Science.gov

Sample records for nonpoint sources pollution

  1. Nonpoint Source Pollution.

    PubMed

    Ahmad, Zaki Uddin; Sakib, Salman; Gang, Daniel Dianchen

    2016-10-01

    Research advances on non-point source pollution in the year 2015 have been depicted in this review paper. Nonpoint source pollution is mainly caused by agricultural runoff, urban stormwater, and atmospheric deposition. Modeling techniques of NPS with different tools are reviewed in this article. PMID:27620104

  2. AGRICULTURAL NONPOINT SOURCE POLLUTION (AGNPS)

    EPA Science Inventory

    Developed by the USDA Agricultural Research Service, Agricultural Nonpoint Source Pollution (AGNPS) model addresses concerns related to the potential impacts of point and nonpoint source pollution on surface and groundwater quality (Young et al., 1989). It was designed to quantit...

  3. NON-POINT SOURCE POLLUTION

    EPA Science Inventory

    Non-point source pollution is a diffuse source that is difficult to measure and is highly variable due to different rain patterns and other climatic conditions. In many areas, however, non-point source pollution is the greatest source of water quality degradation. Presently, stat...

  4. [Review of urban nonpoint source pollution models].

    PubMed

    Wang, Long; Huang, Yue-Fei; Wang, Guang-Qian

    2010-10-01

    The development history of urban nonpoint source pollution models is reviewed. Features, applicability and limitations of seven popular urban nonpoint source pollution models (SWMM, STORM, SLAMM, HSPF, DR3M-QUAL, MOUSE, and HydroWorks) are discussed. The methodology and research findings of uncertainty in urban nonpoint source pollution modeling are presented. Analytical probabilistic models for estimation of urban nonpoint sources are also presented. The research achievements of urban nonpoint source pollution models in China are summarized. The shortcomings and gaps of approaches on urban nonpoint source pollution models are pointed out. Improvements in modeling of pollutants buildup and washoff, sediments and pollutants transport, and pollutants biochemical reactions are desired for those seven popular models. Most of the models developed by researchers in China are empirical models, so that they can only applied for specific small areas and have inadequate accuracy. Future approaches include improving capability in fate and transport simulation of sediments and pollutants, exploring methodologies of modeling urban nonpoint source pollution in regions with little data or incomplete information, developing stochastic models for urban nonpoint source pollution simulation, and applying GIS to facilitate urban nonpoint source pollution simulation. PMID:21229773

  5. Water Conservation and Nonpoint Source Pollution.

    ERIC Educational Resources Information Center

    Farrell-Poe, Kitt

    This book contains science activities that are designed to make learning and demonstrating nonpoint source pollution concepts exciting and fun. These activities can either be used alone or with an existing water resources education curricula. Activities include: Water Tasting, Acting Out the Hydrologic Cycle, Concentration of Chemical Pollutants…

  6. Nonpoint Sources.

    ERIC Educational Resources Information Center

    Browne, F. X.

    1978-01-01

    Presented a literature review of nonpoint source effects on water quality and pollution covering: (1) water quality effects; (2) watershed studies; (3) nonpoint source models; and nonpoint source controls. A list of 122 references published in 1976 and 1977 is also presented. (HM)

  7. Controlling Nonpoint-Source Water Pollution: A Citizen's Handbook.

    ERIC Educational Resources Information Center

    Hansen, Nancy Richardson; And Others

    Citizens can play an important role in helping their states develop pollution control programs and spurring effective efforts to deal with nonpoint-source pollution. This guide takes the reader step-by-step through the process that states must follow to comply with water quality legislation relevant to nonpoint-source pollution. Part I provides…

  8. Nonpoint sources

    SciTech Connect

    Selzer, L.

    1994-12-31

    Nonpoint source pollution remains the most pervasive water quality issue faced today. Unlike pollution from point sources, nonpoint source pollution is diffuse both in terms of its origin and the manner in which it enters ground and surface waters. It results from a great variety of human activities that take place over a wide geographic area perhaps many hundreds or even thousands of acres. And unlike pollutants from point sources--which enter the environment at well-defined locations and in relatively even, continuous discharges--pollutants from nonpoint sources usually find their way into surface and ground waters in sudden surges associated with rainfall, thunderstorms, or snowmelt. The author discusses some of the most significant sources of nonpoint source pollution.

  9. ALTERNATIVE POLICIES FOR CONTROLLING NONPOINT AGRICULTURAL SOURCES OF WATER POLLUTION

    EPA Science Inventory

    This study of policies for controlling water pollution from nonpoint agricultural sources includes a survey of existing state and Federal programs, agencies, and laws directed to the control of soil erosion. Six policies representing a variety of approaches to this pollution prob...

  10. Mining-related nonpoint-source pollution

    SciTech Connect

    Cohen, R.H.; Gorman, J. )

    1991-06-01

    This article describes the effects of increased mining activity on surface and groundwater. The topics covered include pollutant sources, contaminant transport and fate, trace element toxicity, pollution control and abatement, treating acid mine drainage, modern constructed wetlands and site reclamation including site stabilization, refuse burial and sludge application.

  11. Biodetention: A best management practice for nonpoint source pollution

    SciTech Connect

    Murfee, G.; Scaief, J.; Whelan, M.

    1998-07-01

    Biodetention is an innovative nonpoint source (NPS) pollution control best management practice (BMP) developed as an alternative to sedimentation/filtration ponds. Biodetention is applicable as a runoff treatment system for concentrated point discharges from stormwater collection facilities. Treatment is facilitated by vegetative filter strips and stiff grass hedges.

  12. RECOGNIZING FARMERS' ATTITUDES AND IMPLEMENTING NONPOINT SOURCE POLLUTION CONTROL POLICIES

    EPA Science Inventory

    This report examines the role of farmer attitudes and corresponding communication activities in the implementation of nonpoint source water pollution control programs. The report begins with an examination of the basis for and function of attitudes in influencing behavior. The ro...

  13. Control of Agricultural Nonpoint Source Pollution by Natural Wetland Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reduction of nonpoint source pollutants, principally sediment and nutrients moving from cultivated fields to surface waters, is a major challenge. Remnants of once-extensive natural wetlands occur across the agricultural landscape, and some workers have suggested that these areas might be managed t...

  14. Tracking nonpoint source nitrogen pollution in human-impacted watersheds

    USGS Publications Warehouse

    Kaushal, S.S.; Groffman, P.M.; Band, L.E.; Elliott, E.M.; Shields, C.A.; Kendall, C.

    2011-01-01

    Nonpoint source nitrogen (N) pollution is a leading contributor to U.S. water quality impairments. We combined watershed N mass balances and stable isotopes to investigate fate and transport of nonpoint N in forest, agricultural, and urbanized watersheds at the Baltimore Long-Term Ecological Research site. Annual N retention was 55%, 68%, and 82% for agricultural, suburban, and forest watersheds, respectively. Analysis of ?? 15N-NO3-, and ??18O-NO 3- indicated wastewater was an important nitrate source in urbanized streams during baseflow. Negative correlations between ??15N-NO3- and ??18O- NO3- in urban watersheds indicated mixing between atmospheric deposition and wastewater, and N source contributions changed with storm magnitude (atmospheric sources contributed ???50% at peak storm N loads). Positive correlations between ??15N-NO3- and ??18O-NO3- in watersheds suggested denitrification was removing septic system and agriculturally derived N, but N from belowground leaking sewers was less susceptible to denitrification. N transformations were also observed in a storm drain (no natural drainage network) potentially due to organic carbon inputs. Overall, nonpoint sources such as atmospheric deposition, wastewater, and fertilizer showed different susceptibility to watershed N export. There were large changes in nitrate sources as a function of runoff, and anticipating source changes in response to climate and storms will be critical for managing nonpoint N pollution. ?? 2011 American Chemical Society.

  15. Emerging policies to control nonpoint source pollution of groundwater

    NASA Astrophysics Data System (ADS)

    Harter, T.

    2014-12-01

    Water quality impairment is among the highest ranking public issues of concern in the developed world. While, in Europe and North America, many water quality programs have been put in place over the past half century, regulators difficulties tackling the geographically most widespread water quality degradation in these regions: pollution of groundwater (as opposed to surface water) from diffuse sources (as opposed to point sources), including contamination with nitrate (affecting drinking water supplies in rural areas and at the rural-urban interface) and salinity (affecting irrigation water quality). Other diffuse pollution contaminants include pesticides and emerging contaminants (e.g., antibiotics and pathogens from animal farming). The geographic and hydrologic characteristics of nonpoint source pollution of groundwater are distinctly different from other types of water pollution: individually liable sources are contiguous across the landscape, and internally heterogeneous in space and time. On annually aggregated time scales (most relevant to groundwater), sources are continuously emitting pollution, while pollution levels typically do not exceed MCLs by less than a factor 2. An analysis of key elements of existing water pollution policies to control groundwater pollution from diffuse sources demonstrates the lack of both, science and institutional capacity, while existing point-source approaches cannot be applied toward the control of diffuse pollution to groundwater. For the latter, a key to a successful policy is a tiered, three-way monitoring program based on proxy compliance metrics instead of direct measurement of pollutant discharge, research linking actual pollutant discharges to proxy metrics, and long-term regional groundwater monitoring to establish large scale, long-term trends. Several examples of emerging regulations from California and the EU are given to demonstrate these principles.

  16. Introduction to nonpoint-source pollution and wetland mitigation

    SciTech Connect

    Baker, L.A.

    1991-09-12

    Nonpoint source pollution (NPS) is the major cause of impairment of U.S. surface waters. Erosion from croplands has been declining but is not yet reflected in decreased sediment yield or phosphorus concentrations in the nation's rivers. Nitrogen pollution is of particular concern in eutophication of estuaries as a contaminant of groundwater, and as an acidifying agent in atmospheric deposition. Nitrogen fertilizer and emissions of nitrous oxides are major contributors to the problem. The outlook on pesticides is mixed: bans on organochlorine pesticides in the 1970s have resulted in decreasing concentrations in fish tissue; however, herbicides are now a problem for some surface and groundwater sources of drinking water, especially in the Upper Midwest.

  17. OPTIMAL MANAGEMENT OF NON-POINT SOURCE POLLUTION FROM AGRICULTURE: AN APPLICATION OF DYNAMIC PROGRAMMING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural non-point source pollution is a major source of water quality impairment. When considering responses to non-point source pollution, several policy options have been considered historically, including reducing inputs (e.g. fertilizers) altering technologies on the landscape (e.g. conserv...

  18. NATIONAL MANAGEMENT MEASURES TO CONTROL NONPOINT SOURCE POLLUTION FROM HYDROMODIFICATION

    EPA Science Inventory

    Hydromodification What Are the Nonpoint Source-Related Problems Associated with Hydromodification? Hydromodification activities have been separated into the categories of channelization and channel modification, dams, and streambank and shoreline erosion. A frequent result of c...

  19. Costs and water quality effects of controlling point and nonpoint pollution sources

    SciTech Connect

    Macal, C.M.; Broomfield, B.J.

    1980-01-01

    Costs and water quality effects of controlling point and nonpoint pollution sources are compared for the DuPage River basin in northern Illinois. Costs are estimated for effluent standards for municipal wastewater treatment plants and for the alternative, controlling runoff from nonpoint sources such as streets, agricultural lands, and forests. A dynamic water-quality/hydrology simulation model is used to determine water quality effects of various treatment plant standards and nonpoint-source controls. Costs and water quality data are combined, and the point-source and nonpoint-source plans are compared on a cost-effectiveness basis. Nonpoint-source controls are found to be more cost-effective than stricter control of pollutants from point sources.

  20. Snowmelt runoff: a new focus of urban nonpoint source pollution.

    PubMed

    Zhu, Hui; Xu, Yingying; Yan, Baixing; Guan, Jiunian

    2012-12-01

    Irregular precipitation associated with global climate change had been causing various problems in urban regions. Besides the runoff due to rainfall in summer, the snowmelt runoff in early spring could also play an important role in deteriorating the water quality of the receiving waters. Due to global climate change, the snowfall has increased gradually in individual regions, and snowstorms occur more frequently, which leads to an enhancement of snowmelt runoff flow during the melting seasons. What is more, rivers just awaking from freezing constitute a frail ecosystem, with poor self-purification capacity, however, the urban snowmelt runoff could carry diverse pollutants accumulated during the winter, such as coal and/or gas combustion products, snowmelting agents, automotive exhaust and so on, which seriously threaten the receiving water quality. Nevertheless, most of the research focused on the rainfall runoff in rainy seasons, and the study on snowmelt runoff is still a neglected field in many countries and regions. In conclusion, due to the considerable water quantity and the worrisome water quality, snowmelt runoff in urban regions with large impervious surface areas should be listed among the important targets in urban nonpoint source pollution management and control. PMID:23202881

  1. Snowmelt Runoff: A New Focus of Urban Nonpoint Source Pollution

    PubMed Central

    Zhu, Hui; Xu, Yingying; Yan, Baixing; Guan, Jiunian

    2012-01-01

    Irregular precipitation associated with global climate change had been causing various problems in urban regions. Besides the runoff due to rainfall in summer, the snowmelt runoff in early spring could also play an important role in deteriorating the water quality of the receiving waters. Due to global climate change, the snowfall has increased gradually in individual regions, and snowstorms occur more frequently, which leads to an enhancement of snowmelt runoff flow during the melting seasons. What is more, rivers just awaking from freezing cosntitute a frail ecosystem, with poor self-purification capacity, however, the urban snowmelt runoff could carry diverse pollutants accumulated during the winter, such as coal and/or gas combustion products, snowmelting agents, automotive exhaust and so on, which seriously threaten the receiving water quality. Nevertheless, most of the research focused on the rainfall runoff in rainy seasons, and the study on snowmelt runoff is still a neglected field in many countries and regions. In conclusion, due to the considerable water quantity and the worrisome water quality, snowmelt runoff in urban regions with large impervious surface areas should be listed among the important targets in urban nonpoint source pollution management and control. PMID:23202881

  2. Management of agricultural nonpoint source pollution in China: current status and challenges.

    PubMed

    Wang, Xiaoyan

    2006-01-01

    Water quality in China shows an overall trend of deterioration in recent years. Nonpoint source pollution from agricultural and rural regions is the leading source of water pollution. The agricultural nonpoint source pollutants are mainly from fertilization of cropland, excessive livestock and poultry breeding and undefined disposal of daily living wastes in rural areas. Agricultural nonpoint sources contribute the main source of pollution to most watersheds in China, but they are ignored in management strategy and policy. Due to the lack of full understanding of water pollution control and management and the lack of perfect water quality standard systems and practical legislative regulations, agricultural nonpoint source pollution will become one of the biggest challenges to the sustainable development of rural areas and to society as a whole. The system for agricultural nonpoint source pollution control in China should include an appropriate legislation and policy framework, financing mechanisms, monitoring system, and technical guidelines and standards. The management of agricultural nonpoint source pollution requires multidisciplinary approaches that will involve a range of government departments, institutions and the public. PMID:16594318

  3. Simulation of Non-point Source Pollution in the Songhua River Basin Using GBNP Model

    NASA Astrophysics Data System (ADS)

    Pan, J.; Tang, L.; Chen, Y. D.

    2015-12-01

    China is facing increasingly severe water pollution issue with rapid socio-economic development. Non-point source pollution, which is rarely monitored, has become the main forms of water pollution in China. In this study, the Geomorphology-Based Non-point source Pollution (GBNP) model was used to simulate the processes of rain-runoff, soil erosion, sediment routing and pollutant transport in the Songhua River basin from 2001 to 2010. The spatio-temporal variation of non-point source pollution and river water quality were analyzed based on the simulation outputs. In the entire basin, the annual mean loading of TN, TP and soil erosion are 270,000 ton/a, 42,200 ton/a and 55,900,000 ton/a, respectively. The point and non-point source pollution respectively account for 44.9% and 55.1% in TN loading. For TP loading, the proportions of point and non-point source pollution are 14.4% and 85.6%, respectively. It suggests that the non-point source pollution control and treatments should be paid more attention in the Songhua River basin. The inter-annual and intra-annual variations of non-point source pollution components and potential driving mechanisms are further examined. The annual loading of soil erosion, TN and TP are highly correlated with annual runoff, with the correlation coefficients of 0.75, 0.91 and 0.92, respectively, which implies that rain-runoff could be the main driving force of non-point pollution. The monthly sediment concentration in the watercourse is high in flood season and low in non-flood season, which agrees well with the seasonality of monthly runoff. By contrast, the concentrations of TN and TP in watercourse show the opposite features.

  4. UNCERTAINTY IN LEACHING POTENTIAL OF NONPOINT SOURCE POLLUTANTS WITH APPLICATION TO A GIS

    EPA Science Inventory

    This paper presents a stochastic framework for the assessment of groundwater pollution potential of nonpoint source pesticides. A conceptual relationship is presented that relates seasonally averaged groundwater recharge to soil properties and depths to the water table. The analy...

  5. Agroforestry buffers for nonpoint source pollution reductions from agricultural watersheds.

    PubMed

    Udawatta, Ranjith P; Garrett, Harold E; Kallenbach, Robert

    2011-01-01

    Despite increased attention and demand for the adoption of agroforestry practices throughout the world, rigorous long-term scientific studies confirming environmental benefits from the use of agroforestry practices are limited. The objective was to examine nonpoint-source pollution (NPSP) reduction as influenced by agroforestry buffers in watersheds under grazing and row crop management. The grazing study consists of six watersheds in the Central Mississippi Valley wooded slopes and the row crop study site consists of three watersheds in a paired watershed design in Central Claypan areas. Runoff water samples were analyzed for sediment, total nitrogen (TN), and total phosphorus (TP) for the 2004 to 2008 period. Results indicate that agroforestry and grass buffers on grazed and row crop management sites significantly reduce runoff, sediment, TN, and TP losses to streams. Buffers in association with grazing and row crop management reduced runoff by 49 and 19%, respectively, during the study period as compared with respective control treatments. Average sediment loss for grazing and row crop management systems was 13.8 and 17.9 kg ha yr, respectively. On average, grass and agroforestry buffers reduced sediment, TN, and TP losses by 32, 42, and 46% compared with the control treatments. Buffers were more effective in the grazing management practice than row crop management practice. These differences could in part be attributed to the differences in soils, management, and landscape features. Results from this study strongly indicate that agroforestry and grass buffers can be designed to improve water quality while minimizing the amount of land taken out of production. PMID:21546665

  6. The economic impact of remote sensing data as the source of nonpoint pollution monitoring and control

    NASA Technical Reports Server (NTRS)

    Miller, W. L.

    1974-01-01

    Nonpoint pollution of streams with sediment as a result of runoff from alternative uses of land has become a socially unacceptable product of economic activity. This report describes a research approach to economically achieve correction of the nonpoint pollution problem. The research approach integrates the economic model with those data which may be obtainable from remotely sensed sources. The economic problem involves measurement of the direct benefits and costs associated with the changes in land management activities necessary to reduce the level of nonpoint pollution. Remotely sensed data from ERTS-1 may provide some of the information required for the economic model which indicates efficient solutions to the nonpoint pollution problem. Three classes of data (i.e., soil categories, vegetative cover, and water turbidity) have the potential to be measured by ERTS-1 systems. There is substantial research which indicates the ability of ERTS-1 to measure these classes of data under selected conditions.

  7. Predicting precipitation on nonpoint source pollutant exports in the source area of the Liao River, China.

    PubMed

    Wang, Y; Bian, J M; Wang, S N; Nie, S Y

    2016-01-01

    The source area of the Liao River is an important grain growing area in China which experiences serious problems with agricultural nonpoint source pollution (NPS) which is impacting the regional economy and society. In order to address the water quality issues it is necessary to understand the spatial distribution of NPS in the Liao River source area. This issue has been investigated by coupling a wavelet artificial neural network (WA-ANN) precipitation model with a soil and water assessment tool (SWAT) model to assess the export of nonpoint source pollutants from the Liao River source area. The calibration and validation of these models are outlined. The WA-ANN models and the SWAT model were run to generate the spatial distribution of nonpoint source nutrient (nitrogen and phosphorus) exports in the source area of the Liao River. It was found that the SWAT model identified the sub-catchments which not only receive high rainfall but are also densely populated with high agricultural production from dry fields and paddy fields, which are large users of pesticides and chemical fertilizer, as the primary source areas for nutrient exports. It is also concluded that the coupled WA-ANN models and the SWAT model provide a tool which will inform the identification of NPS issues and will facilitate the identification of management practices to improve the water environments in the source area of the Liao River. PMID:27533862

  8. Feasibility of point-nonpoint source trading for managing agricultural pollutant loadings to coastal waters

    NASA Astrophysics Data System (ADS)

    Crutchfield, Stephen R.; Letson, David; Malik, Arun S.

    1994-10-01

    A recent focus of water quality policy discussions has been the trading of pollution abatement between point and nonpoint sources. Point-nonpoint trading would allow point sources to sponsor nonpoint source controls rather than install further controls of their own. If nonpoint source loadings are significant and the marginal costs of their control are lower than for additional point source controls, water quality goals could be met at lower cost with trading. We isolate difficulties particular to incentive policies such as point-nonpoint trading and then screen coastal watersheds for those satisfying conditions that play a major role in determining whether trading can improve water quality. We follow the recent Coastal Zone Act Reauthorization Amendments in emphasizing agriculture, the single largest cause of nonpoint source pollution. Our screening analysis provides an initial, empirical assessment of the feasibility of trading for managing agricultural land use to protect coastal water quality. We also illustrate the additional analysis required to quantify the potential for successful trading in those watersheds which meet our screening criteria.

  9. Simulation of Urban Runoff Non-point Source Pollution Load and Analysis on Its Influencing Factors

    NASA Astrophysics Data System (ADS)

    Li, R.; Ruan, X.

    2013-12-01

    As the point source pollution control has advanced, the proportion of urban non-point pollution caused by rainfall in urban water pollution is increasing. For quantitative evaluation of non-point source pollution in urban rivers and to study their influencing factors, this study takes the inner Qinhuai River in Nanjing as the study area. The non-point source pollution load simulation model of the study area was built based on the Storm Water Management Model (SWMM), and was calibrated using the real-time monitoring data of rainfall and the outlet of the pipes during a short duration rainfall in 2011. TSS, CODMn, TN and TP were selected as the major pollution load indicators to quantitatively assess the rainfall runoff and non-point source pollution of 328.2ha confluence area of inner Qinhuai River, emphatically probe into the variation of the rainfall runoff and non-point source pollution in response to variability in underlying surface and drainage pipes. The results show that: (1) the pollution load concentration in the outlet of the popes increases initially and then decreases, the peak concentration appears at 5~15minutes after the effluent. The concentration of TN and TP appears apparent randomness and fluctuation due to the spatial-temporal uncertainty of the distribution of the non-point source pollution. The maximum flow into the river, the total runoff, the total output of TSS, CODMn, TN and TP during a typical year rainfall in two years return period are 19.67m3/s, 81.74×103m3, 2318.59kg, 1598.08kg, 476.09kg and 24.24kg, respectively. (2)The percentage of impervious underlying surface, the slope of the underlying surface, the percentage of no depression of the impervious underlying surface and the roughness of the pipes, which are the sensitive parameters of the model, have an significant impact on the runoff and pollution load in the outlet of the pipes. Urban rainfall runoff and non-point source pollution can be reduced by reducing the percentage of

  10. Nonpoint source pollution of urban stormwater runoff: a methodology for source analysis.

    PubMed

    Petrucci, Guido; Gromaire, Marie-Christine; Shorshani, Masoud Fallah; Chebbo, Ghassan

    2014-09-01

    The characterization and control of runoff pollution from nonpoint sources in urban areas are a major issue for the protection of aquatic environments. We propose a methodology to quantify the sources of pollutants in an urban catchment and to analyze the associated uncertainties. After describing the methodology, we illustrate it through an application to the sources of Cu, Pb, Zn, and polycyclic aromatic hydrocarbons (PAH) from a residential catchment (228 ha) in the Paris region. In this application, we suggest several procedures that can be applied for the analysis of other pollutants in different catchments, including an estimation of the total extent of roof accessories (gutters and downspouts, watertight joints and valleys) in a catchment. These accessories result as the major source of Pb and as an important source of Zn in the example catchment, while activity-related sources (traffic, heating) are dominant for Cu (brake pad wear) and PAH (tire wear, atmospheric deposition). PMID:24760596

  11. Nonpoint Source Pollution: Agriculture, Forestry, and Mining. Instructor Guide. Working for Clean Water: An Information Program for Advisory Groups.

    ERIC Educational Resources Information Center

    Buskirk, E. Drannon, Jr.

    Nonpoint sources of pollution have diffuse origins and are major contributors to water quality problems in both urban and rural areas. Addressed in this instructor's manual are the identification, assessment, and management of nonpoint source pollutants resulting from mining, agriculture, and forestry. The unit, part of the Working for Clean Water…

  12. SIMULATION COASTAL PLAIN STREAM FISH COMMUNITY RESPONSE TO NONPOINT SOURCE POLLUTION USING LINKED HYDROLOGIC-ECOLOGICAL MODELS

    EPA Science Inventory

    Nonpoint source pollution is the primary stress in many streams. Characteristic declines in stream fish communities are recognized in streams influenced by nonpoint source pollution, but the processes by which these declines occur are not well understood. Here, predicted time s...

  13. Management of an Abandoned River Channel Wetland for Mitigation of Nonpoint Source Pollution

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reduction of nonpoint source pollutants, principally sediment and nutrients moving from cultivated fields to surface waters, is a major challenge. Remnants of once-extensive natural wetlands occur across the agricultural landscape, and some workers have suggested that these areas might be managed t...

  14. Nonpoint-Source Pollution Issues. January 1990-November 1994. QB 95-01. Quick Bibliography Series.

    ERIC Educational Resources Information Center

    Makuch, Joe

    Citations in this bibliography are intended to be a substantial resource for recent investigations (January 1990-November 1994) on nonpoint source pollution and were obtained from a search of the National Agriculture Library's AGRICOLA database. The 196 citations are indexed by author and subject. A representation of the search strategy is…

  15. BOOK REVIEW OF "ASSESSMENT AND CONTROL OF NONPOINT SOURCE POLLUTION OF AQUATIC ECOSYSTEMS: A PRACTICAL APPROACH"

    EPA Science Inventory

    This book is geared to environmental specialists and planners, heavy on the technical side. It goes beyond tranditional nonpoint source (NPS) approaches which typically only look at stormwater as athe sole NPS pollution driver. There is some overreaching material beyond the conte...

  16. Advanced information technologies for assessing nonpoint source pollution in the vadose zone: Conference overview

    SciTech Connect

    Corwin, D.L.; Loague, K.; Ellsworth, T.R.

    1999-03-01

    The information age has ushered in an awareness of and concern for global environmental problems such as climatic change, ozone depletion, deforestation, desertification, and nonpoint source (NPS) pollution. Nonpoint source pollution is the single greatest threat to surface and subsurface drinking water resources. Nonpoint source pollutants also pose a threat to sustainable agriculture, which is viewed as the most viable means of meeting the food demands of a world population that is expected to reach 9.4 billion by the middle of the next century. The ability to accurately assess present and future NPS pollution impacts on ecosystems ranging from local to global scales would provide a powerful tool for environmental stewardship and guiding future human activities. Assessing NPS pollutant is a multidisciplinary problem. To address the problem, advanced information technologies and methodologies are needed that draw from all areas of science and are applied in a spatial context. It was from this setting that the 1997 Joint AGU Chapman/SSSA Outreach Conference Application of GIS, Remote Sensing, Geostatistics, and Solute Transport Modeling for Assessing Nonpoint Source Pollutants in the Vadose Zone (19--24 Oct. 1997, Riverside, CA) materialized. The objective of the conference was to examine current multidisciplinary technologies and methodologies for assessing NPS pollutants in the vadose zone, and to explore new conceptual approaches. It was the conference`s goal to provide a forum to stimulate multidisciplinary interaction to enhance the development of techniques for the real-time measurement and modeling of NPS pollution in the vadose zone and subsurface waters.

  17. Evaluation of Nonpoint Source Pollution in Stormwater Run-Off in Neighborhoods in San Francisco, California

    NASA Astrophysics Data System (ADS)

    Bailey, C.; Bailey, E.; Cai, W.; Chen, K.; Duario, D.; Gonzalez, S.; Li, A.; Liu, L. W.; Matic, M.; Wu, M. L.; Wu, X. P.; Xie, J.; Yue, J.; Yuen, K.; Kirwin, J. P.; Neiss, J.

    2007-12-01

    This is the San Francisco Bay watershed encompasses 40% of California. When precipitation occurs, nonpoint source pollutants such as fertilizers, heavy metals, pesticides, gas and oil, enter the San Francisco Bay through this watershed. These pollutants contain dangerous chemicals that can potentially impact people and local ecology. The goal of Project Watershed is for high school students to design a study that investigates nonpoint source pollution in their own neighborhood and correlate these findings to the human activity in the neighborhood. Fifteen high school students participating in this study designed a stormwater collection devise that was installed in the public storm drain near each students home. Stormwater samples where collected from each device during the period of December 2006 to April 2007. Students assessed the samples for nitrates, heavy metals, oil and grease, total petroleum hydrocarbons, toluene and methyl tert-butyl ether (MTBE). This study outlines the methods students used to design the study and a summary of results found.

  18. Spatiotemporal nonpoint source pollution water quality management framework using bi-directional model-GIS linkage

    SciTech Connect

    Faizullabhoy, M.S.; Yoon, J.

    1999-07-01

    A framework for water quality assessment and management purposes was developed. In this framework, a bilateral linkage was implemented between the distributed model, Agricultural Nonpoint Source Pollution Model (AGNPS) and the Geographic Information System (GIS) to investigate a spatiotemporal nonpoint source pollution problem from a 750-acre watershed in the NSGA (Naval Security Group Activity) Northwest base at the Virginia/North Carolina border. AGNPS is an event-based, distributed parameter model that simulates runoff and the transport of sediment and nutrients (nitrogen and phosphorus) from predominantly agricultural watersheds. In this study rather than manually implementing AGNPS simulation, extracted data are integrated in an automated fashion through a direct bilateral linkage framework between the AGNPS model engine and the GIS. This bilateral linkage framework resulted in a powerful, up-to-date tool that would be capable of monitoring and instantaneously visualizing the transport of any pollutant as well as effectively identifying critical areas of the nonpoint source (NPS) pollution. The framework also allowed the various what if scenarios to support the decision-making processes. Best Management Practices (BMP) for the watershed can be generated in a close loop iterative scheme, until predefined management objectives are achieved. Simulated results showed that the optimal BMP scenario achieved an average reduction of about 41% in soluble and sediment-attached nitrogen and about 62% reduction in soluble and sediment phosphorus from current NPS pollution levels.

  19. Nonpoint source groundwater pollution and endogenous regulatory policies

    NASA Astrophysics Data System (ADS)

    Lee, Donna J.; Kim, C. S.

    2002-12-01

    Theory suggests that in the absence of transaction costs, pollution externalities can be mitigated efficiently by charging polluters a tax equal to the marginal social cost of pollution. All other regulatory mechanisms therefore may be no more efficient than a marginal cost pollution tax. We developed a stylized model of dynamic groundwater pollution without transaction costs to examine alternate policies. Using mitigation cost, tax burden, and excess burden we compared the relative efficiency of each tax policy under competitive market conditions. For groundwater nitrate pollution in a Midwestern farming region, results show that the least cost policy is a constant tax on the polluting input, followed by a variable tax on the polluting input and a pollution tax.

  20. Spreadsheet WATERSHED modeling for nonpoint-source pollution management in a Wisconsin basin

    USGS Publications Warehouse

    Walker, J.F.; Pickard, S.A.; Sonzogni, W.C.

    1989-01-01

    Although several sophisticated nonpoint pollution models exist, few are available that are easy to use, cover a variety of conditions, and integrate a wide range of information to allow managers and planners to assess different control strategies. Here, a straightforward pollutant input accounting approach is presented in the form of an existing model (WATERSHED) that has been adapted to run on modern electronic spreadsheets. As an application, WATERSHED is used to assess options to improve the quality of highly eutrophic Delavan Lake in Wisconsin. WATERSHED is flexible in that several techniques, such as the Universal Soil Loss Equation or unit-area loadings, can be used to estimate nonpoint-source inputs. Once the model parameters are determined (and calibrated, if possible), the spreadsheet features can be used to conduct a sensitivity analysis of management options. In the case of Delavan Lake, it was concluded that, although some nonpoint controls were cost-effective, the overall reduction in phosphorus would be insufficient to measurably improve water quality.A straightforward pollutant input accounting approach is presented in the form of an existing model (WATERSHED) that has been adapted to run on modern electronic spreadsheets. As an application, WATERSHED is used to assess options to improve the quality of highly eutrophic Delavan Lake in Wisconsin. WATERSHED is flexible in that several techniques, such as the Universal Soil Loss Equation or unit-area loadings, can be used to estimate nonpoint-source inputs. Once the model parameters are determined (and calibrated, if possible), the spreadsheet features can be used to conduct a sensitivity analysis of management options. In the case of Delavan Lake, it was concluded that, although some nonpoint controls were cost-effective, the overall reduction in phosphorus would be insufficient to measurably improve water quality.

  1. Landscape Planning for Agricultural Nonpoint Source Pollution Reduction I: A Geographical Allocation Framework

    NASA Astrophysics Data System (ADS)

    Diebel, Matthew W.; Maxted, Jeffrey T.; Nowak, Peter J.; Vander Zanden, M. Jake

    2008-11-01

    Agricultural nonpoint source pollution remains a persistent environmental problem, despite the large amount of money that has been spent on its abatement. At local scales, agricultural best management practices (BMPs) have been shown to be effective at reducing nutrient and sediment inputs to surface waters. However, these effects have rarely been found to act in concert to produce measurable, broad-scale improvements in water quality. We investigated potential causes for this failure through an effort to develop recommendations for the use of riparian buffers in addressing nonpoint source pollution in Wisconsin. We used frequency distributions of phosphorus pollution at two spatial scales (watershed and field), along with typical stream phosphorus (P) concentration variability, to simulate benefit/cost curves for four approaches to geographically allocating conservation effort. The approaches differ in two ways: (1) whether effort is aggregated within certain watersheds or distributed without regard to watershed boundaries (dispersed), and (2) whether effort is targeted toward the most highly P-polluting fields or is distributed randomly with regard to field-scale P pollution levels. In realistic implementation scenarios, the aggregated and targeted approach most efficiently improves water quality. For example, with effort on only 10% of a model landscape, 26% of the total P load is retained and 25% of watersheds significantly improve. Our results indicate that agricultural conservation can be more efficient if it accounts for the uneven spatial distribution of potential pollution sources and the cumulative aspects of environmental benefits.

  2. Managing Nonpoint Source Pollution in Western Washington: Landowner Learning Methods and Motivations

    NASA Astrophysics Data System (ADS)

    Ryan, Clare M.

