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Sample records for agricultural headwater streams

  1. Conservation implications of amphibian habitat relationships within channelized agricultural headwater streams in the midwestern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The widespread use of stream channelization and subsurface tile drainage for removing water from agricultural fields has led to the development of numerous channelized agricultural headwater streams within agricultural watersheds of the Midwestern United States. Channelized agricultural headwater s...

  2. Influence of instream habitat and water chemistry on amphibians within channelized agricultural headwater streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The widespread use of stream channelization and subsurface tile drainage for draining agricultural fields has led to the development of numerous channelized agricultural headwater streams within agricultural watersheds of the Midwestern United States, Canada, and Europe. Channelized agricultural he...

  3. Annual and seasonal differences in pesticide mixtures within channelized agricultural headwater streams in central Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Only a limited amount of information on pesticide mixtures within agricultural headwater streams is available. A greater understanding of the characteristics of pesticide mixtures and their spatial and temporal trends within agricultural headwater streams is needed to evaluate the risks of pesticid...

  4. Differences in instream wood characteristics between channelized and unchannelized agricultural headwater streams in central Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Instream wood is an important resource for stream biota because it provides cover for fishes, substrate for macroinvertebrates, and increases habitat diversity. However, current management of instream wood within channelized agricultural headwater streams (drainage ditches) involves removing instrea...

  5. The importance of instream habitat modifications for restoring channelized agricultural headwater streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Science based information on the influence of restoration practices on fishes within channelized agricultural headwater streams in the Midwestern United States is currently lacking. Understanding fish-habitat relationships and fish responses to specific restoration practices will provide informatio...

  6. Nitrate removal and denitrification in headwater agricultural streams of the Pacific Northwest

    EPA Science Inventory

    Headwater streams can serve as important sites for nitrogen (N) removal in watersheds. Here we examine the influence of agricultural streams on watershed N export in the Willamette River Basin of western Oregon, USA, a region with mixed agricultural, urban and forestry land uses...

  7. Relative influence of different habitat factors on creek chub population structure within channelized agricultural headwater streams in central Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Creek chubs (Semotilus atromaculatus) are commonly found within channelized agricultural headwater streams within the Midwestern United States. Understanding the relationships of this headwater fish species with different habitat factors will provide information that can assist with developing resto...

  8. Linking nitrogen management, seep chemistry, and stream water quality in two agricultural headwater watersheds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian seepage zones in headwater agricultural watersheds represent important sources of nitrate-nitrogen (NO3-N) to surface waters, often connecting N-rich groundwater systems to streams. In this study, we examined how NO3-N concentrations in seep and stream water were affected by NO3-N processin...

  9. Agriculture has changed the amount and composition of dissolved organic matter in Central European headwater streams.

    PubMed

    Graeber, Daniel; Gelbrecht, Jörg; Pusch, Martin T; Anlanger, Christine; von Schiller, Daniel

    2012-11-01

    Dissolved organic matter (DOM) is an important part of the global carbon cycle and significantly influences aquatic ecosystem functions. Recent studies suggest that its amount and composition in freshwaters may be altered by agricultural land use, whereby the influence of preceding in-stream production and processing is not clear. To assess the land use effect on DOM amount and composition for the export from terrestrial to freshwater systems at the land-water interface, we sampled headwater streams draining agricultural and near-pristine catchments (forested and wetland) in the North German plains. To account for spatial and seasonal variation, we conducted a screening of DOM amount (53 sites) and composition (42 sites), and conducted bi-weekly samplings to investigate seasonal variation at eight sites over one year. Concentrations of dissolved organic carbon (DOC) were significantly higher for agricultural and wetland catchments than for forested catchments. Moreover, DOC loads exhibited higher seasonal variation for agricultural and wetland catchments than for forested catchments, which was due to higher variation in discharge. Parallel Factor Analysis revealed that the composition of DOM in agricultural catchments was significantly different from the other studied catchment types, and was characterized by low redox state and high structural complexity. Moreover, a gradient from protein- to humic-like fluorescence significantly separated forested from agricultural and wetland catchments. The contribution of humic-like DOM was strongly and positively related to DOC concentration, suggesting a mechanistic coupling of both. The effects of land use on patterns of DOC concentration and DOM composition were consistent across seasons, implying that land use strongly regulates DOM export. Overall, this study clearly shows the seasonally independent importance of agricultural land use for the amount and composition of DOM fluxes from the terrestrial zone to surface

  10. Diurnal variation of dominant nitrate retention processes in an agricultural headwater stream

    NASA Astrophysics Data System (ADS)

    Schuetz, Tobias; Ryabenko, Evgenia; Stumpp, Christine

    2015-04-01

    Nitrate and ammonium are introduced by agricultural practice into the environment and are transformed and retained on their pathway through aquatic environments. In particular, biological transformation processes (i.e. microbial denitrification or ammonium oxidation and assimilation) are responsible for the largest part of nitrate removal, which are also crucial processes in headwater streams. It is well known, that most of the biological processes are influenced by available (solar) energy fluxes, temperatures and dissolved oxygen concentrations, which vary with time and space. However, looking at biogeochemical hot spots in the landscapes` hydrological interface, the stream and river network (e.g. stream sections with a high biological activity), the temporal variability of biological processes can be an important control on total nitrate export. In this study, we therefore identified most important diurnal time periods for nitrate retention in a 75 m impervious section of an agricultural headwater stream using oxygen saturation dynamics and nitrate isotopes. We regularly measured discharge, hydro-geochemical and climate parameters, as well as nitrate and water isotopes in grab samples at three locations along the reach. On average, we observed a decrease of 10% in nitrate concentration from up- to downstream, which was only caused by biological processes and not by dilution. Nitrate isotope analysis indicated distinct trends along the reach and with time of the day. Both nitrate assimilation and nitrification caused significant changes in nitrate isotope distribution in the early day. To explain the distinct observed process dynamics from the morning to the afternoon, we simulated net primary production (NEP) and respiration using the river metabolism model RIVERMETC with observed oxygen concentrations and water temperatures. Comparing the results with the observed nitrate dynamics, the short time period when NEP occurs (~10:30 -12:30) seems to be crucial for

  11. Influence of riparian seepage zones on nitrate variability in two agricultural headwater streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riparian seepage zones are one of the primary pathways of groundwater transport to headwater streams. While seeps have been recognized for their contributions to streamflow, there is little information on how seeps affect stream water quality. The objective of this study was to examine the influence...

  12. Public Health Perspectives of Channelized and Unchannelized Headwater Streams in Central Ohio: A Case Study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Headwater streams constitute the majority of watersheds in the United States and many headwater streams in the midwest have been channelized for agricultural drainage. Public health implications of water chemistry and aquatic macroinvertebrates within channelized and unchannelized headwater streams ...

  13. Watershed scale influence of pesticide reduction practices on pesticides and fishes within channelized agricultural headwater streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Implementation of pesticide reduction practices to reduce pesticide usage within agricultural watersheds has the potential to reduce pesticide concentrations within agricultural streams. The watershed scale influence of pesticide reduction practices on pesticides and the biota within agricultural he...

  14. Effects of exposure to agricultural drainage ditch water on survivorship, distribution, and abundnance of riffle beetles (Coleoptera: Elmidae) in headwater streams of the Cedar Creek watershed, Indiana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Riffle Beetles (Coleoptera: Elmidae) require very good water quality, mature streams with riffle habitat, and high dissolved oxygen content. As such, they prove to be good indicators of ecological health in agricultural headwater streams. We conducted static renewal aquatic bioassays using water fro...

  15. Relationship Between Watershed Land Use and Denitrification Enzyme Activity in Headwater Streams

    EPA Science Inventory

    Headwater streams are the dominant land-water interface across much of the landscape. Denitrification is an important ecological service provided by headwater streams. Anthropogenic inputs of N to terrestrial ecosystems largely result from agricultural practices. Animal agricultu...

  16. Influence of adding small instream wood on fishes and hydrology within channelized agricultural headwater streams in central Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large instream wood is well known for its importance in headwater streams because it promotes the development of pool habitat for fishes and provides them with cover from predators during the summer. However, little is known about the influence of small instream wood (diameter < 10 cm, length < 1 m...

  17. ASSESSING HEADWATER STREAMS: LINKING LANDSCAPES TO STREAM NETWORKS

    EPA Science Inventory

    Headwater streams represent a significant land-water boundary and drain 70-80% of the landscape. Headwater streams are vital components to drainage systems and are directly linked to our downstream rivers and lakes. However, alteration and loss of headwater streams have occurre...

  18. [Phosphorus Fractions and Release Risk in Surface Sediments of an Agricultural Headwater Stream System in Hefei Suburban, China].

    PubMed

    Pei, Ting-ting; Li, Ru-zhong; Gao, Su-di; Luo, Yue-ying

    2016-02-15

    A typical water system of agricultural headwater stream in Chaohu Lake basin was selected as the study area, and 17, 16, 14 and 13 surface sediments were collected from the four styles of stream, respectively, including ponds, branches, main channel and mainstream deep pools, in October 2014 (in autumn) and April 2015 (in spring). The forms and space-time variations of phosphorus in the sediments were analyzed. Clustering and variance analysis were conducted on the phosphorus forms data from the four styles of stream by means of multivariate statistical analyses. We quantified the phosphorus release risk (PSI) and identified the main impact factors of PSI via calculating the phosphorus sorption index (PSI) and the correlation analysis. The results showed that: (1) The contents of TP in the surface sediments ranged from 137.517 to 1709.229 mg x kg(-1) with an average value of 532. 245 mg x kg(-1), and the order of the average contents of phosphorus forms was IP (350.347 mg x kg(-1)) > OP (167.333 mg x kg(-1)) > Fe/Al-P ( 78. 869 mg x kg(-1)) > Ca-P (56.343 mg x kg(-1)) > Ex-P (6.609 mg x kg(-1)); (2) The contents of phosphorus forms had the same trend in all the four stream styles, which was deep pool > main channel > branch > pond; (3) In autumn, the deep pool and main channel were clustered into one class, while the pond and branch were clustered into the other class. In spring, branch, main channel and deep pool were clustered into the same class; (4) Variance analysis showed that the differences among the four stream styles were larger in autumn than in spring; (5) The PSI of the surface sediments ranged between 24.49 and 69.94 (mg x L(-1) x (100 g x micromol)(-1). The PSI in spring was lower than that in spring, indicating that phosphorus release risk of surface sediment was higher in spring than in autumn. (6) PSI had a significant negative correlation with Ex-P, IP and pH.

  19. Water Quality Response to Changes in Agricultural Land Use Practices at Headwater Streams in Georgia

    EPA Science Inventory

    Poorly managed agricultural watersheds may be one of the most important contributors to high levels of bacterial and sediment loadings in surface waters. We investigated two cattle farms with differing management schemes to compare how physicochemical and meteorological parameter...

  20. Estimating the Regional Flux of Nitrate and Agricultural Herbicide Compounds from Groundwater to Headwater Streams of the Northern Atlantic Coastal Plain, USA

    NASA Astrophysics Data System (ADS)

    Ator, S.; Denver, J. M.

    2011-12-01

    Agriculture is common in the Northern Atlantic Coastal Plain (NACP, including New Jersey through North Carolina), and groundwater discharge provides nitrogen (primarily in the form of nitrate) and herbicide compounds from agricultural sources along with the majority of flow to NACP streams. Poor water quality has contributed to ecological degradation of tidal streams and estuaries along much of the adjacent mid-Atlantic coast. Although statistical models have provided estimates of total instream nutrient flux in the Coastal Plain, the regional flux of nitrogen and herbicides during base flow is less well understood. We estimated the regional flux of nitrate and selected commonly used herbicide compounds from groundwater to non-tidal headwater streams of the NACP on the basis of late-winter or spring base-flow samples from 174 such streams. Sampled streams were selected using an unequal-probability random approach, and flux estimates are based on resulting population estimates rather than empirical models, which are commonly used for such estimates. Base-flow flux in the estimated 8,834 NACP non-tidal headwater streams are an estimated 21,200 kilograms per day of nitrate (as N) and 5.83, 0.565, and 20.7 kilograms per day of alachlor, atrazine, and metolachlor (including selected degradates), respectively. Base-flow flux of alachlor and metolachlor is dominated by degradates; flux of parent compounds is less than 3 percent of the total flux of parent plus degradates. Base-flow flux of nitrate and herbicides as a percentage of applications generally varies predictably with regional variations in hydrogeology. Abundant nonpoint (primarily agricultural) sources and hydrogeologic conditions, for example, contribute to particularly large base-flow flux from the Delmarva Peninsula to Chesapeake Bay. In the Delmarva Peninsula part of the Chesapeake Watershed, more than 10 percent of total nonpoint nitrogen applications is transported through groundwater to stream base flow

  1. Influence of catchment land cover on stoichiometry and stable isotope compositions of basal resources and macroinvertebrate consumers in headwater streams

    EPA Science Inventory

    Anthropogenic land use affects aquatic landscapes. For example, landscape-level conversion to urban or agricultural land can heavily influence nutrient cycles in headwater streams via increased nutrient loading and altered hydrologic patterns. Recent studies in headwater streams ...

  2. Influence of grass filter strips on structure and function of riparian habitats of agricultural headwater streams in central Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grass filter strips are a widely used conservation practice in the United States for reducing nutrient, pesticide, and sediment loadings into agricultural streams. Previous studies have documented the effectiveness of grass filter strips in reducing the input of agricultural pollutants, but the inf...

  3. Characterizing hydrologic permanence in headwater streams

    EPA Science Inventory

    The presentation will be an overview of research to inform jurisdictional determinations for the Clean Water Act, in particular research that hydrographic comparisons of the extent and hydrologic permanence of headwater streams, indicator development, and an evaluation of a rapid...

  4. Influence of planting grass filter strips on the structure and function of riparian habitats of agricultural headwater streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grass filter strips are strips of cool or warm season grasses planted adjacent to agricultural streams to reduce nutrient, pesticide, and sediment input. This conservation practice is the most frequently planted riparian buffer type in the United States. Previous studies have not evaluated how gra...

  5. INDICATORS OF HYDROLOGIC PERMANENCE IN HEADWATER STREAMS

    EPA Science Inventory

    Headwater intermittent streams lie at the aquatic-terrestrial interface and represent much of our nation's stream miles. Recent court cases concerning the definition of jurisdictional waters under the Clean Water Act have illuminated a need to better understand the characteristi...

  6. ARE SALAMANDERS USEFUL INDICATORS OF HYDROLOGIC PERMANENCE IN HEADWATER STREAMS?

    EPA Science Inventory

    Regulatory agencies need appropriate indicators of stream permanence to aid in jurisdictional determinations for headwater streams. We evaluated salamanders as permanence indicators because they are often abundant in fishless headwaters. Salamander and habitat data were collect...

  7. Hydrologic connectivity and the contribution of stream headwaters to ecological integrity at regional scales

    USGS Publications Warehouse

    Freeman, Mary C.; Pringle, C.M.; Jackson, C.R.

    2007-01-01

    Cumulatively, headwater streams contribute to maintaining hydrologic connectivity and ecosystem integrity at regional scales. Hydrologic connectivity is the water-mediated transport of matter, energy and organisms within or between elements of the hydrologic cycle. Headwater streams compose over two-thirds of total stream length in a typical river drainage and directly connect the upland and riparian landscape to the rest of the stream ecosystem. Altering headwater streams, e.g., by channelization, diversion through pipes, impoundment and burial, modifies fluxes between uplands and downstream river segments and eliminates distinctive habitats. The large-scale ecological effects of altering headwaters are amplified by land uses that alter runoff and nutrient loads to streams, and by widespread dam construction on larger rivers (which frequently leaves free-flowing upstream portions of river systems essential to sustaining aquatic biodiversity). We discuss three examples of large-scale consequences of cumulative headwater alteration. Downstream eutrophication and coastal hypoxia result, in part, from agricultural practices that alter headwaters and wetlands while increasing nutrient runoff. Extensive headwater alteration is also expected to lower secondary productivity of river systems by reducing stream-system length and trophic subsidies to downstream river segments, affecting aquatic communities and terrestrial wildlife that utilize aquatic resources. Reduced viability of freshwater biota may occur with cumulative headwater alteration, including for species that occupy a range of stream sizes but for which headwater streams diversify the network of interconnected populations or enhance survival for particular life stages. Developing a more predictive understanding of ecological patterns that may emerge on regional scales as a result of headwater alterations will require studies focused on components and pathways that connect headwaters to river, coastal and

  8. Salamander occupancy in headwater stream networks

    USGS Publications Warehouse

    Grant, E.H.C.; Green, L.E.; Lowe, W.H.

    2009-01-01

    1. Stream ecosystems exhibit a highly consistent dendritic geometry in which linear habitat units intersect to create a hierarchical network of connected branches. 2. Ecological and life history traits of species living in streams, such as the potential for overland movement, may interact with this architecture to shape patterns of occupancy and response to disturbance. Specifically, large-scale habitat alteration that fragments stream networks and reduces connectivity may reduce the probability a stream is occupied by sensitive species, such as stream salamanders. 3. We collected habitat occupancy data on four species of stream salamanders in first-order (i.e. headwater) streams in undeveloped and urbanised regions of the eastern U.S.A. We then used an information-theoretic approach to test alternative models of salamander occupancy based on a priori predictions of the effects of network configuration, region and salamander life history. 4. Across all four species, we found that streams connected to other first-order streams had higher occupancy than those flowing directly into larger streams and rivers. For three of the four species, occupancy was lower in the urbanised region than in the undeveloped region. 5. These results demonstrate that the spatial configuration of stream networks within protected areas affects the occurrences of stream salamander species. We strongly encourage preservation of network connections between first-order streams in conservation planning and management decisions that may affect stream species.

  9. Effective discharge in Rocky Mountain headwater streams

    NASA Astrophysics Data System (ADS)

    Bunte, Kristin; Abt, Steven R.; Swingle, Kurt W.; Cenderelli, Dan A.

    2014-11-01

    Whereas effective discharge (Qeff) in mountain streams is commonly associated with a moderate flow such as bankfull discharge (Qbf), this study found that the maximum discharge (Qmax), and not bankfull discharge, is the channel forming or effective flow for gravel transport in plane-bed streams where partial bed mobility causes steep gravel transport rating curves. Qeff may approach bankfull flow in some step-pool channels where gravel moves over a static cobble/boulder bed. Our conclusions are based on magnitude-frequency analyses conducted at 41 gauged Rocky Mountain headwater streams. Because these gauged streams lacked gravel transport data, as is typical, comparable streams with measured transport rates were used to develop scaling relations for rating curve exponents with stream and watershed characteristics. Those scaling relations were then used to estimate the steepness of gravel rating curves at the 41 gauged but unsampled sites. The measured flow frequency distributions were characterized by two fitted power functions. The steepness of the flow frequency distributions and the estimated steepness of gravel transport relations were combined in magnitude-frequency analyses to compute Qeff.

  10. HEADWATER INTERMITTENT STREAMS STUDY: COLLABORATION ACROSS THE NATION

    EPA Science Inventory

    Headwater streams are the most abundant and widespread of our nation's surface waters, yet little guidance is available specific to these resources. Headwater streams lie at the terrestrial-aquatic interface, both spatially because of their narrow channels and landscape position ...

  11. Physical indicators of hydrologic permanence in forested headwater streams

    EPA Science Inventory

    Recent court cases have brought headwater streams and their hydrologic permanence into the forefront for regulatory agencies, so rapid field-based indicators of hydrologic permanence in streams are critically needed. Our study objectives were to 1) identify environmental charact...

  12. BIOLOGICAL INTEGRITY IN MID-ATLANTIC COASTAL PLAINS HEADWATER STREAMS

    EPA Science Inventory

    The objective of this study was to assess the applicability of landscape metrics, in conjunction with stream water quality to estimate the biological integrity of headwater streams in the Mid-Atlantic Coastal Plains using multivariate techniques.

  13. Where Did All the Streams Go? Effects of Urbanization on Hydrologic Permanence of Headwater Streams

    EPA Science Inventory

    Headwater streams represent a majority (up to 70%) of the stream length in the United States; however, these small streams are often piped or filled to accommodate residential, commercial, and industrial development. Legal protection of headwater streams under the Clean Water Ac...

  14. SCIENCE TO INFORM POLICY ON PROTECTION OF HEADWATER STREAMS

    EPA Science Inventory

    Recent court cases concerning the definition of jurisdictional waters under the Clean Water Act have illuminated a need to better understand characteristics and functions of headwater streams (and associated riparian and wetland habitats). Research is needed to better quantify 1...

  15. BIOLOGICAL INTEGRITY IN MID-ATLANTIC COASTAL PLAINS HEADWATER STREAMS

    EPA Science Inventory

    The objective of this study was to assess the applicability of using landscape variables in conjunction with water quality and benthic data to efficiently estimate stream condition of select headwater streams in the Mid-Atlantic Coastal Plains. Eighty-two streams with riffle sit...

  16. Dam removal increases American eel abundance in distant headwater streams

    USGS Publications Warehouse

    Hitt, Nathaniel P.; Eyler, Sheila; Wofford, John E.B.

    2012-01-01

    American eel Anguilla rostrata abundances have undergone significant declines over the last 50 years, and migration barriers have been recognized as a contributing cause. We evaluated eel abundances in headwater streams of Shenandoah National Park, Virginia, to compare sites before and after the removal of a large downstream dam in 2004 (Embrey Dam, Rappahannock River). Eel abundances in headwater streams increased significantly after the removal of Embrey Dam. Observed eel abundances after dam removal exceeded predictions derived from autoregressive models parameterized with data prior to dam removal. Mann–Kendall analyses also revealed consistent increases in eel abundances from 2004 to 2010 but inconsistent temporal trends before dam removal. Increasing eel numbers could not be attributed to changes in local physical habitat (i.e., mean stream depth or substrate size) or regional population dynamics (i.e., abundances in Maryland streams or Virginia estuaries). Dam removal was associated with decreasing minimum eel lengths in headwater streams, suggesting that the dam previously impeded migration of many small-bodied individuals (<300 mm TL). We hypothesize that restoring connectivity to headwater streams could increase eel population growth rates by increasing female eel numbers and fecundity. This study demonstrated that dams may influence eel abundances in headwater streams up to 150 river kilometers distant, and that dam removal may provide benefits for eel management and conservation at the landscape scale.

