bas; Broers, Hans Peter; Berendrecht, Wilbert; Rozemeijer, Joachim; Osté, Leonard; Griffioen, Jasper

2016-05-01

Many agriculture-dominated lowland water systems worldwide suffer from eutrophication caused by high nutrient loads. Insight in the hydrochemical functioning of embanked polder catchments is highly relevant for improving the water quality in such areas or for reducing export loads to downstream water bodies. This paper introduces new insights in nutrient sources and transport processes in a polder in the Netherlands situated below sea level using high-frequency monitoring technology at the outlet, where the water is pumped into a higher situated lake, combined with a low-frequency water quality monitoring programme at six locations within the drainage area. Seasonal trends and short-scale temporal dynamics in concentrations indicated that the NO3 concentration at the pumping station originated from N loss from agricultural lands. The NO3 loads appear as losses via tube drains after intensive rainfall events during the winter months due to preferential flow through the cracked clay soil. Transfer function-noise modelling of hourly NO3 concentrations reveals that a large part of the dynamics in NO3 concentrations during the winter months can be related to rainfall. The total phosphorus (TP) concentration and turbidity almost doubled during operation of the pumping station, which points to resuspension of particulate P from channel bed sediments induced by changes in water flow due to pumping. Rainfall events that caused peaks in NO3 concentrations did not results in TP concentration peaks. The rainfall induced and NO3 enriched quick interflow, may also be enriched in TP but retention of TP due to sedimentation of particulate P then results in the absence of rainfall induced TP concentration peaks. Increased TP concentrations associated with run-off events is only observed during a rainfall event at the end of a freeze-thaw cycle. All these observations suggest that the P retention potential of polder water systems is primarily due to the artificial pumping regime that buffers high flows. As the TP concentration is affected by operation of the pumping station, timing of sampling relative to the operating hours of the pumping station should be accounted for when calculating P export loads, determining trends in water quality, or when judging water quality status of polder water systems.

Solving Nutrient Loading in the Great Lakes: An Integrative, Interdisciplinary and Ambidextrous Approach

NASA Astrophysics Data System (ADS)

Borrello, M. C.; Keeton, T.; Foley, T.; Frost, A.; Green, N.; Isler, J.

2014-12-01

Environmental impacts from industrialized agriculture have been studied extensively over the past two decades. Degradation of surface water occurs, primarily as a result of nutrient loading, causing algal blooms in streams and lakes. Discovery of the toxin microcystin in Lake Erie, a drinking water source for some municipalities, has been associated with agricultural runoff and created a new awareness in the general public. This study used data gathered over ten years by local residents, high school students and undergraduates on surface water around the Lower Peninsula of Michigan to test a simple correlation of nutrients (soluble reactive phosphorus and nitrogen ammonia) along with the presence of specific antibiotics and antibiotic resistance to identify dominant sources of nutrient loading in the Lake Huron Watershed. Data gathering came from multiple sources and were processed by faculty and students at an undergraduate, liberal arts institution. College students from various disciplines worked with community members and municipalities in an effort to describe the problem. Students proposed solutions which by-passed relatively inactive regulatory agencies to create an integrative, interactive resolution that involved a surprisingly wide extent of the community. Addressing cultural norms beginning with those most affected by a degraded environment has reaped some success in changing behavior and moving towards a sustainable solution. The research conducted and supervised by undergraduate students has significance in the broader, professional area of geochemistry, environmental health and sustainable agriculture. That fact plays an important role in how the students see themselves in the process and what motivated them to: 1. Choose to participate in the research in the first place, 2. Reach out to the broader community (scientific and regional) to carry out their research and 3. Pursue solutions beyond the classroom and summer research experience.

Increased nutrient concentrations in Lake Erie tributaries influenced by greenhouse agriculture.

PubMed

Maguire, Timothy J; Wellen, Christopher; Stammler, Katie L; Mundle, Scott O C

2018-08-15

Greenhouse production of vegetables is a growing global trade. While greenhouses are typically captured under regulations aimed at farmland, they may also function as a point source of effluent. In this study, the cumulative impacts greenhouse effluents have on riverine macronutrient and trace metal concentrations were examined. Water samples were collected Bi-weekly for five years from 14 rivers in agriculturally dominated watersheds in southwestern Ontario. Nine of the watersheds contained greenhouses with their boundaries. Greenhouse influenced rivers had significantly higher concentrations of macronutrients (nitrogen, phosphorus, and potassium) and trace metals (copper, molybdenum, and zinc). Concentrations within greenhouse influenced rivers appeared to decrease over the 5-year study while concentrations within non-greenhouse influenced river remained constant. The different temporal pattern between river types was attributed to increased precipitation during the study period. Increases in precipitation diluted concentrations in greenhouse influenced rivers; however, non-influenced river runoff proportionally increased nutrient mobility and flow, stabilizing the observed concentrations of non-point sources. Understanding the dynamic nature of environmental releases of point and non-point sources of nutrients and trace metals in mixed agricultural systems using riverine water chemistry is complicated by changes in climatic conditions, highlighting the need for long-term monitoring of nutrients, river flows and weather data in assessing these agricultural sectors. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Nutrient patterns and their food sources in an International Study Setting: report from the EPIC study.

PubMed

Moskal, Aurelie; Pisa, Pedro T; Ferrari, Pietro; Byrnes, Graham; Freisling, Heinz; Boutron-Ruault, Marie-Christine; Cadeau, Claire; Nailler, Laura; Wendt, Andrea; Kühn, Tilman; Boeing, Heiner; Buijsse, Brian; Tjønneland, Anne; Halkjær, Jytte; Dahm, Christina C; Chiuve, Stephanie E; Quirós, Jose R; Buckland, Genevieve; Molina-Montes, Esther; Amiano, Pilar; Huerta Castaño, José M; Gurrea, Aurelio Barricarte; Khaw, Kay-Tee; Lentjes, Marleen A; Key, Timothy J; Romaguera, Dora; Vergnaud, Anne-Claire; Trichopoulou, Antonia; Bamia, Christina; Orfanos, Philippos; Palli, Domenico; Pala, Valeria; Tumino, Rosario; Sacerdote, Carlotta; de Magistris, Maria Santucci; Bueno-de-Mesquita, H Bas; Ocké, Marga C; Beulens, Joline W J; Ericson, Ulrika; Drake, Isabel; Nilsson, Lena M; Winkvist, Anna; Weiderpass, Elisabete; Hjartåker, Anette; Riboli, Elio; Slimani, Nadia

2014-01-01

Compared to food patterns, nutrient patterns have been rarely used particularly at international level. We studied, in the context of a multi-center study with heterogeneous data, the methodological challenges regarding pattern analyses. We identified nutrient patterns from food frequency questionnaires (FFQ) in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study and used 24-hour dietary recall (24-HDR) data to validate and describe the nutrient patterns and their related food sources. Associations between lifestyle factors and the nutrient patterns were also examined. Principal component analysis (PCA) was applied on 23 nutrients derived from country-specific FFQ combining data from all EPIC centers (N = 477,312). Harmonized 24-HDRs available for a representative sample of the EPIC populations (N = 34,436) provided accurate mean group estimates of nutrients and foods by quintiles of pattern scores, presented graphically. An overall PCA combining all data captured a good proportion of the variance explained in each EPIC center. Four nutrient patterns were identified explaining 67% of the total variance: Principle component (PC) 1 was characterized by a high contribution of nutrients from plant food sources and a low contribution of nutrients from animal food sources; PC2 by a high contribution of micro-nutrients and proteins; PC3 was characterized by polyunsaturated fatty acids and vitamin D; PC4 was characterized by calcium, proteins, riboflavin, and phosphorus. The nutrients with high loadings on a particular pattern as derived from country-specific FFQ also showed high deviations in their mean EPIC intakes by quintiles of pattern scores when estimated from 24-HDR. Center and energy intake explained most of the variability in pattern scores. The use of 24-HDR enabled internal validation and facilitated the interpretation of the nutrient patterns derived from FFQs in term of food sources. These outcomes open research opportunities and perspectives of using nutrient patterns in future studies particularly at international level.

Estimation of particulate nutrient load using turbidity meter.

PubMed

Yamamoto, K; Suetsugi, T

2006-01-01

The "Nutrient Load Hysteresis Coefficient" was proposed to evaluate the hysteresis of the nutrient loads to flow rate quantitatively. This could classify the runoff patterns of nutrient load into 15 patterns. Linear relationships between the turbidity and the concentrations of particulate nutrients were observed. It was clarified that the linearity was caused by the influence of the particle size on turbidity output and accumulation of nutrients on smaller particles (diameter < 23 microm). The L-Q-Turb method, which is a new method for the estimation of runoff loads of nutrients using a regression curve between the turbidity and the concentrations of particulate nutrients, was developed. This method could raise the precision of the estimation of nutrient loads even if they had strong hysteresis to flow rate. For example, as for the runoff load of total phosphorus load on flood events in a total of eight cases, the averaged error of estimation of total phosphorus load by the L-Q-Turb method was 11%, whereas the averaged estimation error by the regression curve between flow rate and nutrient load was 28%.

2020s scenario analysis of nutrient load in the Mekong River Basin using a distributed hydrological model.

PubMed

Yoshimura, Chihiro; Zhou, Maichun; Kiem, Anthony S; Fukami, Kazuhiko; Prasantha, Hapuarachchi H A; Ishidaira, Hiroshi; Takeuchi, Kuniyoshi

2009-10-01

A distributed hydrological model, YHyM, was integrated with the export coefficient concept and applied to simulate the nutrient load in the Mekong River Basin. In the validation period (1992-1999), Nash-Sutcliffe efficiency was 76.4% for discharge, 65.9% for total nitrogen, and 45.3% for total phosphorus at Khong Chiam. Using the model, scenario analysis was then performed for the 2020s taking into account major anthropogenic factors: climate change, population, land cover, fertilizer use, and industrial waste water. The results show that the load at Kompong Cham in 2020s is 6.3 x 10(4)tN a(-1) (+13.0% compared to 1990s) and 4.3 x 10(3)tP a(-1) (+24.7%). Overall, the noticeable nutrient sources are cropland in the middle region and urban load in the lower region. The installation of waste water treatment plants in urban areas possibly cut 60.6%N and 19.9%P of the estimated increase in the case without any treatment.

A spatial and seasonal assessment of river water chemistry across North West England.

PubMed

Rothwell, J J; Dise, N B; Taylor, K G; Allott, T E H; Scholefield, P; Davies, H; Neal, C

2010-01-15

This paper presents information on the spatial and seasonal patterns of river water chemistry at approximately 800 sites in North West England based on data from the Environment Agency regional monitoring programme. Within a GIS framework, the linkages between average water chemistry (pH, sulphate, base cations, nutrients and metals) catchment characteristics (topography, land cover, soil hydrology, base flow index and geology), rainfall, deposition chemistry and geo-spatial information on discharge consents (point sources) are examined. Water quality maps reveal that there is a clear distinction between the uplands and lowlands. Upland waters are acidic and have low concentrations of base cations, explained by background geological sources and land cover. Localised high concentrations of metals occur in areas of the Cumbrian Fells which are subjected to mining effluent inputs. Nutrient concentrations are low in the uplands with the exception sites receiving effluent inputs from rural point sources. In the lowlands, both past and present human activities have a major impact on river water chemistry, especially in the urban and industrial heartlands of Greater Manchester, south Lancashire and Merseyside. Over 40% of the sites have average orthophosphate concentrations >0.1mg-Pl(-1). Results suggest that the dominant control on orthophosphate concentrations is point source contributions from sewage effluent inputs. Diffuse agricultural sources are also important, although this influence is masked by the impact of point sources. Average nitrate concentrations are linked to the coverage of arable land, although sewage effluent inputs have a significant effect on nitrate concentrations. Metal concentrations in the lowlands are linked to diffuse and point sources. The study demonstrates that point sources, as well as diffuse sources, need to be considered when targeting measures for the effective reduction in river nutrient concentrations. This issue is clearly important with regards to the European Union Water Framework Directive, eutrophication and river water quality. Copyright 2009 Elsevier B.V. All rights reserved.

Evaluating watershed protection programs in New York City's Cannonsville Reservoir source watershed using SWAT-HS

NASA Astrophysics Data System (ADS)

Hoang, L.; Mukundan, R.; Moore, K. E.; Owens, E. M.; Steenhuis, T. S.

2017-12-01

New York City (NYC)'s reservoirs supply over one billion gallons of drinking water each day to over nine million consumers in NYC and upstate communities. The City has invested more than $1.5 billion in watershed protection programs to maintain a waiver from filtration for the Catskill and Delaware Systems. In the last 25 years, the NYC Department of Environmental Protection (NYCDEP) has implemented programs in cooperation with upstate communities that include nutrient management, crop rotations, improvement of barnyards and manure storage, implementing tertiary treatment for Phosphorus (P) in wastewater treatment plants, and replacing failed septic systems in an effort to reduce P loads to water supply reservoirs. There have been several modeling studies evaluating the effect of agricultural Best Management Practices (BMPs) on P control in the Cannonsville watershed in the Delaware System. Although these studies showed that BMPs would reduce dissolved P losses, they were limited to farm-scale or watershed-scale estimates of reduction factors without consideration of the dynamic nature of overland flow and P losses from variable source areas. Recently, we developed the process-based SWAT-Hillslope (SWAT-HS) model, a modified version of the Soil and Water Assessment Tool (SWAT) that can realistically predict variable source runoff processes. The objective of this study is to use the SWAT-HS model to evaluate watershed protection programs addressing both point and non-point sources of P. SWAT-HS predicts streamflow very well for the Cannonsville watershed with a daily Nash Sutcliffe Efficiency (NSE) of 0.85 at the watershed outlet and NSE values ranging from 0.56 - 0.82 at five other locations within the watershed. Based on good hydrological prediction, we applied the model to predict P loads using detailed P inputs that change over time due to the implementation of watershed protection programs. Results from P model predictions provide improved projections of P loads and form a basis for evaluating the cumulative and individual effects of watershed protection programs.

Impacts of elevated terrestrial nutrient loads and temperature on pelagic food-web efficiency and fish production.

PubMed

Lefébure, R; Degerman, R; Andersson, A; Larsson, S; Eriksson, L-O; Båmstedt, U; Byström, P

2013-05-01

Both temperature and terrestrial organic matter have strong impacts on aquatic food-web dynamics and production. Temperature affects vital rates of all organisms, and terrestrial organic matter can act both as an energy source for lower trophic levels, while simultaneously reducing light availability for autotrophic production. As climate change predictions for the Baltic Sea and elsewhere suggest increases in both terrestrial matter runoff and increases in temperature, we studied the effects on pelagic food-web dynamics and food-web efficiency in a plausible future scenario with respect to these abiotic variables in a large-scale mesocosm experiment. Total basal (phytoplankton plus bacterial) production was slightly reduced when only increasing temperatures, but was otherwise similar across all other treatments. Separate increases in nutrient loads and temperature decreased the ratio of autotrophic:heterotrophic production, but the combined treatment of elevated temperature and terrestrial nutrient loads increased both fish production and food-web efficiency. CDOM: Chl a ratios strongly indicated that terrestrial and not autotrophic carbon was the main energy source in these food webs and our results also showed that zooplankton biomass was positively correlated with increased bacterial production. Concomitantly, biomass of the dominant calanoid copepod Acartia sp. increased as an effect of increased temperature. As the combined effects of increased temperature and terrestrial organic nutrient loads were required to increase zooplankton abundance and fish production, conclusions about effects of climate change on food-web dynamics and fish production must be based on realistic combinations of several abiotic factors. Moreover, our results question established notions on the net inefficiency of heterotrophic carbon transfer to the top of the food web. © 2013 Blackwell Publishing Ltd.

Repeat synoptic sampling reveals drivers of change in carbon and nutrient chemistry of Arctic catchments

NASA Astrophysics Data System (ADS)

Zarnetske, J. P.; Abbott, B. W.; Bowden, W. B.; Iannucci, F.; Griffin, N.; Parker, S.; Pinay, G.; Aanderud, Z.

2017-12-01

Dissolved organic carbon (DOC), nutrients, and other solute concentrations are increasing in rivers across the Arctic. Two hypotheses have been proposed to explain these trends: 1. distributed, top-down permafrost degradation, and 2. discrete, point-source delivery of DOC and nutrients from permafrost collapse features (thermokarst). While long-term monitoring at a single station cannot discriminate between these mechanisms, synoptic sampling of multiple points in the stream network could reveal the spatial structure of solute sources. In this context, we sampled carbon and nutrient chemistry three times over two years in 119 subcatchments of three distinct Arctic catchments (North Slope, Alaska). Subcatchments ranged from 0.1 to 80 km2, and included three distinct types of Arctic landscapes - mountainous, tundra, and glacial-lake catchments. We quantified the stability of spatial patterns in synoptic water chemistry and analyzed high-frequency time series from the catchment outlets across the thaw season to identify source areas for DOC, nutrients, and major ions. We found that variance in solute concentrations between subcatchments collapsed at spatial scales between 1 to 20 km2, indicating a continuum of diffuse- and point-source dynamics, depending on solute and catchment characteristics (e.g. reactivity, topography, vegetation, surficial geology). Spatially-distributed mass balance revealed conservative transport of DOC and nitrogen, and indicates there may be strong in-stream retention of phosphorus, providing a network-scale confirmation of previous reach-scale studies in these Arctic catchments. Overall, we present new approaches to analyzing synoptic data for change detection and quantification of ecohydrological mechanisms in ecosystems in the Arctic and beyond.

Trees and Streets as Drivers of Urban Stormwater Nutrient Pollution.

PubMed

Janke, Benjamin D; Finlay, Jacques C; Hobbie, Sarah E

2017-09-05

Expansion of tree cover is a major management goal in cities because of the substantial benefits provided to people, and potentially to water quality through reduction of stormwater volume by interception. However, few studies have addressed the full range of potential impacts of trees on urban runoff, which includes deposition of nutrient-rich leaf litter onto streets connected to storm drains. We analyzed the influence of trees on stormwater nitrogen and phosphorus export across 19 urban watersheds in Minneapolis-St. Paul, MN, U.S.A., and at the scale of individual streets within one residential watershed. Stormwater nutrient concentrations were highly variable across watersheds and strongly related to tree canopy over streets, especially for phosphorus. Stormwater nutrient loads were primarily related to road density, the dominant control over runoff volume. Street canopy exerted opposing effects on loading, where elevated nutrient concentrations from trees near roads outweighed the weak influence of trees on runoff reduction. These results demonstrate that vegetation near streets contributes substantially to stormwater nutrient pollution, and therefore to eutrophication of urban surface waters. Urban landscape design and management that account for trees as nutrient pollution sources could improve water quality outcomes, while allowing cities to enjoy the myriad benefits of urban forests.

Quantitative Assessment of Agricultural Runoff and Soil Erosion Using Mathematical Modeling: Applications in the Mediterranean Region

NASA Astrophysics Data System (ADS)

Arhonditsis, G.; Giourga, C.; Loumou, A.; Koulouri, M.

2002-09-01

Three mathematical models, the runoff curve number equation, the universal soil loss equation, and the mass response functions, were evaluated for predicting nonpoint source nutrient loading from agricultural watersheds of the Mediterranean region. These methodologies were applied to a catchment, the gulf of Gera Basin, that is a typical terrestrial ecosystem of the islands of the Aegean archipelago. The calibration of the model parameters was based on data from experimental plots from which edge-of-field losses of sediment, water runoff, and nutrients were measured. Special emphasis was given to the transport of dissolved and solid-phase nutrients from their sources in the farmers' fields to the outlet of the watershed in order to estimate respective attenuation rates. It was found that nonpoint nutrient loading due to surface losses was high during winter, the contribution being between 50% and 80% of the total annual nutrient losses from the terrestrial ecosystem. The good fit between simulated and experimental data supports the view that these modeling procedures should be considered as reliable and effective methodological tools in Mediterranean areas for evaluating potential control measures, such as management practices for soil and water conservation and changes in land uses, aimed at diminishing soil loss and nutrient delivery to surface waters. Furthermore, the modifications of the general mathematical formulations and the experimental values of the model parameters provided by the study can be used in further application of these methodologies in watersheds with similar characteristics.

Nutrient Loads Flowing into Coastal Waters from the Main Rivers of China (2006–2012)

PubMed Central

Tong, Yindong; Zhao, Yue; Zhen, Gengchong; Chi, Jie; Liu, Xianhua; Lu, Yiren; Wang, Xuejun; Yao, Ruihua; Chen, Junyue; Zhang, Wei

2015-01-01

Based on monthly monitoring data of unfiltered water, the nutrient discharges of the eight main rivers flowing into the coastal waters of China were calculated from 2006 to 2012. In 2012, the total load of NH3-N (calculated in nitrogen), total nitrogen (TN, calculated in nitrogen) and total phosphorus (TP, calculated in phosphorus) was 5.1 × 105, 3.1 × 106 and 2.8 × 105 tons, respectively, while in 2006, the nutrient load was 7.4 × 105, 2.2 × 106 and 1.6 × 105 tons, respectively. The nutrient loading from the eight major rivers into the coastal waters peaked in summer and autumn, probably due to the large water discharge in the wet season. The Yangtze River was the largest riverine nutrient source for the coastal waters, contributing 48% of the NH3-N discharges, 66% of the TN discharges and 84% of the TP discharges of the eight major rivers in 2012. The East China Sea received the majority of the nutrient discharges, i.e. 50% of NH3-N (2.7 × 105 tons), 70% of TN (2.2 × 106 tons) and 87% of TP (2.5 × 105 tons) in 2012. The riverine discharge of TN into the Yellow Sea and Bohai Sea was lower than that from the direct atmospheric deposition, while for the East China Sea, the riverine TN input was larger. PMID:26582206

Nutrient Loads Flowing into Coastal Waters from the Main Rivers of China (2006-2012).

PubMed

Tong, Yindong; Zhao, Yue; Zhen, Gengchong; Chi, Jie; Liu, Xianhua; Lu, Yiren; Wang, Xuejun; Yao, Ruihua; Chen, Junyue; Zhang, Wei

2015-11-19

Based on monthly monitoring data of unfiltered water, the nutrient discharges of the eight main rivers flowing into the coastal waters of China were calculated from 2006 to 2012. In 2012, the total load of NH3-N (calculated in nitrogen), total nitrogen (TN, calculated in nitrogen) and total phosphorus (TP, calculated in phosphorus) was 5.1 × 10(5), 3.1 × 10(6) and 2.8 × 10(5) tons, respectively, while in 2006, the nutrient load was 7.4 × 10(5), 2.2 × 10(6) and 1.6 × 10(5) tons, respectively. The nutrient loading from the eight major rivers into the coastal waters peaked in summer and autumn, probably due to the large water discharge in the wet season. The Yangtze River was the largest riverine nutrient source for the coastal waters, contributing 48% of the NH3-N discharges, 66% of the TN discharges and 84% of the TP discharges of the eight major rivers in 2012. The East China Sea received the majority of the nutrient discharges, i.e. 50% of NH3-N (2.7 × 10(5) tons), 70% of TN (2.2 × 10(6) tons) and 87% of TP (2.5 × 10(5) tons) in 2012. The riverine discharge of TN into the Yellow Sea and Bohai Sea was lower than that from the direct atmospheric deposition, while for the East China Sea, the riverine TN input was larger.

What is the role of fresh groundwater and recirculated seawater in conveying nutrients to the coastal ocean?

USGS Publications Warehouse

Weinstein, Y.; Yechieli, Y.; Shalem, Y.; Burnett, W.C.; Swarzenski, P.W.; Herut, B.

2011-01-01

Submarine groundwater discharge (SGD) is a major process operating at the land-sea interface. Quantifying the SGD nutrient loads and the marine/terrestrial controls of this transport is of high importance, especially in oligotrophic seas such as the eastern Mediterranean. The fluxes of nutrients in groundwater discharging from the seafloor at Dor Bay (southeastern Mediterranean) were studied in detail using seepage meters. Our main finding is that the terrestrial, fresh groundwater is the main conveyor of DIN and silica to the coastal water, with loads of 500 and 560 mol/yr, respectively, per 1 m shoreline. Conversely, recirculated seawater is nutrient-poor, and its role is mainly as a dilution agent. The nutrient loads regenerated in the subterranean estuary (sub-bay sediment) are relatively small, consisting mostly of ammonium (24 mol/yr). On the other hand, the subterranean estuary at Dor Bay sequesters as much as 100 mol N/yr per 1 m shoreline, mainly via denitrification processes. These, and observations from other SGD sites, imply that the subterranean estuary at some coastal systems may function more as a sink for nitrogen than a source. This further questions the extent of nutrient contributions to the coastal water by some subterranean estuaries and warrants systematic evaluation of this process in various hydrological and marine trophic conditions. ?? 2011 American Chemical Society.

Application of Water Quality Model of Jordan River to Evaluate Climate Change Effects on Eutrophication

NASA Astrophysics Data System (ADS)

Van Grouw, B.

2016-12-01

The Jordan River is a 51 mile long freshwater stream in Utah that provides drinking water to more than 50% of Utah's population. The various point and nonpoint sources introduce an excess of nutrients into the river. This excess induces eutrophication that results in an inhabitable environment for aquatic life is expected to be exacerbated due to climate change. Adaptive measures must be evaluated based on predictions of climate variation impacts on eutrophication and ecosystem processes in the Jordan River. A Water Quality Assessment Simulation Program (WASP) model was created to analyze the data results acquired from a Total Maximum Daily Load (TMDL) study conducted on the Jordan River. Eutrophication is modeled based on levels of phosphates and nitrates from point and nonpoint sources, temperature, and solar radiation. It will simulate the growth of phytoplankton and periphyton in the river. This model will be applied to assess how water quality in the Jordan River is affected by variations in timing and intensity of spring snowmelt and runoff during drought in the valley and the resulting effects on eutrophication in the river.

Concentrations, and estimated loads and yields of nutrients and suspended sediment in the Little River basin, Kentucky, 2003-04

USGS Publications Warehouse

Crain, Angela S.

2006-01-01

Nutrients, primarily nitrogen and phosphorus compounds, naturally occur but also are applied to land in the form of commercial fertilizers and livestock waste to enhance plant growth. Concentrations, estimated loads and yields, and sources of nitrite plus nitrate, total phosphorus, and orthophosphate were evaluated in streams of the Little River Basin to assist the Commonwealth of Kentucky in developing 'total maximum daily loads' (TMDLs) for streams in the basin. The Little River Basin encompasses about 600 square miles in Christian and Trigg Counties, and a portion of Caldwell County in western Kentucky. Water samples were collected in streams in the Little River Basin during 2003-04 as part of a study conducted in cooperation with the Kentucky Department of Agriculture. A total of 92 water samples were collected at four fixed-network sites from March through November 2003 and from February through November 2004. An additional 20 samples were collected at five synoptic-network sites during the same period. Median concentrations of nitrogen, phosphorus, and suspended sediment varied spatially and seasonally. Concentrations of nitrogen were higher in the spring (March-May) after fertilizer application and runoff. The highest concentration of nitrite plus nitrate-5.7 milligrams per liter (mg/L)-was detected at the South Fork Little River site. The Sinking Fork near Cadiz site had the highest median concentration of nitrite plus nitrate (4.6 mg/L). The North Fork Little River site and the Little River near Cadiz site had higher concentrations of orthophosphate in the fall and lower concentrations in the spring. Concentrations of orthophosphate remained high during the summer (June-August) at the North Fork Little River site possibly because of the contribution of wastewater effluent to streamflow. Fifty-eight percent of the concentrations of total phosphorus at the nine sites exceeded the U.S. Environmental Protection Agency recommended maximum concentration limit of 0.1 mg/L. Concentrations of suspended sediment were highest in the spring during runoff and lowest in the fall. The highest concentration of suspended sediment (1,020 mg/L) was observed at the Sinking Fork near Cadiz site. The median concentration of suspended sediment for all sites sampled was 12 mg/L. A nonparameteric statistical test (Wilcoxson rank-sum) showed that the median concentrations of suspended sediment were not different among any of the fixed-network sites. The Little River near Cadiz site contributed larger estimated mean annual loads of nitrite plus nitrate (2,500,000 pounds per year (lb/yr)) and total phosphorus (160,000 lb/yr) than the other three fixed-network sites. Of the two main upstream tributaries from the Little River near Cadiz site, the North Fork Little River was the greatest contributor of total phosphorus to the study area with an estimated mean annual load of 107,000 lb/yr or about 64 percent of the total estimated mean annual load at the Little River near Cadiz site. The other main upstream tributary, South Fork Little River, had an estimated mean annual load of total phosphorus that was about 20 percent of the mean annual load at the Little River near Cadiz site. Estimated loads of suspended sediment were largest at the Little River near Cadiz site, where the estimated mean annual load for 2003-04 was about 84,000,000 lb/yr. The North Fork Little River contributed an estimated 36 percent of the mean annual load of suspended sediment at the Little River near Cadiz site, while the South Fork Little River contributed an estimated 18 percent of the mean annual load at the Little River near Cadiz site. The North Fork Little River site had the largest estimated mean annual yield of total phosphorus (1,600 pounds per year per square mile (lb/yr/mi2)) and orthophosphate (1,100 lb/yr/mi2). A principal source of phosphorus for the North Fork Little River is discharge from wastewater-treatment facilities. The largest estimated mean annual yield of nitrite plus nitrate was observed at the South Fork Little River site. The North Fork Little River site had the largest estimated mean annual yield of suspended sediment (450,000 lb/yr/mi2). Inputs of nitrogen and phosphorus to streams from point and nonpoint sources were estimated for the Little River Basin. Commercial fertilizer and livestock-waste applications on row crops are a principal source of nutrients for most of the Little River Basin. Sources of nutrients in the urban areas of the basin mainly are from effluent discharge from wastewater-treatment facilities and fertilizer applications to lawns and golf courses.

Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate-Scale Hydrodynamic Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Zhaoqing; Khangaonkar, Tarang; Labiosa, Rochelle G.

2010-11-30

The Washington State Department of Ecology contracted with Pacific Northwest National Laboratory to develop an intermediate-scale hydrodynamic and water quality model to study dissolved oxygen and nutrient dynamics in Puget Sound and to help define potential Puget Sound-wide nutrient management strategies and decisions. Specifically, the project is expected to help determine 1) if current and potential future nitrogen loadings from point and non-point sources are significantly impairing water quality at a large scale and 2) what level of nutrient reductions are necessary to reduce or dominate human impacts to dissolved oxygen levels in the sensitive areas. In this study, anmore » intermediate-scale hydrodynamic model of Puget Sound was developed to simulate the hydrodynamics of Puget Sound and the Northwest Straits for the year 2006. The model was constructed using the unstructured Finite Volume Coastal Ocean Model. The overall model grid resolution within Puget Sound in its present configuration is about 880 m. The model was driven by tides, river inflows, and meteorological forcing (wind and net heat flux) and simulated tidal circulations, temperature, and salinity distributions in Puget Sound. The model was validated against observed data of water surface elevation, velocity, temperature, and salinity at various stations within the study domain. Model validation indicated that the model simulates tidal elevations and currents in Puget Sound well and reproduces the general patterns of the temperature and salinity distributions.« less

Nutrient mass balance and trends, Mobile River Basin, Alabama, Georgia, and Mississippi

USGS Publications Warehouse

Harned, D.A.; Atkins, J.B.; Harvill, J.S.

2004-01-01

A nutrient mass balance - accounting for nutrient inputs from atmospheric deposition, fertilizer, crop nitrogen fixation, and point source effluents; and nutrient outputs, including crop harvest and storage - was calculated for 18 subbasins in the Mobile River Basin, and trends (1970 to 1997) were evaluated as part of the U.S. Geological Survey National Water Quality Assessment (NAWQA) Program. Agricultural nonpoint nitrogen and phosphorus sources and urban nonpoint nitrogen sources are the most important factors associated with nutrients in this system. More than 30 percent of nitrogen yield in two basins and phosphorus yield in eight basins can be attributed to urban point source nutrient inputs. The total nitrogen yield (1.3 tons per square mile per year) for the Tombigbee River, which drains a greater percentage of agricultural (row crop) land use, was larger than the total nitrogen yield (0.99 tons per square mile per year) for the Alabama River. Decreasing trends of total nitrogen concentrations in the Tombigbee and Alabama Rivers indicate that a reduction occurred from 1975 to 1997 in the nitrogen contributions to Mobile Bay from the Mobile River. Nitrogen concentrations also decreased (1980 to 1995) in the Black Warrior River, one of the major tributaries to the Tombigbee River. Total phosphorus concentrations increased from 1970 to 1996 at three urban influenced sites on the Etowah River in Georgia. Multiple regression analysis indicates a distinct association between water quality in the streams of the Mobile River drainage basin and agricultural activities in the basin.

Monitor-based evaluation of pollutant load from urban stormwater runoff in Beijing.

PubMed

Liu, Y; Che, W; Li, J

2005-01-01

As a major pollutant source to urban receiving waters, the non-point source pollution from urban runoff needs to be well studied and effectively controlled. Based on monitoring data from urban runoff pollutant sources, this article describes a systematic estimation of total pollutant loads from the urban areas of Beijing. A numerical model was developed to quantify main pollutant loads of urban runoff in Beijing. A sub-procedure is involved in this method, in which the flush process influences both the quantity and quality of stormwater runoff. A statistics-based method was applied in computing the annual pollutant load as an output of the runoff. The proportions of pollutant from point-source and non-point sources were compared. This provides a scientific basis for proper environmental input assessment of urban stormwater pollution to receiving waters, improvement of infrastructure performance, implementation of urban stormwater management, and utilization of stormwater.

Development of a time-stepping sediment budget model for assessing land use impacts in large river basins.

PubMed

Wilkinson, S N; Dougall, C; Kinsey-Henderson, A E; Searle, R D; Ellis, R J; Bartley, R

2014-01-15

The use of river basin modelling to guide mitigation of non-point source pollution of wetlands, estuaries and coastal waters has become widespread. To assess and simulate the impacts of alternate land use or climate scenarios on river washload requires modelling techniques that represent sediment sources and transport at the time scales of system response. Building on the mean-annual SedNet model, we propose a new D-SedNet model which constructs daily budgets of fine sediment sources, transport and deposition for each link in a river network. Erosion rates (hillslope, gully and streambank erosion) and fine sediment sinks (floodplains and reservoirs) are disaggregated from mean annual rates based on daily rainfall and runoff. The model is evaluated in the Burdekin basin in tropical Australia, where policy targets have been set for reducing sediment and nutrient loads to the Great Barrier Reef (GBR) lagoon from grazing and cropping land. D-SedNet predicted annual loads with similar performance to that of a sediment rating curve calibrated to monitored suspended sediment concentrations. Relative to a 22-year reference load time series at the basin outlet derived from a dynamic general additive model based on monitoring data, D-SedNet had a median absolute error of 68% compared with 112% for the rating curve. RMS error was slightly higher for D-SedNet than for the rating curve due to large relative errors on small loads in several drought years. This accuracy is similar to existing agricultural system models used in arable or humid environments. Predicted river loads were sensitive to ground vegetation cover. We conclude that the river network sediment budget model provides some capacity for predicting load time-series independent of monitoring data in ungauged basins, and for evaluating the impact of land management on river sediment load time-series, which is challenging across large regions in data-poor environments. © 2013. Published by Elsevier B.V. All rights reserved.

Nutrient dynamics in five off-stream reservoirs in the lower South Platte River basin, March-September 1995

USGS Publications Warehouse

Sprague, Lori A.

2002-01-01

In 1995, the U.S. Geological Survey conducted a study to characterize nutrient concentrations in five off-stream reservoirs in the lower South Platte River Basin?Riverside, Jackson, Prewitt, North Sterling, and Julesburg. These reservoirs are critical sources of irrigation water for agricultural areas, and several also are used for fishing, boating, swimming, hunting, and camping. Data collected for this study include depth profiles of water temperature, dissolved oxygen, pH, and specific conductance; nutrient species concentrations in the water column, bottom sediment, and inflow and outflow canals; and chlorophyll-a concentrations in the water column. Data were collected during the irrigation season from March through September 1995 at five sites each in Riverside, Jackson, Prewitt, and Julesburg Reservoirs and at six sites in North Sterling Reservoir. The five reservoirs studied are located in similar geographic, climatic, and land-use areas and, as a result, have a number of similarities in their internal nutrient dynamics. Nitrogen concentrations in the reservoirs were highest in March and decreased through September as a result of dilution from river inflows and biological activity. From March through June, decreases in nitrogen concentrations in the river and biological activity contributed to decreases in reservoir concentrations. From July through September, inflows from the river were cut off, and biological activity in the reservoirs led to further decreases in nitrate concentrations, which fell to near or below detectable levels. Phosphorus concentrations in the reservoirs did not show the same consistent decrease from March through September. Phosphorus likely was recycled continuously back to algae during the study period through processes such as excretion from fish, decay of aquatic plants and animals, and release of orthophosphate from bottom sediment during periods of low oxygen. With the exception of phosphorus in Jackson Reservoir, the reservoirs acted as a sink for both nitrogen and phosphorus; the percentage of the total mass (initial storage plus inflows) trapped in the reservoirs during the study period ranged from 49 to 88 percent for nitrogen and from 20 to 86 percent for phosphorus. The nutrient loading, morphology, and operation of the five reservoirs differed, however, leading to several important differences in nutrient dynamics among the reservoirs. Mean nutrient concentrations during the study period decreased in a downstream direction from Riverside Reservoir to Julesburg Reservoir because concentrations in the source water?the South Platte River?decreased downstream as a result of increased distance from wastewater loading upstream from Kersey, Colorado, and the replacement of diverted river water with more dilute ground-water return flow. North Sterling was an exception to this decrease; the strong stratification and resulting anoxia that developed in the reservoir led to nutrient release from the bottom sediments that offset the decrease in external nutrient loading. Variations in nutrient loading also contributed to differences in the nutrient limiting algal growth in the reservoirs, as indicated by mass nitrogen:phosphorus ratios. In Riverside and Jackson Reservoirs, nitrogen became the potential limiting nutrient by midsummer as biological activity depleted the available supply of nitrogen while the high initial phosphorus load was recycled. Prewitt, North Sterling, and Julesburg Reservoirs, with lower initial loadings of phosphorus, were phosphorus-limited throughout the study period, with additional colimitation of nitrogen as biological uptake reduced nitrogen concentrations to near or below laboratory detection limits. The percentage of the total nitrogen and phosphorus mass lost through outflow and trapped in the reservoir due to processes such as biological uptake and sedimentation varied between reservoirs.Generally, reservoirs with short residence times such as North Ste

Study on the quantitative relationship between Agricultural water and fertilization process and non-point source pollution based on field experiments

NASA Astrophysics Data System (ADS)

Wang, H.; Chen, K.; Wu, Z.; Guan, X.

2017-12-01

In recent years, with the prominent of water environment problem and the relative increase of point source pollution governance, especially the agricultural non-point source pollution problem caused by the extensive use of fertilizers and pesticides has become increasingly aroused people's concern and attention. In order to reveal the quantitative relationship between agriculture water and fertilizer and non-point source pollution, on the basis of elm field experiment and combined with agricultural drainage irrigation model, the agricultural irrigation water and the relationship between fertilizer and fertilization scheme and non-point source pollution were analyzed and calculated by field emission intensity index. The results show that the variation of displacement varies greatly under different irrigation conditions. When the irrigation water increased from 22cm to 42cm, the irrigation water increased by 20 cm while the field displacement increased by 11.92 cm, about 66.22% of the added value of irrigation water. Then the irrigation water increased from 42 to 68, irrigation water increased 26 cm, and the field displacement increased by 22.48 cm, accounting for 86.46% of irrigation water. So there is an "inflection point" between the irrigation water amount and field displacement amount. The load intensity increases with the increase of irrigation water and shows a significant power correlation. Under the different irrigation condition, the increase amplitude of load intensity with the increase of irrigation water is different. When the irrigation water is smaller, the load intensity increase relatively less, and when the irrigation water increased to about 42 cm, the load intensity will increase considerably. In addition, there was a positive correlation between the fertilization and load intensity. The load intensity had obvious difference in different fertilization modes even with same fertilization level, in which the fertilizer field unit load intensity increased the most in July. The results provide some basis for the field control and management of agricultural non-point source pollution.

Sewage-derived nutrient dynamics in highly urbanized coastal rivers, western Japan

NASA Astrophysics Data System (ADS)

Onodera, S. I.; Saito, M.; Jin, G.; Taniguchi, M.

2016-12-01

Water pollution by domestic sewage is one of the critical environmental problems in the early stage of urbanization with significant growth of population. In case of Osaka metropolitan area in Japan, the pollution was significant until 1970s, while it has been improved by the development of sewage treatment systems. However, removal of nitrogen needs the advanced process therefore relatively large part of dissolved inorganic nitrogen (DIN) is usually discharged by treated sewage effluent. Besides, increase of sewage-derived pollutant loads through the combined sewage systems during rainfall events is recognized as a new problem in recent years. However, the impacts of sewage-derived loads on the water environment of river and coastal area have not been fully evaluated in previous studies. In the present research, we aimed to examine the dynamics of sewage-derived nutrients in highly urbanized coastal rivers. Study area is located on the coastal area of Osaka bay in Seto Inland Sea, western Japan. Treated sewage effluent is discharged from three sewage treatment plants (KH, SU and SA) to a river and channels. Water and sediment samples were collected and electric conductivity (EC), chlorophyll-a (Chl.-a) and dissolved oxygen concentration (DO) were measured from the discharging points to few kilometers offshore at 100-300 m intervals. Nutrients (nitrogen, phosphorus and silica), nitrogen and carbon contents and stable isotope ratios (δ15N and δ13C) of particulate organic matter (POM) and sediment, nitrogen and oxygen stable isotope ratios (δ15N and δ18O) in nitrate (NO3-) were measured. Nitrate-nitrogen (NO3-N) concentration were significantly high near the discharging point then it decreased to offshore suggesting that impact zone of sewage effluent is about 1 km from the discharging point. Significant NO3-N uptake by phytoplankton as well as dilution process were suggested in the area. However, the impact zone expanded more than twofold during the rainfall event (>20mm/h). Nutrient contents were significantly high both in the sediment and pore water near the discharging points and it caused relatively high diffusion flux to overlying water. It suggests nutrient regeneration process from the sediment is the secondary loading process in the study area.

Decline in eelgrass ( Zostera marina L.) in Long Island Sound near Millstone Point, Connecticut (USA) unrelated to thermal input

NASA Astrophysics Data System (ADS)

Keser, Milan; Swenarton, John T.; Vozarik, Joseph M.; Foertch, James F.

2003-02-01

Eelgrass ( Zostera marina L.) shoot density, seed-bearing shoot abundance, shoot length, and standing stock biomass were monitored during summer months from 1985 to 2000 at three locations in eastern Long Island Sound (LIS) near Millstone Power Station (MPS), Waterford, Connecticut, USA. Short-term declines in eelgrass abundance were directly associated with fouling and overgrowth of eelgrass on two occasions; once by blue mussels ( Mytilus edulis) and once by a bloom of green algae ( Cladophora spp.). Analysis of long-term trends indicated some degree of decline in most of the parameters examined at all three areas monitored. The spatial relationship of the long-term eelgrass declines suggests primary causal factors other than the power plant discharge or regional climate change. Two populations to the east of MPS and near the fringes of the thermal plume (<1.5 km from the MPS discharge to LIS) exhibited only slight declines over the 16-y study period and thermal input from MPS to these sites was minimal (<1 °C above ambient conditions). By comparison, heavy eelgrass losses were documented in the Niantic River, located >2 km from the power plant thermal plume. Die-offs of entire individual eelgrass study beds in the Niantic River were observed on five separate occasions during the study with no sign of recovery. While the causes were not determined, anthropogenic influences such as nutrient loading from surface run-off and groundwater sources may have contributed to observed declines. The Niantic River has a more restricted tidal inlet and is closer to sources of nutrient enrichment than Jordan Cove. Historically, eelgrass has ranged to far western reaches of LIS, but over the last century has become restricted to the easternmost third of the Connecticut coastline due to nutrient loading and eutrophication of the western portions. This study suggests that the west-to-east declining trend in eelgrass distribution in LIS may be further progressing.

Groundwater-driven nutrient inputs to coastal lagoons: The relevance of lagoon water recirculation as a conveyor of dissolved nutrients.