    2009-06-01

    States, territories, and tribes identify nonpoint source pollution as responsible for more than half of the Nation’s existing and threatened water quality impairments, making it the principal remaining cause of water quality problems across the United States. Combinations of education, technical and financial assistance, and regulatory measures are used to inform landowners about nonpoint source pollution issues, and to stimulate the use of best management practices. A mail survey of non-commercial riparian landowners investigated how they learn about best management practices, the efficacy of different educational techniques, and what motivates them to implement land management activities. Landowners experience a variety of educational techniques, and rank those that include direct personal contact as more effective than brochures, advertisements, radio, internet, or television. The most important motivations for implementing best management practices were linked with elements of a personal stewardship ethic, accountability, personal commitment, and feasibility. Nonpoint source education and social marketing campaigns should include direct interpersonal contacts, and appeal to landowner motivations of caring, responsibility, and personal commitment.

  3. [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. PMID:23745390

  4. Assessment of Non-Point Source Pollution in the Vadose Zone

    NASA Astrophysics Data System (ADS)

    Corwin, L.; Loague, Keith; Ellsworth, R.

    Non-point source (NPS) pollution in the vadose zone (simply defined as the layer of soil extending from the soil surface to the groundwater table) is a global environmental problem. Characteristically, NPS pollutants are widespread and occasionally ubiquitous in extent, thus making remediation efforts difficult and complex; have the potential for maintaining a relatively long active presence in the global ecosystem; and may result in long-term, chronic health effects in humans and other life forms. Similar to other global environmental issues, the knowledge and information required to address the problem of NPS pollutants in the vadose zone cross several technological and subdisciplinary lines: spatial statistics, geographic information systems (GIS), hydrology, soil science, and remote sensing. Cooperation between disciplines and scientific societies is essential to address the problem. Evidence of such cooperation was the jointly sponsored American Geophysical Union Chapman/Soil Science Society of America (SSSA) Outreach Conference that occurred in October 1997, entitled "Applications of GIS, Remote Sensing, Geostatistics, and Solute Transport Modeling to the Assessment of Non-Point Source Pollution in the Vadose Zone." The objective of the conference and this book, which was developed from the conference, was to explore current multidisciplinary research for assessing NPS pollution in soil and groundwater resources.

  5. Uncertainty Analysis of non-point source pollution control facilities design techniques in Korea

    NASA Astrophysics Data System (ADS)

    Lee, J.; Okjeong, L.; Gyeong, C. B.; Park, M. W.; Kim, S.

    2015-12-01

    The design of non-point sources control facilities in Korea is divided largely by the stormwater capture ratio, the stormwater load capture ratio, and the pollutant reduction efficiency of the facility. The stormwater capture ratio is given by a design formula as a function of the water quality treatment capacity, the greater the capacity, the more the amount of stormwater intercepted by the facility. The stormwater load capture ratio is defined as the ratio of the load entering the facility of the total pollutant load generated in the target catchment, and is given as a design formula represented by a function of the stormwater capture ratio. In order to estimate the stormwater capture ratio and load capture ratio, a lot of quantitative analysis of hydrologic processes acted in pollutant emission is required, but these formulas have been applied without any verification. Since systematic monitoring programs were insufficient, verification of these formulas was fundamentally impossible. However, recently the Korean ministry of Environment has conducted an long-term systematic monitoring project, and thus the verification of the formulas became possible. In this presentation, the stormwater capture ratio and load capture ratio are re-estimated using actual TP data obtained from long-term monitoring program at Noksan industrial complex located in Busan, Korea. Through the re-estimated process, the uncertainty included in the design process that has been applied until now will be shown in a quantitative extent. In addition, each uncertainty included in the stormwater capture ratio estimation and in the stormwater load capture ratio estimation will be expressed to quantify the relative impact on the overall non-point pollutant control facilities design process. Finally, the SWMM-Matlab interlocking module for model parameters estimation will be introduced. Acknowledgement This subject is supported by Korea Ministry of Environment as "The Eco Innovation Project : Non-point

  6. Stochastic Assessment of Regional Groundwater Nonpoint Source Pollution with Spatially Variable, Transient Forcing: Conceptual Framework and Nitrate Case Study

    NASA Astrophysics Data System (ADS)

    Harter, T.; van der Schans, M. L.; Leijnse, A.

    2003-12-01

    We introduce a general stochastic concept of regional groundwater nonpoint source pollution in production wells or other groundwater discharge areas; present an efficient numerical procedure for its implementation; and validate the approach using a case study. Our principal hypothesis is that regional variability of and uncertainty about well pollution from nonpoint sources is primarily caused by the spatio-temporal variability of the nonpoint source strength (recharge rate and recharge pollutant concentration) and the variable spatial distribution of pumping wells, pumping rates, and other groundwater discharge relative to the location of the nonpoint sources. We describe a conceptual model of random space functions (RSFs) for nonpoint sources and wells. The resulting stochastic flow and transport equations are subject to random forcing in the nonpoint source and pumping boundary conditions (external variability). The stochastic forcing analysis yields a transient probability distribution function of water quality (water quality pdf) in a regional set of randomly distributed, discrete production wells and other groundwater discharge areas. We introduce a novel three-step numerical approach for the stochastic forcing analysis and apply the method to determine the 150-year (1910-2060) nitrate pdf for an irrigated, semi-arid region with a history of high groundwater nitrate. Comparison of the simulated nitrate pdfs with results from regional and domestic well water surveys in 1970, 1986 and 2001 shows that stochastic forcing indeed accounts for the observed temporal nitrate dynamics (mean concentration) and for 70% of the spatial variability observed in domestic well water nitrate in that region.

  7. Integrated watershed economic model for non-point source pollution management in Upper Big Walnut Creek Watershed, OH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Today, non-point source pollution (NPS) is one of the major sources of water quality impairments globally (UNEP, 2007). In the US, nutrient pollution is the leading cause of water quality issues in lakes and estuaries (USEPA, 2002). The maximum concentration of nutrients in streams is found to be in...

  8. Natural Wetlands Mediate Non-point Source Water Pollution From Irrigated Pastures

    NASA Astrophysics Data System (ADS)

    Knox, K.; Dahlgren, R. A.; Tate, K. W.

    2005-12-01

    Non-point source discharge from grazed pastures may be high in nutrients, sediment, and pathogens, three major contributors to water quality impairment in California. Intercepting pollution at its source and managing water quality within the landscape are essential to maintaining healthy downstream waters. We investigated the efficacy of flow-through wetlands interspersed throughout the agricultural landscape to reduce non-point source pollution of tailwater from cattle-grazed, irrigated pastures in the Sierra Nevada Foothills of California. Wetlands are known to positively impact water quality through ecological processes such as filtration, sedimentation, microbial transformations and plant uptake of nutrients. Influent and effluent water of small (0.25 ha), natural wetlands located downstream from flood irrigated pastures was analyzed for Escherichia coli, NO3-N, total N, total suspended solids (TSS), total P, and dissolved organic carbon (DOC) throughout two summer irrigation seasons (June to October). We compared reductions of sediment, nutrients and E. coli provided by a healthy, non-degraded wetland with reductions from flow through a channelized, degraded wetland. Large reductions in E. coli (>75%) and TSS (>50%) were observed in water exiting the healthy wetland while nutrient and DOC (~ 20%) concentrations were less affected by flow through the wetland. The channelized wetland provided smaller reductions in all constituents than did the non-degraded wetland. Results from this study demonstrate that small flow-through wetlands can improve water quality through the attenuation of E. coli and suspended sediments, and to a lesser degree DOC and nutrients.

  9. Atmospheric deposition of selected chemicals and their effect on nonpoint-source pollution in the Twin Cities Metropolitan Area, Minnesota

    USGS Publications Warehouse

    Brown, R.G.

    1984-01-01

    The atmospheric contribution to nonpoint-source-runoff pollution of nitrogen, in the form of nitrite-plus-nitrate, and lead was extremely high contributing as much as 84 percent of the runoff load. In contrast, phosphorus and chloride inputs were low averaging of 6 percent of the total runoff load. Future investigations of nonpoint-source pollution in runoff might include collection of data on atmospheric deposition of nitrite-plus-nitrate nitrogen and lead because of the importance of that source of these constituents in runoff.

  10. Point and non-point microbial source pollution: A case study of Delhi

    NASA Astrophysics Data System (ADS)

    Jamwal, Priyanka; Mittal, Atul K.; Mouchel, Jean-Marie

    The present study identifies major point and non-point sources of microbial pollution during dry and wet weather in Delhi watershed which is the first prerequisite for planning and management of water quality of the river Yamuna. Fecal coliforms (FC) and fecal streptococci (FS) levels were determined from two types of sources - point source (effluent from sewage treatment plants) and non-point source (stormwater runoff during dry and wet weather). FC and FS levels in the river Yamuna were also monitored, which is an ultimate sink for all microbial loads in Delhi watershed. Effluent from sewage treatment plants (STPs) employing different treatment technologies were evaluated. FC and FS levels greater than the effluent discharge standard (1000 MPN/100 ml) were observed in the effluents from all STPs except “oxidation pond Timarpur”. This study also involved field program for characterization of urban runoff from different land-uses. Results indicated that the microbial quality of urban runoff produced during wet weather from different land-uses was similar to that of raw sewage. Sewage overflows along with human and animal sources were responsible for high FC and FS levels in the runoff samples. Wet weather FC and FS levels in river Yamuna were higher as compared to the dry weather levels suggesting that dilution of the river water during wet weather does not affect its microbiological quality. Thus on the basis of this study it was found that urban runoff also contributes to the microbial quality of the river Yamuna.

  11. [Spatial discharge characteristics and total load control of non-point source pollutants based on the catchment scale].

    PubMed

    Wang, Xia-Hui; Lu, Jun; Zhang, Qing-Zhong; Wang, Bo; Yao, Rui-Hua; Zhang, Hui-Yuan; Huang, Feng

    2011-09-01

    Agricultural non-point source pollution is one of the major causes of water quality deterioration. Based on the analysis of the spatial discharge characteristics and intensity of major pollutants from the agricultural pollution source, the establishment of spatial management subzones for controlling agricultural non-point pollution and a design of a plan for total load control of pollutants from each subzone is an important way to improve the efficiency of control measures. In this paper the Four Lake basin in Hubei Province is adopted as the research case region and a systematic research of the control countermeasures of agricultural non-point pollution based on the catchment scale is carried out. The results shows that in the Four Lake basin, the COD, total nitrogen, total phosphorus and ammonia nitrogen load of the water environment are mainly caused by agricultural non-point pollution. These four kinds of non-point source pollutants respectively account for 67.6%, 82.2%, 84.7% and 50.9% of the total pollutant discharge amount in the basin. The analysis of the spatial discharge characteristics of non-point source pollutants in the Four Lake basin shows that the major contributor source regions of non-point source pollutant in the basin are the four counties, including Honghu, Jianli, Qianjiang and Shayang where the aquatic and livestock production are relatively developed. According to the spatial discharge characteristics of the pollutants and the evaluation of the discharge intensity of pollutants, the Four Lake basin is divided into three agricultural non-point pollution management subzones, which including Changhu upstream aquatic and livestock production pollution control subzone, Four-lake trunk canal rural non-point source pollution control subzone and Honghu aquatic production pollution control subzone. Specific pollution control measures are put forward for each subzone. With a comprehensive consideration of the water quality amelioration and the

  12. a Study on the Comprehensive Simulation of Nonpoint Source Pollution for Er-Hai Lake's Watershed in Dali of China

    NASA Astrophysics Data System (ADS)

    Yang, K.; Xu, Q. L.; Ye, L. Y.

    2012-07-01

    Er-hai Lake lies in state of Dali of Yunnan Province in China, which is so important to the local people that they revere her as the Mother Lake. Unfortunately, she is threatened by the more serious pollution of water. And from the water quality assessment of Er-hai Lake over the years, it is indicated that the major water pollution source come from nonpoint source pollution. The argument is that what has formed the nonpoint source pollution? As we known, the land use and cover change of watershed called LUCC is deemed as the major reason for Non-point pollution of water. However, what has made the land use and cover changes? It is another important question we should give an answer for water pollution. Many evidences have given that the change of LUCC is more due to the human activities in watershed, especially those for agriculture production. Thereby, there is a chain process for water pollution formation in Er-hai Lake Watershed, which could be described like this: Human activities (more in agriculture) have changed LUCC, and LUCC leads non-point source pollution. As a result, in this paper, those have been discussed according to the driving mechanism of nonpoint source water pollution in Er-hai Lake, which include three explorations. The first is how to build a ABM-LUCC model by using Repast and GIS technology, and the second is the method and implementation for hydrological and water quality model by using SWAT model and GIS, as well as Remote Sensing technology. And establishing a platform for comprehensively simulating the whole process of water pollution by integrating GIS, ABM-LUCC models and hydrological models is the last work for this study.

  13. 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.

  14. Vertical Variation of Nonpoint Source Pollutants in the Three Gorges Reservoir Region

    PubMed Central

    Shen, Zhenyao; Chen, Lei; Hong, Qian; Xie, Hui; Qiu, Jiali; Liu, Ruimin

    2013-01-01

    Nonpoint source (NPS) pollution is considered the main reason for water deterioration, but there has been no attempt to incorporate vertical variations of NPS pollution into watershed management, especially in mountainous areas. In this study, the vertical variations of pollutant yields were explored in the Three Gorges Reservoir Region (TGRR) and the relationships between topographic attributes and pollutant yields were established. Based on our results, the pollutant yields decreased significantly from low altitude to median altitude and leveled off rapidly from median altitude to high altitude, indicating logarithmic relationships between pollutant yields and altitudes. The pollutant yields peaked at an altitude of 200–500 m, where agricultural land and gentle slopes (0–8°) are concentrated. Unlike the horizontal distributions, these vertical variations were not always related to precipitation patterns but did vary obviously with land uses and slopes. This paper also indicates that altitude data and proportions of land use could be a reliable estimate of NPS yields at different altitudes, with significant implications for land use planning and watershed management. PMID:23951110

  15. An auto-adaptive optimization approach for targeting nonpoint source pollution control practices

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Wei, Guoyuan; Shen, Zhenyao

    2015-10-01

    To solve computationally intensive and technically complex control of nonpoint source pollution, the traditional genetic algorithm was modified into an auto-adaptive pattern, and a new framework was proposed by integrating this new algorithm with a watershed model and an economic module. Although conceptually simple and comprehensive, the proposed algorithm would search automatically for those Pareto-optimality solutions without a complex calibration of optimization parameters. The model was applied in a case study in a typical watershed of the Three Gorges Reservoir area, China. The results indicated that the evolutionary process of optimization was improved due to the incorporation of auto-adaptive parameters. In addition, the proposed algorithm outperformed the state-of-the-art existing algorithms in terms of convergence ability and computational efficiency. At the same cost level, solutions with greater pollutant reductions could be identified. From a scientific viewpoint, the proposed algorithm could be extended to other watersheds to provide cost-effective configurations of BMPs.

  16. Modeling Agricultural Nonpoint Source Pollution Using a Geographic Information System Approach

    NASA Astrophysics Data System (ADS)

    Emili, Lisa A.; Greene, Richard P.

    2013-01-01

    Agricultural non-point source (NPS) pollution, primarily sediment and nutrients, is the leading source of water-quality impacts to surface waters in North America. The overall goal of this study was to develop geographic information system (GIS) protocols to facilitate the spatial and temporal modeling of changes in soils, hydrology, and land-cover change at the watershed scale. In the first part of this article, we describe the use of GIS to spatially integrate watershed scale data on soil erodibility, land use, and runoff for the assessment of potential source areas within an intensively agricultural watershed. The agricultural non-point source pollution (AGNPS) model was used in the Muddy Creek, Ontario, watershed to evaluate the effectiveness of management strategies in decreasing sediment and nutrient [phosphorus (P)] pollution. This analysis was accompanied by the measurement of water-quality parameters (dissolved oxygen, pH, hardness, alkalinity, and turbidity) as well as sediment and P loadings to the creek. Practices aimed at increasing year-round soil cover would be most effective in decreasing sediment and P losses in this watershed. In the second part of this article, we describe a method for characterizing land-cover change in a dynamic urban fringe watershed. The GIS method we developed for the Blackberry Creek, Illinois, watershed will allow us to better account for temporal changes in land use, specifically corn and soybean cover, on an annual basis and to improve on the modeling of watershed processes shown for the Muddy Creek watershed. Our model can be used at different levels of planning with minimal data preprocessing, easily accessible data, and adjustable output scales.

  17. User's Guide for the Agricultural Non-Point Source (AGNPS) Pollution Model Data Generator

    USGS Publications Warehouse

    Finn, Michael P.; Scheidt, Douglas J.; Jaromack, Gregory M.

    2003-01-01

    BACKGROUND Throughout this user guide, we refer to datasets that we used in conjunction with developing of this software for supporting cartographic research and producing the datasets to conduct research. However, this software can be used with these datasets or with more 'generic' versions of data of the appropriate type. For example, throughout the guide, we refer to national land cover data (NLCD) and digital elevation model (DEM) data from the U.S. Geological Survey (USGS) at a 30-m resolution, but any digital terrain model or land cover data at any appropriate resolution will produce results. Another key point to keep in mind is to use a consistent data resolution for all the datasets per model run. The U.S. Department of Agriculture (USDA) developed the Agricultural Nonpoint Source (AGNPS) pollution model of watershed hydrology in response to the complex problem of managing nonpoint sources of pollution. AGNPS simulates the behavior of runoff, sediment, and nutrient transport from watersheds that have agriculture as their prime use. The model operates on a cell basis and is a distributed parameter, event-based model. The model requires 22 input parameters. Output parameters are grouped primarily by hydrology, sediment, and chemical output (Young and others, 1995.) Elevation, land cover, and soil are the base data from which to extract the 22 input parameters required by the AGNPS. For automatic parameter extraction, follow the general process described in this guide of extraction from the geospatial data through the AGNPS Data Generator to generate input parameters required by the pollution model (Finn and others, 2002.)

  18. Application of a constructed wetland for non-point source pollution control.

    PubMed

    Kao, C M; Wang, J Y; Lee, H Y; Wen, C K

    2001-01-01

    In Taiwan, non-point source (NPS) pollution is one of the major causes of impairment of surface waters. The main objective of this study was to evaluate the efficacy of using constructed wetlands on NPS pollutant removal and water quality improvements. A field-scale constructed wetland system was built inside the campus of National Sun Yat-Sen University (located in southern Taiwan) to remove (1) NPS pollutants due to the stormwater runoff, and (2) part of the untreated wastewater from school drains. The constructed wetland was 40 m (L) x 30 m (W) x 1 m (D), which received approximately 85 m3 per day of untreated wastewater from school drainage pipes. The plants grown on the wetland included floating (Pistia stratiotes L.) and emergent (Phragmites communis L.) species. One major storm event and baseline water quality samples were analyzed during the monitoring period. Analytical results indicate that the constructed wetland removed a significant amount of NPS pollutants and wastewater constituents. More than 88% of nitrogen, 81% of chemical oxygen demand (COD), 85% of heavy metals, and 60% of the total suspended solids (TSS) caused by the storm runoff were removed by the wetland system before discharging. Results from this study may be applied to the design of constructed wetlands for NPS pollution control and water quality improvement. PMID:11804154

  19. Reducing Nonpoint Source Pollution Through Collaboration: Policies and Programs Across the U.S. States

    NASA Astrophysics Data System (ADS)

    Hardy, Scott D.; Koontz, Tomas M.

    2008-03-01

    Nonpoint source (NPS) pollution has emerged as the largest threat to water quality in the United States, influencing policy makers and resource managers to direct more attention toward NPS prevention and remediation. In response, the United States Environmental Protection Agency (USEPA) spent more than 204 million in fiscal year (FY) 2006 on the Clean Water Act’s Section 319 program to combat NPS pollution, much of it on the development and implementation of watershed-based plans. State governments have also increasingly allocated financial and technical resources to collaborative watershed efforts within their own borders to fight NPS pollution. With increased collaboration among the federal government, states, and citizens to combat NPS pollution, more information is needed to understand how public resources are being used, by whom, and for what, and what policy changes might improve effectiveness. Analysis from a 50-state study suggests that, in addition to the average 35% of all Section 319 funds per state that are passed on to collaborative watershed groups, 35 states have provided financial assistance beyond Section 319 funding to support collaborative watershed initiatives. State programs frequently provide technical assistance and training, in addition to financial resources, to encourage collaborative partnerships. Such assistance is typically granted in exchange for requirements to generate a watershed action plan and/or follow a mutually agreed upon work plan to address NPS pollution. Program managers indicated a need for greater fiscal resources and flexibility to achieve water quality goals.

  20. Landscape planning for agricultural nonpoint source pollution reduction III: Assessing phosphorus and sediment reduction potential

    USGS Publications Warehouse

    Diebel, M.W.; Maxted, J.T.; Robertson, D.M.; Han, S.; Vander Zanden, M. J.

    2009-01-01

    Riparian buffers have the potential to improve stream water quality in agricultural landscapes. This potential may vary in response to landscape characteristics such as soils, topography, land use, and human activities, including legacies of historical land management. We built a predictive model to estimate the sediment and phosphorus load reduction that should be achievable following the implementation of riparian buffers; then we estimated load reduction potential for a set of 1598 watersheds (average 54 km2) in Wisconsin. Our results indicate that land cover is generally the most important driver of constituent loads in Wisconsin streams, but its influence varies among pollutants and according to the scale at which it is measured. Physiographic (drainage density) variation also influenced sediment and phosphorus loads. The effect of historical land use on present-day channel erosion and variation in soil texture are the most important sources of phosphorus and sediment that riparian buffers cannot attenuate. However, in most watersheds, a large proportion (approximately 70%) of these pollutants can be eliminated from streams with buffers. Cumulative frequency distributions of load reduction potential indicate that targeting pollution reduction in the highest 10% of Wisconsin watersheds would reduce total phosphorus and sediment loads in the entire state by approximately 20%. These results support our approach of geographically targeting nonpoint source pollution reduction at multiple scales, including the watershed scale. ?? 2008 Springer Science+Business Media, LLC.

  1. Nonpoint source pollution responses simulation for conversion cropland to forest in mountains by SWAT in China.

    PubMed

    Ouyang, Wei; Hao, Fang-Hua; Wang, Xue-Lei; Cheng, Hong-Guang

    2008-01-01

    Several environmental protection policies have been implemented to prevent soil erosion and nonpoint source (NPS) pollutions in China. After severe Yangtze River floods, the "conversion cropland to forest policy" (CCFP) was carried out throughout China, especially in the middle and upper reaches of Yangtze River. The research area of the current study is located in Bazhong City, Sichuan Province in Yangtze River watershed, where soil erosion and NPS pollution are serious concerns. Major NPS pollutants include nitrogen (N) and phosphorus (P). The objective of this study is to evaluate the long-term impact of implementation of the CCFP on stream flow, sediment yields, and the main NPS pollutant loading at watershed level. The Soil and Water Assessment Tool (SWAT) is a watershed environmental model and is applied here to simulate and quantify the impacts. Four scenarios are constructed representing different patterns of conversion from cropland to forest under various conditions set by the CCFP. Scenario A represented the baseline, i.e., the cropland and forest area conditions before the implementation of CCFP. Scenario B represents the condition under which all hillside cropland with slope larger than 25 degrees was converted into forest. In scenario C and D, hillside cropland with slope larger than 15 degrees and 7.5 degrees was substituted by forest, respectively. Under the various scenarios, the NPS pollution reduction due to CCFP implementation from 1996-2005 is estimated by SWAT. The results are presented as percentage change of water flow, sediment, organic N, and organic P at watershed level. Furthermore, a regression analysis is conducted between forest area ratio and ten years' average NPS load estimations, which confirmed the benefits of implementing CCFP in reducing nonpoint source pollution by increasing forest area in mountainous areas. The reduction of organic N and organic P is significant (decrease 42.1% and 62.7%, respectively) at watershed level. In

  2. Isotopic Tracers for Delineating Non-Point Source Pollutants in Surface Water

    SciTech Connect

    Davisson, M L

    2001-03-01

    This study tested whether isotope measurements of surface water and dissolved constituents in surface water could be used as tracers of non-point source pollution. Oxygen-18 was used as a water tracer, while carbon-14, carbon-13, and deuterium were tested as tracers of DOC. Carbon-14 and carbon-13 were also used as tracers of dissolved inorganic carbon, and chlorine-36 and uranium isotopes were tested as tracers of other dissolved salts. In addition, large databases of water quality measurements were assembled for the Missouri River at St. Louis and the Sacramento-San Joaquin Delta in California to enhance interpretive results of the isotope measurements. Much of the water quality data has been under-interpreted and provides a valuable resource to investigative research, for which this report exploits and integrates with the isotope measurements.

  3. Impacts of input parameter spatial aggregation on an agricultural nonpoint source pollution model

    NASA Astrophysics Data System (ADS)

    FitzHugh, T. W.; Mackay, D. S.

    2000-09-01

    The accuracy of agricultural nonpoint source pollution models depends in part on how well model input parameters describe the relevant characteristics of the watershed. The spatial extent of input parameter aggregation has previously been shown to have a substantial impact on model output. This study investigates this problem using the Soil and Water Assessment Tool (SWAT), a distributed-parameter agricultural nonpoint source pollution model. The primary question addressed here is: how does the size or number of subwatersheds used to partition the watershed affect model output, and what are the processes responsible for model behavior? SWAT was run on the Pheasant Branch watershed in Dane County, WI, using eight watershed delineations, each with a different number of subwatersheds. Model runs were conducted for the period 1990-1996. Streamflow and outlet sediment predictions were not seriously affected by changes in subwatershed size. The lack of change in outlet sediment is due to the transport-limited nature of the Pheasant Branch watershed and the stable transport capacity of the lower part of the channel network. This research identifies the importance of channel parameters in determining the behavior of SWAT's outlet sediment predictions. Sediment generation estimates do change substantially, dropping by 44% between the coarsest and the finest watershed delineations. This change is primarily due to the sensitivity of the runoff term in the Modified Universal Soil Loss Equation to the area of hydrologic response units (HRUs). This sensitivity likely occurs because SWAT was implemented in this study with a very detailed set of HRUs. In order to provide some insight on the scaling behavior of the model two indexes were derived using the mathematics of the model. The indexes predicted SWAT scaling behavior from the data inputs without a need for running the model. Such indexes could be useful for model users by providing a direct way to evaluate alternative models

  4. Introduction: Assessing non-point source pollution in the vadose zone with advanced information technologies

    NASA Astrophysics Data System (ADS)

    Corwin, Dennis L.; Loague, Keith; Ellsworth, Timothy R.

    The information age has ushered in a global awareness of complex environmental problems that do not respect political or physical boundaries: climatic change, ozone layer depletion, deforestation, desertification, and non-point source (NPS) pollution. Among these global environmental problems, NPS pollutants represent a perfect example of a complex multidisciplinary problem that exists over multiple scales with tremendous spatial and temporal complexity. To address the NPS problem, specific to the vadose zone, advanced information technologies must be applied in a spatial context. An integrated system of advanced information technologies (i.e., global positioning, geographic information system, geostatistics, remote sensing, solute transport modeling, neural networks, transfer functions, fuzzy logic, hierarchical theory, and uncertainty analysis) provides a framework from which real-time and/or simulated assessments of NPS pollution can be made. The ability to accurately assess present and future NPS-pollution impacts on ecosystems ranging from local to global scales provides a powerful tool for environmental stewardship and guiding future human activities.

  5. Evaluating agricultural nonpoint-source pollution programs in two Lake Erie tributaries.

    PubMed

    Forster, D Lynn; Rausch, Jonathan N

    2002-01-01

    During the past three decades, numerous government programs have encouraged Lake Erie basin farmers to adopt practices that reduce water pollution. The first section of this paper summarizes these state and federal government agricultural pollution abatement programs in watersheds of two prominent Lake Erie tributaries, the Maumee River and Sandusky River. Expenditures are summarized for each program, total expenditures in each county are estimated, and cost effectiveness of program expenditures (i.e., cost per metric ton of soil saved) are analyzed. Farmers received nearly $143 million as incentive payments to implement agricultural nonpoint source pollution abatement programs in the Maumee and Sandusky River watersheds from 1987 to 1997. About 95% of these funds was from federal sources. On average, these payments totaled about $7000 per farm or about $30 per farm acre (annualized equivalent of $2 per acre) within the watersheds. Our analysis raises questions about how efficiently these incentive payments were allocated. The majority of Agricultural Conservation Program (ACP) funds appear to have been spent on less cost-effective practices. Also, geographic areas with relatively low (high) soil erosion rates received relatively large (small) funding. PMID:11837427

  6. Contribution of base flow to nonpoint source pollution loads in an agricultural watershed

    USGS Publications Warehouse

    Schilling, K.E.; Wolter, C.F.

    2001-01-01

    Nonpoint source pollution of surface water from overland flow, drainage tiles, and ground water discharge is a major cause of water quality impairment in Iowa. Nonpoint source pollution from base flow ground water was estimated in the Walnut Creek watershed by measuring chemical loads of atrazine, nitrate, chloride, and sulfate at 18 tributary creeks and 19 tiles. Loads were measured during a stable base flow period at creeks and files that discharged into Walnut Creek between two stream gauges. Chemical concentrations of atrazine (< 0.1-12 ??g/L), nitrate (0.1 to 15 mg/L, and chloride (1.5 to 26 mg/L) in water were similar for creek and tile samples. Water draining predominantly agricultural row crop areas had much higher concentrations than water draining restored prairie areas. Three methods were used to estimate base flow discharge in the watershed: (1) Darcy flux; (2) watershed discharge budget; and (3) discharge-drainage area; each yielded similar results (31.2 L/s to 62.3 L/s). Base flow loads to the main channel were estimated by subtracting the loads from the upstream gauge; creeks and tiles, from the total load measured at the downstream gauge station. Base flow concentration for atrazine ranged from 0.15 to 0.29 ??g/L and sulfate concentration ranged from 32 to 64 mg/L, whereas concentrations for nitrate and chloride were negative (-1 to -4 mg/L). Calculated base flow concentrations of atrazine and sulfate appeared to be reasonable estimates, but negative concentrations of nitrate and chloride imply either loss of chemical mass in the stream from upstream to downstream sampling points or measurement error. Load data suggest little contribution from base flow pollutants to Walnut Creek water quality, with most of the pollutant load derived from major tributary creeks. Results from this study have implications for determining total maximum daily loads in agricultural watersheds where contributions from point sources (creeks and tiles) can he used to

  7. Relationships Between Landscape Characteristics and Nonpoint Source Pollution Inputs to Coastal Estuaries.

    PubMed

    BASNYAT; TEETER; FLYNN; LOCKABY

    1999-05-01

    / Land-use activities affect water quality by altering sediment, chemical loads, and watershed hydrology. Some land uses may contribute to the maintenance of water quality due to a biogeochemical transformation process. These land-use/land-cover types can serve as nutrient detention zones or as nutrient transformation zones as dissolved or suspended nutrients or sediments move downstream. Despite research on the effects of individual land-use/land-cover types, very little has been done to analyze the joint contributions of multiple land-use activities. This paper examines a methodology to assess the relationships between land-use complex and nitrate and sediment concentrations [nonpoint source (NPS) pollutants] in streams. In this process, selected basins of the Fish River, Alabama, USA, were delineated, land-use/land-cover types were classified, and contributing zones were identified using geographic information system (GIS) and remote sensing (RS) analysis tools. Water samples collected from these basins were analyzed for selected chemical and physical properties. Based on the contributions of the NPS pollutants, a linkage model was developed. This linkage model relates land use/land cover with the pollution levels in the stream. Linkage models were constructed and evaluated at three different scales: (1) the basin scale; (2) the contributing-zone scale; and (3) the stream-buffer/riparian-zone scale. The contributing-zones linkage model suggests that forests act as a transformation zone, and as the proportion of forest inside a contributing zone increases (or agricultural land decreases), nitrate levels downstream will decrease. Residential/urban/built-up areas were identified as the strongest contributors of nitrate in the contributing-zones model and active agriculture was identified as the second largest contributor. The regression results for the streambank land-use/land-cover model (stream-buffer/riparian-zone scale) suggest that water quality is highest

  8. Denitrification controls in urban riparian soils: implications for reducing urban nonpoint source nitrogen pollution.

    PubMed

    Li, Yangjie; Chen, Zhenlou; Lou, Huanjie; Wang, Dongqi; Deng, Huanguang; Wang, Chu

    2014-09-01

    The purpose of this research was to thoroughly analyze the influences of environmental factors on denitrification processes in urban riparian soils. Besides, the study was also carried out to identify whether the denitrification processes in urban riparian soils could control nonpoint source nitrogen pollution in urban areas. The denitrification rates (DR) over 1 year were measured using an acetylene inhibition technique during the incubation of intact soil cores from six urban riparian sites, which could be divided into three types according to their vegetation. The soil samples were analyzed to determine the soil organic carbon (SOC), soil total nitrogen (STN), C/N ratio, extractable NO3 (-)-N and NH4 (+)-N, pH value, soil water content (SWC), and the soil nitrification potential to evaluate which of these factors determined the final outcome of denitrification. A nitrate amendment experiment further indicated that the riparian DR was responsive to added nitrate. Although the DRs were very low (0.099 ~ 33.23 ng N2O-N g(-1) h(-1)) due to the small amount of nitrogen moving into the urban riparian zone, the spatial and temporal patterns of denitrification differed significantly. The extractable NO3 (-)-N proved to be the dominant factor influencing the spatial distribution of denitrification, whereas the soil temperature was a determinant of the seasonal DR variation. The six riparian sites could also be divided into two types (a nitrate-abundant and a nitrate-stressed riparian system) according to the soil NO3 (-)-N concentration. The DR in nitrate-abundant riparian systems was significantly higher than that in the nitrate-stressed riparian systems. The DR in riparian zones that were covered with bushes and had adjacent cropland was higher than in grass-covered riparian sites. Furthermore, the riparian DR decreased with soil depth, which was mainly attributed to the concentrated nitrate in surface soils. The DR was not associated with the SOC, STN, C/N ratio, and

  9. An auto-adaptive optimization approach for targeting nonpoint source pollution control practices

    PubMed Central

    Chen, Lei; Wei, Guoyuan; Shen, Zhenyao

    2015-01-01

    To solve computationally intensive and technically complex control of nonpoint source pollution, the traditional genetic algorithm was modified into an auto-adaptive pattern, and a new framework was proposed by integrating this new algorithm with a watershed model and an economic module. Although conceptually simple and comprehensive, the proposed algorithm would search automatically for those Pareto-optimality solutions without a complex calibration of optimization parameters. The model was applied in a case study in a typical watershed of the Three Gorges Reservoir area, China. The results indicated that the evolutionary process of optimization was improved due to the incorporation of auto-adaptive parameters. In addition, the proposed algorithm outperformed the state-of-the-art existing algorithms in terms of convergence ability and computational efficiency. At the same cost level, solutions with greater pollutant reductions could be identified. From a scientific viewpoint, the proposed algorithm could be extended to other watersheds to provide cost-effective configurations of BMPs. PMID:26487474

  10. Multi-Scale Monitoring and Assessment of Nonpoint Source Pollution in Groundwater

    NASA Astrophysics Data System (ADS)

    Harter, T.; Vanderschans, M.; Leijnse, A.; Mathews, M. C.; Meyer, R. D.