  17. Influence of instream habitat and water quality on aggressive behavior in crayfish of channelized headwater streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many agricultural drainage ditches that border farm fields of the Midwestern United States are degraded headwater streams that possess communities of crayfish. We hypothesized that crayfish communities at sites with low instream habitat diversity and poor water quality would show greater evidence of...

  18. Comparison of organic matter composition in agricultural versus forest affected headwaters with special emphasis on organic nitrogen.

    PubMed

    Heinz, Marlen; Graeber, Daniel; Zak, Dominik; Zwirnmann, Elke; Gelbrecht, Joerg; Pusch, Martin T

    2015-02-17

    Agricultural management practices promote organic matter (OM) turnover and thus alter both the processing of dissolved organic matter (DOM) in soils and presumably also the export of DOM to headwater streams, which intimately connect the terrestrial with the aquatic environment. Size-exclusion chromatography, in combination with absorbance and emission matrix fluorometry, was applied to assess how agricultural land use alters the amount and composition of DOM, as well as dissolved organic nitrogen (DON) forms in headwater streams, including temporal variations, in a temperate region of NE Germany. By comparing six agriculturally and six forest-impacted headwater streams, we demonstrated that agriculture promotes increased DOC and DON concentrations, entailing an even more pronounced effect on DON. The major part of DOC and DON in agricultural and forest reference streams is exported in the form of humic-like material with high molecular weight, which indicates terrestrial, i.e., allochthonous sources. As an obvious difference in agricultural streams, the contribution of DOC and particularly DON occurring in the form of nonhumic high-molecular-weight, presumably proteinous material is clearly elevated. Altogether, DOM in agricultural headwaters is mainly complex-soil-derived and aromatic material with a low C:N ratio, which is more microbial processed than its counterpart from forest reference catchments. Our results emphasize the importance of agricultural land use on DOM loss from soils and identify agricultural soils as important DOC and particularly DON sources to headwater streams.

  19. The Role of Headwater Streams in Downstream Water Quality.

    PubMed

    Alexander, Richard B; Boyer, Elizabeth W; Smith, Richard A; Schwarz, Gregory E; Moore, Richard B

    2007-02-01

    Knowledge of headwater influences on the water-quality and flow conditions of downstream waters is essential to water-resource management at all governmental levels; this includes recent court decisions on the jurisdiction of the Federal Clean Water Act (CWA) over upland areas that contribute to larger downstream water bodies. We review current watershed research and use a water-quality model to investigate headwater influences on downstream receiving waters. Our evaluations demonstrate the intrinsic connections of headwaters to landscape processes and downstream waters through their influence on the supply, transport, and fate of water and solutes in watersheds. Hydrological processes in headwater catchments control the recharge of subsurface water stores, flow paths, and residence times of water throughout landscapes. The dynamic coupling of hydrological and biogeochemical processes in upland streams further controls the chemical form, timing, and longitudinal distances of solute transport to downstream waters. We apply the spatially explicit, mass-balance watershed model SPARROW to consider transport and transformations of water and nutrients throughout stream networks in the northeastern United States. We simulate fluxes of nitrogen, a primary nutrient that is a water-quality concern for acidification of streams and lakes and eutrophication of coastal waters, and refine the model structure to include literature observations of nitrogen removal in streams and lakes. We quantify nitrogen transport from headwaters to downstream navigable waters, where headwaters are defined within the model as first-order, perennial streams that include flow and nitrogen contributions from smaller, intermittent and ephemeral streams. We find that first-order headwaters contribute approximately 70% of the mean-annual water volume and 65% of the nitrogen flux in second-order streams. Their contributions to mean water volume and nitrogen flux decline only marginally to about 55% and

  20. The Role of Headwater Streams in Downstream Water Quality1

    PubMed Central

    Alexander, Richard B; Boyer, Elizabeth W; Smith, Richard A; Schwarz, Gregory E; Moore, Richard B

    2007-01-01

    Knowledge of headwater influences on the water-quality and flow conditions of downstream waters is essential to water-resource management at all governmental levels; this includes recent court decisions on the jurisdiction of the Federal Clean Water Act (CWA) over upland areas that contribute to larger downstream water bodies. We review current watershed research and use a water-quality model to investigate headwater influences on downstream receiving waters. Our evaluations demonstrate the intrinsic connections of headwaters to landscape processes and downstream waters through their influence on the supply, transport, and fate of water and solutes in watersheds. Hydrological processes in headwater catchments control the recharge of subsurface water stores, flow paths, and residence times of water throughout landscapes. The dynamic coupling of hydrological and biogeochemical processes in upland streams further controls the chemical form, timing, and longitudinal distances of solute transport to downstream waters. We apply the spatially explicit, mass-balance watershed model SPARROW to consider transport and transformations of water and nutrients throughout stream networks in the northeastern United States. We simulate fluxes of nitrogen, a primary nutrient that is a water-quality concern for acidification of streams and lakes and eutrophication of coastal waters, and refine the model structure to include literature observations of nitrogen removal in streams and lakes. We quantify nitrogen transport from headwaters to downstream navigable waters, where headwaters are defined within the model as first-order, perennial streams that include flow and nitrogen contributions from smaller, intermittent and ephemeral streams. We find that first-order headwaters contribute approximately 70% of the mean-annual water volume and 65% of the nitrogen flux in second-order streams. Their contributions to mean water volume and nitrogen flux decline only marginally to about 55% and

  1. The role of headwater streams in downstream water quality

    USGS Publications Warehouse

    Alexander, R.B.; Boyer, E.W.; Smith, R.A.; Schwarz, G.E.; Moore, R.B.

    2007-01-01

    Knowledge of headwater influences on the water-quality and flow conditions of downstream waters is essential to water-resource management at all governmental levels; this includes recent court decisions on the jurisdiction of the Federal Clean Water Act (CWA) over upland areas that contribute to larger downstream water bodies. We review current watershed research and use a water-quality model to investigate headwater influences on downstream receiving waters. Our evaluations demonstrate the intrinsic connections of headwaters to landscape processes and downstream waters through their influence on the supply, transport, and fate of water and solutes in watersheds. Hydrological processes in headwater catchments control the recharge of subsurface water stores, flow paths, and residence times of water throughout landscapes. The dynamic coupling of hydrological and biogeochemical processes in upland streams further controls the chemical form, timing, and longitudinal distances of solute transport to downstream waters. We apply the spatially explicit, mass-balance watershed model SPARROW to consider transport and transformations of water and nutrients throughout stream networks in the northeastern United States. We simulate fluxes of nitrogen, a primary nutrient that is a water-quality concern for acidification of streams and lakes and eutrophication of coastal waters, and refine the model structure to include literature observations of nitrogen removal in streams and lakes. We quantify nitrogen transport from headwaters to downstream navigable waters, where headwaters are defined within the model as first-order, perennial streams that include flow and nitrogen contributions from smaller, intermittent and ephemeral streams. We find that first-order headwaters contribute approximately 70% of the mean-annual water volume and 65% of the nitrogen flux in second-order streams. Their contributions to mean water volume and nitrogen flux decline only marginally to about 55% and

  2. Influence of Herbaceous Riparian Buffers on Fish and Amphibian Communities Within Channelized Headwater Streams in Central Ohio

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Herbaceous riparian buffers are a widely used conservation practice in the United States for reducing nutrient, pesticide, and sediment loadings in agricultural streams. The importance of forested riparian zones for headwater streams has been documented, but the ecological impacts of herbaceous ripa...

  3. Hydrology and Geomorphology of Tallgrass Prairie Intermittent Headwater Streams

    NASA Astrophysics Data System (ADS)

    Daniels, M. D.; Grudzinski, B.

    2011-12-01

    The arid to semi-arid Great Plains region of the United States covers more than 1 million km2, yet virtually nothing is known about the geomorphology of its intermittent headwater streams. These streams and the perennial rivers they feed support a unique and increasingly endangered assemblage of endemic fish species. While human impacts in the region are not at first glace significant, the reality is that the Great Plains are an intensively managed landscape, with pervasive cattle grazing, channelization, and groundwater over-pumping affecting these systems. These stresses will only increase with potential climate and related land use changes. Few natural remnants of native grassland remain today, limiting opportunities to study the natural dynamics of these systems in contrast to the anthropogenically modified systems. This paper presents a review of the existing geomorphological and hydrological knowledge of Great Plains headwater streams and presents the initial analysis of an 18 year intermittent headwater stream record from the tallgrass Konza Prairie LTER, Kansas. Results suggest that fire frequency and grazing and the resultant riparian vegetation composition strongly influence stream flow dynamics as well as stream geomorphology.

  4. Contribution of a Headwater Stream to the Global Carbon Budget

    NASA Astrophysics Data System (ADS)

    Argerich, A.; Johnson, S. L.; Haggerty, R.; Dosch, N.; Corson-Rikert, H.; Ashkenas, L.; Pennington, R.; Wondzell, S. M.

    2014-12-01

    The carbon cycle has been subject of numerous studies in recent years, primarily due to the role of CO2 and CH4 in global warming. Understanding the components and processes contributing to the global carbon cycle across a landscape is essential to understand climate change drivers and predicting future climate. Although the role of streams and rivers in transporting and processing nutrients from the land to the ocean has been widely recognized, most climate models still consider riverine systems as mere conduits without processing capacity. Evasion of carbon dioxide from inland waters has only been recently acknowledged to be an important source of carbon to the atmosphere and still, these estimations don't take into account evasion from headwater streams due to a lack of data. Here we present a 10-year C budget for a small headwater stream draining a 96-ha watershed in western Oregon, USA. This stream exported ~5000 g C per m2 of stream area, approximately 9% of the ecosystem production of the catchment (NEP). Export is dominated by evasion of CO2 to the atmosphere (~2200 g C per m2/y) and by downstream transport of dissolved inorganic carbon (DIC, ~1300 g per m2/y). Although highest in-stream pCO2 and DIC concentrations happen during summer low-flows, most stream export happens during winter high flows indicating at least a seasonal lag between CO2 production (i.e., respiration) and carbon export.

  5. Comprehensive multiyear carbon budget of a temperate headwater stream

    NASA Astrophysics Data System (ADS)

    Argerich, Alba; Haggerty, Roy; Johnson, Sherri L.; Wondzell, Steven M.; Dosch, Nicholas; Corson-Rikert, Hayley; Ashkenas, Linda R.; Pennington, Robert; Thomas, Christoph K.

    2016-05-01

    Headwater streams comprise nearly 90% of the total length of perennial channels in global catchments. They mineralize organic carbon entering from terrestrial systems, evade terrestrial carbon dioxide (CO2), and generate and remove carbon through in-stream primary production and respiration. Despite their importance, headwater streams are often neglected in global carbon budgets primarily because of a lack of available data. We measured these processes, in detail, over a 10 year period in a stream draining a 96 ha forested watershed in western Oregon, USA. This stream, which represents only 0.4% of the watershed area, exported 159 kg C ha-1 yr-1, similar to the global exports for large rivers. Stream export was dominated by downstream transport of dissolved inorganic carbon (63 kg C ha-1 yr-1) and by evasion of CO2 to the atmosphere (42 kg C ha-1 yr-1), leaving the remainder of 51 kg C ha-1 yr-1 for downstream transport of organic carbon (17 kg C ha-1 yr-1 and 34 kg C ha-1 yr-1 in dissolved and particulate form, respectively).

  6. Turbidity Dynamics in an Urbanized Headwater Stream

    NASA Astrophysics Data System (ADS)

    Wynn, T. M.; Utley, B. C.; Davis, K.; Simpson, J. A.

    2008-12-01

    Excess suspended sediment in streams degrades aquatic ecosystems, reduces reservoir capacity, increases drinking water treatment costs, and serves as a carrier for pollutants such as phosphorus, bacterial, heavy metals, and pesticides. Due to the high temporal variability of suspended sediment transport, continuous instream turbidity measurements are used as a surrogate for suspended sediment concentration. This variability is particularly pronounced in small urban streams (drainage areas < 100 sq. km). To evaluate turbidity dynamics within the Stroubles Creek watershed (14 sq. km), two Eureka Manta multi-parameter sondes with McVan wiped turbidity sensors were installed at two cross sections upstream and downstream of a 450-m reach experiencing active bank retreat. Turbidity was recorded every 10 min. from March 2006 to May 2007. The continuous turbidity records were evaluated for hysteresis and indications of contributions of bank retreat to the stream sediment load. While the transport of suspended sediment from upstream sources through the study reach is observed, channel erosion appears to be a significant source of sediment to the stream.

  7. IMPACTS OF LAND USE ON HYDROLOGIC FLOW PERMANENCE IN HEADWATER STREAMS

    EPA Science Inventory

    Extensive urbanization in the watershed can alter the stream hydrology by increasing peak runoff frequency and reducing base flows, causing subsequent impairment of stream community structure. In addition, development effectively eliminates some headwater streams, being piped an...

  8. Predicting alpine headwater stream intermittency: a case study in the northern Rocky Mountains

    USGS Publications Warehouse

    Sando, Thomas R.; Blasch, Kyle W.

    2015-01-01

    This investigation used climatic, geological, and environmental data coupled with observational stream intermittency data to predict alpine headwater stream intermittency. Prediction was made using a random forest classification model. Results showed that the most important variables in the prediction model were snowpack persistence, represented by average snow extent from March through July, mean annual mean monthly minimum temperature, and surface geology types. For stream catchments with intermittent headwater streams, snowpack, on average, persisted until early June, whereas for stream catchments with perennial headwater streams, snowpack, on average, persisted until early July. Additionally, on average, stream catchments with intermittent headwater streams were about 0.7 °C warmer than stream catchments with perennial headwater streams. Finally, headwater stream catchments primarily underlain by coarse, permeable sediment are significantly more likely to have intermittent headwater streams than those primarily underlain by impermeable bedrock. Comparison of the predicted streamflow classification with observed stream status indicated a four percent classification error for first-order streams and a 21 percent classification error for all stream orders in the study area.

  9. Are Salamanders Useful Indicators of Hydrologic Permanence in Headwater Streams?

    NASA Astrophysics Data System (ADS)

    Johnson, B.; Fritz, K.

    2005-05-01

    Regulatory agencies need appropriate indicators of stream permanence to aid in jurisdictional determinations for headwater streams. We evaluated salamanders as permanence indicators because they are often abundant in fishless headwaters. Salamander and habitat data were collected in spring and summer 2003 from 59 sites located longitudinally along 17 forested streams in KY, IN, and OH. Larval Eurycea bislineata/cirrigera dominated all forests, and their abundances were highly correlated with drainage areas and channel dimensions. Appalachian streams were more diverse and had intermittent sites with more Desmognathus and Gyrinophilus spp. Of 22 sites where larvae were collected in spring, 9 sites subsequently dried in summer, suggesting salamanders either emigrated or died. We therefore only used taxa with multi-year larval stages as indicators of perennial water. Salamander larvae >1 yr old were collected from each locality in drainage areas <0.17 km2. However, these older larvae were often found in isolated pools that serve as refugia during dry periods. Findings suggest salamanders with multi-year larval periods can indicate perennial waters and that their use is more effective in Appalachia where abundance and diversity are high. Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official Agency policy.

  10. Headwater Streams in Porous Landscapes - What's the contributing area?

    NASA Astrophysics Data System (ADS)

    Jackson, C. R.; Bitew, M. M.; Du, E.; Griffiths, N.; Hopp, L.; Klaus, J.; McDonnell, J.; Vache, K. B.

    2015-12-01

    Building on a long legacy of hydrogeological investigations at the Savannah River Site in the Sandhills of the Upper Coastal Plain in South Carolina, we began in 2005 a headwater-scale investigation of hillslope flow pathways, streamflow sources, and water quality responses to intensive woody biomass production. The landscape is characterized by blackwater streams flowing slowly through wide flat stream valleys, deep unconsolidated layers of sands and clays, a regional clay layer beneath Fourmile Creek that defines the lower boundary of the surficial aquifer, rolling topography with steeper slopes on the valley margins and gentle slopes elsewhere, and a sandy clay loam argillic layer within 0.2 to 1.5m from the surface. Most water leaves headwater basins by groundwater flow, appearing as streamflow far downstream. Only at scales larger than 50 km2 does average streamflow match expectations from water balances. This raises the question, what constitutes the contributing area for headwater streams in porous landscapes? Perching and interflow generation over the argillic horizon is common, but leakage through clay is rapid relative to interflow travel times, so interflow serves to shift the point of percolation downslope from the point of infiltration. Only interflow from the valley-adjacent slopes can contribute to stormflow responses. Our interflow interception trenches and maximum rise piezometer networks reveal high heterogeneity in subsurface flow paths at multiple spatial scales. Streamwater has isotopic and chemical characteristics similar to deep groundwater, but we cannot easily determine the source area for groundwater reaching the first order streams. Our observations suggest that one's view of hillslope and catchment flow processes depends on the scale, number, and frequency of observations of state variables and outputs. In some cases, less frequent or less numerous observations of fewer tracers would have yielded different inferences. The data also

  11. Ecoregion and land-use influence invertebrate and detritus transport from headwater streams

    USGS Publications Warehouse

    Binckley, Christopher A.; Wipfli, Mark S.; Medhurst, R. Bruce; Polivka, Karl; Hessburg, Paul F.; Salter, R. Brion; Kill, Joshua Y.

    2010-01-01

    4. Understanding the quantity and variation of headwater subsidies across climate and disturbance gradients is needed to appreciate the significance of ecological linkages between headwaters and associated downstream habitats. This will enable the accurate assessment of resource management impacts on stream ecosystems. Predicting the consequences of natural and anthropogenic disturbances on headwater stream transport rates will require knowledge of how both local and regional factors influence these potential subsidies. Our results suggest that resources transported from headwater streams reflect both the meso-scale land-use surrounding these areas and the constraints imposed by the ecoregion in which they are embedded.

  12. Forested headwaters mitigate pesticide effects on macroinvertebrate communities in streams: Mechanisms and quantification.

    PubMed

    Orlinskiy, Polina; Münze, Ronald; Beketov, Mikhail; Gunold, Roman; Paschke, Albrecht; Knillmann, Saskia; Liess, Matthias

    2015-08-15

    Pesticides impact invertebrate communities in freshwater ecosystems, leading to the loss of biodiversity and ecosystem functions. One approach to reduce such effects is to maintain uncontaminated stream reaches that can foster recovery of the impacted populations. We assessed the potential of uncontaminated forested headwaters to mitigate pesticide impact on the downstream macroinvertebrate communities in 37 streams, using the SPEARpesticides index. Pesticide contamination was measured with runoff-triggered techniques and Chemcatcher® passive samplers. The data originated from 3 field studies conducted between 1998 and 2011. The proportion of vulnerable species decreased significantly after pesticide exposure even at low toxicity levels (-4stream section (0.2-18 km), whereas other characteristics of the forest or abiotic water parameters did not have an effect within the measured gradients. The presence of forested headwaters was not associated with reduced pesticide exposure 3 km downstream and did not reduce the loss of vulnerable taxa after exposure. Nevertheless, forested headwaters were associated with the absence of long-term pesticide effects on the macroinvertebrate community composition. We conclude that although pesticides can cause the loss of vulnerable aquatic invertebrates even at low toxicity levels, forested headwaters enhance the recovery of vulnerable species in agricultural landscapes.

  13. Seasonal nitrate uptake and denitrification potential in small headwater streams in the Willamette Valley, Oregon

    EPA Science Inventory

    Background/Question/Methods Headwater streams can serve as important sources and sinks for nitrogen (N) for downstream receiving waters. Prior research on N removal in small streams has largely focused on growing season conditions. Here we examine the influence of headwater...

  14. DEVELOPMENT OF BIOLOGICAL INDICATORS, METHODS AND ASSESSMENT TECHNIQUES FOR USE IN HEADWATER INTERMITTENT STREAMS

    EPA Science Inventory

    Despite representing the most abundant and widespread of our nation's surface waters, regions, states and tribes have received little guidance specific to headwater intermittent streams from the U.S. EPA. Headwater streams lie at the terrestrial-aquatic interface both spatially,...

  15. Controls on scaling relationships of dynamic headwater stream networks

    NASA Astrophysics Data System (ADS)

    Godsey, S.; Kirchner, J. W.; Whiting, J. A.

    2013-12-01

    Stream networks expand and contract within their channel network, particularly within their headwaters. Along their length, especially during drought periods, it is not unusual to encounter dry reaches of varying lengths. Controls on the length and location of those dry reaches include: large woody debris, upstream sediment loading, hydraulic properties of the subsurface/hyporheic zone, and the catchment hydroclimate and morphology. Here we examine patterns in the length of discontinuous reaches, their location, and the length of the overall drainage network. We find that drainage networks expand with discharge as a power-law relationship with a slope of ~0.25, contradicting recent theoretical suggestions in the literature that this scaling exponent should be close to 1.0. We discuss physical limitations on the range of potential scaling relationships, and link stream responses to groundwater and evapotranspiration sources and sinks.

  16. Macroinvertebrate and organic matter export from headwater tributaries of a Central Appalachian stream

    EPA Science Inventory

    Headwater streams export organisms and other materials to their receiving streams and macroinvertebrate drift can shape colonization dynamics in downstream reaches while providing food for downstream consumers. Spring-time macroinvertebrate drift and organic matter export was me...