PubMed

Rodellas, Valentí; Stieglitz, Thomas C; Andrisoa, Aladin; Cook, Peter G; Raimbault, Patrick; Tamborski, Joseph J; van Beek, Pieter; Radakovitch, Olivier

2018-06-16

Evaluating the sources of nutrient inputs to coastal lagoons is required to understand the functioning of these ecosystems and their vulnerability to eutrophication. Whereas terrestrial groundwater processes are increasingly recognized as relevant sources of nutrients to coastal lagoons, there are still limited studies evaluating separately nutrient fluxes driven by terrestrial groundwater discharge and lagoon water recirculation through sediments. In this study, we assess the relative significance of these sources in conveying dissolved inorganic nutrients (NO 3 - , NH 4 + and PO 4 3- ) to a coastal lagoon (La Palme lagoon; France, Mediterranean Sea) using concurrent water and radon mass balances. The recirculation of lagoon water through sediments represents a source of NH 4 + (1900-5500 mol d -1 ) and PO 4 3- (22-71 mol d -1 ), but acts as a sink of NO 3 - . Estimated karstic groundwater-driven inputs of NO 3 - , NH 4 + and PO 4 3- to the lagoon are on the order of 200-1200, 1-12 and 1.5-8.7 mol d -1 , respectively. A comparison between the main nutrient sources to the lagoon (karstic groundwater, recirculation, diffusion from sediments, inputs from a sewage treatment plant and atmospheric deposition) reveals that the recirculation of lagoon water through sediments is the main source of both dissolved inorganic nitrogen (DIN) and phosphorous (DIP) to La Palme lagoon. These results are in contrast with several studies conducted in systems influenced by terrestrial groundwater inputs, where groundwater is often assumed to be the main pathway for dissolved inorganic nutrient loads. This work highlights the important role of lagoon water recirculation through permeable sediments as a major conveyor of dissolved nutrients to coastal lagoons and, thus, the need for a sound understanding of the recirculation-driven nutrient fluxes and their ecological implications to sustainably manage lagoonal ecosystems. Copyright © 2018. Published by Elsevier B.V.

Reduced nutrient pollution in a rural stream following septic tank upgrade and installation of runoff retention measures.

PubMed

Ockenden, M C; Quinton, J N; Favaretto, N; Deasy, C; Surridge, B

2014-07-01

Surface water quality in the UK and much of Western Europe has improved in recent decades, in response to better point source controls and the regulation of fertilizer, manure and slurry use. However, diffuse sources of pollution, such as leaching or runoff of nutrients from agricultural fields, and micro-point sources including farmyards, manure heaps and septic tank sewerage systems, particularly systems without soil adsorption beds, are now hypothesised to contribute a significant proportion of the nutrients delivered to surface watercourses. Tackling such sources in an integrated manner is vital, if improvements in freshwater quality are to continue. In this research, we consider the combined effect of constructing small field wetlands and improving a septic tank system on stream water quality within an agricultural catchment in Cumbria, UK. Water quality in the ditch-wetland system was monitored by manual sampling at fortnightly intervals (April-October 2011 and February-October 2012), with the septic tank improvement taking place in February 2012. Reductions in nutrient concentrations were observed through the catchment, by up to 60% when considering total phosphorus (TP) entering and leaving a wetland with a long residence time. Average fluxes of TP, soluble reactive phosphorus (SRP) and ammonium-N (NH4-N) at the head of the ditch system in 2011 (before septic tank improvement) compared to 2012 (after septic tank improvement) were reduced by 28%, 9% and 37% respectively. However, TP concentration data continue to show a clear dilution with increasing flow, indicating that the system remained point source dominated even after the septic tank improvement.

Historical trend of nitrogen and phosphorus loads from the upper Yangtze River basin and their responses to the Three Gorges Dam.

PubMed

Sun, Chengchun; Shen, Zhenyao; Liu, Ruimin; Xiong, Ming; Ma, Fangbing; Zhang, Ouyang; Li, Yangyang; Chen, Lei

2013-12-01

Excessive inputs of nitrogen and phosphorus (N and P) degrade surface water quality worldwide. Impoundment of reservoirs alters the N and P balance of a basin. In this study, riverine nutrient loads from the upper Yangtze River basin (YRB) at the Yichang station were estimated using Load Estimator (LOADEST). Long-term load trends and monthly variabilities during three sub-periods based on the construction phases of the Three Gorges Dam (TGD) were analyzed statistically. The dissolved inorganic nitrogen (DIN) loads from the upper YRB for the period from 1990 to 2009 ranged from 30.47 × 10(4) to 78.14 × 10(4) t, while the total phosphorus (TP) loads ranged from 2.54 × 10(4) to 7.85 × 10(4) t. DIN increased rapidly from 1995 to 2002 mainly as a result of increased fertilizer use. Statistics of fertilizer use in the upper YRB agreed on this point. However, the trend of the TP loads reflected the combined effect of removal by sedimentation in reservoirs and increased anthropogenic inputs. After the TGD impoundment in 2003, decreasing trends in both DIN and TP loads were found. The reduction in DIN was mainly caused by ammonium consumption and transference. From an analysis of monthly loads, it was found that DIN had a high correlation to discharges. For TP loads, an average decrease of 4.91 % in October was found when the TGD impoundment occurred, but an increase of 4.23 % also occurred in July, corresponding to the washout from sediment deposited in the reservoir before July. Results of this study revealed the TGD had affected nutrient loads in the basin, and it had played a role in nutrient reduction after its operation.

Watershed delineation and nitrogen source analysis for Bayou ...

EPA Pesticide Factsheets

Nutrient pollution in stormwater runoff from urbanized areas contributes to water quality degradation in streams and receiving waterbodies. Agriculture, population growth, and industrial activities are significant sources of nitrogen inputs for surface waters. Increased nitrogen loading stimulates eutrophication through algal blooms, which leads to an overall decrease in drinking water and aquatic habitat quality. Bayou Chico, a highly urbanized watershed in the Pensacola Bay system in northwest Florida, is a nutrient-impaired waterbody under management to reduce bacteria and nutrient loadings, in accordance with the Florida Department of Environmental Protection’s (FDEP) Basin Management Action Plan. Best management practices and green infrastructure (GI) throughout Bayou Chico help reduce nitrogen inputs by retaining and filtering water. GI can function as a nitrogen sink by sorption or infiltration into soils, sequestration into plant material, and denitrification through microbial processes. However, a better understanding of the efficiency of these systems is needed to better inform management practices on future nitrogen reduction. This project will address two issues relating to the presence of nitrogen in the Bayou Chico watershed: 1) the identification of specific nitrogen sources within urbanized areas, and 2) the potential rates of nitrogen removal and sequestration from GI and nitrogen transport throughout the bayou. To accomplish these goals, nitr

Sediment Budgets and Sources Inform a Novel Valley Bottom Restoration Practice Impacted by Legacy Sediment: The Big Spring Run, PA, Restoration Experiment

NASA Astrophysics Data System (ADS)

Walter, R. C.; Merritts, D.; Rahnis, M. A.; Gellis, A.; Hartranft, J.; Mayer, P. M.; Langland, M.; Forshay, K.; Weitzman, J. N.; Schwarz, E.; Bai, Y.; Blair, A.; Carter, A.; Daniels, S. S.; Lewis, E.; Ohlson, E.; Peck, E. K.; Schulte, K.; Smith, D.; Stein, Z.; Verna, D.; Wilson, E.

2017-12-01

Big Spring Run (BSR), a small agricultural watershed in southeastern Pennsylvania, is located in the Piedmont Physiographic Province, which has the highest nutrient and sediment yields in the Chesapeake Bay watershed. To effectively reduce nutrient and sediment loading it is important to monitor the effect of management practices on pollutant reduction. Here we present results of an ongoing study, begun in 2008, to understand the impact of a new valley bottom restoration strategy for reducing surface water sediment and nutrient loads. We test the hypotheses that removing legacy sediments will reduce sediment and phosphorus loads, and that restoring eco-hydrological functions of a buried Holocene wetland (Walter & Merritts 2008) will improve surface and groundwater quality by creating accommodation space to trap sediment and process nutrients. Comparisons of pre- and post-restoration gage data show that restoration lowered the annual sediment load by at least 118 t yr-1, or >75%, from the 1000 m-long restoration reach, with the entire reduction accounted for by legacy sediment removal. Repeat RTK-GPS surveys of pre-restoration stream banks verified that >90 t yr-1 of suspended sediment was from bank erosion within the restoration reach. Mass balance calculations of 137Cs data indicate 85-100% of both the pre-restoration and post-restoration suspended sediment storm load was from stream bank sources. This is consistent with trace element data which show that 80-90 % of the pre-restoration outgoing suspended sediment load at BSR was from bank erosion. Meanwhile, an inventory of fallout 137Cs activity from two hill slope transects adjacent to BSR yields average modern upland erosion rates of 2.7 t ha-1 yr-1 and 5.1 t ha-1 yr-1, showing modest erosion on slopes and deposition at toe of slopes. We conclude that upland farm slopes contribute little soil to the suspended sediment supply within this study area, and removal of historic valley bottom sediment effectively reduced bank erosion and sediment and phosphorus loads. Enhanced deposition further contributed to load reductions; prior to restoration, there was no deposition on tile pads on the 1.5 m-high legacy sediment "floodplain" terrace, whereas after restoration deposition on the low, restored floodplain showed net accumulation of 0.009 ± 0.012 m yr-1.

Symplasmic transport and phloem loading in gymnosperm leaves

PubMed Central

Liesche, Johannes; Martens, Helle Juel

2010-01-01

Despite more than 130 years of research, phloem loading is far from being understood in gymnosperms. In part this is due to the special architecture of their leaves. They differ from angiosperm leaves among others by having a transfusion tissue between bundle sheath and the axial vascular elements. This article reviews the somewhat inaccessible and/or neglected literature and identifies the key points for pre-phloem transport and loading of photoassimilates. The pre-phloem pathway of assimilates is structurally characterized by a high number of plasmodesmata between all cell types starting in the mesophyll and continuing via bundle sheath, transfusion parenchyma, Strasburger cells up to the sieve elements. Occurrence of median cavities and branching indicates that primary plasmodesmata get secondarily modified and multiplied during expansion growth. Only functional tests can elucidate whether this symplasmic pathway is indeed continuous for assimilates, and if phloem loading in gymnosperms is comparable with the symplasmic loading mode in many angiosperm trees. In contrast to angiosperms, the bundle sheath has properties of an endodermis and is equipped with Casparian strips or other wall modifications that form a domain border for any apoplasmic transport. It constitutes a key point of control for nutrient transport, where the opposing flow of mineral nutrients and photoassimilates has to be accommodated in each single cell, bringing to mind the principle of a revolving door. The review lists a number of experiments needed to elucidate the mode of phloem loading in gymnosperms. PMID:21107620

A modeling study examining the impact of nutrient boundaries ...

EPA Pesticide Factsheets

A mass balance eutrophication model, Gulf of Mexico Dissolved Oxygen Model (GoMDOM), has been developed and applied to describe nitrogen, phosphorus and primary production in the Louisiana shelf of the Gulf of Mexico. Features of this model include bi-directional boundary exchanges, an empirical site-specific light attenuation equation, estimates of 56 river loads and atmospheric loads. The model was calibrated for 2006 by comparing model output to observations in zones that represent different locations in the Gulf. The model exhibited reasonable skill in simulating the phosphorus and nitrogen field data and primary production observations. The model was applied to generate a nitrogen mass balance estimate, to perform sensitivity analysis to compare the importance of the nutrient boundary concentrations versus the river loads on nutrient concentrations and primary production within the shelf, and to provide insight into the relative importance of different limitation factors on primary production. The mass budget showed the importance of the rivers as the major external nitrogen source while the atmospheric load contributed approximately 2% of the total external load. Sensitivity analysis showed the importance of accurate estimates of boundary nitrogen concentrations on the nitrogen levels on the shelf, especially at regions further away from the river influences. The boundary nitrogen concentrations impacted primary production less than nitrogen concent

How phosphorus limitation can control climate-active gas sources and sinks

NASA Astrophysics Data System (ADS)

Gypens, Nathalie; Borges, Alberto V.; Ghyoot, Caroline

2017-06-01

Since the 1950's, anthropogenic activities have increased nutrient river loads to European coastal areas. Subsequent implementation of nutrient reduction policies have led to considerably reduction of phosphorus (P) loads from the mid-1980's, while nitrogen (N) loads were maintained, inducing a P limitation of phytoplankton growth in many eutrophied coastal areas such as the Southern Bight of the North Sea (SBNS). When dissolved inorganic phosphorus (DIP) is limiting, most phytoplankton organisms are able to indirectly acquire P from dissolved organic P (DOP). We investigate the impact of DOP use on phytoplankton production and atmospheric fluxes of CO2 and dimethylsulfide (DMS) in the SBNS from 1951 to 2007 using an extended version of the R-MIRO-BIOGAS model. This model includes a description of the ability of phytoplankton organisms to use DOP as a source of P. Results show that primary production can increase up to 30% due to DOP uptake under limiting DIP conditions. Consequently, simulated DMS emissions also increase proportionally while CO2 emissions to the atmosphere decrease, relative to the reference simulation without DOP uptake.

Inputs and internal cycling of nitrogen to a causeway influenced, hypersaline lake, Great Salt Lake, Utah, USA

USGS Publications Warehouse

Naftz, David L.

2017-01-01

Nitrogen inputs to Great Salt Lake (GSL), located in the western USA, were quantified relative to the resident nitrogen mass in order to better determine numeric nutrient criteria that may be considered at some point in the future. Total dissolved nitrogen inputs from four surface-water sources entering GSL were modeled during the 5-year study period (2010–2014) and ranged from 1.90 × 106 to 5.56 × 106 kg/year. The railroad causeway breach was a significant conduit for the export of dissolved nitrogen from Gilbert to Gunnison Bay, and in 2011 and 2012, net losses of total nitrogen mass from Gilbert Bay via the Causeway breach were 9.59 × 105 and 1.51 × 106 kg. Atmospheric deposition (wet + dry) was a significant source of nitrogen to Gilbert Bay, exceeding the dissolved nitrogen load contributed via the Farmington Bay causeway surface-water input by >100,000 kg during 2 years of the study. Closure of two railroad causeway culverts in 2012 and 2013 likely initiated a decreasing trend in the volume of the higher density Deep Brine Layer and associated declines in total dissolved nitrogen mass contained in this layer. The large dissolved nitrogen pool in Gilbert Bay relative to the amount of nitrogen contributed by surface-water inflow sources is consistent with the terminal nature of GSL and the predominance of internal nutrient cycling. The opening of the new railroad causeway breach in 2016 will likely facilitate more efficient bidirectional flow between Gilbert and Gunnison Bays, resulting in potentially substantial changes in nutrient pools within GSL.

Nitrate Sources and Transport in the Upper Illinois River Basin Evaluated with Stable Isotope Ratios and SWAT Modeling

NASA Astrophysics Data System (ADS)

Lin, J.; Demissie, Y.; Yan, E.; Bohlke, J. K.; Sturchio, N. C.

2014-12-01

Measurements of nitrate concentrations and δ15N and δ18O values in 450 surface-water samples from the Upper Illinois River Basin (UIRB) were combined with SWAT (Soil and Water Assessment Tool) modeling to study the influence of land use on nitrate sources, mixing, and transformation within the watershed. The samples were collected from the Illinois River and its tributaries, including effluent from Chicago's largest wastewater treatment plant (WTP), October 2004 through October 2008. The isotopic and concentration measurements indicated that WTP effluent and agricultural drainage waters were the two principal nitrate endmembers within the UIRB. Isotopic compositions indicated the source of nitrate during the annual spring flushing event was mostly derived from agriculture. An apparent denitrification trend was identified from spring through fall in tributaries draining agricultural subbasins and those having mixed urban-agricultural land use. Mass balance indicated that the fraction of nitrate from the WTP effluent was as low as 5 % or less during the spring flush (March-May) and much larger during late summer and fall. A SWAT model was constructed to evaluate effects of land use, fertilizer applications, and WTP point source discharge by coupling hydrologic processes with nutrient cycling and plant growth. The UIRB SWAT model was calibrated and validated with flow and nitrate measurements: the Nash-Sutcliffe efficiency (NSE) ranged from 0.60 to 0.83 and the determination coefficient (R2) ranged from 0.59 to 0.87. To explore the influence of fertilizer input on basin nitrate transport, the calibrated model was used to evaluate impacts of spring and fall fertilizer applications on stream nitrate loads. Simulations with a -50% change in the total fertilizer application rate (kg N/ha) resulted in as much as -42% change in basin nitrate export (kg N/month), while causing only -9% or less change in corn yield (kg N/ha). Decreased fertilizer application also led to reductions of annual basin N percolation rate below the root zone (kg N/ha) and nitrate loading to surface runoff (kg N/ha), causing changes as much as -32.2% and -15.6% respectively. Combined modeling and isotopic studies can be useful for understanding nutrient mixing and transformation processes and for optimizing nutrient export reduction strategies.

Relations of surface-water quality to streamflow in the Raritan River basin, New Jersey, water years 1976-93

USGS Publications Warehouse

Buxton, Debra E.; Hunchak-Kariouk, Kathryn; Hickman, R. Edward

1999-01-01

Relations of water quality to streamflow were determined for 18 water-quality constituents at 21 surface-water stations within the drainage area of the Raritan River Basin for water years 1976-93. Surface-water-quality and streamflow data were evaluated for trends (through time) in constituent concentrations during high and low flows, and relations between constituent concentration and streamflow, and between constituent load and streamflow, were determined. Median concentrations were calculated for the entire period of study (water years 1976-93) and for the last 5 years of the period of study (water years 1989-93) to determine whether any large variation in concentration exists between the two periods. Medians also were used to determine the seasonal Kendall’s tau statistic, which was then used to evaluate trends in concentrations during high and low flows. Trends in constituent concentrations during high and low flows were evaluated to determine whether the distribution of the observations changes through time for intermittent (nonpoint storm runoff) or constant (point sources and ground water) sources, respectively. Highand low-flow trends in concentrations were determined for some constituents at 13 of the 21 water-quality stations; 8 stations have insufficient data to determine trends. Seasonal effects on the relations of concentration to streamflow are evident for 16 of the 18 constituents. Negative slopes of relations of concentration to streamflow, which indicate a decrease in concentration at high flows, predominate over positive slopes because of the dilution of instream concentrations by storm runoff. The slopes of the regression lines of load to streamflow were determined in order to show the relative contributions to the instream load from constant (point sources and ground water) and intermittent sources (storm runoff). Greater slope values indicate larger contributions from storm runoff to instream load, which most likely indicate an increased relative importance of nonpoint sources. The slopes of load-to-streamflow relations along a stream reach that tend to increase in a downstream direction indicate the increased relative importance of contributions from storm runoff. The slopes of load-to-streamflow relations increase in the downstream direction for alkalinity at North Branch Raritan and Millstone Rivers, for some or all of the nutrient species at South Branch and North Branch Raritan Rivers, for hardness at South Branch Raritan River, for dissolved solids at North Branch Raritan River, for dissolved sodium at Lamington River, and for suspended sediment and dissolved oxygen at Millstone River. Likewise, the slopes of load-tostreamflow relations along a stream reach that tend to decrease in a downstream direction indicate the increased relative importance of point sources and ground-water discharge. The slopes of load-to-streamflow relations decrease in the downstream direction for dissolved solids at Raritan and Millstone Rivers; for dissolved sodium, dissolved chloride, total ammonia plus organic nitrogen, and total ammonia at South Branch Raritan, Raritan, and Millstone Rivers; for dissolved oxygen at North Branch Raritan and Lamington Rivers; for total nitrite at Lamington, Raritan, and Millstone Rivers; for total boron at South Branch Raritan and Millstone Rivers; for total organic carbon at North Branch Raritan River; for suspended sediment and total nitrogen at Raritan River; and for hardness, total phosphorus, and total lead at Millstone River.

In-time source tracking of watershed loads of Taihu Lake Basin, China based on spatial relationship modeling.

PubMed

Wang, Ce; Bi, Jun; Zhang, Xu-Xiang; Fang, Qiang; Qi, Yi

2018-05-25

Influent river carrying cumulative watershed load plays a significant role in promoting nuisance algal bloom in river-fed lake. It is most relevant to discern in-stream water quality exceedance and evaluate the spatial relationship between risk location and potential pollution sources. However, no comprehensive studies of source tracking in watershed based on management grid have been conducted for refined water quality management, particularly for plain terrain with complex river network. In this study, field investigations were implemented during 2014 in Taige Canal watershed of Taihu Lake Basin. A Geographical Information System (GIS)-based spatial relationship model was established to characterize the spatial relationships of "point (point-source location and monitoring site)-line (river segment)-plane (catchment)." As a practical exemplification, in-time source tracking was triggered on April 15, 2015 at Huangnianqiao station, where TN and TP concentration violated the water quality standard (TN 4.0 mg/L, TP 0.15 mg/L). Of the target grid cells, 53 and 46 were identified as crucial areas having high pollution intensity for TN and TP pollution, respectively. The estimated non-point source load in each grid cell could be apportioned into different source types based on spatial pollution-related entity objects. We found that the non-point source load derived from rural sewage and livestock and poultry breeding accounted for more than 80% of total TN or TP load than another source type of crop farming. The approach in this study would be of great benefit to local authorities for identifying the serious polluted regions and efficiently making environmental policies to reduce watershed load.

Effect of algal blooms on retention of N, Si and P in Europe's largest coastal lagoon

NASA Astrophysics Data System (ADS)

Vybernaite-Lubiene, I.; Zilius, M.; Giordani, G.; Petkuviene, J.; Vaiciute, D.; Bukaveckas, P. A.; Bartoli, M.

2017-07-01

Nutrient fluxes from land to sea are regulated by climatic factors governing hydrologic loading rates (e.g., storm events, snowmelt) and by internal processes within estuaries that affect nutrient transformation and retention. We compared monthly input and output fluxes of N, Si, and P at the entrance and exit of the hypereutrophic Curonian Lagoon to better understand how seasonal changes in the stoichiometry of nutrient inputs and the occurrence of algal blooms affected nutrient retention within the lagoon. Nutrient ratios were indicative of increasing Si and N limitation during the growing season, and these were associated with a shift from a diatom-based to a cyanobacteria dominated phytoplankton community. The estuary was a net sink for dissolved nutrients, but we observed large interannual difference in the overall retention of N and P. The occurrence of a large cyanobacteria bloom in 2012 was associated with increased export of particulate matter to the Baltic Sea resulting in a net surplus of P export. Bloom conditions mobilized P from sediments and resulted in a shift from net retention to net export for the lagoon. The findings of our study illustrate how changes in nutrient loading ratios influence phytoplankton community composition, which in turn alters the source-sink status of the estuary.

Groundwater impacts on surface water quality and nutrient loads in lowland polder catchments: monitoring the greater Amsterdam area

NASA Astrophysics Data System (ADS)

Yu, Liang; Rozemeijer, Joachim; van Breukelen, Boris M.; Ouboter, Maarten; van der Vlugt, Corné; Broers, Hans Peter

2018-01-01

The Amsterdam area, a highly manipulated delta area formed by polders and reclaimed lakes, struggles with high nutrient levels in its surface water system. The polders receive spatially and temporally variable amounts of water and nutrients via surface runoff, groundwater seepage, sewer leakage, and via water inlets from upstream polders. Diffuse anthropogenic sources, such as manure and fertiliser use and atmospheric deposition, add to the water quality problems in the polders. The major nutrient sources and pathways have not yet been clarified due to the complex hydrological system in lowland catchments with both urban and agricultural areas. In this study, the spatial variability of the groundwater seepage impact was identified by exploiting the dense groundwater and surface water monitoring networks in Amsterdam and its surrounding polders. A total of 25 variables (concentrations of total nitrogen (TN), total phosphorus (TP), NH4, NO3, HCO3, SO4, Ca, and Cl in surface water and groundwater, N and P agricultural inputs, seepage rate, elevation, land-use, and soil type) for 144 polders were analysed statistically and interpreted in relation to sources, transport mechanisms, and pathways. The results imply that groundwater is a large source of nutrients in the greater Amsterdam mixed urban-agricultural catchments. The groundwater nutrient concentrations exceeded the surface water environmental quality standards (EQSs) in 93 % of the polders for TP and in 91 % for TN. Groundwater outflow into the polders thus adds to nutrient levels in the surface water. High correlations (R2 up to 0.88) between solutes in groundwater and surface water, together with the close similarities in their spatial patterns, confirmed the large impact of groundwater on surface water chemistry, especially in the polders that have high seepage rates. Our analysis indicates that the elevated nutrient and bicarbonate concentrations in the groundwater seepage originate from the decomposition of organic matter in subsurface sediments coupled to sulfate reduction and possibly methanogenesis. The large loads of nutrient-rich groundwater seepage into the deepest polders indirectly affect surface water quality in the surrounding area, because excess water from the deep polders is pumped out and used to supply water to the surrounding infiltrating polders in dry periods. The study shows the importance of the connection between groundwater and surface water nutrient chemistry in the greater Amsterdam area. We expect that taking account of groundwater-surface water interaction is also important in other subsiding and urbanising deltas around the world, where water is managed intensively in order to enable agricultural productivity and achieve water-sustainable cities.

WATERSHEED NUTRIENT INPUTS, PHYTOPLANKTON ACCUMULATION, AND C STOCKS IN CHESAPEAKE BAY

EPA Science Inventory

Inputs of N and P to Chesapeake Bay have been enhanced by anthropogenic activities. Fertilizers, developed areas, N emissions, and industrial effluents contribute to point and diffuse sources currently 2-20X higher than those from undisturbed watersheds. Enhanced nutrient inputs ...

Organic Carbon Trends, Loads, and Yields to the Sacramento-San Joaquin Delta, California, Water Years 1980 to 2000

USGS Publications Warehouse

Saleh, Dina K.; Domagalski, Joseph L.; Kratzer, Charles R.; Knifong, Donna L.

2003-01-01

Organic carbon, nutrient, and suspended sediment concentration data were analyzed for the Sacramento and San Joaquin River Basins for the period 1980-2000. The data were retrieved from three sources: the U.S. Geological Survey's National Water Information System, the U.S. Environmental Protection Agency's Storage and Retrieval System, and the California Interagency Ecological Program's relational database. Twenty sites were selected, all of which had complete records of daily streamflow data. These data met the minimal requirements of the statistical programs used to estimate trends, loads, and yields. The seasonal Kendall program was used to estimate trends in organic carbon, nutrient, and suspended sediment. At all 20 sites, analyses showed that in the 145 analyses for the seven constituents, 95 percent of the analyses had no significant trend. Dissolved organic carbon (DOC) concentrations were significant only for four sites: the American River at Sacramento, the Sacramento River sites near Freeport, Orestimba Creek at River Roads near Crows Landing, and the San Joaquin River near Vernalis. Loads were calculated using two programs, ESTIMATOR and LOADEST2. The 1998 water year was selected to describe loads in the Sacramento River Basin. Organic carbon, nutrient, and suspended sediment loads at the Sacramento River sites near Freeport included transported loads from two main upstream sites: the Sacramento River at Verona and the American River at Sacramento. Loads in the Sacramento River Basin were affected by the amount of water diverted to the Yolo Bypass (the amount varies annually, depending on the precipitation and streamflow). Loads at the Sacramento River sites near Freeport were analyzed for two hydrologic seasons: the irrigation season (April to September) and the nonirrigation season (October to March). DOC loads are lower during the irrigation season then they are during the nonirrigation season. During the irrigation season, water with low concentrations of DOC is released from reservoirs and used for irrigation. On the other hand, during the nonirrigation season, streamflow results from surface water runoff and has higher concentrations of organic carbon, nutrients, and suspended sediment. The 1986 and 1987 water years were selected to describe loads in the San Joaquin River Basin. Organic carbon, nutrient, and suspended sediment loads in the San Joaquin River near Vernalis included transported loads from upstream sites, such as the Mud and Salt Sloughs, the Merced River at River Roads Bridge near Newman, the Tuolumne River at Modesto, and the Stanislaus River at Ripon. Loads at the San Joaquin River near Vernalis also were analyzed for the two seasons. The DOC load for the San Joaquin River at Vernalis is slightly higher during the irrigation season. Yields were calculated in an attempt to rank the subbasins in the Sacramento and San Joaquin River Basins. Five sites delivered streamflow from agricultural and urban sources that had relatively high yields of organic carbon: Sacramento Slough near Knights Landing, Arcade Creek near Del Paso Heights, Salt Slough, Mud Slough, and Colusa Basin Drain at Road 99E near Knights Landing.

Web-based Communication of Water Quality Issues and Potential Solution Exploration

EPA Science Inventory

Many United States water bodies are impaired, i.e., do not meet applicable water quality standards. Pollutants enter water bodies from point sources (PS) and non-point sources (NPS). Loadings from PS are regulated by the Clean Water Act and permits limit them. Loadings from NPS a...

SPARROW models used to understand nutrient sources in the Mississippi/Atchafalaya River Basin

USGS Publications Warehouse

Robertson, Dale M.; Saad, David A.

2013-01-01

Nitrogen (N) and phosphorus (P) loading from the Mississippi/Atchafalaya River Basin (MARB) has been linked to hypoxia in the Gulf of Mexico. To describe where and from what sources those loads originate, SPAtially Referenced Regression On Watershed attributes (SPARROW) models were constructed for the MARB using geospatial datasets for 2002, including inputs from wastewater treatment plants (WWTPs), and calibration sites throughout the MARB. Previous studies found that highest N and P yields were from the north-central part of the MARB (Corn Belt). Based on the MARB SPARROW models, highest N yields were still from the Corn Belt but centered over Iowa and Indiana, and highest P yields were widely distributed throughout the center of the MARB. Similar to that found in other studies, agricultural inputs were found to be the largest N and P sources throughout most of the MARB: farm fertilizers were the largest N source, whereas farm fertilizers, manure, and urban inputs were dominant P sources. The MARB models enable individual N and P sources to be defined at scales ranging from SPARROW catchments (∼50 km2) to the entire area of the MARB. Inputs of P from WWTPs and urban areas were more important than found in most other studies. Information from this study will help to reduce nutrient loading from the MARB by providing managers with a description of where each of the sources of N and P are most important, thus providing a basis for prioritizing management actions and ultimately reducing the extent of Gulf hypoxia.

The nutrient-load hypothesis: patterns of resource limitation and community structure driven by competition for nutrients and light.

PubMed

Brauer, Verena S; Stomp, Maayke; Huisman, Jef

2012-06-01

Resource competition theory predicts that the outcome of competition for two nutrients depends on the ratio at which these nutrients are supplied. Yet there is considerable debate whether nutrient ratios or absolute nutrient loads determine the species composition of phytoplankton and plant communities. Here we extend the classical resource competition model for two nutrients by including light as additional resource. Our results suggest the nutrient-load hypothesis, which predicts that nutrient ratios determine the species composition in oligotrophic environments, whereas nutrient loads are decisive in eutrophic environments. The underlying mechanism is that nutrient enrichment shifts the species interactions from competition for nutrients to competition for light, which favors the dominance of superior light competitors overshadowing all other species. Intermediate nutrient loads can generate high biodiversity through a fine-grained patchwork of two-species and three-species coexistence equilibria. Depending on the species traits, however, competition for nutrients and light may also produce multiple alternative stable states, suppressing the predictability of the species composition. The nutrient-load hypothesis offers a solution for several discrepancies between classical resource competition theory and field observations, explains why eutrophication often leads to diversity loss, and provides a simple conceptual framework for patterns of biodiversity and community structure observed in nature.

Investigation of the effects of slow-release fertilizer and struvite in biodegradation in filter drains and potential application of treated water in irrigation of road verges.

PubMed

Theophilus, Stephen C; Mbanaso, Fredrick U; Nnadi, Ernest O; Onyedeke, Kingsley T

2017-11-14

Filter drains are usually laid along the margins of highways. Highway runoffs are polluted with hydrocarbons and high levels of total dissolved solids. Therefore, effective pollution removal mechanism is necessary in order to avoid contamination of surrounding soils and groundwater. Biodegradation is amongst pollution removal mechanisms in filter drains, but it is a relatively slow process which is dependent on wide range of factors including the type of pollutant and availability of nutrients. This paper reports on a study conducted to investigate the impact of slow-release fertilizer and struvite in enhancement of biodegradation of hydrocarbon in filter drains. Filter drain models incorporated with geotextile were challenged with cumulative oil loading of 178 mg/m 2 /week with a view to comparing the efficiency of these two nutrient sources under high oil pollution loading and realistic rainfall conditions of 13 mm/week. Nutrients and street dust were applied at one-off rate of 17 g/m 2 and 1.55 g/rig to provide nutrient enhancement and simulate field conditions respectively. The impact of the nutrients was studied by monitoring bacterial and fungal growth using nutrient agar, Rose Bengal Agar media and CO2 evolution. EC, pH, heavy metals, TPH, elemental analysis and SAR were used to investigate water quality of effluent of filter drains for potential application as irrigation fluid for trees and flowers planted on road verges. The results show that nutrient application encouraged microbial activities and enhanced biodegradation rates with differences in type of nutrient applied. Also, it was observed that incorporation of geotextiles in filter drains improved pollution retention efficiency and there is a potential opportunity for utilization of struvite in SuDS systems as sustainable nutrient source.

Threshold values and management options for phosphorus in a catchment of an estuary in Denmark with poor ecological status

NASA Astrophysics Data System (ADS)

Kronvang, Brian; Windolf, Jørgen; Hinsby, Klaus; Markager, Stiig

2015-04-01

Assessment of the ecological status of an estuary in Denmark(Horsens estuary) indicate that beside reducing total N loads also total phosphorus (TP) loads should be reduced to a level corresponding to 56% of current TP loads to obtain a good ecological status as required by the EU Water Framework Directive (Hinsby et al., 2012). The estimated maximum acceptable TP load to the estuary amounting to 13 tonnes per year corresponds to a reduction of the current TP loadings (2000-2005) with an average of 10.4 tonnes P per year. The maximum allowed stream threshold TP concentration entering the estuary is then calculated to amount to 0.084 mg P L-1. A source apportionment of TP loads during the period 2000-2005 showed that point source emissions of TP contributed with 31% and diffuse sources including background loadings, agricultural losses and scattered dwellings contributed with the remaining 69% of the TP loadings to the estuary. The reduction targets for TP can be obtained by implementing different mitigation measures directed against diffuse losses in the catchment and introducing improved treatment of sewage water at point sources discharging either to freshwater or directly to the estuary. We developed a management option for the catchment and estuary that could be applied together with a reduction of the total nitrogen loadings in order to obtain a good ecological status in the Horsens estuary (Hinsby et al., 2012). The management scenario included a reduction of point source emissions of TP amounting to 4.14 tonnes P yr-1, restoration of 300 ha of riparian wetlands (3.0 tonnes P yr-1) and implementation of mandatory 10 m buffer strips with planting of trees along 300 km of watercourses (3.0 tonnes P yr-1). We find it impossible to calculate a threshold concentration for TP in groundwater within the catchment as the pathways of dissolved (leaching and groundwater discharges) and particulate (erosional) P forms are more complex than it is the case for nitrogen (Kronvang et al., 2007). The average concentration of total dissolved P (TDP) in aerobic groundwater in the catchment amounts to 0.018 mg P L-1, whereas it is much higher in anaerobic groundwater 0.130 mg P L-1. Knowledge on the distribution of groundwater between aerobic and anerobic groundwater within the catchment exists from the DK-model but TDP fluxes and especially emissions from groundwater to surface waters cannot be reliable estimated as part of TDP from anaerobic groundwater pathways is captured by sorption and precipitation processes in discharge areas before entering the watercourses as natural background concentrations of TDP in watercourses are much lower than could be estimated from the measured groundwater concentrations. References Hinsby, K., Markager, S., Kronvang, B., Windolf, J., Sonnenborg, T. and Thorling, L. 2012. Threshold values and management options for nutrients in a catchment of a temperate estuary with poor ecological status. Hydrology and Earth System Sciences 16(8): 2663-2683. Kronvang, B., Vagstad, N., Behrendt, H., Bogestrand, J, and Larsen, S. E. 2007 Phosphorus losses at the catchment scale within Europe: an overview, Soil Use Management., 23: 104-116.

Non-domestic phosphorus release in rivers during low-flow: Mechanisms and implications for sources identification

NASA Astrophysics Data System (ADS)

Dupas, Rémi; Tittel, Jörg; Jordan, Phil; Musolff, Andreas; Rode, Michael

2018-05-01

A common assumption in phosphorus (P) load apportionment studies is that P loads in rivers consist of flow independent point source emissions (mainly from domestic and industrial origins) and flow dependent diffuse source emissions (mainly from agricultural origin). Hence, rivers dominated by point sources will exhibit highest P concentration during low-flow, when flow dilution capacity is minimal, whereas rivers dominated by diffuse sources will exhibit highest P concentration during high-flow, when land-to-river hydrological connectivity is maximal. Here, we show that Soluble Reactive P (SRP) concentrations in three forested catchments free of point sources exhibited seasonal maxima during the summer low-flow period, i.e. a pattern expected in point source dominated areas. A load apportionment model (LAM) is used to show how point sources contribution may have been overestimated in previous studies, because of a biogeochemical process mimicking a point source signal. Almost twenty-two years (March 1995-September 2016) of monthly monitoring data of SRP, dissolved iron (Fe) and nitrate-N (NO3) were used to investigate the underlying mechanisms: SRP and Fe exhibited similar seasonal patterns and opposite to that of NO3. We hypothesise that Fe oxyhydroxide reductive dissolution might be the cause of SRP release during the summer period, and that NO3 might act as a redox buffer, controlling the seasonality of SRP release. We conclude that LAMs may overestimate the contribution of P point sources, especially during the summer low-flow period, when eutrophication risk is maximal.

Spatial distribution and assessment of nutrient pollution in Lake Toba using 2D-multi layers hydrodynamic model and DPSIR framework

NASA Astrophysics Data System (ADS)

Sunaryani, A.; Harsono, E.; Rustini, H. A.; Nomosatryo, S.

2018-02-01

Lake Toba is the largest lake in Indonesia utilized as a source of life-support for drinking and clean water, energy sources, aquaculture and tourism. Nowadays the water quality in Lake Toba has decreased due to the presence of excessive nutrient (nitrogen: N and phosphorus: P). This study aims to describe the spatial distribution of nutrient pollution and to develop a decision support tool for the identification and evaluation of nutrient pollution control in Lake Toba. Spatial distribution method was conducted by 2D-multi layers hydrodynamic model, while DPSIR Framework is used as a tool for the assessment. The results showed that the concentration of nutrient was low and tended to increase along the water depth, but nutrient concentration in aquaculture zones was very high and the trophic state index has reached eutrophic state. The principal anthropogenic driving forces were population growth and the development of aquaculture, livestock, agriculture, and tourism. The main environmental pressures showed that aquaculture and livestock waste are the most important nutrient sources (93% of N and 87% of P loads). State analysis showed that high nutrient concentration and increased algal growth lead to oxygen depletion. The impacts of these conditions were massive fish kills, loss of amenities and tourism value, also decreased usability of clean water supply. This study can be a useful information for decision-makers to evaluate nutrient pollution control. Nutrient pollution issue in Lake Toba requires the attention of local government and public society to maintain its sustainability.

Growth Responses of Three Dominant Wetland Plant Species to Various Flooding and Nutrient Levels

NASA Astrophysics Data System (ADS)

Barrett, S.; Shaffer, G. P.

2017-12-01

Coastal Louisiana is experiencing a greater rate of wetland loss than any other wetland system in the United States. This is primarily due to anthropogenic stressors such as flood control levees, backfilling and development of wetlands, and other hydrologic modifications. Methods employed to mitigate wetland loss include the construction of river diversions and assimilation wetlands, which can provide consistent sources of freshwater influx and nutrients to impounded swamps and marshes. It is well known that prolonged flooding causes strain on wetland plant communities and facilitates or exacerbates wetland degradation. However, because river diversions and assimilation wetlands bring high nutrient loads along with freshwater, there is debate over whether prolonged flooding or high influx of nutrients is the primary cause of stress in river diversion and assimilation wetland discharge areas. This mesocosm experiment addresses this question by isolating the effects of flooding and nutrients on the biomass of baldcypress (Taxodium distichum), maidencane (Panicum hemitomon), and cordgrass (Spartina patens) over the course of a growing season. The results of this study provide clarity as to whether flooding stress, high nutrient loads, or both cause a reduction in wetland plant productivity. By evaluating the growth responses of T. distichum, P. hemitomon, and S. patens at varying nutrient regimes, we gain insight on how these more dominant species will react to high nutrient discharges from large river diversions, such as those proposed in Louisiana's 2017 Master Plan.

Effects of agricultural nutrient management on nitrogen fate and transport in Lancaster County, Pennsylvania

USGS Publications Warehouse

Hall, D.W.; Risser, D.W.

1993-01-01

Nitrogen inputs to, and outputs from, a 55-acre site in Lancaster County, Pennsylvania, were estimated to determine the pathways and relative magnitude of loads of nitrogen entering and leaving the site, and to compare the loads of nitrogen before and after the implementation of nutrient management. Inputs of nitrogen to the site were manure fertilizer, commercial fertilizer, nitrogen in precipitation, and nitrogen in ground-water inflow; and these sources averaged 93, 4, 2, and 1 percent of average annual nitrogen additions, respectively. Outputs of nitrogen from the site were nitrogen in harvested crops, loads of nitrogen in surface runoff, volatilization of nitrogen, and loads of nitrogen in ground-water discharge, which averaged 37, less than 1,25, and 38 percent of average annual nitrogen removals from the site, respectively. Virtually all of the nitrogen leaving the site that was not removed in harvested crops or by volatilization was discharged in the ground water. Applications of manure and fertilizer nitrogen to 47.5 acres of cropped fields decreased about 33 percent, from an average of 22,700 pounds per year (480 pounds per acre per year) before nutrient management to 15,175 pounds of nitrogen per year (320 pounds per acre per year) after the implementation of nutrient management practices. Nitrogen loads in ground-water discharged from the site decreased about 30 percent, from an average of 292 pounds of nitrogen per million gallons of ground water before nutrient management to an average of 203 pounds of nitrogen per million gallons as a result of the decreased manure and commercial fertilizer applications. Reductions in manure and commercial fertilizer applications caused a reduction of approximately 11,000 pounds (3,760 pounds per year, 70 pounds per acre per year) in the load of nitrogen discharged in ground water from the 55-acre site during the three-year period 1987-1990.

Disentangling nutrient concentrations trends in transfer pathways of agricultural watersheds

NASA Astrophysics Data System (ADS)

Mellander, P. E.; Jordan, P.

2017-12-01

Targeted schemes designed to attenuate agricultural pollution to water are needed to reach goals of sustainable food production. Such approaches require insight into temporal and spatial variability in the most representative flows and active pollution transfer pathways. Interpreting changes in total stream flow can be misleading since some changes may only be apparent in specific pathways. The aim of this study was to investigate changing land use pressures on water quality. The objectives were to assess intra-annual and inter-annual changes in phosphorus (P) and nitrogen (N) concentrations and loads in apportioned pathways. Pathways were separated using hydrograph and loadograph separation techniques on a seven-year dataset of sub-hourly river discharge and concentrations of NO3-N, reactive P and total P in two intensively managed agricultural watersheds of contrasting hydrology in Ireland. Active transfer pathways were dictated by soil drainage. There were intra-annual variability in both P and N concentrations in different pathways and loads, and these had the largest influence of all-year baseflow (BF) concentrations and summer quickflow (QF) concentrations. Nutrient loss responded to seasonality in the river discharge in all pathways in both watersheds and was mostly transport limited. In both watersheds there were inter-annual trends in P concentration in some pathways and seasons that did not correspond to the trend of total river P concentration. The response in stream water quality to management, mitigation measures and changes in weather may be hidden by counteracting responses in different pathways. The hydrology had a major impact on seasonal changes in N and P loss. By apportioning different transfer pathways more information on the temporal and site-specific nature of nutrient transfer was provided. BF and QF pathways largely contributed to the river P concentrations in summer while all pathways contributed to the P and N loads in wintertime. The data indicated that increasing trends in river P concentrations were mostly linked to trends in BF concentration in both catchment types. This may be explained by increased point source influence, increased vertical transfer through increased soil P loading, or decreased stream bed attenuation. Each will require different policy considerations.

Integrated watershed approach in controlling point and non-point source pollution within Zelivka drinking water reservoir.

PubMed

Holas, J; Hrncir, M

2002-01-01

An agricultural watershed involves manipulation of soil, water and other natural resources and it has profound impacts on ecosystems. To manage these complex issues, we must understand causes and consequences and interactions-related transport of pollutants, quality of the environment, mitigation measures and policy measures. A ten year period of economic changes has been analysed with respect to sustainable development concerning Zelivka drinking water reservoir and its watershed, where agriculture and forestry are the main human activities. It is recommended that all land users within a catchment area should receive payments for their contribution to water cycle management. Setting up the prevention principles and best management practices financially subsidized by a local water company has been found very effective in both point and non-point source pollution abatement, and the newly prepared Clean Water Programme actively involves local municipal authorities as well. The first step based on systems analysis was to propose effective strategies and select alternative measures and ways for their financing. Long term monitoring of nutrient loads entering the reservoir and hazardous events statistics resulted in maps characterising the territory including vulnerable zones and risk factors. Financing involves providing annual payments to farmers, who undertake to manage specified areas of their land in a particular way and one-off payments to realise proposed issues ensuring soil conservation and watershed ecosystem benefits.

The estimation of the load of non-point source nitrogen and phosphorus based on observation experiments and export coefficient method in Three Gorges Reservoir Area

NASA Astrophysics Data System (ADS)

Tong, X. X.; Hu, B.; Xu, W. S.; Liu, J. G.; Zhang, P. C.