    2003-04-01

    The California dairy industry produces 20% of US milk and is the largest animal industry in the state. Many of the dairy facilities are located in low-relief valleys and basins with vulnerable groundwater resources. The continued influx of dairies into California's Central Valley has raised critical questions regarding their environmental performance, in particular with respect to groundwater quality impacts. While animal farming systems are considered among the leading sources of groundwater nitrate,little is known about the actual impact of dairy farming practices on groundwater quality in the extensive alluvial aquifers underlying the Central Valley. With our work we attempt to characterize and assess shallow groundwater underneath dairies in a relatively vulnerable hydrogeologic region and to discern the impact from various individual sources and management practices within dairies. An extensive shallow groundwater monitoring network was installed on five representative dairy operations in the northeastern San Joaquin Valley, California. The monitoring network spans all dairy management units: manure water lagoons, corrals, storage areas, and manure treated forage fields under various management practices. We recently also surveyed production well water quality. Water quality is found to be highly variable, both in time and space. We propose that a meaningful interpretation of these (nonpoint source pollution) data is only possible by explicitly considering the various scales affiliated with groundwater measurement, pollution source management, regulatory control, and beneficial use. Using statistical analysis and innovative modeling tools, we provide an interpretation of the observed data that is meaningful at the field scale (the scale unit of management decisions), the farm scale (considered to be a regulatory and planning unit), and the regional scale (considered to be a planning unit).

  11. Temporal-spatial distribution of non-point source pollution in a drinking water source reservoir watershed based on SWAT

    NASA Astrophysics Data System (ADS)

    Wang, M.; Cheng, W.; Yu, B.-S.; Fang, Y.

    2015-05-01

    The conservation of drinking water source reservoirs has a close relationship between regional economic development and people's livelihood. Research on the non-point pollution characteristics in its watershed is crucial for reservoir security. Tang Pu Reservoir watershed was selected as the study area. The non-point pollution model of Tang Pu Reservoir was established based on the SWAT (Soil and Water Assessment Tool) model. The model was adjusted to analyse the temporal-spatial distribution patterns of total nitrogen (TN) and total phosphorus (TP). The results showed that the loss of TN and TP in the reservoir watershed were related to precipitation in flood season. And the annual changes showed an "M" shape. It was found that the contribution of loss of TN and TP accounted for 84.5% and 85.3% in high flow years, and for 70.3% and 69.7% in low flow years, respectively. The contributions in normal flow years were 62.9% and 63.3%, respectively. The TN and TP mainly arise from Wangtan town, Gulai town, and Wangyuan town, etc. In addition, it was found that the source of TN and TP showed consistency in space.

  12. Search for the northwest passage: the assignation of NSP (non-point source pollution) rights in nutrient trading programs.

    PubMed

    Collentine, D

    2002-01-01

    The search for solutions to the problem of non-point source pollution (NSP) includes alternatives based on theories associated with the use of tradable pollution permits. Tradable permit programs have received significant support as a promising policy for the reduction of effluent discharges but programs in practice have not been regarded as successful. The lack of success is ascribed to the design of the programs. However, this may be a design problem which is insurmountable due to the nature of the NSP problem. Tradable permit solutions are based on an assumption that the assignation of quantifiable rights to both point and nonpoint sources, based on some predetermined ambient water quality measure, is possible. The conclusion here is that there are significant features particular to NSP that hinder the introduction of rights and significantly decrease the utility of tradable permit solutions. PMID:12079107

  13. Stochastic modeling of the rainfall-runoff process for nonpoint source pollutant load estimation

    SciTech Connect

    Dickey, R.O.

    1989-01-01

    A stochastic simulation methodology was developed for the rainfall runoff process to assist in the assessment of nonpoint source pollutant loads, particularly for ungaged watersheds where there is a scarcity or complete lack of historical data. The methodology was developed based on simulating individual rainfall-runoff events. A simulation model employed a rainfall simulator to stochastically generate rainfall event characteristics for input into basin hydrologic transformation functions which then predicted the corresponding runoff hydrograph characteristics. Also addressed was the impact of limited data availability on the ability to model the rainfall-runoff process. An evaluation was conducted of the degree to which committing valuable resources to expand the data base would provide measurable improvement in model results. Specifically, the probability of achieving certain levels of accuracy with the simulation model was statistically assessed as a function of the number of observed rainfall-runoff events used for model development. The probability of monitoring various numbers of rainfall-runoff events in specified time intervals was also established as an aid for planning field monitoring studies. The simulation methodology was applied to a study watershed in the Lake Ray Hubbard reservoir drainage basin near Dallas, Texas. Regional rainfall characteristics were established using historical hourly data from the Federal Aviation Administration rain gage at Love Field Airport in Dallas, Texas. Hourly rainfall data were resolved into individual rainfall events and probability density functions were identified for event volume, time between events, and event duration.

  14. Evaluating the impacts of soil data on hydrological and nonpoint source pollution prediction.

    PubMed

    Chen, Lei; Wang, Guobo; Zhong, Yucen; Shen, Zhenyao

    2016-09-01

    Soil data are one key input for most hydrological and nonpoint source (H/NPS) models, and quantifying the error transmission from soil data to H/NPS predictions is of great importance. In this study, two typical soil datasets were compared using the Soil and Water Assessment Tool (SWAT) in a typical mountainous watershed, the Three Gorges Reservoir Region, China. Besides, the effects of soil data resolution were evaluated, and the error transmission from soil data to watershed management strategy was assessed. The results indicate that model outputs are not sensitive to changes of soil data resolution but the choice of soil data greatly impacts the application of watershed models, in terms of the goodness-of-fit indicator, predicted data and related uncertainty. This soil data-induced error would be inevitably magnified from the flow simulation to the NPS prediction stage. This study could indicate that the choice of soil data will lead to significant differences in management schemes for specific pollution periods. These results provide information on the impacts of soil data on the functionality of watershed models and valuable information for the appropriateness of each soil database. PMID:27135563

  15. A comprehensive evaluation of input data-induced uncertainty in nonpoint source pollution modeling

    NASA Astrophysics Data System (ADS)

    Chen, L.; Gong, Y.; Shen, Z.

    2015-11-01

    Watershed models have been used extensively for quantifying nonpoint source (NPS) pollution, but few studies have been conducted on the error-transitivity from different input data sets to NPS modeling. In this paper, the effects of four input data, including rainfall, digital elevation models (DEMs), land use maps, and the amount of fertilizer, on NPS simulation were quantified and compared. A systematic input-induced uncertainty was investigated using watershed model for phosphorus load prediction. Based on the results, the rain gauge density resulted in the largest model uncertainty, followed by DEMs, whereas land use and fertilizer amount exhibited limited impacts. The mean coefficient of variation for errors in single rain gauges-, multiple gauges-, ASTER GDEM-, NFGIS DEM-, land use-, and fertilizer amount information was 0.390, 0.274, 0.186, 0.073, 0.033 and 0.005, respectively. The use of specific input information, such as key gauges, is also highlighted to achieve the required model accuracy. In this sense, these results provide valuable information to other model-based studies for the control of prediction uncertainty.

  16. New Antimicrobially Amended Media for Improved Nonpoint Source Bacterial Pollution Treatment.

    PubMed

    Schifman, Laura A; Kasaraneni, Varun K; Sullivan, Ryan K; Oyanedel-Craver, Vinka; Boving, Thomas B

    2015-12-15

    Nonpoint source pollution (NPS) such as stormwater runoff may introduce high loads of bacteria, impairing surface water bodies. The existing filter materials in stormwater best management practices (BMP) are typically not designed to inactivate bacteria. Herein, novel filtration media were extensively tested for microbial load reduction in stormwater runoff. Red cedar wood chips (RC) were amended with different loadings of either 3-(trihydroxysilyl) propyldimethyloctadecyl ammonium chloride (TPA) or silver nanoparticles (AgNP). Under batch conditions at 25 °C, log10 removal values (LRV) up to 3.71 ± 0.38 (mean ± standard error) for TPA-RC and 2.25 ± 1.00 for AgNP-RC were achieved for Escherichia coli (E. coli), whereas unmodified RC achieved less than 0.5 LRV. Similar trends were observed at 17.5 °C, however at low temperature (10 °C) no statistically significant difference in E. coli inactivation between modified and unmodified RC was detected. Inactivation kinetic studies show that TPA-RC has higher inactivation rate constants compared to AgNP-RC. Under dynamic flow conditions a mass balance approach indicates that even after remobilization up to 99.8% of E. coli removal using 9 mg/g TPA-RC compared to 64.8% for unmodified RC. This study demonstrates that RC wood chips amended with antimicrobial compounds show promising applications as filtration material for the reduction of microbiological contamination load in stormwater runoff. PMID:26562065

  17. Assessing the effects of non-point source pollution on American Samoa's coral reef communities.

    PubMed

    Houk, Peter; Didonato, Guy; Iguel, John; Van Woesik, Robert

    2005-08-01

    Surveys were completed on Tutuila Island, American Samoa, to characterize reef development and assess the impacts of non-point source pollution on adjacent coral reefs at six sites. Multivariate analyses of benthic and coral community data found similar modern reef development at three locations; Aoa, Alofau, and Leone. These sites are situated in isolated bays with gentle sloping foundations. Aoa reefs had the highest estimates of crustose coralline algae cover and coral species richness, while Leone and Alofau showed high abundances of macroalgae and Porites corals. Aoa has the largest reef flat between watershed discharge and the reef slope, and the lowest human population density. Masefau and Fagaalu have a different geomorphology consisting of cemented staghorn coral fragments and steep slopes, however, benthic and coral communities were not similar. Benthic data suggest Fagaalu is heavily impacted compared with all other sites. Reef communities were assessed as bio-criteria indicators for waterbody health, using the EPA aquatic life use support designations of (1) fully supportive, (2) partially supportive, and (3) non-supportive for aquatic life. All sites resulted in a partially supportive ranking except Fagaalu, which was non-supportive. The results of this rapid assessment based upon relative benthic community measures are less desirable than long-term dataset analyses from monitoring programs, however it fills an important role for regulatory agencies required to report annual waterbody assessments. Future monitoring sites should be established to increase the number of replicates within each geological and physical setting to allow for meaningful comparisons along a gradient of hypothesized pollution levels. PMID:16418902

  18. 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

  19. Evaluation of a non-point source pollution model, AnnAGNPS, in a tropical watershed

    USGS Publications Warehouse

    Polyakov, V.; Fares, A.; Kubo, D.; Jacobi, J.; Smith, C.

    2007-01-01

    Impaired water quality caused by human activity and the spread of invasive plant and animal species has been identified as a major factor of degradation of coastal ecosystems in the tropics. The main goal of this study was to evaluate the performance of AnnAGNPS (Annualized Non-Point Source Pollution Model), in simulating runoff and soil erosion in a 48 km2 watershed located on the Island of Kauai, Hawaii. The model was calibrated and validated using 2 years of observed stream flow and sediment load data. Alternative scenarios of spatial rainfall distribution and canopy interception were evaluated. Monthly runoff volumes predicted by AnnAGNPS compared well with the measured data (R2 = 0.90, P < 0.05); however, up to 60% difference between the actual and simulated runoff were observed during the driest months (May and July). Prediction of daily runoff was less accurate (R2 = 0.55, P < 0.05). Predicted and observed sediment yield on a daily basis was poorly correlated (R2 = 0.5, P < 0.05). For the events of small magnitude, the model generally overestimated sediment yield, while the opposite was true for larger events. Total monthly sediment yield varied within 50% of the observed values, except for May 2004. Among the input parameters the model was most sensitive to the values of ground residue cover and canopy cover. It was found that approximately one third of the watershed area had low sediment yield (0-1 t ha-1 y-1), and presented limited erosion threat. However, 5% of the area had sediment yields in excess of 5 t ha-1 y-1. Overall, the model performed reasonably well, and it can be used as a management tool on tropical watersheds to estimate and compare sediment loads, and identify "hot spots" on the landscape. ?? 2007 Elsevier Ltd. All rights reserved.

  20. [Empirical study on non-point sources pollution based on landscape pattern & ecological processes theory: a case of soil water loss on the Loess Plateau in China].

    PubMed

    Suo, An-ning; Wang, Tian-ming; Wang, Hui; Yu, Bo; Ge, Jian-ping

    2006-12-01

    Non-point sources pollution is one of main pollution modes which pollutes the earth surface environment. Aimed at soil water loss (a typical non-point sources pollution problem) on the Losses Plateau in China, the paper applied a landscape patternevaluation method to twelve watersheds of Jinghe River Basin on the Loess Plateau by means of location-weighted landscape contrast index(LCI) and landscape slope index(LSI). The result showed that LSI of farm land, low density grass land, forest land and LCI responded significantly to soil erosion modulus and responded to depth of runoff, while the relationship between these landscape index and runoff variation index and erosion variation index were not statistically significant. This tell us LSI and LWLCI are good indicators of soil water loss and thus have big potential in non-point source pollution risk evaluation. PMID:17304833

  1. The precipitation driven correlation based mapping method (PCM) for identifying the critical source areas of non-point source pollution

    NASA Astrophysics Data System (ADS)

    Huang, Jinhui Jeanne; Lin, Xiaojuan; Wang, Jianhua; Wang, Hao

    2015-05-01

    Critical source areas (CSAs) are the areas that are relatively more erosion-prone and contribute significantly more pollutants per unit area. They have been widely recognized as optimal locations for the control of non-point source (NPS) pollution. Modeling approach has been frequently used to identify the CSAs of NPS pollution on a basin scale. In previous studies, CSAs were identified based on the simulated average annual nutrient yields for the simulation period at the levels of sub-basin or hydrologic response unit (HRU). However, this method did not consider the impact of uneven spatial distribution of precipitation, which is considered to be the driven force of NPS pollution. In many cases, due to limited length of qualified monitoring data collected, the simulation period may not cover a full spectrum of the precipitation characteristics so that some potential CSAs may be missed. In the present study, the precipitation driven correlation based mapping method (PCM) was proposed, which can reduce the impact of uncertain spatial-temporal distribution of precipitation and identify the CSAs of NPS pollution with a better coverage. This method was applied to the Zhang River Basin, a watershed in North China that occupies an area of 18,072 km2. The SWAT (Soil and Water Assessment Tool) was used for simulation purposes. By using PCM, the maps of CSAs for controlling total nitrogen (TN) and total phosphorus (TP) were produced. This study has found that the monthly precipitation is highly correlated with the TN and TP yields. It was observed that TN yields have slightly higher correlation value with the precipitation than TP yields. Hence, the precipitation has more impacts on TN yields than TP yields. The impact is more substantial in urban areas than other areas.

  2. The impact of information on behavior under an ambient-based policy for regulating nonpoint source pollution

    NASA Astrophysics Data System (ADS)

    Miao, Haoran; Fooks, Jacob R.; Guilfoos, Todd; Messer, Kent D.; Pradhanang, Soni M.; Suter, Jordan F.; Trandafir, Simona; Uchida, Emi

    2016-05-01

    Stemming from Segerson [1988], literature on nonpoint source pollution shows that ambient-based regulatory policies can induce polluters in a common watershed to comply with an exogenously determined pollution standard. This study uses laboratory economic experiments in a spatially heterogeneous setting to test the effectiveness of an ambient tax/subsidy policy in a setting with realistic in-stream nutrient transport dynamics when varying levels of sensor information on ambient pollution are available to the agents and the regulator. We find that increasing the frequency of ambient monitoring improves the spatial allocation of emissions reductions. In particular, with more frequent monitoring, the ambient-based policy induces firms further from the monitoring point to reduce emissions significantly more than downstream firms. Overall, the results suggest that enhanced temporal resolution of monitoring leads to efficiency gains.

  3. Soil erosion and non-point source pollution impacts assessment with the aid of multi-temporal remote sensing images.

    PubMed

    Ning, Shu-Kuang; Chang, Ni-Bin; Jeng, Kai-Yu; Tseng, Yi-Hsing

    2006-04-01

    Soil erosion associated with non-point source pollution is viewed as a process of land degradation in many terrestrial environments. Careful monitoring and assessment of land use variations with different temporal and spatial scales would reveal a fluctuating interface, punctuated by changes in rainfall and runoff, movement of people, perturbation from environmental disasters, and shifts in agricultural activities and cropping patterns. The use of multi-temporal remote sensing images in support of environmental modeling analysis in a geographic information system (GIS) environment leading to identification of a variety of long-term interactions between land, resources, and the built environment has been a highly promising approach in recent years. This paper started with a series of supervised land use classifications, using SPOT satellite imagery as a means, in the Kao-Ping River Basin, South Taiwan. Then, it was designed to differentiate the variations of eight land use patterns in the past decade, including orchard, farmland, sugarcane field, forest, grassland, barren, community, and water body. Final accuracy was confirmed based on interpretation of available aerial photographs and global positioning system (GPS) measurements. Finally, a numerical simulation model (General Watershed Loading Function, GWLF) was used to relate soil erosion to non-point source pollution impacts in the coupled land and river water systems. Research findings indicate that while the decadal increase in orchards poses a significant threat to water quality, the continual decrease in forested land exhibits a potential impact on water quality management. Non-point source pollution, contributing to part of the downstream water quality deterioration of the Kao-Ping River system in the last decade, has resulted in an irreversible impact on land integrity from a long-term perspective. PMID:16182435

  4. 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.

  5. Modeling non-point source pollutants in the vadose zone: Back to the basics

    NASA Astrophysics Data System (ADS)

    Corwin, Dennis L.; Letey, John, Jr.; Carrillo, Marcia L. K.

    More than ever before in the history of scientific investigation, modeling is viewed as a fundamental component of the scientific method because of the relatively recent development of the computer. No longer must the scientific investigator be confined to artificially isolated studies of individual processes that can lead to oversimplified and sometimes erroneous conceptions of larger phenomena. Computer models now enable scientists to attack problems related to open systems such as climatic change, and the assessment of environmental impacts, where the whole of the interactive processes are greater than the sum of their isolated components. Environmental assessment involves the determination of change of some constituent over time. This change can be measured in real time or predicted with a model. The advantage of prediction, like preventative medicine, is that it can be used to alter the occurrence of potentially detrimental conditions before they are manifest. The much greater efficiency of preventative, rather than remedial, efforts strongly justifies the need for an ability to accurately model environmental contaminants such as non-point source (NPS) pollutants. However, the environmental modeling advances that have accompanied computer technological development are a mixed blessing. Where once we had a plethora of discordant data without a holistic theory, now the pendulum has swung so that we suffer from a growing stockpile of models of which a significant number have never been confirmed or even attempts made to confirm them. Modeling has become an end in itself rather than a means because of limited research funding, the high cost of field studies, limitations in time and patience, difficulty in cooperative research and pressure to publish papers as quickly as possible. Modeling and experimentation should be ongoing processes that reciprocally enhance one another with sound, comprehensive experiments serving as the building blocks of models and models

  6. Predicting the impacts of climate change on nonpoint source pollutant loads from agricultural small watershed using artificial neural network.

    PubMed

    Lee, Eunjeong; Seong, Chounghyun; Hakkwan, Kim; Park, Seungwoo; Kang, Moonseong

    2010-01-01

    This study described the development and validation of an artificial neural network (ANN) for the purpose of analyzing the effects of climate change on nonpoint source (NPS) pollutant loads from agricultural small watershed. The runoff discharge was estimated using ANN algorithm. The performance of ANN modelwas examined using observed data from s tudy watershed. The simulationresults agreed well with observed values during calibration and validation periods. NPS pollutant loads were calculated from load-discharge relationship driven by long-term monitoring data. LARS-WG (Long Ashton Research Station-Weather Generator) model was used to generate rainfall data. The calibrated ANN model and load-discharge relationship with the generated data from LARS-WGwere applied to analyze the effects of climate change on NPS pollutant loads from the agricultural small watershed. The results showed that the ANN model provided valuable approach i n estimating future runof f discharge, and the NPS pollutantloads. PMID:20923094

  7. Study of the distribution of non-point source pollution in the watershed of the Miyun Reservoir, Beijing, China.

    PubMed

    Wang, X; Li, T; Xu, A; He, W

    2001-01-01

    Nitrogen and phosphorus are major nutrients to cause eutrophication to degrade the water quality of the Miyun Reservoir, a very important drinking water source of Beijing in China. These are mainly from non-point sources. The watershed in Miyun County is selected as the study region with a total area of 1400 km2. Four typical monitoring catchments and two experimental units were used to monitor the precipitation, runoff, sediment yield and pollutant loading related to various land uses in the meantime. The results show that the total nutrient loss amount of TN and TP is 898.07 t/a, and 40.70 t/a, respectively, in which nutrient N and P carried by runoff is 91.3% and 77.3%, respectively. There is relatively heavier soil erosion at the northern mountain area whereas the main nutrient loss occurs near the northeast rim of the reservoir. Different land uses influence the loss of non-point source pollutants. The amount of nutrient loss from agricultural land per unit is the highest, nutrient loss from forestry is the second highest and that from grassland is the lowest. However, due to the variability of land use areas, agricultural land contributes the greatest amount of TP and forestry lands the greatest amount of TN. PMID:11724492

  8. Simulation of spatial and temporal distributions of non-point source pollution load in the Three Gorges Reservoir Region.

    PubMed

    Shen, Zhenyao; Qiu, Jiali; Hong, Qian; Chen, Lei

    2014-09-15

    Non-point source (NPS) pollution has become the largest threat to water quality in recent years. Major pollutants, particularly from agricultural activities, which include nitrogen, phosphorus and sediment that have been released into aquatic environments, have caused a range of problems in the Three Gorges Reservoir Region (TGRR), China. It is necessary to identify the spatial and temporal distributions of NPS pollutants and the highly polluted areas for the purpose of watershed management. In this study, the NPS pollutant load was simulated using the Soil and Water Assessment Tool (SWAT) and the small-scale watershed extended method (SWEM). The simulation results for four typical small catchments were extended to the entire watershed leading to estimates of the NPS load from 2001 to 2009. The results demonstrated that the NPS pollution load in the western area was the highest and that agricultural land was the primary pollutant source. The similar annual variation trends of runoff and sediment loads demonstrated that the sediment load was closely related to runoff. The loads of total nitrogen (TN) and total phosphorus (TP) were relatively stable from 2001 to 2007, except for high loads in 2006. The increase in pollution source strength was an important reason for the significant upward trend of TN and TP loads from 2008 to 2009. The rainfall from April to October contributed to the largest amount of runoff, sediment and nutrient loads for the year. The NPS load intensities in each sub-basin reveal large variations in the spatial distribution of different pollutants. It was shown that the temporal and spatial distributions of pollutant loads were positively correlated with the annual rainfall amounts and with human activities. Furthermore, this finding illustrates that conservation practices and nutrient management should be implemented in specific sites during special periods for the purpose of NPS pollution control in the TGRR. PMID:24946028

  9. A GIS-based study on non-point source pollutant distribution around Miyun Reservoir Watershed, Beijing, China

    NASA Astrophysics Data System (ADS)

    Wang, X.; wang, y; cai, x; wang, x

    2001-12-01

    Nitrogen and phosphorus, coming mainly from non-point sources (NPS), are major nutrients to cause eutrophication to degrade water quality of Miyun Reservoir, the only one surface drinking water source of Beijing, China. The spatial nature of the NPS pollution problem necessitates the use of a geographic information system (GIS) to manipulate, retrieve, and display the large volumes of spatial data. Based on the relevant data which range from meteorological and hydrological data to land use, fertilizer and pesticide usage, and even livestock raising information, the database of NPS of Shixia Catchment in Miyun Reservoir watershed were established. Using GIS, abstracting attribute data, digitizing, editing, coordinate transferring and generating the digital elevation model (DEM) could be finished. A total of four land use scenarios were modeled to evaluate various land management strategies on sediment and nutrient loading from catchment. The results suggest that high nutrient loads are associated with village, which has unsuitable livestock raising. Different land use influences intensively the loss of pollutants, especially slope tilling in agricultural land. The amount of nutrient loss from the agricultural land per unit is the highest, that from forestry is the secondary and that from grassland is the lowest. However, due to the variability of land use areas, agricultural land contributes the greatest effort to TP and forestry lands to TN. The loss amount of pollutant in flood season is nearly 60% of annual loss amount. The amount of nutrient loss from hill areas is larger than that from mountain areas. Pattern of non-point source pollution in Miyun County is showed that near the north and east boundary of the Reservoir is the heaviest area. It is indicated that nutrient loss is correlated with people density, fertilizer usage and soil erosion.

  10. Assessment of the Impacts of Land Use Changes on Nonpoint Source Pollution Inputs Upstream of the Three Gorges Reservoir

    PubMed Central

    Yang, Huicai; Yang, Yan; Xue, Baolin; Wu, Binbin

    2014-01-01

    In recent years, land use upstream of the Three Gorges Reservoir (TGR) has changed significantly because of the TGR project. In this study, the Soil and Water Assessment Tool (SWAT) model was examined for its ability to assess relationships between land use changes and nonpoint pollutant indexes upstream of the TGR. Results indicated that the SWAT model, calibrated with the adjusted parameters, could successfully reproduce the nonpoint indexes at the water quality monitoring sites in the two rivers. The different land use change types were shown to be sensitive to nonpoint pollutants in the study area. The land use change type from upland to water was the strongest influence on changes in total nitrogen and total phosphorus. An empirical regression equation between nonpoint indexes and different land use change types was developed for the study area by partial least squares regression (PLSR) as follows: Y = b0 + ∑i=1mbiXi. This regression equation was useful for evaluating the influence of land use change types on changes in nonpoint pollutants over a long time period. The results from this study may be useful for the TGR management and may help to reduce nonpoint pollutant loads into downstream water bodies. PMID:24977205

  11. Assessment of the relationship between rural non-point source pollution and economic development in the Three Gorges Reservoir Area.

    PubMed

    Zhang, Tong; Ni, Jiupai; Xie, Deti

    2016-04-01

    This study investigates the relationship between rural non-point source (NPS) pollution and economic development in the Three Gorges Reservoir Area (TGRA) by using the Environmental Kuznets Curve (EKC) hypothesis for the first time. Five types of pollution indicators, namely, fertilizer input density (FD), pesticide input density (PD), agricultural film input density (AD), grain residues impact (GI), and livestock manure impact (MI), were selected as rural NPS pollutant variables. Rural net income per capita was used as the indicator of economic development. Pollution load was generated by agricultural inputs (consumption of fertilizer, pesticide, and agricultural film) and economic growth with invert U-shaped features. The predicted turning points for FD, PD, and AD were at rural net income per capita levels of 6167.64, 6205.02, and 4955.29 CNY, respectively, which were all surpassed. However, the features between agricultural waste outputs (grain residues and livestock manure) and economic growth were inconsistent with the EKC hypothesis, which reflected the current trends of agricultural economic structure in the TGRA. Given that several other factors aside from economic development level could influence the pollutant generation in rural NPS, a further examination with long-run data support should be performed to understand the relationship between rural NPS pollution and income level. PMID:26936476

  12. Severe situation of rural nonpoint source pollution and efficient utilization of agricultural wastes in the Three Gorges Reservoir Area.

    PubMed

    Zhang, Tong; Ni, Jiupai; Xie, Deti

    2015-11-01

    Rural nonpoint source (NPS) pollution caused by agricultural wastes has become increasingly serious in the Three Gorges Reservoir Area (TGRA), significantly affecting the reservoir water quality. The grim situation of rural NPS pollution in the TGRA indicated that agrochemicals (chemical fertilizer and pesticide) were currently the highest contributor of rural NPS pollution (50.38%). The harmless disposal rates of livestock excrement, crop straws, rural domestic refuse, and sewage also cause severe water pollution. More importantly, the backward agricultural economy and the poor environmental awareness of farmers in the hinterland of the TGRA contribute to high levels of rural NPS pollution. Over the past decade, researchers and the local people have carried out various successful studies and practices to realize the effective control of rural NPS pollution by efficiently utilizing agricultural wastes in the TGRA, including agricultural waste biogas-oriented utilization, crop straw gasification, decentralized land treatment of livestock excrement technology, and crop straw modification. These technologies have greatly increased the renewable resource utilization of agricultural wastes and improved water quality and ecological environment in the TGRA. PMID:26392092

  13. Modelling of point and non-point source pollution of nitrate with SWAT in the river Dill, Germany

    NASA Astrophysics Data System (ADS)

    Pohlert, T.; Huisman, J. A.; Breuer, L.; Frede, H.-G.

    2005-12-01

    We used the Soil and Water Assessment Tool (SWAT) to simulate point and non-point source pollution of nitrate in a mesoscale mountainous catchment. The results show that the model efficiency for daily discharge is 0.81 for the calibration period (November 1990 to December 1993) and 0.56 for the validation period (April 2000 to January 2003). The model efficiency for monthly nitrate load is 0.66 and 0.77 for the calibration period (April 2000 to March 2002) and validation period (April 2002 to January 2003), respectively. However, the model efficiency for daily loads is low (0.15), which cannot only be attributed to the quality of input data of point source effluents. An analysis of the internal fluxes and cycles of nitrogen pointed out considerable weaknesses in the models conceptualisation of the nitrogen modules which will be improved in future research.

  14. Uncertainty analysis for an effluent trading system in a typical nonpoint-sources-polluted watershed

    PubMed Central

    Chen, Lei; Han, Zhaoxing; Wang, Guobo; Shen, Zhenyao

    2016-01-01

    Conventional effluent trading systems (ETSs) between point sources (PSs) and nonpoint sources (NPSs) are often unreliable because of the uncertain characteristics of NPSs. In this study, a new framework was established for PS-NPS ETSs, and a comprehensive analysis was conducted by quantifying the impacts of the uncertainties associated with the water assimilative capacity (WAC), NPS emissions, and measurement effectiveness. On the basis of these results, the uncertain characteristics of NPSs would result in a less cost-effective PS-NPS ETS during most hydrological periods, and there exists a clear transition occurs from the WAC constraint to the water quality constraint if these stochastic factors are considered. Specifically, the emission uncertainty had a greater impact on PSs, but an increase in the emission or abatement uncertainty caused the abatement efforts to shift from NPSs toward PSs. Moreover, the error transitivity from the WAC to conventional ETS approaches is more obvious than that to the WEFZ-based ETS. When NPSs emissions are relatively high, structural BMPs should be considered for trading, and vice versa. These results are critical to understand the impacts of uncertainty on the functionality of PS-NPS ETSs and to provide a trade-off between the confidence level and abatement efforts. PMID:27406070

  15. Uncertainty analysis for an effluent trading system in a typical nonpoint-sources-polluted watershed.

    PubMed

    Chen, Lei; Han, Zhaoxing; Wang, Guobo; Shen, Zhenyao

    2016-01-01

    Conventional effluent trading systems (ETSs) between point sources (PSs) and nonpoint sources (NPSs) are often unreliable because of the uncertain characteristics of NPSs. In this study, a new framework was established for PS-NPS ETSs, and a comprehensive analysis was conducted by quantifying the impacts of the uncertainties associated with the water assimilative capacity (WAC), NPS emissions, and measurement effectiveness. On the basis of these results, the uncertain characteristics of NPSs would result in a less cost-effective PS-NPS ETS during most hydrological periods, and there exists a clear transition occurs from the WAC constraint to the water quality constraint if these stochastic factors are considered. Specifically, the emission uncertainty had a greater impact on PSs, but an increase in the emission or abatement uncertainty caused the abatement efforts to shift from NPSs toward PSs. Moreover, the error transitivity from the WAC to conventional ETS approaches is more obvious than that to the WEFZ-based ETS. When NPSs emissions are relatively high, structural BMPs should be considered for trading, and vice versa. These results are critical to understand the impacts of uncertainty on the functionality of PS-NPS ETSs and to provide a trade-off between the confidence level and abatement efforts. PMID:27406070

  16. Uncertainty analysis for an effluent trading system in a typical nonpoint-sources-polluted watershed

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Han, Zhaoxing; Wang, Guobo; Shen, Zhenyao

    2016-07-01

    Conventional effluent trading systems (ETSs) between point sources (PSs) and nonpoint sources (NPSs) are often unreliable because of the uncertain characteristics of NPSs. In this study, a new framework was established for PS-NPS ETSs, and a comprehensive analysis was conducted by quantifying the impacts of the uncertainties associated with the water assimilative capacity (WAC), NPS emissions, and measurement effectiveness. On the basis of these results, the uncertain characteristics of NPSs would result in a less cost-effective PS-NPS ETS during most hydrological periods, and there exists a clear transition occurs from the WAC constraint to the water quality constraint if these stochastic factors are considered. Specifically, the emission uncertainty had a greater impact on PSs, but an increase in the emission or abatement uncertainty caused the abatement efforts to shift from NPSs toward PSs. Moreover, the error transitivity from the WAC to conventional ETS approaches is more obvious than that to the WEFZ-based ETS. When NPSs emissions are relatively high, structural BMPs should be considered for trading, and vice versa. These results are critical to understand the impacts of uncertainty on the functionality of PS-NPS ETSs and to provide a trade-off between the confidence level and abatement efforts.

  17. Landscape Planning for Agricultural Non-Point Source Pollution Reduction. II. Balancing Watershed Size, Number of Watersheds, and Implementation Effort

    NASA Astrophysics Data System (ADS)

    Maxted, Jeffrey T.; Diebel, Matthew W.; Vander Zanden, M. Jake

    2009-01-01

    Agricultural non-point source (NPS) pollution poses a severe threat to water quality and aquatic ecosystems. In response, tremendous efforts have been directed toward reducing these pollution inputs by implementing agricultural conservation practices. Although conservation practices reduce pollution inputs from individual fields, scaling pollution control benefits up to the watershed level (i.e., improvements in stream water quality) has been a difficult challenge. This difficulty highlights the need for NPS reduction programs that focus efforts within target watersheds and at specific locations within target watersheds, with the ultimate goal of improving stream water quality. Fundamental program design features for NPS control programs—i.e., number of watersheds in the program, total watershed area, and level of effort expended within watersheds—have not been considered in any sort of formal analysis. Here, we present an optimization model that explores the programmatic and environmental trade-offs between these design choices. Across a series of annual program budgets ranging from 2 to 200 million, the optimal number of watersheds ranged from 3 to 27; optimal watershed area ranged from 29 to 214 km2; and optimal expenditure ranged from 21,000 to 35,000/km2. The optimal program configuration was highly dependent on total program budget. Based on our general findings, we delineated hydrologically complete and spatially independent watersheds ranging in area from 20 to 100 km2. These watersheds are designed to serve as implementation units for a targeted NPS pollution control program currently being developed in Wisconsin.

  18. Impact of spatial rainfall variability on hydrology and nonpoint source pollution modeling

    NASA Astrophysics Data System (ADS)

    Shen, Zhenyao; Chen, Lei; Liao, Qian; Liu, Ruimin; Hong, Qian

    2012-11-01

    Rainfall is regarded as the most important input for the hydrology and nonpoint source (H/NPS) models and uncertainty related to rainfall is generally recognized as a major challenge in watershed modeling. In this paper, we focus on the impact of spatial rainfall variability on H/NPS modeling of a large watershed. The uncertainty introduced by spatial rainfall variability was determined using a number of commonly-used interpolation methods: (1) the Centroid method; (2) the Thiessen Polygon method; (3) the Inverse Distance Weighted (IDW) method; (4) the Dis-Kriging method; and (5) the Co-Kriging method. The Soil and Water Assessment tool (SWAT) was used to quantify the effect of rainfall spatial variability on watershed H/NPS modeling of the Daning watershed in China. Results indicated that these interpolation methods could contribute significant uncertainty in spatial rainfall variability and the carry-magnify effect caused even larger uncertainty in the H/NPS modeling. This uncertainty was magnified from hydrology modeling (stream flow) into NPS modeling (sediment, TP, organic nitrogen (N) and dissolved N). This study further suggested that H/NPS prediction uncertainty relating to spatial rainfall variability was scale-dependent due to the averaging effect of spatial heterogeneity. From a practical point of view, a global interpolation method, such as IDW and Kriging, as well as elevation data derived from a digital elevation model (DEM), should be included into the H/NPS models for reliable predictions in larger watersheds.