  17. Larval salamanders and channel geomorphology are indicators of hydrologic permanence in forested headwater streams

    EPA Science Inventory

    Regulatory agencies need rapid indicators of hydrologic permanence for jurisdictional determinations of headwater streams. Our study objective was to assess the utility of larval salamander presence and assemblage structure and habitat variables for determining stream permanence ...

  18. Urbanization Affects the Extent and Hydrologic Permanence of Headwater Streams in a Midwestern US Metropolitan Area

    EPA Science Inventory

    Headwater streams dominate natural landscapes and provide essential functions for downstream waters. However, because of minimal legal protection, they often are piped or buried to accommodate urban growth. Urbanization also alters stream base flows. The combined impact of these ...

  19. Characterization and classification of invertebrates as indicators of flow permanence in headwater streams

    EPA Science Inventory

    Headwater streams represent a large proportion of river networks and many have temporary flow. Litigation has questioned whether these streams are jurisdictional under the Clean Water Act. Our goal was to identify indicators of flow permanence by comparing invertebrate assemblage...

  20. Seasonal Sources of Carbon Exports in a Headwater Stream

    NASA Astrophysics Data System (ADS)

    Argerich, A.; Johnson, S. L.

    2013-12-01

    Climate change is intimately tied to changes in carbon (C) budgets. Understanding the compartments and processes involved in the global C cycle across a landscape is essential to predict future climate change scenarios. While most C budgets focus on terrestrial contributions, river systems contribute to the C cycle by the export of total organic carbon (TOC) and dissolved inorganic carbon (DIC) to the ocean and by exporting CO2 to the atmosphere. Although headwater streams constitute between 60 and 80 percent of fluvial systems their role in the C cycle has often been neglected due to the methodological constrains derived from their heterogeneous morphology. Here we present an analysis of the temporal variation of C export both downstream and evaded to the atmosphere for a headwater stream draining a forested watershed. We relate it to in-stream metabolic processes (respiration and primary production) and to different carbon pools. Specifically, we estimate downstream exports of C in the form of dissolved organic (DOC), dissolved inorganic (DIC), and particulate organic (POC); we estimate the C content in the fine benthic organic matter (FBOM), dead wood, algae, and macroinvertebrate pools; and finally, the amount of CO2 originated and fixed by stream respiration and primary production. Organic exports, both particulate and dissolved, represented 39.7% of the annual downstream export of C while dissolved inorganic C represented 60.3%. Higher exports were observed during periods of high flow (late fall and winter). Highest seasonality in downstream exports was observed for POC (89.5% coefficient of variation in mean monthly fluxes), followed by DOC and DIC (24.3% and 15.9% respectively). Dissolved CO2 had mostly an autochthonous origin during summer (i.e. from stream ecosystem respiration) and originated from allochthonous sources during the rain-dominated months in Oregon (late fall and winter). The stream was net heterotrophic and the amount of C cycled through

  1. Physical and temporal isolation of mountain headwater streams in the western Mojave Desert, Southern California

    USGS Publications Warehouse

    Izbicki, J.A.

    2007-01-01

    Streams draining mountain headwater areas of the western Mojave Desert are commonly physically isolated from downstream hydrologic systems such as springs, playa lakes, wetlands, or larger streams and rivers by stream reaches that are dry much of the time. The physical isolation of surface flow in these streams may be broken for brief periods after rainfall or snowmelt when runoff is sufficient to allow flow along the entire stream reach. Despite the physical isolation of surface flow in these streams, they are an integral part of the hydrologic cycle. Water infiltrated from headwater streams moves through the unsaturated zone to recharge the underlying ground-water system and eventually discharges to support springs, streamflow, isolated wetlands, or native vegetation. Water movement through thick unsaturated zones may require several hundred years and subsequent movement through the underlying ground-water systems may require many thousands of years - contributing to the temporal isolation of mountain headwater streams. ?? 2007 American Water Resources Association.

  2. Use of spatially explicit physicochemical data to measure downstream impacts of headwater stream disturbance

    EPA Science Inventory

    Regulatory agencies need methods to quantify the influence of headwater streams on downstream water quality as a result of litigation surrounding jurisdictional criteria and the influence of mountaintop removal coal mining activities. We collected comprehensive, spatially-referen...

  3. Can bryophytes be used to characterize hydrologic permanence in forested headwater streams?

    EPA Science Inventory

    Recent court cases have questioned whether all headwater streams, particularly those that are not perennial, fall within the protective boundaries of the Clean Water Act. Rapid field-based indicators of hydrologic permanence are critically needed for jurisdictional determination...

  4. Importance of environmental factors on the richness and distribution of benthic macroinvertebrates in tropical headwater streams

    EPA Science Inventory

    It is essential to understand the interactions between local environmental factors (e.g., physical habitat and water quality) and aquatic assemblages to conserve biodiversity in tropical and subtropical headwater streams. Therefore, we evaluated the relative importance of multipl...

  5. Influence of forest management on headwater stream amphibians at multiple spatial scales

    USGS Publications Warehouse

    Stoddard, Margo; Hayes, John P.; Erickson, Janet L.

    2004-01-01

    Background Amphibians are important components of headwater streams in forest ecosystems of the Pacific Northwest (PNW). They comprise the highest vertebrate biomass and density in these systems and are integral to trophic dynamics both as prey and as predators. The most commonly encountered amphibians in PNW headwater streams include the Pacific giant salamander (Dicamptodon tenebrosus), the tailed frog (Ascaphus truei), the southern torrent salamander (Rhyacotriton variegatus), and the Columbia torrent salamander (R. kezeri).

  6. The burial of headwater streams in drainage pipes reduces in-stream nitrate retention: results from two US metropolitan areas

    EPA Science Inventory

    Nitrogen (N) retention in stream networks is an important ecosystem service that may be affected by the widespread burial of headwater streams in urban watersheds. Stream burial occurs when segments of a channel are encased in drainage pipe and buried beneath the land surface to...

  7. Burial affects the biogeochemistry of headwater streams in a midwestern US metropolitan area

    EPA Science Inventory

    Nitrogen (N) retention in stream networks is an important ecosystem service that may be affected by the widespread burial of headwater streams in urban basins. Urban stream burial has only recently been recognized by ecologists and little research has addressed the extent to whi...

  8. Burial affects the biogeochemistry of headwater streams in a midwestern US metropolitan area - slides

    EPA Science Inventory

    Nitrogen (N) retention in stream networks is an important ecosystem service that may be affected by the widespread burial of headwater streams in urban basins. Urban stream burial has only recently been recognized by ecologists as a regional environmental impact and little resea...

  9. Aquatic insect assemblages associated with subalpine stream segment types in relict glaciated headwaters

    USGS Publications Warehouse

    Kubo, Joshua S.; Torgersen, Christian E.; Bolton, Susan M.; Weekes, Anne A.; Gara, Robert I.

    2013-01-01

    1. Aquatic habitats and biotic assemblages in subalpine headwaters are sensitive to climate and human impacts. Understanding biotic responses to such perturbations and the contribution of high-elevation headwaters to riverine biodiversity requires the assessment of assemblage composition among habitat types. We compared aquatic insect assemblages among headwater stream segment types in relict glaciated subalpine basins in Mt. Rainier National Park, Washington, USA. 2. Aquatic insects were collected during summer and autumn in three headwater basins. In each basin, three different stream segment types were sampled: colluvial groundwater sources, alluvial lake inlets, and cascade-bedrock lake outlets. Ward's hierarchical cluster analysis revealed high β diversity in aquatic insect assemblages, and non-metric multidimensional scaling indicated that spatial and temporal patterns in assemblage composition differed among headwater stream segment types. Aquatic insect assemblages showed more fidelity to stream segment types than to individual basins, and the principal environmental variables associated with assemblage structure were temperature and substrate. 3. Indicator species analyses identified specific aquatic insects associated with each stream segment type. Several rare and potentially endemic aquatic insect taxa were present, including the recently described species, Lednia borealis (Baumann and Kondratieff). 4. Our results indicate that aquatic insect assemblages in relict glaciated subalpine headwaters were strongly differentiated among stream segment types. These results illustrate the contribution of headwaters to riverine biodiversity and emphasise the importance of these habitats for monitoring biotic responses to climate change. Monitoring biotic assemblages in high-elevation headwaters is needed to prevent the potential loss of unique and sensitive biota.

  10. Sources of hydroxyl radical in headwater streams from nitrogen-saturated forest.

    PubMed

    Chiwa, Masaaki; Higashi, Naoko; Otsuki, Kyoichi; Kodama, Hiroki; Miyajima, Tohru; Takeda, Kazuhiko; Sakugawa, Hiroshi

    2015-01-01

    Hydroxyl radical (HO) photoformation rate (RHO) was determined in headwater stream samples from nitrogen (N)-saturated forests, (1) to quantify the sources of HO in headwater streams and (2) to evaluate the nitrate NO3(-)-induced enhancement of HO formation in stream water caused by N saturation in forested watersheds. Stream water fulvic acid extracted from the forested watersheds was used to quantify the contribution of dissolved organic matter (DOM) to RHO. The results showed that almost all (97%; 81-109%) RHO sources in our headwater stream samples were quantitatively elucidated; the photolysis of NO3(-) (55%; 34-75%), nitrite [N(III)] (2%; 0.5-5.2%), and DOM-derived HO formation, from which photo-Fenton reactions (18%; 12-26%) and the direct photolysis of fluorescent dissolved organic matter (FDOM) (22%; 10-40%), was successfully separated. FDOM, which accounted for 53% (24-96%) of DOM in total organic carbon bases, was responsible for HO formation in our headwater streams. High NO3(-) leaching caused by N saturation in forested watersheds increased RHO in the headwaters, indicating that N-saturated forest could significantly change photoinduced and biogeochemical processes via enhanced HO formation in downstream water.

  11. Landscape influences on headwater streams on Fort Stewart, Georgia, USA

    SciTech Connect

    Jager, Yetta; Bevelhimer, Mark S; al., et.

    2011-01-01

    Military landscapes represent a mixture of undisturbed natural ecosystems, developed areas, and lands that support different types and intensities of military training. Research to understand water-quality influences of military landscapes usually involves intensive sampling in a few watersheds. In this study, we developed a survey design of accessible headwater watersheds intended to improve our ability to distinguish land water relationships in general, and training influences, in particular, on Fort Stewart, GA. We sampled and analyzed water from watershed outlets. We successfully developed correlative models for total suspended solids (TSS), total nitrogen (TN), organic carbon (OC), and organic nitrogen (ON), which dominated in this blackwater ecosystem. TSS tended to be greater in samples after rainfall and during the growing season, and models that included %Wetland suggested a build-and-flush relationship. We also detected a positive association between TSS and tank-training, which suggests a need to intercept sediment-laden runoff from training areas. Models for OC showed a negative association with %Grassland. TN and ON both showed negative associations with %Grassland, %Wetland, and %Forest. Unexpected positive associations were observed between OC and equipmenttraining activity and between ON and %Bare ground ? Roads. Future studies that combine our survey-based approach with more intensive monitoring of the timing and intensity of training would be needed to better understand the mechanisms for these empirical relationships involving military training. Looking beyond local effects on Fort Stewart streams, we explore questions about how exports of OC and nitrogen from coastal military installations ultimately influence estuaries downstream.

  12. Riparian and in-stream controls on nutrient concentrations and fluxes in a headwater forested stream

    NASA Astrophysics Data System (ADS)

    Bernal, S.; Lupon, A.; Ribot, M.; Sabater, F.; Martí, E.

    2015-03-01

    Headwater streams are recipients of water sources draining through terrestrial ecosystems. At the same time, stream biota can transform and retain nutrients dissolved in stream water. Yet studies considering simultaneously these two sources of variation in stream nutrient chemistry are rare. To fill this gap of knowledge, we analyzed stream water and riparian groundwater concentrations and fluxes as well as in-stream net uptake rates for nitrate (NO3-), ammonium (NH4+), and soluble reactive phosphorus (SRP) along a 3.7 km reach on an annual basis. Chloride concentrations (used as conservative tracer) indicated a strong hydrological connection at the riparian-stream interface. However, stream and riparian groundwater nutrient concentrations showed a moderate to null correlation, suggesting high in-stream biogeochemical processing. In-stream net nutrient uptake (Fsw) was highly variable across contiguous segments and over time, but its temporal variation was not related to the vegetative period of the riparian forest. For NH4+, the occurrence of Fsw > 0 μg N m-1 s-1 (gross uptake > release) was high along the reach, while for NO3-, the occurrence of Fsw < 0 μg N m-1 s-1 (gross uptake < release) increased along the reach. Within segments and dates, Fsw, whether negative or positive, accounted for a median of 6, 18, and 20% of the inputs of NO3-, NH4+, and SRP, respectively. Whole-reach mass balance calculations indicated that in-stream net uptake reduced stream NH4+ flux up to 90%, while the stream acted mostly as a source of NO3- and SRP. During the dormant period, concentrations decreased along the reach for NO3-, but increased for NH4+ and SRP. During the vegetative period, NH4+ decreased, SRP increased, and NO3- showed a U-shaped pattern along the reach. These longitudinal trends resulted from the combination of hydrological mixing with terrestrial inputs and in-stream nutrient processing. Therefore, the assessment of these two sources of variation in stream

  13. Are bryophytes useful indicators of hydrologic permanence in forested headwater streams?

    EPA Science Inventory

    Court cases have recently questioned whether all headwater streams, particularly non-perennial streams, should be protected in the U.S. under the Clean Water Act. Rapid field-based indicators of hydrologic permanence are needed for jurisdictional determinations. The study objecti...

  14. Significance of headwater streams and perennial springs in ecological monitoring in Shenandoah National Park

    USGS Publications Warehouse

    Snyder, Craig D.; Webb, James R.; Young, John A.; Johnson, Zane B.

    2013-01-01

    Shenandoah National Park has been monitoring water chemistry and benthic macroinvertebrates in stream ecosystems since 1979. These monitoring efforts were designed to assess the status and trends in stream condition associated with atmospheric deposition (acid rain) and changes in forest health due to gypsy moth infestations. The primary objective of the present research was to determine whether the current long-term macroinvertebrate and water-quality monitoring program in Shenandoah National Park was failing to capture important information on the status and trends in stream condition by not sufficiently representing smaller, headwater streams. The current benthic-macroinvertebrate and water-chemistry sampling designs do not include routine collection of data from streams with contributing watershed areas smaller than 100 hectares, even though these small streams represent the overwhelming proportion of total stream length in the park. In this study, we sampled headwater sites, including headwater stream reaches (contributing watershed area approximately 100 hectares (ha) and perennial springs, in the park for aquatic macroinvertebrates and water chemistry and compared the results with current and historical data collected at long-term ecological monitoring (LTEM) sites on larger streams routinely sampled as part of ongoing monitoring efforts. The larger purpose of the study was to inform ongoing efforts by park managers to evaluate the effectiveness and efficiency of the current aquatic monitoring program in light of other potential stressors (for example, climate change) and limited resources. Our results revealed several important findings that could influence management decisions regarding long-term monitoring of park streams. First, we found that biological indicators of stream condition at headwater sites and perennial springs generally were more indicative of lower habitat quality and were more spatially variable than those observed at sites on routinely

  15. Predicting fine-scale distributions of peripheral aquatic species in headwater streams

    USGS Publications Warehouse

    DeRolph, Christopher R.; Nelson, S.; Kwak, Thomas J.; Hain, Ernie F.

    2015-01-01

    Headwater species and peripheral populations that occupy habitat at the edge of a species range may hold an increased conservation value to managers due to their potential to maximize intraspecies diversity and species' adaptive capabilities in the context of rapid environmental change. The southern Appalachian Mountains are the southern extent of the geographic range of native Salvelinus fontinalis and naturalized Oncorhynchus mykiss and Salmo trutta in eastern North America. We predicted distributions of these peripheral, headwater wild trout populations at a fine scale to serve as a planning and management tool for resource managers to maximize resistance and resilience of these populations in the face of anthropogenic stressors. We developed correlative logistic regression models to predict occurrence of brook trout, rainbow trout, and brown trout for every interconfluence stream reach in the study area. A stream network was generated to capture a more consistent representation of headwater streams. Each of the final models had four significant metrics in common: stream order, fragmentation, precipitation, and land cover. Strahler stream order was found to be the most influential variable in two of the three final models and the second most influential variable in the other model. Greater than 70% presence accuracy was achieved for all three models. The underrepresentation of headwater streams in commonly used hydrography datasets is an important consideration that warrants close examination when forecasting headwater species distributions and range estimates. Additionally, it appears that a relative watershed position metric (e.g., stream order) is an important surrogate variable (even when elevation is included) for biotic interactions across the landscape in areas where headwater species distributions are influenced by topographical gradients.

  16. Predicting fine-scale distributions of peripheral aquatic species in headwater streams

    SciTech Connect

    DeRolph, Christopher R.; Nelson, Stacy A. C.; Kwak, Thomas J.; Hain, Ernie F.

    2014-12-09

    Headwater species and peripheral populations that occupy habitat at the edge of a species range may hold an increased conservation value to managers due to their potential to maximize intraspecies diversity and species' adaptive capabilities in the context of rapid environmental change. The southern Appalachian Mountains are the southern extent of the geographic range of native Salvelinus fontinalis and naturalized Oncorhynchus mykiss and Salmo trutta in eastern North America. In this paper, we predicted distributions of these peripheral, headwater wild trout populations at a fine scale to serve as a planning and management tool for resource managers to maximize resistance and resilience of these populations in the face of anthropogenic stressors. We developed correlative logistic regression models to predict occurrence of brook trout, rainbow trout, and brown trout for every interconfluence stream reach in the study area. A stream network was generated to capture a more consistent representation of headwater streams. Each of the final models had four significant metrics in common: stream order, fragmentation, precipitation, and land cover. Strahler stream order was found to be the most influential variable in two of the three final models and the second most influential variable in the other model. Greater than 70% presence accuracy was achieved for all three models. The underrepresentation of headwater streams in commonly used hydrography datasets is an important consideration that warrants close examination when forecasting headwater species distributions and range estimates. Finally and additionally, it appears that a relative watershed position metric (e.g., stream order) is an important surrogate variable (even when elevation is included) for biotic interactions across the landscape in areas where headwater species distributions are influenced by topographical gradients.

  17. Predicting fine-scale distributions of peripheral aquatic species in headwater streams

    DOE PAGES

    DeRolph, Christopher R.; Nelson, Stacy A. C.; Kwak, Thomas J.; ...

    2014-12-09

    Headwater species and peripheral populations that occupy habitat at the edge of a species range may hold an increased conservation value to managers due to their potential to maximize intraspecies diversity and species' adaptive capabilities in the context of rapid environmental change. The southern Appalachian Mountains are the southern extent of the geographic range of native Salvelinus fontinalis and naturalized Oncorhynchus mykiss and Salmo trutta in eastern North America. In this paper, we predicted distributions of these peripheral, headwater wild trout populations at a fine scale to serve as a planning and management tool for resource managers to maximize resistancemore » and resilience of these populations in the face of anthropogenic stressors. We developed correlative logistic regression models to predict occurrence of brook trout, rainbow trout, and brown trout for every interconfluence stream reach in the study area. A stream network was generated to capture a more consistent representation of headwater streams. Each of the final models had four significant metrics in common: stream order, fragmentation, precipitation, and land cover. Strahler stream order was found to be the most influential variable in two of the three final models and the second most influential variable in the other model. Greater than 70% presence accuracy was achieved for all three models. The underrepresentation of headwater streams in commonly used hydrography datasets is an important consideration that warrants close examination when forecasting headwater species distributions and range estimates. Finally and additionally, it appears that a relative watershed position metric (e.g., stream order) is an important surrogate variable (even when elevation is included) for biotic interactions across the landscape in areas where headwater species distributions are influenced by topographical gradients.« less

  18. Predicting fine-scale distributions of peripheral aquatic species in headwater streams

    PubMed Central

    DeRolph, Christopher R; Nelson, Stacy A C; Kwak, Thomas J; Hain, Ernie F

    2015-01-01

    Headwater species and peripheral populations that occupy habitat at the edge of a species range may hold an increased conservation value to managers due to their potential to maximize intraspecies diversity and species' adaptive capabilities in the context of rapid environmental change. The southern Appalachian Mountains are the southern extent of the geographic range of native Salvelinus fontinalis and naturalized Oncorhynchus mykiss and Salmo trutta in eastern North America. We predicted distributions of these peripheral, headwater wild trout populations at a fine scale to serve as a planning and management tool for resource managers to maximize resistance and resilience of these populations in the face of anthropogenic stressors. We developed correlative logistic regression models to predict occurrence of brook trout, rainbow trout, and brown trout for every interconfluence stream reach in the study area. A stream network was generated to capture a more consistent representation of headwater streams. Each of the final models had four significant metrics in common: stream order, fragmentation, precipitation, and land cover. Strahler stream order was found to be the most influential variable in two of the three final models and the second most influential variable in the other model. Greater than 70% presence accuracy was achieved for all three models. The underrepresentation of headwater streams in commonly used hydrography datasets is an important consideration that warrants close examination when forecasting headwater species distributions and range estimates. Additionally, it appears that a relative watershed position metric (e.g., stream order) is an important surrogate variable (even when elevation is included) for biotic interactions across the landscape in areas where headwater species distributions are influenced by topographical gradients. PMID:25628872

  19. Estimating contributions of nitrate and herbicides from groundwater to headwater streams, northern Atlantic Coastal Plain, USA

    USGS Publications Warehouse

    Ator, Scott; Denver, Judith M.