2017-12-01

In this paper, Three Gorges Reservoir Area (TGRA) was chosen to be the study area, the export coefficients of different land-use type were calculated through the observation experiments and literature consultation, and then the load of non-point source (NPS) nitrogen and phosphorus of different pollution sources such as farmland pollution sources, decentralized livestock and poultry breeding pollution sources and domestic pollution sources were estimated. The results show as follows: the pollution load of dry land is the main source of farmland pollution. The order of total nitrogen load of different pollution sources from high to low is livestock breeding pollution, domestic pollution, land use pollution, while the order of phosphorus load of different pollution sources from high to low is land use pollution, livestock breeding pollution, domestic pollution, Therefore, reasonable farmland management, effective control methods of dry land fertilization and sewage discharge of livestock breeding are the keys to the prevention and control of NPS nitrogen and phosphorus in TGRA.

How phosphorus limitation can control climatic gas sources and sinks

NASA Astrophysics Data System (ADS)

Gypens, Nathalie; Borges, Alberto V.; Ghyoot, Caroline

2017-04-01

Since the 1950's, anthropogenic activities severely increased river nutrient loads in European coastal areas. Subsequent implementation of nutrient reduction policies have considerably reduced phosphorus (P) loads from mid-1980's, while nitrogen (N) loads were maintained, inducing a P limitation of phytoplankton growth in many eutrophied coastal areas such as the Southern Bight of the North Sea (SBNS). When dissolved inorganic phosphorous (DIP) is limiting, most phytoplankton organisms are able to indirectly acquire P from dissolved organic P (DOP). We investigate the impact of DOP use on the importance of phytoplankton production and atmospheric fluxes of CO2 and dimethylsulfide (DMS) in the SBNS from 1951 to 2007 using an extended version of the R-MIRO-BIOGAS model. This model includes a description of the ability of phytoplankton organisms to use DOP as a source of P. Results show that primary production can increase up to 70% due to DOP uptake in limiting DIP conditions. Consequently, simulated DMS emissions double while CO2 emissions to the atmosphere decrease, relative to the reference simulation without DOP uptake. At the end of the simulated period (late 2000's), the net direction of air-sea CO2 annual flux, changed from a source to a sink for atmospheric CO2 in response to use of DOP and increase of primary production.

Summary of the river-quality assessment of the upper Chattahoochee River basin, Georgia

USGS Publications Warehouse

Cherry, R.N.; Faye, R.E.; Stamer, J.K.; Kleckner, R.L.

1980-01-01

The river-quality assessment of the Upper Chattahoochee River Basin included studies of (1) the impact of heat loads on river quality, (2) sediment transport and deposition, (3) magnitude and nature of point and nonpoint discharges, and (4) phytoplankton growth in the river and reservoirs. The combined thermal effects of flow regulation and powerplants effluents resulted in mean daily river temperature downstream of the powerplants about equal to or less than computed natural temperatures. The average annual river temperature in 1976 was 14.0 ? Celsius just upstream of the Atkinson-McDonough thermoelectric powerplants and 16.0 ? Celsius just downstream from the powerplants. During a low-flow period in June 1977 the heat load from the two powerplants caused an increase in river temperatures of about 7 ? Celsius and a subsequent decrease in the dissolved-oxygen concentration of about 0.2 milligrams per liter. During the June low-flow period, point sources contributed 63 percent of the ultimate biochemical oxygen demand and 97 percent of ammonium as nitrogen at the Franklin station. Oxidation of ultimate biochemical demand and ammonium caused dissolved-oxygen concentrations to decrease from about 8.0 milligrams per liter at river mile 299 to about 4.5 milligrams per liter at river mile 271. Dissolved orthophosphate is the nutrient presently limiting phytoplankton growth in the West Point Lake when water temperatures are greater than about 26 ? Celsius.

Effects of internal phosphorus loadings and food-web structure on the recovery of a deep lake from eutrophication

USGS Publications Warehouse

Lepori, Fabio; Roberts, James J.

2017-01-01

We used monitoring data from Lake Lugano (Switzerland and Italy) to assess key ecosystem responses to three decades of nutrient management (1983–2014). We investigated whether reductions in external phosphorus loadings (Lext) caused declines in lake phosphorus concentrations (P) and phytoplankton biomass (Chl a), as assumed by the predictive models that underpinned the management plan. Additionally, we examined the hypothesis that deep lakes respond quickly to Lext reductions. During the study period, nutrient management reduced Lext by approximately a half. However, the effects of such reduction on P and Chl a were complex. Far from the scenarios predicted by classic nutrient-management approaches, the responses of P and Chl a did not only reflect changes in Lext, but also variation in internal P loadings (Lint) and food-web structure. In turn, Lint varied depending on basin morphometry and climatic effects, whereas food-web structure varied due to apparently stochastic events of colonization and near-extinction of key species. Our results highlight the complexity of the trajectory of deep-lake ecosystems undergoing nutrient management. From an applied standpoint, they also suggest that [i] the recovery of warm monomictic lakes may be slower than expected due to the development of Lint, and that [ii] classic P and Chl a models based on Lext may be useful in nutrient management programs only if their predictions are used as starting points within adaptive frameworks.

Occurrence of dissolved solids, nutrients, atrazine, and fecal coliform bacteria during low flow in the Cheney Reservoir watershed, south-central Kansas, 1996

USGS Publications Warehouse

Christensen, V.G.; Pope, L.M.

1997-01-01

A network of 34 stream sampling sites was established in the 1,005-square-mile Cheney Reservoir watershed, south-central Kansas, to evaluate spatial variability in concentrations of selected water-quality constituents during low flow. Land use in the Cheney Reservoir watershed is almost entirely agricultural, consisting of pasture and cropland. Cheney Reservoir provides 40 to 60 percent of the water needs for the city of Wichita, Kansas. Sampling sites were selected to determine the relative contribution of point and nonpoint sources of water-quality constituents to streams in the watershed and to identify areas of potential water-quality concern. Water-quality constituents of interest included dissolved solids and major ions, nitrogen and phosphorus nutrients, atrazine, and fecal coliform bacteria. Water from the 34 sampling sites was sampled once in June and once in September 1996 during Phase I of a two-phase study to evaluate water-quality constituent concentrations and loading characteristics in selected subbasins within the watershed and into and out of Cheney Reservoir. Information summarized in this report pertains to Phase I and was used in the selection of six long-term monitoring sites for Phase II of the study. The average low-flow constituent concentrations in water collected during Phase I from all sampling sites was 671 milligrams per liter for dissolved solids, 0.09 milligram per liter for dissolved ammonia as nitrogen, 0.85 milligram per liter for dissolved nitrite plus nitrate as nitrogen, 0.19 milligram per liter for total phosphorus, 0.20 microgram per liter for dissolved atrazine, and 543 colonies per 100 milliliters of water for fecal coliform bacteria. Generally, these constituents were of nonpoint-source origin and, with the exception of dissolved solids, probably were related to agricultural activities. Dissolved solids probably occur naturally as the result of the dissolution of rocks and ancient marine sediments containing large salt deposits. Nutrients also may have resulted from point-source discharges from wastewater-treatment plants. An examination of water-quality characteristics during low flow in the Cheney Reservoir watershed provided insight into the spatial variability of water-quality constituents and allowed for between-site comparisons under stable-flow conditions; identified areas of the watershed that may be of particular water-quality concern; provided a preliminary evaluation of contributions from point and nonpoint sources of contamination; and identified areas of the watershed where long-term monitoring may be appropriate to quantify perceived water-quality problems.

Phytoplankton Community Structure, Biomass and Diversity on the Louisiana Continental Shelf

EPA Science Inventory

Phytoplankton communities on the Louisiana continental shelf (LCS) respond to nutrient loading from the Mississippi and Atchafalaya River Basin (MARB). Enhanced phytoplankton biomass is a source of organic matter contributing to the development of seasonal hypoxia. Samples were ...

Basin delineation and identification of nitrogen sources in an urban watershed

EPA Science Inventory

Nutrient pollution in stormwater runoff from urbanized areas contributes to water quality degradation in streams and receiving waterbodies. Increased nitrogen loading from human activities stimulates eutrophication through algal blooms, which leads to an overall decrease in drink...

Evaluating cumulative effects of anthropogenic inputs in Prince Edward Island estuaries using the mummichog (Fundulus heteroclitus).

PubMed

Finley, Megan A; Courtenay, Simon C; Teather, Kevin L; Hewitt, L Mark; Holdway, D A; Hogan, Natacha S; van den Heuvel, Michael R

2013-07-01

Estuarine eutrophication as a result of agricultural land use, including the use of chemical fertilizers, is increasing worldwide. Prince Edward Island (PEI), Canada has very high agricultural intensity by international standards with approximately 44% of the land area under production, and some watersheds in excess of 75% agricultural land-use. The type of agriculture is also intensive with primarily row crops that have high chemical fertilizer and pesticide usage. In light of these stressors, the hypothesis of this study was that mummichog (Fundulus heteroclitus) population parameters would change with point and nonpoint source pollution, and that multivariate statistics could be used to draw associations with specific stressors. Fish were sampled on a monthly basis from May through August at 7 estuaries spanning a range of land use, nutrient, and contaminant loadings. A suite of environmental variables were simplified into 3 principal components: PC1 representing agricultural land use, N loading, and plant habitat, PC2 being dominated by sediment sand and silt distribution, and PC3 largely reflecting P loading and sediment organic matter. There were significant differences in abundance of both adult and young-of-the-year mummichog, and these changes associated most strongly with PC1, the largely N-driven agricultural influences. In contrast, somatic variables such as liver and gonad size did not show strong association with the environmental quality principal component scores. The sand and silt PC2 appeared to have the opposite association with the biological data, with siltier environments correlating to older, larger, less dense populations of mummichog. Although pesticide residues were detected in estuarine sediment, there was no clear relationship between these and watershed agricultural intensity or biochemical indicators. There was, however, a strong relationship between agricultural environmental variables (PC1) and in vitro steroid production that is suggestive of a potential chemical effect. Eutrophication appeared to be a primary stressor affecting mummichog populations, as nutrient enrichment was associated with changes in habitat variables and these in turn were associated with high mummichog density. Thus, mummichog population demographics appear to have use as an indicator of adverse or worsening conditions in estuaries. We concluded that, based on the subset of environmental factors evaluated, the nonpoint-source inputs of sediments and nutrients exerted the greatest influence on mummichog populations in PEI estuaries. Copyright © 2013 SETAC.

THE ROLE OF STORMWATER BMPS IN MITIGATING THE EFFECTS OF NUTRIENT OVERENRICHMENT IN THE URBAN WATERSHED

EPA Science Inventory

Nutrient overenrichment from agricultural and urban point and nonpoint sources, including urban stormwter, is a leading cause of impairment to our nation's rivers, lakes, and coastal waters. For waters that do not currently meet existing water quality standards, The USEPA's TMDL ...

Fluvial sediment fingerprinting: literature review and annotated bibliography

USGS Publications Warehouse

Williamson, Joyce E.; Haj, Adel E.; Stamm, John F.; Valder, Joshua F.; Prautzch, Vicki L.

2014-01-01

The U.S. Geological Survey has evaluated and adopted various field methods for collecting real-time sediment and nutrient data. These methods have proven to be valuable representations of sediment and nutrient concentrations and loads but are not able to accurately identify specific source areas. Recently, more advanced data collection and analysis techniques have been evaluated that show promise in identifying specific source areas. Application of field methods could include studies of sources of fluvial sediment, otherwise referred to as sediment “fingerprinting.” The identification of sediment is important, in part, because knowing the primary sediment source areas in watersheds ensures that best management practices are incorporated in areas that maximize reductions in sediment loadings. This report provides a literature review and annotated bibliography of existing methodologies applied in the field of fluvial sediment fingerprinting. This literature review provides a bibliography of publications where sediment fingerprinting methods have been used; however, this report is not assumed to provide an exhaustive listing. Selected publications were categorized by methodology with some additional summary information. The information contained in the summary may help researchers select methods better suited to their particular study or study area, and identify methods in need of more testing and application.

Nutrient sequestration in Aquitaine lakes (SW France) limits nutrient flux to the coastal zone

NASA Astrophysics Data System (ADS)

Buquet, Damien; Anschutz, Pierre; Charbonnier, Céline; Rapin, Anne; Sinays, Rémy; Canredon, Axel; Bujan, Stéphane; Poirier, Dominique

2017-12-01

Oligotrophic coastal zones are disappearing from increased nutrient loading. The quantity of nutrients reaching the coast is determined not only by their original source (e.g. fertilizers used in agriculture, waste water discharges) and the land use, but also by the pathways through which nutrients are cycled from the source to the river mouth. In particular, lakes sequester nutrients and, hence, reduce downstream transfer of nutrients to coastal environments. Here, we quantify the impact of Aquitaine great lakes on the fluxes of dissolved macro-nutrients (N, P, Si) to the Bay of Biscay. For that, we have measured nutrient concentrations and fluxes in 2014 upstream and downstream lakes of Lacanau and Carcans-Hourtin, which belongs to the catchment of the Arcachon Bay, which is the largest coastal lagoon of the Bay of Biscay French coast. Data were compared to values obtained from the Leyre river, the main freshwater and nutrient source for the lagoon. Results show that processes in lakes greatly limit nutrient flux to the lagoon compared to fluxes from Leyre river, although the watershed is similar in terms of land cover. In lakes, phosphorus and silicon are trapped for long term in the sediment, silicon as amorphous biogenic silica and phosphorus as organic P and P associated with Fe-oxides. Nitrogen that enters lakes mostly as nitrate is used for primary production. N is mineralized in the sediment; a fraction diffuses as ammonium. N2 production through benthic denitrification extracts only 10% of dissolved inorganic nitrogen from the aquatic system. The main part is sequestered in organic-rich sediment that accumulates below 5 m depth in both lakes.

An evaluation of catchment-scale phosphorus mitigation using load apportionment modelling.

PubMed

Greene, S; Taylor, D; McElarney, Y R; Foy, R H; Jordan, P

2011-05-01

Functional relationships between phosphorus (P) discharge and concentration mechanisms were explored using a load apportionment model (LAM) developed for use in a freshwater catchment in Ireland with fourteen years of data (1995-2008). The aim of model conceptualisation was to infer changes in point and diffuse sources from catchment P loading during P mitigation, based upon a dataset comprising geospatial and water quality data from a 256km(2) lake catchment in an intensively farmed drumlin region of the midlands of Ireland. The model was calibrated using river total P (TP), molybdate reactive P (MRP) and runoff data from seven subcatchments. Temporal and spatial heterogeneity of P sources existed within and between subcatchments; these were attributed to differences in agricultural intensity, soil type and anthropogenically-sourced effluent P loading. Catchment rivers were sensitive to flow regime, which can result in eutrophication of rivers during summer and lake enrichment from frequent flood events. For one sewage impacted river, the LAM estimated that point sourced P contributed up to of 90% of annual MRP load delivered during a hydrological year and in this river point P sources dominated flows up to 92% of days. In the other rivers, despite diffuse P forming a majority of the annual P exports, point sources of P dominated flows for up to 64% of a hydrological year. The calibrated model demonstrated that lower P export rates followed specific P mitigation measures. The LAM estimated up to 80% decreases in point MRP load after enhanced P removal at waste water treatments plants in urban subcatchments and the implementation of septic tank and agricultural bye-laws in rural subcatchments. The LAM approach provides a way to assess the long-term effectiveness of further measures to reduce P loadings in EU (International) River Basin Districts and subcatchments. Copyright © 2011 Elsevier B.V. All rights reserved.

Occurrence of Surface Water Contaminations: An Overview

NASA Astrophysics Data System (ADS)

Shahabudin, M. M.; Musa, S.

2018-04-01

Water is a part of our life and needed by all organisms. As time goes by, the needs by human increased transforming water quality into bad conditions. Surface water contaminated in various ways which is pointed sources and non-pointed sources. Pointed sources means the source are distinguished from the source such from drains or factory but the non-pointed always occurred in mixed of elements of pollutants. This paper is reviewing the occurrence of the contaminations with effects that occurred around us. Pollutant factors from natural or anthropology factors such nutrients, pathogens, and chemical elements contributed to contaminations. Most of the effects from contaminated surface water contributed to the public health effects also to the environments.

Estimated loads and yields of suspended soils and water-quality constituents in Kentucky streams

USGS Publications Warehouse

Crain, Angela S.

2001-01-01

Loads and yields of suspended solids, nutrients, major ions, trace elements, organic carbon, fecal coliform, dissolved oxygen, and alkalinity were estimated for 22 streams in 11 major river basins in Kentucky. Mean daily discharge was estimated at ungaged stations or stations with incomplete discharge records using drainage-area ratio, regression analysis, or a combination of the two techniques. Streamflow was partitioned into total and base flow and used to estimate loads and yields for suspended solids and water-quality constituents by use of the ESTIMATOR and FLUX computer programs. The relative magnitude of constituent transport to streams from groundand surface-water sources was determined for the 22 stations. Nutrient and suspended solids yields for drainage basins with relatively homogenous land use were used to estimate the total-flow and base-flow yields of nutrient and suspended solids for forested, agricultural, and urban land. Yields of nutrients?nitrite plus nitrate, ammonia plus organic nitrogen, and total phosphorus?in forested drainage basins were generally less than 1 ton per square mile per year ((ton/mi2)/yr) and were generally less than 2 (ton/mi2)/yr in agricultural drainage basins. The smallest total-flow yields for nitrogen (nitrite plus nitrate) was estimated at Levisa Fork at Paintsville in which 95 percent of the land is forested. This site also had one of the smallest total-flow yields for ammonia plus organic nitrogen. In general, nutrient yields from forested lands were lower than those from urban and agricultural land. Some of the largest estimated total-flow yields of nutrients among agricultural basins were for streams in the Licking River Basin, the North Fork Licking River near Milford, and the South Fork Licking River at Cynthiana. Agricultural land constitutes greater than 75 percent of the drainage area in these two basins. Possible sources of nutrients discharging into the Licking River are farm and residential fertilizers. Estimated base-flow yields of suspended solids and nutrients at several basins in the larger Green River and Lower Cumberland River Basins were about half of their estimated total-flow yields. The karst terrain in these basins makes the ground water highly susceptible to contamination, especially if a confining unit is thin or absent.

The English Channel: Contamination status of its transitional and coastal waters.

PubMed

Tappin, A D; Millward, G E

2015-06-30

The chemical contamination (organic compounds, metals, radionuclides, microplastics, nutrients) of English Channel waters has been reviewed, focussing on the sources, concentrations and impacts. River loads were only reliable for Pb, whereas atmospheric loads appeared robust for Cd, Pb, Hg, PCB-153 and γ-HCH. Temporal trends in atmospheric inputs were decreasing. Contaminant concentrations in biota were relatively constant or decreasing, but not for Cd, Hg and HBCDD, and deleterious impacts on fish and copepods were reported. However, data on ecotoxicological effects were generally sparse for legacy and emerging contaminants. Intercomparison of activity concentrations of artificial radionuclides in sediments and biota on both Channel coasts was hindered by differences in methodological approaches. Riverine phosphate loads decreased with time, while nitrate loads remained uniform. Increased biomass of algae, attributable to terrestrial inputs of nutrients, has affected benthic production and shellfisheries. A strategic approach to the identification of contaminant impacts on marine biota is recommended. Copyright © 2014 Elsevier Ltd. All rights reserved.

Increasing floodplain connectivity through urban stream restoration increases nutrient and sediment retention

USGS Publications Warehouse

McMillan, Sara K.; Noe, Gregory

2017-01-01

Stream restoration practices frequently aim to increase connectivity between the stream channel and its floodplain to improve channel stability and enhance water quality through sediment trapping and nutrient retention. To measure the effectiveness of restoration and to understand the drivers of these functional responses, we monitored five restored urban streams that represent a range of channel morphology and restoration ages. High and low elevation floodplain plots were established in triplicate in each stream to capture variation in floodplain connectivity. We measured ecosystem geomorphic and soil attributes, sediment and nutrient loading, and rates of soil nutrient biogeochemistry processes (denitrification; N and P mineralization) then used boosted regression trees (BRT) to identify controls on sedimentation and nutrient processing. Local channel and floodplain morphology and position within the river network controlled connectivity with increased sedimentation at sites downstream of impaired reaches and at floodplain plots near the stream channel and at low elevations. We observed that nitrogen loading (both dissolved and particulate) was positively correlated with denitrification and N mineralization and dissolved phosphate loading positively influenced P mineralization; however, none of these input rates or transformations differed between floodplain elevation categories. Instead, continuous gradients of connectivity were observed rather than categorical shifts between inset and high floodplains. Organic matter and nutrient content in floodplain soils increased with the time since restoration, which highlights the importance of recovery time after construction that is needed for restored systems to increase ecosystem functions. Our results highlight the importance of restoring floodplains downstream of sources of impairment and building them at lower elevations so they flood frequently, not just during bankfull events. This integrated approach has the greatest potential for increasing trapping of sediment, nutrients, and associated pollutants in restored streams and thereby improving water quality in urban watersheds.

Watershed modeling of dissolved oxygen and biochemical oxygen demand using a hydrological simulation Fortran program.

PubMed

Liu, Zhijun; Kieffer, Janna M; Kingery, William L; Huddleston, David H; Hossain, Faisal

2007-11-01

Several inland water bodies in the St. Louis Bay watershed have been identified as being potentially impaired due to low level of dissolved oxygen (DO). In order to calculate the total maximum daily loads (TMDL), a standard watershed model supported by U.S. Environmental Protection Agency, Hydrological Simulation Program Fortran (HSPF), was used to simulate water temperature, DO, and bio-chemical oxygen demand (BOD). Both point and non-point sources of BOD were included in watershed modeling. The developed model was calibrated at two time periods: 1978 to 1986 and 2000 to 2001 with simulated DO closely matched the observed data and captured the seasonal variations. The model represented the general trend and average condition of observed BOD. Water temperature and BOD decay are the major factors that affect DO simulation, whereas nutrient processes, including nitrification, denitrification, and phytoplankton cycle, have slight impacts. The calibrated water quality model provides a representative linkage between the sources of BOD and in-stream DO\\BOD concentrations. The developed input parameters in this research could be extended to similar coastal watersheds for TMDL determination and Best Management Practice (BMP) evaluation.

Modeling nitrogen loading in a small watershed in southwest China using a DNDC model with hydrological enhancements

NASA Astrophysics Data System (ADS)

Deng, J.; Zhou, Z.; Zhu, B.; Zheng, X.; Li, C.; Wang, X.; Jian, Z.

2011-10-01

The degradation of water quality has been observed worldwide, and inputs of nitrogen (N), along with other nutrients, play a key role in the process of contamination. The quantification of N loading from non-point sources at a watershed scale has long been a challenge. Process-based models have been developed to address this problem. Because N loading from non-point sources result from interactions between biogeochemical and hydrological processes, a model framework must include both types of processes if it is to be useful. This paper reports the results of a study in which we integrated two fundamental hydrologic features, the SCS (Soil Conservation Service) curve function and the MUSLE (Modified Universal Soil Loss), into a biogeochemical model, the DNDC. The SCS curve equation and the MUSLE are widely used in hydrological models for calculating surface runoff and soil erosion. Equipped with the new added hydrologic features, DNDC was substantially enhanced with the new capacity of simulating both vertical and horizontal movements of water and N at a watershed scale. A long-term experimental watershed in Southwest China was selected to test the new version of the DNDC. The target watershed's 35.1 ha of territory encompass 19.3 ha of croplands, 11.0 ha of forest lands, 1.1 ha of grassplots, and 3.7 ha of residential areas. An input database containing topographic data, meteorological conditions, soil properties, vegetation information, and management applications was established and linked to the enhanced DNDC. Driven by the input database, the DNDC simulated the surface runoff flow, the subsurface leaching flow, the soil erosion, and the N loadings from the target watershed. The modeled water flow, sediment yield, and N loading from the entire watershed were compared with observations from the watershed and yielded encouraging results. The sources of N loading were identified by using the results of the model. In 2008, the modeled runoff-induced loss of total N from the watershed was 904 kg N yr-1, of which approximately 67 % came from the croplands. The enhanced DNDC model also estimated the watershed-scale N losses (1391 kg N yr-1) from the emissions of the N-containing gases (ammonia, nitrous oxide, nitric oxide, and dinitrogen). Ammonia volatilization (1299 kg N yr-1) dominated the gaseous N losses. The study indicated that process-based biogeochemical models such as the DNDC could contribute more effectively to watershed N loading studies if the hydrological components of the models were appropriately enhanced.

Modeling nitrogen loading in a small watershed in Southwest China using a DNDC model with hydrological enhancements

NASA Astrophysics Data System (ADS)

Deng, J.; Zhou, Z.; Zhu, B.; Zheng, X.; Li, C.; Wang, X.; Jian, Z.

2011-07-01

The degradation of water quality has been observed worldwide, and inputs of nitrogen (N), along with other nutrients, play a key role in the process of contamination. The quantification of N loading from non-point sources at a watershed scale has long been a challenge. Process-based models have been developed to address this problem. Because N loading from non-point sources result from interactions between biogeochemical and hydrological processes, a model framework must include both types of processes if it is to be useful. This paper reports the results of a study in which we integrated two fundamental hydrologic features, the SCS (Soil Conservation Service) curve function and the MUSLE (Modified Universal Soil Loss), into a biogeochemical model, the DNDC. The SCS curve equation and the MUSLE are widely used in hydrological models for calculating surface runoff and soil erosion. Equipped with the new added hydrologic features, DNDC was substantially enhanced with the new capacity of simulating both vertical and horizontal movements of water and N at a watershed scale. A long-term experimental watershed in Southwest China was selected to test the new version of the DNDC. The target watershed's 35.1 ha of territory encompass 19.3 ha of croplands, 11.0 ha of forest lands, 1.1 ha of grassplots, and 3.7 ha of residential areas. An input database containing topographic data, meteorological conditions, soil properties, vegetation information, and management applications was established and linked to the enhanced DNDC. Driven by the input database, the DNDC simulated the surface runoff flow, the subsurface leaching flow, the soil erosion, and the N loadings from the target watershed. The modeled water flow, sediment yield, and N loading from the entire watershed were compared with observations from the watershed and yielded encouraging results. The sources of N loading were identified by using the results of the model. In 2008, the modeled runoff-induced loss of total N from the watershed was 904 kg N yr-1, of which approximately 67 % came from the croplands. The enhanced DNDC model also estimated the watershed-scale N losses (1391 kg N yr-1) from the emissions of the N-containing gases (ammonia, nitrous oxide, nitric oxide, and dinitrogen). Ammonia volatilization (1299 kg N yr-1) dominated the gaseous N losses. The study indicated that process-based biogeochemical models such as the DNDC could contribute more effectively to watershed N loading studies if the hydrological components of the models were appropriately enhanced.

Effects of land use changes on eutrophication indicators in five coastal lagoons of the Southwestern Atlantic Ocean

NASA Astrophysics Data System (ADS)

Rodríguez-Gallego, Lorena; Achkar, Marcel; Defeo, Omar; Vidal, Leticia; Meerhoff, Erika; Conde, Daniel

2017-03-01

Five catchment areas in Uruguay were selected to conduct a nutrient exportation analysis and to evaluate the effects of current land use on the eutrophication of coastal lagoons. Satellite images and national agriculture censuses were used for a quantitative analysis of land use changes from 1974 to 2005, and a nutrient export coefficient approximation was used to determine long-term changes in annual loads. Several eutrophication indicators (water, sediment and autotrophic communities) were assessed seasonally in the lagoon basins during 2005 and 2006. The areal annual load of nutrients exported to the lagoons increased over time. Population and extensive livestock ranching were the most important nutrient sources, while agriculture is increasing in importance. Buffer effects of riparian forests on eutrophication indicators were observed in contrast to the wetlands surrounding the lagoons, which seem to be acting as a source of nutrients. Catchment size was inversely related to most eutrophication indicators. Afforestation and agriculture were found not to directly impact eutrophication indicators, however, catchments with larger agricultural areas showed higher concentrations of suspended solids, which may indicate the export of particulate nutrients. Salinity was inversely related to most eutrophication indicators, suggesting that the manipulation of the sand bar of the lagoons is a critical management issue. Sediment-related eutrophication indicators were more sensitive to changes in land uses and covers, in contrast with the more variable water column indicators, suggesting their potential use as enduring indicators. This research provides a rapid and integral assessment for qualitatively linking catchment changes with eutrophication indicators in coastal environments, which can easily be replicated to track pollutants in locations that lack standardized monitoring programs needed for more complex catchment modeling approaches.

Regional effects of agricultural conservation practices on nutrient transport in the Upper Mississippi River Basin

USGS Publications Warehouse

Garcia, Ana Maria.; Alexander, Richard B.; Arnold, Jeffrey G.; Norfleet, Lee; White, Michael J.; Robertson, Dale M.; Schwarz, Gregory E.

2016-01-01

Despite progress in the implementation of conservation practices, related improvements in water quality have been challenging to measure in larger river systems. In this paper we quantify these downstream effects by applying the empirical U.S. Geological Survey water-quality model SPARROW to investigate whether spatial differences in conservation intensity were statistically correlated with variations in nutrient loads. In contrast to other forms of water quality data analysis, the application of SPARROW controls for confounding factors such as hydrologic variability, multiple sources and environmental processes. A measure of conservation intensity was derived from the USDA-CEAP regional assessment of the Upper Mississippi River and used as an explanatory variable in a model of the Upper Midwest. The spatial pattern of conservation intensity was negatively correlated (p = 0.003) with the total nitrogen loads in streams in the basin. Total phosphorus loads were weakly negatively correlated with conservation (p = 0.25). Regional nitrogen reductions were estimated to range from 5 to 34% and phosphorus reductions from 1 to 10% in major river basins of the Upper Mississippi region. The statistical associations between conservation and nutrient loads are consistent with hydrological and biogeochemical processes such as denitrification. The results provide empirical evidence at the regional scale that conservation practices have had a larger statistically detectable effect on nitrogen than on phosphorus loadings in streams and rivers of the Upper Mississippi Basin.

Regional Effects of Agricultural Conservation Practices on Nutrient Transport in the Upper Mississippi River Basin.

PubMed

García, Ana María; Alexander, Richard B; Arnold, Jeffrey G; Norfleet, Lee; White, Michael J; Robertson, Dale M; Schwarz, Gregory

2016-07-05

Despite progress in the implementation of conservation practices, related improvements in water quality have been challenging to measure in larger river systems. In this paper we quantify these downstream effects by applying the empirical U.S. Geological Survey water-quality model SPARROW to investigate whether spatial differences in conservation intensity were statistically correlated with variations in nutrient loads. In contrast to other forms of water quality data analysis, the application of SPARROW controls for confounding factors such as hydrologic variability, multiple sources and environmental processes. A measure of conservation intensity was derived from the USDA-CEAP regional assessment of the Upper Mississippi River and used as an explanatory variable in a model of the Upper Midwest. The spatial pattern of conservation intensity was negatively correlated (p = 0.003) with the total nitrogen loads in streams in the basin. Total phosphorus loads were weakly negatively correlated with conservation (p = 0.25). Regional nitrogen reductions were estimated to range from 5 to 34% and phosphorus reductions from 1 to 10% in major river basins of the Upper Mississippi region. The statistical associations between conservation and nutrient loads are consistent with hydrological and biogeochemical processes such as denitrification. The results provide empirical evidence at the regional scale that conservation practices have had a larger statistically detectable effect on nitrogen than on phosphorus loadings in streams and rivers of the Upper Mississippi Basin.

Agricultural nutrient loadings to the freshwater environment: the role of climate change and socioeconomic change

NASA Astrophysics Data System (ADS)

Xie, Hua; Ringler, Claudia

2017-10-01

Human activities, in particular agricultural production, interfere with natural cycles of nutrient elements, nitrogen (N) and phosphorus (P), leading to growing concerns about water quality degradation related to excessive nutrient loadings. Increases in agricultural production in response to population growth and wealth generation further increase risks associated with nutrient pollution. This paper presents results from projections of nutrient exports from global agricultural crop and pasture systems to the water environment generated using a process-based modeling approach. Brazil, China, India and the United States account for more than half of estimated global N and P loadings in the base year. Each country boasts large agriculture centers where high calculated loading values are found. Rapid growth in global agricultural nutrient loadings is projected. Growth of agricultural pollution loading is fastest in the group of low-income developing countries and loading growth rates also vary substantially with climate change scenario. Counter measures need to be taken to address the environmental risks associated with the projected rapid increase of agricultural nutrient loadings.

Long-term Changes in Water Quality and Productivity in the Patuxent River Estuary: 1985 to 2003

EPA Science Inventory

We conducted a quantitative assessment of estuarine ecosystem responses to reduced phosphorus and nitrogen loading from sewage treatment facilities and to variability in freshwater flow and non-point nutrient inputs to the Patuxent River estuary. We analyzed a 19-year data set o...

[Estimation of urban non-point source pollution loading and its factor analysis in the Pearl River Delta].

PubMed

Liao, Yi-Shan; Zhuo, Mu-Ning; Li, Ding-Qiang; Guo, Tai-Long

2013-08-01

In the Pearl Delta region, urban rivers have been seriously polluted, and the input of non-point source pollution materials, such as chemical oxygen demand (COD), into rivers cannot be neglected. During 2009-2010, the water qualities at eight different catchments in the Fenjiang River of Foshan city were monitored, and the COD loads for eight rivulet sewages were calculated in respect of different rainfall conditions. Interesting results were concluded in our paper. The rainfall and landuse type played important roles in the COD loading, with greater influence of rainfall than landuse type. Consequently, a COD loading formula was constructed that was defined as a function of runoff and landuse type that were derived SCS model and land use map. Loading of COD could be evaluated and predicted with the constructed formula. The mean simulation accuracy for single rainfall event was 75.51%. Long-term simulation accuracy was better than that of single rainfall. In 2009, the estimated COD loading and its loading intensity were 8 053 t and 339 kg x (hm2 x a)(-1), and the industrial land was regarded as the main source of COD pollution area. The severe non-point source pollution such as COD in Fenjiang River must be paid more attention in the future.

The effect of sampling frequency on the accuracy of nitrogen load estimates from a drained loblolly pine plantation in eastern North Carolina

Treesearch

George M. Chescheir; François Birgand; Shiying Tian; Mohamed A. Youssef; Devendra M. Amatya

2010-01-01

Nutrient loading in drainage outflow is estimated from measured flows and nutrient concentrations in the drainage water. The loading function is ideally continuous, representing the product of continuously measured outflows and nutrient concentrations in drainage water. However, loading is often estimated as the product of continuously measured outflow and nutrient...

Seasonal variation in nutrient retention during inundation of a short-hydroperiod floodplain

USGS Publications Warehouse

Noe, G.B.; Hupp, C.R.

2007-01-01

Floodplains are generally considered to be important locations for nutrient retention or inorganic-to-organic nutrient conversions in riverine ecosystems. However, little is known about nutrient processing in short-hydroperiod floodplains or seasonal variation in floodplain nutrient retention. Therefore, we quantified the net uptake, release or transformation of nitrogen (N), phosphorus (P) and suspended sediment species during brief periods (1-2 days) of overbank flooding through a 250-m floodplain flowpath on the fourth-order Mattawoman Creek, Maryland U.S.A. Sampling occurred during a winter, two spring and a summer flood in this largely forested watershed with low nutrient and sediment loading. Concentrations of NO3- increased significantly in surface water flowing over the floodplain in three of the four floods, suggesting the floodplain was a source of NO3-. The upper portion of the floodplain flowpath consistently exported NH4+, most likely due to the hyporheic: flushing of floodplain soil NH4+, which was then likely nitrified to NO3- in floodwaters. The floodplain was a sink for particulate organic P (POP) during two floods and particulate organic N and inorganic suspended sediment (ISS) during one flood. Large releases of all dissolved inorganic N and P species occurred following a snowmelt and subsequent cold winter flood. Although there was little consistency in most patterns of nutrient processing among the different floods, this floodplain, characterized by brief inundation, low residence time and low nutrient loading, behaved oppositely from the conceptual model for most floodplains in that it generally exported inorganic nutrients and imported organic nutrients.

Cost assessment and ecological effectiveness of nutrient reduction options for mitigating Phaeocystis colony blooms in the Southern North Sea: an integrated modeling approach.

PubMed

Lancelot, Christiane; Thieu, Vincent; Polard, Audrey; Garnier, Josette; Billen, Gilles; Hecq, Walter; Gypens, Nathalie

2011-05-01

Nutrient reduction measures have been already taken by wealthier countries to decrease nutrient loads to coastal waters, in most cases however, prior to having properly assessed their ecological effectiveness and their economic costs. In this paper we describe an original integrated impact assessment methodology to estimate the direct cost and the ecological performance of realistic nutrient reduction options to be applied in the Southern North Sea watershed to decrease eutrophication, visible as Phaeocystis blooms and foam deposits on the beaches. The mathematical tool couples the idealized biogeochemical GIS-based model of the river system (SENEQUE-RIVERSTRAHLER) implemented in the Eastern Channel/Southern North Sea watershed to the biogeochemical MIRO model describing Phaeocystis blooms in the marine domain. Model simulations explore how nutrient reduction options regarding diffuse and/or point sources in the watershed would affect the Phaeocystis colony spreading in the coastal area. The reference and prospective simulations are performed for the year 2000 characterized by mean meteorological conditions, and nutrient reduction scenarios include and compare upgrading of wastewater treatment plants and changes in agricultural practices including an idealized shift towards organic farming. A direct cost assessment is performed for each realistic nutrient reduction scenario. Further the reduction obtained for Phaeocystis blooms is assessed by comparison with ecological indicators (bloom magnitude and duration) and the cost for reducing foam events on the beaches is estimated. Uncertainty brought by the added effect of meteorological conditions (rainfall) on coastal eutrophication is discussed. It is concluded that the reduction obtained by implementing realistic environmental measures on the short-term is costly and insufficient to restore well-balanced nutrient conditions in the coastal area while the replacement of conventional agriculture by organic farming might be an option to consider in the nearby future. Copyright © 2011 Elsevier B.V. All rights reserved.

Magnitudes, nature, and effects of point and nonpoint discharges in the Chattahoochee River Basin, Atlanta to West Point Dam, Georgia

USGS Publications Warehouse

Stamer, J.K.; Cherry, Rodney N.; Faye, R.E.; Kleckner, R.L.

1979-01-01

During the period April 1975 to June 1978, the U.S. Geological Survey conducted a river-quality assessment of the Upper Chattahoochee River basin in Georgia. One objective of the study was to assess the magnitudes, nature, and effects of point and non-point discharges in the Chattahoochee River basin from Atlanta to the West Point Dam. On an average annual basis and during the storm period of March 1215, 1976, non-point-source loads for most constituents analyzed were larger than point-source loads at the Whitesburg station, located on the Chattahoochee River about 40 river miles downstream of Atlanta. Most of the non-point-source constituent loads in the Atlanta-to-Whitesburg reach were from urban areas. Average annual point-source discharges accounted for about 50 percent of the dissolved nitrogen, total nitrogen, and total phosphorus loads, and about 70 percent of the dissolved phosphorus loads at Whitesburg. During weekends, power generation at the upstream Buford Dam hydroelectric facility is minimal. Streamflow at the Atlanta station during dry-weather weekends is estimated to be about 1,200 ft3/s (cubic feet per second). Average daily dissolved-oxygen concentrations of less than 5.0 mg/L (milligrams per liter) occurred often in the river, about 20 river miles downstream from Atlanta during these periods from May to November. During a low-flow period, June 1-2, 1977, five municipal point sources contributed 63 percent of the ultimate biochemical oxygen demand, 97 percent of the ammonium nitrogen, 78 percent of the total nitrogen, and 90 percent of the total phosphorus loads at the Franklin station, at the upstream end of West Point Lake. Average daily concentrations of 13 mg/L of ultimate biochemical oxygen demand and 1.8 mg/L of ammonium nitrogen were observed about 2 river miles downstream from two of the municipal point sources. Carbonaceous and nitrogenous oxygen demands caused dissolved-oxygen concentrations between 4.1 and 5.0 mg/L to occur in a 22-mile reach of the river downstream from Atlanta. Nitrogenous oxygen demands were greater than carbonaceous oxygen demands in the reach from river mile 303 to 271, and carbonaceous demands were greater from river mile 271 to 235. The heat load from the Atkinson-McDonough thermoelectric power-plants caused a decrease in the dissolved-oxygen concentrations of about 0.2 mg/L. During a critical low-flow period, a streamflow at Atlanta of about 1,800 ft3/s, with present (1977) point-source flows of 185 ft3/s containing concentrations of 45 mg/L of ultimate biochemical oxygen demand and 15 mg/L of ammonium nitrogen, results in a computed minimum dissolved-oxygen concentration of 4.7 mg/L in the river downstream from Atlanta. In the year 2000, a streamflow at Atlanta of about 1,800 ft3/s with point-source flows of 373 ft3/s containing concentrations of 45 mg/L of ultimate biochemical oxygen demand and 5.0 mg/L of ammonium nitrogen, will result in a computed minimum dissolved-oxygen concentration of 5.0 mg/L. A streamflow of about 1,050 ft3/s at Atlanta in the year 2000 will result in a dissolved-oxygen concentration of 5.0 mg/L if point-source flows contain concentrations of 15 mg/L of ultimate biochemical oxygen demand and 5.0 mg/L of ammonium nitrogen. Phytoplankton concentrations in West Point Lake, about 70 river miles downstream from Atlanta, could exceed 3 million cells per milliliter during extended low-flow periods in the summer with present point- and non-point-source nitrogen and phosphorus loads. In the year 2000, phytoplankton concentrations in West Point Lake are not likely to exceed 700,000 cells per milliliter during extended low-flow periods in the summer, if phosphorus concentrations do not exceed 1.0 mg/L in point-source discharges.

An investigation of submarine groundwater-borne nutrient fluxes to the west Florida shelf and recurrent harmful algal blooms

USGS Publications Warehouse

Smith, Christopher G.; Swarzenski, Peter W.

2012-01-01

A cross-shelf, water-column mass balance of radon-222 (222Rn) provided estimates of submarine groundwater discharge (SGD), which were then used to quantify benthic nutrient fluxes. Surface water and groundwater were collected along a shore-normal transect that extended from Tampa Bay, Florida, across the Pinellas County peninsula, to the 10-m isobath in the Gulf of Mexico. Samples were analyzed for 222Rn and radium-223,224,226 (223,224,226Ra) activities as well as inorganic and organic nutrients. Cross-shore gradients of 222Rn and 223,224,226Ra activities indicate a nearshore source for these isotopes, which mixes with water characterized by low activities offshore. Radon-based SGD rates vary between 2.5 and 15 cm d-1 proximal to the shoreline and decrease offshore. The source of SGD is largely shallow exchange between surface and pore waters, although deeper groundwater cycling may also be important. Enrichment of total dissolved nitrogen and soluble reactive phosphorus in pore water combined with SGD rates results in specific nutrient fluxes comparable to or greater than estuarine fluxes from Tampa Bay. The significance of these fluxes to nearshore blooms of Karenia brevis is highlighted by comparison with prescribed nutrient demands for bloom maintenance and growth. Whereas our flux estimates do not indicate SGD and benthic fluxes as the dominant nutrient source to the harmful algal blooms, SGD-derived loads do narrow the deficit between documented nutrient supplies and bloom demands.

Quantifying Groundwater Nutrient Discharge to a Large Glacial Lake using a Watershed Loading Model

NASA Astrophysics Data System (ADS)

Schilling, K. E.

2015-12-01

Groundwater discharge to a lake is an important, if often neglected, component to water and nutrient budgets. Point measurements of groundwater discharge into a lake are prone to error, so in this study of 15.57 km2 West Lake Okoboji, Iowa, a watershed-based groundwater loading model was developed. Located in northwest Iowa, West Lake Okoboji is considered one of Iowa's premier tourist destinations but is threatened by eutrophication. A network of 21 observation wells was installed in the watershed to evaluate groundwater recharge and quality under representative land cover types in a range of landscape positions. Our objective was to develop typical groundwater responses from various land cover-landscape associations for scaling up to unmonitored areas in the watershed. Results indicated substantial variation in groundwater recharge and quality in the 3847 ha watershed. Recharge was similar among land covers under vegetation but was much lower under urban pavement. Nitrate-nitrogen concentrations were highest under cropped fields and lowest under perennial grassland and golf courses, whereas dissolved phosphorus was highest under residential and urban areas, including an engineered bioswale. A groundwater load allocation model indicated 91% of the nitrate load was from cropped areas and 7% from residential areas. In contrast, P loads were more equally divided among cropped fields (43%), perennial grass (36%) and residential (19%) areas. Based on the mass of nitrate and P in the lake, groundwater accounts for 71% and 18% of the nutrient inputs, respectively.

Groundwater nutrient concentrations near an incised midwestern stream: Effects of floodplain lithology and land management

USGS Publications Warehouse

Schilling, K.E.; Jacobson, P.