  19. Effectiveness of a constructed wetland for retention of nonpoint-source pesticide pollution in the Lourens River catchment, South Africa.

    PubMed

    Schulz, R; Peall, S K

    2001-01-15

    Constructed wetlands have been widely used to control both point- and nonpoint-source pollution in surface waters. However, our knowledge about their effectiveness in retaining agricultural pesticide pollution is limited. A 0.44-ha vegetated wetland built along a tributary of the Lourens River, Western Cape, South Africa, was studied to ascertain retention of runoff-related agricultural pollution. Total suspended solids, orthophosphate, and nitrate were retained in the wetland in the proportions 15, 54, and 70%, respectively, during dry weather conditions (with rainfall less than 2 mm/d) and 78, 75, and 84% during wet conditions (with rainfall between 2 and 35 mm/d). Retention of water-diluted azinphos-methyl introduced via runoff at a level of 0.85 microg/L was between 77 and 93%. Chlorpyrifos and endosulfan were measured during runoff in inlet water at 0.02 and 0.2 microg/L, respectively. However, both pesticides were undetectable in the outlet water samples. During a period of 5 months, an increased concentration of various insecticides was detected in the suspended particles at the wetland inlet: azinphos-methyl, 43 microg/kg; chlorpyrifos, 31 microg/kg; and prothiofos, 6 microg/kg. No organophosphorus pesticides were found in the outlet suspended-particle samples, highlighting the retention capability of the wetland. A toxicological evaluation employing a Chironomus bioassay in situ at the wetland inlet and outlet revealed an 89% reduction in toxicity below the wetland during runoff. PMID:11347620

  20. Long-term agricultural non-point source pollution loading dynamics and correlation with outlet sediment geochemistry

    NASA Astrophysics Data System (ADS)

    Ouyang, Wei; Jiao, Wei; Li, Xiaoming; Giubilato, Elisa; Critto, Andrea

    2016-09-01

    Some agricultural non-point source (NPS) pollutants accumulate in sediments in the outlet sections of watersheds. It is crucial to evaluate the historical interactions between sediment properties and watershed NPS loading. Therefore, a sediment core from the outlet of an agricultural watershed was collected. The core age was dated using the 210Pb method, and sedimentation rates were determined using the constant rate of supply (CRS) model. The total nitrogen (TN), total phosphorus (TP), Cd, Pb, Cu, Ni and Cr accumulations in the sediment generally showed fluctuating increases, with the highest sedimentation fluxes all occurring in approximately 1998. The measurement of specific mass sedimentation rates reflected a record of watershed soil erosion dynamics. Using SWAT (Soil and Water Assessment Tool) to simulate long-term watershed agricultural NPS pollution loadings, the historical interactions between sediment properties and NPS loadings were further evaluated. The N leaching process weakened these interactions, but the historical accumulations of TP and heavy metals in sediments generally correlated well with watershed NPS TP loading. The regression analysis suggested that Pb and Cr were the most suitable indexes for assessing long-term NPS TN and TP pollution, respectively. Assessing the NPS loading dynamics using the vertical characteristics of sediment geochemistry is a new method.

  1. Understanding enabling capacities for managing the 'wicked problem' of nonpoint source water pollution in catchments: a conceptual framework.

    PubMed

    Patterson, James J; Smith, Carl; Bellamy, Jennifer

    2013-10-15

    Nonpoint source (NPS) water pollution in catchments is a 'wicked' problem that threatens water quality, water security, ecosystem health and biodiversity, and thus the provision of ecosystem services that support human livelihoods and wellbeing from local to global scales. However, it is a difficult problem to manage because water catchments are linked human and natural systems that are complex, dynamic, multi-actor, and multi-scalar in nature. This in turn raises questions about understanding and influencing change across multiple levels of planning, decision-making and action. A key challenge in practice is enabling implementation of local management action, which can be influenced by a range of factors across multiple levels. This paper reviews and synthesises important 'enabling' capacities that can influence implementation of local management action, and develops a conceptual framework for understanding and analysing these in practice. Important enabling capacities identified include: history and contingency; institutional arrangements; collaboration; engagement; vision and strategy; knowledge building and brokerage; resourcing; entrepreneurship and leadership; and reflection and adaptation. Furthermore, local action is embedded within multi-scalar contexts and therefore, is highly contextual. The findings highlight the need for: (1) a systemic and integrative perspective for understanding and influencing change for managing the wicked problem of NPS water pollution; and (2) 'enabling' social and institutional arenas that support emergent and adaptive management structures, processes and innovations for addressing NPS water pollution in practice. These findings also have wider relevance to other 'wicked' natural resource management issues facing similar implementation challenges. PMID:23792915

  2. A Spatial and Temporal Assessment of Non-Point Groundwater Pollution Sources, Tutuila Island, American Samoa

    NASA Astrophysics Data System (ADS)

    Shuler, C. K.; El-Kadi, A. I.; Dulaiova, H.; Glenn, C. R.; Fackrell, J.

    2015-12-01

    The quality of municipal groundwater supplies on Tutuila, the main island in American Samoa, is currently in question. A high vulnerability for contamination from surface activities has been recognized, and there exists a strong need to clearly identify anthropogenic sources of pollution and quantify their influence on the aquifer. This study examines spatial relationships and time series measurements of nutrients and other tracers to identify predominant pollution sources and determine the water quality impacts of the island's diverse land uses. Elevated groundwater nitrate concentrations are correlated with areas of human development, however, the mixture of residential and agricultural land use in this unique village based agrarian setting makes specific source identification difficult using traditional geospatial analysis. Spatial variation in anthropogenic impact was assessed by linking NO3- concentrations and δ15N(NO3) from an extensive groundwater survey to land-use types within well capture zones and groundwater flow-paths developed with MODFLOW, a numerical groundwater model. Land use types were obtained from high-resolution GIS data and compared to water quality results with multiple-regression analysis to quantify the impact that different land uses have on water quality. In addition, historical water quality data and new analyses of δD and δ18O in precipitation, groundwater, and mountain-front recharge waters were used to constrain the sources and mechanisms of contamination. Our analyses indicate that groundwater nutrient levels on Tutuila are controlled primarily by residential, not agricultural activity. Also a lack of temporal variation suggests that episodic pollution events are limited to individual water sources as opposed to the entire aquifer. These results are not only valuable for water quality management on Tutuila, but also provide insight into the sustainability of groundwater supplies on other islands with similar hydrogeology and land

  3. 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.

  4. Use of Antibiotic Resistance Analysis To Identify Nonpoint Sources of Fecal Pollution

    PubMed Central

    Wiggins, B. A.; Andrews, R. W.; Conway, R. A.; Corr, C. L.; Dobratz, E. J.; Dougherty, D. P.; Eppard, J. R.; Knupp, S. R.; Limjoco, M. C.; Mettenburg, J. M.; Rinehardt, J. M.; Sonsino, J.; Torrijos, R. L.; Zimmerman, M. E.

    1999-01-01

    A study was conducted to determine the reliability and repeatability of antibiotic resistance analysis as a method of identifying the sources of fecal pollution in surface water and groundwater. Four large sets of isolates of fecal streptococci (from 2,635 to 5,990 isolates per set) were obtained from 236 samples of human sewage and septage, cattle and poultry feces, and pristine waters. The patterns of resistance of the isolates to each of four concentrations of up to nine antibiotics were analyzed by discriminant analysis. When isolates were classified individually, the average rate of correct classification (ARCC) into four possible types (human, cattle, poultry, and wild) ranged from 64 to 78%. When the resistance patterns of all isolates from each sample were averaged and the resulting sample-level resistance patterns were classified, the ARCCs were much higher (96 to 100%). These data confirm that there are measurable and consistent differences in the antibiotic resistance patterns of fecal streptococci isolated from various sources of fecal pollution and that antibiotic resistance analysis can be used to classify and identify these sources. PMID:10427038

  5. Governing change: land-use change and the prevention of nonpoint source pollution in the north coastal basin of California.

    PubMed

    Short, Anne G

    2013-01-01

    Many rural areas in the United States and throughout much of the postindustrial world are undergoing significant ecological, socioeconomic, and political transformations. The migration of urban and suburban dwellers into rural areas has led to the subdivision of large tracts of land into smaller parcels, which can complicate efforts to govern human-environmental problems. Non-point source (NPS) pollution from private rural lands is a particularly pressing human-environmental challenge that may be aggravated by changing land tenure. In this article, I report on a study of the governance and management of sediment (a common NPS pollutant) in the North Coastal basin of California, a region undergoing a transition from traditional extractive and agricultural land uses to rural residential and other alternative land uses. I focus on the differences in the governance and management across private timber, ranch, residential, vacation, and other lands in the region. I find that (1) the stringency and strength of sediment regulations differ by land use, (2) nonregulatory programs tend to target working landscapes, and (3) rural residential landowners have less knowledge of sediment control and report using fewer sediment-control techniques than landowners using their land for timber production or ranching. I conclude with an exploration of the consequences of these differences on an evolving rural landscape. PMID:21805381

  6. A robust simulation-optimization modeling system for effluent trading--a case study of nonpoint source pollution control.

    PubMed

    Zhang, J L; Li, Y P; Huang, G H

    2014-04-01

    In this study, a robust simulation-optimization modeling system (RSOMS) is developed for supporting agricultural nonpoint source (NPS) effluent trading planning. The RSOMS can enhance effluent trading through incorporation of a distributed simulation model and an optimization model within its framework. The modeling system not only can handle uncertainties expressed as probability density functions and interval values but also deal with the variability of the second-stage costs that are above the expected level as well as capture the notion of risk under high-variability situations. A case study is conducted for mitigating agricultural NPS pollution with an effluent trading program in Xiangxi watershed. Compared with non-trading policy, trading scheme can successfully mitigate agricultural NPS pollution with an increased system benefit. Through trading scheme, [213.7, 288.8] × 10(3) kg of TN and [11.8, 30.2] × 10(3) kg of TP emissions from cropped area can be cut down during the planning horizon. The results can help identify desired effluent trading schemes for water quality management with the tradeoff between the system benefit and reliability being balanced and risk aversion being considered. PMID:24366827

  7. PROBABILISTIC ASSESSMENT OF GROUNDWATER VULNERABILITY TO NONPOINT SOURCE POLLUTION IN AGRICULTURAL WATERSHEDS

    EPA Science Inventory

    This paper presents a probabilistic framework for the assessment of groundwater pollution potential by pesticides in two adjacent agricultural watersheds in the Mid-Altantic Coastal Plain. Indices for estimating streams vulnerability to pollutants' load from the surficial aquifer...

  8. Tracking nonpoint nitrogen pollution from urbanizing watersheds (Invited)

    NASA Astrophysics Data System (ADS)

    Kaushal, S.; Groffman, P. M.; Band, L. E.; Elliott, E. M.; Shields, C. A.; Kendall, C.

    2010-12-01

    Nonpoint source nitrogen (N) pollution is a leading contributor of water quality impairments including coastal eutrophication and hypoxia. Improved identification of nonpoint N sources will be critical in prioritizing strategies for watershed N reductions. We combined long-term monitoring, watershed mass balances, and stable isotope source identification methods to investigate impacts of land use and hydrology on transport and transformation of nonpoint source N in forest, agricultural, and urbanized catchments at the Baltimore Ecosystem Study Long-term Ecological Research (LTER) site in Baltimore, Maryland. Human population and wastewater N in residential and suburban areas has doubled over a 50 year period in this region of the Chesapeake Bay watershed and represents an emerging challenge for nonpoint N sources. Mass balances suggested that a substantial proportion of N entering watersheds is retained and transformed based on annual runoff patterns, but that nonpoint sources showed differential susceptibility to watershed N exports in response to climate variability. Isotope data suggested that denitrification in watersheds was removing septic system and agriculturally-derived N, but N from leaking sewers was less susceptible to denitrification. Efforts to reduce nonpoint N sources should enhance watershed denitrification sinks across climatic conditions, and repair of aging urban infrastructure and leaking sewer lines should be a priority. Managing N inputs near streams and below the rooting zone may play a disproportionately large role in regulating N exports in human-dominated watersheds.

  9. Estimating the benefits of land imagery in environmental applications: a case study in nonpoint source pollution of groundwater

    USGS Publications Warehouse

    Bernknopf, Richard L.; Forney, William M.; Raunikar, Ronald P.; Mishra, Shruti K.

    2012-01-01

    Moderate-resolution land imagery (MRLI) is crucial to a more complete assessment of the cumulative, landscape-level effect of agricultural land use and land cover on environmental quality. If this improved assessment yields a net social benefit, then that benefit reflects the value of information (VOI) from MRLI. Environmental quality and the capacity to provide ecosystem services evolve because of human actions, changing natural conditions, and their interaction with natural physical processes. The human actions, in turn, are constrained and redirected by many institutions and regulations such as agricultural, energy, and environmental policies. We present a general framework for bringing together sociologic, biologic, physical, hydrologic, and geologic processes at meaningful scales to interpret environmental implications of MRLI applications. We set out a specific application using MRLI observations to identify crop planting patterns and thus estimate surface management activities that influence groundwater resources over a regional landscape. We tailor the application to the characteristics of nonpoint source groundwater pollution hazards in Iowa to illustrate a general framework in a land use-hydrologic-economic system. In the example, MRLI VOI derives from reducing the risk of both losses to agricultural production and damage to human health and other consequences of contaminated groundwater.

  10. Impacts of DEM uncertainties on critical source areas identification for non-point source pollution control based on SWAT model

    NASA Astrophysics Data System (ADS)

    Xu, Fei; Dong, Guangxia; Wang, Qingrui; Liu, Lumeng; Yu, Wenwen; Men, Cong; Liu, Ruimin

    2016-09-01

    The impacts of different digital elevation model (DEM) resolutions, sources and resampling techniques on nutrient simulations using the Soil and Water Assessment Tool (SWAT) model have not been well studied. The objective of this study was to evaluate the sensitivities of DEM resolutions (from 30 m to 1000 m), sources (ASTER GDEM2, SRTM and Topo-DEM) and resampling techniques (nearest neighbor, bilinear interpolation, cubic convolution and majority) to identification of non-point source (NPS) critical source area (CSA) based on nutrient loads using the SWAT model. The Xiangxi River, one of the main tributaries of Three Gorges Reservoir in China, was selected as the study area. The following findings were obtained: (1) Elevation and slope extracted from the DEMs were more sensitive to DEM resolution changes. Compared with the results of the 30 m DEM, 1000 m DEM underestimated the elevation and slope by 104 m and 41.57°, respectively; (2) The numbers of subwatersheds and hydrologic response units (HRUs) were considerably influenced by DEM resolutions, but the total nitrogen (TN) and total phosphorus (TP) loads of each subwatershed showed higher correlations with different DEM sources; (3) DEM resolutions and sources had larger effects on CSAs identifications, while TN and TP CSAs showed different response to DEM uncertainties. TN CSAs were more sensitive to resolution changes, exhibiting six distribution patterns at all DEM resolutions. TP CSAs were sensitive to source and resampling technique changes, exhibiting three distribution patterns for DEM sources and two distribution patterns for DEM resampling techniques. DEM resolutions and sources are the two most sensitive SWAT model DEM parameters that must be considered when nutrient CSAs are identified.

  11. Water and nonpoint source pollution estimation in the watershed with limited data availability based on hydrological simulation and regression model.

    PubMed

    Huiliang, Wang; Zening, Wu; Caihong, Hu; Xinzhong, Du

    2015-09-01

    Nonpoint source (NPS) pollution is considered as the main reason for water quality deterioration; thus, to quantify the NPS loads reliably is the key to implement watershed management practices. In this study, water quality and NPS loads from a watershed with limited data availability were studied in a mountainous area in China. Instantaneous water discharge was measured through the velocity-area method, and samples were taken for water quality analysis in both flood and nonflood days in 2010. The streamflow simulated by Hydrological Simulation Program-Fortran (HSPF) from 1995 to 2013 and a regression model were used to estimate total annual loads of various water quality parameters. The concentrations of total phosphorus (TP) and total nitrogen (TN) were much higher during the flood seasons, but the concentrations of ammonia nitrogen (NH3-N) and nitrate nitrogen (NO3-N) were lower during the flood seasons. Nevertheless, only TP concentration was positively correlated with the flow rate. The fluctuation of annual load from this watershed was significant. Statistical results indicated the significant contribution of pollutant fluxes during flood seasons to annual fluxes. The loads of TP, TN, NH3-N, and NO3-N in the flood seasons were accounted for 58-85, 60-82, 63-88, 64-81% of the total annual loads, respectively. This study presented a new method for estimation of the water and NPS loads in the watershed with limited data availability, which simplified data collection to watershed model and overcame the scale problem of field experiment method. PMID:25960014

  12. Enabling and Enacting `Practical Action' in Catchments: Responding to the `Wicked Problem' of Nonpoint Source Pollution in Coastal Subtropical Australia

    NASA Astrophysics Data System (ADS)

    Patterson, James J.; Smith, Carl; Bellamy, Jennifer

    2015-02-01

    Enabling and enacting `practical action' (i.e., purposeful and concerted collective action) in catchments is a key challenge in responding to a wide range of pressing catchment and natural resource management (NRM) issues. It is particularly a challenge in responding to `wicked problems,' where generating action is not straightforward and cannot be brought about solely by any single actor, policy or intervention. This paper responds to the critical need to better understand how practical action can be generated in catchments, by conducting an in-depth empirical case study of efforts to manage nonpoint source (NPS) pollution in South East Queensland (SEQ), Australia. SEQ has seen substantial concerted efforts to manage waterway and catchment issues over two decades, yet NPS pollution remains a major problem for waterway health. A novel framework was applied to empirically analyze practical action in three local catchment cases embedded within the broader SEQ region. The analysis focuses on `enabling capacities' underpinning practical action in catchments. Findings reveal that capacities manifested in different ways in different cases, yet many commonalities also occurred across cases. Interplay between capacities was critical to the emergence of adaptive and contextual forms of practical action in all cases. These findings imply that in order to enable and enact practical action in catchments, it is vital to recognize and support a diversity of enabling capacities across both local and regional levels of decision making and action. This is likely to have relevance for other `wicked' catchment and NRM problems requiring local responses within broader multiscalar regional problem situations.

  13. Environmental Kuznets Curve Analysis of the Economic Development and Nonpoint Source Pollution in the Ningxia Yellow River Irrigation Districts in China

    PubMed Central

    Mao, Chunlan; Zhai, Ningning; Yang, Jingchao; Feng, Yongzhong; Cao, Yanchun; Han, Xinhui; Ren, Guangxin; Yang, Gaihe; Meng, Qing-xiang

    2013-01-01

    This study applies the environmental Kuznets curve to test the relationship between the regional economic growth and the different types of agricultural nonpoint source pollution loads in the Ningxia Yellow River irrigation area by using the Johnes export coefficient method. Results show that the pollution load generated by crop cultivation and livestock-breeding industries in the Ningxia Yellow River irrigation area shows an inverted U-shaped feature; however, this feature is absent in living-sewage pollution load. Crop pollution has shown a decreasing trend since 1997 because of the increased per capita income of farmers. Livestock-breeding pollution load reached its turning point when the per capita income of farmers reached 8386.74 RMB. Therefore, an increase in the per capita income of farmers corresponds to an increase in the livestock-breeding pollution load in the Ningxia Yellow River irrigation area. PMID:24171160

  14. Multi-angle Indicators System of Non-point Pollution Source Assessment in Rural Areas: A Case Study Near Taihu Lake

    NASA Astrophysics Data System (ADS)

    Huang, Lei; Ban, Jie; Han, Yu Ting; Yang, Jie; Bi, Jun

    2013-04-01

    This study aims to identify key environmental risk sources contributing to water eutrophication and to suggest certain risk management strategies for rural areas. The multi-angle indicators included in the risk source assessment system were non-point source pollution, deficient waste treatment, and public awareness of environmental risk, which combined psychometric paradigm methods, the contingent valuation method, and personal interviews to describe the environmental sensitivity of local residents. Total risk values of different villages near Taihu Lake were calculated in the case study, which resulted in a geographic risk map showing which village was the critical risk source of Taihu eutrophication. The increased application of phosphorus (P) and nitrogen (N), loss vulnerability of pollutant, and a lack of environmental risk awareness led to more serious non-point pollution, especially in rural China. Interesting results revealed by the quotient between the scores of objective risk sources and subjective risk sources showed what should be improved for each study village. More environmental investments, control of agricultural activities, and promotion of environmental education are critical considerations for rural environmental management. These findings are helpful for developing targeted and effective risk management strategies in rural areas.

  15. Multi-angle indicators system of non-point pollution source assessment in rural areas: a case study near Taihu Lake.

    PubMed

    Huang, Lei; Ban, Jie; Han, Yu Ting; Yang, Jie; Bi, Jun

    2013-04-01

    This study aims to identify key environmental risk sources contributing to water eutrophication and to suggest certain risk management strategies for rural areas. The multi-angle indicators included in the risk source assessment system were non-point source pollution, deficient waste treatment, and public awareness of environmental risk, which combined psychometric paradigm methods, the contingent valuation method, and personal interviews to describe the environmental sensitivity of local residents. Total risk values of different villages near Taihu Lake were calculated in the case study, which resulted in a geographic risk map showing which village was the critical risk source of Taihu eutrophication. The increased application of phosphorus (P) and nitrogen (N), loss vulnerability of pollutant, and a lack of environmental risk awareness led to more serious non-point pollution, especially in rural China. Interesting results revealed by the quotient between the scores of objective risk sources and subjective risk sources showed what should be improved for each study village. More environmental investments, control of agricultural activities, and promotion of environmental education are critical considerations for rural environmental management. These findings are helpful for developing targeted and effective risk management strategies in rural areas. PMID:23456193

  16. 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. PMID:26002368

  17. Evaluation and management of non-point source pollutants in the Lake Tahoe watershed

    SciTech Connect

    Lee, G.F.; Jones-Lee, A.

    1994-12-31

    Lake Tahoe, California-Nevada, one of the most oligotrophic lakes in the world, is experiencing decreased water clarity and increased periphyton growth, and water supplies drawing from the lake are experiencing increased algal-related tastes and odors. The growth of algae in Lake Tahoe is primarily limited by the nitrogen (nitrate and ammonia) loads to the lake, which have been increasing over the years. The nitrogen that is causing the increased fertilization of the lake is primarily derived from atmospheric sources through precipitation onto the lake`s surface. A potentially highly significant source of atmospheric nitrogen in the Lake Tahoe Basin is automobile, bus, and truck engine exhaust discharge of NOx. The fertilization of lawns and other shrubbery, including golf courses, within the Lake Tahoe Basin is also leading to significant growths of attached algae in the nearshore waters of the lake. The fertilizers are transported via groundwater to the nearshore areas of the lake. In order to prevent further deterioration of Lake Tahoe`s eutrophication-related water quality, there is immediate need to control atmospheric input of nitrate and ammonia to the lake`s surface, and to control use of fertilizers on lawns, shrubbery, and golf courses in the watershed. The states of California and Nevada, and the Tahoe Regional Planning Authority need to focus considerable attention on the determination of whether restricting NOx emissions from vehicular traffic within the basin would have a significant beneficial impact on Lake Tahoe`s water clarity.

  18. Sediment composition for the assessment of water erosion and nonpoint source pollution in natural and fire-affected landscapes.

    PubMed

    Carkovic, Athena B; Pastén, Pablo A; Bonilla, Carlos A

    2015-04-15

    Water erosion is a leading cause of soil degradation and a major nonpoint source pollution problem. Many efforts have been undertaken to estimate the amount and size distribution of the sediment leaving the field. Multi-size class water erosion models subdivide eroded soil into different sizes and estimate the aggregate's composition based on empirical equations derived from agricultural soils. The objective of this study was to evaluate these equations on soil samples collected from natural landscapes (uncultivated) and fire-affected soils. Chemical, physical, and soil fractions and aggregate composition analyses were performed on samples collected in the Chilean Patagonia and later compared with the equations' estimates. The results showed that the empirical equations were not suitable for predicting the sediment fractions. Fine particles, including primary clay, primary silt, and small aggregates (<53 μm) were over-estimated, and large aggregates (>53 μm) and primary sand were under-estimated. The uncultivated and fire-affected soils showed a reduced fraction of fine particles in the sediment, as clay and silt were mostly in the form of large aggregates. Thus, a new set of equations was developed for these soils, where small aggregates were defined as particles with sizes between 53 μm and 250 μm and large aggregates as particles>250 μm. With r(2) values between 0.47 and 0.98, the new equations provided better estimates for primary sand and large aggregates. The aggregate's composition was also well predicted, especially the silt and clay fractions in the large aggregates from uncultivated soils (r(2)=0.63 and 0.83, respectively) and the fractions of silt in the small aggregates (r(2)=0.84) and clay in the large aggregates (r(2)=0.78) from fire-affected soils. Overall, these new equations proved to be better predictors for the sediment and aggregate's composition in uncultivated and fire-affected soils, and they reduce the error when estimating soil loss in

  19. EM Sounding Characterization of Soil Environment toward Estimation of Potential Pollutant Load from Non-point Sources

    NASA Astrophysics Data System (ADS)

    Mori, Y.; Ide, J.; Somura, H.; Morisawa, T.

    2010-12-01

    A multi-frequency electro-magnetic (EM) sounding method was applied to agriculture fields to investigate the characteristics of non-point pollution load. Soil environmental properties such as differences in land management were analyzed with electrical conductivity (EC) maps. In addition, vertical EC profiles obtained from EM soundings were compared with EC in drainage ditch or river water. As results, surface soil EC maps successfully extracted the differences in land management affected by fertilizer application. Moreover, surface EC at the vertical profiles strongly related with drainage ditch or river EC, showing most of the EC in the water was explained by surface EC maps at the EM sounding data. The proposed method has strength in obtaining EC data without sampling river water, the situation we sometimes experienced at the field survey.

  20. Monitoring coastal marine waters for spore-forming bacteria of faecal and soil origin to determine point from non-point source pollution.

    PubMed

    Fujioka, R S

    2001-01-01

    The US Environmental Protection Agency (USEPA) and the World Health Organization (WHO) have established recreational water quality standards limiting the concentrations of faecal indicator bacteria (faecal coliform, E. coli, enterococci) to ensure that these waters are safe for swimming. In the application of these hygienic water quality standards, it is assumed that there are no significant environmental sources of these faecal indicator bacteria which are unrelated to direct faecal contamination. However, we previously reported that these faecal indicator bacteria are able to grow in the soil environment of humid tropical island environments such as Hawaii and Guam and are transported at high concentrations into streams and storm drains by rain. Thus, streams and storm drains in Hawaii contain consistently high concentrations of faecal indicator bacteria which routinely exceed the EPA and WHO recreational water quality standards. Since, streams and storm drains eventually flow out to coastal marine waters, we hypothesize that all the coastal beaches which receive run-off from streams and storm drains will contain elevated concentrations of faecal indicator bacteria. To test this hypothesis, we monitored the coastal waters at four beaches known to receive water from stream or storm drains for salinity, turbidity, and used the two faecal indicator bacteria (E. coli, enterococci) to establish recreational water quality standards. To determine if these coastal waters are contaminated with non-point source pollution (streams) or with point source pollution (sewage effluent), these same water samples were also assayed for spore-forming bacteria of faecal origin (Cl. perfringens) and of soil origin (Bacillus species). Using this monitoring strategy it was possible to determine when coastal marine waters were contaminated with non-point source pollution and when coastal waters were contaminated with point source pollution. The results of this study are most likely

  1. Effects of ecological factors and human activities on nonpoint source pollution in the upper reach of the Yangtze River and its management strategies

    NASA Astrophysics Data System (ADS)

    Ding, X. W.; Shen, Z. Y.; Liu, R. M.; Chen, L.; Lin, M.

    2014-01-01

    The effects of ecological and human activities on nonpoint source (NPS) pollution are key issues for sustainable water resources management. In this study, the Improved Export Coefficient Model and the Revised Universal Soil Loss Equation were adopted to estimate the annual loads of NPS pollutants during the period from 1960 through 2003 in the upper reach of the Yangtze River (URYR). Ecological factors and human activities affecting NPS pollution were distinguished and their respective effects were assessed. Variations of the dominant cause (between ecological factors and human activities) were presented. Furthermore, the combined effect of them on NPS pollution were successfully revealed. The results showed that the annual loads raised from ecological factors of dissolved nitrogen (DN) and dissolved phosphorus (DP) were relatively steady from 1960 to 2003. But those of sediment, absorbed nitrogen (AN) and absorbed phosphorus (AP) decreased during that period. In terms of the annual loads caused by human activities, those of dissolved pollutants increased from 1960 to 2000 and then fell. Those of sediment as well as absorbed pollutants peaked in 1980 and then decreased. Simultaneously, the dominant cause of DN loads shifted from ecological factors to human activities after 1980 while DP loads were mainly contributed by human activities. However, sediment, dissolved pollutants were primarily exported by ecological factors. Finally, strategies for managing anthropogenic activities were proposed and their effects on NPS pollution reduction were also depicted quantitatively.

  2. [Ecological mechanisms of the effects of vegetation restoration on the controls of non-point source pollution on barren tableland in Dianchi Watershed of China].

    PubMed

    Wang, Zhen-Hong; Wu, Xue-Can; Li, Ying-Nan

    2006-01-01

    Surface runoff, soil erosion and the leaching of the different forms of nitrogen and phosphorus were observed and the hygroscopic volume of branch and leaves of all plant species and soil penetration were determined to understand the ecological mechanisms of the effects of vegetation restoration on the controls of non-point source pollution on barren tableland in Dianchi Watershed of China. Results indicated that there were significantly relationships between surface runoff volume and the output of non-point pollution matters. The different manmade vegetation systems, consisted respectively of A. nepalensis, A. mearnsii, R. pseudoacacia and V. zizanioides clump, had shown the different potentials to control the leaching of TN, TP, soluble TP, soluble TN. Strong hygroscopic functions of leaves and branch was able to promote the interception of rainfalls and give rise to the less of surface runoff. The leaves, that were small, with low water content, no leathery and have rough face and epidermal wools, were able to got the highly ratio of the hygroscopic volume to above ground fresh standing crops and strengthened the interception of forest canopy. Preparing soil, growth of root system of plant and the natural recovery of vegetation at the gap of trees enhanced surface runoff penetration, as lightened the surface runoff leaching the different forms of nitrogen, phosphorus of soil on the stands. The leaching of different forms of nitrogen and phosphorus went down with the controls of surface runoff in different stands as well. PMID:16599117

  3. Spatial-temporal characteristics of phosphorus in non-point source pollution with grid-based export coefficient model and geographical information system.

    PubMed

    Liu, Ruimin; Dong, Guangxia; Xu, Fei; Wang, Xiujuan; He, Mengchang

    2015-01-01

    In this paper, the spatial changes and trends in non-point source (NPS) total phosphorus (TP) pollution were analyzed by land and non-land uses in the Songliao River Basin from 1986 to 2000 (14 years). A grid-based export coefficient model was used in the process of analysis based on to a geographic information system. The Songliao Basin is divided in four regions: Liaoning province, Jilin province (JL), Heilongjiang province and the eastern part of the Inner Mongolia (IM) Autonomous Region. Results indicated that the NPS phosphorus load caused by land use and non-land use increased steadily from 3.11×10(4) tons in 1986 to 3.49×10(4) tons in 2000. The southeastern region of the Songliao Plain was the most important NPS pollution contributor of all the districts. Although the TP load caused by land use decreased during the studied period in the Songliao River Basin, the contribution of land use to the TP load was dominant compared to non-land uses. The NPS pollution caused by non-land use steadily increased over the studied period. The IM Autonomous Region and JL province had the largest mean annual rate of change among all districts (more than 30%). In this area, livestock and poultry breeding had become one of the most important NPS pollution sources. These areas will need close attention in the future. PMID:26038937

  4. Evaluating the Effects of Land Use Planning for Non-Point Source Pollution Based on a System Dynamics Approach in China

    PubMed Central

    Kuai, Peng; Li, Wei; Liu, Nianfeng

    2015-01-01

    Urbanization is proceeding rapidly in several developing countries such as China. This accelerating urbanization alters the existing land use types in a way that results in more Non-Point Source (NPS) pollution to local surface waters. Reasonable land use planning is necessary. This paper compares seven planning scenarios of a case study area, namely Wulijie, China, from the perspective of NPS pollution. A System Dynamics (SD) model was built for the comparison to adequately capture the planning complexity. These planning scenarios, which were developed by combining different land use intensities (LUIs) and construction speeds (CSs), were then simulated. The results show that compared to scenario S1 (business as usual) all other scenarios will introduce more NPS pollution (with an incremental rate of 22%-70%) to Wulijie. Scenario S6 was selected as the best because it induced relatively less NPS pollution while simultaneously maintaining a considerable development rate. Although LUIs represent a more critical factor compared to CSs, we conclude that both LUIs and CSs need to be taken into account to make the planning more environmentally friendly. Considering the power of SD in decision support, it is recommended that land use planning should take into consideration findings acquired from SD simulations. PMID:26267482

  5. A novel approach combining self-organizing map and parallel factor analysis for monitoring water quality of watersheds under non-point source pollution

    NASA Astrophysics Data System (ADS)

    Zhang, Yixiang; Liang, Xinqiang; Wang, Zhibo; Xu, Lixian

    2015-11-01

    High content of organic matter in the downstream of watersheds underscored the severity of non-point source (NPS) pollution. The major objectives of this study were to characterize and quantify dissolved organic matter (DOM) in watersheds affected by NPS pollution, and to apply self-organizing map (SOM) and parallel factor analysis (PARAFAC) to assess fluorescence properties as proxy indicators for NPS pollution and labor-intensive routine water quality indicators. Water from upstreams and downstreams was sampled to measure dissolved organic carbon (DOC) concentrations and excitation-emission matrix (EEM). Five fluorescence components were modeled with PARAFAC. The regression analysis between PARAFAC intensities (Fmax) and raw EEM measurements indicated that several raw fluorescence measurements at target excitation-emission wavelength region could provide similar DOM information to massive EEM measurements combined with PARAFAC. Regression analysis between DOC concentration and raw EEM measurements suggested that some regions in raw EEM could be used as surrogates for labor-intensive routine indicators. SOM can be used to visualize the occurrence of pollution. Relationship between DOC concentration and PARAFAC components analyzed with SOM suggested that PARAFAC component 2 might be the major part of bulk DOC and could be recognized as a proxy indicator to predict the DOC concentration.