    2012-01-01

    Groundwater transport often complicates understanding of surface-water contamination. We estimated the regional flux of nitrate and selected herbicides from groundwater to nontidal headwater streams of the Atlantic Coastal Plain (New Jersey through North Carolina) based on late-winter or spring base-flow samples from 174 streams. Sampled streams were selected randomly, and flux estimates are based on resulting population estimates rather than on empirical models, which have been used previously for similar estimates. Base-flow flux in the estimated 8,834 headwater streams of the study area are an estimated 21,200 kg/day of nitrate (as N) and 5.83, 0.565, and 20.7 kg/day of alachlor, atrazine, and metolachlor (and selected degradates), respectively. Base-flow flux of alachlor and metolachlor is <3% of the total base-flow flux of those compounds plus degradates. Base-flow flux of nitrate and herbicides as a percentage of applications is typically highest in well-drained areas and lowest in areas with abundant poor drainage and anoxic conditions. In Coastal Plain watersheds of Albemarle and Pamlico Sounds, <2% of applied nitrogen reaches headwater streams as base flow. On the Delmarva Peninsula part of the Chesapeake Bay watershed, however, more than 10% of such applications are transported through groundwater to streams, and base-flow nitrate flux represents 70% of total nitrogen flux in headwater streams.

  20. Decoupling of carbon dioxide and dissolved organic carbon in boreal headwater streams

    NASA Astrophysics Data System (ADS)

    Winterdahl, Mattias; Wallin, Marcus B.; Karlsen, Reinert Huseby; Laudon, Hjalmar; Öquist, Mats; Lyon, Steve W.

    2016-10-01

    Streams and rivers emit large quantities of carbon dioxide (CO2) to the atmosphere. The sources of this CO2 are in-stream mineralization of organic carbon (OC) and CO2 input via groundwater inflow, but their relative importance is largely unknown. In this study, we quantified the role of in-stream OC mineralization as a source of CO2 in a number of nested boreal headwater streams. The results showed that mineralization of stream OC contributed 3% of CO2 supersaturation at time scales comparable to the estimated water travel times in the streams (<24 h). Mass balances showed that downstream losses of OC were ≤3% in low-order streams, whereas up to 16% of the OC was lost in the largest (fourth order) streams. In contrast, 85% of the CO2 was lost along the stream network (longest total stream length = 17 km). Under the assumption that in-stream OC mineralization was the main source of stream CO2, higher rates of OC mineralization (6% of OC) than those reported across the literature (≤0.7% of OC) would be required to sustain observed CO2 supersaturation. Further, model results indicated that groundwater inflows were sufficient to sustain observed stream CO2 concentrations. We hence conclude that in-stream OC mineralization was a minor source of CO2 in these boreal headwater systems and that the main source of stream CO2 was inflowing groundwater transporting CO2 originating from soil respiration.

  1. The Estimated Likelihood of Nutrients and Pesticides in Nontidal Headwater Streams of the Maryland Coastal Plain During Base Flow

    EPA Science Inventory

    Water quality in nontidal headwater (first-order) streams of the Coastal Plain during base flow in the late winter and spring is related to land use, hydrogeology, and other natural or human influences in contributing watersheds. A random survey of 174 headwater streams of the Mi...

  2. Solute and sediment export from Amazon forest and soybean headwater streams.

    PubMed

    Riskin, Shelby H; Neill, Christopher; Jankowski, KathiJo; Krusche, Alex V; McHorney, Richard; Elsenbeer, Helmut; Macedo, Marcia N; Nunes, Darlisson; Porder, Stephen

    2017-01-01

    Intensive cropland agriculture commonly increases streamwater solute concentrations and export from small watersheds. In recent decades, the lowland tropics have become the world's largest and most important region of cropland expansion. Although the effects of intensive cropland agriculture on streamwater chemistry and watershed export have been widely studied in temperate regions, their effects in tropical regions are poorly understood. We sampled seven headwater streams draining watersheds in forest (n = 3) or soybeans (n = 4) to examine the effects of soybean cropping on stream solute concentrations and watershed export in a region of rapid soybean expansion in the Brazilian state of Mato Grosso. We measured stream flows and concentrations of NO3(-) , PO4(3-) , SO4(2-) , Cl(-) , NH4(+) , Ca(2+) , Mg(2+) , Na(+) , K(+) , Al(3+) , Fe(3+) , and dissolved organic carbon (DOC) biweekly to monthly to determine solute export. We also measured stormflows and stormflow solute concentrations in a subset of watersheds (two forest, two soybean) during two/three storms, and solutes and δ(18) O in groundwater, rainwater, and throughfall to characterize watershed flowpaths. Concentrations of all solutes except K(+) varied seasonally in streamwater, but only Fe(3+) concentrations differed between land uses. The highest streamwater and rainwater solute concentrations occurred during the peak season of wildfires in Mato Grosso, suggesting that regional changes in atmospheric composition and deposition influence seasonal stream solute concentrations. Despite no concentration differences between forest and soybean land uses, annual export of NH4(+) , PO4(3-) , Ca(2+) , Fe(3+) , Na(+) , SO4(2-) , DOC, and TSS were significantly higher from soybean than forest watersheds (5.6-fold mean increase). This increase largely reflected a 4.3-fold increase in water export from soybean watersheds. Despite this increase, total solute export per unit watershed area (i.e., yield) remained

  3. Large carbon dioxide fluxes from headwater boreal and sub-boreal streams.

    PubMed

    Venkiteswaran, Jason J; Schiff, Sherry L; Wallin, Marcus B

    2014-01-01

    Half of the world's forest is in boreal and sub-boreal ecozones, containing large carbon stores and fluxes. Carbon lost from headwater streams in these forests is underestimated. We apply a simple stable carbon isotope idea for quantifying the CO2 loss from these small streams; it is based only on in-stream samples and integrates over a significant distance upstream. We demonstrate that conventional methods of determining CO2 loss from streams necessarily underestimate the CO2 loss with results from two catchments. Dissolved carbon export from headwater catchments is similar to CO2 loss from stream surfaces. Most of the CO2 originating in high CO2 groundwaters has been lost before typical in-stream sampling occurs. In the Harp Lake catchment in Canada, headwater streams account for 10% of catchment net CO2 uptake. In the Krycklan catchment in Sweden, this more than doubles the CO2 loss from the catchment. Thus, even when corrected for aquatic CO2 loss measured by conventional methods, boreal and sub-boreal forest carbon budgets currently overestimate carbon sequestration on the landscape.

  4. FIELD OPERATIONS MANUAL FOR ASSESSING THE HYDROLOGIC PERMANENCE AND ECOLOGICAL CONDITION OF HEADWATER STREAMS

    EPA Science Inventory

    The purpose of this manual is to document procedures that were developed and used by the Ecological Exposure Research Division, NERL, ORD, for the assessment of the physical and biological characteristics of headwater streams; and to provide a catalog of procedures to other group...

  5. High frequency variability of environmental drivers determining benthic community dynamics in headwater streams.

    PubMed

    Snell, M A; Barker, P A; Surridge, B W J; Large, A R G; Jonczyk, J; Benskin, C McW H; Reaney, S; Perks, M T; Owen, G J; Cleasby, W; Deasy, C; Burke, S; Haygarth, P M

    2014-07-01

    Headwater streams are an important feature of the landscape, with their diversity in structure and associated ecological function providing a potential natural buffer against downstream nutrient export. Phytobenthic communities, dominated in many headwaters by diatoms, must respond to physical and chemical parameters that can vary in magnitude within hours, whereas the ecological regeneration times are much longer. How diatom communities develop in the fluctuating, dynamic environments characteristic of headwaters is poorly understood. Deployment of near-continuous monitoring technology in sub-catchments of the River Eden, NW England, provides the opportunity for measurement of temporal variability in stream discharge and nutrient resource supply to benthic communities, as represented by monthly diatom samples collected over two years. Our data suggest that the diatom communities and the derived Trophic Diatom Index, best reflect stream discharge conditions over the preceding 18-21 days and Total Phosphorus concentrations over a wider antecedent window of 7-21 days. This is one of the first quantitative assessments of long-term diatom community development in response to continuously-measured stream nutrient concentration and discharge fluctuations. The data reveal the sensitivity of these headwater communities to mean conditions prior to sampling, with flow as the dominant variable. With sufficient understanding of the role of antecedent conditions, these methods can be used to inform interpretation of monitoring data, including those collected under the European Water Framework Directive and related mitigation efforts.

  6. Investigation of Biogeochemical Functional Proxies in Headwater Streams Across a Range of Channel and Catchment Alterations

    NASA Astrophysics Data System (ADS)

    Berkowitz, Jacob F.; Summers, Elizabeth A.; Noble, Chris V.; White, John R.; DeLaune, Ronald D.

    2014-03-01

    Historically, headwater streams received limited protection and were subjected to extensive alteration from logging, farming, mining, and development activities. Despite these alterations, headwater streams provide essential ecological functions. This study examines proxy measures of biogeochemical function across a range of catchment alterations by tracking nutrient cycling (i.e., inputs, processing, and stream loading) with leaf litter fall, leaf litter decomposition, and water quality parameters. Nutrient input and processing remained highest in second growth forests (the least altered areas within the region), while recently altered locations transported higher loads of nutrients, sediments, and conductivity. Biogeochemical functional proxies of C and N input and processing significantly, positively correlated with rapid assessment results (Pearson coefficient = 0.67-0.81; P = 0.002-0.016). Additionally, stream loading equations demonstrate that N and P transport, sediment, and specific conductivity negatively correlated with rapid assessment scores (Pearson coefficient = 0.56-0.81; P = 0.002-0.048). The observed increase in stream loading with lower rapid assessment scores indicates that catchment alterations impact stream chemistry and that rapid assessments provide useful proxy measures of function in headwater ecosystems. Significant differences in nutrient processing, stream loading, water quality, and rapid assessment results were also observed between recently altered (e.g., mined) headwater streams and older forested catchments (Mann-Whitney U = 24; P = 0.01-0.024). Findings demonstrate that biogeochemical function is reduced in altered catchments, and rapid assessment scores respond to a combination of alteration type and recovery time. An analysis examining time and economic requirements of proxy measurements highlights the benefits of rapid assessment methods in evaluating biogeochemical functions.

  7. Similarities and Differences Between Headwater Streams in the Mountains and Piedmont of North Carolina

    NASA Astrophysics Data System (ADS)

    Eaton, L.

    2005-05-01

    Biological sampling has been underway in headwater streams in the North Carolina Piedmont for two years and in Mountain headwater streams for one. Streams in the mountains usually started at springs, whereas most piedmont streams are fed by surface water runoff. Watersheds above springs, both mountain and piedmont, were smaller (mean 4 acres) than surface water streams in both regions (mean 19 acres). While taxa richness at perennial mountain headwater sites was similar (mean 38 taxa/sample) to piedmont perennial sites (mean 35), macroinvertebrate abundance in the mountains (mean 540 organisms/sample) was nearly double the sample abundance in the piedmont (mean 295). In both ecoregions winter/spring peaks in taxa richness and abundance were observed. Intermittent segments in the mountains were rare, but occurred as wet weather springs, while in the piedmont, intermittent segments were stream channels above perennial reaches. In both types, taxa richness and abundance were very low when the channel was dry, but were only slightly below levels found in perennial segments when wet. There were few species confined to intermittent reaches. Most taxa collected in intermittent reaches were also found downstream in perennial reaches, however some groups (e.g. mayflies, caddisflies, odonates, megaloptera) were rarely found in intermittent segments.

  8. Hydrogeomorphic connectivity on roads crossing in rural headwaters and its effect on stream dynamics.

    PubMed

    Thomaz, Edivaldo L; Peretto, Gustavo T

    2016-04-15

    Unpaved roads are ubiquitous features that have been transforming the landscape through human history. Unpaved roads affect the water and sediment pathways through a catchment and impacts the aquatic ecosystem. In this study, we describe the effect of unpaved road on the hydrogeomorphic connectivity at the rural headwater scale. Measurement was based on the stream crossing approach, i.e., road superimposing the drainage system. We installed a Parshall flume coupled with single-stage suspended sediment sampler at each stream crossing. In addition, we displayed our monitoring scheme with an upscaling perspective from second-order to third-order stream. We concluded that the road-stream coupling dramatically changed the stream dynamic. The increase of discharge caused by roads at the headwater was 50% larger compared to unaffected streams. Additionally, suspended sediment concentration enhancement at stream crossings ranged from to 413% at second-order streams to 145% at third-order streams. The landform characteristics associated with the road network produced an important hydrogeomorphic disruption in the landscape. As a result, the sediment filter function of the riparian zone was reduced dramatically. Therefore, we recommend that projects for aquatic system restoration or conservation in rural landscape consider the role of the road network on stream dynamics.

  9. Hydrologic response of hillslope seeps and headwater streams of the Fort Worth Prairie

    NASA Astrophysics Data System (ADS)

    Slattery, Michael; Jones, Shannon

    2015-04-01

    There has been minimal research on the relationships among vegetation, topography, and hydrology of hillslope seeps and headwater streams in general, and in the Fort Worth Prairie ecoregion in particular. Unlike traditional descriptions of Midwestern tallgrass prairies, these riparian zones are often dominated by annuals. Due to the ephemeral or intermittent nature of headwater stream hydrology, the high variation of soil moisture restricts tallgrasses from dominating riparian zones. In this study we quantify the hydrologic regime of a Fort Worth Prairie hillslope hollow by analyzing the spatio-temporal response of soil moisture to precipitation and drying, its impact on runoff generation, and the vegetation-soil moisture relationship. We conducted the study between August 2012 to March 2013, under drought-like conditions that prevented streamflow. Results show that, despite extreme moisture stress, the hillslope seep completely saturates during wet periods and saturates along the hillslope base during dry conditions. Autumn vegetation most accurately aligns with moderate soil moisture conditions. This research describes Fort Worth Prairie headwater stream and seep habitats and provides a basis for how they function hydrologically to create a foundation for improved habitat management, protection, and restoration of riparian headwaters in North Central Texas.

  10. Spatially intensive sampling by electrofishing for assessing longitudinal discontinuities in fish distribution in a headwater stream

    USGS Publications Warehouse

    Le Pichon, Céline; Tales, Évelyne; Belliard, Jérôme; Torgersen, Christian E.

    2017-01-01

    Spatially intensive sampling by electrofishing is proposed as a method for quantifying spatial variation in fish assemblages at multiple scales along extensive stream sections in headwater catchments. We used this method to sample fish species at 10-m2 points spaced every 20 m throughout 5 km of a headwater stream in France. The spatially intensive sampling design provided information at a spatial resolution and extent that enabled exploration of spatial heterogeneity in fish assemblage structure and aquatic habitat at multiple scales with empirical variograms and wavelet analysis. These analyses were effective for detecting scales of periodicity, trends, and discontinuities in the distribution of species in relation to tributary junctions and obstacles to fish movement. This approach to sampling riverine fishes may be useful in fisheries research and management for evaluating stream fish responses to natural and altered habitats and for identifying sites for potential restoration.

  11. Headwater streams and forest management: does ecoregional context influence logging effects on benthic communities?

    USGS Publications Warehouse

    Medhurst, R. Bruce; Wipfli, Mark S.; Binckley, Chris; Polivka, Karl; Hessburg, Paul F.; Salter, R. Brion

    2010-01-01

    Effects of forest management on stream communities have been widely documented, but the role that climate plays in the disturbance outcomes is not understood. In order to determine whether the effect of disturbance from forest management on headwater stream communities varies by climate, we evaluated benthic macroinvertebrate communities in 24 headwater streams that differed in forest management (logged-roaded vs. unlogged-unroaded, hereafter logged and unlogged) within two ecological sub-regions (wet versus dry) within the eastern Cascade Range, Washington, USA. In both ecoregions, total macroinvertebrate density was highest at logged sites (P = 0.001) with gathering-collectors and shredders dominating. Total taxonomic richness and diversity did not differ between ecoregions or forest management types. Shredder densities were positively correlated with total deciduous and Sitka alder (Alnus sinuata) riparian cover. Further, differences in shredder density between logged and unlogged sites were greater in the wet ecoregion (logging × ecoregion interaction; P = 0.006) suggesting that differences in post-logging forest succession between ecoregions were responsible for differences in shredder abundance. Headwater stream benthic community structure was influenced by logging and regional differences in climate. Future development of ecoregional classification models at the subbasin scale, and use of functional metrics in addition to structural metrics, may allow for more accurate assessments of anthropogenic disturbances in mountainous regions where mosaics of localized differences in climate are common.

  12. BIODIVERSITY MANAGEMENT APPROACHES FOR STREAM-RIPARIAN AREAS: PERSPECTIVES FOR PACIFIC NORTHWEST HEADWATER FORESTS, MICROCLIMATES, AND AMPHIBIANS

    EPA Science Inventory

    Stream-riparian areas represent a nexus of biodiversity, with disproportionate numbers of species tied to and interacting within this key habitat. New research in Pacific Northwest headwater forests, especially the characterization of microclimates and amphibian distributions, is...

  13. Logging in western Oregon: responses of headwater habitats and stream amphibians

    USGS Publications Warehouse

    Corn, Paul Stephen; Bury, R. Bruce

    1989-01-01

    We compared occurrence and abundance of four species of aquatic amphibians in 23 streams flowing through uncut forests to 20 streams flowing through forests logged between 14 and 40 years prior to the study. Species richness was highest in streams in uncut forests. Eleven streams in uncut forests contained all four species, and only two of these streams had fewer than three species present. Eleven streams in logged stands had one or no species present, and only one contained all four species. Density and biomass of all four species were significantly greater (2–7 X) in streams in uncut forests. Physical comparisons between types of streams were similar, except that streams in logged stands had generally smaller substrata, resulting from increased sedimentation. Densities of Pacific giant salamanders (Dicamptodon ensatus) and Olympic salamanders (Rhyacotriton olymoicus) were positively correlated with stream gradient in logged stands, but not in uncut forests, suggesting that the disruptive effects of increased sedimentation are greatest in low-gradient streams. Tailed frogs (Ascaphus truei) and Dunn's salamanders (Plethodon dunni) occurred more often in streams in logged stands when uncut timber was present upstream, but neither density nor biomass of any species were related to either presence of uncut timber upstream or years since logging. Logging upstream from uncut forests also had no effect on the presence, density or biomass of any species. Tailed frogs and Olympic salamanders may be extirpated from headwaters traversing clearcuts; these streams should be afforded some protection in plans for managed forests.

  14. Nitrate sinks and sources as controls of spatio-temporal water quality dynamics in an agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Schuetz, Tobias; Gascuel-Odoux, Chantal; Durand, Patrick; Weiler, Markus

    2016-02-01

    Several controls are known to affect water quality of stream networks during flow recession periods, such as solute leaching processes, surface water-groundwater interactions as well as biogeochemical in-stream turnover processes. Throughout the stream network, combinations of specific water and solute export rates and local in-stream conditions overlay the biogeochemical signals from upstream sections. Therefore, upstream sections can be considered functional units which could be distinguished and ordered regarding their relative contribution to nutrient dynamics at the catchment outlet. Based on snapshot sampling of flow and nitrate concentrations along the stream in an agricultural headwater during the summer flow recession period, we determined spatial and temporal patterns of water quality for the whole stream. A data-driven, in-stream-mixing-and-removal model was developed and applied for analysing the spatio-temporal in-stream retention processes and their effect on the spatio-temporal fluxes of nitrate from subcatchments. Thereby, we have been able to distinguish quantitatively between nitrate sinks, sources per stream reaches, and subcatchments, and thus we could disentangle the overlay of nitrate sink and source signals. For nitrate sources, we determined their permanent and temporal impact on stream water quality and for nitrate sinks, we found increasing nitrate removal efficiencies from upstream to downstream. Our results highlight the importance of distinct nitrate source locations within the watershed for in-stream concentrations and in-stream removal processes, respectively. Thus, our findings contribute to the development of a more dynamic perception of water quality in streams and rivers concerning ecological and sustainable water resource management.

  15. Reach-scale geomorphic differences between headwater streams draining mountaintop mined and unmined catchments

    NASA Astrophysics Data System (ADS)

    Jaeger, Kristin L.

    2015-05-01

    Mountaintop surface mining (MTM) is a controversial coal extraction method commonly practiced in the central and southern Appalachian Mountains, USA, that drastically reengineers previously steep, forested landscapes and alters sediment and water delivery processes to and along headwater channels draining mined areas. Although sediment delivery and hydrologic response from MTM operations remain highly variable and poorly resolved, the inherent close coupling between hillslopes and headwater channels is expected to result in geomorphic differences in stream channels draining MTM landscapes relative to unmined landscapes. Dedicated geomorphic studies are severely lacking in comparison to extensive research on water quality impacts of MTM. This study reports moderate geomorphic differences between headwater (catchment area <~ 6 km2) stream channels draining MTM and unmined catchments in tributaries of the Mud River in southern West Virginia. Univariate and multivariate analyses indicate that MTM streams are characterized by deeper maximum channel depths, smaller width-to-depth ratios, increased bedrock exposure along the streambed, and increased frequency of very fine silt and sand deposition relative to channels draining unmined catchments. Geomorphic differences are most pronounced for streams draining the smallest catchment areas (< 3.5 km2). Collectively, geomorphic differences provide evidence for relatively rapid channel adjustment of accelerated bedrock incision attributed to potential increased hydraulic driving forces and altered sediment regimes in MTM channels, notably sustained delivery of very fine sediment and potentially reduced coarse sediment delivery. More rapid delivery and transfer of water in addition to excess delivery of very fine sediments to and through headwater channels will have consequences to flooding and water quality in the short term and landscape evolution processes over longer time scales. Given the extent of MTM operations in this

  16. Effect of riparian vegetation on diatom assemblages in headwater streams under different land uses.

    PubMed

    Hlúbiková, Daša; Novais, Maria Helena; Dohet, Alain; Hoffmann, Lucien; Ector, Luc

    2014-03-15

    Differences in the structure of diatom assemblages in headwaters with contrasting shading conditions and different land use in the buffer zone and upper catchment were studied in order to evaluate the influence of the lack of riparian vegetation on the biofilm. The objective was to ascertain whether a riparian buffer can mitigate the negative influence of human induced disturbance and pollution on diatom assemblages in headwaters. Four streams were selected in order to maximize the differences in the land cover and minimize other environmental gradients. Multivariate statistics, different comparative and permutation tests and correlations were applied to compare the diatom assemblages, the Specific Polluosensitivity Index (IPS) and the diatom ecological guilds (low profile, high profile and motile) among the sites studied and to evaluate their responses to disturbances. The analysis showed that low profile diatoms typically dominated in forested headwaters with limited resources, whilst assemblages at impacted sites showed a wider range of growth forms. In unimpacted streams, the diatom assemblages were influenced by temperature, pH, conductivity and calcium, as usually reported for oligotrophic streams with high natural disturbance due to fast current and shading. In both shaded and unshaded impacted streams, the importance of nutrients and land use disturbance, especially urbanization, prevailed. This trend was also reflected by the IPS index that showed consistently lower values at impacted sites, correlating most significantly with nutrients. The diatom species composition as well as diatom guilds at impacted sites were similar, regardless of the presence or absence of riparian vegetation, and were significantly influenced by seasonal changes. Our results indicate that diatoms react sensitively to alterations of the water environment in headwaters, induced by anthropogenic activities, and these impacts are not buffered by an intact riparian zone. Diatoms

  17. Riparian communities associated with Pacific Northwest headwater streams: assemblages, processes, and uniqueness

    USGS Publications Warehouse

    Richardson, J.S.; Naiman, R.J.; Swanson, F.J.; Hibbs, D.E.