2008-01-01

It has been recognized that subsurface lithology plays an important role in controlling nutrient cycling and transport in riparian zones. In Iowa and adjacent states, the majority of alluvium preserved in small and moderate sized valleys consists of Holocene-age organic-rich, and fine-grained loam. In this paper, we describe and evaluate spatial and temporal patterns of lithology and groundwater nutrient concentrations at a riparian well transect across Walnut Creek at the Neal Smith National Wildlife Refuge in Jasper County, Iowa. Land treatment on one side of the stream reduced the grass cover to bare ground and allowed assessment of the effects of land management on nutrient concentrations. Results indicated that groundwater in Holocene alluvium is very nutrient rich with background concentrations of nitrogen, phosphorus and dissolved organic carbon that exceed many environmentally sensitive criteria. Average concentrations of ammonium exceeded 1 mg/l in several wells under grass cover whereas nitrate concentrations exceeded 20 mg/l in wells under bare ground. Phosphate concentrations ranged from 0.1 to 1.3 mg/l and DOC concentrations exceeded 5 mg/l in many wells. Denitrification, channel incision, land management and geologic age of alluvium were found to contribute to variable nutrient loading patterns at the site. Study results indicated that riparian zones of incised streams downcutting through nutrient-rich Holocene alluvium can potentially be a significant source of nutrient loadings to streams. ?? 2008 Springer Science+Business Media B.V.

The effect of nitrogen loading on on-site system design: a model for determining land application area size.

PubMed

McCardell, A; Davison, L; Edwards, A

2005-01-01

Designers of on-site wastewater management systems have six opportunities to remove pollutants of concern from the aqueous waste stream before it reaches ground or surface waters. These opportunities occur at source, at point of collection (primary treatment), secondary treatment, tertiary treatment, land application and buffers. This paper presents a computer based model for the sizing of on-site system land application areas applicable to the Lismore area in Northern New South Wales, a region of high rainfall. Inputs to the model include daily climatic data, soil type, number of people loading the system and size of housing allotment. Constraints include allowable phosphorus export, nitrogen export and hydraulic percolation. In the Lismore area nitrogen is the nutrient of most concern. In areas close to environmentally sensitive waterways, and in dense developments, the allowable annual nitrogen export becomes the main factor determining the land application area size. The model offers system designers the opportunity to test various combinations of nitrogen attenuation strategies (source control, secondary treatment) in order to create a solution which offers an acceptable nitrogen export rate while meeting the client's household and financial needs. The model runs on an Excel spreadsheet and has been developed by Lismore City Council.

[Research on land use structure optimization based on nonpoint source dissolved nitrogen load estimation in Shuaishui watershed].

PubMed

Lu, Yu-Chao; Bi, Meng-Fei; Li, Ze-Li; Sha, Jian; Wang, Yu-Qiu; Qian, Li-Ping

2014-06-01

Regional Nutrient Management (ReNuMa) was applied to estimate dissolved nitrogen (DN) load and perform source apportionment in Shuaishui watershed during 2000-2010. Satisfactory performance of ReNuMa was revealed by the E(ns) and R2 of greater than 0.9 in calibrating and validating streamflow and DN. The average nonpoint DN load in this watershed was 1.11 x 10(3) t x a(-1), with the load intensity of (0.75 +/- 0.22) t x km(-2). Among all the land uses, paddy field had the largest DN load intensity [28.60 kg x (hm2 x a)(-1)], while forest had the least [2.71 kg x (hm2 x a)(-1)]. Agricultural land (including paddy, grain, cash crop, tea plant and orchard) contributed most to DN load in Shuaishui watershed, indicating that the human dominated agricultural activities was the major contributor of nonpoint source pollution. Land use structure optimization for Shuaishui watershed in 2015 was conducted under the rule of reducing pollutants loads and maximizing the agricultural output value. The results demonstrated that agricultural monetary growth was accompanied with the increasing DN load at the optimal level, although output increment was higher than that of DN load.

Nutrient loads in the river mouth of the Río Verde basin in Jalisco, Mexico: how to prevent eutrophication in the future reservoir?

PubMed

Jayme-Torres, Gonzalo; Hansen, Anne M

2017-10-04

Since nutrients are emitted and mobilized in river basins, causing eutrophication of water bodies, it is important to reduce such emissions and subsequent nutrient loads. Due to processes of attenuation, nutrient loads are reduced during their mobilization in river basins. At the mouth of the Río Verde basin in western Mexico, the El Purgatorio dam is being constructed to supply water to the metropolitan area of the second most populated city in the country, Guadalajara. To analyze situations that allow protecting this future dam from eutrophication, nutrient loads in the mouth of the river basin were determined and their reduction scenarios evaluated by using the NEWS2 (Nutrient Export from Watersheds) model. For this, a nutrient emissions inventory was established and used to model nutrient loads, and modeling results were compared to an analysis of water quality data from two different monitoring sites located on the river. The results suggest that 96% of nitrogen and 99% of phosphorus emissions are attenuated in the watershed. Nutrient loads reaching the mouth of the river basin come mainly from wastewater discharges, followed by livestock activities and different land uses, and loads are higher as emissions are located closer to the mouth of the river basin. To achieve and maintain mesotrophic state of water in the future dam, different nutrient emission reduction scenarios were evaluated. According to these results, the reduction of 90% of the phosphorus loads in wastewater emissions or 75% of the phosphorus loads in wastewater emissions and at least 50% in emissions from livestock activities in the river basin are required.

Data Used in Analyses of Trends, and Nutrient and Suspended-Sediment Loads for Streams in the Southeastern United States, 1973-2005

USGS Publications Warehouse

Staub, Erik L.; Peak, Kelly L.; Tighe, Kirsten C.; Sadorf, Eric M.; Harned, Douglas A.

2010-01-01

Water-quality data from selected surface-water monitoring sites in the Southeastern United States were assessed for trends in concentrations of nutrients, suspended sediment, and major constituents and for in-stream nutrient and suspended-sediment loads for the period 1973-2005. The area of interest includes river basins draining into the southern Atlantic Ocean, the Gulf of Mexico, and the Tennessee River-drainage basins in Hydrologic Regions 03 (South Atlantic - Gulf) and 06 (Tennessee). This data assessment is related to studies of several major river basins as part of the U.S. Geological Survey National Water-Quality Assessment Program, which was designed to assess national water-quality trends during a common time period (1993-2004). Included in this report are data on which trend tests could be performed from 44 U.S. Geological Survey National Water Information System (NWIS) sampling sites. The constituents examined include major ions, nutrients, and suspended sediment; the physical properties examined include pH, specific conductance, dissolved oxygen, and streamflow. Also included are data that were tested for trends from an additional 290 sites from the U.S. Environmental Protection Agency Storage and Retrieval (STORET) database. The trend analyses of the STORET data were limited to total nitrogen and total phosphorus concentrations. Data from 48 U.S. Geological Survey NWIS sampling sites with sufficient water-quality and continuous streamflow data for estimating nutrient and sediment loads are included. The methods of data compilation and modification used prior to performing trend tests and load estimation are described. Results of the seasonal Kendall trend test and the Tobit trend test are given for the 334 monitoring sites, and in-stream load estimates are given for the 48 monitoring sites. Basin characteristics are provided, including regional landscape variables and agricultural nutrient sources (annual variations in cropping and fertilizer use). The data and results presented in this report are in tabular format and can be downloaded and used by environmental researchers and water managers, particularly in the Southeast.

Combining Water Quality and Cost-Benefit Analysis to Examine the Implications of Agricultural Best Management Practices

NASA Astrophysics Data System (ADS)

Rao, N. S.; Easton, Z. M.; Lee, D. R.; Steenhuis, T. S.

2007-12-01

Nutrient runoff from agricultural fields threatens water quality and can impair habitats in many watersheds. Agencies consider these potential risks as they determine acceptable levels of nutrient loading. For example, in the New York City (NYC) watershed, the Environmental Protection Agency's Total Maximum Daily Load (TMDL) for phosphorus (P) has been set at 15μg P L-1 to protect against eutrophication and bacterial outbreaks. In the NYC watersheds agricultural Best Management Practices (BMPs) are the primary means to control nonpoint source P loading. BMPs include riparian buffers, filter strips, manure storage facilities, crop rotation, stripcropping, tree planting and nutrient management plans (NMPs). Water quality research on BMPs to date has included studies on site-specificity of different BMPs, short and long term BMP efficacy, and placement of BMPs with respect to critical source areas. A necessary complement to studies addressing water quality aspects of different BMPs are studies examining the cost-benefit aspects of BMPs. In general, there are installment, maintenance and opportunity costs associated with each BMP, and there are benefits, including cost share agreements between farmers and farm agencies, and increased efficiency of farm production and maintenance. Combining water quality studies and related cost-benefit analyses would help planners and watershed managers determine how best improve water quality. Our research examines the costs-benefit structure associated with BMP scenarios on a one-farm headwater watershed in the Catskill Mountains of NY. The different scenarios include "with and without" BMPs, combinations of BMPs, and different BMP placements across agricultural fields. The costs associated with each BMP scenarios are determined using information from farm agencies and watershed planning agencies. With these data we perform a cost-benefit analysis for the different BMP scenarios and couple the water quality modeling using the Variable Source Loading Function (VSLF) model (Schneiderman et al., 2007) with the cost-benefit analysis to look at the specific water quality and economic consequences of different watershed management scenarios. The results of our study will be useful for planners and watershed managers in determining how best to reduce nonpoint source pollution in a cost-effective manner. References Schneiderman, E.M., T.S. Steenhuis, D.J. Thongs, Z.M. Easton, M.S. Zion, G.F. Mendoza, M.T. Walter, and A.C. Neal. 2007. Incorporating variable source area hydrology into curve number based watershed loading functions. Hydrol. Proc. (In Press).

Hot moments and hot spots of nutrient losses from a mixed land use watershed

USDA-ARS?s Scientific Manuscript database

Non-point nitrogen (N) and phosphorus (P) pollution from agriculture has increasingly received more public attention. However, when, where and how N and P export occurs from a watershed is not completely understood. In this study, nitrate-N, dissolved P and particulate P concentrations and loads wer...

Identifying sources of nitrogen to Hanalei Bay, Kauai, utilizing the nitrogen isotope signature of macroalgae

USGS Publications Warehouse

Derse, E.; Knee, K.L.; Wankel, Scott D.; Kendall, C.; Berg, C.J.; Paytan, A.

2007-01-01

Sewage effluent, storm runoff, discharge from polluted rivers, and inputs of groundwater have all been suggested as potential sources of land derived nutrients into Hanalei Bay, Kauai. We determined the nitrogen isotopic signatures (??15N) of different nitrate sources to Hanalei Bay along with the isotopic signature recorded by 11 species of macroalgal collected in the Bay. The macroalgae integrate the isotopic signatures of the nitrate sources over time, thus these data along with the nitrate to dissolved inorganic phosphate molar ratios (N:P) of the macroalgae were used to determine the major nitrate source to the bay ecosystem and which of the macro-nutrients is limiting algae growth, respectively. Relatively low ??15N values (average -0.5???) were observed in all algae collected throughout the Bay; implicating fertilizer, rather than domestic sewage, as an important external source of nitrogen to the coastal water around Hanalei. The N:P ratio in the algae compared to the ratio in the Bay waters imply that the Hanalei Bay coastal ecosystem is nitrogen limited and thus, increased nitrogen input may potentially impactthis coastal ecosystem and specifically the coral reefs in the Bay. Identifying the major source of nutrient loading to the Bay is important for risk assessment and potential remediation plans. ?? 2007 American Chemical Society.

4R Water Quality Impacts: An Assessment and Synthesis of Forty Years of Drainage Nitrogen Losses.

PubMed

Christianson, L E; Harmel, R D

2015-11-01

The intersection of agricultural drainage and nutrient mobility in the environment has led to multiscale water quality concerns. This work reviewed and quantitatively analyzed nearly 1,000 site-years of subsurface tile drainage nitrogen (N) load data to develop a more comprehensive understanding of the impacts of 4R practices (application of the right source of nutrients, at the right rate and time, and in the right place) within drained landscapes across North America. Using drainage data newly compiled in the "Measured Annual Nutrient loads from AGricultural Environments" (MANAGE) database, relationships were developed across N application rates for nitrate N drainage loads and corn ( L.) yields. The lack of significant differences between N application timing or application method was inconsistent with the current emphasis placed on application timing, in particular, as a water quality improvement strategy ( = 0.934 and 0.916, respectively). Broad-scale analyses such as this can help identify major trends for water quality, but accurate implementation of the 4R approach will require site-specific knowledge to balance agronomic and environmental goals. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Non-Point Source Pollutant Load Variation in Rapid Urbanization Areas by Remote Sensing, Gis and the L-THIA Model: A Case in Bao'an District, Shenzhen, China.

PubMed

Li, Tianhong; Bai, Fengjiao; Han, Peng; Zhang, Yuanyan

2016-11-01

Urban sprawl is a major driving force that alters local and regional hydrology and increases non-point source pollution. Using the Bao'an District in Shenzhen, China, a typical rapid urbanization area, as the study area and land-use change maps from 1988 to 2014 that were obtained by remote sensing, the contributions of different land-use types to NPS pollutant production were assessed with a localized long-term hydrologic impact assessment (L-THIA) model. The results show that the non-point source pollution load changed significantly both in terms of magnitude and spatial distribution. The loads of chemical oxygen demand, total suspended substances, total nitrogen and total phosphorus were affected by the interactions between event mean concentration and the magnitude of changes in land-use acreages and the spatial distribution. From 1988 to 2014, the loads of chemical oxygen demand, suspended substances and total phosphorus showed clearly increasing trends with rates of 132.48 %, 32.52 % and 38.76 %, respectively, while the load of total nitrogen decreased by 71.52 %. The immigrant population ratio was selected as an indicator to represent the level of rapid urbanization and industrialization in the study area, and a comparison analysis of the indicator with the four non-point source loads demonstrated that the chemical oxygen demand, total phosphorus and total nitrogen loads are linearly related to the immigrant population ratio. The results provide useful information for environmental improvement and city management in the study area.

Non-Point Source Pollutant Load Variation in Rapid Urbanization Areas by Remote Sensing, Gis and the L-THIA Model: A Case in Bao'an District, Shenzhen, China

NASA Astrophysics Data System (ADS)

Li, Tianhong; Bai, Fengjiao; Han, Peng; Zhang, Yuanyan

2016-11-01

Urban sprawl is a major driving force that alters local and regional hydrology and increases non-point source pollution. Using the Bao'an District in Shenzhen, China, a typical rapid urbanization area, as the study area and land-use change maps from 1988 to 2014 that were obtained by remote sensing, the contributions of different land-use types to NPS pollutant production were assessed with a localized long-term hydrologic impact assessment (L-THIA) model. The results show that the non-point source pollution load changed significantly both in terms of magnitude and spatial distribution. The loads of chemical oxygen demand, total suspended substances, total nitrogen and total phosphorus were affected by the interactions between event mean concentration and the magnitude of changes in land-use acreages and the spatial distribution. From 1988 to 2014, the loads of chemical oxygen demand, suspended substances and total phosphorus showed clearly increasing trends with rates of 132.48 %, 32.52 % and 38.76 %, respectively, while the load of total nitrogen decreased by 71.52 %. The immigrant population ratio was selected as an indicator to represent the level of rapid urbanization and industrialization in the study area, and a comparison analysis of the indicator with the four non-point source loads demonstrated that the chemical oxygen demand, total phosphorus and total nitrogen loads are linearly related to the immigrant population ratio. The results provide useful information for environmental improvement and city management in the study area.

THE DETROIT RIVER AS A CHEMICAL LOADING SOURCE TO LAKE ERIE

EPA Science Inventory

The Detroit River, one of 42 designated areas of concern., has been classified as one of the most polluted rivers in North America. This system receives chemical loadings from a variety of sources including upstream discharges, industrial/municipal point sources, combined sewage ...

Estimation of Shallow Groundwater Discharge and Nutrient Load into a River

Treesearch

Ying Ouyang

2012-01-01

Pollution of rivers with excess nutrients due to groundwater discharge, storm water runoff, surface loading,and atmospheric deposition is an increasing environmental concern worldwide. While the storm water runoff and surface loading of nutrients into many rivers have been explored in great detailed, the groundwater discharge of nutrients into the rivers has not yet...

Predicting the Impacts of Climate Change on Runoff and Sediment Processes in Agricultural Watersheds: A Case Study from the Sunflower Watershed in the Lower Mississippi Basin

NASA Astrophysics Data System (ADS)

Elkadiri, R.; Momm, H.; Yasarer, L.; Armour, G. L.

2017-12-01

Climatic conditions play a major role in physical processes impacting soil and agrochemicals detachment and transportation from/in agricultural watersheds. In addition, these climatic conditions are projected to significantly vary spatially and temporally in the 21st century, leading to vast uncertainties about the future of sediment and non-point source pollution transport in agricultural watersheds. In this study, we selected the sunflower basin in the lower Mississippi River basin, USA to contribute in the understanding of how climate change affects watershed processes and the transport of pollutant loads. The climate projections used in this study were retrieved from the archive of World Climate Research Programme's (WCRP) Coupled Model Intercomparison Phase 5 (CMIP5) project. The CMIP5 dataset was selected because it contains the most up-to-date spatially downscaled and bias corrected climate projections. A subset of ten GCMs representing a range in projected climate were spatially downscaled for the sunflower watershed. Statistics derived from downscaled GCM output representing the 2011-2040, 2041-2070 and 2071-2100 time periods were used to generate maximum/minimum temperature and precipitation on a daily time step using the USDA Synthetic Weather Generator, SYNTOR. These downscaled climate data were then utilized as inputs to run in the Annualized Agricultural Non-Point Source (AnnAGNPS) pollution watershed model to estimate time series of runoff, sediment, and nutrient loads produced from the watershed. For baseline conditions a validated simulation of the watershed was created and validated using historical data from 2000 until 2015.

Groundwater-derived nutrient inputs to the Upper Gulf of Thailand

NASA Astrophysics Data System (ADS)

Burnett, William C.; Wattayakorn, Gullaya; Taniguchi, Makoto; Dulaiova, Henrieta; Sojisuporn, Pramot; Rungsupa, Sompop; Ishitobi, Tomotoshi

2007-01-01

We report here the first direct measurements of nutrient fluxes via groundwater discharge into the Upper Gulf of Thailand. Nutrient and standard oceanographic surveys were conducted during the wet and dry seasons along the Chao Phraya River, Estuary and out into the Upper Gulf of Thailand. Additional measurements in selected near-shore regions of the Gulf included manual and automatic seepage meter deployments, as well as nutrient evaluations of seepage and coastal waters. The river transects characterized the distribution of biogeochemical parameters in this highly contaminated urban environment. Seepage flux measurements together with nutrient analyses of seepage fluids were used to estimate nutrient fluxes via groundwater pathways for comparison to riverine fluxes. Our findings show that disseminated seepage of nutrient-rich mostly saline groundwater into the Upper Gulf of Thailand is significant. Estimated fluxes of dissolved inorganic nitrogen (DIN) supplied via groundwater discharge were 40-50% of that delivered by the Chao Phraya River, inorganic phosphate was 60-70%, and silica was 15-40%. Dissolved organic nitrogen (DON) and phosphorus (DOP) groundwater fluxes were also high at 30-40% and 30-130% of the river inputs, respectively. These observations are especially impressive since the comparison is being made to the river that is the largest source of fresh water into the Gulf of Thailand and flows directly through the megacity of Bangkok with high nutrient loadings from industrial and domestic sources.

Discrete Organic Phosphorus Signatures are Evident in Pollutant Sources within a Lake Erie Tributary.

PubMed

Brooker, M R; Longnecker, K; Kujawinski, E B; Evert, M H; Mouser, P J

2018-06-19

Phosphorus loads are strongly associated with the severity of harmful algal blooms in Lake Erie, a Great Lake situated between the United States and Canada. Inorganic and total phosphorus measurements have historically been used to estimate nonpoint and point source contributions, from contributing watersheds with organic phosphorus often neglected. Here, we used ultrahigh resolution mass spectrometry to characterize the dissolved organic matter and specifically dissolved organic phosphorus composition of several nutrient pollutant source materials and aqueous samples in a Lake Erie tributary. We detected between 23 and 313 organic phosphorus formulas across our samples, with manure samples having greater abundance of phosphorus- and nitrogen containing compounds compared to other samples. Manures also were enriched in lipids and protein-like compounds. The greatest similarities were observed between the Sandusky River and wastewater treatment plant effluent (WWTP), or the Sandusky River and agricultural edge of field samples. These sample pairs shared 84% of organic compounds and 59-73% of P-containing organic compounds, respectively. This similarity suggests that agricultural and/or WWTP sources dominate the supply of organic phosphorus compounds to the river. We identify formulas shared between the river and pollutant sources that could serve as possible markers of source contamination in the tributary.

Climate change impacts on the nutrient losses of two watersheds in the Great Lakes region

USDA-ARS?s Scientific Manuscript database

Non-point sources (NPS) of agricultural chemical pollution are one major reason for the degradation of water quality in the Great Lakes. This study focuses on quantifying the impacts of climate change on nutrient (Nitrogen and Phosphorus) losses from NPS in the Great Lakes region through the end of ...

Evaluation of a Leaf Collection and Street Cleaning Program as a Way to Reduce Nutrients and Organic Carbon in Urban Runoff

NASA Astrophysics Data System (ADS)

Selbig, W.

2016-12-01

Organic detritus can be major sources of nutrients and organic carbon in urban stormwater, especially in areas with dense overhead tree canopy. In order to meet impending regulation to reduce nutrient loads, many cities will require information on structural and non-structural stormwater control measures that target organic detritus. Most cities already conduct some level of leaf collection and existing street cleaning programs; however, few studies have quantified their water-quality benefits. The U.S Geological Survey measured the water-quality benefits of a municipal leaf collection program coupled with street cleaning in Madison, WI, USA during the months of October through November of 2014 and 2015. The calibration phase of the study (2014) characterized nutrient and organic carbon concentrations and loads in runoff from two paired basins without leaf collection or street cleaning. During the treatment phase (2015), leaf collection and street cleaning was done in the test basin by city personnel on a weekly basis. Additionally, prior to each precipitation event, USGS personnel removed as much organic debris from the street surface as reasonably possible. The control remained without street cleaning or leaf collection for the entire monitoring period. During the fall, leaf collection and street cleaning was able to remove the increased amount of organic debris from the curb and street surface which resulted in statistically significant (p<0.05) reductions in loads of phosphorus, nitrogen and organic carbon. Total and dissolved phosphorus loads were reduced by 84 and 83 percent, respectively. Similarly, total and dissolved organic carbon was reduced by 81 and 86 percent, and total and dissolved nitrogen was reduced by 74 and 71 percent, respectively. In the control basin, 60 percent of the annual phosphorus load occurred in fall (winter excluded), the majority of which was dissolved as orthophosphorus, compared to only 16 percent in the test basin. While the leaf collection practices adopted during this study may surpass those used by most municipal programs, results from this study suggest a significant reduction of nutrient and organic carbon loads in urban stormwater is feasible when leaves and other organic detritus are removed from streets prior to precipitation events.

Effects of wildfire on source-water quality and aquatic ecosystems, Colorado Front Range

USGS Publications Warehouse

Writer, Jeffrey H.; McCleskey, R. Blaine; Murphy, Sheila F.; Stone, Mike; Collins, Adrian; Thoms, Martin C.

2012-01-01

Watershed erosion can dramatically increase after wildfire, but limited research has evaluated the corresponding influence on source-water quality. This study evaluated the effects of the Fourmile Canyon wildfire (Colorado Front Range, USA) on source-water quality and aquatic ecosystems using high- frequency sampling. Dissolved organic carbon (DOC) and nutrient loads in stream water were evaluated for a one-year period during different types of runoff events, including spring snowmelt, and both frontal and summer convective storms. DOC export from the burned watershed did not increase relative to the unburned watershed during spring snowmelt, but substantial increases in DOC export were observed during summer convective storms. Elevated nutrient export from the burned watershed was observed during spring snowmelt and summer convective storms, which increased the primary productivity of stream biofilms. Wildfire effects on source-water quality were shown to be substantial following high-intensity storms, with the potential to affect drinking-water treatment processes.

A national assessment of the effect of intensive agro-land use practices on nonpoint source pollution using emission scenarios and geo-spatial data.

PubMed

Zhuo, Dong; Liu, Liming; Yu, Huirong; Yuan, Chengcheng

2018-01-01

China's intensive agriculture has led to a broad range of adverse impacts upon ecosystems and thereby caused environmental quality degradation. One of the fundamental problems that face land managers when dealing with agricultural nonpoint source (NPS) pollution is to quantitatively assess the NPS pollution loads from different sources at a national scale. In this study, export scenarios and geo-spatial data were used to calculate the agricultural NPS pollution loads of nutrient, pesticide, plastic film residue, and crop straw burning in China. The results provided the comprehensive and baseline knowledge of agricultural NPS pollution from China's arable farming system in 2014. First, the nitrogen (N) and phosphorus (P) emission loads to water environment were estimated to be 1.44 Tg N and 0.06 Tg P, respectively. East and south China showed the highest load intensities of nutrient release to aquatic system. Second, the amount of pesticide loss to water of seven pesticides that are widely used in China was estimated to be 30.04 tons (active ingredient (ai)). Acetochlor was the major source of pesticide loss to water, contributing 77.65% to the total loss. The environmental impacts of pesticide usage in east and south China were higher than other parts. Third, 19.75% of the plastic film application resided in arable soils. It contributed a lot to soil phthalate ester (PAE) contamination. Fourth, 14.11% of straw produce were burnt in situ, most occurring in May to July (post-winter wheat harvest) in North China Plain and October to November (post-rice harvest days) in southeast China. All the above agricultural NPS pollution loadings were unevenly distributed across China. The spatial correlations between pollution loads at land unit scale were also estimated. Rising labor cost in rural China might be a possible explanation for the general positive correlations of the NPS pollution loads. It also indicated a co-occurred higher NPS pollution loads and a higher human exposure risk in eastern regions. Results from this research might provide full-scale information on the status and spatial variation of various agricultural NPS pollution loads for policy makers to control the NPS pollution in China.

Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia.

PubMed

van der Wulp, Simon A; Damar, Ario; Ladwig, Norbert; Hesse, Karl-J

2016-09-30

The present application of numerical modelling techniques provides an overview of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay. A hydrological model simulated river discharges with a total of 90 to 377m(3)s(-1) entering Jakarta Bay. Daily total nitrogen and total phosphorus loads ranged from 40 to 174tons and 14 to 60tons, respectively. Flow model results indicate that nutrient gradients are subject to turbulent mixing by tides and advective transport through circulation driven by wind, barotropic and baroclinic pressure gradients. The bulk of nutrient loads originate from the Citarum and Cisadane rivers flowing through predominantly rural areas. Despite lower nutrient loads, river discharges from the urban area of Jakarta exhibit the highest impact of nutrient concentrations in the near shore area of Jakarta Bay and show that nutrient concentrations were not only regulated by nutrient loads but were strongly regulated by initial river concentrations and local flow characteristics. Copyright © 2016 Elsevier Ltd. All rights reserved.

A pollutant load hierarchical allocation method integrated in an environmental capacity management system for Zhushan Bay, Taihu Lake.

PubMed

Liang, Shidong; Jia, Haifeng; Yang, Cong; Melching, Charles; Yuan, Yongping

2015-11-15

An environmental capacity management (ECM) system was developed to help practically implement a Total Maximum Daily Load (TMDL) for a key bay in a highly eutrophic lake in China. The ECM system consists of a simulation platform for pollutant load calculation and a pollutant load hierarchical allocation (PLHA) system. The simulation platform was developed by linking the Environmental Fluid Dynamics Code (EFDC) and Water Quality Analysis Simulation Program (WASP). In the PLHA, pollutant loads were allocated top-down in several levels based on characteristics of the pollutant sources. Different allocation methods could be used for the different levels with the advantages of each method combined over the entire allocation. Zhushan Bay of Taihu Lake, one of the most eutrophic lakes in China, was selected as a case study. The allowable loads of total nitrogen, total phosphorus, ammonia, and chemical oxygen demand were found to be 2122.2, 94.9, 1230.4, and 5260.0 t·yr(-1), respectively. The PLHA for the case study consists of 5 levels. At level 0, loads are allocated to those from the lakeshore direct drainage, atmospheric deposition, internal release, and tributary inflows. At level 1 the loads allocated to tributary inflows are allocated to the 3 tributaries. At level 2, the loads allocated to one inflow tributary are allocated to upstream areas and local sources along the tributary. At level 3, the loads allocated to local sources are allocated to the point and non-point sources from different towns. At level 4, the loads allocated to non-point sources in each town are allocated to different villages. Compared with traditional forms of pollutant load allocation methods, PLHA can combine the advantages of different methods which put different priority weights on equity and efficiency, and the PLHA is easy to understand for stakeholders and more flexible to adjust when applied in practical cases. Copyright © 2015 Elsevier B.V. All rights reserved.

Patterns and processes of nutrient transfers from land to water: a catchment approach to evaluate Good Agricultural Practice in Ireland

NASA Astrophysics Data System (ADS)

Mellander, P.-E.; Melland, A. R.; Shortle, G.; Wall, D.; Mechan, S.; Buckley, C.; Fealy, R.; Jordan, P.

2009-04-01

Eutrophication of fresh, transitional and coastal waters by excessive nutrient inputs is one of the most widespread water quality problems in developed countries. Sources of nutrient nitrogen (N) and phosphorus (P) can come from a multiplicity of sources and be dependent on numerous hydrological controls from catchments with both urban and agricultural landuses. Aquatic impacts are widely reported as a result of excessive nutrient transfers from land to water and include changes in ecological integrity and loss of amenity. In the European Union, the Water Framework Directive (WFD) and associated Directives are the key structures with which member states must develop national and often trans-national polices to deal with issues of water resources management. The linked Nitrates Directive is particularly concerned with integrating sustainable agriculture and good water quality objectives and is written into national polices. In Ireland this policy is the Nitrates Directive National Action Programme (NAP), Statutory Instruction 378, Good Agricultural Practise regulation, and amongst other things, sets targets and limits on the use of organic and inorganic fertilisers, soil fertility and slurry/fertiliser spreading and cultivation times. To evaluate the effectiveness of this policy, Teagasc, the Irish Agriculture and Food Development Authority, is undertaking a catchment scale audit on sources, sinks, and changes in nutrient use and export over several years. The Agricultural Catchments Programme is based on a science-stakeholder-management partnership to generate knowledge and specifically to protect water quality from nitrogen and phosphorus transfers within the constraints of the requirements of modern Irish agricultural practises. Eight catchments of 5-12 km2 have been selected for the programme to represent a range of agricultural intensities and vulnerabilities to nitrogen and phosphorus loss including catchments that are situated on permeable and impermeable grassland soils; areas where arable production represents a significant landuse; and catchments on productive and unproductive aquifers. The catchments were identified using a GIS-based multicriteria decision analysis with objective criteria that included landuse data (including agricultural and settlement statistics) combined with soils and geology data to evaluate the risk of P and N loss. Shortlisted catchments were then finalised using practical criteria based on the potential for hydrometry and hydrochemistry research. In each catchment, a conceptual model approach is being used to hypothesize the sources, seasonal mobilisation and pathways of nutrients and water through the soil/subsoil system and transfer into surface and ground water systems to stratify each catchment experimental design. Knowledge of the nutrient management of each catchment farm and resulting soil fertility will be used to monitor the sources of agricultural N and P. Environmental soil nutrient tests will provide baselines and checks on the potential for mobilisation. Areas of high soil fertility that are coincident with high surface or sub-surface hydrological connectivity will be monitored for subsequent nutrient transfer. Other potential nutrient source loads within the catchments, such as rural waste-water treatment plants and domestic septic systems, will be factored in as non-agricultural sources. Similarly, the potential for farmyard transfers will also be assessed. The net balance of nutrient transfer at the catchment outlets will be monitored using a high resolution method that is coincident with hydrometric measurements to ensure that there is a full understanding of the inter-dependence between point and diffuse nutrient transfers and hydrodynamics. This source to transfer approach is highly appropriate and a move towards inductive understanding of nutrient use and export in river catchments - the scale at which policies for water resources management will be assessed under the WFD. The data are also highly conducive to constraining catchment scale, distributed models for predicting chemical transfers in runoff. As the Programme is aiming to integrate the often perceived contentious objectives of water quality management with those of sustainable agriculture, farm economics will also be monitored at the same time and an assessment made of farmer attitudes. An advisory programme is also a major component and dedicated farm advisors will ensure that farmers are fully appraised of obligations and opportunities in the National Action Programme.

SOURCES AND ESTIMATED LOAD OF BIOAVAILABLE NITROGEN ATTRIBUTABLE TO CHRONIC NITROGEN EXPOSURE AND CHANGED ECOSYSTEM STRUCTURE AND FUNCTION

EPA Science Inventory

Bioavailable nitrogen is a limiting nutrient throughout the Eastern United States. Research demonstrates that exposure to large doses of nitrogen leads to deleterious environmental impacts. However, effects of chronic exposure to lower doses of nitrogen are not well known. Since...

The Utilization of Edge-of-Field Monitoring of Agricultural Runoff in Addressing Nonpoint Source Pollution

USDA-ARS?s Scientific Manuscript database

While basin-scale studies and modeling are important tools in relating land uses to water quality concerns, edge-of-field monitoring (EOFM) provides the necessary resolution to spatially target, design, and evaluate in-field conservation practices for reducing nutrient and sediment loading from agri...

SOURCES AND ESTIMATED LOAD OF BIOAVAILABLE NITROGEN ATTRIBUTED TO CHRONIC NITROGEN EXPOSURE AND CHANGED ECOSYSTEM STRUCTURE AND FUNCTION

EPA Science Inventory

Bioavailable nitrogen is a limiting nutrient throughout the Eastern United States. Research demonstrates that exposure to large doses of nitrogen leads to deleterious environmental impacts. However, effects of chronic exposure to lower doses of nitrogen are under-appreciated. ...

QUANTIFYING SEASONAL SHIFTS IN NITROGEN SOURCES TO OREGON ESTUARIES. PART I: EMPIRICAL 15N MACROALGAE DATA

EPA Science Inventory

“Green Tides” are typically considered to be a symptom of eutrophication associated with anthropogenic nutrient loading. In many estuaries along the Pacific Northwest (PNW), the seasonal development of macroalgal mats or “Green Tides” coincides with the initiation of coastal upw...

Effect of topographic characteristics on compound topographic index for identification of gully channel initiation locations

USDA-ARS?s Scientific Manuscript database

Sediment loads from gully erosion can be a significant sediment source within watershed resulting in major contributions to water quality problems, reduction of crop productivity by removal of nutrient rich top soil, and damaging downstream ecosystems. Areas containing a high probability of forming ...

Effects of legacy sediment removal on hydrology and biogeochemistryin a first order stream in Pennsylvania, USA

EPA Science Inventory

Historic forest conversion to agriculture and associated stream impoundments built for hydropower led to extensive burial of valley bottoms throughout the mid-Atlantic region of the US. These so-called legacy sediments are sources of nutrient and sediment pollutant loads to down...

Managing manure for sustainable livestock production in the Chesapeake Bay Watershed

USDA-ARS?s Scientific Manuscript database

Manure presents one of the greatest challenges to livestock operations in the Chesapeake Bay Watershed. The Chesapeake Bay is threatened by excessive nutrient loadings and, according to the U.S. Environmental Protection Agency, manure is the source of 18% of the nitrogen and 27% of the phosphorus en...

EUTROPHICATION MODELING CAPABILITIES FOR WATER QUALITY AND INTEGRATION TOWARDS ECOLOGICAL ENDPOINTS

EPA Science Inventory

A primary environmental focus for the use of mathematical models is for characterization of sources of nutrients and sediments and their relative loadings from large river basins, and the impact of land uses from smaller sub-basins on water quality in rivers, lakes, and estuaries...

Hydrologic and Water-Quality Characterization and Modeling of the Onondaga Lake Basin, Onondaga County, New York

USGS Publications Warehouse

Coon, William F.; Reddy, James E.

2008-01-01

Onondaga Lake in Onondaga County, New York, has been identified as one of the Nation?s most contaminated lakes as a result of industrial and sanitary-sewer discharges and stormwater nonpoint sources, and has received priority cleanup status under the national Water Resources Development Act of 1990. A basin-scale precipitation-runoff model of the Onondaga Lake basin was identified as a desirable water-resources management tool to better understand the processes responsible for the generation of loads of sediment and nutrients that are transported to Onondaga Lake. During 2003?07, the U.S. Geological Survey (USGS) developed a model based on the computer program, Hydrological Simulation Program?FORTRAN (HSPF), which simulated overland flow to, and streamflow in, the major tributaries of Onondaga Lake, and loads of sediment, phosphorus, and nitrogen transported to the lake. The simulation period extends from October 1997 through September 2003. The Onondaga Lake basin was divided into 107 subbasins and within these subbasins, the land area was apportioned among 19 pervious and impervious land types on the basis of land use and land cover, hydrologic soil group (HSG), and aspect. Precipitation data were available from three sources as input to the model. The model simulated streamflow, water temperature, concentrations of dissolved oxygen, and concentrations and loads of sediment, orthophosphate, total phosphorus, nitrate, ammonia, and organic nitrogen in the four major tributaries to Onondaga Lake?Onondaga Creek, Harbor Brook, Ley Creek, and Ninemile Creek. Simulated flows were calibrated to data from nine USGS streamflow-monitoring sites; simulated nutrient concentrations and loads were calibrated to data collected at six of the nine streamflow-monitoring sites. Water-quality samples were collected, processed, and analyzed by personnel from the Onondaga County Department of Water Environment Protection. Several time series of flow, and sediment and nutrient loads were generated for known sources of these constituents, including the Tully Valley mudboils (flow and sediment), Otisco Lake (flow and nutrients), the Marcellus wastewater-treatment plant (flow and nutrients), and springs from carbonate bedrock (flow). Runoff from the impervious sewered areas of the City of Syracuse was adjusted for the quantity that was treatable at the county wastewater-treatment plant; the excess flows were routed to nearby streams through combined-sanitary-and-storm-sewer overflows. The mitigative effects that the Onondaga Reservoir and Otisco Lake were presumed to have on loads of sediment and particulate constituents were simulated by adjustment of parameter values that controlled sediment settling rates, deposition, and scour in the reservoir and lake. Graphical representations of observed and simulated data, and relevant statistics, were compared to assess model performance. Simulated daily and monthly streamflows were rated ?very good? (within 10 percent of observed flows) at all calibration sites, except Onondaga Creek at Cardiff, which was rated ?fair? (10?15 percent difference). Simulations of monthly average water temperatures were rated ?very good? (within 7 percent of observed temperatures) at all sites. No observed data were available by which to directly assess the model?s simulation of suspended sediment loads. Available measured total suspended solids data provided an indirect means of comparison but, not surprisingly, yielded only ?fair? to ?poor? ratings (greater than 30 percent difference) for simulated monthly sediment loads at half the water-quality calibration sites. Simulations of monthly orthophosphate loads ranged from ?very good? (within 15 percent of measured loads) at three sites to ?poor? (greater than 35 percent difference) at one site; simulations of ammonia nitrogen loads ranged from ?very good? at one site to ?fair? (25?35 percent difference) at two sites. Simulations of monthly total phosphorus, nitrate, and or

Response of non-point source pollutant loads to climate change in the Shitoukoumen reservoir catchment.

PubMed

Zhang, Lei; Lu, Wenxi; An, Yonglei; Li, Di; Gong, Lei

2012-01-01

The impacts of climate change on streamflow and non-point source pollutant loads in the Shitoukoumen reservoir catchment are predicted by combining a general circulation model (HadCM3) with the Soil and Water Assessment Tool (SWAT) hydrological model. A statistical downscaling model was used to generate future local scenarios of meteorological variables such as temperature and precipitation. Then, the downscaled meteorological variables were used as input to the SWAT hydrological model calibrated and validated with observations, and the corresponding changes of future streamflow and non-point source pollutant loads in Shitoukoumen reservoir catchment were simulated and analyzed. Results show that daily temperature increases in three future periods (2010-2039, 2040-2069, and 2070-2099) relative to a baseline of 1961-1990, and the rate of increase is 0.63°C per decade. Annual precipitation also shows an apparent increase of 11 mm per decade. The calibration and validation results showed that the SWAT model was able to simulate well the streamflow and non-point source pollutant loads, with a coefficient of determination of 0.7 and a Nash-Sutcliffe efficiency of about 0.7 for both the calibration and validation periods. The future climate change has a significant impact on streamflow and non-point source pollutant loads. The annual streamflow shows a fluctuating upward trend from 2010 to 2099, with an increase rate of 1.1 m(3) s(-1) per decade, and a significant upward trend in summer, with an increase rate of 1.32 m(3) s(-1) per decade. The increase in summer contributes the most to the increase of annual load compared with other seasons. The annual NH (4) (+) -N load into Shitoukoumen reservoir shows a significant downward trend with a decrease rate of 40.6 t per decade. The annual TP load shows an insignificant increasing trend, and its change rate is 3.77 t per decade. The results of this analysis provide a scientific basis for effective support of decision makers and strategies of adaptation to climate change.

Early warning indicators for river nutrient and sediment loads in tropical seagrass beds: a benchmark from a near-pristine archipelago in Indonesia.

PubMed

van Katwijk, M M; van der Welle, M E W; Lucassen, E C H E T; Vonk, J A; Christianen, M J A; Kiswara, W; al Hakim, I Inayat; Arifin, A; Bouma, T J; Roelofs, J G M; Lamers, L P M

2011-07-01

In remote, tropical areas human influences increase, potentially threatening pristine seagrass systems. We aim (i) to provide a bench-mark for a near-pristine seagrass system in an archipelago in East Kalimantan, by quantifying a large spectrum of abiotic and biotic properties in seagrass meadows and (ii) to identify early warning indicators for river sediment and nutrient loading, by comparing the seagrass meadow properties over a gradient with varying river influence. Abiotic properties of water column, pore water and sediment were less suitable indicators for increased sediment and nutrient loading than seagrass properties. Seagrass meadows strongly responded to higher sediment and nutrient loads and proximity to the coast by decreasing seagrass cover, standing stock, number of seagrass species, changing species composition and shifts in tissue contents. Our study confirms that nutrient loads are more important than water nutrient concentrations. We identify seagrass system variables that are suitable indicators for sediment and nutrient loading, also in rapid survey scenarios with once-only measurements. Copyright © 2011 Elsevier Ltd. All rights reserved.

URBAN/SUBURBAN WATERSHED CHARACTERIZATION

EPA Science Inventory

The ability to characterize the land surface and related pollutant source loadings is critical for reliable watershed modeling. Urban/suburban land uses are the most rapidly growing land use class, generating non-point source pollutant loadings likely to seriously impair streams...

Monitoring and Analysis of Nonpoint Source Pollution - Case study on terraced paddy fields in an agricultural watershed

NASA Astrophysics Data System (ADS)

Chen, Shih-Kai; Jang, Cheng-Shin; Yeh, Chun-Lin

2013-04-01

The intensive use of chemical fertilizer has negatively impacted environments in recent decades, mainly through water pollution by nitrogen (N) and phosphate (P) originating from agricultural activities. As a main crop with the largest cultivation area about 0.25 million ha per year in Taiwan, rice paddies account for a significant share of fertilizer consumption among agriculture crops. This study evaluated the fertilization of paddy fields impacting return flow water quality in an agricultural watershed located at Hsinchu County, northern Taiwan. Water quality monitoring continued for two crop-periods in 2012, around subject to different water bodies, including the irrigation water, drainage water, and shallow groundwater. The results indicated that obviously increasing of ammonium-N, nitrate-N and TP concentrations in the surface drainage water were observed immediately following three times of fertilizer applications (including basal, tillering, and panicle fertilizer application), but reduced to relatively low concentrations after 7-10 days after each fertilizer application. Groundwater quality monitoring showed that the observation wells with the more shallow water depth, the more significant variation of concentrations of ammonium-N, nitrate-N and TP could be observed, which means that the contamination potential of nutrient of groundwater is related not only to the impermeable plow sole layer but also to the length of percolation route in this area. The study also showed that the potential pollution load of nutrient could be further reduced by well drainage water control and rational fertilizer management, such as deep-water irrigation, reuse of return flow, the rational application of fertilizers, and the SRI (The System of Rice Intensification) method. The results of this study can provide as an evaluation basis to formulate effective measures for agricultural non-point source pollution control and the reuse of agricultural return flow. Keywords:Chemical fertilizer, Nitrogen, Phosphorus, Paddy field, Non-point source pollution.

Influence of the South-North Water Diversion Project and the mitigation projects on the water quality of Han River.

PubMed

Zhu, Y P; Zhang, H P; Chen, L; Zhao, J F

2008-11-15

Situated in the central part of China, the Han River Basin is undergoing rapid social and economic development with some human interventions to be made soon which will profoundly influence the water environment of the basin. The integrated MIKE 11 model system comprising of a rainfall-runoff model (NAM), a non-point load evaluation model (LOAD), a hydrodynamic model (MIKE 11 HD) and a water quality model (ECOLab) was applied to investigate the impact of the Middle Route of the South-North Water Diversion Project on the Han River and the effectiveness of the 2 proposed mitigation projects, the 22 wastewater treatment plants (WWTPs) and the Yangtze-Han Water Diversion Project. The study concludes that business as usual will lead to a continuing rapid deterioration of the water quality of the Han River. Implementation of the Middle Route of the South-North Water Diversion Project in 2010 will bring disastrous consequence in the form of the remarkably elevated pollution level and high risk of algae bloom in the middle and lower reaches. The proposed WWTPs will merely lower the pollution level in the reach by around 10%, while the Yangtze-Han Water Diversion Project can significantly improve the water quality in the downstream 200-km reach. The results reveal that serious water quality problem will emerge in the middle reach between Xiangfan and Qianjiang in the future. Implementation of the South-North Water Diversion Project (phase II) in 2030 will further exacerbate the problem. In order to effectively improve the water quality of the Han River, it is suggested that nutrient removal processes should be adopted in the proposed WWTPs, and the pollution load from the non-point sources, especially the load from the upstream Henan Province, should be effectively controlled.