  6. A novel approach combining self-organizing map and parallel factor analysis for monitoring water quality of watersheds under non-point source pollution

    PubMed Central

    Zhang, Yixiang; Liang, Xinqiang; Wang, Zhibo; Xu, Lixian

    2015-01-01

    High content of organic matter in the downstream of watersheds underscored the severity of non-point source (NPS) pollution. The major objectives of this study were to characterize and quantify dissolved organic matter (DOM) in watersheds affected by NPS pollution, and to apply self-organizing map (SOM) and parallel factor analysis (PARAFAC) to assess fluorescence properties as proxy indicators for NPS pollution and labor-intensive routine water quality indicators. Water from upstreams and downstreams was sampled to measure dissolved organic carbon (DOC) concentrations and excitation-emission matrix (EEM). Five fluorescence components were modeled with PARAFAC. The regression analysis between PARAFAC intensities (Fmax) and raw EEM measurements indicated that several raw fluorescence measurements at target excitation-emission wavelength region could provide similar DOM information to massive EEM measurements combined with PARAFAC. Regression analysis between DOC concentration and raw EEM measurements suggested that some regions in raw EEM could be used as surrogates for labor-intensive routine indicators. SOM can be used to visualize the occurrence of pollution. Relationship between DOC concentration and PARAFAC components analyzed with SOM suggested that PARAFAC component 2 might be the major part of bulk DOC and could be recognized as a proxy indicator to predict the DOC concentration. PMID:26526140

  7. Designing Schemes to Mitigate Non-Point Source Water Pollution from Agriculture: The Value of High-Resolution Hydrochemical and Hydrophysical Data

    NASA Astrophysics Data System (ADS)

    Barber, N.; Reaney, S. M.

    2014-12-01

    To effectively mitigate non-point source water pollution from agriculture, first it is vital to have an awareness of a watershed's hydrological and contaminant regime. Understanding the magnitude and timing of pollutant export, as well as the pathways by which different constituents are delivered to a water course, is paramount. One approach to gaining this type of knowledge is to observe pollutant fluxes at the watershed outlet. The River Eden Demonstration Test Catchments programme uses in-situ monitoring equipment to provide high-resolution (30 minute) data for three mixed-agriculture watersheds (ca. 10km2) in north western England. Determinands measured include turbidity, phosphorus, nitrate, chlorophyll-a, dissolved oxygen, conductivity, pH and temperature, along with river discharge and rainfall. Provided with these data, and an awareness of significant agricultural activities carried out in the watershed on an annual basis, this study demonstrates how it is possible to identify different pollutant transfer pathways, along with their spatio-temporal nature, and their relative importance. This information is then used to inform appropriate mitigation design. In relation to this purpose, the pros and cons of the different hydrochemical and hydrophysical data are described, and recommendations made for other determinands that should be considered for measurement in future similar studies.

  8. A review of vegetated buffers and a meta-analysis of their mitigation efficacy in reducing non-point source pollution

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Liu, X.; Zhang, M.; Dahlgren, R. A.; Eitzel, M.

    2009-12-01

    Vegetated buffers are a well-studied and widely used agricultural management practice for reducing non-point source pollution. A wealth of literature provides experimental data on their mitigation efficacy. This paper aggregated many of these results and performed a meta-analysis to quantify the relationships between pollutant removal efficacy and buffer width, buffer slope, soil type, and vegetation type. Theoretical models for removal efficacy (Y) vs. buffer width (w) were derived and tested against data from the surveyed literature using statistical analyses. A model of the form Y = K x (1-exp(-b x w) , (0< K <= 100) successfully captured the relationship between buffer width and pollutant removal, where K reflects the maximum removal efficacy of the buffer and b reflects its probability to remove any single particle of pollutant in a unit distance. The estimates of K were 90.9, 93.2, 92.0, and 89.5 for sediment, pesticides, nitrogen (N) and phosphorus (P), respectively. Buffer width alone explains 37, 60, 44 and 35% of the total variance in removal efficacy for sediment, pesticides, N and P, respectively. Buffer slope was linearly associated with sediment removal efficacy either positively (when slope ≤ 10%) or negatively (when slope > 10%). Buffers composed of trees have higher N and P removal efficacy than buffers composed of grasses or mixtures of grasses and trees. Soil drainage type did not show a significant effect on pollutant removal efficacy. Models for all the studied pollutants were statistically significant with P-values < 0.001. Based on our analysis, a 30 m buffer under favorable slope conditions (≈ 10%) removes over 85% of all the studied pollutants. These models predicting optimal buffer width/slope can be instrumental in the design, implementation and modeling of vegetated buffers for treating agricultural runoff.

  9. Developing a GIS-Based Model to Track Potential Point and Non-Point Sources of Urban Stream Pollution

    NASA Astrophysics Data System (ADS)

    Day, C. A.

    2014-12-01

    Urban streams are often characterized by diminished water quality resulting from an increase in polluted runoff from impervious surfaces. Storm activity further reduces urban stream water quality by temporarily increasing stormwater discharge from sewer overflows. This will often manifest itself in rapid declines of dissolved oxygen and peaks in specific conductivity in response to a rising biochemical oxygen demand which slowly recovers as the pollution load is washed through the stream system. This research developed a GIS-based model to track potential sources of pollution based on the dissolved oxygen and specific conductivity response of urban streams to a series of storm events, within the city of Louisville, Kentucky. Watershed outlet hydrographs were first obtained to determine the lag time of dissolved oxygen drops and specific conductivity peaks in response to set of storm events. Using a digital elevation model and the National Landcover Database, 10m resolution rasters were then created which calculated slope and flow direction/accumulation for both open channel and overland flow conditions across the watersheds. The rasters were merged and converted to flow velocities using a series of storms with different intensities. The final step utilized the Flow Length tool in ArcGIS which calculated the travel time to the watershed outlets from each pixel weighted by the open channel and overland flow conditions. Potential pollution sources could then be located by matching the dissolved oxygen and specific conductivity response lag times to the associated watershed travel times.

  10. Comparative study on nutrient removal of agricultural non-point source pollution for three filter media filling schemes in eco-soil reactors.

    PubMed

    Du, Fuyi; Xie, Qingjie; Fang, Longxiang; Su, Hang

    2016-08-01

    Nutrients (nitrogen and phosphorus) from agricultural non-point source (NPS) pollution have been increasingly recognized as a major contributor to the deterioration of water quality in recent years. The purpose of this article is to investigate the discrepancies in interception of nutrients in agricultural NPS pollution for eco-soil reactors using different filling schemes. Parallel eco-soil reactors of laboratory scale were created and filled with filter media, such as grit, zeolite, limestone, and gravel. Three filling schemes were adopted: increasing-sized filling (I-filling), decreasing-sized filling (D-filling), and blend-sized filling (B-filling). The systems were intermittent operations via simulated rainstorm runoff. The nutrient removal efficiency, biomass accumulation and vertical dissolved oxygen (DO) distribution were defined to assess the performance of eco-soil. The results showed that B-filling reactor presented an ideal DO for partial nitrification-denitrification across the eco-soil, and B-filling was the most stable in the change of bio-film accumulation trends with depth in the three fillings. Simultaneous and highest removals of NH4(+)-N (57.74-70.52%), total nitrogen (43.69-54.50%), and total phosphorus (42.50-55.00%) were obtained in the B-filling, demonstrating the efficiency of the blend filling schemes of eco-soil for oxygen transfer and biomass accumulation to cope with agricultural NPS pollution. PMID:27441855

  11. 40 CFR 125.64 - Effect of the discharge on other point and nonpoint sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 22 2011-07-01 2011-07-01 false Effect of the discharge on other point... § 125.64 Effect of the discharge on other point and nonpoint sources. (a) No modified discharge may result in any additional pollution control requirements on any other point or nonpoint source. (b)...

  12. 40 CFR 125.64 - Effect of the discharge on other point and nonpoint sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Effect of the discharge on other point... § 125.64 Effect of the discharge on other point and nonpoint sources. (a) No modified discharge may result in any additional pollution control requirements on any other point or nonpoint source. (b)...

  13. Mitigation efficacy of vegetated buffers in reducing non-point source pollution: A critical review and meta-analysis

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Liu, X.; Zhang, M.; Dahlgren, R.; Eitzel, M.

    2008-12-01

    Vegetated buffers are the most studied and widely used agricultural management practice for reducing non- point source pollution. A wealth of existing literature provides experimental data on their mitigation efficacy. This paper aggregated many of these results and performed a meta-analysis on them to quantify the relationships between pollutant removal efficacy and buffer width and buffer slope. Theoretical models for removal efficacy (Y) vs. buffer width (w) were derived and tested against data from the surveyed literature using statistical analyses. A model of the form \\Y = K (1 - exp (-bw)) , (0< K ≤100) is shown to successfully capture the relationship between buffer width and pollutant removal, where K reflects the removal capacity of the buffer and b reflects its probability to remove any single particle of pollutant in a unit distance. The estimates of K are 90.9, 93.2, 92.0, and 89.5 for sediment, pesticides, nitrogen (N) and phosphorus (P), respectively. Buffer width alone explains 37, 60, 44 and 35% of the total variance in removal efficacy for sediment, pesticides, N and P. Buffer slope is linearly associated with sediment removal efficacy either positively (when slope ≤9%) or negatively (when slope >9%). A sediment removal model based on buffer width and buffer slope explains 55.8% of the total variation in removal efficacy. Models for all the studied pollutants are statistically significant with P-values <0.001. Based on our analysis, a 30 m buffer removes over 80% of all the studied pollutants. These models predicting optimal buffer width/slope could be instrumental in the implementation and design of vegetated buffers for treating agricultural runoff to meet specific water quality objectives. The quantitative relationship established also provides valuable information for modeling buffer efficacy at the watershed scale.

  14. 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...

  15. Contingent Valuation of Residents' Attitudes and Willingness-to-Pay for Non-point Source Pollution Control: A Case Study in AL-Prespa, Southeastern Albania.

    PubMed

    Grazhdani, Dorina

    2015-07-01

    Recently, local governments in Albania have begun paying attention to management of small watershed, because there are specific boundaries and people living within a watershed basin tend to be more concerned about the basin's environmental, economic, and social development. But this natural resource management and non-point source (NPS) pollution control is still facing challenges. Albanian part of Prespa Park (AL-Prespa) is a good case study, as it is a protected wetland area of high biodiversity and long human history. In this framework, this study was undertaken, the main objectives of which were to explore: (1) the attitudes of the residents toward NPS pollution control, (2) their willingness-to-pay for improving water quality, and (3) factors affecting the residents' willingness-to-pay. Descriptive statistics, one-way ANOVA (analysis of variance), Chi-square analysis, and multivariate data analysis techniques were used. Findings strongly suggested that the residents' attitudes toward NPS pollution control in this area were positive. With the combination of two major contingent valuation methods--dichotomous choice and open-ended formats, the survey results indicated that the average yearly respondents' WTP was 6.4. The survey revealed that residents' yearly income and education level were the main factors affecting residents' willingness-to-pay for NPS pollution control in this area, and there was no significant correlation between residents' yearly income and their education level. The current study would lay a solid foundation on decision-making in further NPS pollution control and public participation through community-based watershed management policies in AL-Prespa watershed and similar areas. PMID:25860594

  16. Contingent Valuation of Residents' Attitudes and Willingness-to-Pay for Non-point Source Pollution Control: A Case Study in AL-Prespa, Southeastern Albania

    NASA Astrophysics Data System (ADS)

    Grazhdani, Dorina

    2015-07-01

    Recently, local governments in Albania have begun paying attention to management of small watershed, because there are specific boundaries and people living within a watershed basin tend to be more concerned about the basin's environmental, economic, and social development. But this natural resource management and non-point source (NPS) pollution control is still facing challenges. Albanian part of Prespa Park (AL-Prespa) is a good case study, as it is a protected wetland area of high biodiversity and long human history. In this framework, this study was undertaken, the main objectives of which were to explore: (1) the attitudes of the residents toward NPS pollution control, (2) their willingness-to-pay for improving water quality, and (3) factors affecting the residents' willingness-to-pay. Descriptive statistics, one-way ANOVA (analysis of variance), Chi-square analysis, and multivariate data analysis techniques were used. Findings strongly suggested that the residents' attitudes toward NPS pollution control in this area were positive. With the combination of two major contingent valuation methods—dichotomous choice and open-ended formats, the survey results indicated that the average yearly respondents' WTP was €6.4. The survey revealed that residents' yearly income and education level were the main factors affecting residents' willingness-to-pay for NPS pollution control in this area, and there was no significant correlation between residents' yearly income and their education level. The current study would lay a solid foundation on decision-making in further NPS pollution control and public participation through community-based watershed management policies in AL-Prespa watershed and similar areas.

  17. Spatio-temporal variation of erosion-type non-point source pollution in a small watershed of hilly and gully region, Chinese Loess Plateau.

    PubMed

    Wu, Lei; Liu, Xia; Ma, Xiao-Yi

    2016-06-01

    Loss of nitrogen and phosphorus in the hilly and gully region of Chinese Loess Plateau not only decreases the utilization rate of fertilizer but also is a potential threat to aquatic environments. In order to explore the process of erosion-type non-point source (NPS) pollution in Majiagou watershed of Loess Plateau, a distributed, dynamic, and integrated NPS pollution model was established to investigate impacts of returning farmland on erosion-type NPS pollution load from 1995 to 2012. Results indicate that (1) the integrated model proposed in this study was verified to be reasonable; the general methodology is universal and can be applicable to the hilly and gully region, Loess Plateau; (2) the erosion-type NPS total nitrogen (TN) and total phosphorus (TP) load showed an overall decreasing trend; the average nitrogen and phosphorus load modulus in the last four years (2009-2012) were 1.23 and 1.63 t/km(2) · a, respectively, which were both decreased by about 35.4 % compared with the initial treatment period (1995-1998); and (3) The spatial variations of NPS pollution are closely related to spatial characteristics of rainfall, topography, and soil and land use types; the peak regions of TN and TP loss mainly occurred along the main river banks of the Yanhe River watershed from northeast to southeast, and gradually decreased with the increase of distance to the left and right river banks, respectively. Results may provide scientific basis for the watershed-scale NPS pollution control of the Loess Plateau. PMID:26898934

  18. A simulation-based interval two-stage stochastic model for agricultural non-point source pollution control through land retirement.

    PubMed

    Luo, B; Li, J B; Huang, G H; Li, H L

    2006-05-15

    This study presents a simulation-based interval two-stage stochastic programming (SITSP) model for agricultural non-point source (NPS) pollution control through land retirement under uncertain conditions. The modeling framework was established by the development of an interval two-stage stochastic program, with its random parameters being provided by the statistical analysis of the simulation outcomes of a distributed water quality approach. The developed model can deal with the tradeoff between agricultural revenue and "off-site" water quality concern under random effluent discharge for a land retirement scheme through minimizing the expected value of long-term total economic and environmental cost. In addition, the uncertainties presented as interval numbers in the agriculture-water system can be effectively quantified with the interval programming. By subdividing the whole agricultural watershed into different zones, the most pollution-related sensitive cropland can be identified and an optimal land retirement scheme can be obtained through the modeling approach. The developed method was applied to the Swift Current Creek watershed in Canada for soil erosion control through land retirement. The Hydrological Simulation Program-FORTRAN (HSPF) was used to simulate the sediment information for this case study. Obtained results indicate that the total economic and environmental cost of the entire agriculture-water system can be limited within an interval value for the optimal land retirement schemes. Meanwhile, a best and worst land retirement scheme was obtained for the study watershed under various uncertainties. PMID:16242757

  19. Synergistic impacts of land-use change and soil property variation on non-point source nitrogen pollution in a freeze-thaw area

    NASA Astrophysics Data System (ADS)

    Ouyang, Wei; Huang, Haobo; Hao, Fanghua; Guo, Bobo

    2013-07-01

    Quantifying the non-point source (NPS) nitrogen pollution response to the varied land-use and soil properties in highly agricultural regions is critical for the proper management of NPS pollution. This study simulated the NPS nitrogen loading responses to variations of land-use and soil from 1979 to 2009. The Soil and Water Assessment Tool (SWAT) was used to model the NPS organic nitrogen and nitrate loading in a freeze-thaw area in northeast China. The temporal-spatial simulations of land-use in four periods indicated that the NPS nitrogen loading responded to the disappearance of wetlands and the conversion of uplands to paddy rice. After updating the soil data, the watershed NPS nitrogen loading decreased, and the spatial distribution of the loading indicated that the NPS organic nitrogen was more sensitive than was the nitrate to soil variation. F-tests were employed to assess the significance of each of the predictor variables in five types of scenarios. Overall, the results indicate that the watershed NPS nitrogen loading is sensitive to changes of soil and land-use, but soil changes have a more significant impact. The results of this study also suggest that temperature has significant effects on NPS nitrogen yield and that it caused the twin peaks in the temporal scale. Increasing the temperature above zero in April caused a temporal shift in soil water movement and transported nitrogen pollution earlier in the year, causing an increased loading in water before the summer irrigation, which is advantageous for NPS nitrogen pollution control.

  20. Support vector machine-an alternative to artificial neuron network for water quality forecasting in an agricultural nonpoint source polluted river?

    PubMed

    Liu, Mei; Lu, Jun

    2014-09-01

    Water quality forecasting in agricultural drainage river basins is difficult because of the complicated nonpoint source (NPS) pollution transport processes and river self-purification processes involved in highly nonlinear problems. Artificial neural network (ANN) and support vector model (SVM) were developed to predict total nitrogen (TN) and total phosphorus (TP) concentrations for any location of the river polluted by agricultural NPS pollution in eastern China. River flow, water temperature, flow travel time, rainfall, dissolved oxygen, and upstream TN or TP concentrations were selected as initial inputs of the two models. Monthly, bimonthly, and trimonthly datasets were selected to train the two models, respectively, and the same monthly dataset which had not been used for training was chosen to test the models in order to compare their generalization performance. Trial and error analysis and genetic algorisms (GA) were employed to optimize the parameters of ANN and SVM models, respectively. The results indicated that the proposed SVM models performed better generalization ability due to avoiding the occurrence of overtraining and optimizing fewer parameters based on structural risk minimization (SRM) principle. Furthermore, both TN and TP SVM models trained by trimonthly datasets achieved greater forecasting accuracy than corresponding ANN models. Thus, SVM models will be a powerful alternative method because it is an efficient and economic tool to accurately predict water quality with low risk. The sensitivity analyses of two models indicated that decreasing upstream input concentrations during the dry season and NPS emission along the reach during average or flood season should be an effective way to improve Changle River water quality. If the necessary water quality and hydrology data and even trimonthly data are available, the SVM methodology developed here can easily be applied to other NPS-polluted rivers. PMID:24894753

  1. Metamodels and nonpoint pollution policy in agriculture

    NASA Astrophysics Data System (ADS)

    Bouzaher, Aziz; Lakshminarayan, P. G.; Cabe, Richard; Carriquiry, Alicia; Gassman, Philip W.; Shogren, Jason F.

    1993-06-01

    Complex mathematical simulation models are generally used for quantitative measurement of the fate of agricultural chemicals in soil. But it is less efficient to use them directly for regional water quality assessments because of the large number of simulations required to cover the entire region and because the entire set of simulation runs must be repeated for each new policy. To make regional water quality impact assessment on a timely basis, a simplified technique called metamodeling is suggested. A metamodel summarizes the input-output relationships in a complex simulation model designed to mimic actual processes such as groundwater leaching. Metamodels are constructed and validated to predict groundwater and surface water concentrations of major corn and sorghum herbicides in the Corn Belt and Lake States regions of the United States. The usefulness of metamodeling in the evaluation of agricultural nonpoint pollution policies is illustrated using an integrated environmental economic modeling system. For the baseline scenario, we estimate that 1.2% of the regional soils will lead to groundwater detection of atrazine exceeding 0.12 Mg/L, which compares well with the findings of an Environmental Protection Agency monitoring survey. The results suggest no-till practices could significantly reduce surface water concentration and a water quality policy, such as an atrazine ban, could increase soil erosion despite the conservation compliance provisions.

  2. Geospatial data resampling and resolution effects on watershed modeling: A case study using the agricultural non-point source pollution model

    NASA Astrophysics Data System (ADS)

    Usery, E. Lynn; Finn, Michael P.; Scheidt, Douglas J.; Ruhl, Sheila; Beard, Thomas; Bearden, Morgan

    2004-10-01

    Researchers have been coupling geographic information systems (GIS) data handling and processing capability to watershed and water-quality models for many years. This capability is suited for the development of databases appropriate for water modeling. However, it is rare for GIS to provide direct inputs to the models. To demonstrate the logical procedure of coupling GIS for model parameter extraction, we selected the Agricultural Non-Point Source (AGNPS) pollution model. Investigators can generate data layers at various resolutions and resample to pixel sizes to support models at particular scales. We developed databases of elevation, land cover, and soils at various resolutions in four watersheds. The ability to use multiresolution databases for the generation of model parameters is problematic for grid-based models. We used database development procedures and observed the effects of resolution and resampling on GIS input datasets and parameters generated from those inputs for AGNPS. Results indicate that elevation values at specific points compare favorably between 3- and 30-m raster datasets. Categorical data analysis indicates that land cover classes vary significantly. Derived parameters parallel the results of the base GIS datasets. Analysis of data resampled from 30-m to 60-, 120-, 210-, 240-, 480-, 960-, and 1920-m pixels indicates a general degradation of both elevation and land cover correlations as resolution decreases. Initial evaluation of model output values for soluble nitrogen and phosphorous indicates similar degradation with resolution.

  3. A paddy eco-ditch and wetland system to reduce non-point source pollution from rice-based production system while maintaining water use efficiency.

    PubMed

    Xiong, Yujiang; Peng, Shizhang; Luo, Yufeng; Xu, Junzeng; Yang, Shihong

    2015-03-01

    Non-point source (NPS) pollution from agricultural drainage has aroused widespread concerns throughout the world due to its contribution to eutrophication of water bodies. To remove nitrogen (N) and phosphorus (P) from agricultural drainage in situ, a Paddy Eco-ditch and Wetland System (PEDWS) was designed and built based on the characteristics of the irrigated rice district. A 2-year (2012-2013) field experiment was conducted to evaluate the performance of this system in Gaoyou Irrigation District in Eastern China. The results showed that the reduction in water input in paddy field of the PEDWS enabled the maintenance of high rice yield; it significantly increased irrigation water productivity (WPI), gross water productivity (WPG), and evapotranspiration water productivity (WPET) by 109.2, 67.1, and 17.6%, respectively. The PEDWS dramatically decreased N and P losses from paddy field. Compared with conventional irrigation and drainage system (CIDS), the amount of drainage water from PEDWS was significantly reduced by 56.2%, the total nitrogen (TN) concentration in drainage was reduced by 42.6%, and thus the TN and total phosphorus (TP) losses were reduced by 87.8 and 70.4%. PEDWS is technologically feasible and applicable to treat nutrient losses from paddy fields in situ and can be used in similar areas. PMID:25304242

  4. Geospatial data resampling and resolution effects on watershed modeling: A case study using the agricultural non-point source pollution model

    USGS Publications Warehouse

    Usery, E.L.; Finn, M.P.; Scheidt, D.J.; Ruhl, S.; Beard, T.; Bearden, M.

    2004-01-01

    Researchers have been coupling geographic information systems (GIS) data handling and processing capability to watershed and waterquality models for many years. This capability is suited for the development of databases appropriate for water modeling. However, it is rare for GIS to provide direct inputs to the models. To demonstrate the logical procedure of coupling GIS for model parameter extraction, we selected the Agricultural Non-Point Source (AGNPS) pollution model. Investigators can generate data layers at various resolutions and resample to pixel sizes to support models at particular scales. We developed databases of elevation, land cover, and soils at various resolutions in four watersheds. The ability to use multiresolution databases for the generation of model parameters is problematic for grid-based models. We used database development procedures and observed the effects of resolution and resampling on GIS input datasets and parameters generated from those inputs for AGNPS. Results indicate that elevation values at specific points compare favorably between 3- and 30-m raster datasets. Categorical data analysis indicates that land cover classes vary significantly. Derived parameters parallel the results of the base GIS datasets. Analysis of data resampled from 30-m to 60-, 120-, 210-, 240-, 480-, 960-, and 1920-m pixels indicates a general degradation of both elevation and land cover correlations as resolution decreases. Initial evaluation of model output values for soluble nitrogen and phosphorous indicates similar degradation with resolution. ?? Springer-Verlag 2004.

  5. [Accumulation of non-point source pollutants in ditch wetland and their uptake and purification by plants].

    PubMed

    Jiang, Cuiling; Fan, Xiaoqiu; Zhang, Yibing

    2005-07-01

    The study on the vertical and horizontal distribution of organic matters and total nitrogen (TN) in the sediment of ditch wetland naturally grown with reed (Phragmites communis) and wild rice (Zizania latifolia) showed that the sediment below 40 cm depth had a significant effectiveness in retaining and accumulating organic matters and TN, but in its surface layer, this effectiveness varied largely with seasons, and the maximum was more than twofold of the minimum. TN was highly correlated with organic matters, the correlation coefficient being 0.9876 in reed wetland and 0.9335 in wild rice wetland, and in water phase, it was positively related to NH4+ -N and NO3-N, indicating that the main composition of TN was organic N, and the mineralization of organic N was the sources of inorganic N. The harvest of reed in each autumn could take away 818 kg x hm(-2) of N and 103.6 kg x hm(-2) of P, and that of wild rice could take away 131 kg x hm(-2) of N and 28.9 kg x hm(-2) of P. Zizania caduci flora had a high assimilation ability of nutrients. Its cultivation in ditch wetland to replace wild helophytes would be a good approach to attain higher absorbing ability of N and P, and to resolve the secondary pollution problem of emerged plants, because farmers could harvest it voluntarily. PMID:16252882

  6. A MODELING-GIS APPROACH FOR THE ASSESSMENT OF SOIL AND GROUND WATER VULNERABILITY TO NONPOINT SOURCE IN AGRICULTURAL WATERSHEDS

    EPA Science Inventory

    Ground water pollution due to agriculture activities is a major source of concern. Vast agricultural lands constitute a nonpoint source for pollutants, such as pesticides and nitrogen fertilizers, which threatens ground water resources and the integrity of aquatic and terrestria...

  7. Identification of Nonpoint Sources of Fecal Pollution in Coastal Waters by Using Host-Specific 16S Ribosomal DNA Genetic Markers from Fecal Anaerobes

    PubMed Central

    Bernhard, Anne E.; Field, Katharine G.

    2000-01-01

    We describe a new PCR-based method for distinguishing human and cow fecal contamination in coastal waters without culturing indicator organisms, and we show that the method can be used to track bacterial marker sequences in complex environments. We identified two human-specific genetic markers and five cow-specific genetic markers in fecal samples by amplifying 16S ribosomal DNA (rDNA) fragments from members of the genus Bifidobacterium and the Bacteroides-Prevotella group and performing length heterogeneity PCR and terminal restriction fragment length polymorphism analyses. Host-specific patterns suggested that there are species composition differences in the Bifidobacterium and Bacteroides-Prevotella populations of human and cow feces. The patterns were highly reproducible among different hosts belonging to the same species. Additionally, all host-specific genetic markers were detected in water samples collected from areas frequently contaminated with fecal pollution. Ease of detection and longer survival in water made Bacteroides-Prevotella indicators better than Bifidobacterium indicators. Fecal 16S rDNA sequences corresponding to our Bacteroides-Prevotella markers comprised closely related gene clusters, none of which exactly matched previously published Bacteroides or Prevotella sequences. Our method detected host-specific markers in water at pollutant concentrations of 2.8 × 10−5 to 2.8 × 10−7 g (dry weight) of feces/liter and 6.8 × 10−7 g (dry weight) of sewage/liter. Although our aim was to identify nonpoint sources of fecal contamination, the method described here should be widely applicable for monitoring spatial and temporal fluctuations in specific bacterial groups in natural environments. PMID:10742246

  8. Compliance Groundwater Monitoring of Nonpoint Sources - Emerging Approaches

    NASA Astrophysics Data System (ADS)

    Harter, T.

    2008-12-01

    and its typically large spatial extend requires extensive networks at an individual site to accurately and fairly monitor individual compliance. In contrast, regional networks seemingly fail to hold individual landowners accountable. But regional networks can effectively monitor large-scale impacts and water quality trends; and thus inform regulatory programs that enforce management practices tied to nonpoint source pollution. Regional monitoring networks for compliance purposes can face significant challenges in the implementation due to a regulatory and legal landscape that is exclusively structured to address point sources and individual liability, and due to the non-intensive nature of a regional monitoring program (lack of control of hot spots; lack of accountability of individual landowners).

  9. A coupled model approach to reduce nonpoint-source pollution resulting from predicted urban growth: A case study in the Ambos Nogales watershed

    USGS Publications Warehouse

    Norman, L.M.; Guertin, D.P.; Feller, M.

    2008-01-01

    The development of new approaches for understanding processes of urban development and their environmental effects, as well as strategies for sustainable management, is essential in expanding metropolitan areas. This study illustrates the potential of linking urban growth and watershed models to identify problem areas and support long-term watershed planning. Sediment is a primary source of nonpoint-source pollution in surface waters. In urban areas, sediment is intermingled with other surface debris in transport. In an effort to forecast the effects of development on surface-water quality, changes predicted in urban areas by the SLEUTH urban growth model were applied in the context of erosion-sedimentation models (Universal Soil Loss Equation and Spatially Explicit Delivery Models). The models are used to simulate the effect of excluding hot-spot areas of erosion and sedimentation from future urban growth and to predict the impacts of alternative erosion-control scenarios. Ambos Nogales, meaning 'both Nogaleses,' is a name commonly used for the twin border cities of Nogales, Arizona and Nogales, Sonora, Mexico. The Ambos Nogales watershed has experienced a decrease in water quality as a result of urban development in the twin-city area. Population growth rates in Ambos Nogales are high and the resources set in place to accommodate the rapid population influx will soon become overburdened. Because of its remote location and binational governance, monitoring and planning across the border is compromised. One scenario described in this research portrays an improvement in water quality through the identification of high-risk areas using models that simulate their protection from development and replanting with native grasses, while permitting the predicted and inevitable growth elsewhere. This is meant to add to the body of knowledge about forecasting the impact potential of urbanization on sediment delivery to streams for sustainable development, which can be

  10. A novel modelling framework to prioritize estimation of non-point source pollution parameters for quantifying pollutant origin and discharge in urban catchments.

    PubMed

    Fraga, I; Charters, F J; O'Sullivan, A D; Cochrane, T A

    2016-02-01

    Stormwater runoff in urban catchments contains heavy metals (zinc, copper, lead) and suspended solids (TSS) which can substantially degrade urban waterways. To identify these pollutant sources and quantify their loads the MEDUSA (Modelled Estimates of Discharges for Urban Stormwater Assessments) modelling framework was developed. The model quantifies pollutant build-up and wash-off from individual impervious roof, road and car park surfaces for individual rain events, incorporating differences in pollutant dynamics between surface types and rainfall characteristics. This requires delineating all impervious surfaces and their material types, the drainage network, rainfall characteristics and coefficients for the pollutant dynamics equations. An example application of the model to a small urban catchment demonstrates how the model can be used to identify the magnitude of pollutant loads, their spatial origin and the response of the catchment to changes in specific rainfall characteristics. A sensitivity analysis then identifies the key parameters influencing each pollutant load within the stormwater given the catchment characteristics, which allows development of a targeted calibration process that will enhance the certainty of the model outputs, while minimizing the data collection required for effective calibration. A detailed explanation of the modelling framework and pre-calibration sensitivity analysis is presented. PMID:26613353

  11. Relating landscape characteristics to non-point source pollution in mine waste-located watersheds using geospatial techniques.

    PubMed

    Xiao, Huaguo; Ji, Wei

    2007-01-01

    Landscape characteristics of a watershed are important variables that influence surface water quality. Understanding the relationship between these variables and surface water quality is critical in predicting pollution potential and developing watershed management practices to eliminate or reduce pollution risk. To understand the impacts of landscape characteristics on water quality in mine waste-located watersheds, we conducted a case study in the Tri-State Mining District which is located in the conjunction of three states (Missouri, Kansas and Oklahoma). Severe heavy metal pollution exists in that area resulting from historical mining activities. We characterized land use/land cover over the last three decades by classifying historical multi-temporal Landsat imagery. Landscape metrics such as proportion, edge density and contagion were calculated based on the classified imagery. In-stream water quality data over three decades were collected, including lead, zinc, iron, cadmium, aluminum and conductivity which were used as key water quality indicators. Statistical analyses were performed to quantify the relationship between landscape metrics and surface water quality. Results showed that landscape characteristics in mine waste-located watersheds could account for as much as 77% of the variation of water quality indicators. A single landscape metric alone, such as proportion of mine waste area, could be used to predict surface water quality; but its predicting power is limited, usually accounting for less than 60% of the variance of water quality indicators. PMID:16551489

  12. Evaluating spatial interaction of soil property with non-point source pollution at watershed scale: the phosphorus indicator in Northeast China.

    PubMed

    Ouyang, Wei; Huang, Haobo; Hao, Fanghua; Shan, Yushu; Guo, Bobo

    2012-08-15

    To better understand the spatial dynamics of non-point source (NPS) phosphorus loading with soil property at watershed scale, integrated modeling and soil chemistry is crucial to ensure that the indicator is functioning properly and expressing the spatial interaction at two depths. Developments in distributed modeling have greatly enriched the availability of geospatial data analysis and assess the NPS pollution loading response to soil property over larger area. The 1.5 km-grid soil sampling at two depths was analyzed with eight parameters, which provided detailed spatial and vertical soil data under four main types of landuses. The impacts of landuse conversion and agricultural practice on soil property were firstly identified. Except for the slightly bigger total of potassium (TK) and cadmium (Cr), the other six parameters had larger content in 20-40 cm surface than the top 20 cm surface. The Soil and Water Assessment Tool was employed to simulate the loading of NPS phosphorus. Overlaying with the landuse distribution, it was found that the NPS phosphorus mainly comes from the subbasins dominated with upland and paddy rice. The linear correlations of eight soil parameters at two depths with NPS phosphorus loading in the subbasins of upland and paddy rice were compared, respectively. The correlations of available phosphorus (AP), total phosphorus (TP), total nitrogen (TN) and TK varied in two depths, and also can assess the loading. The soil with lower soil organic carbon (SOC) presented a significant higher risk for NPS phosphorus loading, especially in agricultural area. The Principal Component Analysis showed that the TP and zinc (Zn) in top soil and copper (Cu) and Cr in subsurface can work as indicators. The analysis suggested that the application of soil property indicators is useful for assessing NPS phosphorus loss, which is promising for water safety in agricultural area. PMID:22771816

  13. Incorporation of Complex Hydrological and Socio-economic Factors for Non-point Source Pollution Control: A Case Study at the Yincungang Canal, the Lake Tai Basin of China

    NASA Astrophysics Data System (ADS)

    Yang, X.; Luo, X.; Zheng, Z.