    2005-01-01

    Riparian areas of large streams provide important habitat to many species and control many instream processes a?? but is the same true for the margins of small streams? This review considers riparian areas alongside small streams in forested, mountainous areas of the Pacific Northwest and asks if there are fundamental ecological differences from larger streams and from other regions and if there are consequences for management from any differences. In the moist forests along many small streams of the Pacific Northwest, the contrast between the streamside and upslope forest is not as strong as that found in drier regions. Small streams typically lack floodplains, and the riparian area is often constrained by the hillslope. Nevertheless, riparian-associated organisms, some unique to headwater areas, are found along small streams. Disturbance of hillslopes and stream channels and microclimatic effects of streams on the riparian area provide great heterogeneity in processes and diversity of habitats. The tight coupling of the terrestrial riparian area with the aquatic system results from the closed canopy and high edge-to-area ratio for small streams. Riparian areas of the temperate, conifer dominated forests of the Pacific Northwest provide a unique environment. Forest management guidelines for small streams vary widely, and there has been little evaluation of the local or downstream consequences of forest practices along small streams.

  18. A hydrologic connectivity index for jurisdictional analysis of headwater streams in a montane watershed.

    PubMed

    Caruso, Brian S

    2015-10-01

    A hydrologic connectivity index (HCI) was developed to aid the US Clean Water Act Section 404 jurisdictional evaluation of headwater streams in montane watersheds, using the Cement Creek Watershed in the San Juan Mountains, Colorado as a case study. Jurisdictional determinations are required for many intermittent and ephemeral streams, where significant nexus with downstream traditional navigable waters (TNWs) must be evaluated. Three biophysical metrics (a streamflow metric, distance from the stream to the TNW, and slope between the stream and the TNW) for 239 streams in the watershed were used to develop three indices. These were then combined to develop the HCI, which is a compound, additive index. There was a large range of HCI values for ephemeral streams, which all require a significant nexus evaluation to determine jurisdiction. Statistical analysis of HCI values across stream duration and order classes showed that mean values differed significantly among classes. The flow index component constituted the greatest proportion of the HCI for perennial streams, was sensitive to the flow metrics used, and was greatest for high flows. Although ephemeral streams are only connected to the TNW less than 3 months of the year, the cumulative average annual flow contribution of ephemeral first-order streams can be 5% of the total to the TNW, and their flow contribution is larger during high flows. Some ephemeral streams with high HCI values are farthest from the TNW but contribute the greatest flow out of all ephemeral reaches, and may have significant nexus with the river. The study shows that the HCI can be useful for initial evaluation of connectivity, significant nexus, and jurisdiction of headwaters at the watershed scale.

  19. A Spatially Explicit Approach for Evaluating Relationships among Coastal Cutthroat, Habitat, and Disturbance in Headwater Streams

    NASA Astrophysics Data System (ADS)

    Gresswell, R. E.; Bateman, D. S.; Torgersen, C. E.; Guy, T. J.; Hendricks, S. R.; Wofford, J. E.

    2005-05-01

    Headwater stream systems are complex networks that form a physicochemical template governing the persistence of aquatic species such as coastal cutthroat trout. Individual portions of the network can function as conduits or receptacles for sediments, wood, and nutrients from terrestrial areas. Temporal and spatial changes in the delivery of these constituents can substantially alter the habitat template and its ability to support this native fish. Our study of 40 mid-sized watersheds (500 - 1,500 ha) in western Oregon is providing new insights into the factors affecting the distribution of coastal cutthroat trout within, and among, headwater stream networks. For example, data suggest that coastal cutthroat trout move throughout the accessible portions of headwater streams for reproductive, feeding, and refuge purposes. Fish congregate in these areas and form local populations that may exhibit unique phenotypic and genetic attributes. At times, coastal cutthroat trout move into larger downstream portions of the network where they may contribute to the persistence and genetic character of anadromous or local potamodromous assemblages. Variation in distribution patterns among watersheds reflects diverse environments and selective factors, such as geology, geomorphology, climate, and land-management history. Our research findings suggest that human activities that impede movement among suitable habitat patches can have lasting consequences for local assemblages of coastal cutthroat trout and may ultimately affect persistence.

  20. Low prevalence of chytrid fungus (Batrachochytrium dendrobatidis) in amphibians of U.S. headwater streams

    USGS Publications Warehouse

    Hossack, Blake R.; Adams, Michael J.; Campbell Grant, Evan H.; Pearl, Chistopher A.; Bettaso, James B.; Barichivich, William J.; Lowe, Winsor H.; True, Kimberly; Ware, Joy L.; Corn, Paul Stephen

    2010-01-01

    Many declines of amphibian populations have been associated with chytridiomycosis, a disease caused by the aquatic fungus Batrachochytrium dendrobatidis (Bd). Despite the relatively high prevalence of chytridiomycosis in stream amphibians globally, most surveys in North America have focused primarily on wetland-associated species, which are frequently infected. To better understand the distribution and prevalence of Bd in headwater amphibian communities, we sampled 452 tailed frogs (Ascaphus truei and Ascaphus montanus) and 304 stream salamanders (seven species in the Dicamptodontidae and Plethodontidae) for Bd in 38, first- to third-order streams in five montane areas across the United States. We tested for presence of Bd by using PCR on skin swabs from salamanders and metamorphosed tailed frogs or the oral disc of frog larvae. We detected Bd on only seven individuals (0.93%) in four streams. Based on our study and results from five other studies that have sampled headwater- or seep-associated amphibians in the United States, Bd has been detected on only 3% of 1,322 individuals from 21 species. These results differ strongly from surveys in Central America and Australia, where Bd is more prevalent on stream-breeding species, as well as results from wetland-associated anurans in the same regions of the United States that we sampled. Differences in the prevalence of Bd between stream- and wetland-associated amphibians in the United States may be related to species-specific variation in susceptibility to chytridiomycosis or habitat differences.

  1. Spatial and temporal water quality dynamics during baseflow in an agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Schuetz, Tobias; Weiler, Markus; Saroos, Manuel

    2013-04-01

    Understanding the interaction of time variant source areas and biogeochemical in-stream processes and the determination of resulting spatial and temporal signatures of stream water composition will improve the prediction and management of water quality at the catchment scale. During baseflow periods runoff source areas can change over time depending e.g. on storage depletion rates, actual wetness, groundwater level or local evapotranspiration rates. Due to the resulting space/time variant water fluxes, these effects are also expressed in the physico-chemical composition of surface waters. Unfortunately the resulting signature is often overlain by biogeochemical in-stream processes, which make it difficult to identify physico-chemical signatures of specific runoff source areas. We studied these interactions in a 1.7 km² agricultural headwater catchment. A dense artificial drainage network and a predominantly impervious streambed allowed for detecting distinct locations of groundwater inflow and determining ongoing biogeochemical in-stream processes. The analysis of sub-catchment storage depletion and resulting time variant quantitative and qualitative impacts on stream water composition was based on observations made during 11 catchment wide synoptic sampling campaigns during the summer baseflow period. We measured stream discharges with salt dilution gauging as well as water temperatures (T) and electrical conductivity (EC) upstream, downstream and inside all active drain pipes. During two campaigns we took additional water samples for major ion analysis at all sampling points. Discharges, T and EC stream-network data sets were used to spatially determine groundwater contributions using mixing equations for 2 and 3 components, respectively. Thereby we derived local baseflow recessions in relation to the catchment wide stream discharge. Using a water balance approach we determined active runoff source areas for each drain pipe and identified the dominant land use

  2. Do the coarsest bed fractions and stream power record contemporary trends in steep headwater channels?

    NASA Astrophysics Data System (ADS)

    Galia, Tomáš; Škarpich, Václav

    2016-11-01

    Three stream channels that were devoid of evidence of past debris flows and one headwater channel that contained debris flow deposits in the flysch western Carpathians, Czech Republic were selected to test relationships between in-channel processes, bed sediments, and unit stream power calculated for bankfull and Q20 flows. Contemporary depositional or erosional trends in the examined headwaters were linked with bed sediments that were represented by the coarsest cobble and boulder fraction with a mean calculated from the five largest particles. The downstream trends of the unit stream power were derived for a bankfull discharge and a well-documented 20-year flood event. In addition, the flow competences during the discharges were calculated using indirect bedload transport measurements. Downstream fining of the cobble and boulder fraction was observed in all of the studied headwaters, and unique downstream variations of the unit stream power were calculated for the longitudinal profiles. The single-thread streams that were devoid of evidence of debris flow events exhibited direct relations between the coarsest sediment size and the unit stream power, especially as calculated for the 20-year flood event and for erosional/depositional trends of the channel. The downstream coarsening of the bed material that was accompanied by an increase in the unit stream power was usually observed in the case of deeply incised (> 0.5 m above the assumed bankfull depth) channel reaches. The calculated competence of the 20-year flow was up to twofold higher than that required to entrain the largest bed particle diameters in those channel reaches, and even the bankfull flow was potentially capable of transporting the coarsest bed particles in certain of the reaches. On the other hand, some depositional channel reaches evidently led to the disconnectivity of transport of the coarsest bed material even in the case of the 20-year flood event. The longitudinal profile of the channel that

  3. Groundtruthing and potential for predicting acid deposition impacts in headwater streams using bedrock geology, GIS, angling, and stream chemistry.

    PubMed

    Kirby, C S; McInerney, B; Turner, M D

    2008-04-15

    Atmospheric acid deposition is of environmental concern worldwide, and the determination of impacts in remote areas can be problematic. Rainwater in central Pennsylvania, USA, has a mean pH of approximately 4.4. Bedrock varies dramatically in its ability to neutralize acidity. A GIS database simplified reconnaissance of non-carbonate bedrock streams in the Valley and Ridge Province and identified potentially chronically impacted headwater streams, which were sampled for chemistry and brook trout. Stream sites (n=26) that originate in and flow through the Tuscarora had a median pH of 5.0 that was significantly different from other formations. Shawangunk streams (n=6) and non-Tuscarora streams (n=20) had a median pH of 6.0 and 6.3, respectively. Mean alkalinity for non-Tuscarora streams (2.6 mg/L CaCO(3)) was higher than the mean for Tuscarora streams (0.5 mg/L). Lower pH and alkalinity suggest that the buffering capability of the Tuscarora is inferior to that of adjacent sandstones. Dissolved aluminum concentrations were much higher for Tuscarora streams (0.2 mg/L; approximately the lethal limit for brook trout) than for non-Tuscarora streams (0.03 mg/L) or Shawangunk streams (0.02 mg/L). Hook-and-line methods determined the presence/absence of brook trout in 47 stream reaches with suitable habitat. Brook trout were observed in 21 of 22 non-Tuscarora streams, all 6 Shawangunk streams, and only 9 of 28 Tuscarora stream sites. Carefully-designed hook-and-line sampling can determine the presence or absence of brook trout and help confirm biological impacts of acid deposition. 15% of 334 km of Tuscarora stream lengths are listed as "impaired" due to atmospheric deposition by the Pennsylvania Department of Environmental Protection. 65% of the 101 km of Tuscarora stream lengths examined in this study were impaired.

  4. Real exposure: field measurement of chemical plumes in headwater streams.

    PubMed

    Edwards, David D; Moore, Paul A

    2014-10-01

    In fluvial systems, organismic exposure to nonpoint source pollutants will fluctuate in frequency (exposure events), intensity (concentration), and duration. The reliance on lethal concentrations and static exposure in many laboratory studies does not adequately represent nor address exposure to in situ chemical plumes of fluvial habitats. To adequately address field exposure in a laboratory setting, one needs an understanding of the physics of chemical transmission within moving fluids. Because of the chaotic nature of turbulence, chemical plumes introduced to fluvial systems have a spatial and temporal microstructure with fluxes in chemical concentration. Consequently, time-averaged static exposure models are not ecologically relevant for the major reason of in situ distribution. The purpose of this study was to quantify in situ chemical distribution and dispersion within two physically different streams. Dopamine was introduced as a chemical tracer mimicking groundwater runoff. Chemical fluxes and stream hydrodynamics were simultaneously measured using a microelectrode and an acoustic Doppler velocimeter, respectively, at three heights of three downstream locations at each research site. Fine-scale measurements of the dopamine plume microstructure showed that organisms could be exposed to chemical fluctuations where concentrations are significantly greater than the overall time-averaged concentration. These measurements demonstrate that rather than relying on static exposure, standards for pollution must consider the concept of exposure being interdependently linked to flow of the fluid medium. The relationship between fluid dynamics, pollution exposure, and organism physiology are complex and must be evaluated in ways to mimic natural systems.

  5. Real exposure: Field measurement of chemical plumes in headwater streams

    NASA Astrophysics Data System (ADS)

    Edwards, David D.

    In fluvial systems, organismic exposure to nonpoint source pollutants will fluctuate in frequency (exposure events), intensity (concentration), and duration. The reliance on lethal concentrations and static exposure in many laboratory studies does not adequately represent nor address exposure to in situ chemical plumes of fluvial habitats. In order to adequately address field exposure in a lab setting, one needs an understanding of the physics of chemical transmission within moving fluids. Because of the chaotic nature of turbulence, chemical plumes introduced to fluvial systems have a spatial and temporal microstructure with fluxes in chemical concentration. Consequently, time-averaged static exposure models are not ecologically relevant for the major reason of in situ distribution. The purpose of this study was to quantify in situ chemical distribution and dispersion within two physically different streams. Dopamine was introduced as a chemical tracer mimicking groundwater runoff. Chemical fluxes and stream hydrodynamics were simultaneously measured using a microelectrode and an acoustic doppler velocimeter (ADV), respectively, at three heights of three downstream locations at each research site. Fine-scale measurements of the dopamine plume microstructure showed organisms could be exposed to chemical fluctuations where concentrations are significantly greater than the overall time-averaged concentration. These measurements demonstrate that rather than relying on static exposure, standards for pollution need to consider the concept of exposure being interdependently linked to flow of the fluid medium. The relationship between fluid dynamics, pollution exposure and organism physiology are complex and need to be evaluated in ways to mimic natural systems.

  6. Spatial and temporal patterns of stream burial and its effect on habitat connectivity across headwater stream communities of the Potomac River Basin, USA

    NASA Astrophysics Data System (ADS)

    Weitzell, R.; Guinn, S. M.; Elmore, A. J.

    2012-12-01

    The process of directing streams into culverts, pipes, or concrete-lined ditches during urbanization, known as stream burial, alters the primary physical, chemical, and biological processes of streams. Knowledge of the cumulative impacts of reduced structure and ecological function within buried stream networks is crucial for informing management of stream ecosystems, in light of continued growth in urban areas, and the uncertain response of freshwater ecosystems to the stresses of global climate change. To address this need, we utilized recently improved stream maps for the Potomac River Basin (PRB) to describe the extent and severity of stream burial across the basin. Observations of stream burial made from high resolution aerial photographs (>1% of total basin area) and a decision tree using spatial statistics from impervious cover data were used to predict stream burial at 4 time-steps (1975, 1990, 2001, 2006). Of the roughly 95,500 kilometers (km) of stream in the PRB, approximately 4551 km (4.76%) were buried by urban development as of 2001. Analysis of county-level burial trends shows differential patterns in the timing and rates of headwater stream burial, which may be due to local development policies, topographical constraints, and/or time since development. Consistently higher rates of stream burial were observed for small streams, decreasing with stream order. Headwater streams (1st-2nd order) are disproportionately affected, with burial rates continuing to increase over time in relation to larger stream orders. Beyond simple habitat loss, headwater burial decreases connectivity among headwater populations and habitats, with potential to affect a wide range of important ecological processes. To quantify changes to regional headwater connectivity we applied a connectivity model based on electrical circuit theory. Circuit-theoretical models function by treating the landscape as a resistance surface, representing hypothesized relationships between

  7. Interaction of esker groundwater with headwater lakes and streams

    NASA Astrophysics Data System (ADS)

    Ala-aho, Pertti; Rossi, Pekka M.; Kløve, Bjørn

    2013-09-01

    Groundwater-surface water interactions were studied in a Finnish esker aquifer system where some lakes suffer from periodic water level decline and others from eutrophication. Natural tracers (Ca2+, SiO2 and PO43-) were used on the aquifer scale and seepage meter measurements and water level recordings on the single lake scale to better understand the complex interactions between groundwater, lakes and streams in the area. The natural tracers showed that lakes located in lower landscape positions and connected with streams were richer in tracer concentrations and that their water chemistry resembled that of the groundwater. On the other hand, closed basin lakes located at higher altitudes were nutrient-poor seepage lakes with some groundwater through flow. The data suggests that the subsurface acts as a phosphate source for the surface water bodies and the nutrient rich groundwater inseepage dictates the trophic status of the lakes in the area. The seepage meter measurements verified a strong interaction between groundwater and surface water and revealed spatial distribution of lake seepage and a temporal co-variation in lake seepage rates. A statistical analysis of seepage meter and water level observation time series were useful to show groundwater flow regimes controlling lake seepage. Using the natural tracer analysis and seepage meter measurements, we developed a novel conceptual model for the study site where the differences in lake trophic state and water table behavior were explained by assigning lakes to local and regional groundwater flow regimes. The obtained results provide new knowledge on using natural tracers in complex glacial aquifer systems and can be used in integrated groundwater-surface water management.

  8. Instream wood recruitment, channel complexity, and their relationship to stream ecology in forested headwater streams under alternative stable states

    NASA Astrophysics Data System (ADS)

    Livers, B.; Wohl, E.

    2015-12-01

    Human alteration to forests has had lasting effects on stream channels worldwide. Such land use changes affect how wood enters and is stored in streams as individual pieces and as logjams. Changes in wood recruitment affect the complexity and benefits wood can provide to the stream environment, such as zones of flow separation that store fine sediment and organic matter, increased nutrient processing, and greater habitat potential, which can enhance biota and cascade through stream-riparian ecosystems. Previous research in our study area shows that modern headwater streams flowing through old-growth, unmanaged forests have more wood than streams in young, managed forests, but does not explicitly evaluate how wood affects channel complexity or local ecology. 'Managed' refers to forests previously or currently exposed to human alteration. Alteration has long since ceased in some areas, but reduced wood loads in managed streams persist. Our primary objective was to quantify stream complexity metrics, with instream wood as a mediator, on streams across a gradient of management and disturbance histories in order to examine legacy effects of human alteration to forests. Data collected in the Southern Rocky Mountains include 24 2nd to 3rd order subalpine streams categorized into: old-growth unmanaged; younger, naturally disturbed unmanaged; and younger managed. We assessed instream wood loads and logjams and evaluated how they relate to channel complexity using a number of metrics, such as standard deviation of bed and banks, volume of pools, ratios of stream to valley lengths and stream to valley area, and diversity of substrate, gradient, and morphology. Preliminary results show that channel complexity is directly related to instream wood loads and is greatest in streams in old-growth. Related research in the field area indicates that streams with greater wood loads also have increased nutrient processing and greater abundance and diversity of aquatic insect predators.

  9. Influence of eastern hemlock (Tsuga canadensis) forests on aquatic invertebrate assemblages in headwater streams

    USGS Publications Warehouse

    Snyder, C.D.; Young, J.A.; Lemarie, D.P.; Smith, D.R.

    2002-01-01

    We conducted a comparative study in the Delaware Water Gap National Recreation Area to determine the potential long-term impacts of hemlock forest decline on stream benthic macroinvertebrate assemblages. Hemlock forests throughout eastern North America have been declining because of the hemlock woolly adelgid, an exotic insect pest. We found aquatic invertebrate community structure to be strongly correlated with forest composition. Streams draining hemlock forests supported significantly more total taxa than streams draining mixed hardwood forests, and over 8% of the taxa were strongly associated with hemlock. In addition, invertebrate taxa were more evenly distributed (i.e., higher Simpson's evenness values) in hemlock-drained streams. In contrast, the number of rare species and total densities were significantly lower in streams draining hemlock, suggesting that diversity differences observed between forest types were not related to stochastic factors associated with sampling and that streams draining mixed hardwood forests may be more productive. Analysis of stream habitat data indicated that streams draining hemlock forests had more stable thermal and hydrologic regimes. Our findings suggest that hemlock decline may result in long-term changes in headwater ecosystems leading to reductions in both within-stream (i.e., alpha) and park-wide (i.e., gamma) benthic community diversity.