Microbial Source Module (MSM): Documenting the Science and Software for Discovery, Evaluation, and Integration

EPA Science Inventory

The Microbial Source Module (MSM) estimates microbial loading rates to land surfaces from non-point sources, and to streams from point sources for each subwatershed within a watershed. A subwatershed, the smallest modeling unit, represents the common basis for information consume...

Heavy metal transport in large river systems: heavy metal emissions and loads in the Rhine and Elbe river basins

NASA Astrophysics Data System (ADS)

Vink, Rona; Behrendt, Horst

2002-11-01

Pollutant transport and management in the Rhine and Elbe basins is still of international concern, since certain target levels set by the international committees for protection of both rivers have not been reached. The analysis of the chain of emissions of point and diffuse sources to river loads will provide policy makers with a tool for effective management of river basins. The analysis of large river basins such as the Elbe and Rhine requires information on the spatial and temporal characteristics of both emissions and physical information of the entire river basin. In this paper, an analysis has been made of heavy metal emissions from various point and diffuse sources in the Rhine and Elbe drainage areas. Different point and diffuse pathways are considered in the model, such as inputs from industry, wastewater treatment plants, urban areas, erosion, groundwater, atmospheric deposition, tile drainage, and runoff. In most cases the measured heavy metal loads at monitoring stations are lower than the sum of the heavy metal emissions. This behaviour in large river systems can largely be explained by retention processes (e.g. sedimentation) and is dependent on the specific runoff of a catchment. Independent of the method used to estimate emissions, the source apportionment analysis of observed loads was used to determine the share of point and diffuse sources in the heavy metal load at a monitoring station by establishing a discharge dependency. The results from both the emission analysis and the source apportionment analysis of observed loads were compared and gave similar results. Between 51% (for Hg) and 74% (for Pb) of the total transport in the Elbe basin is supplied by inputs from diffuse sources. In the Rhine basin diffuse source inputs dominate the total transport and deliver more than 70% of the total transport. The diffuse hydrological pathways with the highest share are erosion and urban areas.

Apportioning riverine DIN load to export coefficients of land uses in an urbanized watershed.

PubMed

Shih, Yu-Ting; Lee, Tsung-Yu; Huang, Jr-Chuan; Kao, Shuh-Ji; Chang

2016-08-01

The apportionment of riverine dissolved inorganic nitrogen (DIN) load to individual land use on a watershed scale demands the support of accurate DIN load estimation and differentiation of point and non-point sources, but both of them are rarely quantitatively determined in small montane watersheds. We introduced the Danshui River watershed of Taiwan, a mountainous urbanized watershed, to determine the export coefficients via a reverse Monte Carlo approach from riverine DIN load. The results showed that the dynamics of N fluctuation determines the load estimation method and sampling frequency. On a monthly sampling frequency basis, the average load estimation of the methods (GM, FW, and LI) outperformed that of individual method. Export coefficient analysis showed that the forest DIN yield of 521.5kg-Nkm(-2)yr(-1) was ~2.7-fold higher than the global riverine DIN yield (mainly from temperate large rivers with various land use compositions). Such a high yield was attributable to high rainfall and atmospheric N deposition. The export coefficient of agriculture was disproportionately larger than forest suggesting that a small replacement of forest to agriculture could lead to considerable change of DIN load. The analysis of differentiation between point and non-point sources showed that the untreated wastewater (non-point source), accounting for ~93% of the total human-associated wastewater, resulted in a high export coefficient of urban. The inclusion of the treated and untreated wastewater completes the N budget of wastewater. The export coefficient approach serves well to assess the riverine DIN load and to improve the understanding of N cascade. Copyright © 2016 Elsevier B.V. All rights reserved.

Effects of wastewater effluent discharge and treatment facility upgrades on environmental and biological conditions of Indian Creek, Johnson County, Kansas, June 2004 through June 2013

USGS Publications Warehouse

Graham, Jennifer L.; Stone, Mandy L.; Rasmussen, Teresa J.; Foster, Guy M.; Poulton, Barry C.; Paxson, Chelsea R.; Harris, Theodore D.

2014-01-01

Indian Creek is one of the most urban drainage basins in Johnson County, Kansas, and environmental and biological conditions of the creek are affected by contaminants from point and other urban sources. The Johnson County Douglas L. Smith Middle Basin (hereafter referred to as the “Middle Basin”) and Tomahawk Creek Wastewater Treatment Facilities (WWTFs) discharge to Indian Creek. In summer 2010, upgrades were completed to increase capacity and include biological nutrient removal at the Middle Basin facility. There have been no recent infrastructure changes at the Tomahawk Creek facility; however, during 2009, chemically enhanced primary treatment was added to the treatment process for better process settling before disinfection and discharge with the added effect of enhanced phosphorus removal. The U.S. Geological Survey, in cooperation with Johnson County Wastewater, assessed the effects of wastewater effluent on environmental and biological conditions of Indian Creek by comparing two upstream sites to four sites located downstream from the WWTFs using data collected during June 2004 through June 2013. Environmental conditions were evaluated using previously and newly collected discrete and continuous data and were compared with an assessment of biological community composition and ecosystem function along the upstream-downstream gradient. This study improves the understanding of the effects of wastewater effluent on stream-water and streambed sediment quality, biological community composition, and ecosystem function in urban areas. After the addition of biological nutrient removal to the Middle Basin WWTF in 2010, annual mean total nitrogen concentrations in effluent decreased by 46 percent, but still exceeded the National Pollutant Discharge Elimination System (NPDES) wastewater effluent permit concentration goal of 8.0 milligrams per liter (mg/L); however, the NPDES wastewater effluent permit total phosphorus concentration goal of 1.5 mg/L or less was achieved at the Middle Basin WWTF. At the Tomahawk Creek WWTF, after the addition of chemically enhanced primary treatment in 2009, effluent discharges also had total phosphorus concentrations below 1.5 mg/L. After the addition of biological nutrient removal, annual total nitrogen and phosphorus loads from the Middle Basin WWTF decreased by 42 and 54 percent, respectively, even though effluent volume increased by 11 percent. Annual total phosphorus loads from the Tomahawk Creek WWTF after the addition of chemically enhanced primary treatment decreased by 54 percent despite a 33-percent increase in effluent volume. Total nitrogen and phosphorus from the WWTFs contributed between 30 and nearly 100 percent to annual nutrient loads in Indian Creek depending on streamflow conditions. In-stream total nitrogen primarily came from wastewater effluent except during years with the highest streamflows. Most of the in-stream total phosphorus typically came from effluent during dry years and from other urban sources during wet years. During 2010 through 2013, annual mean discharge from the Middle Basin WWTF was about 75 percent of permitted design capacity. Annual nutrient loads likely will increase when the facility is operated at permitted design capacity; however, estimated maximum annual nutrient loads from the Middle Basin WWTF were 27 to 38 percent lower than before capacity upgrades and the addition of biological nutrient removal to treatment processes. Thus, the addition of biological nutrient removal to the Middle Basin wastewater treatment process should reduce overall nutrient loads from the facility even when the facility is operated at permitted design capacity. The effects of wastewater effluent on the water quality of Indian Creek were most evident during below-normal and normal streamflows (about 75 percent of the time) when wastewater effluent represented about 24 percent or more of total streamflow. Wastewater effluent had the most substantial effect on nutrient concentrations in Indian Creek. Total and inorganic nutrient concentrations at the downstream sites during below-normal and normal streamflows were 10 to 100 times higher than at the upstream sites, even after changes in treatment practices at the WWTFs. Median total phosphorus concentrations during below-normal and normal streamflows at a downstream site were 43 percent lower following improvements in wastewater treatment processes. Similar decreases in total nitrogen were not observed, likely because total nitrogen concentrations only decreased in Middle Basin effluent and wastewater contributed a higher percentage to streamflows when nutrient samples were collected during the after-upgrade period. The wastewater effluent discharges to Indian Creek caused changes in stream-water quality that may affect biological community structure and ecosystem processes, including higher concentrations of bioavailable nutrients (nitrate and orthophosphorus) and warmer water temperatures during winter months. Other urban sources of contaminants also caused changes in stream-water quality that may affect biological community structure and ecosystem processes, including higher turbidities downstream from construction areas and higher specific conductance and chloride concentrations during winter months. Chloride concentrations exceeded acute and chronic exposure criteria at all Indian Creek study sites, regardless of wastewater influence, for weeks or months during winter. Streambed sediment chemistry was affected by wastewater (elevated nutrient and organic wastewater-indicator compound concentrations) and other contaminants from urban sources (elevated polyaromatic hydrocarbon concentrations). Overall habitat conditions were suboptimal or marginal at all sites; general decline in habitat conditions along the upstream-downstream gradient likely was caused by the cumulative effects of urbanization with increasing drainage basin size. Wastewater effluent likely affected algal periphyton biomass and community composition, primary production, and community respiration in Indian Creek. Functional stream health, evaluated using a preliminary framework based on primary production and community respiration, was mildly or severely impaired at most downstream sites relative to an urban upstream Indian Creek site. The mechanistic cause of the changes in these biological variables are unclear, though elevated nutrient concentrations were positively correlated with algal biomass, primary production, and community respiration. Macroinvertebrate communities indicated impairment at all sites, and Kansas Department of Health and Environment aquatic life support scores indicated conditions nonsupporting of aquatic life, regardless of wastewater influences. Urban influences, other than wastewater effluent discharge, likely control macroinvertebrate community structure in Indian Creek. Changes in treatment processes at the Middle Basin and Tomahawk Creek WWTFs improved wastewater effluent quality and decreased nutrient loads, but wastewater effluent discharges still had negative effects on the environmental and biological conditions at downstream Indian Creek sites. Wastewater effluent discharge into Indian Creek likely contributed to changes in measures of ecosystem structure (streamflow, water and streambed-sediment chemistry, algal biomass, and algal periphyton community composition) and function (primary production and community respiration) along the upstream-downstream gradient. Wastewater effluent discharges maintained streamflows and increased nutrient concentrations, algal biomass, primary production, and community respiration at the downstream sites. Functional stream health was severely impaired downstream from the Middle Basin WWTF and mildly impaired downstream from the Tomahawk WWTF relative to the urban upstream site. As distance from the Middle Basin WWTF increased, nutrient concentrations, algal biomass, primary production, and community respiration decreased, and functional stream health was no longer impaired 9.5 kilometers downstream from the discharge relative to the urban upstream site. Therefore, although wastewater effluent caused persistent changes in environmental and biological conditions and functional stream health at sites located immediately downstream from WWTF effluent discharges, some recovery to conditions more similar to the urban upstream site occurred within a relatively short distance.

Geochemical processes in the Onyx River, Wright Valley, Antarctica: Major ions, nutrients, trace metals

NASA Astrophysics Data System (ADS)

Green, William J.; Stage, Brian R.; Preston, Adam; Wagers, Shannon; Shacat, Joseph; Newell, Silvia

2005-02-01

We present data on major ions, nutrients and trace metals in an Antarctic stream. The Onyx River is located in Wright Valley (77-32 S; 161-34 E), one of a group of ancient river and glacier-carved landforms that comprise the McMurdo Dry Valleys of Antarctica. The river is more than 30 km long and is the largest of the glacial meltwater streams that characterize this relatively ice-free region near the Ross Sea. The complete absence of rainfall in the region and the usually small contributions of glacially derived tributaries to the main channel make this a comparatively simple system for geochemical investigation. Moreover, the lack of human impacts, past or present, provides an increasingly rare window onto a pristine aquatic system. For all major ions and silica, we observe increasing concentrations with distance from Lake Brownworth down to the recording weir near Lake Vanda. Chemical weathering rates are unexpectedly high and may be related to the rapid dissolution of ancient carbonate deposits and to the severe physical weathering associated with the harsh Antarctic winter. Of the nutrients, nitrate and dissolved reactive phosphate appear to have quite different sources. Nitrate is enriched in waters near the Lower Wright Glacier and may ultimately be derived from stratospheric sources; while phosphate is likely to be the product of chemical weathering of valley rocks and soils. We confirm the work of earlier investigations regarding the importance of the Boulder Pavement as a nutrient sink. Dissolved Mn, Fe, Ni, Cu, and Cd are present at nanomolar levels and, in all cases, the concentrations of these metals are lower than in average world river water. We hypothesize that metal uptake and exchange with particulate phases along the course of the river may serve as a buffer for the dissolved load. Concurrent study of these three solute classes points out significant differences in the mechanisms and sites of their removal from the Onyx River.

Rhodhiss Lake, North Carolina; analysis of ambient conditions and simulation of hydrodynamics, constituent transport, and water-quality characteristics, 1993-94

USGS Publications Warehouse

Giorgino, M.J.; Bales, J.D.

1997-01-01

From January 1993 through March 1994, the U.S. Geological Survey conducted an investigation of Rhodhiss Lake in cooperation with the Western Piedmont Council of Governments. Objectives of the investigation were to describe ambient hydrologic and water-quality conditions, to estimate loadings of nutrients and suspended solids from selected tributaries and point sources, and to simulate hydraulic circulation and water-quality characteristics in Rhodhiss Lake using a hydrodynamic computer model. The riverine headwaters of Rhodhiss Lake were unstratified, well oxygenated, and contained relatively high concentrations of suspended solids and nutrients throughout the study period. In general, concentrations of suspended solids, nitrate, orthophosphate, and total phosphorus decreased in a downstream direction from the headwaters to the Rhodhiss Dam. However, increases in specific conductance frequently were observed downstream from a wastewater discharge near mid-reservoir. From mid-reservoir to the dam, Rhodhiss Lake thermally stratified during the summer of 1993. In this reach, dissolved oxygen was rapidly depleted from the bottom waters beginning in May 1993, and anoxic conditions persisted in the hypolimnion through the summer. During summer stratification, concentrations of nitrite plus nitrate, ammonia, and orthophosphate were low in the epilimnion, but concentrations of ammonia, orthophosphate, and total phosphorus increased in the hypolimnion. During fall and winter, Rhodhiss Lake was characterized by alternating periods of stratification and mixing. A maximum chlorophyll-a concentration of 52 micrograms per liter was observed at mid-reservoir on November 17, 1993, and was the only value that exceeded the North Carolina water-quality standard of 40 micrograms per liter. Concentrations of fecal coliform bacteria exceeded 200 colonies per 100 milliliters in the headwaters of Rhodhiss Lake 37 percent of the time, and at mid-reservoir and in the forebay 16 percent of the time. In Lower Creek, a tributary to Rhodhiss Lake, concentrations of fecal coliform bacteria exceeded 200 colonies per 100 milliliters in 76 percent of the samples. This stream also contained elevated concentrations of nitrite plus nitrate, phosphorus, and specific conductance. Loading estimates showed that almost all of the suspended solids and the majority of the nitrogen and phosphorus entering the headwaters of Rhodhiss Lake originated from nonpoint sources. During the investigation, point sources accounted for less than 1 percent of the suspended solids load to the reservoir headwaters, but point sources accounted for up to 27 and 22 percent of the total nitrogen and total phosphorus loads, respectively. Additional loadings of nitrogen and phosphorus entered Rhodhiss Lake by municipal wastewater discharge near mid-reservoir. The U.S. Army Corps of Engineers CE-QUAL-W2 model is a two-dimensional, laterally averaged model that simulates hydrodynamics and water quality. The model was applied to Rhodhiss Lake from Huffman Bridge to Rhodhiss Dam--a distance of 18.5 kilometers--and was calibrated using data collected from April 1993 through March 1994. During the simulation period, measured water levels varied a total of 1.32 meters, and water temperatures ranged from 4 to 30 degrees Celsius. The calibrated model provided good agreement between measured and simu- lated water levels at Rhodhiss Dam. Likewise, simulated water temperatures were generally within 2 degrees Celsius of measured values; however, the model tended to overpredict temperatures near the bottom of the reservoir by 1 to 3 degrees Celsius during warm months. This suggests that the model, as calibrated, overpredicts vertical mixing. Simulated dissolved oxygen concentrations followed the same general patterns and magnitudes as measured values, and there was good agreement between simulated and measured frequency of occurrence of dissolved oxygen concentrations less than 5 milligra

Nitrogen deposition and exceedance of critical loads for nutrient nitrogen in Irish grasslands.

PubMed

Henry, Jason; Aherne, Julian

2014-02-01

High resolution nitrogen (N) deposition maps were developed to assess the exceedance of empirical critical loads of nutrient N for grasslands in Ireland. Nitrogen emissions have remained relatively constant during the past 20 yrs and are projected to remain constant under current legislation. Total N deposition (estimated as wet nitrate [NO3(-)] and ammonium [NH4(+)] plus dry NO× and NH3) ranged from 2 to 22 kg Nha(-1)yr(-1) (mean=12 kg Nha(-1)yr(-1)) to grasslands. Empirical critical loads for nutrient N were set at 15 kg Nha(-1)yr(-1) for both acid and calcareous grasslands; exceedance was observed for ~35% (~2,311 km(2)) of mapped acid grasslands. In contrast, only ~9% of calcareous grasslands (~35 km(2)) received N deposition in excess of the critical load. Reduced N deposition (primarily dry NH3) represented the dominant form to grasslands (range 55-90%) owing to significant emissions associated with livestock (primarily cattle). The extent of exceedance in acid grasslands suggests that N deposition to this habitat type may lead to adverse impacts such as a decline in plant species diversity and soil acidification. Further, given that elevated N deposition was dominated by NH3 associated with agricultural emissions rather than long-range transboundary sources, future improvements in air quality need to be driven by national policies. © 2013.

Effects of Nitrogen Inputs and Watershed Characteristics on ...

EPA Pesticide Factsheets

Nitrogen (N) inputs to the landscape have been linked previously to N loads exported from watersheds at the national scale; however, stream N concentration is arguably more relevant than N load for drinking water quality, freshwater biological responses and establishment of nutrient criteria. In this study, we combine national-scale anthropogenic N input data, including synthetic fertilizer, crop biological N fixation, manure applied to farmland, atmospheric N deposition, and point source inputs, with data from the 2008-09 National Rivers and Streams Assessment to quantify the relationship between N inputs and in-stream concentrations of total N (TN), dissolved inorganic N (DIN), and total organic N (TON) (calculated as TN – DIN). In conjunction with simple linear regression, we use multiple regression to understand how watershed and stream reach attributes modify the effect of N inputs on N concentrations. Median TN was 0.50 mg N L-1 with a maximum of 25.8 mg N L-1. Total N inputs to the watershed ranged from less than 1 to 196 kg N ha-1 y-1, with a median of 14.4 kg N ha-1 y-1. Atmospheric N deposition was the single largest anthropogenic N source in the majority of sites, but, agricultural sources generally dominate total N inputs in sites with elevated N concentrations. The sum of all N inputs were positively correlated with concentrations of all forms of N [r2 = 0.44, 0.43, and 0.18 for TN, DIN, and TON, respectively (all log-transformed), n = 1112], indi

BACTERIA SOURCE TRACKING AND HOST SPECIES SPECIFICITY ANALYSIS

EPA Science Inventory

Point and non-point pollution sources of fecal pollution on a watershed adversely impact the quality of drinking source waters and recreational waters. States are required to develop total maximum daily loads (TMDLs) and devise best management practices (BMPs) to reduce the pollu...

Using a Hydrodynamic and Biogeochemical Model to Investigate the Effects of Nutrient Loading from a Wastewater Treatment Plant into Lake Michigan

NASA Astrophysics Data System (ADS)

Khazaei, B.; Bravo, H.; Bootsma, H.

2017-12-01

There is clear evidence that excessive nutrient, in particular phosphorus (P), loading into Lake Michigan has produced significant problems, such as algal blooms, hypoxia, and reduced water quality. Addressing those problems requires understanding the transport and fate of P in the lake. The dominance of mixing and dispersion processes on the P transport has been demonstrated, yet recent research has shown the remarkable influence of dreissenid mussels and Cladophora on water clarity and the P budget. Since mussels and Cladophora tend to concentrate near the coastlines, nearshore-offshore P exchange is of a big importance. In this research, a computer model was developed to simulate the P cycle by incorporating the biogeochemical processes relevant to the transport of P into a 3D high-resolution hydrodynamic model. The near-bottom biogeochemical model consists of three linked modules: Cladophora, mussel, and sediment storage modules. The model was applied to the Milwaukee Metropolitan Sewerage District South Shore Wastewater Treatment Plant, between June and October of 2013 and 2015, as a case study. The plant outfall introduces a point source of P into the study domain—the nearshore zone of Lake Michigan adjacent to Milwaukee County. The model was validated against field observations of water temperature, dissolved phosphorus (DP), particulate phosphorus (PP), Cladophora biomass, and P content. The model simulations showed reasonably good agreement with field measurements. Model results showed a) different temporal patterns in 2013 and 2015, b) a larger range of fluctuations in DP than that in PP, and c) that the effects of mussels and Cladophora could explain the differences in patterns and ranges. PP concentrations showed more frequent spikes of concentration in 2013 due to resuspension events during that year because of stronger winds. The model is being applied as a management tool to test scenarios of nutrient loading to determine effluent P limits for the treatment plant. The alongshore lengths of the surface layer-footprints of total phosphorus (TP) that exceeded the target concentration of 7 μg L-1 during 25% of the summer season were approximately 30 and 24 Km in 2013 and 2015, respectively. That result indicates that the footprint was reduced by the application of a more efficient loading scenario in 2015.

Watershed scale assessment of the impact of forested riparian zones on stream water quality

Treesearch

J. A. Webber; K. W. J. Williard; M. R. Whiles; M. L. Stone; J. J. Zaczek; D. K. Davie

2003-01-01

Federal and state land management agencies have been promoting forest and grass riparian zones to combat non-point source nutrient and sediment pollution of our nations' waters. The majority of research examining the effectiveness of riparian buffers at reducing nutrient and sediment inputs to streams has been conducted at the field scale. This study took a...

Land Cover - Nutrient Export Relationships in Space and Time

EPA Science Inventory

The relationship between watershed land-cover composition and nutrient export has been well established through several meta-analyses. The meta-analyses reveal that nutrient loads from watersheds dominated by natural vegetation tend to be lower than nutrient loads from watershed...

Estimation of Nitrogen Loads to Two Impaired Reservoirs in the Piedmont Region of North Carolina Using LOADEST and SPARROW Models, 1997-2008

NASA Astrophysics Data System (ADS)

Pointer, B.; Harned, D. A.; Harden, S.

2010-12-01

The loading of nutrients into lacustrine ecosystems is an issue that concerns scientists and policy makers due to the potentially negative effect on drinking water sources. In this study, nitrogen loads are estimated for streams entering two central North Carolina lakes: Falls Lake in Durham County and B. Everett Jordan Lake in Chatham County. Both of these lakes have been placed on the North Carolina list of impaired waters due to excessive concentrations of chlorophyll a. Nutrient management rules are being established for both lakes. This study is being conducted collaboratively as part of the USGS National Water Quality Assessment (NAWQA) and the North Carolina Department of Environment and Natural Resources (NCDENR) nonpoint source 319 program. Water-quality and streamflow data collected from a total of 9 stream sites (4 upstream of Falls Lake; 5 upstream of Jordan Lake) over 11 years (1997-2008) were used to estimate annual nitrogen loads to each lake using the USGS LOADEST (LOAD ESTimation) model (http://water.usgs.gov/software/loadest/). LOADEST is a multiple linear regression model that estimates constituent loads on a site-specific basis. In order to compare local and regional-scale models, nitrogen loads computed with a SPARROW (SPAtially-Referenced Regression On Watershed attributes) model (http://water.usgs.gov/nawqa/sparrow/) for the southeastern United States also were compiled for each lake. SPARROW model predictions for nitrogen loading are based on a single model year of 2002. The SPARROW model relates empirical nutrient data with watershed characteristics, allowing prediction of loads from all drainage basins that flow into each lake. In contrast, the site-specific data needed for LOADEST is limited to a subset of sampled tributaries. Therefore, for comparison’s sake, load estimations reported in this study from the SPARROW model are summed loads from the subset of basins with corresponding LOADEST calculations - 4 of 56 basins for Falls Lake and 5 of 62 for Jordan Lake, corresponding to 408 mi2 of 772 mi2 for Falls Lake and 1423 mi2 of 1707 mi2 for Jordan Lake. Estimated LOADEST annual loads of nitrogen (N) from 4 tributaries of Falls Lake ranged from 83 tons/yr to 661 tons/yr during 1997-2008, with a median value of 170 tons/yr. Estimated loads summed from the same 4 Falls Lake tributaries using the SPARROW model were 209 tons N/year. The SPARROW model year, 2002, LOADEST results were 119 tons N/yr. LOADEST-estimated nitrogen loads from the 5 tributaries to Jordan Lake ranged from 759 tons/yr to 1,195 tons/yr during 1997-2008, with a median value of 1,093 tons/yr. SPARROW predictions of loads from the same 5 tributaries to Jordan Lake were 2,708 tons N/yr, and 2002 LOADEST results were 1,071 tons N/yr. When SPARROW loads are tabulated using basins from the entire lake watershed, loads to Falls and Jordan Lakes are 755 tons N/yr and 2,816 tons N/yr, respectively. The LOADEST models are useful for tracking localized loading to streams and reservoirs, but are limited to sites with in-stream monitoring data. The SPARROW model is regional in scope, but also can be applied to localized areas to help assess source loading to reservoir tributaries.

Evaluation of the AnnAGNPS Model for Predicting Runoff and Nutrient Export in a Typical Small Watershed in the Hilly Region of Taihu Lake.

PubMed

Luo, Chuan; Li, Zhaofu; Li, Hengpeng; Chen, Xiaomin

2015-09-02

The application of hydrological and water quality models is an efficient approach to better understand the processes of environmental deterioration. This study evaluated the ability of the Annualized Agricultural Non-Point Source (AnnAGNPS) model to predict runoff, total nitrogen (TN) and total phosphorus (TP) loading in a typical small watershed of a hilly region near Taihu Lake, China. Runoff was calibrated and validated at both an annual and monthly scale, and parameter sensitivity analysis was performed for TN and TP before the two water quality components were calibrated. The results showed that the model satisfactorily simulated runoff at annual and monthly scales, both during calibration and validation processes. Additionally, results of parameter sensitivity analysis showed that the parameters Fertilizer rate, Fertilizer organic, Canopy cover and Fertilizer inorganic were more sensitive to TN output. In terms of TP, the parameters Residue mass ratio, Fertilizer rate, Fertilizer inorganic and Canopy cover were the most sensitive. Based on these sensitive parameters, calibration was performed. TN loading produced satisfactory results for both the calibration and validation processes, whereas the performance of TP loading was slightly poor. The simulation results showed that AnnAGNPS has the potential to be used as a valuable tool for the planning and management of watersheds.

THE COMPARISON OF TWO WATERSHEDS USING A WATERSHED NUTRIENT LOADING MODEL

EPA Science Inventory

Monitoring data, collected from the Yaquina River, Oregon, from 1999 through 2002 were used as the basis for developing the nutrient flux model as part of a larger agency program for quantifying nutrient processes. The PNWL nitrate loading model indicates that the nitrate load is...

EVALUATION OF SAMPLING FREQUENCIES REQUIRED TO ESTIMATE NUTRIENT AND SUSPENDED SEDIMENT LOADS IN LARGE RIVERS

EPA Science Inventory

Nutrients and suspended sediments in streams and large rivers are two major issues facing state and federal agencies. Accurate estimates of nutrient and sediment loads are needed to assess a variety of important water-quality issues including total maximum daily loads, aquatic ec...

Storm event-scale nutrient attenuation in constructed wetlands experiencing a Mediterranean climate: A comparison of a surface flow and hybrid surface-subsurface flow system.

PubMed

Adyel, Tanveer M; Oldham, Carolyn E; Hipsey, Matthew R

2017-11-15

Among different Water Sensitive Urban Design options, constructed wetlands (CWs) are used to protect and restore downstream water quality by attenuating nutrients generated by stormwater runoff. This research compared the nutrient attenuation ability during a diverse population of storm events of two CWs: (a) a hybrid CW with multiple alternating surface flow (SF) and laterite-based subsurface flow (SSF) compartments, and (b) a single stage SF CW. Within-storm variability, nutrient concentrations were assessed at 2 to 3-h intervals at both the main inlet and outlet of each CW. Dissolved oxygen concentrations of the surface waters were also monitored at 10-min intervals using high frequency in situ sensors. Nutrient loads into the CWs were observed to be higher when a high rainfall event occurred, particularly after longer antecedent dry conditions. Longer hydraulic retention times promoted higher attenuation at both sites. However, the relative extent of nutrient attenuation differed between the CW types; the mean total nitrogen (TN) attenuation in the hybrid and SF CW was 45 and 48%, respectively. The hybrid CW attenuated 67% total phosphorus (TP) loads on average, while the SF CW acted as a net TP source. Periodic storm events transitioned the lentic CW into a lotic CW and caused riparian zone saturation; it was therefore hypothesized that such saturation of organic matter rich-riparian zones led to release of TP in the system. The hybrid CW attenuated the released TP in the downstream laterite-based SSF compartments. Diel oxygen metabolism calculated before and after the storm events was found to be strongly correlated with water temperature, solar exposure and antecedent dry condition during the pre-storm conditions. Furthermore, the SF CW showed a significant relationship between overall nutrient load attenuation and the change in oxygen metabolism during the storm perturbation, suggesting oxygen variation could be a useful proxy indicator of CW function. Copyright © 2017 Elsevier B.V. All rights reserved.

Variable primary producer responses to nutrient and ...

EPA Pesticide Factsheets

Mesocosm experiments have been used to evaluate the impacts of nutrient loading on estuarine plant communities in order to develop nutrient response relationships. Mesocosm eutrophication studies tend to focus on long residence time systems. In the Pacific Northwest, many estuaries have high nutrient loads, short water residence times, seasonal macroalgal blooms, while intertidal seagrass meadows persist under what appear to be largely naturally-derived eutrophic conditions. Using experimental mesocosms, we examined how primary producer communities in rapidly flushed systems respond to a range of temperature (10 and 20 °C) and nutrient loads (ambient, 1.5, 3 and 6 x ambient). Thermal and nutrient loading regimes were maintained for three sets of 3 week-duration experiments during the summer of 2013. Statistical analysis was performed using an information criterion approach to evaluate the best fit model. Green macroalgal (GMA) growth and tissue N increased in response to nutrient loading. Irrespective of nutrient load, GMA at 10 °C remained intercalated among seagrass shoots, but at 20 °C formed floating mats that overtopped seagrass. Outgassing of O2 in combination with photosynthetic O2 production likely induced floating mat formation. No phytoplankton blooms were observed. Zostera japonica leaf biomass and C:N responded to temperature while other metrics exhibited no statistically significant difference. Z. marina growth, wasting disease, and morphological

Evidence of chronic anthropogenic nutrient within coastal lagoon reefs adjacent to urban and tourism centers, Kenya: A stable isotope approach.

PubMed

Mwaura, Jelvas; Umezawa, Yu; Nakamura, Takashi; Kamau, Joseph

2017-06-30

The source of anthropogenic nutrient and its spatial extent in three fringing reefs with differing human population gradients in Kenya were investigated using stable isotope approaches. Nutrient concentrations and nitrate-δ 15 N in seepage water indicated that population density and tourism contributed greatly to the extent of nutrient loading to adjacent reefs. Although water-column nutrient analyses did not show any significant difference among the reefs, higher δ 15 N and N contents in macrophytes showed terrestrial nutrients affected primary producers in onshore areas in Nyali and Bamburi reefs, but were mitigated by offshore water intrusion especially at Nyali. On the offshore reef flat, where the same species of macroalgae were not available, complementary use of δ 15 N in sedimentary organic matter suggested inputs of nutrients originated from the urban city of Mombasa. If population increases in the future, nutrient conditions in the shallower reef, Vipingo, may be dramatically degraded due to lower water exchange ratio. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial Source Module (MSM): Documenting the Science ...

EPA Pesticide Factsheets

The Microbial Source Module (MSM) estimates microbial loading rates to land surfaces from non-point sources, and to streams from point sources for each subwatershed within a watershed. A subwatershed, the smallest modeling unit, represents the common basis for information consumed and produced by the MSM which is based on the HSPF (Bicknell et al., 1997) Bacterial Indicator Tool (EPA, 2013b, 2013c). Non-point sources include numbers, locations, and shedding rates of domestic agricultural animals (dairy and beef cows, swine, poultry, etc.) and wildlife (deer, duck, raccoon, etc.). Monthly maximum microbial storage and accumulation rates on the land surface, adjusted for die-off, are computed over an entire season for four land-use types (cropland, pasture, forest, and urbanized/mixed-use) for each subwatershed. Monthly point source microbial loadings to instream locations (i.e., stream segments that drain individual sub-watersheds) are combined and determined for septic systems, direct instream shedding by cattle, and POTWs/WWTPs (Publicly Owned Treatment Works/Wastewater Treatment Plants). The MSM functions within a larger modeling system that characterizes human-health risk resulting from ingestion of water contaminated with pathogens. The loading estimates produced by the MSM are input to the HSPF model that simulates flow and microbial fate/transport within a watershed. Microbial counts within recreational waters are then input to the MRA-IT model (Soller et

Ecological risk assessment of cheese whey effluents along a medium-sized river in southwest Greece.

PubMed

Karadima, Constantina; Theodoropoulos, Chris; Rouvalis, Angela; Iliopoulou-Georgudaki, Joan

2010-01-01

An ecological risk assessment of cheese whey effluents was applied in three critical sampling sites located in Vouraikos river (southwest Greece), while ecological classification using Water Framework Directive 2000/60/EU criteria allowed a direct comparison of toxicological and ecological data. Two invertebrates (Daphnia magna and Thamnocephalus platyurus) and the zebra fish Danio rerio were used for toxicological analyses, while the aquatic risk was calculated on the basis of the risk quotient (RQ = PEC/PNEC). Chemical classification of sites was carried out using the Nutrient Classification System, while benthic invertebrates were collected and analyzed for biological classification. Toxicological results revealed the heavy pollution load of the two sites, nearest to the point pollution source, as the PEC/PNEC ratio exceeded 1.0, while unexpectedly, no risk was detected for the most downstream site, due to the consequent interference of the riparian flora. These toxicological results were in agreement with the ecological analysis: the ecological quality of the two heavily impacted sites ranged from moderate to bad, whereas it was found good for the most downstream site. The results of the study indicate major ecological risk for almost 15 km downstream of the point pollution source and the potentiality of the water quality remediation by the riparian vegetation, proving the significance of its maintenance.

Characteristics of produced water discharged to the Gulf of Mexico hypoxiczone.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veil, J. A.; Kimmell, T. A.; Rechner, A. C.

2005-08-24

Each summer, an area of low dissolved oxygen (the hypoxic zone) forms in the shallow nearshore Gulf of Mexico waters from the Mississippi River Delta westward to near the Texas/Louisiana border. Most scientists believe that the leading contributor to the hypoxic zone is input of nutrients (primarily nitrogen and phosphorus compounds) from the Mississippi and Atchafalaya Rivers. The nutrients stimulate growth of phytoplankton. As the phytoplankton subsequently die, they fall to the bottom waters where they are decomposed by microorganisms. The decomposition process consumes oxygen in the bottom waters to create hypoxic conditions. Sources other than the two rivers mentionedmore » above may also contribute significant quantities of oxygen-demanding pollutants. One very visible potential source is the hundreds of offshore oil and gas platforms located within or near the hypoxic zone. Many of these platforms discharge varying volumes of produced water. However, only limited data characterizing oxygen demand and nutrient concentration and loading from offshore produced water discharges have been collected. No comprehensive and coordinated oxygen demand data exist for produced water discharges in the Gulf of Mexico. This report describes the results of a program to sample 50 offshore oil and gas platforms located within the Gulf of Mexico hypoxic zone. The program was conducted in response to a requirement in the U.S. Environmental Protection Agency (EPA) general National Pollutant Discharge Elimination System (NPDES) permit for offshore oil and gas discharges. EPA requested information on the amount of oxygen-demanding substances contained in the produced water discharges. This information is needed as inputs to several water quality models that EPA intends to run to estimate the relative contributions of the produced water discharges to the occurrence of the hypoxic zone. Sixteen platforms were sampled 3 times each at approximately one-month intervals to give an estimate of temporal variability. An additional 34 platforms were sampled one time. The 50 sampled platforms were scattered throughout the hypoxic zone to give an estimate of spatial variability. Each platform was sampled for biochemical oxygen demand (BOD), total organic carbon (TOC), nitrogen (ammonia, nitrate, nitrite, and total Kjeldahl nitrogen [TKN]), and phosphorus (total phosphorus and orthophosphate). In addition to these parameters, each sample was monitored for pH, conductivity, salinity, and temperature. The sampling provided average platform concentrations for each parameter. Table ES-1 shows the mean, median, maximum, and minimum for the sampled parameters. For some of the parameters, the mean is considerably larger than the median, suggesting that one or a few data points are much higher than the rest of the points (outliers). Chapter 4 contains an extensive discussion of outliers and shows how the sample results change if outliers are deleted from consideration. A primary goal of this study is to estimate the mass loading (lb/day) of each of the oxygen-demanding pollutants from the 50 platforms sampled in the study. Loading is calculated by multiplying concentrations by the discharge volume and then by a conversion factor to allow units to match. The loadings calculated in this study of 50 platforms represent a produced water discharge volume of about 176,000 bbl/day. The total amount of produced water generated in the hypoxic zone during the year 2003 was estimated as 508,000 bbl/day. This volume is based on reports by operators to the Minerals Management Service each year. It reflects the volume of produced water that is generated from each lease, not the volume that is discharged from each platform. The mass loadings from offshore oil and gas discharges to the entire hypoxic zone were estimated by multiplying the 50-platform loadings by the ratio of total water generated to 50-platform discharge volume. The loadings estimated for the 50 platforms and for the entire hypoxic zone are shown in Table ES-2. These estimates and the sampling data from 50 platforms represent the most complete and comprehensive effort ever undertaken to characterize the amount and potential sources of the oxygen demand in offshore oil and gas produced water discharges.« less

DNA BASED MOLECULAR METHODS FOR BACTERIAL SOURCE TRACKING IN WATERSHEDS

EPA Science Inventory

Point and non-point pollution sources of fecal pollution on a watershed adversely impact the quality of drinking source waters and recreational waters. States are required to develop total maximum daily loads (TMDLs) and devise best management practices (BMPs) to reduce the po...

Estimates of Nutrient Loading by Ground-Water Discharge into the Lynch Cove Area of Hood Canal, Washington

USGS Publications Warehouse

Simonds, F. William; Swarzenski, Peter W.; Rosenberry, Donald O.; Reich, Christopher D.; Paulson, Anthony J.

2008-01-01

Low dissolved oxygen concentrations in the waters of Hood Canal threaten marine life in late summer and early autumn. Oxygen depletion in the deep layers and landward reaches of the canal is caused by decomposition of excess phytoplankton biomass, which feeds on nutrients (primarily nitrogen compounds) that enter the canal from various sources, along with stratification of the water column that prevents mixing and replenishment of oxygen. Although seawater entering the canal is the largest source of nitrogen, ground-water discharge to the canal also contributes significant quantities, particularly during summer months when phytoplankton growth is most sensitive to nutrient availability. Quantifying ground-water derived nutrient loads entering an ecologically sensitive system such as Hood Canal is a critical component of constraining the total nutrient budget and ultimately implementing effective management strategies to reduce impacts of eutrophication. The amount of nutrients entering Hood Canal from ground water was estimated using traditional and indirect measurements of ground-water discharge, and analysis of nutrient concentrations. Ground-water discharge to Hood Canal is variable in space and time because of local geology, variable hydraulic gradients in the ground-water system adjacent to the shoreline, and a large tidal range of 3 to 5 meters. Intensive studies of ground-water seepage and hydraulic-head gradients in the shallow, nearshore areas were used to quantify the freshwater component of submarine ground-water discharge (SGD), whereas indirect methods using radon and radium geochemical tracers helped quantify total SGD and recirculated seawater. In areas with confirmed ground-water discharge, shore-perpendicular electrical resistivity profiles, continuous electromagnetic seepage-meter measurements, and continuous radon measurements were used to visualize temporal variations in ground-water discharge over several tidal cycles. The results of these field investigations show that ground-water discharge into the Lynch Cove area of Hood Canal is highly dynamic and strongly affected by the large tidal range. In areas with a steep shoreline and steep hydraulic gradient, ground-water discharge is spatially concentrated in or near the intertidal zone, with increased discharge during low tide. Topographically flat areas with weak hydraulic gradients had more spatial variability, including larger areas of seawater recirculation and more widely dispersed discharge. Measured total-dissolved-nitrogen concentrations in ground water ranged from below detection limits to 2.29 milligrams per liter and the total load entering Lynch Cove was estimated to be approximately 98 ? 10.3 metric tons per year (MT/yr). This estimate is based on net freshwater seepage rates from Lee-type seepage meter measurements and can be compared to estimates derived from geochemical tracer mass balance estimates (radon and radium) of 231 to 749 MT/yr, and previous water-mass-balance estimates (14 to 47 MT/ yr). Uncertainty in these loading estimates is introduced by complex biogeochemical cycles of relevant nutrient species, the representativeness of measurement sites, and by energetic dynamics at the coastal aquifer-seawater interface caused by tidal forcing.

Accounting for heterogeneity of nutrient dynamics in riverscapes through spatially distributed models

NASA Astrophysics Data System (ADS)

Wollheim, W. M.; Stewart, R. J.

2011-12-01

Numerous types of heterogeneity exist within river systems, leading to hotspots of nutrient sources, sinks, and impacts embedded within an underlying gradient defined by river size. This heterogeneity influences the downstream propagation of anthropogenic impacts across flow conditions. We applied a river network model to explore how nitrogen saturation at river network scales is influenced by the abundance and distribution of potential nutrient processing hotspots (lakes, beaver ponds, tributary junctions, hyporheic zones) under different flow conditions. We determined that under low flow conditions, whole network nutrient removal is relatively insensitive to the number of hotspots because the underlying river network structure has sufficient nutrient processing capacity. However, hotspots become more important at higher flows and greatly influence the spatial distribution of removal within the network at all flows, suggesting that identification of heterogeneity is critical to develop predictive understanding of nutrient removal processes under changing loading and climate conditions. New temporally intensive data from in situ sensors can potentially help to better understand and constrain these dynamics.

Suspended sediment impact on chlorophyll a, nitrogen and phosphorus relationships in Moon Lake, MS

USDA-ARS?s Scientific Manuscript database

Moon Lake, MS is a 947 ha. oxbow lake of the Mississippi River Alluvial Plain also known as the Mississippi Delta. Water was sampled from five sites, bi-weekly from 1982 to 1985. Analysis of surface water quality reviled loading of nutrients from nonpoint source pollution associated with agricultu...

When and where to intervene? Coastal nutrient loading, groundwater travel times, and estuary dynamics

EPA Science Inventory

There is often a difference between the timing of an intervention in a natural system and the resultant impact. Delays in the transport of pollutants from sources, inertia in the effects of policy on economic actors, and long-term memory in natural systems, turn environmental man...

A COMPREHENSIVE NONPOINT SOURCE FIELD STUDY FOR SEDIMENT, NUTRIENTS, AND PATHOGENS IN THE SOUTH FORK BROAD RIVER WATERSHED IN NORTHEAST GEORGIA

EPA Science Inventory

This technical report provides a description of the field project design, quality control, the sampling protocols and analysis methodology used, and standard operating procedures for the South Fork Broad River Watershed (SFBR) Total Maximum Daily Load (TMDL) project. This watersh...