    2012-04-01

    It is increasingly realized that non-point pollution sources contribute significantly to water environment deterioration in China. Compared to developed countries, non-point source pollution in China has the unique characteristics of strong intensity and composition complexity due to its special socioeconomic conditions. First, more than 50% of its 1.3 billion people are rural. Sewage from the majority of the rural households is discharged either without or only with minimal treatment. The large amount of erratic rural sewage discharge is a significant source of water pollution. Second, China is plagued with serious agricultural pollution due to widespread improper application of fertilizers and pesticides. Finally, there lack sufficient disposal and recycling of rural wastes such as livestock manure and crop straws. Pollutant loads from various sources have far exceeded environmental assimilation capacity in many parts of China. The Lake Tai basin is one typical example. Lake Tai is the third largest freshwater lake in China. The basin is located in the highly developed and densely populated Yangtze River Delta. While accounting for 0.4% of its land area and 2.9% of its population, the Lake Tai basin generates more than 14% of China's Gross Domestic Production (GDP), and the basin's GDP per capita is 3.5 times as much as the state average. Lake Tai is vital to the basin's socio-economic development, providing multiple services including water supply for municipal, industrial, and agricultural needs, navigation, flood control, fishery, and tourism. Unfortunately, accompanied with the fast economic development is serious water environment deterioration in the Lake Tai basin. The lake is becoming increasingly eutrophied and has frequently suffered from cyanobacterial blooms in recent decades. Chinese government has made tremendous investment in order to mitigate water pollution conditions in the basin. Nevertheless, the trend of deteriorating water quality has yet to

  14. Synthesis and application of lignin-based copolymer LSAA on controlling non-point source pollution resulted from surface runoff.

    PubMed

    Liu, Chen; Wu, Guangxia; Mu, Huanzhen; Yuan, Zonghuan; Tang, Lianyi; Lin, Xiangwei

    2008-01-01

    In this article, alkali lignin separated from paper pulp waste was grafted into a novel copolymer LSAA (a copolymer of lignin, starch, acrylamide, and acrylic acid). Its practical application effect and environmental safety were studied. The results of field simulation experiment indicated that the application of LSAA significantly affected the output of the runoff and pollutants. The runoff quantity was decreased by 16.67%-47.00% and the loads of total suspended solids (TSS), chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) were reduced by 17.78%-62.14%, 26.32%-59.91%, 15.25%-47.42%, and 22.18%-52.78%, respectively. The tests on its environmental safety showed that LSAA did no harm the soil. Compared with polyacrylamide (PAM), a dominant product in this field, LSAA exhibited similar effects and cheap cost. Thus, this study not only created a new product for controlling runoff water quality but also offered a beneficial application for industrial paper waste. PMID:18814577

  15. [Dynamic change of non-point source pollution exported from Heigou watershed in Three Gorges Reservoir area].

    PubMed

    Tian, Yao-Wu; Huang, Zhi-Lin; Xiao, Wen-Fa

    2011-02-01

    Sediment and its associated pollutants entering a water body can be very destructive to the ecological health of that system. Based on GIS and AnnAGNPS model, A total of 60 combinations of various management treatments including five fertilizer levels (FL1-existing, FL2-70% of existing, FL3-recommended, FLA-70% of recommended, FL5-30% of recommended), four tillage practices (CT-conventional tillage, NT-no tillage, CS-contour strip cropping, RC-residue cover) and three kinds of annual rainfall (deficit, normal, abundant) have been evaluated. Results from model simulations indicate that runoff and sediment yield were not affected due to change in fertilizer doses, but there was a significant positive correlation between nutrient losses and fertilizer application rates; Conservation tillage practices such as NT, CS and RC would reduce sediment and sediment-bound nutrient losses significantly, they have very little benefit on soluble nitrogen and phosphorus losses. This is primarily because the increased infiltration rates resulting from those practices leads to greater losses of subsurface and return flow in the watershed. In view of feasibility and efficiency, the combination of FL3 + NT was found to be the best scenario as the reductions of nutrient losses and sediment yield were about 40% and 45%, respectively. PMID:21528563

  16. Association of multiple-antibiotic-resistance profiles with point and nonpoint sources of Escherichia coli in Apalachicola Bay.

    PubMed

    Parveen, S; Murphree, R L; Edmiston, L; Kaspar, C W; Portier, K M; Tamplin, M L

    1997-07-01

    A total of 765 Escherichia coli isolates from point and nonpoint sources were collected from the Apalachicola National Estuarine Research Reserve, and their multiple-antibiotic-resistance (MAR) profiles were determined with 10 antibiotics. E. coli isolates from point sources showed significantly greater resistance (P < 0.05) to antibiotics and higher MAR indices than isolates from nonpoint sources. Specifically, 65 different resistance patterns were observed among point source isolates, compared to 32 among nonpoint source isolates. Examples of this contrast in MAR profiles included percentages of isolates with resistance to chlortetracycline-sulfathiazole of 33.7% and to chlortetracycline-penicillin G-sulfathiazole of 14.5% for point source isolates versus 15.4 and 1.7%, respectively, for nonpoint source isolates. MAR profile homology, based on coefficient similarity, showed that isolates from point sources were markedly more diverse than isolates from nonpoint sources. Seven clusters were observed among point source isolates, with a coefficient value of approximately 1.8. In contrast, only four clusters were observed among nonpoint source isolates. Covariance matrices of data displayed six very distinct foci representing nonpoint source E. coli isolates. Importantly, E. coli isolates obtained directly from human and animal feces also clustered among point and nonpoint sources, respectively. We conclude that E. coli MAR profiles were associated with point and nonpoint sources of pollution within Apalachicola Bay and that this method may be useful in facilitating management of other estuaries. PMID:9212410

  17. Simulation of nonpoint source contamination based on adaptive mesh refinement

    NASA Astrophysics Data System (ADS)

    Kourakos, G.; Harter, T.

    2014-12-01

    Contamination of groundwater aquifers from nonpoint sources is a worldwide problem. Typical agricultural groundwater basins receive contamination from a large array (in the order of ~10^5-6) of spatially and temporally heterogeneous sources such as fields, crops, dairies etc, while the received contaminants emerge at significantly uncertain time lags to a large array of discharge surfaces such as public supply, domestic and irrigation wells and streams. To support decision making in such complex regimes several approaches have been developed, which can be grouped into 3 categories: i) Index methods, ii)regression methods and iii) physically based methods. Among the three, physically based methods are considered more accurate, but at the cost of computational demand. In this work we present a physically based simulation framework which exploits the latest hardware and software developments to simulate large (>>1,000 km2) groundwater basins. First we simulate groundwater flow using a sufficiently detailed mesh to capture the spatial heterogeneity. To achieve optimal mesh quality we combine adaptive mesh refinement with the nonlinear solution for unconfined flow. Starting from a coarse grid the mesh is refined iteratively in the parts of the domain where the flow heterogeneity appears higher resulting in optimal grid. Secondly we simulate the nonpoint source pollution based on the detailed velocity field computed from the previous step. In our approach we use the streamline model where the 3D transport problem is decomposed into multiple 1D transport problems. The proposed framework is applied to simulate nonpoint source pollution in the Central Valley aquifer system, California.

  18. Cost-effectiveness and cost-benefit analysis of BMPs in controlling agricultural nonpoint source pollution in China based on the SWAT model.

    PubMed

    Liu, Ruimin; Zhang, Peipei; Wang, Xiujuan; Wang, Jiawei; Yu, Wenwen; Shen, Zhenyao

    2014-12-01

    Best management practices (BMPs) have been widely used in managing agricultural nonpoint source pollution (ANSP) at the watershed level. Most BMPs are related to land use, tillage management, and fertilizer levels. In total, seven BMP scenarios (Reforest1, Reforest2, No Tillage, Contour tillage, and fertilizer level 1-4) that are related to these three factors were estimated in this study. The objectives were to investigate the effectiveness and cost-benefit of these BMPs on ANSP reduction in a large tributary of the Three Gorges Reservoir (TGR) in China, which are based on the simulation results of the Soil and Water Assessment Tool (SWAT) model. The results indicated that reforestation was the most economically efficient of all BMPs, and its net benefits were up to CNY 4.36×10(7) years(-1) (about USD 7.08×10(6) years(-1)). Regarding tillage practices, no tillage practice was more environmentally friendly than other tillage practices, and contour tillage was more economically efficient. Reducing the local fertilizer level to 0.8-fold less than that of 2010 can yield a satisfactory environmental and economic efficiency. Reforestation and fertilizer management were more effective in reducing total phosphorus (TP), whereas tillage management was more effective in reducing total nitrogen (TN). When CNY 10,000 (about USD 162) was applied to reforestation, no tillage, contour tillage, and an 0.8-fold reduction in the fertilizer level, then annual TN load can be reduced by 0.08, 0.16, 0.11, and 0.04 t and annual TP load can be reduced by 0.04, 0.02, 0.01 and 0.03 t, respectively. The cost-benefit (CB) ratios of the BMPs were as follows: reforestation (207 %) > contour tillage (129 %) > no tillage (114 %) > fertilizer management (96 and 89 %). The most economical and effective BMPs can be designated as follows: BMP1 (returning arable land with slopes greater than 25° to forests and those lands with slopes of 15-25° to orchards), BMP2 (implementing no tillage

  19. Inferring non-point pollution from land cover analysis

    NASA Astrophysics Data System (ADS)

    Hyde, Richard F.

    Best Management Practices (BMP's) in farming were found to significantly reduce agricultural non-point water pollution in Central Indiana. Through the implementation of systems of conservation tillage practices and structural measures at the farm level, reductions in runoff were achieved, thereby minimizing erosion and subsequent sedimentation and pollution of the surface water system. These conclusions resulted from a three and one-half year study entitled, ``The Indiana Heartland Model Implementation Project'' administered by the Indiana Heartland Coordinating Commission, involving cooperation and coordination of farmers, citizens, and a multi-agency, multi-disciplinary team comprised of four universities and numerous governmental agencies. The U.S. Environmental Protection Agency funded research, while the U.S. Department of Agriculture provided cost share monies for BMP implementation. A comprehensive geographically encoded computer-aided data base was constructed which included information on land cover, elevation, slope, aspect, soils, etc. Land cover map files were compiled through remote sensing including Landsat MSS digital data and low altitude color infrared aerial photography sources. This digital data base was suited for spatial and statistical analyses and transferred easily as input to Purdue University's ANSWERS Model for further watershed assessment. The ANSWERS Model is a distributed deterministic model which simulates the monitored reaction of subwatersheds to actual storm events. Through this model inferences were made as to the expected water quality improvements, given BMP's were implemented at critical areas for erosion throughout both watersheds.

  20. Water quality indicators and the risk of illness at beaches with nonpoint sources of fecal contaminants

    EPA Science Inventory

    BACKGROUND: Indicator bacteria are a good predictor of illness at marine beaches that have point sources of pollution with human fecal content. Few studies have addressed the utility of indicator bacteria where nonpoint sources are the dominant fecal input. Extrapolating current ...

  1. Introducing nonpoint source transferable quotas in nitrogen trading: The effects of transaction costs and uncertainty.

    PubMed

    Zhou, Xiuru; Ye, Weili; Zhang, Bing

    2016-03-01

    Transaction costs and uncertainty are considered to be significant obstacles in the emissions trading market, especially for including nonpoint source in water quality trading. This study develops a nonlinear programming model to simulate how uncertainty and transaction costs affect the performance of point/nonpoint source (PS/NPS) water quality trading in the Lake Tai watershed, China. The results demonstrate that PS/NPS water quality trading is a highly cost-effective instrument for emissions abatement in the Lake Tai watershed, which can save 89.33% on pollution abatement costs compared to trading only between nonpoint sources. However, uncertainty can significantly reduce the cost-effectiveness by reducing trading volume. In addition, transaction costs from bargaining and decision making raise total pollution abatement costs directly and cause the offset system to deviate from the optimal state. While proper investment in monitoring and measuring of nonpoint emissions can decrease uncertainty and save on the total abatement costs. Finally, we show that the dispersed ownership of China's farmland will bring high uncertainty and transaction costs into the PS/NPS offset system, even if the pollution abatement cost is lower than for point sources. PMID:26724699

  2. Association of Fecal Indicator Bacteria with Human Viruses and Microbial Source Tracking Markers at Coastal Beaches Impacted by Nonpoint Source Pollution

    PubMed Central

    McQuaig, Shannon; Griffith, John

    2012-01-01

    Water quality was assessed at two marine beaches in California by measuring the concentrations of culturable fecal indicator bacteria (FIB) and by library-independent microbial source tracking (MST) methods targeting markers of human-associated microbes (human polyomavirus [HPyV] PCR and quantitative PCR, Methanobrevibacter smithii PCR, and Bacteroides sp. strain HF183 PCR) and a human pathogen (adenovirus by nested PCR). FIB levels periodically exceeded regulatory thresholds at Doheny and Avalon Beaches for enterococci (28.5% and 31.7% of samples, respectively) and fecal coliforms (20% and 5.8%, respectively). Adenoviruses were detected at four of five sites at Doheny Beach and were correlated with detection of HPyVs and human Bacteroides HF183; however, adenoviruses were not detected at Avalon Beach. The most frequently detected human source marker at both beaches was Bacteroides HF183, which was detected in 27% of samples. Correlations between FIBs and human markers were much more frequent at Doheny Beach than at Avalon Beach; e.g., adenovirus was correlated with HPyVs and HF183. Human sewage markers and adenoviruses were routinely detected in samples meeting FIB regulatory standards. The toolbox approach of FIB measurement coupled with analysis of several MST markers targeting human pathogens used here demonstrated that human sewage is at least partly responsible for the degradation of water quality, particularly at Doheny Beach, and resulted in a more definitive assessment of recreational water quality and human health risk than reliance on FIB concentrations alone could have provided. PMID:22773625

  3. Better Assessment Science Integrating Point and Nonpoint Sources

    EPA Science Inventory

    Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) is not a model per se, but is a multipurpose environmental decision support system for use by regional, state, and local agencies in performing watershed- and water-quality-based studies. BASI...

  4. NONPOINT SOURCE MODEL CALIBRATION IN HONEY CREEK WATERSHED

    EPA Science Inventory

    The U.S. EPA Non-Point Source Model has been applied and calibrated to a fairly large (187 sq. mi.) agricultural watershed in the Lake Erie Drainage basin of north central Ohio. Hydrologic and chemical routing algorithms have been developed. The model is evaluated for suitability...

  5. NONPOINT SOURCE - STREAM NUTRIENT LEVEL RELATIONSHIPS: A NATIONWIDE STUDY

    EPA Science Inventory

    National Eutrophication Survey (NES) data for a nationwide collection of 928 non-point source watersheds were studied for relationships between macro-drainage area characteristics (particularly land use) and nutrient levels in streams. Both the total and inorganic forms of phosph...

  6. 40 CFR 35.1605-4 - Nonpoint source.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Nonpoint source. 35.1605-4 Section 35.1605-4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Cooperative Agreements for Protecting and Restoring Publicly Owned...

  7. 40 CFR 35.1605-4 - Nonpoint source.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Nonpoint source. 35.1605-4 Section 35.1605-4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Cooperative Agreements for Protecting and Restoring Publicly Owned...

  8. 40 CFR 35.1605-4 - Nonpoint source.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Nonpoint source. 35.1605-4 Section 35.1605-4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Cooperative Agreements for Protecting and Restoring Publicly Owned...

  9. 40 CFR 35.1605-4 - Nonpoint source.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Nonpoint source. 35.1605-4 Section 35.1605-4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Cooperative Agreements for Protecting and Restoring Publicly Owned...

  10. 40 CFR 35.1605-4 - Nonpoint source.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Nonpoint source. 35.1605-4 Section 35.1605-4 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Cooperative Agreements for Protecting and Restoring Publicly Owned...

  11. Nonpoint-source nitrogen and phosphorus behavior and modeling in cold climate: a review.

    PubMed

    Han, Cheng-Wei; Xu, Shi-Guo; Liu, Jian-Wei; Lian, Jian-Jun

    2010-01-01

    Pollution from nonpoint-source (NPS) nitrogen (N) and phosphorus (P) are the main causes of eutrophication in lotic, lentic and coastal systems. The climate of cold regions might play an important role in disturbing environmental behavior of NPS N and P, influencing simulation of watershed scale hydrologic and nonpoint-source pollution models. The losses of NPS N and P increase in regions of cold climate. In cold seasons, accumulations of N and P are accelerated in soil with increasing fine root and aboveground biomass mortality, decreasing plant nutrient uptake, as well as freezing soil. N and P transformation is disturbed by soil frost and snow. Moreover, factors such as physical disruption of soil aggregates, pollutant accumulation in snowpack, and snow melting can all increase the NPS N and P losses to the waterbody. Therefore, NPS N and P in first flush are more serious in cold climate. All these effects, especially frozen soil and snowpack, make great challenges to watershed scale hydrologic and nonpoint-source pollution models simulation in cold climate. Model improvements of snowmelt runoff, nutrient losses in frozen soil, as well as N and P behavior have been initiated and will be continued to evaluate in terms of their performances and suitability with different scale, hydrologic and geologic conditions in the future. PMID:21076213

  12. Reducing future non-point source sediment and phosphorus loading under intensifying agricultural production in the Ethiopian highlands

    NASA Astrophysics Data System (ADS)

    Mogus, Mamaru; Schmitter, Petra; Tilahun, Seifu; Steenhuise, Tammo

    2016-04-01

    Intensification of agriculture will bring along non-point source pollution in the Ethiopian highlands resulting in eutrophication of lakes. The first signs of eutrophication have been observed already in Lake Tana. The lake it supports the lives of millions in the surrounding through fishing, tourism, transportation and hydropower.Presently, information on non-point source pollution is lacking in the Ethiopian highlands. There are few studies carried out in the highlands on the extent and the source areas of pollution, and models are not available for predicting sediment and phosphorus loading other than those developed for temperate climates. The objective of this chapter is to review existing non-point source studies, report on our findings of sediment and phosphorus sources that are related the non-point source pollution of Lake Tana and to present a non-point source model for the Ethiopian highland based on the Parameter Efficient Semi-distributed Watershed Hydrology Model (PED-WHM).In our research we have found that the saturation excess runoff from valley bottoms and from degraded lands are prevalent in the Ethiopia highlands. The periodically runoff source areas are also the sources for the non-point source pollution and by concentrating best management practices in these source areas we expect that we can reduce pollution without affecting the profitability of the existing farms. The water balance component of the non-point source model has been performing well in predicting both the discharge and the location of the runoff source areas. Sediment and phosphorus prediction models have been developed and are currently being tested for the 7km2Awramba watershed and the 1350 km2Gumara basin. Initial results indicate that 11.2 ton/ha/year sediment load and an accumulation rate of 17.3 mg/kg/year of dissolved phosphorus from Gumara watershed joining the lake. By developing best management practices at this time before non-point source pollution is rampant and

  13. [Ecosystem service and economic valuation in the upper reaches of Xin' an River, Anhui, China for mitigating phosphorus nonpoint source pollution].

    PubMed

    He, Fang; Wu, Nan; Fang, Xiang-long; Gao, Ji-xi; Zhou, Xiao-tie; Feng, Chao-yang

    2015-04-01

    A model of phosphorus purification in a watershed was established based on the export coefficient and purification index of phosphorus in different types of land cover. The model was employed to simulate the economic value of the ecosystem service with the expected water quality standard and marginal cost of pollutant purification of the upper reaches of Xin' an River of Anhui, China. The results revealed that from 2000 to 2010, some farmland outside the Tunxi, Jixi, Shexian, Yixian and Xiuning was converted to built-up land. The total amount of phosphorus exported to the upper Xin' an River decreased a little, and the main source of phosphorus pollution was farmland and built-up land. More than half of the exported phosphorus was efficiently purified by different types of land cover via flow accumulation. The pattern of purification and export of highly concentrated phosphorus showed the same trend which occurred in the northern part of the watershed including the Yangzhi River, Fengle River and Hengjiang River. Forestland and grassland did not efficiently purify phosphorus in the watershed owing to the irrational distribution of existing land cover. The total service value was 3.80 and 3.31 million Yuan in 2000 and 2010, respectively. PMID:26259471

  14. Inferring non-point pollution from land cover analysis

    SciTech Connect

    Hyde, R.F.

    1982-01-01

    The effectiveness of the agricultural Best Management Practices (BMP) used in the 3 1/2-year Indiana Heartland Model Implementation Project in controlling non-point water pollution is assessed by coordinating data from Landsat, low-altitude IR aerial photography, and field observations, using computer mapping and analysis techniques. Landsat images were found to identify urban areas, forest, and water, but to be of only limited value in differentiating grassland, pasture, and cropland. Aerial photography distinguished grassland, pasture, and cropland, but not specific crops or tillage practices. A significant correlation between subwatershed crop cover and fish populations is found, implying that measures of cropland area can be used to estimate water quality, at least insofar as it affects fish well-being. In situ studies showed that the BMP reduced erosion, sedimentation of streams, and pollution. It is suggested that future BMP programs be targeted at areas of maximum soil-erosion potential, which could be identified cost-effectively by remote-sensing techniques.

  15. [Transformation of Non-point Source Soluble Nitrogen in Simulated Drainage Ditch].

    PubMed

    Li, Qiang-kun; Song, Chang-ji; Hu, Ya-wei; Peng, Cong; Ma, Qiang; Jiang, Zheng-xi; Ju, Yi-rheng

    2016-02-15

    The drainage ditch has a compound ecosystem structure consisting of water, sediment and plants. Migration and transformation of the non-point source solute is important to study interception, control and management of agricultural non-point source pollution in the drainage ditch. Based on the experiment on static simulation of drainage ditches, the article used typical non-point source soluble nitrogen as an example to analyze the changing process of nitrogen content in water, sediment and reeds, and to study the effects of the sediment adsorption and desorption, reeds growth and death in different periods on nitrogen concentration in water. The article discussed nitrogen migration in water-sediment-reeds compound ecosystem and its influence on nitrogen concentration in water. The results showed that both adsorption and desorption in sediment and absorption and assimilation of reeds growth had effect on nitrogen concentration in water. The effect before October was reducing the nitrogen concentration in water, which was the process of nitrogen purification in water. After October, the nitrogen concentration in water increased and made it easy to form secondary nitrogen pollution. Meanwhile, the migration in the water-sediment-seeds ecosystem in simulated drainage ditch had close ties, any migration and transformation of nitrogen in a single medium or between different mediums would cause adjustment of nitrogen concentration in water. PMID:27363139

  16. [Purification capacity of ditch wetland to agricultural non-point pollutants].

    PubMed

    Jiang, Cui-ling; Cui, Guang-bo; Fan, Xiao-qiu; Zhang, Yi-bing

    2004-03-01

    Ditch wetlands have the capacity to remove and purify non-point pollutants from agricultural drainage by sediment retention, plant absorption and microorganism decomposition. Phragmites communis and Zizania latifolia are two main kinds of plants growing naturally in ditch wetlands in the lower reaches of the Yangtze River. They can absorb N and P efficiently, which is the main mechanism of non-point source pollutants purification by wetlands. The harvest of Phragmites communis and Zizania latifolia will take away 463-515 kg/hm2 of N and 127-149 kg/hm2 of P each year, it equal to N and P discharged from 2.3-3.2 hm2 and 1.3-3.0 hm2 of fields respectively in this area. The absorption and decomposition capacity of Zizania latifolia wetland is higher than Phragmites communis wetland. After harvest of plants, wetlands are uncovered to sunlight and oxygen that speeds the transportation and decomposition of nutrients. The amount of organic matters, TN and TP are higher in sediment of harvested area than in that of control. Therefore, seasonal harvest of plants is an efficient measure for wetlands to purify nutrients and alleviate eutrophication of lakes. PMID:15202249

  17. A spatial model to aggregate point-source and nonpoint-source water-quality data for large areas

    USGS Publications Warehouse

    White, D.A.; Smith, R.A.; Price, C.V.; Alexander, R.B.; Robinson, K.W.

    1992-01-01

    More objective and consistent methods are needed to assess water quality for large areas. A spatial model, one that capitalizes on the topologic relationships among spatial entities, to aggregate pollution sources from upstream drainage areas is described that can be implemented on land surfaces having heterogeneous water-pollution effects. An infrastructure of stream networks and drainage basins, derived from 1:250,000-scale digital-elevation models, define the hydrologic system in this spatial model. The spatial relationships between point- and nonpoint pollution sources and measurement locations are referenced to the hydrologic infrastructure with the aid of a geographic information system. A maximum-branching algorithm has been developed to simulate the effects of distance from a pollutant source to an arbitrary downstream location, a function traditionally employed in deterministic water quality models. ?? 1992.

  18. Polluted dust derived from long-range transport as a major end member of urban aerosols and its implication of non-point pollution in northern China.

    PubMed

    Yan, Y; Sun, Y B; Weiss, D; Liang, L J; Chen, H Y

    2015-02-15

    The contribution of polluted dust transported from local and distal sources remains poorly constrained due to their similar geophysical and geochemical properties. We sampled aerosols in three cities in northern China (Xi'an, Beijing, Xifeng) during the spring of 2009 to determine dust flux, magnetic susceptibility and elemental concentrations. Combining dust fluxes with wind speed and regional visibility records enabled to differentiate between dust transported from long range and derived from local sources, while the combination of magnetic susceptibility and enrichment factors (EF) of heavy metals (Pb, Zn) allowed to distinguish natural aerosols from polluted ones. Our results indicate that polluted dust from long-range transport became a major end member of urban dust aerosols. Human settlements as its potential sources were confirmed by a pollutant enriched regional dust event originating from populated areas to the south as inferred by back trajectory modeling, implying their non-point source nature of dust pollution. PMID:25433377

  19. Agricultural land use and best management practices to control nonpoint water pollution.

    PubMed

    Ripa, Maria Nicoletta; Leone, Antonio; Garnier, Monica; Lo Porto, Antonio

    2006-08-01

    In recent years, improvements in point-source depuration technologies have highlighted the problems regarding agricultural nonpoint (diffuse) sources, and this issue has become highly relevant from the environmental point of view. The considerable extension of the areas responsible for this kind of pollution, together with the scarcity of funds available to local managers, make minimizing the impacts of nonpoint sources on a whole basin a virtually impossible task. This article presents the results of a study intended to pinpoint those agricultural areas, within a basin, that contribute most to water pollution, so that operations aimed at preventing and/or reducing this kind of pollution can be focused on them. With this aim, an innovative approach is presented that integrates a field-scale management model, a simple regression model, and a geographic information system (GIS). The Lake Vico basin, where recent studies highlighted a considerable increase in the trophic state, mainly caused by phosphorus (P) compounds deriving principally from the intensive cultivation of hazelnut trees in the lake basin, was chosen as the study site. Using the management model Groundwater Loading Effects of Agricultural Management Systems (GLEAMS), the consequences, in terms of sediment yield and phosphorus export, of hazelnut tree cultivation were estimated on different areas of the basin with and without the application of a best management practice (BMP) that consists of growing meadow under the trees. The GLEAMS results were successively extended to basin scale thanks to the application of a purposely designed regression model and of a GIS. The main conclusions can be summarized as follows: The effectiveness of the above-mentioned BMP is always greater for erosion reduction than for particulate P reduction, whatever the slope value considered; moreover, the effectiveness with reference to both particulate P and sediment yield production decreases as the slope increases. The

  20. Agricultural Land Use and Best Management Practices to Control Nonpoint Water Pollution

    NASA Astrophysics Data System (ADS)

    Ripa, Maria Nicoletta; Leone, Antonio; Garnier, Monica; Porto, Antonio Lo

    2006-08-01

    In recent years, improvements in point-source depuration technologies have highlighted the problems regarding agricultural nonpoint (diffuse) sources, and this issue has become highly relevant from the environmental point of view. The considerable extension of the areas responsible for this kind of pollution, together with the scarcity of funds available to local managers, make minimizing the impacts of nonpoint sources on a whole basin a virtually impossible task. This article presents the results of a study intended to pinpoint those agricultural areas, within a basin, that contribute most to water pollution, so that operations aimed at preventing and/or reducing this kind of pollution can be focused on them. With this aim, an innovative approach is presented that integrates a field-scale management model, a simple regression model, and a geographic information system (GIS). The Lake Vico basin, where recent studies highlighted a considerable increase in the trophic state, mainly caused by phosphorus (P) compounds deriving principally from the intensive cultivation of hazelnut trees in the lake basin, was chosen as the study site. Using the management model Groundwater Loading Effects of Agricultural Management Systems (GLEAMS), the consequences, in terms of sediment yield and phosphorus export, of hazelnut tree cultivation were estimated on different areas of the basin with and without the application of a best management practice (BMP) that consists of growing meadow under the trees. The GLEAMS results were successively extended to basin scale thanks to the application of a purposely designed regression model and of a GIS. The main conclusions can be summarized as follows: The effectiveness of the above-mentioned BMP is always greater for erosion reduction than for particulate P reduction, whatever the slope value considered; moreover, the effectiveness with reference to both particulate P and sediment yield production decreases as the slope increases. The

  1. [Multiple time scales analysis of spatial differentiation characteristics of non-point source nitrogen loss within watershed].

    PubMed

    Liu, Mei-bing; Chen, Xing-wei; Chen, Ying

    2015-07-01

    Identification of the critical source areas of non-point source pollution is an important means to control the non-point source pollution within the watershed. In order to further reveal the impact of multiple time scales on the spatial differentiation characteristics of non-point source nitrogen loss, a SWAT model of Shanmei Reservoir watershed was developed. Based on the simulation of total nitrogen (TN) loss intensity of all 38 subbasins, spatial distribution characteristics of nitrogen loss and critical source areas were analyzed at three time scales of yearly average, monthly average and rainstorms flood process, respectively. Furthermore, multiple linear correlation analysis was conducted to analyze the contribution of natural environment and anthropogenic disturbance on nitrogen loss. The results showed that there were significant spatial differences of TN loss in Shanmei Reservoir watershed at different time scales, and the spatial differentiation degree of nitrogen loss was in the order of monthly average > yearly average > rainstorms flood process. TN loss load mainly came from upland Taoxi subbasin, which was identified as the critical source area. At different time scales, land use types (such as farmland and forest) were always the dominant factor affecting the spatial distribution of nitrogen loss, while the effect of precipitation and runoff on the nitrogen loss was only taken in no fertilization month and several processes of storm flood at no fertilization date. This was mainly due to the significant spatial variation of land use and fertilization, as well as the low spatial variability of precipitation and runoff. PMID:26710649

  2. Effects of land-use changes and stormflow-detention basins on flooding and nonpoint-source pollution, in Irondequoit Creek basin, Monroe and Ontario counties, New York--application of a precipitation-runoff model

    USGS Publications Warehouse

    Coon, William F.; Johnson, Mark S.

    2005-01-01

    Urbanization of the 150-square-mile Irondequoit Creek basin in Monroe and Ontario Counties, N.Y., continues to spread southward and eastward from the City of Rochester, on the shore of Lake Ontario. Conversion of forested land to other uses over the past 40 years has increased to the extent that more than 50 percent of the basin is now developed. This expansion has increased flooding and impaired stream-water quality in the northern (downstream) half of the basin. A precipitation-runoff model of the Irondequoit Creek basin was developed with the model code HSPF (Hydrological Simulation Program--FORTRAN) to simulate the effects of land-use changes and stormflow-detention basins on flooding and nonpoint-source pollution on the basin. Model performance was evaluated through a combination of graphical comparisons and statistical tests, and indicated 'very good' agreement (mean error less than 10 percent) between observed and simulated daily and monthly streamflows, between observed and simulated monthly water temperatures, and between observed total suspended solids loads and simulated sediment loads. Agreement between monthly observed and simulated nutrient loads was 'very good' (mean error less than 15 percent) or 'good' (mean error between 15 and 25 percent). Results of model simulations indicated that peak flows and loads of sediment and total phosphorus would increase in a rural subbasin, where 10 percent of the basin was converted from forest and grassland to pervious and impervious developed areas. Subsequent simulation of a stormflow-detention basin at the mouth of this subbasin indicated that peak flows and constituent loads would decrease below those that were generated by the land-use-change scenario, and, in some cases, below those that were simulated by the original land-use scenario. Other results from model simulations of peak flows over a 30-year period (1970-2000), with and without simulation of 50-percent flow reductions at one existing and nine

  3. Application of Potential Non-Point Pollution Index For An Urban Watershed: Istanbul, Kucukcekmece Lagoon

    NASA Astrophysics Data System (ADS)

    Musaoglu, N.; Dikerler, T.; Seker, D. Z.; Ustun, B.

    2011-12-01

    Istanbul is a major city with more than 15 million population and limited water resources. Besides, its urbanized area has been rapidly expanding for more than 30 years. Küçükçekmece Lagoon, as a potential RAMSAR site with its rich natural diversity and housing asset for birds, has been suffering from urbanization and industrial stress. With Sazlidere Dam constructed on the Lagoon's most important creek which supplies fresh water, Küçükçekmece Basin has almost 600 km2 wide area. Due to dam operation which cuts fresh water input down, water quality of the Küçükçekmece Lagoon has been deteriorating, as well as other antropogenic impacts. Potential non-point pollution index (or PNPI) is based on land use, soil and topographic data and aims to highlight the potentially polluting areas in a watershed. Denoting those areas, PNPI puts an assessment of the pressure exerted on the water bodies by different land uses. This index calculates different layers in order to represent run-off, land cover effect, and the distance of each polluting source (or pixels) in the study area. By the multiplication of those layers under GIS, a new data layer is produced showing the polluting potential of each pixel on the study area. For by Küçükçekmece Basin, Landsat ETM satellite images have been taken and its land use produced by unsupervised classification. Using this updated data, land use - land cover indicator has been calculated for the basin. Topography is another fact that is needed to produce both run-off indicator and distance indicator and it is generated by elevation data with 5m resolution. By integrating these indicator layers, PNPI analysis layer has been produced for Küçükçekmece Lagoon watershed.

  4. Tracking Nonpoint Source Nitrogen and Carbon in Watersheds of Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Kaushal, S.; Pennino, M. J.; Duan, S.; Blomquist, J.

    2012-12-01

    Humans have altered nitrogen and carbon cycles in rivers regionally with important impacts on coastal ecosystems. Nonpoint source nitrogen pollution is a leading contributor to coastal eutrophication and hypoxia. Shifts in sources of carbon impact downstream ecosystem metabolism and fate and transport of contaminants in coastal zones. We used a combination of stable isotopes and optical tracers to investigate fate and transport of nitrogen and carbon sources in tributaries of the largest estuary in the U.S., the Chesapeake Bay. We analyzed isotopic composition of water samples from major tributaries including the Potomac River, Susquehanna River, Patuxent River, and Choptank River during routine and storm event sampling over multiple years. A positive correlation between δ15N-NO3- and δ18O-NO3- in the Potomac River above Washington D.C. suggested denitrification or biological uptake in the watershed was removing agriculturally-derived N during summer months. In contrast, the Patuxent River in Maryland showed elevated δ15N-NO3- (5 - 12 per mil) with no relationship to δ18O-NO3- suggesting the importance of wastewater sources. From the perspective of carbon sources, there were distinct isotopic values of the δ13C-POM of particulate organic matter and fluorescence excitation emission matrices (EEMS) for rivers influenced by their dominant watershed land use. EEMS showed that there were increases in the humic and fulvic fractions of dissolved organic matter during spring floods, particularly in the Potomac River. Stable isotopic values of δ13C-POM also showed rapid depletion suggesting terrestrial carbon "pulses" in the Potomac River each spring. The δ15N-POM peaked to 10 - 15 per mil each spring suggested a potential manure source or result of biological processing within the watershed. Overall, there were considerable changes in sources and transformations of nitrogen and carbon that varied across rivers and that contribute to nitrogen and carbon loads

  5. Mapping hazard from urban non-point pollution: a screening model to support sustainable urban drainage planning.

    PubMed

    Mitchell, Gordon

    2005-01-01

    Non-point sources of pollution are difficult to identify and control, and are one of the main reasons that urban rivers fail to reach the water quality objectives set for them. Whilst sustainable drainage systems (SuDS) are available to help combat this diffuse pollution, they are mostly installed in areas of new urban development. However, SuDS must also be installed in existing built areas if diffuse loadings are to be reduced. Advice on where best to locate SuDS within existing built areas is limited, hence a semi-distributed stochastic GIS-model was developed to map small-area basin-wide loadings of 18 key stormwater pollutants. Load maps are combined with information on surface water quality objectives to permit mapping of diffuse pollution hazard to beneficial uses of receiving waters. The model thus aids SuDS planning and strategic management of urban diffuse pollution. The identification of diffuse emission 'hot spots' within a water quality objectives framework is consistent with the 'combined' (risk assessment) approach to pollution control advocated by the EU Water Framework Directive. PMID:15572076

  6. Nonpoint sources of volatile organic compounds in urban areas - Relative importance of land surfaces and air

    USGS Publications Warehouse

    Lopes, T.J.; Bender, D.A.