  10. Microbial responses to changes in flow status in temporary headwater streams: a cross-system comparison

    PubMed Central

    Febria, Catherine M.; Hosen, Jacob D.; Crump, Byron C.; Palmer, Margaret A.; Williams, D. Dudley

    2015-01-01

    Microbial communities are responsible for the bulk of biogeochemical processing in temporary headwater streams, yet there is still relatively little known about how community structure and function respond to periodic drying. Moreover, the ability to sample temporary habitats can be a logistical challenge due to the limited capability to measure and predict the timing, intensity and frequency of wet-dry events. Unsurprisingly, published datasets on microbial community structure and function are limited in scope and temporal resolution and vary widely in the molecular methods applied. We compared environmental and microbial community datasets for permanent and temporary tributaries of two different North American headwater stream systems: Speed River (Ontario, Canada) and Parkers Creek (Maryland, USA). We explored whether taxonomic diversity and community composition were altered as a result of flow permanence and compared community composition amongst streams using different 16S microbial community methods (i.e., T-RFLP and Illumina MiSeq). Contrary to our hypotheses, and irrespective of method, community composition did not respond strongly to drying. In both systems, community composition was related to site rather than drying condition. Additional network analysis on the Parkers Creek dataset indicated a shift in the central microbial relationships between temporary and permanent streams. In the permanent stream at Parkers Creek, associations of methanotrophic taxa were most dominant, whereas associations with taxa from the order Nitrospirales were more dominant in the temporary stream, particularly during dry conditions. We compared these results with existing published studies from around the world and found a wide range in community responses to drying. We conclude by proposing three hypotheses that may address contradictory results and, when tested across systems, may expand understanding of the responses of microbial communities in temporary streams to

  11. Elevated aluminium concentration in acidified headwater streams lowers aquatic hyphomycete diversity and impairs leaf-litter breakdown.

    PubMed

    Baudoin, J M; Guérold, F; Felten, V; Chauvet, E; Wagner, P; Rousselle, P

    2008-08-01

    Aquatic hyphomycetes play an essential role in the decomposition of allochthonous organic matter which is a fundamental process driving the functioning of forested headwater streams. We studied the effect of anthropogenic acidification on aquatic hyphomycetes associated with decaying leaves of Fagus sylvatica in six forested headwater streams (pH range, 4.3-7.1). Non-metric multidimensional scaling revealed marked differences in aquatic hyphomycete assemblages between acidified and reference streams. We found strong relationships between aquatic hyphomycete richness and mean Al concentration (r = -0.998, p < 0.0001) and mean pH (r = 0.962, p < 0.002), meaning that fungal diversity was severely depleted in acidified streams. By contrast, mean fungal biomass was not related to acidity. Leaf breakdown rate was drastically reduced under acidic conditions raising the issue of whether the functioning of headwater ecosystems could be impaired by a loss of aquatic hyphomycete species.

  12. Distribution of Amphipods (Gammarus nipponensis Ueno) Among Mountain Headwater Streams with Different Legacies of Debris Flow Occurrence

    EPA Science Inventory

    To understand the impacts of debris flows on the distribution of an amphipod with limited dispersal ability in the context of stream networks, we surveyed the presence of Gammarus nipponensis in 87 headwater streams with different legacies of debris flow occurrence within an 8.5-...

  13. Ontogenetic and diel variation in stream habitat use by brook trout (Salvelinus fontinalis) in a headwater stream

    USGS Publications Warehouse

    Johnson, J.H.; Ross, R.M.; Dropkin, D.S.; Redell, L.A.

    2011-01-01

    Although considerable information exists on habitat use by stream salmonids, only a small portion has quantitatively examined diurnal and nocturnal habitat variation. We examined diel variation in habitat use by age-0 and age-1+ brook trout (Salvelinus fontinalis) during summer and autumn in a headwater stream in northern Pennsylvania. Habitat variables measured included cover, depth, substrate, and velocity. The most pronounced diel variation occurred in the use of cover during both seasons. Both age-0 brook trout and age-1+ trout were associated with less cover at night. Age-0 brook trout occupied swifter water during the day than at night during both seasons, but the difference was not significant. Increased cover, depth, and substrate size governed the habitat of age-1+ brook trout. Our findings support the need for a better understanding of diel differences in habitat use of stream salmonids when considering habitat enhancement and protection.

  14. Emissions of carbon dioxide and methane from a headwater stream network of interior Alaska

    USGS Publications Warehouse

    Crawford, John T.; Striegl, Robert G.; Wickland, Kimberly P.; Dornblaser, Mark M.; Stanley, Emily H.

    2013-01-01

    Boreal ecosystems store significant quantities of organic carbon (C) that may be vulnerable to degradation as a result of a warming climate. Despite their limited coverage on the landscape, streams play a significant role in the processing, gaseous emission, and downstream export of C, and small streams are thought to be particularly important because of their close connection with the surrounding landscape. However, ecosystem carbon studies do not commonly incorporate the role of the aquatic conduit. We measured carbon dioxide (CO2) and methane (CH4) concentrations and emissions in a headwater stream network of interior Alaska underlain by permafrost to assess the potential role of stream gas emissions in the regional carbon balance. First-order streams exhibited the greatest variability in fluxes of CO2 and CH4,and the greatest mean pCO2. High-resolution time series of stream pCO2 and discharge at two locations on one first-order stream showed opposing pCO2 responses to storm events, indicating the importance of hydrologic flowpaths connecting CO2-rich soils with surface waters. Repeated longitudinal surveys on the stream showed consistent areas of elevated pCO2 and pCH4, indicative of discrete hydrologic flowpaths delivering soil water and groundwater having varying chemistry. Up-scaled basin estimates of stream gas emissions suggest that streams may contribute significantly to catchment-wide CH4 emissions. Overall, our results indicate that while stream-specific gas emission rates are disproportionately high relative to the terrestrial landscape, both stream surface area and catchment normalized emission rates were lower than those documented for the Yukon River Basin as a whole. This may be due to limitations of C sources and/or C transport to surface waters.

  15. Quantifying spatial scaling patterns and their local and regional correlates in headwater streams: Implications for resilience

    USGS Publications Warehouse

    Gothe, Emma; Sandin, Leonard; Allen, Craig R.; Angeler, David G.

    2014-01-01

    The distribution of functional traits within and across spatiotemporal scales has been used to quantify and infer the relative resilience across ecosystems. We use explicit spatial modeling to evaluate within- and cross-scale redundancy in headwater streams, an ecosystem type with a hierarchical and dendritic network structure. We assessed the cross-scale distribution of functional feeding groups of benthic invertebrates in Swedish headwater streams during two seasons. We evaluated functional metrics, i.e., Shannon diversity, richness, and evenness, and the degree of redundancy within and across modeled spatial scales for individual feeding groups. We also estimated the correlates of environmental versus spatial factors of both functional composition and the taxonomic composition of functional groups for each spatial scale identified. Measures of functional diversity and within-scale redundancy of functions were similar during both seasons, but both within- and cross-scale redundancy were low. This apparent low redundancy was partly attributable to a few dominant taxa explaining the spatial models. However, rare taxa with stochastic spatial distributions might provide additional information and should therefore be considered explicitly for complementing future resilience assessments. Otherwise, resilience may be underestimated. Finally, both environmental and spatial factors correlated with the scale-specific functional and taxonomic composition. This finding suggests that resilience in stream networks emerges as a function of not only local conditions but also regional factors such as habitat connectivity and invertebrate dispersal.

  16. Landscape Pattern, Network Structure, and the Distribution of Coastal Cutthroat Trout in Headwater Streams

    NASA Astrophysics Data System (ADS)

    Torgersen, C. E.; Gresswell, R. E.; Bateman, D. S.; Hockman-Wert, D. P.

    2005-05-01

    Headwater streams are dynamic environments in which landscape characteristics exert strong influences on the distribution of stream fishes. Although geology, topographic factors, and land use have been shown to affect trout population density at a site-specific level, few studies have investigated landscape features associated with the spatial extent and scale of variation of trout distribution in an entire watershed. To evaluate landscape influences on the distribution and abundance of coastal cutthroat trout (Oncorhynchus clarki clarki), we conducted spatially continuous surveys of stream habitat and trout abundance in forty randomly selected watersheds (500-1000 ha) in the Cascades, Coast Range, and Klamath Mountains ecoregions of western Oregon. Our investigation of coastal cutthroat trout populations across a broad range of headwater environments revealed that landscape features, including topography, geology, network structure, annual precipitation, and stand replacement disturbance, were associated with the spatial extent and scale of variation of trout distribution within watersheds. Understanding effects of basin-scale factors on trout distribution and abundance is critical in forested regions such as the Pacific Northwest where resource managers must consider potential impacts of logging on aquatic ecosystems.

  17. Feeding and reproductive patterns of Astyanax intermedius in a headwater stream of Atlantic Rainforest.

    PubMed

    Souza, Ursulla P; Ferreira, Fabio C; Carmo, Michele A F; Braga, Francisco M S

    2015-01-01

    In this paper, we determined diet composition, reproductive periodicity and fecundity of Astyanax intermedius in a headwater stream of a State Park of an Atlantic rainforest. We also evaluated the influence of rainfall, water temperature and fish size on niche width and niche overlap. Sampling was conducted monthly throughout one year in the Ribeirão Grande stream, southeastern Brazil. Diet consisted of 31 food items with equal contribution of allochthonous and autochthonous items. Females were larger than males, and the mean sizes at first maturation were 4.44 cm and 3.92 cm, respectively. Based on 212 pairs of mature ovaries, the number of oocytes per female ranged from 538 to 6,727 (mean = 2,688.7). Niche width and niche overlap were not related to rainfall nor water temperature and only niche width increased with fish size, suggesting that as fish grow, more items are included in diet. Our results suggested that A. intermedius fit as a typical opportunistic strategist which may explain the prevalence of this species in several isolated headwater basins of vegetated Atlantic forested streams where food resources are abundant and distributed throughout the year.

  18. Predicting spatial distribution of postfire debris flows and potential consequences for native trout in headwater streams

    USGS Publications Warehouse

    Sedell, Edwin R; Gresswell, Bob; McMahon, Thomas E.

    2015-01-01

    Habitat fragmentation and degradation and invasion of nonnative species have restricted the distribution of native trout. Many trout populations are limited to headwater streams where negative effects of predicted climate change, including reduced stream flow and increased risk of catastrophic fires, may further jeopardize their persistence. Headwater streams in steep terrain are especially susceptible to disturbance associated with postfire debris flows, which have led to local extirpation of trout populations in some systems. We conducted a reach-scale spatial analysis of debris-flow risk among 11 high-elevation watersheds of the Colorado Rocky Mountains occupied by isolated populations of Colorado River Cutthroat Trout (Oncorhynchus clarkii pleuriticus). Stream reaches at high risk of disturbance by postfire debris flow were identified with the aid of a qualitative model based on 4 primary initiating and transport factors (hillslope gradient, flow accumulation pathways, channel gradient, and valley confinement). This model was coupled with a spatially continuous survey of trout distributions in these stream networks to assess the predicted extent of trout population disturbances related to debris flows. In the study systems, debris-flow potential was highest in the lower and middle reaches of most watersheds. Colorado River Cutthroat Trout occurred in areas of high postfire debris-flow risk, but they were never restricted to those areas. Postfire debris flows could extirpate trout from local reaches in these watersheds, but trout populations occupy refugia that should allow recolonization of interconnected, downstream reaches. Specific results of our study may not be universally applicable, but our risk assessment approach can be applied to assess postfire debris-flow risk for stream reaches in other watersheds.

  19. Leaky rivers: Implications of the loss of longitudinal fluvial disconnectivity in headwater streams

    NASA Astrophysics Data System (ADS)

    Wohl, Ellen; Beckman, Natalie D.

    2014-01-01

    Naturally induced longitudinal disconnectivity in the form of channel-spanning logjams creates backwaters along headwater streams that reduce velocity and transport capacity, create at least temporary storage sites for finer sediment and organic matter, and enhance biological processing and uptake of nutrients. Land uses that reduce wood recruitment and instream storage result in reduced stream complexity and increased longitudinal connectivity in headwater rivers. We examine three scales of naturally occurring longitudinal disconnectivity in headwater streams of the Colorado Front Range and the implications for channel process and form of historical alterations in disconnectivity. Basin-scale disconnectivity at channel lengths of 102-103 m results from downstream alternations between steep, narrowly confined valley segments with single-thread channels, and lower gradient, wider, valley segments with multi-thread channels. This variation in valley geometry likely reflects differences in average spacing between joints in bedrock outcrops, which influences bedrock weathering and erosion. Greater volumes of wood stored in the wide valley segments correlate with more closely spaced channel-spanning logjams and greater storage of fine sediments and organic matter. Reach-scale disconnectivity at channel lengths of 101-102 m results from the presence of numerous, closely spaced channel-spanning logjams, which cumulatively store substantial amounts of fine sediment and organic matter. The backwater effects associated with an individual jam can result in the accumulation of up to ~ 11 m3 of fine sediment upstream from the jam, of which as much as 21% is organic matter. Unit-scale disconnectivity at channel lengths of 100-101 m results from the presence of an individual channel-spanning logjam, which locally alters bed gradient, substrate composition, bedform dimensions, and the transport of sediment and organic matter. The transport and storage of instream wood is a

  20. Dissolved organic matter quality and bioavailability changes across an urbanization gradient in headwater streams.

    PubMed

    Hosen, Jacob D; McDonough, Owen T; Febria, Catherine M; Palmer, Margaret A

    2014-07-15

    Landscape urbanization broadly alters watersheds and stream ecosystems, yet the impact of nonpoint source urban inputs on the quantity, quality, and ultimate fate of dissolved organic matter (DOM) is poorly understood. We assessed DOM quality and microbial bioavailability in eight first-order Coastal Plain headwater streams along a gradient of urbanization (i.e., percent watershed impervious cover); none of the streams had point source discharges. DOM quality was measured using fluorescence excitation-emission matrices (EEMs) coupled with parallel factor analysis (PARAFAC). Bioavailability was assessed using biodegradable dissolved organic carbon (BDOC) incubations. Results showed that watershed impervious cover was significantly related to stream DOM composition: increasing impervious cover was associated with decreased amounts of natural humic-like DOM and enriched amounts of anthropogenic fulvic acid-like and protein-like DOM. Microbial bioavailability of DOM was greater in urbanized streams during spring and summer, and was related to decreasing proportions of humic-like DOM and increasing proportions of protein-like DOM. Increased bioavailability was associated with elevated extracellular enzyme activity of the initial microbial community supplied to samples during BDOC incubations. These findings indicate that changes in stream DOM quality due to watershed urbanization may impact stream ecosystem metabolism and ultimately the fate of organic carbon transported through fluvial systems.

  1. Stream Ammonium Uptake Across Scales in Headwater Catchments of a Tropical Rainforest, Luquillo Mountains, Puerto Rico

    NASA Astrophysics Data System (ADS)

    Brereton, R. L.; McDowell, W. H.; Wymore, A.

    2015-12-01

    Many tropical forest streams export high amounts of nitrogen relative to streams draining undisturbed watersheds of other biomes. With their low DOC concentrations and high rates of respiration, headwater streams in the Luquillo Mountains have been previously characterized as energy-limited, suggesting that NH4+ uptake is dominated not by N demand but by energy demand. In the Rio Icacos watershed, high concentrations of NH4+ (>1 mg N/L) are found in groundwater adjacent to the streams, making high inputs of NH4+ to the stream channel via groundwater seepage likely. Stream nutrient spiraling metrics can be used to quantify uptake and retention rates of specific nutrients, and can be measured by solute additions. Tracer Additions for Spiraling Curve Characterization (TASCC) is a recently developed method (Covino et al. 2010) for quantifying nutrient uptake with a single slug addition of nutrient and conservative tracer. Here we present NH4+ uptake metrics from TASCC additions in three Luquillo streams of different sizes, ranging from 2nd to 4th order: the Rio Icacos, a larger, 3rd order tributary and a smaller 2nd order tributary. Background NH4+ concentrations vary by up to an order of magnitude, with highest concentrations (27 μg N/L) found in the smaller tributary. Background DOC concentrations are uniformly low and show no difference between the three streams (500-600 μg C/L). The smaller tributary has the shortest uptake length (155 m) and highest uptake velocity (2.9 mm/min) of the three streams. Unexpectedly, the Rio Icacos has a higher uptake velocity (1.7 mm/min) than the larger tributary (1.0 mm/min), despite having an uptake length more than double (1400 m) that of the larger tributary (596 m). Overall, NH4+ uptake is substantial in all three streams and varies with background concentrations, not stream size.

  2. Instream Wood Loads and Channel Complexity in Headwater Streams Under Alternative Stable States

    NASA Astrophysics Data System (ADS)

    Livers, B.; Wohl, E.

    2014-12-01

    Channel morphology and irregularities in stream boundaries can create zones of flow separation, where lower velocities trap fine sediment and organic matter and increase opportunities for nutrient processing and biological uptake. This effect is most pronounced with channel-spanning structures such as logjams. Humans have changed the spatial and temporal characteristics of wood distribution in streams, with lasting effects on instream wood recruitment, wood loads, logjam distribution, and hydraulic roughness. Previous studies in the Colorado Front Range show that contemporary headwater streams flowing through old-growth, unmanaged forests have more wood than streams flowing through younger-growth, managed forests, but do not evaluate the effects of wood on channel complexity. 'Managed' versus 'unmanaged' refers to whether forests were or are currently exposed to human alteration. Although some alteration has long since ceased, reduced wood loads in managed streams persist. Our primary objective was to quantify differences in logjams, wood volumes, stream complexity, and organic carbon storage on streams with different management and disturbance histories in order to examine legacy effects across a gradient of stream management. Data were collected during the summers of 2013 and 2014 in the Southern Rocky Mountains. The 25 stream reaches studied are 2nd to 3rd order, subalpine streams that are categorized into: old-growth unmanaged forests; younger, naturally disturbed unmanaged forests; and younger managed forests. We assessed instream and floodplain wood loads and logjams and evaluated the role that large wood plays in local channel complexity, pool volume, and storage of organic carbon. Preliminary results show that greatest wood and carbon storage in sediments, as well as channel complexity, occurs in streams in old-growth, unmanaged forests and the least wood and carbon storage and channel complexity occurs in younger-growth, managed forests.

  3. Grazer traits, competition, and carbon sources to a headwater-stream food web.

    PubMed

    McNeely, Camille; Finlay, Jacques C; Power, Mary E

    2007-02-01

    We investigated the effect of grazing by a dominant invertebrate grazer (the caddisfly Glossosoma penitum) on the energy sources used by other consumers in a headwater-stream food web. Stable isotope studies in small, forested streams in northern California have shown that G. penitum larvae derive most of their carbon from algae, despite low algal standing crops. We hypothesized that the caddisfly competes with other primary consumers (including mayflies) for algal food and increases their reliance on terrestrial detritus. Because Glossosoma are abundant and defended from predators by stone cases, their consumption of algal energy may reduce its transfer up the food chain. We removed Glossosoma (natural densities >1000 caddisflies/m2) from five approximately 4 m2) stream sections during the summer of 2000 and measured responses of algae, invertebrate primary consumers, and invertebrate predators. The treatment reduced Glossosoma biomass by 80-90%. We observed a doubling in chlorophyll a per area in sections with reduced Glossosoma abundance and aggregative increases in the biomass of undefended primary consumers. Heptageniid mayfly larvae consumed more algae (as measured by stable carbon isotope ratios and gut content analysis) in caddisfly removal plots at the end of the 60-day experiment, although not after one month. We did not see isotopic evidence of increased algal carbon in invertebrate predators, however. Patterns of caddisfly and mayfly diets in the surrounding watershed suggested that mayfly diets are variable and include algae and detrital carbon in variable proportions, but scraping caddisflies consume primarily algae. Caddisfly and mayfly diets are more similar in larger, more productive streams where the mayflies assimilate more algae. Isotopic analysis, in combination with measurements of macroinvertebrate abundance and biomass in unmanipulated plots, suggested that a substantial portion of the invertebrate community (>50% of biomass) was supported

  4. Active Stream Length Dynamics in Headwater Catchments Spanning Physiographic Provinces in the Appalachian Highlands

    NASA Astrophysics Data System (ADS)

    Jensen, C.; McGuire, K. J.