N and P as ultimate and proximate limiting nutrients in the northern Gulf of Mexico: implications for hypoxia reduction strategies

NASA Astrophysics Data System (ADS)

Fennel, Katja; Laurent, Arnaud

2018-05-01

The occurrence of hypoxia in coastal oceans is a long-standing and growing problem worldwide and is clearly linked to anthropogenic nutrient inputs. While the need for reducing anthropogenic nutrient loads is generally accepted, it is costly and thus requires scientifically sound nutrient-reduction strategies. Issues under debate include the relative importance of nitrogen (N) and phosphorus (P) as well as the magnitude of the reduction requirements. The largest anthropogenically induced hypoxic area in North American coastal waters (of 15 000 ± 5000 km2) forms every summer in the northern Gulf of Mexico where the Mississippi and Atchafalaya rivers deliver large amounts of freshwater and nutrients to the shelf. A 2001 plan for reducing this hypoxic area by nutrient management in the watershed called for a reduction of N loads. Since then evidence of P limitation during the time of hypoxia formation has arisen, and a dual nutrient-reduction strategy for this system has been endorsed. Here we report the first systematic analysis of the effects of single and dual nutrient load reductions from a spatially explicit physical-biogeochemical model for the northern Gulf of Mexico. The model has been shown previously to skillfully represent the processes important for hypoxic formation. Our analysis of an ensemble of simulations with stepwise reductions in N, P, and N and P loads provides insight into the effects of both nutrients on primary production and hypoxia, and it allows us to estimate what nutrient reductions would be required for single and dual nutrient-reduction strategies to reach the hypoxia target. Our results show that, despite temporary P limitation, N is the ultimate limiting nutrient for primary production in this system. Nevertheless, a reduction in P load would reduce hypoxia because primary production is P limited in the region where density stratification is conducive to hypoxia development, but reductions in N load have a bigger effect. Our simulations show that, at present loads, the system is almost saturated with N, in the sense that the sensitivity of primary production and hypoxia to N load is much lower than it would be at lower N loads. We estimate that reductions of 63±18 % in total N load or 48±21 % in total N and P load are necessary to reach a hypoxic area of 5000 km2, which is consistent with previous estimates from statistical regression models and highly simplified mechanistic models.

Physiological responses of the seagrass Thalassia hemprichii (Ehrenb.) Aschers as indicators of nutrient loading.

PubMed

Zhang, Jingping; Huang, Xiaoping; Jiang, Zhijian

2014-06-30

To select appropriate bioindicators for the evaluation of the influence of nutrients from human activities in a Thalassia hemprichii meadow, environmental variables and plant performance parameters were measured in Xincun Bay, Hainan Island, South China. Nutrient concentrations in the bay decreased along a gradient from west to southeast. Moreover, the nutrients decreased with an increase in the distance from the shore on the southern side of the bay. Among the candidate indicators, the P content of the tissues closely mirrored the two nutrient loading gradients. The epiphytic algae biomass and the N content in the tissues mirrored one of the two nutrient loading trends. The leaf length, however, exhibited a significant negative correlation with the nutrient gradients. We propose that changes in the P content of T. hemprichii, followed by epiphytic algae biomass and N content of the tissues, may be the useful indicators of nutrient loading to coastal ecosystems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Nutrient Loading and Algal Response in West Thompson Lake, Thompson, Connecticut, 2003-2005

USGS Publications Warehouse

Morrison, Jonathan; Colombo, Michael J.

2008-01-01

Water quality and nutrient loads were characterized for parts of the Quinebaug River and West Thompson Lake in northeastern Connecticut during 2003 to 2005. The West Thompson Lake watershed is a mainly forested watershed that receives treated municipal wastewater from several point sources in Massachusetts. The lake is a flood-control reservoir formed in 1966 by impoundment of the Quinebaug River. Median concentrations of total phosphorus in two inflow (upstream) and one outflow (downstream) sampling stations on the Quinebaug River were higher than the nutrient criteria recommended by the U.S. Environmental Protection Agency (USEPA) for rivers and streams in aggregate Ecoregion XIV. In general, concentrations of total phosphorus in West Thompson Lake also were above the nutrient criteria recommended by USEPA for lakes and impoundments in aggregate Ecoregion XIV. The trophic status of West Thompson Lake has changed since 1995 from a hypereutrophic lake to a eutrophic lake; however, the lake still has large algal blooms. These blooms are predominated by blue-green algae, with chlorophyll-a concentrations of more than 30 micrograms per liter and algal cell counts as high as 73,000 cells/mL. Water samples collected during the summer of 2005 identified phosphorus as the primary limiting nutrient early in the season, but algal growth is probably co-limited by phosphorus and nitrogen later in the season. Lake-bottom sediments were collected from several areas throughout the lake and ranged in thickness from less than 1 foot (ft) to more than 3 ft. Concentrations of phosphorus in sediments differed throughout the lake; the highest values were found in the middle of the lake. Concentrations of total phosphorus also increased from an average 1,800 milligrams per kilogram (mg/kg) in the upper layers of sediment to more than 6,000 mg/kg at depth in the sediment. Annual, seasonal, and monthly loads and yields of nutrients were calculated for the three sampling locations on the Quinebaug River to develop a nutrient mass-balance model (budget) for West Thompson Lake. The average annual yields of total phosphorus during 2000 to 2005 were 115 pounds per square mile per year (lb/mi2/yr) at Quinebaug (inflow station), 116 lb/mi2/yr at Red Bridge Road (inflow station), and 97.9 lb/mi2/yr at West Thompson (outflow station). The 18-percent decrease in the average annual yield of total phosphorus between the inflow station at Red Bridge Road and the outlet of West Thompson Lake at West Thompson indicates that a significant part of the phosphorus load is retained in the lake. Annual yields of total phosphorus at Quinebaug have decreased significantly since the 1980s, from 362 lb/mi2/yr (for 1981-1990) to 115 lb/mi2/yr (1996-2005). The annual net export of phosphorus in West Thompson Lake during water years 2000 to 2005 ranged from -36 percent (2005) to 1 percent (2002) of the incoming load. Seasonal mass-balance data for total phosphorus during the summers of 2000 to 2003, when streamflow was at or lower than normal, indicated a net export of phosphorus that ranged from 3.4 percent (2003) to 30.7 percent (2002) of the incoming load. During the summer of 2004, however, streamflows were much higher than normal, and there was a negative export of phosphorus in West Thompson Lake of -3.9 percent. The annual net export of nitrogen in West Thompson Lake during water years 2000 to 2005 ranged from -5 percent (2002) to 4 percent (2001) of the incoming load. No clear pattern was evident to relate total nitrogen export to seasonal variables or runoff. Removal of phosphorus during the summer by wastewater-treatment plants (WWTPs) in Massachusetts reduces the concentration and load of total phosphorus entering West Thompson Lake in the summer; however, the large amount of phosphorus retained in the lake during the other seasons, in addition to the phosphorus stored in the lake-bottom sediments, may become available to fuel algal blooms in the lake

Comparison of two methods for estimating discharge and nutrient loads from Tidally affected reaches of the Myakka and Peace Rivers, West-Central Florida

USGS Publications Warehouse

Levesque, V.A.; Hammett, K.M.

1997-01-01

The Myakka and Peace River Basins constitute more than 60 percent of the total inflow area and contribute more than half the total tributary inflow to the Charlotte Harbor estuarine system. Water discharge and nutrient enrichment have been identified as significant concerns in the estuary, and consequently, it is important to accurately estimate the magnitude of discharges and nutrient loads transported by inflows from both rivers. Two methods for estimating discharge and nutrient loads from tidally affected reaches of the Myakka and Peace Rivers were compared. The first method was a tidal-estimation method, in which discharge and nutrient loads were estimated based on stage, water-velocity, discharge, and water-quality data collected near the mouths of the rivers. The second method was a traditional basin-ratio method in which discharge and nutrient loads at the mouths were estimated from discharge and loads measured at upstream stations. Stage and water-velocity data were collected near the river mouths by submersible instruments, deployed in situ, and discharge measurements were made with an acoustic Doppler current profiler. The data collected near the mouths of the Myakka River and Peace River were filtered, using a low-pass filter, to remove daily mixed-tide effects with periods less than about 2 days. The filtered data from near the river mouths were used to calculate daily mean discharge and nutrient loads. These tidal-estimation-method values were then compared to the basin-ratio-method values. Four separate 30-day periods of differing streamflow conditions were chosen for monitoring and comparison. Discharge and nutrient load estimates computed from the tidal-estimation and basin-ratio methods were most similar during high-flow periods. However, during high flow, the values computed from the tidal-estimation method for the Myakka and Peace Rivers were consistently lower than the values computed from the basin-ratio method. There were substantial differences between discharges and nutrient loads computed from the tidal-estimation and basin-ratio methods during low-flow periods. Furthermore, the differences between the methods were not consistent. Discharges and nutrient loads computed from the tidal-estimation method for the Myakka River were higher than those computed from the basin-ratio method, whereas discharges and nutrients loads computed by the tidal-estimation method for the Peace River were not only lower than those computed from the basin-ratio method, but they actually reflected a negative, or upstream, net movement. Short-term tidal measurement results should be used with caution, because antecedent conditions can influence the discharge and nutrient loads. Continuous tidal data collected over a 1- or 2-year period would be necessary to more accurately estimate the tidally affected discharge and nutrient loads for the Myakka and Peace River Basins.

Hardening fertilization and nutrient loading of conifer seedlings

Treesearch

R. Kasten Dumroese

2003-01-01

Continuing to fertilize bareroot and container seedlings during the hardening process (from cessation of height growth until lifting) can improve seedling viability. The process of fertilizing during hardening has many names, but in the last decade a new term, nutrient loading, has come into use. The process of nutrient loading seedlings leads to luxury consumption...

Uncertainty in nutrient loads from tile drained landscapes: Effect of sampling frequency, calculation algorithm, and compositing strategies

USDA-ARS?s Scientific Manuscript database

Accurate estimates of annual nutrient loads are required to evaluate trends in water quality following changes in land use or management and to calibrate and validate water quality models. While much emphasis has been placed on understanding the uncertainty of watershed-scale nutrient load estimates...

FECAL BACTERIA SOURCE TRACKING AND BACTEROIDES SPP. HOST SPECIES SPECIFICITY ANALYSIS

EPA Science Inventory

Point and non-point pollution sources of fecal pollution on a watershed adversely impact the quality of drinking source waters and recreational waters. States are required to develop total maximum daily loads (TMDLs) and devise best management practices (BMPs) to reduce the po...

Characteristics of Nitrogen and Phosphorus Effluent Load from a Paddy-field District Implementing Crop Rotation

NASA Astrophysics Data System (ADS)

Hama, Takehide; Aoki, Takeru; Osuga, Katsuyuki; Nakamura, Kimihito; Sugiyama, Sho; Kawashima, Shigeto

Implementation of collective crop rotation in a paddy-field district may increase nutrients effluent load. We have investigated a paddy-field district implementing collective crop rotation of wheat and soybeans, measured temporal variations in nutrients concentration of drainage water and the amount of discharged water for consecutive three years, and estimated nutrients effluent load from the district during the irrigation and non-irrigation periods. As a result, the highest concentration of nutrients was observed during the non-irrigation period in every investigation year. It was shown that high nutrients concentration of drainage water during the non-irrigation period was caused by runoff of fertilizer applied to wheat because the peaks of nutrients concentration of drainage water were seen in rainy days after fertilizer application in the crop-rotation field. The effluent load during the non-irrigation periods was 16.9-22.1 kgN ha-1 (nitrogen) and 0.84-1.42 kgP ha-1 (phosphorus), which respectively accounted for 46-66% and 27-54% of annual nutrients effluent load.

Impacts of housing development on nutrients flow along canals in a peri-urban area of Bangkok, Thailand.

PubMed

Honda, R; Hara, Y; Sekiyama, M; Hiramatsu, A

2010-01-01

Change of nutrients load and flow according to land-use change induced by housing development was investigated in Bang Yai, Nonthaburi, Thailand, which located in the peri-urban area of Bangkok. Each house in the newly developed residential community was regulated to be equipped with a septic tank to collect night soil. However, greywater and leachate from the septic tank was collected by a community sewage system and discharged into the canals with insufficient treatment, while the canals still function as infrastructure for irrigation and transportation. In the study area, built-up area became 1.4 times and agricultural fields decreased by 13% from 2003 until 2007. Total nutrients load to the canals was increased by 25% as nitrogen and 14% as phosphorus according to the increase of built-up area. Net nutrients load from agricultural fields was largely set off when we evaluated nutrients inflow from the canals to the agricultural field through irrigation. Consequently, nutrients load from domestic wastewater accounted most of net nutrients load into the canal.

Modeling the Relative Importance of Nutrient and Carbon Loads, Boundary Fluxes, and Sediment Fluxes on Gulf of Mexico Hypoxia.

PubMed

Feist, Timothy J; Pauer, James J; Melendez, Wilson; Lehrter, John C; DePetro, Phillip A; Rygwelski, Kenneth R; Ko, Dong S; Kreis, Russell G

2016-08-16

The Louisiana continental shelf in the northern Gulf of Mexico experiences bottom water hypoxia in the summer. In this study, we applied a biogeochemical model that simulates dissolved oxygen concentrations on the shelf in response to varying riverine nutrient and organic carbon loads, boundary fluxes, and sediment fluxes. Five-year model simulations demonstrated that midsummer hypoxic areas were most sensitive to riverine nutrient loads and sediment oxygen demand from settled organic carbon. Hypoxic area predictions were also sensitive to nutrient and organic carbon fluxes from lateral boundaries. The predicted hypoxic area decreased with decreases in nutrient loads, but the extent of change was influenced by the method used to estimate model boundary concentrations. We demonstrated that modeling efforts to predict changes in hypoxic area on the continental shelf in relationship to changes in nutrients should include representative boundary nutrient and organic carbon concentrations and functions for estimating sediment oxygen demand that are linked to settled organic carbon derived from water-column primary production. On the basis of our model analyses using the most representative boundary concentrations, nutrient loads would need to be reduced by 69% to achieve the Gulf of Mexico Nutrient Task Force Action Plan target hypoxic area of 5000 km(2).

Sources and sinks of nitrogen and phosphorus to a deep, oligotrophic lake, Lake Crescent, Olympic National Park, Washington

USGS Publications Warehouse

Moran, P.W.; Cox, S.E.; Embrey, S.S.; Huffman, R.L.; Olsen, T.D.; Fradkin, S.C.

2012-01-01

Lake Crescent, in Olympic National Park in the northwest corner of Washington State is a deep-water lake renowned for its pristine water quality and oligotrophic nature. To examine the major sources and sinks of nutrients (as total nitrogen, total phosphorus, and dissolved nitrate), a study was conducted in the Lake Crescent watershed. The study involved measuring five major inflow streams, the Lyre River as the major outflow, recording weather and climatic data, coring lake bed sediment, and analyzing nutrient chemistry in several relevant media over 14 months. Water samples for total nitrogen, total phosphorous, and dissolved nitrate from the five inflow streams, the outlet Lyre River, and two stations in the lake were collected monthly from May 2006 through May 2007. Periodic samples of shallow water from temporary sampling wells were collected at numerous locations around the lake. Concentrations of nutrients detected in Lake Crescent and tributaries were then applied to the water budget estimates to arrive at monthly and annual loads from various environmental components within the watershed. Other sources, such as leaf litter, pollen, or automobile exhaust were estimated from annual values obtained from various literature sources. This information then was used to construct a nutrient budget for total nitrogen and total phosphorus. The nitrogen budget generally highlights vehicle traffic-diesel trucks in particular-along U.S. Highway 101 as a potential major anthropogenic source of nitrogen compounds in the lake. In contrast, contribution of nitrogen compounds from onsite septic systems appears to be relatively minor related to the other sources identified.

Nutrients and clam contamination by Escherichia coli in a meso-tidal coastal lagoon: Seasonal variation in counter cycle to external sources.

PubMed

Botelho, Maria João; Soares, Florbela; Matias, Domitília; Vale, Carlos

2015-07-15

The clam Ruditapes decussatus was transplanted from a natural recruitment area of Ria Formosa to three sites, surveyed for nutrients in water and sediments. Specimens were sampled monthly for determination of Escherichia coli, condition index and gonadal index. Higher nutrient values in low tide reflect drainage, anthropogenic sources or sediment regeneration, emphasising the importance of water mixing in the entire lagoon driven by the tide. Despite the increase of effluent discharges in summer due to tourism, nutrient concentrations and E. coli in clams were lower in warmer periods. The bactericide effect of temperature and solar radiation was better defined in clams from the inlet channel site than from sites closer to urban effluents. High temperature in summer and torrential freshwater inputs to Ria Formosa may anticipate climate change scenarios for south Europe. Seasonal variation of nutrients and clam contamination may thus point to possible alterations in coastal lagoons and their ecosystem services. Copyright © 2015. Published by Elsevier Ltd.

Tracing suspended sediment sources in the Upper Sangamon River Basin using conservative and non-conservative tracers

NASA Astrophysics Data System (ADS)

Yu, M.; Rhoads, B. L.; Stumpf, A.

2015-12-01

As the awareness of water pollution, eutrophication and other water related environmental concerns grows, the significance of sediment in the transport of nutrients and contaminants from agricultural areas to streams has received increasing attention. Both the physical and geochemical properties of suspended sediment are strongly controlled by sediment sources. Thus, tracing sources of suspended sediment in watersheds is important for the design of management practices to reduce sediment loads and contributions of sediment-adsorbed nutrients from agricultural areas to streams. However, the contributions of different sediment sources to suspended sediment loads within intensively managed watersheds in the Midwest still remain insufficiently explored. This study aims to assess the provenance of suspended sediment and the relation between channel morphology and production of suspended sediment in the Upper Sangamon River Basin, Illinois, USA. The 3,690-km2 Upper Sangamon River Basin is characterized by low-relief, agricultural lands dominated by row-crop agriculture. Sediment source samples were collected in the Saybrook from five potential sources: farmland, forests, floodplains, river banks, and grasslands. Event-based and accumulated suspended sediment samples were collected by ISCO automatic pump samplers and in situ suspended sediment samplers and from the stream at watershed outlet. A quantitative geochemical fingerprinting technique, combining statistically verified multicomponent signatures and an un-mixing model, was employed to estimate the relative contributions of sediment from five potential sources to the suspended sediment loads. Organic matter content, trace elements, and radionuclides from soil samples were used as potential tracers. Our preliminary results indicate that the majority of suspended sediment is derived from floodplains in the downstream portions of the watersheds, while only minor amounts of suspended sediment are derived from upland areas and banks. These results suggest that floodplain erosion during high flow events contributes to the suspended sediment.

From salmon to shad: Shifting sources of marine-derived nutrients in the Columbia River Basin

USGS Publications Warehouse

Haskell, Craig A.

2018-01-01

Like Pacific salmon (Oncorhynchus spp.), nonnative American shad (Alosa sapidissima) have the potential to convey large quantities of nutrients between the Pacific Ocean and freshwater spawning areas in the Columbia River Basin (CRB). American shad are now the most numerous anadromous fish in the CRB, yet the magnitude of the resulting nutrient flux owing to the shift from salmon to shad is unknown. Nutrient flux models revealed that American shad conveyed over 15,000 kg of nitrogen (N) and 3,000 kg of phosphorus (P) annually to John Day Reservoir, the largest mainstem reservoir in the lower Columbia River. Shad were net importers of N, with juveniles and postspawners exporting just 31% of the N imported by adults. Shad were usually net importers of P, with juveniles and postspawners exporting 46% of the P imported by adults on average. American shad contributed <0.2% of the total annual P load into John Day Reservoir, but during June when most adult shad are migrating into John Day Reservoir, they contributed as much as 2.0% of the P load. Nutrient inputs by American shad were similar to current but far less than historical inputs of Pacific salmon owing to their smaller size. Given the relatively high background P levels and low retention times in lower Columbia River reservoirs, it is unlikely that shad marine-derived nutrients affect nutrient balances or food web productivity through autotrophic pathways. However, a better understanding of shad spawning aggregations in the CRB is needed.

Estimation of constituent concentrations, densities, loads, and yields in lower Kansas River, northeast Kansas, using regression models and continuous water-quality monitoring, January 2000 through December 2003

USGS Publications Warehouse

Rasmussen, Teresa J.; Ziegler, Andrew C.; Rasmussen, Patrick P.

2005-01-01

The lower Kansas River is an important source of drinking water for hundreds of thousands of people in northeast Kansas. Constituents of concern identified by the Kansas Department of Health and Environment (KDHE) for streams in the lower Kansas River Basin include sulfate, chloride, nutrients, atrazine, bacteria, and sediment. Real-time continuous water-quality monitors were operated at three locations along the lower Kansas River from July 1999 through September 2004 to provide in-stream measurements of specific conductance, pH, water temperature, turbidity, and dissolved oxygen and to estimate concentrations for constituents of concern. Estimates of concentration and densities were combined with streamflow to calculate constituent loads and yields from January 2000 through December 2003. The Wamego monitoring site is located 44 river miles upstream from the Topeka monitoring site, which is 65 river miles upstream from the DeSoto monitoring site, which is 18 river miles upstream from where the Kansas River flows into the Missouri River. Land use in the Kansas River Basin is dominated by grassland and cropland, and streamflow is affected substantially by reservoirs. Water quality at the three monitoring sites varied with hydrologic conditions, season, and proximity to constituent sources. Nutrient and sediment concentrations and bacteria densities were substantially larger during periods of increased streamflow, indicating important contributions from nonpoint sources in the drainage basin. During the study period, pH remained well above the KDHE lower criterion of 6.5 standard units at all sites in all years, but exceeded the upper criterion of 8.5 standard units annually between 2 percent of the time (Wamego in 2001) and 65 percent of the time (DeSoto in 2003). The dissolved oxygen concentration was less than the minimum aquatic-life-support criterion of 5.0 milligrams per liter less than 1 percent of the time at all sites. Dissolved solids, a measure of the dissolved material in water, exceeded 500 milligrams per liter about one-half of the time at the three Kansas River sites. Larger dissolved-solids concentrations upstream likely were a result of water inflow from the highly mineralized Smoky Hill River that is diluted by tributary flow as it moves downstream. Concentrations of total nitrogen and total phosphorus at the three monitoring sites exceeded the ecoregion water-quality criteria suggested by the U.S. Environmental Protection Agency during the entire study period. Median nitrogen and phosphorus concentrations were similar at all three sites, and nutrient load increased moving from the upstream to downstream sites. Total nitrogen and total phosphorus yields were nearly the same from site to site indicating that nutrient sources were evenly distributed throughout the lower Kansas River Basin. About 11 percent of the total nitrogen load and 12 percent of the total phosphorus load at DeSoto during 2000-03 originated from wastewater-treatment facilities. Escherichia coli bacteria densities were largest at the middle site, Topeka. On average, 83 percent of the annual bacteria load at DeSoto during 2000-03 occurred during 10 percent of the time, primarily in conjunction with runoff. The average annual sediment loads at the middle and downstream monitoring sites (Topeka and DeSoto) were nearly double those at the upstream site (Wamego). The average annual sediment yield was largest at Topeka. On average, 64 percent of the annual suspended-sediment load at DeSoto during 2000-03 occurred during 10 percent of the time. Trapping of sediment by reservoirs located on contributing tributaries decreases transport of sediment and sediment-related constituents. The average annual suspended-sediment load in the Kansas River at DeSoto during 2000-03 was estimated at 1.66 million tons. An estimated 13 percent of this load consisted of sand-size particles, so approximately 216,000 tons of sand were transported

Estimating nitrate emissions to surface water at regional and national scale: comparison of models using detailed regional and national-wide databases (France)

NASA Astrophysics Data System (ADS)

Dupas, R.; Gascuel-Odoux, C.; Durand, P.; Parnaudeau, V.

2012-04-01

The European Union (EU) Water Framework Directive (WFD) requires River Basin District managers to carry out an analysis of nutrient pressures and impacts, in order to evaluate the risk of water bodies failing to reach "good ecological status" and to identify those catchments where prioritized nonpoint-source control measures should be implemented. A model has been developed to estimate nitrate nonpoint-source emissions to surface water, using readily available data in France. It was inspired from US model SPARROW (Smith al., 1997) and European model GREEN (Grizzetti et al., 2008), i.e. statistical approaches consisting of linking nitrogen sources and catchments' land and rivers characteristics. The N-nitrate load (L) at the outlet of a catchment is expressed as: L= R*(B*Lsgw+Ldgw+PS)-denitlake Where denitlake is a denitrification factor for lakes and reservoirs, Lsgw is the shallow groundwater discharge to streams (derived from the base flow index and N surplus in kgN.ha-1.yr-1), Ldgw is the deep groundwater discharge to streams (derived from total runoff, the base flow index and deep groundwater N concentration), PS is point sources from domestic and industrial origin (kgN.ha-1.yr-1) and R and B are the river system and basin reduction factor, respectively. Besides calibrating and evaluating the model at a national scale, its predictive quality was compared with those of regionalized models in Brittany (Western France) and in the Seine river basin (Paris basin), where detailed regional databases are available. The national-scale model proved to provide robust predictions in most conditions encountered in France, as it fitted observed N-nitrate load with an efficiency of 0.69. Regionalization of the model reduced the standard error in the prediction of N-nitrate loads by about 19 Hence, the development of regionalized models should be advocated only after the trade-off between improvement of fit and degradation of parameters' estimation has come under scrutiny.

Sources and pathways of nutrients in the semi-arid region of Beijing-Tianjin, China.

PubMed

Pernet-Coudrier, Benoît; Qi, Weixiao; Liu, Huijuan; Müller, Beat; Berg, Michael

2012-05-15

Semiarid regions worldwide are particularly prone to eutrophication, which causes immense ecological and economic problems. One region that is in transition and requires systematic research for effective intervention is the dry landscape of Beijing-Tianjin (P. R. China). We investigated the sources and spatiotemporal loads of nitrogen and phosphorus species over a one-year period in the Haihe catchment that drains the megacity of Beijing. Although wastewater treatment was improved in recent years, the rivers were heavily contaminated by 0.3-5.3 mg P L(-1) and 3.0-49 mg N L(-1), with toxic levels of nitrite (≥1 mg NO(2)-N L(-1)) and ammonia (≥0.6 mg NH(3)-N L(-1)). The average NH(4)(+) (16.9 mg N L(-1)) increased by 160% compared to 1996-levels. Mass fluxes and δ(15)N-signatures revealed that nutrients originated almost exclusively from sewage. Furthermore, the water balance demonstrated that >90% of the polluted river water was diverted for irrigation, thereby threatening food safety and groundwater quality. Per capita loads of 1.42 kg N/yr and 115 g P/yr were comparable to the peak discharges typical of Europe and the United States in 1970-1990, but concentrations were 2-3 times higher in the Beijing-Tianjin region. Our research identified sewage as the predominant nutrient source in this semiarid region, which suggests that state-of-the-art wastewater treatment would drastically mitigate eutrophication and even more rapidly than was previously observed in Europe.

Sources and Pathways of Nutrients in the Semi-Arid Region of Beijing–Tianjin, China

PubMed Central

2012-01-01

Semiarid regions worldwide are particularly prone to eutrophication, which causes immense ecological and economic problems. One region that is in transition and requires systematic research for effective intervention is the dry landscape of Beijing-Tianjin (P. R. China). We investigated the sources and spatiotemporal loads of nitrogen and phosphorus species over a one-year period in the Haihe catchment that drains the megacity of Beijing. Although wastewater treatment was improved in recent years, the rivers were heavily contaminated by 0.3–5.3 mgP L–1 and 3.0–49 mgN L–1, with toxic levels of nitrite (≥1 mgNO2–N L–1) and ammonia (≥0.6 mgNH3–N L–1). The average NH4+ (16.9 mgN L–1) increased by 160% compared to 1996-levels. Mass fluxes and δ15N-signatures revealed that nutrients originated almost exclusively from sewage. Furthermore, the water balance demonstrated that >90% of the polluted river water was diverted for irrigation, thereby threatening food safety and groundwater quality. Per capita loads of 1.42 kgN/yr and 115 gP/yr were comparable to the peak discharges typical of Europe and the United States in 1970–1990, but concentrations were 2–3 times higher in the Beijing–Tianjin region. Our research identified sewage as the predominant nutrient source in this semiarid region, which suggests that state-of-the-art wastewater treatment would drastically mitigate eutrophication and even more rapidly than was previously observed in Europe. PMID:22401269

SOURCES AND TRANSFORMATIONS OF NITROGEN, CARBON, AND PHOSPHORUS IN THE POTOMAC RIVER ESTUARY

NASA Astrophysics Data System (ADS)

Pennino, M. J.; Kaushal, S.

2009-12-01

Global transport of nitrogen (N), carbon (C), and phosphorus (P) in river ecosystems has been dramatically altered due to urbanization. We examined the capacity of a major tributary of the Chesapeake Bay, the Potomac River, to transform carbon, nitrogen, and phosphorus inputs from the world’s largest advanced wastewater treatment facility (Washington D.C. Water and Sewer Authority). Surface water and effluent samples were collected along longitudinal transects of the Potomac River seasonally and compared to long-term interannual records of carbon, nitrogen, and phosphorus. Water samples from seasonal longitudinal transects were analyzed for dissolved organic and inorganic nitrogen and phosphorus, total organic carbon, and particulate carbon, nitrogen, and phosphorus. The source and quality of organic matter was characterized using fluorescence spectroscopy, excitation emission matrices (EEMs), and PARAFAC modeling. Sources of nitrate were tracked using stable isotopes of nitrogen and oxygen. Along the river network stoichiometric ratios of C, N, and P were determined across sites and related to changes in flow conditions. Land use data and historical water chemistry data were also compared to assess the relative importance of non-point sources from land-use change versus point-sources of carbon, nitrogen, and phosphorus. Preliminary data from EEMs suggested that more humic-like organic matter was important above the wastewater treatment plant, but more protein-like organic matter was present below the treatment plant. Levels of nitrate and ammonia showed increases within the vicinity of the wastewater treatment outfall, but decreased rapidly downstream, potentially indicating nutrient uptake and/or denitrification. Phosphate levels decreased gradually along the river with a small increase near the wastewater treatment plant and a larger increase and decrease further downstream near the high salinity zone. Total organic carbon levels show a small decrease downstream. Ecological stoichiometric ratios along the river indicate increases in C/N ratios downstream, but no corresponding trend with C/P ratios. The N/P ratios increased directly below the treatment plant and then decreased gradually downstream. The C/N/P ratios remained level until the last two sampling stations within 20 miles of the Chesapeake Bay, where there is a large increase. Despite large inputs, there may be large variations in sources and ecological stoichiometry along rivers and estuaries, and knowledge of these transformations will be important in predicting changes in the amounts, forms, and stoichiometry of nutrient loads to coastal waters.

Data-driven nutrient analysis and reality check: Human inputs, catchment delivery and management effects

NASA Astrophysics Data System (ADS)

Destouni, G.

2017-12-01

Measures for mitigating nutrient loads to aquatic ecosystems should have observable effects, e.g, in the Baltic region after joint first periods of nutrient management actions under the Baltic Sea Action Plan (BASP; since 2007) and the EU Water Framework Directive (WFD; since 2009). Looking for such observable effects, all openly available water and nutrient monitoring data since 2003 are compiled and analyzed for Sweden as a case study. Results show that hydro-climatically driven water discharge dominates the determination of waterborne loads of both phosphorus and nitrogen. Furthermore, the nutrient loads and water discharge are all similarly well correlated with the ecosystem status classification of Swedish water bodies according to the WFD. Nutrient concentrations, which are hydro-climatically correlated and should thus reflect human effects better than loads, have changed only slightly over the study period (2003-2013) and even increased in moderate-to-bad status waters, where the WFD and BSAP jointly target nutrient decreases. These results indicate insufficient distinction and mitigation of human-driven nutrient components by the internationally harmonized applications of both the WFD and the BSAP. Aiming for better general identification of such components, nutrient data for the large transboundary catchments of the Baltic Sea and the Sava River are compared. The comparison shows cross-regional consistency in nutrient relationships to driving hydro-climatic conditions (water discharge) for nutrient loads, and socio-economic conditions (population density and farmland share) for nutrient concentrations. A data-driven screening methodology is further developed for estimating nutrient input and retention-delivery in catchments. Its first application to nested Sava River catchments identifies characteristic regional values of nutrient input per area and relative delivery, and hotspots of much larger inputs, related to urban high-population areas.

40 CFR 406.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS GRAIN MILLS POINT SOURCE CATEGORY Corn Wet Milling Subcategory § 406.16 Pretreatment... new corn wet milling source to be discharged to the POTW (gallons per one hour for flow and pounds per day for BOD5 and TSS). Q = average existing waste load to POTW. R = average waste load for the new...

40 CFR 406.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2012 CFR

2012-07-01

... GUIDELINES AND STANDARDS GRAIN MILLS POINT SOURCE CATEGORY Corn Wet Milling Subcategory § 406.16 Pretreatment... new corn wet milling source to be discharged to the POTW (gallons per one hour for flow and pounds per day for BOD5 and TSS). Q = average existing waste load to POTW. R = average waste load for the new...

40 CFR 406.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS GRAIN MILLS POINT SOURCE CATEGORY Corn Wet Milling Subcategory § 406.16 Pretreatment... new corn wet milling source to be discharged to the POTW (gallons per one hour for flow and pounds per day for BOD5 and TSS). Q = average existing waste load to POTW. R = average waste load for the new...

Impact of Crop Conversions on Runoff and Sediment Output in the Lower Mississippi River Basin

NASA Astrophysics Data System (ADS)

Momm, H.; Bingner, R. L.; Elkadiri, R.; Yaraser, L.; Porter, W.

2017-12-01

Farming management practices influence sediment and agrochemical loads exiting fields and entering downstream water bodies. These practices impact multiple physical processes responsible for sediment and nutrient detachment, transport, and deposition. Recent changes in farming practices in the Southern United States coincide with increased grain production, replacing traditional crops such as cotton with corn and soybeans. To grow these crops in the South, adapted crop management practices are needed (irrigation, fertilizer, etc.). In this study, the impact of grain crop adoption on hydrologic processes and non-point source pollutant production is quantified. A watershed located in the Big Sunflower River drainage basin (14,179 km2) - a part of the greater Lower Mississippi River basin - was selected due to its economic relevance, historical agricultural output, and depiction of recent farming management trends. Estimates of runoff and sediment loads were produced using the U.S. Department of Agriculture supported Annualized Agriculture Non-Point Source Pollution (AnnAGNPS) watershed pollution and management model. Existing physical conditions during a 16-year period (2000-2015) were characterized using 3,992 sub-catchments and 1,602 concentrated flow paths. Algorithms were developed to integrate continuous land use/land cover information, variable spatio-temporal irrigation practices, and crop output yield in order to generate a total of 2,922 unique management practices and corresponding soil-disturbing operations. A simulation representing existing conditions was contrasted with simulations depicting alternatives of management, irrigation practices, and temporal variations in crop yield. Quantification of anthropogenic impacts to water quality and water availability at a watershed scale supports the development of targeted pollution mitigation and custom conservation strategies.

Estimated water and nutrient inflows and outflows, Lake Cochituate, eastern Massachusetts, 1977-79

USGS Publications Warehouse

Gay, F.B.

1984-01-01

Streamflow was the major source of water and nutrients (nitrogen and phosphorus) to Lake Cochituate, followed by ground water, and then precipitation during April 1978 through March 1979. Compared to all sources during that period, streams contributed 7,217 million gallons (a little over 82 percent) of water, 63 ,000 pounds (between 50 and 60 percent) of nitrogen, and 3,000 pounds (94 percent) of phosphorus. A little over 60 percent of all the water that entered Lake Cochituate flowed from Fisk Pond. This single source transported about 38,000 pounds of nitrogen and 2,000 pounds of phosphorus. Ground-water inflow to Lake Cochituate occurs along its shoreline except at the north end of Lake Cochituate 's North Pond where natural seepage from the lake is occurring and at locations on the lake 's Middle and South Ponds where municipal wells induce infiltration of lake water amounting to 1,228 million gallons for that period. Discharge of ground water to the lake was estimated to range from 462 to 816 million gallons and transported from 31,000 to 55,000 pounds of nitrogen and from 46 to 82 pounds of phosphorus. Bulk precipitation was estimated to contribute about the same volume of water to the lake as ground water but double its phosphorus load. However, the load of nitrogen, 8000 pounds, from bulk precipitation was the smallest of any source. (USGS)

Nutrient trends through time in Sweden's Baltic Drainage Area

NASA Astrophysics Data System (ADS)

Fischer, I.; Destouni, G.; Prieto, C.

2015-12-01

Changes in climate and land-use have and will continue to modify regional hydrology, in turn impacting environmental health, agricultural productivity and water resource quality and availability. The Baltic region is an area of interest as the coast spans nine countries- serving over 100 million people. The Baltic Sea contains one of the largest human caused hypoxic dead zones due to eutrophication driven by anthropogenic excess loading of nutrients. Policies to reduce these loads include also international directives and agreements, such as the EU Water Framework Directive, adopted in 2000 to protect and improve water quality throughout the European Union, and the Baltic Sea Action Plan under the Helsinki Commission aimed specifically at reducing the nutrient loading to and mitigating the eutrophication of the Baltic Sea. In light of these policies and amidst the number of studies on the Baltic Sea we ask, using the accessible nutrient and discharge data what does nutrient loading look like today? Are the most excessive loads going down? Observed nutrient and flow time series across Sweden allow for answering these questions, by spatial and temporal trend analysis of loads from various parts of Sweden to the Baltic Sea. Analyzing these observed time series in conjunction with the ecological health status classifications of the EU Water Framework Directive, allows in particular for answering the question if the loads into the water bodies with the poorest water quality, and from those to the Baltic Sea, are improving, being maintained or deteriorating. Such insight is required to contribute to relevant and efficient water and nutrient load management. Furthermore, empirically calculating nutrient loads, rather than only modeling, reveals that the water body health classification may not reflect what water bodies actually contribute the heaviest loads to the Baltic Sea. This work also underscores the importance of comprehensive analysis of all available data from long term monitoring programs over large spatial scales, including large water quality gradients, in order to assess and address water management problems of today and the future.

Greywater characterization and loadings - Physicochemical treatment to promote onsite reuse.

PubMed

Noutsopoulos, C; Andreadakis, A; Kouris, N; Charchousi, D; Mendrinou, P; Galani, A; Mantziaras, I; Koumaki, E

2018-06-15

Greywater is the wastewater produced in bathtubs, showers, hand basins, kitchen sinks, dishwashers and laundry machines. Segregation of greywater and blackwater and on site greywater treatment in order to promote its reuse for toilet flushing and/or garden irrigation is an interesting option especially in water deficient areas. The objective of this study was to characterize the different greywater sources in Greek households and to evaluate the performance of alternative physicochemical treatment systems to treat several types of greywater. Based on the results average daily greywater production was equal to 98 L per person per day and accounts for approximately 70-75% of the total household wastewater production (135 L per person per day). Among the different sources, laundry and kitchen sink are the main contributors to the total greywater load of organic carbon, suspended solids and surfactants, whereas dishwasher and bathroom greywater are the main sources of phosphorus and endocrine disrupting chemicals respectively. Depending on sources, greywater accounts for as low as 15% of the total wastewater load of organic carbon (in the case of light greywater sources), to as high as 74% of the total load organic load (in the case of the heavy greywater sources). On the other hand, the nutrients load of greywater is limited. The application of a physical treatment system consisting of coagulation, sedimentation, sand filtration, granular activated carbon filtration and disinfection can provide for a final effluent with high quality characteristics for onsite reuse, especially when treating light greywater. Copyright © 2017 Elsevier Ltd. All rights reserved.

Competition for nutrients and light: testing advances in resource competition with a natural phytoplankton community.

PubMed

Burson, Amanda; Stomp, Maayke; Greenwell, Emma; Grosse, Julia; Huisman, Jef

2018-05-01

A key challenge in ecology is to understand how nutrients and light affect the biodiversity and community structure of phytoplankton and plant communities. According to resource competition models, ratios of limiting nutrients are major determinants of species composition. At high nutrient levels, however, species interactions may shift to competition for light, which might make nutrient ratios less relevant. The "nutrient-load hypothesis" merges these two perspectives, by extending the classic model of competition for two nutrients to include competition for light. Here, we test five key predictions of the nutrient-load hypothesis using multispecies competition experiments. A marine phytoplankton community sampled from the North Sea was inoculated in laboratory chemostats provided with different nitrogen (N) and phosphorus (P) loads to induce either single resource limitation or co-limitation of N, P, and light. Four of the five predictions were validated by the experiments. In particular, different resource limitations favored the dominance of different species. Increasing nutrient loads caused changes in phytoplankton species composition, even if the N:P ratio of the nutrient loads remained constant, by shifting the species interactions from competition for nutrients to competition for light. In all treatments, small species became dominant whereas larger species were competitively excluded, supporting the common view that small cell size provides a competitive advantage under resource-limited conditions. Contrary to expectation, all treatments led to coexistence of diatoms, cyanobacteria and green algae, resulting in a higher diversity of species than predicted by theory. Because the coexisting species comprised three phyla with different photosynthetic pigments, we speculate that niche differentiation in the light spectrum might play a role. Our results show that mechanistic resource competition models that integrate nutrient-based and light-based approaches provide an important step forward to understand and predict how changing nutrient loads affect community composition. © 2018 The Authors Ecology published by Wiley Periodicals, Inc. on behalf of Ecological Society of America.

Aquatic macrophytes can be used for wastewater polishing but not for purification in constructed wetlands

NASA Astrophysics Data System (ADS)

Tang, Yingying; Harpenslager, Sarah F.; van Kempen, Monique M. L.; Verbaarschot, Evi J. H.; Loeffen, Laury M. J. M.; Roelofs, Jan G. M.; Smolders, Alfons J. P.; Lamers, Leon P. M.

2017-02-01

The sequestration of nutrients from surface waters by aquatic macrophytes and sediments provides an important service to both natural and constructed wetlands. While emergent species take up nutrients from the sediment, submerged and floating macrophytes filter nutrients directly from the surface water, which may be more efficient in constructed wetlands. It remains unclear, however, whether their efficiency is sufficient for wastewater purification and how plant species and nutrient loading affects nutrient distribution over plants, water and sediment. We therefore determined nutrient removal efficiencies of different vegetation (Azolla filiculoides, Ceratophyllum demersum and Myriophyllum spicatum) and sediment types (clay, peaty clay and peat) at three nutrient input rates, in a full factorial, outdoor mesocosm experiment. At low loading (0.43 mg P m-2 d-1), plant uptake was the main pathway (100 %) for phosphorus (P) removal, while sediments showed a net P release. A. filiculoides and M. spicatum showed the highest biomass production and could be harvested regularly for nutrient recycling, whereas C. demersum was outcompeted by spontaneously developing macrophytes and algae. Higher nutrient loading only stimulated A. filiculoides growth. At higher rates ( ≥ 21.4 mg P m-2 d-1), 50-90 % of added P ended up in sediments, with peat sediments becoming more easily saturated. For nitrogen (N), 45-90 % was either taken up by the sediment or lost to the atmosphere at loadings ≥ 62 mg N m-2 d-1. This shows that aquatic macrophytes can indeed function as an efficient nutrient filter but only for low loading rates (polishing) and not for high rates (purification). The outcome of this controlled study not only contributes to our understanding of nutrient dynamics in constructed wetlands but also shows the differential effects of wetland sediment types and plant species. Furthermore, the acquired knowledge may benefit the application of macrophyte harvesting to remove and recycle nutrients from both constructed wetlands and nutrient-loaded natural wetlands.

Hydroponic potato production on nutrients derived from anaerobically-processed potato plant residues

NASA Astrophysics Data System (ADS)

Mackowiak, C. L.; Stutte, G. W.; Garland, J. L.; Finger, B. W.; Ruffe, L. M.

1997-01-01

Bioregenerative methods are being developed for recycling plant minerals from harvested inedible biomass as part of NASA's Advanced Life Support (ALS) research. Anaerobic processing produces secondary metabolites, a food source for yeast production, while providing a source of water soluble nutrients for plant growth. Since NH_4-N is the nitrogen product, processing the effluent through a nitrification reactor was used to convert this to NO_3-N, a more acceptable form for plants. Potato (Solanum tuberosum L.) cv. Norland plants were used to test the effects of anaerobically-produced effluent after processing through a yeast reactor or nitrification reactor. These treatments were compared to a mixed-N treatment (75:25, NO_3:NH_4) or a NO_3-N control, both containing only reagent-grade salts. Plant growth and tuber yields were greatest in the NO_3-N control and yeast reactor effluent treatments, which is noteworthy, considering the yeast reactor treatment had high organic loading in the nutrient solution and concomitant microbial activity.

Submarine groundwater discharge and nutrient loadings in Tolo Harbor, Hong Kong using multiple geotracer-based models, and their implications of red tide outbreaks.

PubMed

Luo, Xin; Jiao, Jiu Jimmy

2016-10-01

Multiple tracers, including radium quartet, (222)Rn and silica are used to quantify submarine groundwater discharge (SGD) into Tolo Harbor, Hong Kong in 2005 and 2011. Five geotracer models based on the end member model of (228)Ra and salinity and mass balance models of (226)Ra, (228)Ra, (222)Rn, and silica were established and all the models lead to an estimate of the SGD rate of the same order of magnitude. In 2005 and 2011, respectively, the averaged SGD based on these models is estimated to be ≈ 5.42 cm d(-1) and ≈2.66 cm d(-1), the SGD derived DIN loadings to be 3.5 × 10(5) mol d(-1) and 1.5 × 10(5) mol d(-1), and DIP loadings to be 6.2 × 10(3) mol d(-1) and 1.1 × 10(3) mol d(-1). Groundwater borne nutrients are 1-2 orders of magnitude larger than other nutrient sources and the interannual variation of nutrient concentration in the embayment is more influenced by the SGD derived loadings. Annual DIP concentrations in the harbor water is positively correlated with the precipitation and annual mean tidal range, and negatively correlated with evapotranspiration from 2000 to 2013. Climatologically driven SGD variability alters the SGD derived DIP loadings in this phosphate limited environment and may be the causative factor of interannual variability of red tide outbreaks from 2000 to 2013. Finally, a conceptual model is proposed to characterize the response of red tide outbreaks to climatological factors linked by SGD. The findings from this study shed light on the prediction of red tide outbreaks and coastal management of Tolo Harbor and similar coastal embayments elsewhere. Copyright © 2016 Elsevier Ltd. All rights reserved.