    1998-01-01

    Volatile organic compounds (VOCs) commonly detected in urban waters across the United States include gasoline-related compounds (e.g. toluene, xylene) and chlorinated compounds (e.g. chloroform, tetrachloroethane [PCE], trichloroethene [TCE]). Statistical analysis of observational data and results of modeling the partitioning of VOCs between air and water suggest that urban land surfaces are the primary nonpoint source of most VOCs. Urban air is a secondary nonpoint source, but could be an important source of the gasoline oxygenate methyl-tert butyl ether (MTBE). Surface waters in urban areas would most effectively be protected by controlling land-surface sources.

  7. Quantifying the uncertainty of nonpoint source attribution in distributed water quality models: A Bayesian assessment of SWAT's sediment export predictions

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    Spatially distributed nonpoint source watershed models are essential tools to estimate the magnitude and sources of diffuse pollution. However, little work has been undertaken to understand the sources and ramifications of the uncertainty involved in their use. In this study we conduct the first Bayesian uncertainty analysis of the water quality components of the SWAT model, one of the most commonly used distributed nonpoint source models. Working in Southern Ontario, we apply three Bayesian configurations for calibrating SWAT to Redhill Creek, an urban catchment, and Grindstone Creek, an agricultural one. We answer four interrelated questions: can SWAT determine suspended sediment sources with confidence when end of basin data is used for calibration? How does uncertainty propagate from the discharge submodel to the suspended sediment submodels? Do the estimated sediment sources vary when different calibration approaches are used? Can we combine the knowledge gained from different calibration approaches? We show that: (i) despite reasonable fit at the basin outlet, the simulated sediment sources are subject to uncertainty sufficient to undermine the typical approach of reliance on a single, best fit simulation; (ii) more than a third of the uncertainty of sediment load predictions may stem from the discharge submodel; (iii) estimated sediment sources do vary significantly across the three statistical configurations of model calibration despite end-of-basin predictions being virtually identical; and (iv) Bayesian model averaging is an approach that can synthesize predictions when a number of adequate distributed models make divergent source apportionments. We conclude with recommendations for future research to reduce the uncertainty encountered when using distributed nonpoint source models for source apportionment.

  8. Nonpoint sources as external threats to coastal water quality: lessons from Park Service experience

    USGS Publications Warehouse

    Burroughs, R.H.

    1993-01-01

    Program design for nonpoint source control was considered through an analogous problem, external threats to national parks. Nonpoint sources are diffuse land activities that degrade water quality, and recent federal legislation seeks to limit them in coastal areas. External threats occur outside a park boundary but affect the purposes for, or resources within, a park. They have been subject to federal management for many decades. Nonpoint sources are a class of external threat. Therefore, programs to limit them should consider techniques used in part protection. These park techniques include 'hard approaches', which rely on power, usually through legal devices, and 'soft approaches', which utilize shared values and objectives. A linked approach, as exemplified at the Cape Cod National Seashore, appears most promising. In a linked approach, if a soft approach fails, the manager of the protected unit is empowered to take an alternative hard action to protect the resource.

  9. Identifying non-point source critical source areas based on multi-factors at a basin scale with SWAT

    NASA Astrophysics Data System (ADS)

    Liu, Ruimin; Xu, Fei; Zhang, Peipei; Yu, Wenwen; Men, Cong

    2016-02-01

    The identification of critical source areas (CSAs) is a precondition for non-point source (NPS) pollution control at a basin scale, especially in areas with limited resources. Based on the Soil and Water Assessment Tool (SWAT), nutrient loads coupled with population density and water quality requirements are regarded as multi-factors for CSAs identification in Xiangxi river watershed, the first tributary of the Yangtze River. The results based on the calibrated model found that the subbasins heavily and seriously polluted by nutrient loads were different from the subbasins identified as CSAs, demonstrating integrating socio-economic factors like population density and water quality requirements to identify CSAs is of much necessity. The CSAs occupied 19.7% of the total subbasins, and accounted for 53% total nitrogen loads, 54% total phosphorus loads and 36% of the total population. Considering the model calibration and validation will take a long time as well as data deficiency in some subbasins, the influence of uncalibrated SWAT on CSAs identifications was discussed. The comparative results between CSAs identification with calibrated and uncalibrated SWAT model revealed that model calibration had little effect on nutrients distribution and CSAs locations in the study area. Uncalibrated SWAT model may be applied when the research objective is less related to model calibration. The results will be greatly effective for CSAs identification and NPS pollution control at a basin scale.

  10. Analysis of lake-bottom sediment to estimate historical nonpoint-source phosphorus loads

    USGS Publications Warehouse

    Juracek, K.E.

    1998-01-01

    Bottom sediment in Hillsdale Lake, Kansas, was analyzed to estimate the annual load of total phosphorus deposited in the lake from nonpoint sources. Topographic, bathymetric, and sediment-core data were used to estimate the total mass of phosphorus in the lake-bottom sediment. Available streamflow and water-quality data were used to compute the mean annual mass of phosphorus (dissolved plus suspended) exiting the lake. The mean annual load of phosphorus added to the lake from point sources was estimated from previous studies. A simple mass balance then was used to compute the mean annual load of phosphorus from nonpoint sources. The total mass of phosphorus in the lake-bottom sediment was estimated to be 924,000 kg, with a mean annual load of 62,000 kg. The mean annual mass of phosphorus exiting in the lake outflow was estimated to be about 8,000 kg. The mean annual loads of phosphorus added to the lake from point and nonpoint sources were estimated to be 5,000 and 65,000 kg, respectively. Thus, the contribution to the total mean annual phosphorus load in Hillsdale Lake is about 7 percent from point sources and about 93 percent from nonpoint sources.

  11. BEST MANAGEMENT PRACTICES FOR THE CONTROL OF NUTRIENTS FROM URBAN NONPOINT SOURCES

    EPA Science Inventory

    While the costs and benefits associated with the point source control of nutrients are relatively well defined, considerable uncertainties remain in the efficiency and long-term costs associated with the best management practices (BMPs) used to redcuce loads from nonpoint and dif...

  12. U. S. EPA Nonpoint-Source Information Exchange Computer Bulletin Board System (BBS). User's manual

    SciTech Connect

    Not Available

    1992-01-01

    The Nonpoint Source (NPS) Information Exchange Bulletin Board System (BBS) will provide state and local agencies, private organizations, businesses, and concerned individuals with timely, relevant NPS information, a forum for open discussion, and the ability to exchange computer text and program files.

  13. HYDROLOGY AND SEDIMENT MODELING USING THE BASINS NON-POINT SOURCE MODEL

    EPA Science Inventory

    The Non-Point Source Model (Hydrologic Simulation Program-Fortran, or HSPF) within the EPA Office of Water's BASINS watershed modeling system was used to simulate streamflow and total suspended solids within Contentnea Creek, North Carolina, which is a tributary of the Neuse Rive...

  14. EVALUATING POINT-NONPOINT SOURCE WATER QUALITY TRADING IN A RARITAN RIVER BASIN SUB-WATERSHED

    EPA Science Inventory

    This project addresses water quality issues in the Raritan River Basin of New Jersey. It will build upon an existing study that determined the technical feasibility of implementing a point-nonpoint source water quality trading program in the Basin. Water quality trading is ...

  15. An assessment of nonpoint-source discharges, streamflow, and water quality in Onion River, Wisconsin

    USGS Publications Warehouse

    Field, S.J.; Lidwin, R.A.

    1984-01-01

    Nutrient yields and loading rates were highest downstream of Hingham. Nonpoint-source contribution of phosphorus amounted to 362 pounds per square mile downstream of Hingham compared to 272 pounds per square mile upstream of Hingham in the 19

  16. NON-POINT SOURCE--STREAM NUTRIENT LEVEL RELATIONSHIPS: A NATIONWIDE STUDY. SUPPLEMENT 1: NUTRIENT MAP RELIABILITY

    EPA Science Inventory

    The National Eutrophication Survey (NES) national maps of non-point source nitrogen and phosphorus concentrations in streams were evaluated for applicability and reliability. Interpretations on these maps which were based on data from 928 sampling sites associated with non-point ...

  17. Nonpoint-Source Agricultural Hazard Index: A Case Study of the Province of Cremona, Italy

    NASA Astrophysics Data System (ADS)

    Trevisan, Marco; Padovani, Laura; Capri, Ettore

    2000-11-01

    This paper reports the results of a study aimed at the evaluation of the hazard level of farming activities in the province of Cremona, Italy, with particular reference to groundwater. The applied methodology employs a parametric approach based on the definition of potential hazard indexes (nonpoint-source agricultural hazard indexes, NPSAHI). Two categories of parameters were considered: the hazard factors (HF), which represent all farming activities that cause or might cause an impact on groundwater (use of fertilizers and pesticides, application of livestock and poultry manure, food industry wastewater, and urban sludge), and the control factors (CF), which adapt the hazard factor to the characteristics of the site (geographical location, slope, agronomic practices, and type of irrigation). The hazard index (HI) can be calculated multiplying the hazard factors by the control factors and, finally, the NPSAHI are obtained dividing HI into classes on a percentile basis using a scale ranging from 1 to 10. Organization, processing, and display of all data layers were performed using the geographical information system (GIS) ArcView and its Spatial Analyst extension. Results show that the potential hazard of groundwater pollution by farming activities in the province of Cremona falls mainly in the fifth class (very low hazard).

  18. Combined Bayesian statistics and load duration curve method for bacteria nonpoint source loading estimation.

    PubMed

    Shen, Jian; Zhao, Yuan

    2010-01-01

    Nonpoint source load estimation is an essential part of the development of the bacterial total maximum daily load (TMDL) mandated by the Clean Water Act. However, the currently widely used watershed-receiving water modeling approach is usually associated with a high level of uncertainty and requires long-term observational data and intensive training effort. The load duration curve (LDC) method recommended by the EPA provides a simpler way to estimate bacteria loading. This method, however, does not take into consideration the specific fate and transport mechanisms of the pollutant and cannot address the uncertainty. In this study, a Bayesian statistical approach is applied to the Escherichia coli TMDL development of a stream on the Eastern Shore of Virginia to inversely estimate watershed bacteria loads from the in-stream monitoring data. The mechanism of bacteria transport is incorporated. The effects of temperature, bottom slope, and flow on allowable and existing load calculations are discussed. The uncertainties associated with load estimation are also fully described. Our method combines the merits of LDC, mechanistic modeling, and Bayesian statistics, while overcoming some of the shortcomings associated with these methods. It is a cost-effective tool for bacteria TMDL development and can be modified and applied to multi-segment streams as well. PMID:19781737

  19. Evaluating potential non-point source loading of PAHs from contaminated soils: a fugacity-based modeling approach.

    PubMed

    Luo, Xiaolin; Zheng, Yi; Lin, Zhongrong; Wu, Bin; Han, Feng; Tian, Yong; Zhang, Wei; Wang, Xuejun

    2015-01-01

    Soils contaminated by Polycyclic Aromatic Hydrocarbons (PAHs) are subject to significant non-point source (NPS) pollution during rainfall events. Recent studies revealed that the classic enrichment ratio (ER) approach may not be applicable to PAHs. This study developed a model to estimate the ER of PAHs which innovatively applies the fugacity concept. The ER model has been validated with experimental data, which suggested that the transport of PAHs not only depends on their physicochemical properties, but on the sediment composition and how the composition evolves during the event. The modeling uncertainty was systematically examined, and found to be highly compound-dependent. Based on the ER model, a strategy was proposed to practically evaluate the potential NPS loading of PAHs in watersheds with heterogeneous soils. The study results have important implications to modeling and managing the NPS pollution of PAHs (or other chemicals alike) at a watershed scale. PMID:25282126

  20. NASA-Modified Precipitation Products to Improve EPA Nonpoint Source Water Quality Modeling for the Chesapeake Bay

    NASA Technical Reports Server (NTRS)

    Nigro, Joseph; Toll, David; Partington, Ed; Ni-Meister, Wenge; Lee, Shihyan; Gutierrez-Magness, Angelica; Engman, Ted; Arsenault, Kristi

    2010-01-01

    The Environmental Protection Agency (EPA) has estimated that over 20,000 water bodies within the United States do not meet water quality standards. Ninety percent of the impairments are typically caused by nonpoint sources. One of the regulations in the Clean Water Act of 1972 requires States to monitor the Total Maximum Daily Load (TMDL), or the amount of pollution that can be carried by a water body before it is determined to be "polluted", for any watershed in the U.S.. In response to this mandate, the EPA developed Better Assessment Science Integrating Nonpoint Sources (BASINS) as a Decision Support Tool (DST) for assessing pollution and to guide the decision making process for improving water quality. One of the models in BASINS, the Hydrological Simulation Program -- Fortran (HSPF), computes daily stream flow rates and pollutant concentration at each basin outlet. By design, precipitation and other meteorological data from weather stations serve as standard model input. In practice, these stations may be unable to capture the spatial heterogeneity of precipitation events especially if they are few and far between. An attempt was made to resolve this issue by substituting station data with NASA modified/NOAA precipitation data. Using these data within HSPF, stream flow was calculated for seven watersheds in the Chesapeake Bay Basin during low flow periods, convective storm periods, and annual flows. In almost every case, the modeling performance of HSPF increased when using the NASA-modified precipitation data, resulting in better stream flow statistics and, ultimately, in improved water quality assessment.

  1. Three studies using Ceriodaphnia to detect nonpoint sources of metals from mine drainage

    USGS Publications Warehouse

    Nimmo, Del Wayne R.; Dodson, Max H.; Davies, Patrick H.; Greene, Joseph C.; Kerr, Mark A.

    1990-01-01

    Since its introduction, Ceriodaphnia dubia, a small planktonic daphnid, has been widely used for biomonitoring point source discharges. This species was also used to determine nonpoint sources of metals and related contaminants in three trout streams in the west where mining activities have been widespread. Along Chalk Creek, Colo., specific tailings (and impacted tributaries) were sources of metals toxic to fish using the water in a hatchery. At stations below extensive mine tailings in the upper Clark Fork River, Mont., drainage was acutely and chronically toxic to daphnids and paralleled reduced or nonexistent populations of trout. In Whitewood Creek, S. Dak., reduced toxicity below a gold mine portended that fish could live in the stream segment previously impaired by the mine. Toxicity downstream revealed a previously unknown nonpoint source of chromium.

  2. Watershed Characteristics and Land Management in the Nonpoint-Source Evaluation Monitoring Watersheds in Wisconsin

    USGS Publications Warehouse

    Rappold, K.F.; Wierl, J.A.; Amerson, F.U.

    1997-01-01

    In 1992, the Wisconsin Department of Natural Resources, in cooperation with the U.S. Geological Survey, began a land-use inventory to identify sources of contaminants and track the land-management changes for eight evaluation monitoring watersheds in Wisconsin. An important component of the land-use inventory has been developing descriptions and preliminary assessments for the eight watersheds. These descriptions establish a baseline for future data analysis. The watershed descriptions include sections on location, reference watersheds, climate, land use, soils and topography, and surface-water resources. The land-management descriptions include sections on objectives, sources of nonpoint contamination and goals of contaminant reduction, and implementation of best-management practices. This information was compiled primarily from the nonpoint-source control plans, county soil surveys, farm conservation plans, Federal and State agency data reports, and data collected through the land-use inventory.

  3. Better assessment science integrating point and nonpoint sources (BASINS), version 2.0. User`s manual

    SciTech Connect

    Lahlou, M.; Shoemaker, L.; Choudhury, S.; Elmer, R.; Hu, A.

    1998-11-01

    BASINS is a multipurpose environmental analysis system for use by regional, state, and local agencies in performing watershed- and water-quality-based studies. BASINS comprises a suite of interrelated components for performing the various aspects of environmental analysis. The six components include (1) nationally derived databases with Data Extraction tools and Project Builders; (2) assessment tools (TARGET, ASSESS, and Data Mining) that address large- and small-scale characterization needs; (3) utilites to facilitate organizing and evaluating data, including Watershed Delineation, Import, Land Use Reclassfication, and DEM Reclassification; (4) Watershed Characterization Reports that facilitate compilation and output of information on selected watersheds; (5) water quality models including TOXIROUTE and QUAL2E; and (6) the Nonpoint Source Model (NPSM) and postprocessor, which provide integrated assessment of watershed loading and transport, The assessment component, working under the GIS umbrella, allows users to quickly evaluate selected areas, organize information, and display results. The modeling component module allows users to examine the impacts of pollutant loadings from point and nonpoint sources.

  4. Fine-scale chemical exposure differs in point and nonpoint source plumes.

    PubMed

    Lahman, Sara E; Moore, Paul A

    2015-05-01

    Increasing influxes of anthropogenic chemicals into aquatic ecosystems has led to growing global concern surrounding human and ecosystem health. As more freshwater systems are deemed not potable or usable for agricultural purposes, more attention is being paid to remediation and mitigation efforts. Predicting and preventing the impacts of the chemical inputs first requires a thorough understanding of the spatio-temporal distribution of chemical plumes in natural habitats. Plume dispersion is intimately tied to fluid mechanics; therefore, alterations in the way that chemical plumes are introduced to habitats can have profound effects on chemical distribution. Such alterations can subsequently alter the exposure to which organisms are subjected. This study examined the influence of point versus nonpoint sources in structuring the distribution of chemicals in a simulated flowing freshwater habitat. The fine-scale (molecular) spatio-temporal distribution of chemicals was measured in situ using an electrochemical detector. Molecular concentration at varying distance and height from the source was quantified using dopamine coupled with an electrochemical detection system. The fine-scale distribution of chemical plumes from point and nonpoint sources showed significant differences in how organisms will be exposed to chemicals. Overall, this study characterized plumes from nonpoint sources as having significantly longer peak lengths and rise times as well as greater peak heights and maximum slopes than plumes from point sources, thus providing a significantly different exposure paradigm. This quantification of how chemicals move differently throughout a fluid medium when introduced from point and nonpoint sources allows a greater understanding of how chemical plumes can potentially affect aquatic ecosystems. PMID:25552326

  5. ASSESSMENT OF RISK REDUCTION STRATEGIES FOR THE MANAGEMENT OF AGRICULTURAL NONPOINT SOURCE PESTICIDE RUNOFF IN ESTUARINE ECOSYSTEMS

    EPA Science Inventory

    Agricultural nonpoint source (NPS) runoff may result in significant discharges of pesticides, suspended sediments, and fertilizers into estuarine habitats adjacent to agricultural areas or downstream from agricultural watersheds. Exposure of estuarine fin fish and shellfish to to...

  6. An interdisciplinary assessment of regional-scale nonpoint source ground-water vulnerability; theory and application

    USGS Publications Warehouse

    Bernknopf, Richard L.; Dinitz, Laura B.; Loague, Keith

    2001-01-01

    An integrated earth science-economics model, developed within a geographic information system (GIS), combines a regional-scale nonpoint source vulnerability assessment with a specific remediation measure to avoid unnecessary agricultural production costs associated with the use of agrochemicals in the Pearl Harbor basin on the island of Oahu, Hawaii. This approach forms the core of a risk-based regulation for the application of agrochemicals and estimates the benefits of an information-based approach to decisionmaking.

  7. NASA-modified precipitation products to improve USEPA nonpoint source water quality modeling for the Chesapeake Bay.

    PubMed

    Nigro, Joseph; Toll, David; Partington, Ed; Ni-Meister, Wenge; Lee, Shihyan; Gutierrez-Magness, Angelica; Engman, Ted; Arsenault, Kristi

    2010-01-01

    The USEPA has estimated that over 20,000 water bodies within the United States do not meet water quality standards. One of the regulations in the Clean Water Act of 1972 requires states to monitor the total maximum daily load, or the amount of pollution that can be carried by a water body before it is determined to be "polluted," for any watershed in the United States (Copeland, 2005). In response to this mandate, the USEPA developed Better Assessment Science Integrating Nonpoint Sources (BASINS) as a decision support tool for assessing pollution and to guide the decision-making process for improving water quality. One of the models in BASINS, the Hydrological Simulation Program-Fortran (HSPF), computes continuous streamflow rates and pollutant concentration at each basin outlet. By design, precipitation and other meteorological data from weather stations serve as standard model input. In practice, these stations may be unable to capture the spatial heterogeneity of precipitation events, especially if they are few and far between. An attempt was made to resolve this issue by substituting station data with NASA-modified/NOAA precipitation data. Using these data within HSPF, streamflow was calculated for seven watersheds in the Chesapeake Bay Basin during low flow periods, convective storm periods, and annual flows. In almost every case, the modeling performance of HSPF increased when using the NASA-modified precipitation data, resulting in better streamflow statistics and, potentially, in improved water quality assessment. PMID:20830927

  8. An inexact fuzzy two-stage stochastic model for quantifying the efficiency of nonpoint source effluent trading under uncertainty.

    PubMed

    Luo, B; Maqsood, I; Huang, G H; Yin, Y Y; Han, D J

    2005-07-15

    Reduction of nonpoint source (NPS) pollution from agricultural lands is a major concern in most countries. One method to reduce NPS pollution is through land retirement programs. This method, however, may result in enormous economic costs especially when large sums of croplands need to be retired. To reduce the cost, effluent trading can be employed to couple with land retirement programs. However, the trading efforts can also become inefficient due to various uncertainties existing in stochastic, interval, and fuzzy formats in agricultural systems. Thus, it is desired to develop improved methods to effectively quantify the efficiency of potential trading efforts by considering those uncertainties. In this respect, this paper presents an inexact fuzzy two-stage stochastic programming model to tackle such problems. The proposed model can facilitate decision-making to implement trading efforts for agricultural NPS pollution reduction through land retirement programs. The applicability of the model is demonstrated through a hypothetical effluent trading program within a subcatchment of the Lake Tai Basin in China. The study results indicate that the efficiency of the trading program is significantly influenced by precipitation amount, agricultural activities, and level of discharge limits of pollutants. The results also show that the trading program will be more effective for low precipitation years and with stricter discharge limits. PMID:16084964

  9. A Probabilistic Approach for Analysis of Modeling Uncertainties in Quantification of Trading Ratios in Nonpoint to Point Source Nutrient Trading Programs

    NASA Astrophysics Data System (ADS)

    Tasdighi, A.; Arabi, M.

    2015-12-01

    Quantifying the nonpoint source pollutant loads and assessing the water quality benefits of conservation practices (BMPs) are prone to different types of uncertainties which have to be taken into account when developing nutrient trading programs. Although various types of modeling uncertainties (parameter, input and structure) have been examined in the literature more or less, the impact of modeling uncertainties on evaluation of BMPs has not been addressed sufficiently. Currently, "trading ratios" are used within nutrient trading programs to account for variability of nonpoint source loads. However, we were not able to find any case of some rigorous scientific approach to account for any type of uncertainties in trading ratios. In this study, Bayesian inferences were applied to incorporate input, parameter and structural uncertainties using a statistically valid likelihood function. IPEAT (Integrated Parameter Estimation and Uncertainty Analysis Tool), a framework developed for simultaneous evaluation of parameterization, input data, model structure, and observation data uncertainty and their contribution to predictive uncertainty was used to quantify the uncertainties in effectiveness of agricultural BMPs while propagating different sources of uncertainty. SWAT was used as the simulation model. SWAT parameterization was done for three different model structures (SCS CN I, SCS CN II and G&A methods) using a Bayesian based Markov Chain Monte Carlo (MCMC) method named Differential Evolution Adaptive Metropolis (DREAM). For each model structure, the Integrated Bayesian Uncertainty Estimator (IBUNE) was employed to generate latent variables from input data. Bayesian Model Averaging (BMA) was then used to combine the models and Expectation-Maximization (EM) optimization technique was used to estimate the BMA weights. Using this framework, the impact of different sources of uncertainty on nutrient loads from nonpoint sources and subsequently effectiveness of BMPs in

  10. An Experimental Study on Using Rare Earth Elements to Trace Non-point source Phosphorous LossA

    NASA Astrophysics Data System (ADS)

    Liang, T.

    2011-12-01

    Controlling phosphorous (P) inputs through management of its sources and transport is critical for limiting freshwater eutrophication. Rare earth elements (REEs) have been successfully used in the analysis of soil erosion and pollutant sources, as well as in the analysis of mineral genesis. To better understand the potential for REE use in tracing non-point sources of P, we examined the combined fate of REEs and P in Chinese soils amended with REEs and documented the formation of REE-P compounds. Laboratory leaching experiments and artificial simulated rainfall experiments were conducted. Vertical leaching transfers of REEs and P were relatively small, with transport depths less than 6 cm for most REEs and P. Export of applied REEs in leachate accounted for less that 5% of inputs. The vertical mobility order of REEs and P in Chinese soils was greatest for purple soil, followed by terra nera soil, then red soil, followed by cinnamon soil, and finally loess soil. Losses of rare earth elements and P in surface runoff exhibited a parabolic relationship to simulated rainfall intensity. With greater exogenous La application, the amount of water soluble P, bicarbonate-extractable P and hydroxide-extractable P decreased significantly, while acid-extractable and residual forms of P increased significantly. In addition, characteristics of exogenous rare earth elements (REEs) and P and their losses with surface runoff (both in the water and sediments) during simulated rainfall experiments (83 mm h-1) were investigated. The results revealed that most REEs (La, 94%; Nd, 93%; Sm, 96%) and P (96%) transported with sediments in the runoff. The total amounts of losses of REEs and P in the runoff were significantly correlated, suggesting the possibility of using REEs to trace the fate of agricultural nonpoint P losses.

  11. Air pollution source identification

    NASA Technical Reports Server (NTRS)

    Fordyce, J. S.

    1975-01-01

    Techniques for air pollution source identification are reviewed, and some results obtained with them are evaluated. Described techniques include remote sensing from satellites and aircraft, on-site monitoring, and the use of injected tracers and pollutants themselves as tracers. The use of a large number of trace elements in ambient airborne particulate matter as a practical means of identifying sources is discussed in detail. Sampling and analysis techniques are described, and it is shown that elemental constituents can be related to specific source types such as those found in the earth's crust and those associated with specific industries. Source identification sytems are noted which utilize charged particle X-ray fluorescence analysis of original field data.

  12. Air pollution source identification

    NASA Technical Reports Server (NTRS)

    Fordyce, J. S.

    1975-01-01

    The techniques available for source identification are reviewed: remote sensing, injected tracers, and pollutants themselves as tracers. The use of the large number of trace elements in the ambient airborne particulate matter as a practical means of identifying sources is discussed. Trace constituents are determined by sensitive, inexpensive, nondestructive, multielement analytical methods such as instrumental neutron activation and charged particle X-ray fluorescence. The application to a large data set of pairwise correlation, the more advanced pattern recognition-cluster analysis approach with and without training sets, enrichment factors, and pollutant concentration rose displays for each element is described. It is shown that elemental constituents are related to specific source types: earth crustal, automotive, metallurgical, and more specific industries. A field-ready source identification system based on time and wind direction resolved sampling is described.

  13. Groundwater as a nonpoint source of atrazine and deethylatrazine in a river during base flow conditions

    USGS Publications Warehouse

    Squillace, Paul J.; Thurman, E.M.; Furlong, Edward T.

    1993-01-01

    Alluvial groundwater adjacent to the main stem river is the principal nonpoint source of atrazine and deethylatrazine in the Cedar River of Iowa after the river has been in base flow conditions for 5 days. Between two sites along a 116-km reach of the Cedar River, tributaries contributed about 25% of the increase in the atrazine and deethylatrazine load, whereas groundwater from the alluvial aquifer contributed at least 75% of the increase in load. Within the study area, tributaries aggregate almost all of the discharge from tile drains, and yet the tributaries still only contribute 25% of the increase in loads in the main stem river. At an unfamned study site adjacent to the Cedar River, the sources of atrazine and deethylatrazine in the alluvial groundwater are bank storage of river water and groundwater recharge from areas distant from the river. Atrazine and deethylatrazine associated with bank storage water will provide larger concentrations to the river during early base flow conditions. After the depletion of bank storage, stable and smaller concentrations of atrazine and deethylatrazine, originating from groundwater recharge, continue to be discharged from the alluvial aquifer to the river; thus these results indicate that alluvial aquifers are an important nonpoint source of atrazine and deethylatrazine in rivers during base flow.

  14. The removal of nutrients from non-point source wastewater by a hybrid bioreactor.

    PubMed

    Wu, Yonghong; Hu, Zhengyi; Yang, Linzhang; Graham, Bruce; Kerr, Philip G

    2011-02-01

    The aim of this project was to establish an economical and environmentally benign biotechnology for removing nutrients from non-point source wastewater. The proposal involves a hybrid bioreactor comprised of sequential anaerobic, anoxic and aerobic (A(2)/O) processes and an eco-ditch being constructed and applied in a suburban area, Kunming, south-western China, where wastewater was discharged from an industrial park and suburban communities. The results show that the hybrid bioreactor fosters heterotrophic and autotrophic microorganisms. When the hydraulic load is 200 m(3) per day with the running mode in 12h cycles, the removal efficiencies of the nutrients were 81% for TP, 74% for TDP, 82% for TN, 79% for NO(3)-N and 86% for NH(4)-N. The improved bacterial community structure and bacterial habitats further implied enhanced water quality and indicates that the easily-deployed, affordable and environmentally-friendly hybrid bioreactor is a promising bio-measure for removing high loadings of nutrients from non-point source wastewater. PMID:21093255

  15. Making Our Nonpoint Source Pollution Education Programs Effective.

    ERIC Educational Resources Information Center

    Shepard, Robin

    1999-01-01

    The rate of adoption of nutrient management by farmers in Wisconsin watersheds was compared for a program using diffuse communication strategies and one using one-to-one information transfer. Information transfer increased adoption of specific practices and decreased application of excessive nitrogen and phosphorus. (SK)

  16. Nonpoint Source Road Salt Pollution from Urban Stormwater

    NASA Astrophysics Data System (ADS)

    DeGaetano, S.; Walter, M. T.

    2014-12-01

    In colder climates, such as the Northeast, road salts are commonly applied to deice roads in order to increase pedestrian and driver safety. This study was conducted to establish the mass if NaCl entering the local aquatic systems from Cornell's campus. Using trail cameras, two typical storm water pipes (draining into Cascadilla Creek) were monitored to determine the volume of runoff on an hourly bases. Grab samples were taken three times a week obtain storm water chloride concentration. In general, the average measured salt concentration was found to be 3.61 g/L, while high precipitation events Cl- concentration spiked to levels exceeding 12 g/L (≈ 20 g/L of salt). Combining runoff volumes and salt concentration values, a mass per drainage area was calculated for each monitored pipe. Outfall #1, located just upstream from the Wilson Synchrotron Module, expelled 262,300 kg of salt over a 42-day period of data collection while Outfall#2 discharged 4160 kg during the same period. These results were averaged and then applied to the total impervious area on Cornell's campus to approximate the total mass of sodium chloride leaving campus during the period of data collection.

  17. Influencing factor analysis of phosphorus loads from non-point source: a case study in central China.

    PubMed

    Zhuang, Yanhua; Hong, Song; Zhan, F Benjamin; Zhang, Liang

    2015-11-01

    The influence factor analysis for non-point source (NPS) pollution is very important to taking effective water pollution control measures. In this study, the self-organizing map (SOM) and linear model analysis were used to analyze the relationships between total phosphorus (TP) loads and influencing factors, both qualitatively and quantitatively. The land-use type, topography, and vegetation coverage were the main factors influencing the export of TP loads in Tangxun watershed. Slope and normalized difference vegetation index (NDVI) were chosen as characteristic indices of topography and vegetation coverage, respectively. For the whole watershed, the high TP loads were mainly distributed in areas with high slope and low vegetation coverage for a specific land-use type. For different land types, the slope significantly influenced the export of TP loads in waste/bare land and forest/green land while NDVI influenced the export of TP loads in forest/green land and farmland. In terms of multi-factor analysis, the comprehensive influence of slope and NDVI on TP loads showed as waste/bare land>forest/green land>farmland>rural/urban construction land. PMID:26514801

  18. Analysis of bottom sediment to estimate nonpoint-source phosphorus loads for 1981-96 in Hillsdale Lake, northeast Kansas

    USGS Publications Warehouse

    Juracek, K.E.

    1997-01-01

    Bottom sediment in Hillsdale Lake, northeast Kansas, was analyzed as a means of estimating the annual load of total phosphorus deposited in the lake from nonpoint sources. Topographic, bathymetric, and sediment-core data were used to estimate the total mass of phosphorus in the lake-bottom sediment. Available streamflow and water-quality data were used to compute the mean annual mass of phosphorus (dissolved plus suspended) exiting the lake as well as the mean annual load of phosphorus added to the lake from point sources. A simple mass balance then was used to compute the mean annual load of phosphorus from nonpoint sources. Mean annual sediment deposition from 1981 through 1996 was estimated to be 265 million pounds (120 million kilograms). The total mass of phosphorus in the lake-bottom sediment was estimated to be 924,000 kilograms, with a mean annual load of 62,000 kilograms. The mean annual mass of phosphorus exiting in the lake out-flow was estimated to be about 8,000 kilograms. The mean annual loads of phosphorus added to the lake from point and nonpoint sources were estimated to be 5,000 and 65,000 kilograms, respectively. Thus, the contribution to the total mean annual phosphorus load in Hillsdale Lake from point sources is about 7 percent and from nonpoint sources, about 93 percent.

  19. Using NASA and Earth Science Products to Improve EPA Non-point Source Water Quality Modeling for the Chesapeake Bay

    NASA Astrophysics Data System (ADS)

    Toll, D.; Engman, T.; Edward, P.; Magness, A.; Townsend, P.; N-Meister, W.; Nigro, J.; Lee, S.