    2015-12-01

    One of the most basic descriptions of streams is the presence of channelized flow. However, this seemingly simple query goes unanswered for the majority of headwater networks, as stream length expands and contracts with the wetness of catchments seasonally, interannually, and in response to storm events. Although streams are known to grow and shrink, a lack of information on longitudinal dynamics across different geographic regions precludes effective management. Understanding the temporal variation in temporary network length over a broad range of settings is critical for policy decisions that impact aquatic ecosystem health. This project characterizes changes in active stream length for forested headwater catchments spanning four physiographic provinces of the Appalachian Highlands: the New England at Hubbard Brook Experimental Forest, New Hampshire; Valley and Ridge at Poverty Creek and the North Fork of Big Stony Creek in Jefferson National Forest, Virginia; Blue Ridge at Coweeta Hydrologic Laboratory, North Carolina; and Appalachian Plateau at Fernow Experimental Forest, West Virginia. Multivariate statistical analysis confirms these provinces exhibit characteristic topographies reflecting differences in climate, geology, and environmental history and, thus, merit separate consideration. The active streams of three watersheds (<45 ha) in each study area were mapped six times to capture a variety of moderate flow conditions that can be expected most of the time (i.e., exceedance probabilities between 25 to 75%). The geomorphic channel and channel heads were additionally mapped to determine how active stream length variability relates to the development of the geomorphic network. We found that drainage density can vary up to four-fold with discharge. Stream contraction primarily proceeds by increasing disconnection and disintegration into pools, while the number of flow origins remains constant except at high and low extremes of discharge. This work demonstrates

  5. Stable isotope analyses of web-spinning spider assemblages along a headwater stream in Puerto Rico.

    PubMed

    Kelly, Sean P; Cuevas, Elvira; Ramírez, Alonso

    2015-01-01

    Web-spinning spiders that inhabit stream channels are considered specialists of aquatic ecosystems and are major consumers of emerging aquatic insects, while other spider taxa are more commonly found in riparian forests and as a result may consume more terrestrial insects. To determine if there was a difference in spider taxa abundance between riverine web-spinning spider assemblages within the stream channel and the assemblages 10 m into the riparian forest, we compared abundances for all web-spinning spiders along a headwater stream in El Yunque National Forest in northeast Puerto Rico. By using a nonmetric dimensional scaling (NMDS) abundance analysis we were able to see a clear separation of the two spider assemblages. The second objective of the study was to determine if aquatic insects contributed more to the diet of the spider assemblages closest to the stream channel and therefore stable isotope analyses of δ (15)N and δ (13)C for web-spinning spiders along with their possible prey were utilized. The results of the Bayesian mixing model (SIAR) however showed little difference in the diets of riverine (0 m), riparian (10 m) and upland (25 m) spiders. We found that aquatic insects made up ∼50% of the diet for web-spinning spiders collected at 0 m, 10 m, and 25 m from the stream. This study highlights the importance of aquatic insects as a food source for web-spinning spiders despite the taxonomic differences in assemblages at different distances from the stream.

  6. Stable isotope analyses of web-spinning spider assemblages along a headwater stream in Puerto Rico

    PubMed Central

    Cuevas, Elvira; Ramírez, Alonso

    2015-01-01

    Web-spinning spiders that inhabit stream channels are considered specialists of aquatic ecosystems and are major consumers of emerging aquatic insects, while other spider taxa are more commonly found in riparian forests and as a result may consume more terrestrial insects. To determine if there was a difference in spider taxa abundance between riverine web-spinning spider assemblages within the stream channel and the assemblages 10 m into the riparian forest, we compared abundances for all web-spinning spiders along a headwater stream in El Yunque National Forest in northeast Puerto Rico. By using a nonmetric dimensional scaling (NMDS) abundance analysis we were able to see a clear separation of the two spider assemblages. The second objective of the study was to determine if aquatic insects contributed more to the diet of the spider assemblages closest to the stream channel and therefore stable isotope analyses of δ15N and δ13C for web-spinning spiders along with their possible prey were utilized. The results of the Bayesian mixing model (SIAR) however showed little difference in the diets of riverine (0 m), riparian (10 m) and upland (25 m) spiders. We found that aquatic insects made up ∼50% of the diet for web-spinning spiders collected at 0 m, 10 m, and 25 m from the stream. This study highlights the importance of aquatic insects as a food source for web-spinning spiders despite the taxonomic differences in assemblages at different distances from the stream. PMID:26500830

  7. Constraints upon the Response of Fish and Crayfish to Environmental Flow Releases in a Regulated Headwater Stream Network

    PubMed Central

    Chester, Edwin T.; Matthews, Ty G.; Howson, Travis J.; Johnston, Kerrylyn; Mackie, Jonathon K.; Strachan, Scott R.; Robson, Belinda J.

    2014-01-01

    In dry climate zones, headwater streams are often regulated for water extraction causing intermittency in perennial streams and prolonged drying in intermittent streams. Regulation thereby reduces aquatic habitat downstream of weirs that also form barriers to migration by stream fauna. Environmental flow releases may restore streamflow in rivers, but are rarely applied to headwaters. We sampled fish and crayfish in four regulated headwater streams before and after the release of summer-autumn environmental flows, and in four nearby unregulated streams, to determine whether their abundances increased in response to flow releases. Historical data of fish and crayfish occurrence spanning a 30 year period was compared with contemporary data (electrofishing surveys, Victoria Range, Australia; summer 2008 to summer 2010) to assess the longer–term effects of regulation and drought. Although fish were recorded in regulated streams before 1996, they were not recorded in the present study upstream or downstream of weirs despite recent flow releases. Crayfish (Geocharax sp. nov. 1) remained in the regulated streams throughout the study, but did not become more abundant in response to flow releases. In contrast, native fish (Gadopsis marmoratus, Galaxias oliros, Galaxias maculatus) and crayfish remained present in unregulated streams, despite prolonged drought conditions during 2006–2010, and the assemblages of each of these streams remained essentially unchanged over the 30 year period. Flow release volumes may have been too small or have operated for an insufficient time to allow fish to recolonise regulated streams. Barriers to dispersal may also be preventing recolonisation. Indefinite continuation of annual flow releases, that prevent the unnatural cessation of flow caused by weirs, may eventually facilitate upstream movement of fish and crayfish in regulated channels; but other human–made dispersal barriers downstream need to be identified and ameliorated, to allow

  8. Constraints upon the response of fish and crayfish to environmental flow releases in a regulated headwater stream network.

    PubMed

    Chester, Edwin T; Matthews, Ty G; Howson, Travis J; Johnston, Kerrylyn; Mackie, Jonathon K; Strachan, Scott R; Robson, Belinda J

    2014-01-01

    In dry climate zones, headwater streams are often regulated for water extraction causing intermittency in perennial streams and prolonged drying in intermittent streams. Regulation thereby reduces aquatic habitat downstream of weirs that also form barriers to migration by stream fauna. Environmental flow releases may restore streamflow in rivers, but are rarely applied to headwaters. We sampled fish and crayfish in four regulated headwater streams before and after the release of summer-autumn environmental flows, and in four nearby unregulated streams, to determine whether their abundances increased in response to flow releases. Historical data of fish and crayfish occurrence spanning a 30 year period was compared with contemporary data (electrofishing surveys, Victoria Range, Australia; summer 2008 to summer 2010) to assess the longer-term effects of regulation and drought. Although fish were recorded in regulated streams before 1996, they were not recorded in the present study upstream or downstream of weirs despite recent flow releases. Crayfish (Geocharax sp. nov. 1) remained in the regulated streams throughout the study, but did not become more abundant in response to flow releases. In contrast, native fish (Gadopsis marmoratus, Galaxias oliros, Galaxias maculatus) and crayfish remained present in unregulated streams, despite prolonged drought conditions during 2006-2010, and the assemblages of each of these streams remained essentially unchanged over the 30 year period. Flow release volumes may have been too small or have operated for an insufficient time to allow fish to recolonise regulated streams. Barriers to dispersal may also be preventing recolonisation. Indefinite continuation of annual flow releases, that prevent the unnatural cessation of flow caused by weirs, may eventually facilitate upstream movement of fish and crayfish in regulated channels; but other human-made dispersal barriers downstream need to be identified and ameliorated, to allow

  9. Recovery of sediment characteristics in moraine, headwater streams of northern Minnesota after forest harvest

    USGS Publications Warehouse

    Vondracek, Bruce C.; Merten, Eric C.; Hemstad, Nathaniel A.; Kolka, Randall K.; Newman, Raymond M.; Verry, Elon S.

    2010-01-01

    We investigated the recovery of sediment characteristics in four moraine, headwater streams in north-central Minnesota after forest harvest. We examined changes in fine sediment levels from 1997 (preharvest) to 2007 (10 years postharvest) at study plots with upland clear felling and riparian thinning, using canopy cover, proportion of unstable banks, surficial fine substrates, residual pool depth, and streambed depth of refusal as response variables. Basin-scale year effects were significant (p < 0.001) for all responses when evaluated by repeated-measures ANOVAs. Throughout the study area, unstable banks increased for several years postharvest, coinciding with an increase in windthrow and fine sediment. Increased unstable banks may have been caused by forest harvest equipment, increased windthrow and exposure of rootwads, or increased discharge and bank scour. Fine sediment in the channels did not recover by summer 2007, even though canopy cover and unstable banks had returned to 1997 levels. After several storm events in fall 2007, 10 years after the initial sediment input, fine sediment was flushed from the channels and returned to 1997 levels. Although our study design did not discern the source of the initial sediment inputs (e.g., forest harvest, road crossings, other natural causes), we have shown that moraine, headwater streams can require an extended period (up to 10 years) and enabling event (e.g., high storm flows) to recover from large inputs of fine sediment.

  10. Recovery of sediment characteristics in moraine, headwater streams of Northern Minnesota after forest harvest

    USGS Publications Warehouse

    Merten, Eric C.; Hemstad, Nathaniel A.; Kolka, Randall K.; Newman, Raymond M.; Verry, Elon S.; Vondracek, Bruce C.

    2010-01-01

    We investigated the recovery of sediment characteristics in four moraine, headwater streams in north-central Minnesota after forest harvest. We examined changes in fine sediment levels from 1997 (preharvest) to 2007 (10 years postharvest) at study plots with upland clear felling and riparian thinning, using canopy cover, proportion of unstable banks, surficial fine substrates, residual pool depth, and streambed depth of refusal as response variables. Basin-scale year effects were significant (p < 0.001) for all responses when evaluated by repeated-measures ANOVAs. Throughout the study area, unstable banks increased for several years postharvest, coinciding with an increase in windthrow and fine sediment. Increased unstable banks may have been caused by forest harvest equipment, increased windthrow and exposure of rootwads, or increased discharge and bank scour. Fine sediment in the channels did not recover by summer 2007, even though canopy cover and unstable banks had returned to 1997 levels. After several storm events in fall 2007, 10 years after the initial sediment input, fine sediment was flushed from the channels and returned to 1997 levels. Although our study design did not discern the source of the initial sediment inputs (e.g., forest harvest, road crossings, other natural causes), we have shown that moraine, headwater streams can require an extended period (up to 10 years) and enabling event (e.g., high storm flows) to recover from large inputs of fine sediment.

  11. Downstream Warming and Headwater Acidity May Diminish Coldwater Habitat in Southern Appalachian Mountain Streams

    PubMed Central

    Jackson, W. A; Sams, C.

    2015-01-01

    Stream-dwelling species in the U.S. southern Appalachian Mountains region are particularly vulnerable to climate change and acidification. The objectives of this study were to quantify the spatial extent of contemporary suitable habitat for acid- and thermally sensitive aquatic species and to forecast future habitat loss resulting from expected temperature increases on national forest lands in the southern Appalachian Mountain region. The goal of this study was to help watershed managers identify and assess stream reaches that are potentially vulnerable to warming, acidification, or both. To our knowledge, these results represent the first regional assessment of aquatic habitat suitability with respect to the combined effects of stream water temperature and acid-base status in the United States. Statistical models were developed to predict July mean daily maximum water temperatures and air-water temperature relations to determine potential changes in future stream water temperatures. The length of stream considered suitable habitat for acid- and thermally sensitive species, based on temperature and acid neutralizing capacity thresholds of 20°C and 50 μeq/L, was variable throughout the national forests considered. Stream length displaying temperature above 20°C was generally more than five times greater than the length predicted to have acid neutralizing capacity below 50 μeq/L. It was uncommon for these two stressors to occur within the same stream segment. Results suggested that species’ distributional shifts to colder, higher elevation habitats under a warming climate can be constrained by acidification of headwater streams. The approach used in this study can be applied to evaluate climate change impacts to stream water resources in other regions. PMID:26247361

  12. Downstream Warming and Headwater Acidity May Diminish Coldwater Habitat in Southern Appalachian Mountain Streams.

    PubMed

    McDonnell, T C; Sloat, M R; Sullivan, T J; Dolloff, C A; Hessburg, P F; Povak, N A; Jackson, W A; Sams, C

    2015-01-01

    Stream-dwelling species in the U.S. southern Appalachian Mountains region are particularly vulnerable to climate change and acidification. The objectives of this study were to quantify the spatial extent of contemporary suitable habitat for acid- and thermally sensitive aquatic species and to forecast future habitat loss resulting from expected temperature increases on national forest lands in the southern Appalachian Mountain region. The goal of this study was to help watershed managers identify and assess stream reaches that are potentially vulnerable to warming, acidification, or both. To our knowledge, these results represent the first regional assessment of aquatic habitat suitability with respect to the combined effects of stream water temperature and acid-base status in the United States. Statistical models were developed to predict July mean daily maximum water temperatures and air-water temperature relations to determine potential changes in future stream water temperatures. The length of stream considered suitable habitat for acid- and thermally sensitive species, based on temperature and acid neutralizing capacity thresholds of 20°C and 50 μeq/L, was variable throughout the national forests considered. Stream length displaying temperature above 20°C was generally more than five times greater than the length predicted to have acid neutralizing capacity below 50 μeq/L. It was uncommon for these two stressors to occur within the same stream segment. Results suggested that species' distributional shifts to colder, higher elevation habitats under a warming climate can be constrained by acidification of headwater streams. The approach used in this study can be applied to evaluate climate change impacts to stream water resources in other regions.

  13. Assessing mercury exposure and effects to American dippers in headwater streams near mining sites

    USGS Publications Warehouse

    Henny, Charles J.; Kaiser, James L.; Packard, Heidi A.; Grove, Robert A.; Taft, Mike R.

    2005-01-01

    To evaluate mercury (Hg) exposure and possible adverse effects of Hg on American dipper (Cinclus mexicanus) reproduction, we collected eggs and nestling feathers and the larval/nymph form of three Orders of aquatic macroinvertebrates (Ephemeroptera, Plecoptera and Trichoptera = EPT) important in their diet from three major headwater tributaries of the upper Willamette River, Oregon in 2002. The Coast Fork Willamette River is contaminated with Hg due to historical cinnabar (HgS) mining at the Black Butte Mine; the Row River is affected by past gold-mining operations located within the Bohemia Mining District, where Hg was used in the amalgamation process to recover gold; and the Middle Fork Willamette River is the reference area with no known mining. Methyl mercury (MeHg) concentrations (geometric mean) in composite EPT larvae (111.9 ng/g dry weight [dw] or 19.8 ng/g wet weight [ww]), dipper eggs (38.5 ng/g ww) and nestling feathers (1158 ng/g ww) collected from the Coast Fork Willamette were significantly higher than MeHg concentrations in EPT and dipper samples from other streams. Total mercury (THg) concentrations in surface sediments along the same Hg-impacted streams were investigated by others in 1999 (Row River tributaries) and 2002 (Coast Fork). The reported sediment THg concentrations paralleled our biological findings. Dipper breeding territories at higher elevations had fewer second clutches; however, dipper reproductive success along all streams (including the lower elevation and most Hg-contaminated Coast Fork), was judged excellent compared to other studies reviewed. Furthermore, MeHg concentrations in EPT samples from this study were well below dietary concentrations in other aquatic bird species, such as loons and ducks, reported to cause Hg-related reproductive problems. Our data suggest that either dipper feathers or EPT composites used to project MeHg concentrations in dipper feathers (with biomagnification factor of 10a??20??) may be used, but

  14. Assessing mercury exposure and effects to American dippers in headwater streams near mining sites.

    PubMed

    Henny, Charles J; Kaiser, James L; Packard, Heidi A; Grove, Robert A; Taft, Michael R

    2005-10-01

    To evaluate mercury (Hg) exposure and possible adverse effects of Hg on American dipper (Cinclus mexicanus) reproduction, we collected eggs and nestling feathers and the larval/nymph form of three Orders of aquatic macroinvertebrates (Ephemeroptera, Plecoptera and Trichoptera = EPT) important in their diet from three major headwater tributaries of the upper Willamette River, Oregon in 2002. The Coast Fork Willamette River is contaminated with Hg due to historical cinnabar (HgS) mining at the Black Butte Mine; the Row River is affected by past gold-mining operations located within the Bohemia Mining District, where Hg was used in the amalgamation process to recover gold; and the Middle Fork Willamette River is the reference area with no known mining. Methyl mercury (MeHg) concentrations (geometric mean) in composite EPT larvae (111.9 ng/g dry weight [dw] or 19.8 ng/g wet weight [ww]), dipper eggs (38.5 ng/g ww) and nestling feathers (1158 ng/g ww) collected from the Coast Fork Willamette were significantly higher than MeHg concentrations in EPT and dipper samples from other streams. Total mercury (THg) concentrations in surface sediments along the same Hg-impacted streams were investigated by others in 1999 (Row River tributaries) and 2002 (Coast Fork). The reported sediment THg concentrations paralleled our biological findings. Dipper breeding territories at higher elevations had fewer second clutches; however, dipper reproductive success along all streams (including the lower elevation and most Hg-contaminated Coast Fork), was judged excellent compared to other studies reviewed. Furthermore, MeHg concentrations in EPT samples from this study were well below dietary concentrations in other aquatic bird species, such as loons and ducks, reported to cause Hg-related reproductive problems. Our data suggest that either dipper feathers or EPT composites used to project MeHg concentrations in dipper feathers (with biomagnification factor of 10-20x) may be used, but with

  15. Investigation of the Relative Effects of Insolation, Groundwater, and Spatial Variability in Temperature Dynamics of Two Headwater Streams

    NASA Astrophysics Data System (ADS)

    Belica, L.; Caldwell, P. V.; Mitasova, H.; McCarter, J. B.; Smith, J.; Nelson, S. A. C.

    2015-12-01

    Forested headwater streams account for much of the aquatic species diversity and contribute valuable recreational fisheries in the mountains of the Southeastern United States. Stream temperature is key regulator of headwater ecosystems and thermal regime is such a critical factor that it limits where many species can survive, grow, and successfully reproduce. Forested headwater streams are dynamic systems located in complex terrain. The variability of heat exchange between a stream and its surroundings results in thermal variations along its course. Understanding the spatial variability of heat fluxes along headwater streams is important to understanding the thermal dynamics and their effects on the biota. Solar radiation and groundwater inflow are two primary components of the heat budget of headwater streams and are spatially variable over short distances. A comparative analysis of north-facing and south-facing watersheds the Coweeta Basin of the Southern Appalachian Mountains found that temperatures of north-facing streams were cooler than south-facing streams for most of the year, but were warmer in summer. A north-south watershed pair with similar discharge, drainage areas, elevation, slope, and landcover characteristics was selected for further study. Water temperature was monitored longitudinally from the stream origins to the outlets beginning in late 2014. Preliminary data suggested variation in solar radiation resulting from the spatial heterogeneity of evergreen and deciduous trees and seasonal changes in leaf density could explain temperature patterns. We used the Subcanopy Solar Radiation Model, which accounts for topographic and vegetative shading by using a light penetration index derived from LIDAR data, to produce spatially explicit estimates of solar radiation and elucidate spatial and temporal variations in solar radiation along the two streams. Groundwater influence on stream temperature dynamics was investigated using salt-dilution gaging

  16. Barrage fishponds: Reduction of pesticide concentration peaks and associated risk of adverse ecological effects in headwater streams.

    PubMed

    Gaillard, Juliette; Thomas, Marielle; Iuretig, Alain; Pallez, Christelle; Feidt, Cyril; Dauchy, Xavier; Banas, Damien

    2016-03-15

    Constructed wetlands have been suggested as pesticide risk mitigation measures. Yet, in many agricultural areas, ponds or shallow lakes are already present and may contribute to the control of non-point source contamination by pesticides. In order to test this hypothesis, we investigated the influence of extensively managed barrage fishponds (n = 3) on the dissolved concentrations of 100 pesticides in headwater streams over the course of a year. Among the 100 pesticides, 50 different substances were detected upstream and 48 downstream. Highest measured concentration upstream was 26.5 μg/L (2-methyl-4-chlorophenoxyacetic acid, MCPA) and 5.19 μg/L (isoproturon) downstream. Fishponds were found to reduce peak exposure levels as high pesticide concentrations (defined here as ≥ 1 μg/L) generally decreased by more than 90% between upstream and downstream sampling sites. The measured concentrations in the investigated streams were compared to laboratory toxicity data for standard test organisms (algae, invertebrates and fish) using the toxic unit approach. When considering the threshold levels set by the European Union within the first tier risk assessment procedure for pesticide registration (commission regulation (EU) N° 546/2011), regulatory threshold exceedances were observed for 22 pesticides upstream from fishponds and for 9 pesticides downstream. Therefore, the investigated barrage fishponds contributed to the reduction of pesticide peak concentrations and potential risk of adverse effects for downstream ecosystems.

  17. Importance of Stream Denitrification in the Nitrogen Mass Balance of a Midwestern Agricultural Region

    NASA Astrophysics Data System (ADS)

    David, M. B.; Royer, T. V.; Opdyke, M. R.; Tank, J. L.

    2005-05-01

    Agricultural regions of the Midwestern US have large N fluxes as a result of inputs from fertilizer and biological fixation, and outputs through rivers and grain harvest. These inputs and outputs are not balanced, however, and denitrification has been suggested to be an important loss mechanism. We examined the role of in-stream denitrification in the N mass balance of Illinois, a predominantly agricultural region. Nitrate concentrations in streams were often >10 mg nitrate-N L-1, suggesting denitrification was not N-limited throughout most of the year. Denitrification rates were measured at many headwater stream sites throughout the year, in both sediments and primary producer habitat, under different geomorphic conditions. Although in-stream denitrification rates were generally high, hydraulic retention time limited the importance of denitrification in terms of export on an annual basis. Geomorphology was important in explaining rates, but extensive channelization has eliminated most in-stream structures, which could have more effectively reduced stream export of N. Therefore, stream denitrification was only minor sink for N and most nitrate in these headwater sites was exported downstream. In the overall mass balance of N, reservoir and in-field denitrification are thought to be much more important than in-stream denitrification.

  18. The burial of headwater streams in drainage pipes reduces in-stream nitrate retention: results from two US metropolitan areas

    NASA Astrophysics Data System (ADS)

    Beaulieu, J. J.; Mayer, P. M.; Kaushal, S.; Pennino, M. J.; Arango, C. P.; Balz, D. A.; Fritz, K. M.; Golden, H. E.; Knightes, C. D.