Water-quality assessment of White River between Lake Sequoyah and Beaver Reservoir, Washington County, Arkansas

USGS Publications Warehouse

Terry, J.E.; Morris, E.E.; Bryant, C.T.

1982-01-01

The Arkansas Department of Pollution Control and Ecology and U.S. Geological Survey conducted a water quality assessment be made of the White River and, that a steady-state digital model be calibrated and used as a tool for simulating changes in nutrient loading. The city of Fayetteville 's wastewater-treatment plant is the only point-source discharger of waste effluent to the river. Data collected during synoptic surveys downstream from the wastewater-treatment plan indicate that temperature, dissolved oxygen, dissolved solids, un-ionized ammonia, total phosphorus, and floating solids and depositable materials did not meet Arkansas stream standards. Nutrient loadings below the treatment plant result in dissolved oxygen concentrations as low as 0.0 milligrams per liter. Biological surveys found low macroinvertebrate organism diversity and numerous dead fish. Computed dissolved oxygen deficits indicate that benthic demands are the most significant oxygen sinks in the river downstream from the wastewater-treatment plant. Benthic oxygen demands range from 2.8 to 11.0 grams per meter squared per day. Model projections indicate that for 7-day, 10-year low-flow conditions and water temperature of 29 degrees Celsius, daily average dissolved oxygen concentrations of 6.0 milligrams per liter can be maintained downstream from the wastewater-treatment plant if effluent concentrations of ultimate carbonaceous biochemical oxygen demand and ammonia nitrogen are 7.5 (5.0 5-day demand) and 2 milligrams per liter respectively. Model sensitivity analysis indicate that dissolved oxygen concentrations were most sensitive to changes in stream temperature. (USGS)

Nutrients, Select Pesticides, and Suspended Sediment in the Karst Terrane of the Sinking Creek Basin, Kentucky, 2004-06

USGS Publications Warehouse

Crain, Angela S.

2010-01-01

This report presents the results of a study by the U.S. Geological Survey, in cooperation with the Kentucky Department of Agriculture, on nutrients, select pesticides, and suspended sediment in the karst terrane of the Sinking Creek Basin. Streamflow, nutrient, select pesticide, and suspended-sediment data were collected at seven sampling stations from 2004 through 2006. Concentrations of nitrite plus nitrate ranged from 0.21 to 4.9 milligrams per liter (mg/L) at the seven stations. The median concentration of nitrite plus nitrate for all stations sampled was 1.6 mg/L. Total phosphorus concentrations were greater than 0.1 mg/L, the U.S. Environmental Protection Agency's recommended maximum concentration, in 45 percent of the samples. Concentrations of orthophosphates ranged from less than 0.006 to 0.46 mg/L. Concentrations of nutrients generally were larger during spring and summer months, corresponding to periods of increased fertilizer application on agricultural lands. Concentrations of suspended sediment ranged from 1.0 to 1,490 mg/L at the seven stations. Of the 47 pesticides analyzed, 14 were detected above the adjusted method reporting level of 0.01 micrograms per liter (mug/L). Although these pesticides were detected in water-quality samples, they generally were found at less than part-per-billion concentrations. Atrazine was the only pesticide detected at concentrations greater than U.S. Environmental Protection Agency drinking water standard of 3 mug/L, and the maximum detected concentration was 24.6 mug/L. Loads and yields of nutrients, selected pesticides, and suspended sediment were estimated at two mainstream stations on Sinking Creek, a headwater station (Sinking Creek at Rosetta) and a station at the basin outlet (Sinking Creek near Lodiburg). Mean daily streamflow data were available for the estimation of loads and yields from a stream gage at the basin outlet station; however, only periodic instantaneous flow measurements were available for the headwaters station; mean daily flows at the headwater station were, therefore, estimated using a mathematical record-extension technique known as the Maintenance of Variance-Extension, type 1 (MOVE.1). The estimation of mean daily streamflows introduced a large amount of uncertainty into the loads and yields estimates at the headwater station. Total estimated loads of select (five most commonly detected) pesticides from the Sinking Creek Basin were about 0.01 to 1.2 percent of the estimated application, indicating pesticides possibly are retained within the watershed. Mean annual loads [(in/lb)/yr] for nutrients and suspended sediment were estimated at the two Sinking Creek mainstem sampling stations. The relation between estimated and measured instantaneous loads of nitrite plus nitrate at the Sinking Creek near Lodiburg station indicate a reasonably tight distribution over the range of loads. The model for loads of nitrite plus nitrate at the Sinking Creek at Rosetta station indicates small loads were overestimated and underestimated. Relations between estimated and measured loads of total phosphorus and orthophosphate at both Sinking Creek mainstem stations showed similar patterns to the loads of nitrite plus nitrate at each respective station. The estimated mean annual load of suspended sediment is about 14 times larger at the Sinking Creek near Lodiburg station than at the Sinking Creek near Rosetta station. Estimated yields of nutrients and suspended sediment increased from the headwater to downstream monitoring stations on Sinking Creek. This finding suggests that sources of nutrients and suspended sediment are not evenly distributed throughout the karst terrane of the Sinking Creek Basin. Yields of select pesticides generally were similar from the headwater to downstream monitoring stations. However, the estimated yield of atrazine was about five times higher at the downstream station on Sinking Creek than at the headwater station on Sinking Creek.

Complete nutrient content of four species of commercially available feeder insects fed enhanced diets during growth.

PubMed

Finke, Mark D

2015-11-01

Commercially raised feeder insects used to feed captive insectivores are a good source of many nutrients but are deficient in several key nutrients. Current methods used to supplement insects include dusting and gut-loading. Here, we report on the nutrient composition of four species of commercially raised feeder insects fed a special diet to enhance their nutrient content. Crickets, mealworms, superworms, and waxworms were analyzed for moisture, crude protein, fat, ash, acid detergent fiber, total dietary fiber, minerals, amino acids, fatty acids, vitamins, taurine, carotenoids, inositol, and cholesterol. All four species contained enhanced levels of vitamin E and omega 3 fatty acids when compared to previously published data for these species. Crickets, superworms, and mealworms contained β-carotene although using standard conversion factors only crickets and superworms would likely contain sufficient vitamin A activity for most species of insectivores. Waxworms did not contain any detectable β-carotene but did contain zeaxanthin which they likely converted from dietary β-carotene. All four species contained significant amounts of both inositol and cholesterol. Like previous reports all insects were a poor source of calcium and only superworms contained vitamin D above the limit of detection. When compared to the nutrient requirements as established by the NRC for growing rats or poultry, these species were good sources of most other nutrients although the high fat and low moisture content of both waxworms and superworms means when corrected for energy density these two species were deficient in more nutrients than crickets or mealworms. These data show the value of modifying the diet of commercially available insects as they are growing to enhance their nutrient content. They also suggest that for most insectivores properly supplemented lower fat insects such as crickets, or smaller mealworms should form the bulk of the diet. © 2015 The Authors. Zoo Biology published by Wiley Periodicals, Inc.

Water quality functions of riparian forest buffers in Chesapeake bay watersheds

USGS Publications Warehouse

Lowrance, R.; Altier, L.S.; Newbold, J.D.; Schnabel, R.R.; Groffman, P.M.; Denver, J.M.; Correll, D.L.; Gilliam, J.W.; Robinson, J.L.; Brinsfield, R.B.; Staver, K.W.; Lucas, W.; Todd, A.H.

1997-01-01

Maryland, Virginia, and Pennsylvania, USA, have agreed to reduce nutrient loadings to Chesapeake Bay by 40% by the year 2000. This requires control of nonpoint sources of nutrients much of which comes from agriculture. Riparian forest buffer systems (RFBS) provide effective control of nonpoint source (NPS) pollution in some types of agricultural watersheds. Control of NPS pollution is dependent on the type of pollutant and the hydrologic connection between pollution sources, the RFBS, and the stream. Water quality improvements are most likely in areas of where most of the excess precipitation moves across, in, or near the root zone of the RFBS. In areas such as the Inner Coastal Plain and Piedmont watersheds with thin soils RFBS should retain 50%-90% of the total loading of nitrate in shallow groundwater sediment in surface runoff and total N in born surface runoff and groundwater. Retention of phosphorus is generally much less. In regions with deeper soils and/or greater regional groundwater recharge (such as parts of the Piedmont and the Valley and Ridge), RFBS water quality improvements are probably much less. The expected levels of pollutant control by RFBS are identified for each of nine physiographic provinces of the Chesapeake Bay Watershed. Issues related to of establishment sustainability, and management are also discussed.

Nutrient and phytoplankton analysis of a Mediterranean coastal area.

PubMed

Sebastiá, M T; Rodilla, M

2013-01-01

Identifying and quantifying the key anthropogenic nutrient input sources are essential to adopting management measures that can target input for maximum effect in controlling the phytoplankton biomass. In this study, three systems characterized by distinctive main nutrient sources were sampled along a Mediterranean coast transect. These sources were groundwater discharge in the Ahuir area, the Serpis river discharge in the Venecia area, and a submarine wastewater outfall 1,900 m from the coast. The study area includes factors considered important in determining a coastal area as a sensitive area: it has significant nutrient sources, tourism is a major source of income in the region, and it includes an area of high water residence time (Venecia area) which is affected by the harbor facilities and by wastewater discharges. We found that in the Ahuir and the submarine wastewater outfall areas, the effects of freshwater inputs were reduced because of a greater water exchange with the oligotrophic Mediterranean waters. On the other hand, in the Venecia area, the highest levels of nutrient concentration and phytoplankton biomass were attributed to the greatest water residence time. In this enclosed area, harmful dinoflagellates were detected (Alexandrium sp. and Dinophysis caudata). If the planned enlargement of the Gandia Harbor proceeds, it may increase the vulnerability of this system and provide the proper conditions of confinement for the dinoflagellate blooms' development. Management measures should first target phosphorus inputs as this is the most potential-limiting nutrient in the Venecia area and comes from a point source that is easier to control. Finally, we recommend that harbor environmental management plans include regular monitoring of water quality in adjacent waters to identify adverse phytoplankton community changes.

CHARACTERIZING SPATIAL AND TEMPORAL DYNAMICS: DEVELOPMENT OF A GRID-BASED WATERSHED MERCURY LOADING MODEL

EPA Science Inventory

A distributed grid-based watershed mercury loading model has been developed to characterize spatial and temporal dynamics of mercury from both point and non-point sources. The model simulates flow, sediment transport, and mercury dynamics on a daily time step across a diverse lan...

Trends in nutrients and suspended solids at the Fall Line of five tributaries to the Chesapeake Bay in Virginia, July 1988 through June 1995

USGS Publications Warehouse

Bell, C.F.; Belval, D.L.; Campbell, J.P.

1996-01-01

Water-quality samples were collected at the Fall Line of five tributaries to the Chesapeake Bay in Virginia during a 6- to 7-year period. The water-quality data were used to estimate loads of nutrients and suspended solids from these tributaries to the non-tidal part of Chesapeake Bay Basin and to identify trends in water quality. Knowledge of trends in water quality is required to assess the effectiveness of nutrient manage- ment strategies in the five basins. Multivariate log-linear regression and the seasonal Kendall test were used to estimate flow-adjusted trends in constituent concentration and load. Results of multivariate log-linear regression indicated a greater number of statistically significant trends than the seasonal Kendall test; how-ever, when both methods indicated a significant trend, both agreed on the direction of the trend. Interpre- tation of the trend estimates for this report was based on results of the parametric regression method. No significant trends in total nitrogen concentration were detected at the James River monitoring station from July 1988 through June 1995, though total Kjeldahl nitrogen concen- tration decreased slightly in base-flow samples. Total phosphorus concentration decreased about 29 percent at this station during the sampling period. Most of the decrease can be attributed to reductions in point-source phosphorus loads in 1988 and 1989, especially the phosphate detergent ban of 1988. No significant trends in total suspended solids were observed at the James River monitoring station, and no trends in runoff- derived constituents were interpreted for this river. Significant decreases were detected in concentrations of total nitrogen, total Kjeldahl nitrogen, dissolved nitrite-plus-nitrate nitrogen, and total suspended solids at the Rappahannock River monitoring station between July 1988 and June 1995. A similar downward trend in total phosphorus concentration was significant at the 90-percent confidence level, but not the 95-percent confidence level. These decreases can be attributed primarily to reductions in nonpoint nutrient and sediment loads, and may have been partially caused by implementation of best management practices on agricultural and silvicultural land. Flow-adjusted trends observed at the Appomattox, Pamunkey, and Mattaponi monitoring stations were more difficult to explain than those at the James and Rappahannock stations. Total Kjeldahl nitrogen and total phosphorus increased 16 and 23 percent, respectively, at the Appomattox River monitoring station from July 1989 through June 1995. Total phosphorus concentration increased about 46 percent at the Pamunkey River monitoring station between July 1989 and June 1995. At the Mattaponi River monitoring station, decreases in dissolved nitrite-plus-nitrate nitrogen were offset by increases in total Kjeldahl nitrogen, resulting in no net change in total nitrogen concentration from October 1989 through June 1995.

Modeling the Response of Nutrient Concentrations and Primary Productivity in Lake Michigan to Nutrient Loading Scenarios

EPA Science Inventory

A water quality model, LM3 Eutro, will be used to estimate the response of nutrient concentrations and primary productivity in Lake Michigan to nutrient loading scenarios. This work is part of a larger effort, the Future Midwestern landscapes study, that will estimate the produc...

Estimating Summer Nutrient Concentrations in Northeastern Lakes from SPARROW Load Predictions and Modeled Lake Depth and Volume

EPA Science Inventory

Global nutrient cycles have been altered by use of fossil fuels and fertilizers resulting in increases in nutrient loads to aquatic systems. In the United States, excess nutrients have been repeatedly reported as the primary cause of lake water quality impairments. Setting nutr...

A COMPARATIVE ANALYSIS OF NUTRIENT LOADING, NUTRIENT RETENTION AND NET ECOSYSTEM METABOLISM IN THREE TIDAL RIVER ESTUARIES DIFFERING PREDOMINATELY BY THEIR WATERSHED LAND USE TYPES.

EPA Science Inventory

Abstract and oral presentation for the Estuarine Research Federation Conference.

Estuarine retention of watershed nutrient loads, system-wide nutrient biogeochemical fluxes, and net ecosystem metabolism (NEM) were determined in three estuaries exhibiting differing magnitud...

A COMPREHENSIVE NONPOINT SOURCE FIELD STUDY FOR SEDIMENT, NUTRIENTS AND PATHOGENS IN THE SOUTH FORK BROAD RIVER WATERSHED, GEORGIA

EPA Science Inventory

There is an urgent need for EPA to develop protocols for establishing Total Maximum Daily Loads (TMDLs) in streams, lakes and estuaries. A cooperative TMDL field data collection project between ORD and Region 4 is ongoing in the South Fork Broad River Watershed (SFBR), a 245.18 ...

Quantitative identification of riverine nitrogen from point, direct runoff and base flow sources.

PubMed

Huang, Hong; Zhang, Baifa; Lu, Jun

2014-01-01

We present a methodological example for quantifying the contributions of riverine total nitrogen (TN) from point, direct runoff and base flow sources by combining a recursive digital filter technique and statistical methods. First, we separated daily riverine flow into direct runoff and base flow using a recursive digital filter technique; then, a statistical model was established using daily simultaneous data for TN load, direct runoff rate, base flow rate, and temperature; and finally, the TN loading from direct runoff and base flow sources could be inversely estimated. As a case study, this approach was adopted to identify the TN source contributions in Changle River, eastern China. Results showed that, during 2005-2009, the total annual TN input to the river was 1,700.4±250.2 ton, and the contributions of point, direct runoff and base flow sources were 17.8±2.8%, 45.0±3.6%, and 37.2±3.9%, respectively. The innovation of the approach is that the nitrogen from direct runoff and base flow sources could be separately quantified. The approach is simple but detailed enough to take the major factors into account, providing an effective and reliable method for riverine nitrogen loading estimation and source apportionment.

Pairing top-down and bottom-up approaches to analyze catchment scale management of water quality and quantity

NASA Astrophysics Data System (ADS)

Lovette, J. P.; Duncan, J. M.; Band, L. E.

2016-12-01

Watershed management requires information on the hydrologic impacts of local to regional land use, land cover and infrastructure conditions. Management of runoff volumes, storm flows, and water quality can benefit from large scale, "top-down" screening tools, using readily available information, as well as more detailed, "bottom-up" process-based models that explicitly track local runoff production and routing from sources to receiving water bodies. Regional scale data, available nationwide through the NHD+, and top-down models based on aggregated catchment information provide useful tools for estimating regional patterns of peak flows, volumes and nutrient loads at the catchment level. Management impacts can be estimated with these models, but have limited ability to resolve impacts beyond simple changes to land cover proportions. Alternatively, distributed process-based models provide more flexibility in modeling management impacts by resolving spatial patterns of nutrient source, runoff generation, and uptake. This bottom-up approach can incorporate explicit patterns of land cover, drainage connectivity, and vegetation extent, but are typically applied over smaller areas. Here, we first model peak flood flows and nitrogen loads across North Carolina's 70,000 NHD+ catchments using USGS regional streamflow regression equations and the SPARROW model. We also estimate management impact by altering aggregated sources in each of these models. To address the missing spatial implications of the top-down approach, we further explore the demand for riparian buffers as a management strategy, simulating the accumulation of nutrient sources along flow paths and the potential mitigation of these sources through forested buffers. We use the Regional Hydro-Ecological Simulation System (RHESSys) to model changes across several basins in North Carolina's Piedmont and Blue Ridge regions, ranging in size from 15 - 1,130 km2. The two approaches provide a complementary set of tools for large area screening, followed by smaller, more process based assessment and design tools.

Stable Isotope Evidence of Variation in Nitrogen Fixation by Cyanobacteria in Coastal Ecosystems

NASA Astrophysics Data System (ADS)

Paul, V.; Clementz, M.

2006-12-01

Increased nutrient loading via both natural and anthropogenic factors has been reported as one possible mechanism for the recent increase in the occurrence and intensity of harmful algal blooms (HAB) in coastal ecosystems. Influx of iron, phosphorous, and organic carbon have proven to be significant stimulating factors for HAB, since the benthic cyanobacteria that often make up these blooms are capable of nitrogen-fixation and require these nutrients for this process as well as photosynthesis. These cyanobacteria can switch to direct uptake of dissolved inorganic nitrogen (DIN), however, when concentrations are high enough to energetically favor this source, suggesting that high nitrogen input may also stimulate HAB. Given the distinct isotope differences between atmospheric N2 (0‰) and anthropogenic sources of DIN (>6‰), measurement of the δ15N composition of cyanobacteria can provide a means of gauging the relative significance of anthropogenic versus atmospheric nitrogen to the growth of these blooms. Likewise, the δ13C composition of these primary producers is controlled by the δ13C composition of the DIC, and can be a second tracer of anthropogenic influx into marine ecosystems. A combined approach using both isotope tracers was employed to determine the significance of anthropogenic nitrogen on HAB in subtropical/tropical coastal marine ecosystems. Samples of cyanobacteria and associated macroalgae were collected from three coastal sites in Guam (Facpi Point, Tanguisson, and Ypao Beach), one locality in Hawaii, and three sites in southern Florida (Pepper Park, Fort Lauderdale, Florida Keys). Following removal of marine carbonates via an acid rinse, the δ13C and δ15N values were determined for each species. Cyanobacterial δ15N values ranged from -2.3‰ to 7.7‰ with the highest values reported from sites in Guam. Only cyanobacteria sampled from Hawaii showed no isotope evidence of an anthropogenic source for nitrogen. A strong negative correlation between δ13C and δ15N values was detected for cyanobacteria from all sites. This correlation suggests that cyanobacteria are fixing nitrogen under oligotrophic conditions, but switch to using the readily available DIN when the nutrient load is high. The discovery of this relationship in three separate locations and among several different species of cyanobacteria suggests that this is a common feature of HAB and that nitrogen influx may have a more significant impact on the formation of these blooms than previously thought.

Spatial and temporal variations of loads and sources of total and dissolved Phosphorus in a set of rivers (Western France).

NASA Astrophysics Data System (ADS)

Legeay, Pierre-Louis; Moatar, Florentina; Gascuel-Odoux, Chantal; Gruau, Gérard

2015-04-01

In intensive agricultural regions with important livestock farming, long-term land application of Phosphorus (P) both as chemical fertilizer and animal wastes, have resulted in elevated P contents in soils. Since we know that high P concentrations in rivers is of major concern, few studies have been done at to assess the spatiotemporal variability of P loads in rivers and apportionment of point and nonpoint source in total loads. Here we focus on Brittany (Western France) where even though P is a great issue in terms of human and drinking water safety (cyano-toxins), environmental protection and economic costs for Brittany with regards to the periodic proliferations of cyanobacteria that occur every year in this region, no regional-scale systematic study has been carried out so far. We selected a set of small rivers (stream order 3-5) with homogeneous agriculture and granitic catchment. By gathering data from three water quality monitoring networks, covering more than 100 measurements stations, we provide a regional-scale quantification of the spatiotemporal variability of dissolved P (DP) and total P (TP) interannual loads from 1992 to 2012. Build on mean P load in low flows and statistical significance tests, we developed a new indicator, called 'low flow P load' (LFP-load), which allows us to determine the importance of domestic and industrial P sources in total P load and to assess their spatiotemporal variability compared to agricultural sources. The calculation and the map representation of DP and TP interannual load variations allow identification of the greatest and lowest P contributory catchments over the study period and the way P loads of Brittany rivers have evolved through time. Both mean DP and TP loads have been divided by more than two over the last 20 years. Mean LFDP-load decreased by more than 60% and mean LFTP-load by more than 45% on average over the same period showing that this marked temporal decrease in total load is largely due to the decrease of domestic and industrial P effluents. A global shift in P inputs apportionment to freshwaters thus occurred in Brittany since 20 years as agricultural nonpoint sources now contribute a greater portion of inputs showing the efficiency of the recent control of point sources by enhancement of water treatment plant and removal of phosphates in detergents. The spatialized P loads provided by this study could give a basis for a better understanding of the factors that drives the P transfers in Brittany soils and hotspots of P emissions while the LFP-load indicator can be a tool to assess effects of point-source P mitigation plans.

Factors Controlling Nitrogen Loadings in Major River Basins Across the United States

NASA Astrophysics Data System (ADS)

Boyer, E. W.; Alexander, R. B.; Galloway, J. N.; Golden, H. E.; Moore, R. B.; Schwarz, G. E.; Harvey, J. W.; Gomez-Velez, J. D.; Scott, D.; Clune, J.

2017-12-01

Inputs of reactive nitrogen (all N species except for N2) have been increasing worldwide, largely due to human activities associated with food production and energy consumption via the combustion of fossil fuels and biofuels. Despite the obvious essential benefits of a plentiful supply of food and energy, the adverse consequences associated with the accumulation of N in the environment are large. Most of the N created by human activities is released to the environment, often with unintended negative consequences. The greater the inputs of N to the landscape, the greater the potential for negative effects - caused by greenhouse gas production, ground level ozone, acid deposition, and N overload; which in turn can contribute to climate change, degradation of soils and vegetation, acidification of surface waters, coastal eutrophication, hypoxia, habitat loss, and loss of stratospheric ozone. Here we present a contemporary inventory of reactive N inputs to major water regions in the United States, and discuss accounting methods for quantifying N sources and transport. Furthermore, we quantify loadings of N from terrestrial headwaters downstream to coastal estuaries and embayments. N delivery to downstream waters is influenced by nutrient sources as well as coupled hydrological and biogeochemical processes occurring along the river corridor (e.g., travel time distributions, denitrification, and storage) that scale with stream size and are affected by impoundments such as lakes and reservoirs. This underscores the need to account for the nonlinear interactions of aquatic transport processes with watershed nutrient sources, as well as cumulative effects, in developing efficient nutrient reduction strategies. Our work is useful as a benchmark of the current N situation against which future progress can be assessed in varying water regions of the country; amidst changing N inputs, policies, and management strategies. Our results stem from the EPA Integrated Nitrogen Advisory Committee, the EPA Center for Integrated Multi-Scale Nutrient Pollution Solutions, and the John Wesley Powell Center River Corridor Working Group.

[Analysis on nitrogen and phosphorus loading of non-point sources in Shiqiao river watershed based on L-THIA model].

PubMed

Li, Kai; Zeng, Fan-Tang; Fang, Huai-Yang; Lin, Shu

2013-11-01

Based on the Long-term Hydrological Impact Assessment (L-THIA) model, the effect of land use and rainfall change on nitrogen and phosphorus loading of non-point sources in Shiqiao river watershed was analyzed. The parameters in L-THIA model were revised according to the data recorded in the scene of runoff plots, which were set up in the watershed. The results showed that the distribution of areas with high pollution load was mainly concentrated in agricultural land and urban land. Agricultural land was the biggest contributor to nitrogen and phosphorus load. From 1995 to 2010, the load of major pollutants, namely TN and TP, showed an obviously increasing trend with increase rates of 17.91% and 25.30%, respectively. With the urbanization in the watershed, urban land increased rapidly and its area proportion reached 43.94%. The contribution of urban land to nitrogen and phosphorus load was over 40% in 2010. This was the main reason why pollution load still increased obviously while the agricultural land decreased greatly in the past 15 years. The rainfall occurred in the watershed was mainly concentrated in the flood season, so the nitrogen and phosphorus load of the flood season was far higher than that of the non-flood season and the proportion accounting for the whole year was over 85%. Pearson regression analysis between pollution load and the frequency of different patterns of rainfall demonstrated that rainfall exceeding 20 mm in a day was the main rainfall type causing non-point source pollution.

Relating watershed nutrient loads to satellite derived estuarine water quality

EPA Science Inventory

Nutrient enhanced phytoplankton production is a cause of degraded estuarine water quality. Yet, relationships between watershed nutrient loads and the spatial and temporal scales of phytoplankton blooms and subsequent water quality impairments remain unquantified for most systems...

Impact of simulated atmospheric nitrogen deposition on nutrient cycling and carbon sink via mycorrhizal fungi in two nutrient-poor peatlands

NASA Astrophysics Data System (ADS)

Larmola, Tuula; Kiheri, Heikki; Bubier, Jill L.; van Dijk, Netty; Dise, Nancy; Fritze, Hannu; Hobbie, Erik A.; Juutinen, Sari; Laiho, Raija; Moore, Tim R.; Pennanen, Taina

2017-04-01

Peatlands store one third of the global soil carbon (C) pool. Long-term fertilization experiments in nutrient-poor peatlands showed that simulated atmospheric nitrogen (N) deposition does not enhance ecosystem C uptake but reduces C sink potential. Recent studies have shown that a significant proportion of C input to soil in low-fertility forests entered the soil through mycorrhizal fungi, rather than as plant litter. Is atmospheric N deposition diminishing peatland C sink potential due to the suppression of ericoid mycorrhizal fungi? We studied how nutrient addition influences plant biomass allocation and the extent to which plants rely on mycorrhizal N uptake at two of the longest-running nutrient addition experiments on peatlands, Whim Bog, United Kingdom, and Mer Bleue Bog, Canada. We determined the peak growing season aboveground biomass production and coverage of vascular plants using the point intercept method. We also analyzed isotopic δ15N patterns and nutrient contents in leaves of dominant ericoid mycorrhizal shrubs as well as the non-mycorrhizal sedge Eriophorum vaginatum under different nutrient addition treatments. The treatments receive an additional load of 1.6-6.4 N g m-2 y-1 either as ammonium (NH4) nitrate (NO3) or NH4NO3 and with or without phosphorus (P) and potassium (K), alongside unfertilized controls. After 11-16 years of nutrient addition, the vegetation structure had changed remarkably. Ten of the eleven nutrient addition treatments showed an increase of up to 60% in total vascular plant abundance. Only three (NH4Cl, NH4ClPK, NaNO3PK) of the nutrient addition treatments showed a concurrent decrease of down to 50% in the relative proportion of ericoid mycorrhizal shrubs to total vascular plant abundance. The response to nutrient load may be explained by the water table depth, the form of N added and whether N was added with PK. Shrubs were strong competitors at the dry Mer Bleue bog while sedges gained in abundance at the wetter Whim bog. Our results also suggest that the impacts of reduced and oxidized N on above ground biomass of ericoid shrubs differ and that plants have become increasingly P limited under high simulated atmospheric N deposition. Combined with mycorrhizal abundance and foliar isotopic δ15N patterns, the data will allow us to estimate the extent to which plants rely on mycorrhizal N uptake and whether mycorrhizal responses are linked to diminished C sink potential. This evidence is needed to establish critical loads for C sink potential in peatlands.

Capturing microbial sources distributed in a mixed-use watershed within an integrated environmental modeling workflow

EPA Science Inventory

Many watershed models simulate overland and instream microbial fate and transport, but few provide loading rates on land surfaces and point sources to the waterbody network. This paper describes the underlying equations for microbial loading rates associated with 1) land-applied ...

Capturing microbial sources distributed in a mixed-use watershed within an integrated environmental modeling workflow

USDA-ARS?s Scientific Manuscript database

Many watershed models simulate overland and instream microbial fate and transport, but few provide loading rates on land surfaces and point sources to the waterbody network. This paper describes the underlying equations for microbial loading rates associated with 1) land-applied manure on undevelope...

A Workflow to Model Microbial Loadings in Watersheds ...

EPA Pesticide Factsheets

Many watershed models simulate overland and instream microbial fate and transport, but few actually provide loading rates on land surfaces and point sources to the water body network. This paper describes the underlying general equations for microbial loading rates associated with 1) land-applied manure on undeveloped areas from domestic animals; 2) direct shedding on undeveloped lands by domestic animals and wildlife; 3) urban or engineered areas; and 4) point sources that directly discharge to streams from septic systems and shedding by domestic animals. A microbial source module, which houses these formulations, is linked within a workflow containing eight models and a set of databases that form a loosely configured modeling infrastructure which supports watershed-scale microbial source-to-receptor modeling by focusing on animal-impacted catchments. A hypothetical example application – accessing, retrieving, and using real-world data – demonstrates the ability of the infrastructure to automate many of the manual steps associated with a standard watershed assessment, culminating with calibrated flow and microbial densities at the pour point of a watershed. Presented at 2016 Biennial Conference, International Environmental Modelling & Software Society.

Filling the gap for phosphorus tracing in the eco-hydrological system: are oxygen stable isotopes in phosphate a possible tool?

NASA Astrophysics Data System (ADS)

Stamm, C.; Tamburini, F.; Hahn, C.; Stadelmann, F.; Bernasconi, S. M.; Frossard, E.

2011-12-01

Phosphorus is a limiting nutrient in many ecosystems. However, freshwater systems are experiencing nutrient overload and consequent eutrophication, caused mainly by a poor use of resources and in many situations by the input of a surplus of nutrients from agriculture. The sources of nutrient pollution together with the fate of the nutrients once in the water system need to be identified and understood, so that a better management can be implemented. There are multiple agricultural P-sources like mineral fertilizers, animal excreta, plant residues, soils, and since P has only one stable isotope, no analytical method allows to directly distinguishing P from its different possible source. However, the isotopic signature of oxygen associated to phosphate (δ18O-P) has been considered to be a promising tool for such source tracing in the environment. The main limitation of using this tool as a tracer is that biological activity could erase the original source signature, which is overprinted by a temperature dependent equilibration with oxygen in water. We present data from the region of Lake Baldegg (Central Switzerland), which is characterized by a high animal density (dairy cows, pigs) and intensive grassland cultivation. P losses from the grasslands constitute the main source of P for the freshwater system. Using δ18O-P, we have first characterized animal manure, soil available P, and plant P, the three main possible Pi sources to the system, and we have determined the δ18O-P of three brooks at different time points. Phosphorus concentration, oxygen isotopic composition of water and temperature were also monitored. The three sources of P showed well distinct signatures, with values from animal manures and plants being 12% and higher than 20%, respectively. Depending on the time of sampling, the δ18O-P in the brooks showed deviations from the expected equilibrium, pointing to a contribution of P coming from animal manure. Data from runoff experiments in the same region showed an inverse correlation between δ18O-P in runoff water and P concentration in the soil. This indicated that manure P contributed directly to P mobilized into the surface runoff. The presented results, together with the outcome of other recent studies, indicate the usefulness and potentiality of δ18O-P a tracer for P in hydrological systems.

Spatial and temporal variation of nutrients in groundwater and associated processes in the coastal zone of the Pearl River Delta, China

NASA Astrophysics Data System (ADS)

Chen, J.

2017-12-01

Rapid urbanization has occurred in the Pearl River Delta since 1980s, resulting in tremendous accumulation of population and material in an area of around 1.1x104 km2. Massive nutrients were released to the coastal zone either via the Pearl River or the aquifer, and effects of these nutrients on ecosystem and drinking water supply are a big public concern. Field campaigns to collect groundwater samples were implemented in rainy (April- September) and dry seasons (October - March) during the period of 2005-2016, and samples were analyzed for major ions, nutrients, multiple isotopes, N2O and microbiological DNA. Seasonal and spatial pattern of nutrients from the recharge to the discharge zone in two case study areas were identified and compared regarding relevant N transformation processes. Main sources of nutrients in groundwater and major mechanisms, e.g. denitrification, nitrification and etc., involved in these processes were raised by integrating microbiological, isotopic and geochemical evidences. Driven forces of the change in nutrients in the past 10 years were investigated based on statistical data, and total nutrient load in groundwater in the delta was estimated.

Tile drainage as karst: Conduit flow and diffuse flow in a tile-drained watershed

USGS Publications Warehouse

Schilling, K.E.; Helmers, M.

2008-01-01

The similarity of tiled-drained watersheds to karst drainage basins can be used to improve understanding of watershed-scale nutrient losses from subsurface tile drainage networks. In this study, short-term variations in discharge and chemistry were examined from a tile outlet collecting subsurface tile flow from a 963 ha agricultural watershed. Study objectives were to apply analytical techniques from karst springs to tile discharge to evaluate water sources and estimate the loads of agricultural pollutants discharged from the tile with conduit, intermediate and diffuse flow regimes. A two-member mixing model using nitrate, chloride and specific conductance was used to distinguish rainwater versus groundwater inputs. Results indicated that groundwater comprised 75% of the discharge for a three-day storm period and rainwater was primarily concentrated during the hydrograph peak. A contrasting pattern of solute concentrations and export loads was observed in tile flow. During base flow periods, tile flow consisted of diffuse flow from groundwater sources and contained elevated levels of nitrate, chloride and specific conductance. During storm events, suspended solids and pollutants adhered to soil surfaces (phosphorus, ammonium and organic nitrogen) were concentrated and discharged during the rapid, conduit flow portion of the hydrograph. During a three-day period, conduit flow occurred for 5.6% of the time but accounted for 16.5% of the total flow. Nitrate and chloride were delivered primarily with diffuse flow (more than 70%), whereas 80-94% of total suspended sediment, phosphorus and ammonium were exported with conduit and intermediate flow regimes. Understanding the water sources contributing to tile drainage and the manner by which pollutant discharge occurs from these systems (conduit, intermediate or diffuse flow) may be useful for designing, implementing and evaluating non-point source reduction strategies in tile-drained landscapes. ?? 2007 Elsevier B.V. All rights reserved.

Status of Lake Erie phosphorus loads and concentrations

EPA Science Inventory

Under the Great Lakes Water Quality Protocol of 2012, nutrient loading and nutrient concentrations for open and nearshore waters must be re-evaluated for Substance Objectives that are consistent with overall Ecosystem Objectives. One of the primary driving nutrients of interest ...

Potential urban runoff impacts and contaminant distributions in shoreline and reservoir environments of Lake Havasu, southwestern United States.

PubMed

Wilson, Doyle C

2018-04-15

Heavy metal, nutrient, and hydrocarbon levels in and adjacent to Lake Havasu, a regionally significant water supply reservoir with a highly controlled, dynamic flow regime, are assessed in relation to possible stormwater runoff impacts from an arid urban center. Shallow groundwater and sediment analyses from ephemeral drainage (wash) mouths that convey stormwater runoff from Lake Havasu City, Arizona to the reservoir, provided contaminant control points and correlation ties with the reservoir environment. Fine-grain sediments tend to contain higher heavy metal concentrations whereas nutrients are more evenly distributed, except low total organic carbon levels from young wash mouth surfaces devoid of vegetation. Heavy metal and total phosphate sediment concentrations in transects from wash mouths into the reservoir have mixed and decreasing trends, respectively. Both series may indicate chemical depositional influences from urban runoff, yet no statistically significant concentration differences occur between specific wash mouths and corresponding offshore transects. Heavy metal pollution indices of all sediments indicate no discernible to minor contamination, indicating that runoff impacts are minimal. Nevertheless, several heavy metal concentrations from mid-reservoir sediment sites increase southward through the length of the reservoir. Continual significant water flow through the reservoir may help to disperse locally derived runoff particulates, which could mix and settle down gradient with chemical loads from upriver sources and local atmospheric deposition. Incorporating the shoreline environment with the reservoir investigation provides spatial continuity in assessing contaminant sources and distribution patterns. This is particularly acute in the investigation of energetic, flow-through reservoirs in which sources may be overlooked if solely analyzing the reservoir environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluating the potential for watershed restoration to reduce nutrient loading to Upper Klamath Lake, Oregon

USGS Publications Warehouse

McCormick, Paul V.; Campbell, Sharon G.

2007-01-01

A literature review of best management practices to reduce nutrient loading was performed to provide information for resource managers in the Klamath Basin, Oregon. Although BMPs have already been implemented in the watershed, some sense of their effectiveness in reducing phosphorus loading and their cost for installation and maintenance is still lacking. This report discusses both causes of nutrient loading and a wide-variety of BMPs used to treat or reduce causal factors. We specifically focused on cattle grazing as the principal land-use and causal factor for nutrient loading in the Klamath Basin above Upper Klamath Lake, Oregon. Several BMP types, including stream corridor fencing, riparian buffer strips and constructed wetlands, seem to have potential for reducing phosphorus loading that may result from cattle grazing. However, no single BMP is likely to be the most effective in all locations or situations.

Explanatory characteristics for nutrient concentrations and loads in the Sava River Catchment and cross-regionally

NASA Astrophysics Data System (ADS)

Levi, L.; Cvetkovic, V.; Destouni, G.

2015-12-01

This study compiles estimates of waterborne nutrient concentrations and loads in the Sava River Catchment (SRC). Based on this compilation, we investigate hotspots of nutrient inputs and retention along the river, as well as concentration and load correlations with river discharge and various human drivers of excess nutrient inputs to the SRC. For cross-regional assessment and possible generalization, we also compare corresponding results between the SRC and the Baltic Sea Drainage Basin (BSDB). In the SRC, one small incremental subcatchment, which is located just downstream of Zagreb and has the highest population density among the SRC subcatchments, is identified as a major hotspot for net loading (input minus retention) of both total nitrogen (TN) and total phosphorus (TP) to the river and through it to downstream areas of the SRC. The other SRC subcatchments exhibit relatively similar characteristics with smaller net nutrient loading. The annual loads of both TN and TP along the Sava River exhibit dominant temporal variability with considerably higher correlation with annual river discharge (R2 = 0.51 and 0.28, respectively) than that of annual average nutrient concentrations (R2 = 0.0 versus discharge for both TN and TP). Nutrient concentrations exhibit instead dominant spatial variability with relatively high correlation with population density among the SRC subcatchments (R2=0.43-0.64). These SRC correlation characteristics compare well with corresponding ones for the BSDB, even though the two regions are quite different in their hydroclimatic, agricultural and wastewater treatment conditions. Such cross-regional consistency in dominant variability type and explanatory catchment characteristics may be a useful generalization basis, worthy of further investigation, for at least first-order estimation of nutrient concentration and load conditions in less data-rich regions.

Nutrients in Streams and Rivers Across the Nation -- 1992-2001

USGS Publications Warehouse

Mueller, David K.; Spahr, Norman E.

2006-01-01

Nutrient compounds of nitrogen and phosphorus were investigated in streams and rivers sampled as part of the U.S. Geological Survey National Water-Quality Assessment (NAWQA) Program. Nutrient data were collected in 20 NAWQA study units during 1992-95, 16 study units during 1996-98, and 15 study units during 1999-2001. To facilitate comparisons among sampling sites with variable sampling frequency, daily loads were determined by using regression models that relate constituent transport to streamflow and time. Model results were used to compute mean annual loads, yields, and concentrations of ammonia, nitrate, total nitrogen, orthophosphate, and total phosphorus, which were compared among stream and river sampling sites. Variations in the occurrence and distribution of nutrients in streams and rivers on a broad national scale reflect differences in the sources of nutrient inputs to the upstream watersheds and in watershed characteristics that affect movement of those nutrients. Sites were classified by watershed size and by land use in the upstream watershed: agriculture, urban, and undeveloped (forest or rangeland). Selection of NAWQA urban sites was intended to avoid effects of major wastewater-treatment plants and other point sources, but in some locations this was not feasible. Nutrient concentrations and yields generally increased with anthropogenic development in the watershed. Median concentrations and yields for all constituents at sites downstream from undeveloped areas were less than at sites downstream from agricultural or urban areas. Concentrations of ammonia, orthophosphate, and total phosphorus at agricultural and urban sites were not significantly different; however, concentrations of nitrate and total nitrogen were higher at agricultural than at urban sites. Total nitrogen concentrations at agricultural sites were higher in areas of high nitrogen input or enhanced transport, such as irrigation or artificial drainage that can rapidly move water from cropland to streams (Midwest, Northern Plains, and western areas of the United States). Concentrations were lower in the Southeast, where more denitrification occurs during transport of nitrogen compounds in shallow ground water. At urban sites, high concentrations of ammonia and orthophosphate were more prevalent downstream from wastewater-treatment plants. At sites with large watersheds and high mean-annual streamflow ('large-watershed' sites), concentrations of most nutrients were significantly less than at sites downstream from agricultural or urban areas. Total nitrogen concentrations at large-watershed sites were higher in Midwest agricultural areas and lower in the Western United States, where agricultural and urban development is less extensive. Total phosphorus concentrations at large-watershed sites were higher in areas of greater potential erosion and low overall runoff such as the arid areas in the West. Although not as distinct as seasonal patterns of streamflow, geographic patterns of seasonally high and low concentrations of total nitrogen and total phosphorus were identified in the data. Seasonal patterns in concentrations of total nitrogen generally mirror seasonal patterns in streamflow in the humid Eastern United States but are inverse to seasonal patterns in streamflow in the semiarid interior West. Total phosphorus concentrations typically have the opposite regional relation with streamflow; high concentrations coincide with high streamflows in the interior West. In the NAWQA Program, sites downstream from relatively undeveloped areas were selected to provide a baseline for comparison to sites with potential effects of urban development and agriculture. Concentrations of nitrate, total nitrogen, and total phosphorus at NAWQA undeveloped sites were found to be greater than values reported by other studies for conditions of essentially no development (background conditions). Concentrations at NAWQA undeveloped sites represent conditions

Inter-event variability in urban stormwater runoff response associated with hydrologic connectivity

NASA Astrophysics Data System (ADS)

Hondula, K. L.

2015-12-01

Urbanization alters the magnitude and composition of hydrologic and biogeochemical fluxes from watersheds, with subsequent deleterious consequences for receiving waters. Projected changes in storm characteristics such as rainfall intensity and event size are predicted to amplify these impacts and render current regulations inadequate for protecting surface water quality. As stormwater management practices (BMPs) are increasingly being relied upon to reduce excess nutrient pollution in runoff from residential development, empirical investigation of their performance across a range of conditions is warranted. Despite substantial investment in urban and suburban BMPs, significant knowledge gaps exist in understanding how landscape structure and precipitation event characteristics influence the amount of stormwater runoff and associated nutrient loads from these complex catchments. Increasing infiltration of stormwater before it enters the sewer network (source control) is hypothesized to better mimic natural hydrologic and biogeochemical fluxes compared to more centralized BMPs at sewer outlets such as wet and dry ponds. Rainfall and runoff quality and quantity were monitored in four small (1-5 ha) residential catchments in Maryland to test the efficacy of infiltration-based stormwater management practices in comparison to end-of-pipe BMPs. Results indicated that reduced hydrologic connectivity associated with infiltration-based practices affected the relationship between the magnitude of rainfall events and water yield , but only for small precipitation events: compared to end-of-pipe BMPs, source control was associated with both lower runoff ratios and lower nutrient export per area for a given rainfall event size. We found variability in stormwater runoff responses (water yield, quality, and nutrient loads) was associated with precipitation event size, antecedent rainfall, and hydrologic connectivity as quantified by a modified directional connectivity index. Accounting for the interactive effects of landscape structure and precipitation event characteristics can reduce the uncertainty surrounding stormwater runoff responses in complex urban watersheds.