    2007-12-01

    The Environmental Protection Agency (EPA) estimates that over 20,000 bodies of water throughout the country do not meet water quality standards. Nonpoint sources -- pollution from urban, agricultural, and forest land that is transported by runoff -- typically cause 90 percent of impairments. EPA has developed the BASINS (Better Assessment Science Integrating Point and Nonpoint Sources) modeling system for performing numerous water quality studies. The key to this suite of models is the Hydrological Simulation Program - Fortran (HSPF), which calculates daily stream flow rates and the corresponding pollutant concentrations at the watershed outlet. EPA has partnered with NASA to use high spatial and temporal hydrological variables (e.g., precipitation, evaporation, etc.) from the NASA Land Information System (LIS) and land cover/vegetative indices derived from primarily MODIS and Landsat satellite data non-point source water quality for the Chesapeake Bay Basin. For the precipitation and evaporation data, EPA-based BASINS-HSPF streamflow runs were conducted on seven study watersheds in the Chesapeake Bay Basin. Sets of runs using precipitation from default weather stations, the NASA LIS 1/8th degree precipitation, NOAA Stage IV precipitation, NASA LIS Noah land surface model evapotranspiration datasets were conducted for each watershed. The output statistics summarized reveal that for 74% of the runs, the NASA LIS 1/8th degree and Stage IV precipitation-based runs performed better than when using only the default EPA precipitation station data. In addition, an automatic calibration method ('PEST') and Noah land surface model evapotranspiration (ET) being further incorporated. The empirical ability of generalized spectral indices and land cover derived from Landsat and MODIS was tested for predicting stream water nitrogen export from predominately forested watersheds undergoing disturbance. The disturbance index, a summary index that is easily computed from Landsat

  20. RIVER BASIN VALIDATION OF THE WATER QUALITY ASSESSMENT METHODOLOGY FOR SCREENING NONDESIGNATED 208 AREAS. VOLUME I: NONPOINT SOURCE LOAD ESTIMATION

    EPA Science Inventory

    In earlier work under the sponsorship of EPA, loading functions were developed by Midwest Research Institute (MRI) for estimating the quantities of different diffuse loads entering receiving waters from nonpoint sources and a screening methodology was produced by Tetra Tech, Inc....

  1. ASSESSING NON-POINT SOURCES OF NITROGEN TO SMALL STREAMS IN THE SOUTH FORK BROAD RIVER WATERSHED (GEORGIA, USA)

    EPA Science Inventory

    The National Land Cover Data (NLCD) is a land cover classification derived from Landsat Thematic Mapper satellite data collected in the early to mid-1990s. In this work, land use coverages calculated from the NLCD database are used to assess the impact of non-point sources on the...

  2. MODELING THE DISTRIBUTION OF NONPOINT NITROGEN SOURCES AND SINKS IN THE NEUSE RIVER BASIN OF NORTH CAROLINA, USA

    EPA Science Inventory

    This study quantified nonpoint nitrogen (N) sources and sinks across the 14,582 km2 Neuse River Basin (NRB) located in North Carolina, to provide a tabular database to initialize in-stream N decay models and graphic overlay products for the development of management approaches to...

  3. Metabolomics for in situ environmental monitoring of surface waters impacted by contaminants from both point and non-point sources

    EPA Science Inventory

    We investigated the efficacy of metabolomics for field-monitoring of fish exposed to waste water treatment plant (WWTP) effluents and non-point sources of chemical contamination. Lab-reared male fathead minnows (Pimephales promelas, FHM) were held in mobile monitoring units and e...

  4. Point- and nonpoint-source trace elements in a wild and scenic river of northern New Mexico.

    USGS Publications Warehouse

    Garn, H.S.

    1985-01-01

    Variations in water quality of the upper Rio Grande and Red River are presented. A downstream increase in concentrations of various constituents, at times approaching or exceeding water quality standards, occurred due to leaching of natural ore bodies and permitted discharges from molybdenum mill tailings ponds. Nonpoint sources are a major cause of elevated trace element concentrations.-from Author

  5. GIS-based source identification and apportionment of diffuse water pollution: perfluorinated compound pollution in the Tokyo Bay basin.

    PubMed

    Zushi, Yasuyuki; Masunaga, Shigeki

    2011-11-01

    To efficiently reduce perfluorinated compound (PFC) pollution, it is important to have an understanding of PFC sources and their contribution to the pollution. In this study, source identification of diffuse water pollution by PFCs was conducted using a GIS-based approach. Major components of the source identification were collection of the monitoring data and preparation of the corresponding geographic information that was extracted from a constructed GIS database. The spatially distributed pollution factors were then explored by multiple linear regression analysis, after which they were visually expressed using GIS. Among the 35 PFC homologues measured in a survey of the Tokyo Bay basin, 18 homologues were analyzed. Pollution by perfluorooctane sulfonate (PFOS) was explained well by the percentage of arterial traffic area in the basin, and the 84% variance of the measured PFOS concentration was explained by two geographic variables, arterial traffic area and population. Source apportionment between point and nonpoint sources was conducted based on the results of the analysis. The contribution of PFOS from nonpoint sources was comparable to that from point sources in several major rivers flowing into Tokyo Bay. Source identification and apportionment using the GIS-based approach was shown to be effective, especially for ubiquitous types of pollution, such as PFC pollution. PMID:21885084

  6. Non-point pollution of groundwater from agricultural activities in Mediterranean Spain: the Balearic Islands case study

    NASA Astrophysics Data System (ADS)

    Candela, L.; Wallis, K. J.; Mateos, R. M.

    2008-04-01

    Mediterranean Spain is a region with intensive agricultural production combined with an important seasonal water demand for water supply. High application rates of inorganic nitrogen fertiliser, input of plant protection products and intensive irrigation, sometimes with treated wastewater, is a common practice. As a result, most aquifers show nitrate contamination problems of agricultural origin. Data on pesticide residues is scarce, as systematic monitoring is not currently done. In Majorca Island, values up to 700 mg/l of nitrate in groundwater have been observed. To analyse the current situation derived from non-point pollution, several actions have been taken at different scales: declaration of a nitrate vulnerable zone, field experiments to evaluate nitrogen transport to the aquifer and the development of a GIS-simulation model to generate nitrate risk maps.

  7. Nonpoint-pollution discharge permit testing and control strategies at Naval Air Station Whidbey Island. Master's thesis

    SciTech Connect

    Vogelsang, K.G.

    1991-01-01

    The purpose of this study was to analyze systematically a nonpoint storm water monitoring program at Naval Air Station Whidbey Island, Washington, to determine if more relevant data can be obtained at lower cost by revising the sampling location, frequency, or pollutants of interest. Current remedial investigations of contaminants in sediments, station hazardous material use information and station management plans provided the bulk of the data. Review of watersheds indicated that potential contamination by 26 compounds may be present in the storm runoff. Testing to identify the presence of these compounds is required to renew an existing National Pollution Discharge Elimination System permit for the air station. It was also found that the frequency of sampling could be reduced from 52 events per year to about 30 with no significant loss of statistical accuracy, thereby reducing the recurring cost of the sampling program. Also discussed are management practices and structural improvements that are technically feasible for controlling the two most significant pollutants, oil and grease and suspended solids. Best Management Practices are recommended to prevent or clean the spill of aviation fuel at the spill location. Use of synthetic oil-sorbent booms is recommended in lieu of the existing baffle treatment system.

  8. Spatial and temporal variations in non-point source losses of nitrogen and phosphorus in a small agricultural catchment in the Three Gorges Region.

    PubMed

    Chen, Chenglong; Gao, Ming; Xie, Deti; Ni, Jiupai

    2016-04-01

    Losses of agricultural pollutants from small catchments are a major issue for water quality in the Three Gorges Region. Solutions are urgently needed. However, before pollutant losses can be controlled, information about spatial and temporal variations in pollutant losses is needed. The study was carried out in the Wangjiagou catchment, a small agricultural catchment in Fuling District, Chongqing, and the data about non-point source losses of nitrogen and phosphorus was collected here. Water samples were collected daily by an automatic water sampler at the outlets of two subcatchments from 2012 to 2014. Also, samples of surface runoff from 28 sampling sites distributed through the subcatchments were collected during 12 rainfall events in 2014. A range of water quality variables were analyzed for all samples and were used to demonstrate the variation in non-point losses of nitrogen and phosphorus over a range of temporal and spatial scales and in different types of rainfall in the catchment. Results showed that there was a significant linear correlation between the mass concentrations of total nitrogen (TN) and nitrate (NO3-N) in surface runoff and that the relationship was maintained with changes in time. Concentrations of TN and NO3-N peaked after fertilizer was applied to crops in spring and autumn; concentrations decreased rapidly after the peak values in spring but declined slowly in autumn. N and P concentrations fluctuated more and showed a greater degree of dispersion during the spring crop cultivation period than those in autumn. Concentrations of TN and NO3-N in surface runoff were significantly and positively correlated with the proportion of the area that was planted with corn and mustard tubers, but were negatively correlated with the proportion of the area taken up with rice and mulberry plantations. The average concentrations of TN and NO3-N in surface runoff reached the highest level from the sampling points at the bottom of the land used for corn

  9. Spatial and temporal variations in non-point source losses of nitrogen and phosphorus in a small agricultural catchment in the Three Gorges Region.

    PubMed

    Chen, Chenglong; Gao, Ming; Xie, Deti; Ni, Jiupai

    2016-04-01

    Losses of agricultural pollutants from small catchments are a major issue for water quality in the Three Gorges Region. Solutions are urgently needed. However, before pollutant losses can be controlled, information about spatial and temporal variations in pollutant losses is needed. The study was carried out in the Wangjiagou catchment, a small agricultural catchment in Fuling District, Chongqing, and the data about non-point source losses of nitrogen and phosphorus was collected here. Water samples were collected daily by an automatic water sampler at the outlets of two subcatchments from 2012 to 2014. Also, samples of surface runoff from 28 sampling sites distributed through the subcatchments were collected during 12 rainfall events in 2014. A range of water quality variables were analyzed for all samples and were used to demonstrate the variation in non-point losses of nitrogen and phosphorus over a range of temporal and spatial scales and in different types of rainfall in the catchment. Results showed that there was a significant linear correlation between the mass concentrations of total nitrogen (TN) and nitrate (NO3-N) in surface runoff and that the relationship was maintained with changes in time. Concentrations of TN and NO3-N peaked after fertilizer was applied to crops in spring and autumn; concentrations decreased rapidly after the peak values in spring but declined slowly in autumn. N and P concentrations fluctuated more and showed a greater degree of dispersion during the spring crop cultivation period than those in autumn. Concentrations of TN and NO3-N in surface runoff were significantly and positively correlated with the proportion of the area that was planted with corn and mustard tubers, but were negatively correlated with the proportion of the area taken up with rice and mulberry plantations. The average concentrations of TN and NO3-N in surface runoff reached the highest level from the sampling points at the bottom of the land used for corn

  10. Arsenic pollution sources.

    PubMed

    Garelick, Hemda; Jones, Huw; Dybowska, Agnieszka; Valsami-Jones, Eugenia

    2008-01-01

    Arsenic is a widely dispersed element in the Earth's crust and exists at an average concentration of approximately 5 mg/kg. There are many possible routes of human exposure to arsenic from both natural and anthropogenic sources. Arsenic occurs as a constituent in more than 200 minerals, although it primarily exists as arsenopyrite and as a constituent in several other sulfide minerals. The introduction of arsenic into drinking water can occur as a result of its natural geological presence in local bedrock. Arsenic-containing bedrock formations of this sort are known in Bangladesh, West Bengal (India), and regions of China, and many cases of endemic contamination by arsenic with serious consequences to human health are known from these areas. Significant natural contamination of surface waters and soil can arise when arsenic-rich geothermal fluids come into contact with surface waters. When humans are implicated in causing or exacerbating arsenic pollution, the cause can almost always be traced to mining or mining-related activities. Arsenic exists in many oxidation states, with arsenic (III) and (V) being the most common forms. Similar to many metalloids, the prevalence of particular species of arsenic depends greatly on the pH and redox conditions of the matrix in which it exists. Speciation is also important in determining the toxicity of arsenic. Arsenic minerals exist in the environment principally as sulfides, oxides, and phosphates. In igneous rocks, only those of volcanic origin are implicated in high aqueous arsenic concentrations. Sedimentary rocks tend not to bear high arsenic loads, and common matrices such as sands and sandstones contain lower concentrations owing to the dominance of quartz and feldspars. Groundwater contamination by arsenic arises from sources of arsenopyrite, base metal sulfides, realgar and orpiment, arsenic-rich pyrite, and iron oxyhydroxide. Mechanisms by which arsenic is released from minerals are varied and are accounted for by

  11. Enhancements of nonpoint source monitoring of volatile organic compounds in ground water

    USGS Publications Warehouse

    Lapham, W.W.; Moran, M.J.; Zogorski, J.S.

    2000-01-01

    The U.S. Geological Survey (USGS) has compiled a national retrospective data set of analyses of volatile organic compounds (VOCs) in ground water of the United States. The data are from Federal, State, and local nonpoint-source monitoring programs, collected between 1985–95. This data set is being used to augment data collected by the USGS National Water-Quality Assessment (NAWQA) Program to ascertain the occurrence of VOCs in ground water nationwide. Eleven attributes of the retrospective data set were evaluated to determine the suitability of the data to augment NAWQA data in answering occurrence questions of varying complexity. These 11 attributes are the VOC analyte list and the associated reporting levels for each VOC, well type, well-casing material, type of openings in the interval (screened interval or open hole), well depth, depth to the top and bottom of the open interval(s), depth to water level in the well, aquifer type (confined or unconfined), and aquifer lithology. VOCs frequently analyzed included solvents, industrial reagents, and refrigerants, but other VOCs of current interest were not frequently analyzed. About 70 percent of the sampled wells have the type of well documented in the data set, and about 74 percent have well depth documented. However, the data set generally lacks documentation of other characteristics, such as well-casing material, information about the screened or open interval(s), depth to water level in the well, and aquifer type and lithology. For example, only about 20 percent of the wells include information on depth to water level in the well and only about 14 percent of the wells include information about aquifer type. The three most important enhancements to VOC data collected in nonpoint-source monitoring programs for use in a national assessment of VOC occurrence in ground water would be an expanded VOC analyte list, recording the reporting level for each analyte for every analysis, and recording key ancillary

  12. Nonpoint source solute transport normal to aquifer bedding in heterogeneous, Markov chain random fields

    NASA Astrophysics Data System (ADS)

    Zhang, Hua; Harter, Thomas; Sivakumar, Bellie

    2006-06-01

    Facies-based geostatistical models have become important tools for analyzing flow and mass transport processes in heterogeneous aquifers. Yet little is known about the relationship between these latter processes and the parameters of facies-based geostatistical models. In this study, we examine the transport of a nonpoint source solute normal (perpendicular) to the major bedding plane of an alluvial aquifer medium that contains multiple geologic facies, including interconnected, high-conductivity (coarse textured) facies. We also evaluate the dependence of the transport behavior on the parameters of the constitutive facies model. A facies-based Markov chain geostatistical model is used to quantify the spatial variability of the aquifer system's hydrostratigraphy. It is integrated with a groundwater flow model and a random walk particle transport model to estimate the solute traveltime probability density function (pdf) for solute flux from the water table to the bottom boundary (the production horizon) of the aquifer. The cases examined include two-, three-, and four-facies models, with mean length anisotropy ratios for horizontal to vertical facies, ek, from 25:1 to 300:1 and with a wide range of facies volume proportions (e.g., from 5 to 95% coarse-textured facies). Predictions of traveltime pdfs are found to be significantly affected by the number of hydrostratigraphic facies identified in the aquifer. Those predictions of traveltime pdfs also are affected by the proportions of coarse-textured sediments, the mean length of the facies (particularly the ratio of length to thickness of coarse materials), and, to a lesser degree, the juxtapositional preference among the hydrostratigraphic facies. In transport normal to the sedimentary bedding plane, traveltime is not lognormally distributed as is often assumed. Also, macrodispersive behavior (variance of the traveltime) is found not to be a unique function of the conductivity variance. For the parameter range

  13. HYDROCARBON POLLUTANTS FROM STATIONARY SOURCES

    EPA Science Inventory

    The report gives results of a study of hydrocarbon pollutants from stationary sources. Early in the study, readily available information was assembled on stationary sources of hydrocarbon emissions and effluents. Information was also obtained on process descriptions, operating pa...

  14. Differentiating nonpoint sources of deisopropylatrazine in surface water using discrimination diagrams.

    PubMed

    Meyer, M T; Thurman, E M; Goolsby, D A

    2001-01-01

    Pesticide degradates account for a significant portion of the pesticide load in surface water. Because pesticides with similar structures may degrade to the same degradate, it is important to distinguish between different sources of parent compounds that have different regulatory and environmental implications. A discrimination diagram, which is a sample plot of chemical data that differentiates between different parent compounds, was used for the first time to distinguish whether sources other than atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) contributed the chlorinated degradate, deisopropylatrazine (DIA; 6-chloro-N-ethyl-1,3,5-triazine-2,4-diamine) to the Iroquois and Delaware Rivers. The concentration ratio of deisopropylatrazine to deethylatrazine [6-chloro-N-(1-methylethyl)1,3,5-triazine-2,4-diamine], called the D2R, was used to discriminate atrazine as a source of DIA from other parent sources, such as cyanazine (2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropionitrile) and simazine (6-chloro-N,N'-diethyl-1,3,5-triazine-2,4diamine). The ratio of atrazine to cyanazine (ACR) used in conjunction with the D2R showed that after atrazine, cyanazine was the main contributor of DIA in surface water. The D2R also showed that cyanazine, and to a much lesser extent simazine, contributed a considerable amount (approximately 40%) of the DIA that was transported during the flood of the Mississippi River in 1993. The D2R may continue to be a useful discriminator in determining changes in the nonpoint sources of DIA in surface water as cyanazine is currently being removed from the market. PMID:11577893

  15. Differentiating nonpoint sources of deisopropylatrazine in surface water using discrimination diagrams

    USGS Publications Warehouse

    Meyer, M.T.; Thurman, E.M.; Goolsby, D.A.

    2001-01-01

    Pesticide degradates account for a significant portion of the pesticide load in surface water. Because pesticides with similar structures may degrade to the same degradate, it is important to distinguish between different sources of parent compounds that have different regulatory and environmental implications. A discrimination diagram, which is a sample plot of chemical data that differentiates between different parent compounds, was used for the first time to distinguish whether sources other than atrazine (6-chloro-N2-ethyl-N4-isopropyl-1, 3,5-triazine-2,4-diamine) contributed the chlorinated degradate, deisopropylatrazine (DIA; 6-chloro-N-ethyl-1,3,5-triazine-2,4-diamine) to the Iroquois and Delaware Rivers. The concentration ratio of deisopropylatrazine to deethylatrazine [6-chloro-N-(1-methylethyl)-1, 3,5-triazine-2,4-diamine], called the D2R, was used to discriminate atrazine as a source of DIA from other parent sources, such as cyanazine (2-[[4-chloro-6-(ethylamino)-1,3,5-triazin-2-yl]amino]-2-methylpropionitrile) and simazine (6-chloro-N,N???-diethyl-1,3,5-triazine-2,4-diamine). The ratio of atrazine to cyanazine (ACR) used in conjunction with the D2R showed that after atrazine, cyanazine was the main contributor of DIA in surface water. The D2R also showed that cyanazine, and to a much lesser extent simazine, contributed a considerable amount (???40%) of the DIA that was transported during the flood of the Mississippi River in 1993. The D2R may continue to be a useful discriminator in determining changes in the nonpoint sources of DIA in surface water as cyanazine is currently being removed from the market.

  16. Validation and future predictions based on a new Non-Point Source Assessment Toolbox, applied to the Central Valley, California

    NASA Astrophysics Data System (ADS)

    Kourakos, G.; Harter, T.

    2011-12-01

    Groundwater is a major irrigation water source in semi-arid regions. It is also vulnerable to Non-Point Source (NPS) contamination, particularly from nitrate (NO3-) as a result of agricultural practices. To support sound policy decisions we developed a physically based flow and transport model framework to understand and predict the fate of contaminants within regional aquifer systems. In large aquifers, the total source area of pollutants typically cover several thousand square kilometers, whilst individual sources typically do not exceed a few hundred square meters. The large contrast in these scenarios result in NPS modeling tasks that are computationally demanding, and the classical 3D models that solve the Advection-Dispersion Equation (ADE) are often not applicable due to computer memory limitations, numerical dispersion and numerical instabilities. Here, we developed and employed a number of numerical techniques to assemble a Non-Point Source Assessment Toolbox (NPSAT). The NPSAT is a quasi-3D model, combining a flow model and a streamline transport model. The flow model solves the groundwater flow equation using very fine discretization. For very large groundwater basins, a simplistic decomposition method is applied, splitting the aquifer into several overlapping sub-domains and solving to produce a high resolution velocity field. This velocity field is subsequently utilized within the transport model, where backward particle tracking links contamination sources with discharge surfaces using a large number of streamlines. For each streamline the 1D ADE is solved, assuming a unit pulse loading at the source side and a free exit boundary condition at the discharge surface side. From this, a Unit Response Function (URF) is obtained at the discharge surface side. Subsequently, actual Breakthrough Curves (BTCs) can be quickly computed from actual or hypothetical loading histories, by convoluting the URFs with real loading functions. The URFs are stored into a

  17. Percentage of Probability of Nonpoint-Source Nitrate Contamination of Recently Recharged Ground Water in the High Plains Aquifer

    USGS Publications Warehouse

    Qi, Sharon L.; Gurdak, Jason J.

    2006-01-01

    This raster data set represents the percentage of probability of nonpoint-source nitrate contamination (greater than the proposed background concentration of 4 milligrams per liter (mg/L) as N) of recently (defined as less than 50 years) recharged ground water in the High Plains aquifer of the United States. The High Plains aquifer covers approximately 175,000 square miles in eight States; Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming. Elevated nitrate concentrations above the background concentration have been detected in recently recharged (less than 50 years) ground water in the High Plains aquifer. This data set is derived from empirical models developed using multivariate logistic regression to evaluate the vulnerability of the High Plains aquifer to nitrate contamination from nonpoint sources. This data set was generated in a geographic information system from these models and represents the spatial extent of vulnerability of nitrate contamination greater than 4 mg/L across the aquifer.

  18. Using site-specific soil samples as a substitution for improved hydrological and nonpoint source predictions.

    PubMed

    Chen, Lei; Wang, Guobo; Zhong, Yucen; Zhao, Xin; Shen, Zhenyao

    2016-08-01

    Soil databases are one of the most important inputs for watershed models, and the quality of soil properties affects how well a model performs. The objectives of this study were to (1) quantify the sensitivity of model outputs to soil properties and to (2) use site-specific soil properties as a substitution for more accurate hydrological and nonpoint source (H/NPS) predictions. Soil samples were collected from a typical mountainous watershed in China, and the impacts of soil sample parameters on H/NPS predictions were quantified using the Soil and Water Assessment Tool (SWAT). The most sensitive parameters related to predicting flow, sediment, and total phosphorus (TP) mainly were the soil hydrological, the channel erosion processes, and the initial soil chemical environment, respectively. When the site-specific soil properties were used, the uncertainties (coefficient of variation) related to predicting the hydrology, sediment and TP decreased by 75∼80 %, 75∼84 %, and 46∼61 %, respectively. Based on changes in the Nash-Sutcliff coefficient, the model performance improved by 4.9 and 19.45 % for the hydrological and sediment model, accordingly. However, site-specific soil properties did not contribute to better TP predictions because of the high spatial variability of the soil P concentrations across the large watershed. Thus, although site-specific soil samples can be used to obtain more accurate H/NPS predictions, more sampling sites are required to apply this method in large watersheds. PMID:27146539

  19. Herbicide transport in rivers: Importance of hydrology and geochemistry in nonpoint-source contamination

    USGS Publications Warehouse

    Squillace, P.J.; Thurman, E.M.

    1992-01-01

    Alachlor, atrazine, cyanazine, metolachlor, and metribuzin were measured at six sites during 1984 and 1985 in large subbasins within the Cedar River, IA. A computer model separated the Cedar River discharge hydrograph into groundwater and overland-flow components. The concentration of herbicides in the river when groundwater was the major flow component was less than 1.0 μg/L and averaged 0.2 μg/L. The maximum concentrations of herbicides occurred when overland flow was the major component of river discharge, exceeding 50 pg/L for total herbicides. About 6% of the annual river load of atrazine was transported with the groundwater component, while 94% was transported with overland flow. From 1.5 to 5% of the atrazine applied during the year was transported from the basin. Atrazine concentrations in the river in- creased according to the discharge divided by the drainage area. This correlation indicates that rivers with large normalized 2-year peak flows have the potential to transport large concentrations of herbicides. A diagrammatic model of nonpoint-source transport of herbicides was developed that suggests that sorbed transport from fields occurs during episodes of overland flow with rapid dissolution of herbicides downstream. 

  20. Reduction of nonpoint source contamination of surface water and groundwater by starch encapsulation of herbicides

    USGS Publications Warehouse

    Mills, M.S.; Thurman, E.M.

    1994-01-01

    The loss of the preemergent herbicide atrazine in surface runoff from experimental field plots growing corn (Zea mays L.) was significantly reduced using a starchencapsulated formulation versus a conventional powdered formulation. Field edge losses of starch-encapsulated atrazine were described as following a Rayleigh distribution totaling 1.8% of applied herbicide compared to exponential powdered atrazine losses of 2.9% applied - a 40% decrease. This has important implications for the reduction of nonpoint source contamination of surface water by agricultural chemicals. Unsaturated zone release of starchencapsulated atrazine was gradual, but comparable weed control was maintained. Deethylatrazine was a major dealkylated metabolite from each formulation, and deisopropylatrazine was a minor metabolite. The determination of soil partition coefficients for deethylatrazine and deisopropylatrazine (0.4 and 0.3, respectively), aqueous solubilities (3200 and 670 mg/L, respectively), and melting points (133 and 177 ??C, respectively) confirmed that the dealkylated metabolites should move more rapidly through the soil profile to groundwater than atrazine.

  1. Landscape Based Modeling of Nonpoint Source Nitrogen Loading in the Neuse River Basin, North Carolina

    SciTech Connect

    Garten, C.T.

    2001-01-11

    The objective of this research was to arrive at a quantitative and qualitative assessment of nonpoint sources of potential excess N under different land use/land cover (LULC) categories in the Neuse River Basin on a seasonal time scale. This assessment is being supplied to EPA's Landscape Characterization Branch, National Exposure Research Laboratory, in Research Triangle Park, NC, for inclusion in a hydrologic model to predict seasonal fluxes of N from the terrestrial landscape to surface receiving waters and groundwater in the Neuse River Basin. The analysis was performed in the following five steps: (1) development of a conceptual model to predict potential excess N on land, (2) a literature review to parameterize N fluxes under LULC categories found in the Neuse River Basin, (3) acquisition of high resolution (15-m pixel) LULC data from EPA's Landscape Characterization Branch, National Exposure Research Laboratory, in Research Triangle Park, NC, (4) acquisition of a soil N inventory map for the Neuse River Basin, (5) calculations of potential excess N on a seasonal basis for the entire Neuse River Basin.

  2. Suspended particulates and bioaerosols emitted from an agricultural non-point source.

    PubMed

    Hameed, A A; Khodr, M I

    2001-02-01

    Suspended particulate and bioaerosol levels were measured at three sites downwind of an agricultural non-point source during the wheat harvesting season. Suspended particulates were detected at mean values ranging from 10000 to 2420 micrograms m-3 at distances of from 20 to 60 m downwind of the source, respectively. Airborne viable bacterial counts were recorded at mean values ranging between 10(4) and 10(6) colony forming units (cfu) m-3, whereas, Gram negative (Gram -ve) bacteria varied between 10(3) and 10(5) cfu m-3. Fungi levels were detected at mean values varying between 10(5) and 10(6) cfu m-3. However, streptomycetes were found at lower counts than those recorded for viable bacteria and fungi. Total viable bacteria, Gram -ve bacteria, fungi and streptomycetes associated hay fragments were determined at mean values of 1.5 x 10(6), 1.6 x 10(3), 2.2 x 10(4) and 6 x 10(3) cfu g-1 of hay, respectively. Cladosporium, white and red yeasts as well as Alternaria were the predominant airborne fungi, whereas, Alternaria was the dominant species associated with hay fragments. Pseudomonas, Acinetobacter and Enterobacteriaceae were the dominant Gram -ve bacteria. The most common fungal genera, such as Cladosporium and Fusarium (minor short axis), as well as Streptomyces species have an aerodynamic diameter (dae) of less than 5 microns, which can penetrate and deposit in the alveoli. Farmers and nearby residents are exposed to high levels of organic dust and bioaerosols during the wheat harvesting season. This may cause health problems in exposed persons based on toxic or allergic reactions. PMID:11354730

  3. Evaluating changes in water quality with respect to nonpoint source nutrient management strategies in the Chesapeake Bay Watershed

    NASA Astrophysics Data System (ADS)

    Keisman, J.; Sekellick, A.; Blomquist, J.; Devereux, O. H.; Hively, W. D.; Johnston, M.; Moyer, D.; Sweeney, J.

    2014-12-01

    Chesapeake Bay is a eutrophic ecosystem with periodic hypoxia and anoxia, algal blooms, diminished submerged aquatic vegetation, and degraded stocks of marine life. Knowledge of the effectiveness of actions taken across the watershed to reduce nitrogen (N) and phosphorus (P) loads to the bay (i.e. "best management practices" or BMPs) is essential to its restoration. While nutrient inputs from point sources (e.g. wastewater treatment plants and other industrial and municipal operations) are tracked, inputs from nonpoint sources, including atmospheric deposition, farms, lawns, septic systems, and stormwater, are difficult to measure. Estimating reductions in nonpoint source inputs attributable to BMPs requires compilation and comparison of data on water quality, climate, land use, point source discharges, and BMP implementation. To explore the relation of changes in nonpoint source inputs and BMP implementation to changes in water quality, a subset of small watersheds (those containing at least 10 years of water quality monitoring data) within the Chesapeake Watershed were selected for study. For these watersheds, data were compiled on geomorphology, demographics, land use, point source discharges, atmospheric deposition, and agricultural practices such as livestock populations, crop acres, and manure and fertilizer application. In addition, data on BMP implementation for 1985-2012 were provided by the Environmental Protection Agency Chesapeake Bay Program Office (CBPO) and the U.S. Department of Agriculture. A spatially referenced nonlinear regression model (SPARROW) provided estimates attributing N and P loads associated with receiving waters to different nutrient sources. A recently developed multiple regression technique ("Weighted Regressions on Time, Discharge and Season" or WRTDS) provided an enhanced understanding of long-term trends in N and P loads and concentrations. A suite of deterministic models developed by the CBPO was used to estimate expected

  4. Preliminary study on using rare earth elements to trace non-point source phosphorous loss

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The environmental fate of phosphorus (P) is of concern as P is a primary cause of freshwater eutrophication. Rare earth elements (REEs) have been successfully used in the analysis of soil erosion and pollutant sources, as well as in the analysis of mineral genesis. To better understand the potential...

  5. Estimating the susceptibility of surface water in Texas to nonpoint-source contamination by use of logistic regression modeling

    USGS Publications Warehouse

    Battaglin, William A.; Ulery, Randy L.; Winterstein, Thomas; Welborn, Toby

    2003-01-01

    In the State of Texas, surface water (streams, canals, and reservoirs) and ground water are used as sources of public water supply. Surface-water sources of public water supply are susceptible to contamination from point and nonpoint sources. To help protect sources of drinking water and to aid water managers in designing protective yet cost-effective and risk-mitigated monitoring strategies, the Texas Commission on Environmental Quality and the U.S. Geological Survey developed procedures to assess the susceptibility of public water-supply source waters in Texas to the occurrence of 227 contaminants. One component of the assessments is the determination of susceptibility of surface-water sources to nonpoint-source contamination. To accomplish this, water-quality data at 323 monitoring sites were matched with geographic information system-derived watershed- characteristic data for the watersheds upstream from the sites. Logistic regression models then were developed to estimate the probability that a particular contaminant will exceed a threshold concentration specified by the Texas Commission on Environmental Quality. Logistic regression models were developed for 63 of the 227 contaminants. Of the remaining contaminants, 106 were not modeled because monitoring data were available at less than 10 percent of the monitoring sites; 29 were not modeled because there were less than 15 percent detections of the contaminant in the monitoring data; 27 were not modeled because of the lack of any monitoring data; and 2 were not modeled because threshold values were not specified.

  6. The Other Water Pollution

    ERIC Educational Resources Information Center

    Barton, Kathy

    1978-01-01

    Nonpoint source pollution, water pollution not released at one specific identifiable point, now accounts for 50 percent of the nation's water pollution problem. Runoff is the primary culprit and includes the following sources: agriculture, mining, hydrologic modifications, and urban runoff. Economics, legislation, practices, and management of this…

  7. Sensitivity analysis of non-point sources in a water quality model applied to a dammed low-flow-reach river.

    PubMed

    Silva, Nayana G M; von Sperling, Marcos

    2008-01-01

    Downstream of Capim Branco I hydroelectric dam (Minas Gerais state, Brazil), there is the need of keeping a minimum flow of 7 m3/s. This low flow reach (LFR) has a length of 9 km. In order to raise the water level in the low flow reach, the construction of intermediate dikes along the river bed was decided. The LFR has a tributary that receives the discharge of treated wastewater. As part of this study, water quality of the low-flow reach was modelled, in order to gain insight into its possible behaviour under different scenarios (without and with intermediate dikes). QUAL2E equations were implemented in FORTRAN code. The model takes into account point-source pollution and diffuse pollution. Uncertainty analysis was performed, presenting probabilistic results and allowing identification of the more important coefficients in the LFR water-quality model. The simulated results indicate, in general, very good conditions for most of the water quality parameters The variables of more influence found in the sensitivity analysis were the conversion coefficients (without and with dikes), the initial conditions in the reach (without dikes), the non-point incremental contributions (without dikes) and the hydraulic characteristics of the reach (with dikes). PMID:18469404

  8. 78 FR 77104 - Coastal Nonpoint Pollution Control Program: Intent To Find That Oregon Has Failed To Submit an...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-20

    ... public comment on their proposal to approve, with conditions, the Oregon program (62 FR 6216). The... specified in the letter (63 FR 11655). Over time, Oregon made incremental changes to its program in order to... National Oceanic and Atmospheric Administration ENVIRONMENTAL PROTECTION AGENCY Coastal Nonpoint...

  9. Application of the Soil and Water Assessment Tool and Annualized Agricultural Non-Point Source Models in the St. Joseph River Watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated the performance of two water quality models in accordance to specific tasks designated in the USDA Agricultural Research Service Conservation Effects Assessment Project. The Soil and Water Assessment Tool (SWAT) and the Annualized Agricultural Non-Point Source (AnnAGNPS) models ...

  10. Mortality rates of pathogen indicator microorganisms discharged from point and non-point sources in an urban area.

    PubMed

    Kim, Geonha; Hur, Jin

    2010-01-01

    This research measured the mortality rates of pathogen indicator microorganisms discharged from various point and non-point sources in an urban area. Water samples were collected from a domestic sewer, a combined sewer overflow, the effluent of a wastewater treatment plant, and an urban river. Mortality rates of indicator microorganisms in sediment of an urban river were also measured. Mortality rates of indicator microorganisms in domestic sewage, estimated by assuming first order kinetics at 20 degrees C were 0.197 day(-1), 0.234 day(-1), 0.258 day(-1) and 0.276 day(-1) for total coliform, fecal coliform, Escherichia coli, and fecal streptococci, respectively. Effects of temperature, sunlight irradiation and settlement on the mortality rate were measured. Results of this research can be used as input data for water quality modeling or can be used as design factors for treatment facilities. PMID:20923108