A Workflow to Model Microbial Loadings in Watersheds

EPA Science Inventory

Many watershed models simulate overland and instream microbial fate and transport, but few actually provide loading rates on land surfaces and point sources to the water body network. This paper describes the underlying general equations for microbial loading rates associated wit...

Benthic nitrogen turnover processes in coastal sediments at the Danube Delta

NASA Astrophysics Data System (ADS)

Bratek, Alexander; Dähnke, Kirstin; Neumann, Andreas; Möbius, Jürgen; Graff, Florian

2017-04-01

The Black Sea Shelf has been exposed to strong anthropogenic pressures from intense fisheries and high nutrient inputs and eutrophication over the past decades. In the light of decreasing riverine nutrient loads and improving nutrient status in the water column, nutrient regeneration in sediments and biological N-turnover in the Danube Delta Front have an important effect on nutrient loads in the shelf region. In May 2016 we determined pore water nutrient profiles in the Danube River Delta-Black Sea transition zone, aiming to assess N-regeneration and elimination based on nutrient profiles and stable N- isotope changes (nitrate and ammonium) in surface water masses and in pore water. We aimed to investigate the magnitude and isotope values of sedimentary NH4+ and NO3- and their impact on the current N-budget in Black Sea Shelf water. Based on changes in the stable isotope ratios of NO3- and NH4+, we aimed to differentiate diffusion and active processing of ammonium as well as nitrate sources and sinks in bottom water. First results show that the concentration of NH4+ in pore water increases with depth, reaching up to 1500 µM in deeper sediment layers. We find indications for high fluxes of ammonium to the overlying water, while stable isotope profiles of ammonium suggest that further processing, apart from mere diffusion, acts on the pore water ammonium pool. Nitrate concentration and stable isotope profiles show rapid consumption in deeper anoxic sediment layers, but also suggest that nitrate regeneration in bottom water increases the dissolved nitrate pool. Overall, the isotope and concentration data of pore water ammonium clearly mirror a combination of turnover processes and diffusion.

Analysis of long-term water quality for effective river health monitoring in peri-urban landscapes--a case study of the Hawkesbury-Nepean river system in NSW, Australia.

PubMed

Pinto, U; Maheshwari, B L; Ollerton, R L

2013-06-01

The Hawkesbury-Nepean River (HNR) system in South-Eastern Australia is the main source of water supply for the Sydney Metropolitan area and is one of the more complex river systems due to the influence of urbanisation and other activities in the peri-urban landscape through which it flows. The long-term monitoring of river water quality is likely to suffer from data gaps due to funding cuts, changes in priority and related reasons. Nevertheless, we need to assess river health based on the available information. In this study, we demonstrated how the Factor Analysis (FA), Hierarchical Agglomerative Cluster Analysis (HACA) and Trend Analysis (TA) can be applied to evaluate long-term historic data sets. Six water quality parameters, viz., temperature, chlorophyll-a, dissolved oxygen, oxides of nitrogen, suspended solids and reactive silicates, measured at weekly intervals between 1985 and 2008 at 12 monitoring stations located along the 300 km length of the HNR system were evaluated to understand the human and natural influences on the river system in a peri-urban landscape. The application of FA extracted three latent factors which explained more than 70 % of the total variance of the data and related to the 'bio-geographical', 'natural' and 'nutrient pollutant' dimensions of the HNR system. The bio-geographical and nutrient pollution factors more likely related to the direct influence of changes and activities of peri-urban natures and accounted for approximately 50 % of variability in water quality. The application of HACA indicated two major clusters representing clean and polluted zones of the river. On the spatial scale, one cluster was represented by the upper and lower sections of the river (clean zone) and accounted for approximately 158 km of the river. The other cluster was represented by the middle section (polluted zone) with a length of approximately 98 km. Trend Analysis indicated how the point sources influence river water quality on spatio-temporal scales, taking into account the various effects of nutrient and other pollutant loads from sewerage effluents, agriculture and other point and non-point sources along the river and major tributaries of the HNR. Over the past 26 years, water temperature has significantly increased while suspended solids have significantly decreased (p < 0.05). The analysis of water quality data through FA, HACA and TA helped to characterise the key sections and cluster the key water quality variables of the HNR system. The insights gained from this study have the potential to improve the effectiveness of river health-monitoring programs in terms of cost, time and effort, particularly in a peri-urban context.

Loads of nitrate, phosphorus, and total suspended solids from Indiana watersheds

USGS Publications Warehouse

Bunch, Aubrey R.

2016-01-01

Transport of excess nutrients and total suspended solids (TSS) such as sediment by freshwater systems has led to degradation of aquatic ecosystems around the world. Nutrient and TSS loads from Midwestern states to the Mississippi River are a major contributor to the Gulf of Mexico Hypoxic Zone, an area of very low dissolved oxygen concentration in the Gulf of Mexico. To better understand Indiana’s contribution of nutrients and TSS to the Mississippi River, annual loads of nitrate plus nitrite as nitrogen, total phosphorus, and TSS were calculated for nine selected watersheds in Indiana using the load estimation model, S-LOADEST. Discrete water-quality samples collected monthly by the Indiana Department of Environmental Management’s Fixed Stations Monitoring Program from 2000–2010 and concurrent discharge data from the U. S. Geological Survey streamflow gages were used to create load models. Annual nutrient and TSS loads varied across Indiana by watershed and hydrologic condition. Understanding the loads from large river sites in Indiana is important for assessing contributions of nutrients and TSS to the Mississippi River Basin and in determining the effectiveness of best management practices in the state. Additionally, evaluation of loads from smaller upstream watersheds is important to characterize improvements at the local level and to identify priorities for reduction.

A hindcast and forecast of management of agricultural nutrient losses in Denmark: a change in paradigm (Invited)

NASA Astrophysics Data System (ADS)

kronvang, B.; Blicher-Mathiesen, G.; Windolf, J.; Grant, R.

2013-12-01

Four major Action Plans on the Aquatic Environment have been implemented in Denmark since 1987 with the aim to reduce by 50% the nitrogen (N) loading and by 80% the phosphorus (P) loading to the aquatic environment. At the same time the Danish National Aquatic Monitoring and Assessment Programme (NOVA) was launched with the aim to follow the effects of the obligatory implemented management strategies in Danish agriculture. Monitoring of the effects took place in 5 small agricultural catchments in soil water, groundwater and surface waters with annual interviews of farmers practices at field level as well as a general monitoring of nutrient concentrations in groundwater, streams, rivers, lakes and estuaries all over Denmark. Considerable changes in agricultural practice (storage of slurry, ban on slurry spreading in autumn and winter, strict requirements to N-use in animal manure, N-norms to all crops to be fixed to 10% below economic optimum, etc.) have resulted in a reduction of the net N-surplus from 136 to 75 kg N ha-1 yr-1 (45%) and the net P-surplus from 19 to around 0 kg P ha-1 yr-1 (100%) during the period 1985-2011..Twenty-five years of experience gathered from NOVA have shown that the losses of total N (TN) and total P (TP) to the marine environment from both point sources and diffuse sources has decreased with 50% and 50%, respectively. The reduction in TN losses alone amounts to 40%, whereas no general reduction in TP from diffuse losses can be detected. Despite the great efforts in improving the management of N and P in Danish agriculture the sector is today still the major source of both N (80%) and P (50%) in Danish streams, lakes and coastal waters. The ecological conditions in Danish streams, lakes and estuaries are still below the at least good ecological quality required by the EU Water Framework Directive adopted in year 2000. As global demand for food is increasing the Danish Government last year initiated a commission to publish a white book on ';Nature and Agriculture'. The commission has just published their recommendations for the future regulation and management of the Danish agricultural production as the aquatic environment still needs to be improved, and concurrently, the airborne nutrient load on nature must be reduced, and agriculture must help reduce the overall climate change impact. The Commission suggests that the current environmental regulation of agriculture with general fertilizer norms and limits on production cannot alone deal with the challenges, because the costs will be too high for the farmers. They, conclude that it is necessary to explore new territory and make regulation more targeted. Trends in the use of chemical fertilizers in Danish agriculture 1950-2012 and the responses following adopted Action Plans (APAE= Action Plan Aquatic Environment).

TMDLS: AFTER POINT SOURCES, WHAT CAN WE DO NEXT?

EPA Science Inventory

Section 303(d) of the Clean Water Act required TMDLs (total maximum daily loads) for all waters for which effluent or point source limitations are insufficient to meet water quality standards. Concerns may arise regarding the manner by which TMDLs are established, the corrective ...

Transport, sloughing and settling rates of estuarine macrophytes: Mechanisms and ecological implications

NASA Astrophysics Data System (ADS)

Flindt, M. R.; Pedersen, C. B.; Amos, C. L.; Levy, A.; Bergamasco, A.; Friend, P. L.

2007-05-01

The study of plant-bound nutrient transport has been largely neglected in estuaries. Lately however, it has been shown that nutrients bound to macroalgae and seagrasses can constitute a major part of the nutrient transport in shallow tidal estuaries. Organic detritus in estuaries comes from various sources. This paper looks into the source of detritus from sloughing, and the transport behaviour of plant detritus under unidirectional flows. In order to determine the extent of the sloughing of macrophytes, the threshold current velocities for the traction and resuspension of the most common submersed macrophytes in Venice Lagoon ( Ulva lactuca, Enteromorpha sp., Ceramium rubrum, Cladophora sp., and Chaetomorpha linum) were studied in a laboratory flume. It was found that all macrophytes subjected to flows of 1.5-3.0 cm s -1 move initially as bed load. The threshold for suspension of the macrophyte tissue was at current speeds >3 cm s -1. The exception was the filamentous macroalgae, C. linum, which moved as bed load at all current speeds. This implies that the advection of plant-bound nutrients in Venice Lagoon is widespread and takes place over virtually all stages of the tide. Initial experiments were carried out on unattached macroalgae. A second study focused on the sloughing of attached macroalgae by steady currents. The threshold current speeds at which sloughing commenced varied between different types of algae, and sloughing rate was related largely to current speed. The resuspension rates were uniform between the different macrophyte groups. Our results help explain why plant matter has been trapped in nets close to the bed of Venice Lagoon on ebbing tides. It shows that a major component of the bedload is organic in origin. The results verify that a large proportion of the net nutrient export from estuaries is bound in macrophyte tissue. These findings need to be included in future ecological models that describe the resuspension, sloughing and settling of macrophytes.

Influence of submarine springs and wastewater on nutrient dynamics of Caribbean seagrass meadows

NASA Astrophysics Data System (ADS)

Carruthers, T. J. B.; van Tussenbroek, B. I.; Dennison, W. C.

2005-08-01

The east coast of the Yucatan Peninsula, Mexico, consists of highly permeable limestone, such that surface flow and rivers are absent in this region. Extensive underground cave systems connect sink holes (cenotes) to submarine springs (ojos de aqua), which vent into the seagrass meadows of the adjacent oligotrophic coastal lagoons. This study investigated the potential for these submarine springs to influence nutrient processes within seagrass meadows, by assessing nutrient status of Thalassia testudinum meadows in two contrasting coastal lagoons along the north eastern Yucatan peninsula. Tissue nutrient concentrations as well as δ 15N values of T. testudinum were surveyed in the Puerto Morelos Reef Lagoon and the Nichupte Lagoon System, Cancun Hotel Zone, during an extended dry period and again following heavy rainfall. After a period of heavy rainfall, T. testudinum near submarine springs in Puerto Morelos Reef Lagoon had exceptionally high leaf tissue phosphorus concentrations of 0.38±0.06%. These submarine springs may have been a direct source of phosphorus and/or a source of iron to this very iron limited carbonate system. Thalassia testudinum nutrient concentrations suggest that nitrogen loading to the Nichupte Lagoon System is regionally high and has increased over the past decade (mean leaf N: 2.04% N in 1991 to 2.71% N in 2002). Nitrogen content in leaf tissue of T. testudinum was significantly higher within the poorly flushed Nichupte Lagoon System (2.93±0.12% N) than in the well-flushed Puerto Morelos Reef Lagoon (1.80±0.07% N). Stable isotope ratios of nitrogen suggest that this high and increasing nitrogen loading within the Nichupte Lagoon System is a result of wastewater nitrogen (δ 15N 9.06±0.07 in northern Nichupte Lagoon System vs. 1.69±0.07 in Puerto Morelos Reef Lagoon).

Quantifying ocean and ice sheet contributions to nutrient fluxes in Sermilik Fjord, Southeast Greenland

NASA Astrophysics Data System (ADS)

Cape, M. R.; Straneo, F.; Beaird, N.; Bundy, R.; Charette, M. A.

2016-12-01

Meltwater discharged at the margins of the Greenland Ice Sheet (GrIS) represents a potential source of nutrients to biological communities downstream. In Greenland's glacial fjords, this discharge occurs at depth below and along the face of deeply grounded marine-terminating glaciers. This process drives vigorous circulation and mixing between melt and ambient waters at the ice-ocean margins, giving rise to a new glacially modified water mass (GMW) which constitutes the primary vehicle for transport of meltwater in the marine environment. While previous field studies have noted nutrient enrichment in GMW with respect to unmodified waters along the shelf, the source of this enrichment, whether due to entrainment of deep ambient waters or input by meltwater, remains poorly understood. This knowledge is however critical in order to evaluate the current and future contributions of the GrIS to marine biogeochemical cycling. Here we shed light on the distribution, composition, and properties of GMW along the GrIS margin by analyzing integrated physical and chemical measurements collected in August 2015 in Sermilik Fjord, a major glacial freshwater export pathway. Our results document up to a doubling of nutrient concentrations (nitrate, silicate, phosphate, and iron) in GMW, which is distributed in the top 300 m of the water column throughout the fjord. Partitioning of ocean and ice sheet contributions to GMW nutrient load demonstrates that upwelled waters are the primary source of macro-nutrients to GMW. We expand on these results to discuss the magnitude of fluxes in context of previous observations along the GrIS margins, export pathways of GMW to the shelf, and knowledge gaps needed to be addressed to better constrain ice sheet contributions to marine ecosystem processes.

Nutrient bioassimilation capacity of aquacultured oysters: quantification of an ecosystem service.

PubMed

Higgins, Colleen B; Stephenson, Kurt; Brown, Bonnie L

2011-01-01

Like many coastal zones and estuaries, the Chesapeake Bay has been severely degraded by cultural eutrophication. Rising implementation costs and difficulty achieving nutrient reduction goals associated with point and nonpoint sources suggests that approaches supplemental to source reductions may prove useful in the future. Enhanced oyster aquaculture has been suggested as one potential policy initiative to help rid the Bay waters of excess nutrients via harvest of bioassimilated nutrients. To assess this potential, total nitrogen (TN), total phosphorous (TP), and total carbon (TC) content were measured in oyster tissue and shell at two floating-raft cultivation sites in the Chesapeake Bay. Models were developed based on the common market measurement of total length (TL) for aquacultured oysters, which was strongly correlated to the TN (R2 = 0.76), TP (R2 = 0.78), and TC (R2 = 0.76) content per oyster tissue and shell. These models provide resource managers with a tool to quantify net nutrient removal. Based on model estimates, 10(6) harvest-sized oysters (76 mm TL) remove 132 kg TN, 19 kg TP, and 3823 kg TC. In terms of nutrients removed per unit area, oyster harvest is an effective means of nutrient removal compared with other nonpoint source reduction strategies. At a density of 286 oysters m(-2), assuming no mortality, harvest size nutrient removal rates can be as high as 378 kg TN ha(-1), 54 kg TP ha(-1), and 10,934 kg TC ha(-1) for 76-mm oysters. Removing 1 t N from the Bay would require harvesting 7.7 million 76-mm TL cultivated oysters.

Predicting nutrient and sediment loadings to streams from landscape metrics: A multiple watershed study from the United States Mid-Atlantic Region

Treesearch

K. Bruce Jones; Anne C. Neale; Malisha S. Nash; Rick D. van Remortel; James D. Wickham; Kurt H. Riitters; Robert V. O' Neill

2001-01-01

There has been an increasing interest in evaluating the relative condition or health of water resources at regional and national scales. Of particular interest is an ability to identify those areas where surface and ground waters have the greatest potential for high levels of nutrient and sediment loadings. High levels of nutrient and sediment loadings can have adverse...

Sources and transport of phosphorus to rivers in California and adjacent states, U.S., as determined by SPARROW modeling

USGS Publications Warehouse

Domagalski, Joseph L.; Saleh, Dina

2015-01-01

The SPARROW (SPAtially Referenced Regression on Watershed attributes) model was used to simulate annual phosphorus loads and concentrations in unmonitored stream reaches in California, U.S., and portions of Nevada and Oregon. The model was calibrated using de-trended streamflow and phosphorus concentration data at 80 locations. The model explained 91% of the variability in loads and 51% of the variability in yields for a base year of 2002. Point sources, geological background, and cultivated land were significant sources. Variables used to explain delivery of phosphorus from land to water were precipitation and soil clay content. Aquatic loss of phosphorus was significant in streams of all sizes, with the greatest decay predicted in small- and intermediate-sized streams. Geological sources, including volcanic rocks and shales, were the principal control on concentrations and loads in many regions. Some localized formations such as the Monterey shale of southern California are important sources of phosphorus and may contribute to elevated stream concentrations. Many of the larger point source facilities were located in downstream areas, near the ocean, and do not affect inland streams except for a few locations. Large areas of cultivated land result in phosphorus load increases, but do not necessarily increase the loads above those of geological background in some cases because of local hydrology, which limits the potential of phosphorus transport from land to streams.

Evaluation of the AnnAGNPS Model for Predicting Runoff and Nutrient Export in a Typical Small Watershed in the Hilly Region of Taihu Lake

PubMed Central

Luo, Chuan; Li, Zhaofu; Li, Hengpeng; Chen, Xiaomin

2015-01-01

The application of hydrological and water quality models is an efficient approach to better understand the processes of environmental deterioration. This study evaluated the ability of the Annualized Agricultural Non-Point Source (AnnAGNPS) model to predict runoff, total nitrogen (TN) and total phosphorus (TP) loading in a typical small watershed of a hilly region near Taihu Lake, China. Runoff was calibrated and validated at both an annual and monthly scale, and parameter sensitivity analysis was performed for TN and TP before the two water quality components were calibrated. The results showed that the model satisfactorily simulated runoff at annual and monthly scales, both during calibration and validation processes. Additionally, results of parameter sensitivity analysis showed that the parameters Fertilizer rate, Fertilizer organic, Canopy cover and Fertilizer inorganic were more sensitive to TN output. In terms of TP, the parameters Residue mass ratio, Fertilizer rate, Fertilizer inorganic and Canopy cover were the most sensitive. Based on these sensitive parameters, calibration was performed. TN loading produced satisfactory results for both the calibration and validation processes, whereas the performance of TP loading was slightly poor. The simulation results showed that AnnAGNPS has the potential to be used as a valuable tool for the planning and management of watersheds. PMID:26364642

Nutrient loads exported from managed catchments reveal emergent biogeochemical stationarity

NASA Astrophysics Data System (ADS)

Basu, Nandita B.; Destouni, Georgia; Jawitz, James W.; Thompson, Sally E.; Loukinova, Natalia V.; Darracq, Amélie; Zanardo, Stefano; Yaeger, Mary; Sivapalan, Murugesu; Rinaldo, Andrea; Rao, P. Suresh C.

2010-12-01

Complexity of heterogeneous catchments poses challenges in predicting biogeochemical responses to human alterations and stochastic hydro-climatic drivers. Human interferences and climate change may have contributed to the demise of hydrologic stationarity, but our synthesis of a large body of observational data suggests that anthropogenic impacts have also resulted in the emergence of effective biogeochemical stationarity in managed catchments. Long-term monitoring data from the Mississippi-Atchafalaya River Basin (MARB) and the Baltic Sea Drainage Basin (BSDB) reveal that inter-annual variations in loads (LT) for total-N (TN) and total-P (TP), exported from a catchment are dominantly controlled by discharge (QT) leading inevitably to temporal invariance of the annual, flow-weighted concentration, $\\overline{Cf = (LT/QT). Emergence of this consistent pattern across diverse managed catchments is attributed to the anthropogenic legacy of accumulated nutrient sources generating memory, similar to ubiquitously present sources for geogenic constituents that also exhibit a linear LT-QT relationship. These responses are characteristic of transport-limited systems. In contrast, in the absence of legacy sources in less-managed catchments, $\\overline{Cf values were highly variable and supply limited. We offer a theoretical explanation for the observed patterns at the event scale, and extend it to consider the stochastic nature of rainfall/flow patterns at annual scales. Our analysis suggests that: (1) expected inter-annual variations in LT can be robustly predicted given discharge variations arising from hydro-climatic or anthropogenic forcing, and (2) water-quality problems in receiving inland and coastal waters would persist until the accumulated storages of nutrients have been substantially depleted. The finding has notable implications on catchment management to mitigate adverse water-quality impacts, and on acceleration of global biogeochemical cycles.

EUTROPHICATION OF COASTAL WATER BODIES: RELATIONSHIPS BETWEEN NUTRIENT LOADING AND ECOLOGICAL RESPONSE

EPA Science Inventory

This newly initiated research will provide environmental managers with an empirical method to develop regional nutrient input limits for East Coast estuaries/coastal water bodies. The goal will be to reduce the current uncertainty associated with nutrient load-response relationsh...

Estimation of real-time N load in surface water using dynamic data driven application system

Treesearch

Y. Ouyang; S.M. Luo; L.H. Cui; Q. Wang; J.E. Zhang

2011-01-01

Agricultural, industrial, and urban activities are the major sources for eutrophication of surface water ecosystems. Currently, determination of nutrients in surface water is primarily accomplished by manually collecting samples for laboratory analysis, which requires at least 24 h. In other words, little to no effort has been devoted to monitoring real-time variations...

A COMPREHENISVE NONPOINT SOURCE FIELD STUDY FOR SEDIMENT, NUTRIENTS AND PATHOGENS IN THE SOUTH FORK BROAD RIVER WATERSHED IN NORTHEAST GEORGIA

EPA Science Inventory

There is an urgent need for EPA to develop protocols for establishing Total Maximum Daily Loads (TMDLs) in streams, lakes and estuaries. A cooperative TMDL field data collection project between ORD and Region 4 is ongoing in the South Fork Broad River Watershed (SFBR), a 245.18 ...

Quantifying the Urban and Rural Nutrient Fluxes to Lake Erie Using a Paired Watershed Approach

NASA Astrophysics Data System (ADS)

Hopkins, M.; Beck, M.; Rossi, E.; Luh, N.; Allen-King, R. M.; Lowry, C.

2016-12-01

Excess nutrients have a detrimental impact on the water quality of Lake Erie, specifically nitrate and phosphate, which can lead to toxic algae blooms. Algae blooms have negatively impacted Lake Erie, which is the main source of drinking water for many coastal Great Lake communities. In 2014 the city of Toledo, Ohio was forced to shut down its water treatment plant due to these toxic algae blooms. The objective of this research is to quantify surface water nutrient fluxes to the eastern basin of Lake Erie using a paired watershed approach. Three different western New York watersheds that feed Lake Erie were chosen based on land use and areal extent: one small urban, one small rural, and one large rural. These paired watersheds were chosen to represent a range of sources of potential nutrient loading to the lake. Biweekly water samples were taken from the streams during the 2015-2016 winter to summer seasonal transition to quantify springtime snow melt effects on nutrient fluxes. These results were compared to the previous year samples, collected over the summer of 2015, which represented wetter conditions. Phosphorous levels were assessed using the ascorbic acid colorimetric assay, while nitrate was analyzed by anion-exchange chromatography. Stream gaging was used to obtain flow measurements and establish a rating curve, which was incorporated to quantify seasonal nutrient fluxes entering the lake. Patterns in the nutrient levels show higher level of nutrients in the rural watersheds with a decrease in concentration over the winter to spring transition. However, nutrient patterns in the urban stream show relatively constant patters of nutrient flux, which is independent of seasonal transition or stream discharge. A comparison of wet and dry seasons shows higher nutrient concentrations during summers with greater rainfall. By identifying the largest contributors of each nutrient, we can better allocate limited attenuation resources.

Effects of Storm Events on Bacteria and Nutrients in the Bayou Chico Watershed

NASA Astrophysics Data System (ADS)

Hobbs, S. E.; Truong, S.

2017-12-01

Levels of Escherichia coli and abiotic nutrients often increase in response to storm events due to urban runoff. The urban setting, aging septic systems, and ample pet waste (predominant sources of bacterial and nutrient contamination) that surround Bayou Chico, provide abundant possibilities for contamination. E. coli is a gram-negative, rod shaped bacteria commonly found in the intestines of animals; while some strains are harmless, others produce dangerous toxins that can cause side effects and sometimes death. Along with E. coli, inorganic nutrient concentrations (orthophosphate, nitrate/nitrite, and ammonium) are key indicators of water quality. Dissolved nutrients promote the growth of primary producers and excessive amounts lead to algal blooms, often reducing biodiversity. Four sites were sampled weekly in June and July 2017; during which, June had the highest rainfall in comparison to the past three years; these four sites represented three different sub-watersheds of the Bayou Chico Watershed, with differing land-use at each site. Historical nutrient and bacterial data from the Bream Fishermen Association was also compared and examined to determine long term trends and obtain a more in-depth understanding of the dynamics of water quality in th urban setting. E. coli levels were universally high (ranging from 98 to 12,997 MPN/100mL) for all sites and did not show observable correlations to rainfall; possibly influenced by the systemic and anomalous heavy precipitation during most of the summer study period. Nitrate was detected at levels between 2.5 and 154.0 µM, while ammonium levels ranged from 0 to 16.1 µM. Three of four stations showed extremely elevated dissolved inorganic nitrogen and ammonium while one station showed low levels of these nutrients. Correlations between these nutrient loads and rainfall, support the hypothesis that runoff into tributary creeks contributes significant inorganic nutrient loads to the Bayou Chico urban estuary.

A Workflow to Model Microbial Loadings in Watersheds (proceedings)

EPA Science Inventory

Many watershed models simulate overland and instream microbial fate and transport, but few actually provide loading rates on land surfaces and point sources to the water body network. This paper describes the underlying general equations for microbial loading rates associated wit...

Twenty years of water-quality studies in the Cheney Reservoir Watershed, Kansas, 1996-2016

USGS Publications Warehouse

Graham, Jennifer L.; Foster, Guy M.; Kramer, Ariele R.

2017-03-31

Since 1996, the U.S. Geological Survey (USGS), in cooperation with the City of Wichita, has done studies in the Cheney Reservoir watershed to understand environmental effects on water-quality conditions. Early studies (1996–2001) determined subwatershed sources of contaminants, nutrient and sediment loading to Cheney Reservoir, changes in reservoir sediment quality over time, and watershed sources of phosphorus. Later studies (2001–present) focused on nutrient and sediment concentrations and mass transport from the watershed; the presence of cyanobacteria, cyanotoxins, and taste-and-odor compounds in the reservoir; and development of regression models for real-time computations of water-quality constituents of interest that may affect drinking-water treatment. This fact sheet summarizes key results from studies done by the USGS during 1996–2016 in the Cheney Reservoir watershed and Cheney Reservoir.

Relative Importance of Different Water Categories as Sources of N-Nitrosamine Precursors.

PubMed

Zeng, Teng; Glover, Caitlin M; Marti, Erica J; Woods-Chabane, Gwen C; Karanfil, Tanju; Mitch, William A; Dickenson, Eric R V

2016-12-20

A comparison of loadings of N-nitrosamines and their precursors from different source water categories is needed to design effective source water blending strategies. Previous research using Formation Potential (FP) chloramination protocols (high dose and prolonged contact times) raised concerns about precursor loadings from various source water categories, but differences in the protocols employed rendered comparisons difficult. In this study, we applied Uniform Formation Condition (UFC) chloramination and ozonation protocols mimicking typical disinfection practice to compare loadings of ambient specific and total N-nitrosamines as well as chloramine-reactive and ozone-reactive precursors in 47 samples, including 6 pristine headwaters, 16 eutrophic waters, 4 agricultural runoff samples, 9 stormwater runoff samples, and 12 municipal wastewater effluents. N-Nitrosodimethylamine (NDMA) formation from UFC and FP chloramination protocols did not correlate, with NDMA FP often being significant in samples where no NDMA formed under UFC conditions. N-Nitrosamines and their precursors were negligible in pristine headwaters. Conventional, and to a lesser degree, nutrient removal wastewater effluents were the dominant source of NDMA and its chloramine- and ozone-reactive precursors. While wastewater effluents were dominant sources of TONO and their precursors, algal blooms, and to a lesser degree agricultural or stormwater runoff, could be important where they affect a major fraction of the water supply.

Simulation of in-stream water quality on global scale under changing climate and anthropogenic conditions

NASA Astrophysics Data System (ADS)

Voss, Anja; Bärlund, Ilona; Punzet, Manuel; Williams, Richard; Teichert, Ellen; Malve, Olli; Voß, Frank

2010-05-01

Although catchment scale modelling of water and solute transport and transformations is a widely used technique to study pollution pathways and effects of natural changes, policies and mitigation measures there are only a few examples of global water quality modelling. This work will provide a description of the new continental-scale model of water quality WorldQual and the analysis of model simulations under changed climate and anthropogenic conditions with respect to changes in diffuse and point loading as well as surface water quality. BOD is used as an indicator of the level of organic pollution and its oxygen-depleting potential, and for the overall health of aquatic ecosystems. The first application of this new water quality model is to river systems of Europe. The model itself is being developed as part of the EU-funded SCENES Project which has the principal goal of developing new scenarios of the future of freshwater resources in Europe. The aim of the model is to determine chemical fluxes in different pathways combining analysis of water quantity with water quality. Simple equations, consistent with the availability of data on the continental scale, are used to simulate the response of in-stream BOD concentrations to diffuse and anthropogenic point loadings as well as flow dilution. Point sources are divided into manufacturing, domestic and urban loadings, whereas diffuse loadings come from scattered settlements, agricultural input (for instance livestock farming), and also from natural background sources. The model is tested against measured longitudinal gradients and time series data at specific river locations with different loading characteristics like the Thames that is driven by domestic loading and Ebro with relative high share of diffuse loading. With scenario studies the influence of climate and anthropogenic changes on European water resources shall be investigated with the following questions: 1. What percentage of river systems will have degraded water quality due to different driving forces? 2. How will climate change and changes in wastewater discharges affect water quality? For the analysis these scenario aspects are included: 1. climate with changed runoff (affecting diffuse pollution and loading from sealed areas), river discharge (causing dilution or concentration of point source pollution) and water temperature (affecting BOD degradation). 2. Point sources with changed population (affecting domestic pollution), connectivity to treatment plants (influencing domestic and manufacturing pollution as well as input from sealed areas and scattered settlements).

Time-scale Dependence of Response of an Estuarine Water Quality Model to Nutrient Loading

EPA Science Inventory

We describe calibration and evaluation of a water quality model being implemented for Narragansett Bay to quantify the response of concentrations of nutrients, phytoplankton chlorophyll a and dissolved oxygen in the Bay to loading rates of nutrients and other boundary conditions....

EFFECTS OF NUTRIENT LOADING ON BIOGEOCHEMICAL AND MICROBIAL PROCESSES IN A NEW ENGLAND SALT MARSH

EPA Science Inventory

Coastal marshes represent an important transitional zone between uplands and estuaries. One important function of marshes is to assimilate nutrient inputs from uplands, thus providing a buffer for anthropogenic nutrient loads. We examined the effects of nitrogen (N) and phosphoru...

Studies on the Effects of High Renewable Penetrations on Driving Point Impedance and Voltage Regulator Performance: National Renewable Energy Laboratory/Sacramento Municipal Utility District Load Tap Changer Driving Point Impedance Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nagarajan, Adarsh; Coddington, Michael H.; Brown, David

Voltage regulators perform as desired when regulating from the source to the load and when regulating from a strong source (utility) to a weak source (distributed generation). (See the glossary for definitions of a strong source and weak source.) Even when the control is provisioned for reverse operation, it has been observed that tap-changing voltage regulators do not perform as desired in reverse when attempting regulation from the weak source to the strong source. The region of performance that is not as well understood is the regulation between sources that are approaching equal strength. As part of this study, wemore » explored all three scenarios: regulator control from a strong source to a weak source (classic case), control from a weak source to a strong source (during reverse power flow), and control between equivalent sources.« less

Exponential Nutrient Loading as a Means to Optimize Bareroot Nursery Fertility of Oak Species

Treesearch

Zonda K. D. Birge; Douglass F. Jacobs; Francis K. Salifu

2006-01-01

Conventional fertilization in nursery culture of hardwoods may involve supply of equal fertilizer doses at regularly spaced intervals during the growing season, which may create a surplus of available nutrients in the beginning and a deficiency in nutrient availability by the end of the growing season. A method of fertilization termed “exponential nutrient loading” has...

ImagingSIMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

2017-11-06

ImagingSIMS is an open source application for loading, processing, manipulating and visualizing secondary ion mass spectrometry (SIMS) data. At PNNL, a separate branch has been further developed to incorporate application specific features for dynamic SIMS data sets. These include loading CAMECA IMS-1280, NanoSIMS and modified IMS-4f raw data, creating isotopic ratio images and stitching together images from adjacent interrogation regions. In addition to other modifications of the parent open source version, this version is equipped with a point-by-point image registration tool to assist with streamlining the image fusion process.

Analysis of the load selection on the error of source characteristics identification for an engine exhaust system

NASA Astrophysics Data System (ADS)

Zheng, Sifa; Liu, Haitao; Dan, Jiabi; Lian, Xiaomin

2015-05-01

Linear time-invariant assumption for the determination of acoustic source characteristics, the source strength and the source impedance in the frequency domain has been proved reasonable in the design of an exhaust system. Different methods have been proposed to its identification and the multi-load method is widely used for its convenience by varying the load number and impedance. Theoretical error analysis has rarely been referred to and previous results have shown an overdetermined set of open pipes can reduce the identification error. This paper contributes a theoretical error analysis for the load selection. The relationships between the error in the identification of source characteristics and the load selection were analysed. A general linear time-invariant model was built based on the four-load method. To analyse the error of the source impedance, an error estimation function was proposed. The dispersion of the source pressure was obtained by an inverse calculation as an indicator to detect the accuracy of the results. It was found that for a certain load length, the load resistance at the frequency points of one-quarter wavelength of odd multiples results in peaks and in the maximum error for source impedance identification. Therefore, the load impedance of frequency range within the one-quarter wavelength of odd multiples should not be used for source impedance identification. If the selected loads have more similar resistance values (i.e., the same order of magnitude), the identification error of the source impedance could be effectively reduced.

The Effects of Different External Carbon Sources on Nitrous Oxide Emissions during Denitrification in Biological Nutrient Removal Processes

NASA Astrophysics Data System (ADS)

Hu, Xiang; Zhang, Jing; Hou, Hongxun

2018-01-01

The aim of this study was to investigate the effects of two different external carbon sources (acetate and ethanol) on the nitrous oxide (N2O) emissions during denitrification in biological nutrient removal processes. Results showed that external carbon source significantly influenced N2O emissions during the denitrification process. When acetate served as the external carbon source, 0.49 mg N/L and 0.85 mg N/L of N2O was produced during the denitrificaiton processes in anoxic and anaerobic/anoxic experiments, giving a ratio of N2O-N production to TN removal of 2.37% and 4.96%, respectively. Compared with acetate, the amount of N2O production is negligible when ethanol used as external carbon addition. This suggested that ethanol is a potential alternative external carbon source for acetate from the point of view of N2O emissions.

Evaluating Aquatic Life Benefits of Reducing Nutrient Loading to Remediate Episodic and Diel Cycling Hypoxia in a Shallow Hypereutrophic Estuary

EPA Science Inventory

Theoretical linkages between excess nutrient loading, nutrient-enhanced community metabolism (i.e., production and respiration), and hypoxia in estuaries are well-understood. In seasonally-stratified estuaries and coastal systems (e.g., Chesapeake Bay, northern Gulf of Mexico), h...

Advances in fertilization for hardwood regeneration

Treesearch

Douglass F. Jacobs

2013-01-01

Optimizing fertilization programs in the nursery and field may help improve regeneration and restoration of temperate deciduous hardwoods. Our research program has demonstrated the applicability of nutrient loading in fine hardwood systems to promote seedling uptake and storage of nutrients during the nursery phase. We also have shown the benefits of nutrient loading...

Temporal and spatial variability in stable isotope compositions of a freshwater mussel: Implications for biomonitoring and ecological studies

USGS Publications Warehouse

Gustafson, L.; Showers, W.; Kwak, T.; Levine, J.; Stoskopf, M.

2007-01-01

Stable isotopes can be used to elucidate ecological relationships in community and trophic studies. Findings are calibrated against baselines, e.g. from a producer or primary consumer, assumed to act as a reference to the isotopic context created by spatio-temporal attributes such as geography, climate, nutrient, and energy sources. The ability of an organism to accurately represent a community base depends on how, and over what time-scale, it assimilates ambient materials. Freshwater mussels have served as references for trophic studies of freshwater communities and as indicators of change in nutrient pollution load or source. Their suitability as reference animals has not yet been fully explored, however. We conducted a series of studies examining the suitability of freshwater mussels as isotopic baselines, using their ability to reflect variation in ambient nutrient loads as a case scenario. (1) We analyzed bivalve foot tissue ??15N and ??13C from 22 stream reaches in the Piedmont region of North Carolina, USA to show that compositions varied substantially among locations. Site mean bivalve ??13C values correlated with site ambient particulate organic matter (POM) ??13C values, and site mean bivalve ??15N values correlated with site ambient water dissolved ??15N-NO3 values. (2) Similarity of results among sample types demonstrated that the minimally invasive hemolymph sample is a suitable substitute for foot tissue in ??15N analyses, and that small sample sizes generate means representative of a larger population. Both findings can help minimize the impact of sampling on imperiled freshwater mussel populations. (3) In a bivalve transplantation study we showed that hemolymph ??15N compositions responded to a shift in ambient dissolved ??15N-NO3, although slowly. The tissue turnover time for bivalve hemolymph was 113 days. We conclude that bivalves serve best as biomonitors of chronic, rather than acute, fluctuations in stream nutrient loads, and provide initial evidence of their suitability as time-integrated isotopic baselines for community studies. ?? 2006 Springer-Verlag.

Spatial Distribution of Nitrate in Mizoro-Ga a Pond with Floating at Bog

NASA Astrophysics Data System (ADS)

Shimamura, Tetsuya; Takemon, Yasuhiro; Osaka, Ken'ichi; Itoh, Masayuki; Ohte, Nobuhito

Artificial nutrient loading has been linked to the decrease in plant diversity in peatlands, riparian areas, and swamps. Mizoro-ga-ike pond is one of the natural monuments of Japan and contains temperate floating mat and diverse plant community. The pond had experienced eutrophication by sewage and tap water. As the inflows of nutrient-rich water had been lessened, the amount of source area of the pond has decreased to 30%. We investigated factors that control water chemistry in and around the pond to assess the present situation of the pond. The pond has two mouths of inflows. One of the inflows includes leaked water from a tap water reserver. The other is the surface flow collected by a ditch. The result of water quality census indicates the pond has two sources of nutrient-rich water. One is the drainage from the surface water polluted by the road for automobile that flows into the northern coast of the pond, and the other is the tap water-contaminated water entering from the southern coast. Also the result of the census indicates that emergent plants such as reeds and wild rice modify the effect of nutrient-rich water by exploiting nutrients. Especially, it was suggested that the nursery effects of emergent grasslands that spread southern part of the pond protect the less robust plants, Nuphar subintegerrimum.

Spatial Distribution of Nitrate in Mizoro-Ga a Pond with Floating Mat Bog

NASA Astrophysics Data System (ADS)

Shimamura, Tetsuya; Takemon, Yasuhiro; Osaka, Ken'ichi; Itoh, Masayuki; Ohte, Nobuhito

Artificial nutrient loading has been linked to the decrease in plant diversity in peatlands, riparian areas, and swamps. Mizoro-ga-ike pond is one of the natural monuments of Japan and contains temperate floating mat and diverse plant community. The pond had experienced eutrophication by sewage and tap water. As the inflows of nutrient-rich water had been lessened, the amount of source area of the pond has decreased to 30%. We investigated factors that control water chemistry in and around the pond to assess the present situation of the pond. The pond has two mouths of inflows. One of the inflows includes leaked water from a tap water reserver. The other is the surface flow collected by a ditch. The result of water quality census indicates the pond has two sources of nutrient-rich water. One is the drainage from the surface water polluted by the road for automobile that flows into the northern coast of the pond, and the other is the tap water-contaminated water entering from the southern coast. Also the result of the census indicates that emergent plants such as reeds and wild rice modify the effect of nutrient-rich water by exploiting nutrients. Especially, it was suggested that the nursery effects of emergent grasslands that spread southern part of the pond protect the less robust plants, Nuphar subintegerrimum.

Nitrogen speciation and phosphorus fractionation dynamics in a lowland Chalk catchment.

PubMed

Yates, C A; Johnes, P J

2013-02-01

A detailed analysis of temporal and spatial trends in nitrogen (N) speciation and phosphorus (P) fractionation in the Wylye, a lowland Chalk sub-catchment of the Hampshire Avon, UK is presented, identifying the sources contributing to nutrient enrichment, and temporal variability in the fractionation of nutrients in transit from headwaters to lower reaches of the river. Samples were collected weekly from ten monitoring stations with daily sampling at three further sites over one year, and monthly inorganic N and total reactive P (TRP) concentrations at three of the ten weekly monitoring stations over a ten year period are also presented. The data indicate significant daily and seasonal variation in nutrient fractionation in the water column, resulting from plant uptake of dissolved organic and inorganic nutrient fractions in the summer months, increased delivery of both N and P from diffuse sources in the autumn to winter period and during high flow events, and lack of dilution of point source discharges to the Wylye from septic tank, small package Sewage Treatment Works (STW) and urban Waste Water Treatment Works (WwTW) during the summer low flow period. Weekly data show that contributing source areas vary along the river with headwater N and P strongly influenced by diffuse inorganic N and particulate P fluxes, and SRP and organic-rich point source contributions from STW and WwTW having a greater influence in the lower reaches. Long-term data show a decrease in TRP concentrations at all three monitoring stations, with the most pronounced decrease occurring downstream from Warminster WwTW, following the introduction of P stripping at the works in 2001. Inorganic N demonstrates no statistically significant change over the ten year period of record in the rural headwaters, but an increase in the lower reaches downstream from the WwTW which may be due to urban expansion in the lower catchment. Copyright © 2012 Elsevier B.V. All rights reserved.

Effects of nutrient loading on the carbon balance of coastal wetland sediments

USGS Publications Warehouse

Morris, J.T.; Bradley, P.M.

1999-01-01

Results of a 12-yr study in an oligotrophic South Carolina salt marsh demonstrate that soil respiration increased by 795 g C m-2 yr-1 and that carbon inventories decreased in sediments fertilized with nitrogen and phosphorus. Fertilized plots became net sources of carbon to the atmosphere, and sediment respiration continues in these plots at an accelerated pace. After 12 yr of treatment, soil macroorganic matter in the top 5 cm of sediment was 475 g C m-2 lower in fertilized plots than in controls, which is equivalent to a constant loss rate of 40 g C m-2 yr-1. It is not known whether soil carbon in fertilized plots has reached a new equilibrium or continues to decline. The increase in soil respiration in the fertilized plots was far greater than the loss of sediment organic matter, which indicates that the increase in soil respiration was largely due to an increase in primary production. Sediment respiration in laboratory incubations also demonstrated positive effects of nutrients. Thus, the results indicate that increased nutrient loading of oligotrophic wetlands can lead to an increased rate of sediment carbon turnover and a net loss of carbon from sediments.

Nutrient loads of small-scale swine manure composting to groundwater and its prevention by covering: a case study.

PubMed

Cheng, Jianbo; Qiao, Junjing; Chen, Yucheng; Yang, Zhimin

2015-10-01

Small-scale composting is applied to recycle manure and biomass around the globe. Piles frequently site outside near field where bio-waste comes or compost goes within developing rural regions. However, little equipment or policy besides cover of common materials addressed concerns about its exposure to rainfall and subsequent leachate towards groundwater. In addition, little is known about its nutrient load to groundwater and covers' effect on nutrient unloading. Differently covered swine manure piles were composted outdoors with exposure to rain, then columns consisted of resultant compost of varying maturing age and soil were leached by simulated rainfall. Leachate TN, NH4 (+)-N, NO3 (-)-N, TP, and DP were modeled by regression analysis, and further, integral of quadratic curve or nutrient load index (NLI) was designated as proxy for nutrient load. Log response ratio was employed to qualify covers' effect on nutrient unloading. This case raised higher concern about leachate NH4 (+)-N than NO3 (-)-N for former's lower category in groundwater quality standard. The integrated NLIs or general nutrient load for six intervals, averagely divided from composting day of 60-120, decreased by 31, 37, 45, 56, and 73 % consecutively. Covers could unload nutrient to underground and function better to prevent P than N from leaching. Capabilities of piles covered by rice straw (CR) and soil (CS) to unload respectively are 77 and 72 % of by film (CF).