    2012-12-01

    Nitrogen (N) retention in stream networks is an important ecosystem service that may be affected by the widespread burial of headwater streams in urban watersheds. Stream burial occurs when segments of a channel are encased in drainage pipe and buried beneath the land surface to facilitate above ground development or stormwater runoff. We predicted that burial suppresses the capacity of streams to retain and transform nitrate, the dominate form of bioavailable N in urban streams, by eliminating primary production, reducing respiration rates, and decreasing water residence time. We tested these predictions by measuring whole-stream nitrate (NO3-) removal rates using 15NO3- isotope tracer releases in reaches that were buried and open to the sunlight in three streams in Cincinnati, Ohio and three streams in Baltimore, Maryland during four seasons. Nitrate uptake lengths in buried reaches (range: 560 - 43,650 m) were 2-98 times greater than open reaches exposed to daylight (range: 85 - 7195 m), indicating that buried reaches were substantially less effective at retaining NO3- than open reaches. Nitrate retention in buried reaches was suppressed by a combination of hydrological and biological processes. High water velocities in buried reaches (buried= 5.8 m/s, open=1.48 m/s) rapidly exported NO3- from the channel, reducing the potential for in-stream NO3- retention. Uptake lengths in the buried reaches were lengthened further by low in-stream biological NO3- demand, as indicated by NO3- uptake velocities 16-fold lower than that of the open reaches. Similarly, buried reaches had lower ecosystem respiration rates than open reaches (buried=1.5g O2/m2/hr, open=4.5g O2/m2/hr), likely due to lower organic matter standing stocks (buried=12 gAFMD/m2, open=48 gAFDM/m2). Biological activity in the buried reaches was further suppressed by the absence of light which precluded photosynthetic activity and the associated assimilative N demand. Overall, our results demonstrate that the

  19. Transport and attenuation of chloroacetanilides in an agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Lefrancq, Marie; Imfeld, Gwenaël; Millet, Maurice; Payraudeau, Sylvain

    2015-04-01

    Chloroacetanilides (e.g., S-metolachlor and acetochlor) are pre-emergent herbicides used on corn and sugar beet and are applied to bare soil, which is prone to runoff and erosion. Some of these herbicides are chiral and the commercial products can be isomerically enriched in the enantiomer-S compared to the enantiomer-R as an example S-metolachlor 80/20% S to R . Determination of the transport of these herbicides in the dissolved and particulate phases of runoff water and degradation in agricultural catchments is currently lacking. The objectives of this study were i) to quantify over an corn growing season the export of chloroacetanilides and their main degradation products (ethane sulfonic (ESA) and oxanilic acid (OXA) degradates of metolachlor (MESA and MOXA) and acetochlor (AcESA and AcOXA)) in an 47 ha agricultural head-catchment in the dissolved and particulate phases, and ii) to evaluate S-metolachlor biodegradation from its application on the field to its export from the catchment using enantiomer analysis. Runoff, erosion, hydrochemistry and chloroacetanilide transport were evaluated at both the plot and catchment scales. Our results showed that an important amount of the pesticide load is missed when only the dissolved concentration of the parent compound is analysed. The total export coefficients for S-metolachlor and acetochlor and their degradation products were 11.4 and 11.8%, respectively, which includes both the dissolved and particulate loads. The partitioning of S-metolachlor and acetochlor between the dissolved and particulate phases varied widely over time and was linked to the suspended solid concentrations. Detection of S-metolachlor degradation products in runoff water was more frequent compared to that of acetochlor degradation products. Enrichment up to 37% of R-metolachlor was observed during the corn growing season, supporting enantioselective degradation of S-metolachlor. Our field study indicates the potential of enantiomer analyses for

  20. Increasing fish taxonomic and functional richness affects ecosystem properties of small headwater prairie streams

    SciTech Connect

    Martin, Erika C.; Gido, Keith B.; Bello, Nora; Dodds, Walter K.; Veach, Allison

    2016-04-06

    Stream fish can regulate their environment through direct and indirect pathways, and the relative influence of communities with different taxonomic and functional richness on ecosystem properties likely depends on habitat structure. Given this complexity, it is not surprising that observational studies of how stream fish communities influence ecosystems have shown mixed results. In this study, we evaluated the effect of an observed gradient of taxonomic (zero, one, two or three species) and functional (zero, one or two groups) richness of fishes on several key ecosystem properties in experimental stream mesocosms. Our study simulated small (less than two metres wide) headwater prairie streams with a succession of three pool-riffle structures (upstream, middle and downstream) per mesocosm. Additionally, ecosystem responses included chlorophyll a from floating algal mats and benthic algae, benthic organic matter, macroinvertebrates (all as mass per unit area), algal filament length and stream metabolism (photosynthesis and respiration rate). Ecosystem responses were analysed individually using general linear mixed models. Significant treatment (taxonomic and functional richness) by habitat (pools and riffles) interactions were found for all but one ecosystem response variable. After accounting for location (upstream, middle and downstream) effects, the presence of one or two grazers resulted in shorter mean algal filament lengths in pools compared to no-fish controls. These observations suggest grazers can maintain short algal filaments in pools, which may inhibit long filaments from reaching the surface. Accordingly, floating algal mats decreased in mid- and downstream locations in grazer treatment relative to no-fish controls. At the scale of the entire reach, gross primary productivity and respiration were greater in treatments with two grazer species compared to mixed grazer/insectivore or control treatments. Lastly, the distribution of stream resources across

  1. Carbon dynamics in the hyporheic zone of a headwater mountain stream in the Cascade Mountains, Oregon

    NASA Astrophysics Data System (ADS)

    Corson-Rikert, Hayley A.; Wondzell, Steven M.; Haggerty, Roy; Santelmann, Mary V.

    2016-10-01

    We investigated carbon dynamics in the hyporheic zone of a steep, forested, headwater catchment western Oregon, USA. Water samples were collected monthly from the stream and a well network during base flow periods. We examined the potential for mixing of different source waters to explain concentrations of DOC and DIC. We did not find convincing evidence that either inputs of deep groundwater or lateral inputs of shallow soil water influenced carbon dynamics. Rather, carbon dynamics appeared to be controlled by local processes in the hyporheic zone and overlying riparian soils. DOC concentrations were low in stream water (0.04-0.09 mM), and decreased with nominal travel time through the hyporheic zone (0.02-0.04 mM lost over 100 h). Conversely, stream water DIC concentrations were much greater than DOC (0.35-0.7 mM) and increased with nominal travel time through the hyporheic zone (0.2-0.4 mM gained over 100 h). DOC in stream water could only account for 10% of the observed increase in DIC. In situ metabolic processing of buried particulate organic matter as well as advection of CO2 from the vadose zone likely accounted for the remaining 90% of the increase in DIC. Overall, the hyporheic zone was a source of DIC to the stream. We suggest that, in mountain stream networks, hyporheic exchange facilitates the transformation of particulate organic carbon buried in floodplains and transports the DIC that is produced back to the stream where it can be evaded to the atmosphere.

  2. Longitudinal Distribution of Wood along Headwater Streams in the Colorado Front Range

    NASA Astrophysics Data System (ADS)

    Wohl, E.; Jaeger, K. L.

    2007-12-01

    Wood loading, channel parameters, and valley parameters were surveyed in 50 contiguous stream segments each 25 m in length along 12 streams in the Colorado Front Range. Length and diameter of each piece of wood were measured, and the orientation of each piece was tallied as a ramp, sunken, bridge, or floater. These data were then used to evaluate basin- and local-scale controls on wood loading, as well as longitudinal patterns of wood distribution in forested headwater streams of the Colorado Front Range. We hypothesized that wood would be non-uniformly distributed as a result of the presence of wood jams and greater numbers of individual pieces in some segments of the stream, and that the degree of non-uniformity would vary among channels in correlation with variations in channel width, gradient, and drainage area as these parameters reflect relative capacity of a stream to transport wood introduced from the adjacent riparian zone and valley bottom. Analyses of the longitudinal uniformity of wood distribution are ongoing. Multiple regression models to evaluate controls on wood loading used either a stream-wide average or data from all 50 segments on each stream. Models that used an average for each of the 12 streams indicated that wood loading correlates most strongly with drainage area, average slope, channel width, and elevation. When all 600 stream segments were included in the multiple regression, the presence of a jam, diameter at breast height (DBH) of trees in the riparian zone, channel width, and stream gradient correlate most strongly with wood loading. Trends in sets of analyses indicate that wood loading is higher for smaller drainage areas, steeper stream gradients, narrower channels, higher elevations, the presence of a jam, and greater DBH values. Each of these correlations is physically reasonable in that smaller drainage areas and narrow channels likely have lower transport capacity, steeper streams and those with jams are hydraulically rougher and

  3. The size distribution of organic carbon in headwater streams in the Amazon basin.

    PubMed

    de Paula, Joana D'Arc; Luizão, Flávio Jesus; Piedade, Maria Teresa Fernandez

    2016-06-01

    Despite the strong representativeness of streams in the Amazon basin, their role in the accumulation of coarse particulate organic carbon (CPOC), fine particulate organic carbon (FPOC), and dissolved organic carbon (DOC) in transport, an important energy source in these environments, is poorly known. It is known that the arboreal vegetation in the Amazon basin is influenced by soil fertility and rainfall gradients, but would these gradients promote local differences in organic matter in headwater streams? To answer this question, 14 low-order streams were selected within these gradients along the Amazon basin, with extensions that varied between 4 and 8 km. The efficiency of the transformation of particulate into dissolved carbon fractions was assessed for each stream. The mean monthly benthic organic matter storage ranged between 1.58 and 9.40 t ha(-1) month(-1). In all locations, CPOC was the most abundant fraction in biomass, followed by FPOC and DOC. Rainfall and soil fertility influenced the distribution of the C fraction (p = 0.01), showing differentiated particulate organic carbon (POC) storage and DOC transportation along the basin. Furthermore, the results revealed that carbon quantification at the basin level could be underestimated, ultimately influencing the global carbon calculations for the region. This is especially due to the fact that the majority of studies consider only fine particulate organic matter and dissolved organic matter, which represent less than 50 % of the stored and transported carbon in streambeds.

  4. Recovery of headwater stream flora following the 1989-1992 groundwater drought

    NASA Astrophysics Data System (ADS)

    Holmes, Nigel T. H.

    1999-02-01

    Over a three year period in spring, summer and autumn from 1993 to 1995 118 sites on 24 headwater reaches of groundwater streams were investigated. Half were also surveyed at least once the previous year. Example rivers were chosen from catchments where there are no abstractions, where there are small or large historical ones, and where reductions or variations in abstractions were likely to occur during the study period.Key objectives of the study were to identify the effects of atypical low flows and bed drying on aquatic and wetland plants following an exceptionally long period of poor groundwater recharge between 1989-92. The extended drought, followed by two years of very good groundwater recharge, provided a unique opportunity to determine the rate, and extent, of recovery. Such knowledge is crucial for conservation bodies, water regulators and water utilities to help them make judgements on the degree of impacts groundwater abstractions have/could have on river flows, and separating these from natural causes.The macrophyte survey data have been used to develop a classification system for headwater streams fed by groundwater. Thirteen different community types were recognised, these giving a clear insight into the flora expected in groundwater streams based primarily on flow periodicity and channel form. Determining the behaviour of individual species helps in environmental assessment of proposed new abstractions, and allows accurate predictions on which ones might decline, be lost or invade. It is equally valuable for predicting the benefits of alleviation strategies based on target flows.Lesser water-parsnip, brook water-crowfoot, blunt-fruited water-starwort and whorl-grass were identified as the most characteristic species of perennial reaches of headwater chalk streams. Pond water-crowfoot only dominates in reaches where flow fails for short periods in late autumn. Marsh foxtail is a classic indicator of winter wet/summer dry flow channels.The River Ver

  5. Export of detritus and invertebrate from headwater streams: linking mountaintop removal and valley fill coal mining to downstream receiving waters

    EPA Science Inventory

    Mountaintop removal and valley fill (MTR/VF) coal mining has resulted in large scale alteration of the topography, reduced forest productivity, and burial of headwater streams in the U.S. Central Appalachians. Although MTR/VF coal mining has occurred for several decades and the ...

  6. Variability in isotopic composition of base flow in two headwater streams of the southern Appalachians

    NASA Astrophysics Data System (ADS)

    Singh, Nitin K.; Emanuel, Ryan E.; McGlynn, Brian L.

    2016-06-01

    We investigated the influence of hillslope scale topographic characteristics and the relative position of hillslopes along streams (i.e., internal catchment structure) on the isotopic composition of base flow in first-order, forested headwater streams at Coweeta Hydrologic Laboratory. The study focused on two adjacent forested catchments with different topographic characteristics. We used stable isotopes (18O and 2H) of water together with stream gauging and geospatial analysis to evaluate relationships between internal catchment structure and the spatiotemporal variability of base flow δ18O. Base flow δ18O was variable in space and time along streams, and the temporal variability of base flow δ18O declined with increasing drainage area. Base flow became enriched in 18O moving along streams from channel heads to catchment outlets but the frequency of enrichment varied between catchments. The spatiotemporal variability in base flow δ18O was high adjacent to large hillslopes with short flow paths, and it was positively correlated with the relative arrangement of hillslopes within the catchment. These results point to influence of unique arrangement of hillslopes on the patterns of downstream enrichment. Spatial variability in base flow δ18O within the streams was relatively low during dry and wet conditions, but it was higher during the transition period between dry and wet conditions. These results suggest that the strength of topographic control on the isotopic composition of base flow can vary with catchment wetness. This study highlights that topographic control on base flow generation and isotopic composition is important even at fine spatial scales.

  7. Seasonal patterns in stream periphyton fatty acids and community benthic algal composition in six high quality headwater streams

    USGS Publications Warehouse

    Honeyfield, Dale C.; Maloney, Kelly O.

    2015-01-01

    Fatty acids are integral components of periphyton and differ among algal taxa. We examined seasonal patterns in periphyton fatty acids in six minimally disturbed headwater streams in Pennsylvania’s Appalachian Mountains, USA. Environmental data and periphyton were collected across four seasons for fatty acid and algal taxa content. Non-metric multidimensional scaling ordination suggested significant seasonal differences in fatty acids; an ordination on algal composition revealed similar seasonal patterns, but with slightly weaker separation of summer and fall. Summer and fall fatty acid profiles were driven by temperature, overstory cover, and conductivity and winter profiles by measures of stream size. Ordination on algal composition suggested that summer and fall communities were driven by overstory and temperature, whereas winter communities were driven by velocity. The physiologically important fatty acid 18:3ω6 was highest in summer and fall. Winter samples had the highest 20:3ω3. Six saturated fatty acids differed among the seasons. Periphyton fatty acids profiles appeared to reflect benthic algal species composition. This suggests that periphyton fatty acid composition can be useful in characterizing basal food resources and stream water quality.

  8. Assessment of climate change and increased atmospheric CO2 impacts on water quality in an intensive agricultural headwater catchment

    NASA Astrophysics Data System (ADS)

    Salmon-Monviola, Jordy; Moreau, Pierre; Benhamou, Cyril; Durand, Patrick; Merot, Philippe; Oehler, François; Gascuel-Odoux, Chantal

    2013-04-01

    Climate change and increasing atmospheric CO2 concentration can lead to disturbances in the global hydrological and nitrogen (N) cycling, and losses in catchment systems. Potential impacts on water and N cycling have been studied in large catchments with a variety of land uses but less attention has focused on agricultural headwater catchments. Despite their relatively small dimensions, headwater catchments of 1-10 km² play a dominant role in N transformations in the landscape, and streams in such catchments may have major impacts on downstream water quantity and quality. This issue is particular important for agricultural catchment which have to reach the WFD targets, where land use changes has to be analysed in combination with climate change. The effects of climate change and rising concentrations of atmospheric CO2 have been studied on (1) changes in hydrological and N balance components on a yearly basis and (2) the seasonal dynamics of water and N fluxes. The spatially distributed agro-hydrological model TNT2 (Topography-based nitrogen Transfers and Transformations) driven by ARPEGE (Action de Recherche Petite Echelle Grande Echelle) climate-model outputs from A1B scenario have been applied on the Kervidy-Naizin headwater catchment (western France), a long term hydrological observatory. Consideration of atmospheric CO2 concentration was implemented at two levels in TNT2: i) to account for the CO2 effect on stomatal conductance TNT2; ii) to consider effect of CO2 on biomass growth. Climate data from ARPEGE model, corrected with the quantile-quantile bias correction method, over 30-year simulation periods were used as TNT2 input (Salmon-Monviola et al., in review). With increased CO2, the main trends in water balance were a significant decrease in annual actual evapotranspiration, a moderate decrease in annual discharge and wetland extent, and a decrease in spring and summer of groundwater recharge and soil water content. Not considering the effects of

  9. Influence of hillslope-channel coupling on two mountain headwater streams, Swiss National Park, Switzerland

    NASA Astrophysics Data System (ADS)

    Schoch, Anna; Hoffmann, Thomas; Dikau, Richard

    2014-05-01

    Sediment fluxes in mountain headwater streams are strongly conditioned by sediment supply from hillslopes and thus hillslope-channel coupling, defined as linkages connecting slopes and channels through sediment transport processes. Sediment supply from hillslopes can have major influences on channel characteristics. The main goal of my research is to achieve a better understanding of these influences on mountain headwater streams in two study areas. This is conducted through the investigation of "channel-reach morphology" according to MONTGOMERY AND BUFFINGTON (1997), morphometric and sedimentological characteristics of the channels and analysis of the slope-channel coupling system. The study was conducted in two valleys in the Swiss National Park, i.e. Val dal Botsch (VdB) and Val Mueschauns (VMu). In both headwaters slopes and channel are coupled effectively due to the small spatial vicinity and frequent debris flow processes connecting the two system components. Both catchments were glaciated in the Pleistocene but show contrasting glacial imprints today. While VdB has a V-shaped morphometry that is dominated by unconsolidated sediments (mainly talus and moraine material), VMu is U-shaped in the upper valley segments and the surface is mainly covered with bedrock. Several methods for data collection and analyses were used: (1) Channel-reach morphology classification, (2) DEM-based analysis of long profiles, ksn-values, slope-area plots and measurement of cross sections in the field, (3) investigation of sedimentological characteristics with pebble counts as well as (4) mapping of recent linkages between slopes and channel and determination of connectivity (effectivity of coupling) using a heuristic approach. The results show that sediment input into both headwater streams is dominated by debris flows. The debris flow catchments, as parts of the slope system, have the highest connectivity to the channels. Channel changes are greatest where debris flows cause

  10. Upland disturbance affects headwater stream nutrients and suspended sediments during baseflow and stormflow

    USGS Publications Warehouse

    Houser, J.N.; Mulholland, P.J.; Maloney, K.O.

    2006-01-01

    Because catchment characteristics determine sediment and nutrient inputs to streams, upland disturbance can affect stream chemistry. Catchments at the Fort Benning Military Installation (near Columbus, Georgia) experience a range of upland disturbance intensities due to spatial variability in the intensity of military training. We used this disturbance gradient to investigate the effects of upland soil and vegetation disturbance on stream chemistry. During baseflow, mean total suspended sediment (TSS) concentration and mean inorganic suspended sediment (ISS) concentration increased with catchment disturbance intensity (TSS: R2 = 0.7, p = 0.005, range = 4.0-10.1 mg L-1; ISS: R2 = 0.71, p = 0.004, range = 2.04-7.3 mg L-1); dissolved organic carbon (DOC) concentration (R2 = 0.79, p = 0.001, range = 1.5-4.1 mg L-1) and soluble reactive phosphorus (SRP) concentration (R2 = 0.75, p = 0.008, range = 1.9-6.2 ??g L-1) decreased with increasing disturbance intensity; and ammonia (NH 4+), nitrate (NO3-), and dissolved inorganic nitrogen (DIN) concentrations were unrelated to disturbance intensity. The increase in TSS and ISS during storms was positively correlated with disturbance (R2 = 0.78 and 0.78, p = 0.01 and 0.01, respectively); mean maximum change in SRP during storms increased with disturbance (r = 0.7, p = 0.04); and mean maximum change in NO3- during storms was marginally correlated with disturbance (r = 0.58, p = 0.06). Soil characteristics were significant predictors of baseflow DOC, SRP, and Ca 2+, but were not correlated with suspended sediment fractions, any nitrogen species, or pH. Despite the largely intact riparian zones of these headwater streams, upland soil and vegetation disturbances had clear effects on stream chemistry during baseflow and stormflow conditions. ?? ASA, CSSA, SSSA.

  11. Upland disturbance affects headwater stream nutrients and suspended sediments during baseflow and stormflow

    SciTech Connect

    Houser, Jeffrey N

    2006-01-01

    Because catchment characteristics determine sediment and nutrient inputs to streams, upland disturbance can affect stream chemistry. Catchments at the Fort Benning Military Installation (near Columbus, Georgia) experience a range of upland disturbance intensities due to spatial variability in the intensity of military training. We used this disturbance gradient to investigate the effects of upland soil and vegetation disturbance on stream chemistry. During baseflow, mean total suspended sediment (TSS) concentration and mean inorganic suspended sediment (ISS) concentration increased with catchment disturbance intensity (TSS: R 2 = 0.7, p = 0.005, range = 4.0-10.1 mg L-1; ISS: R 2 = 0.71, p = 0.004, range = 2.04-7.3 mg L-1); dissolved organic carbon (DOC) concentration (R 2 = 0.79, p = 0.001, range = 1.5-4.1 mg L-1) and soluble reactive phosphorus (SRP) concentration (R 2 = 0.75, p = 0.008, range = 1.9-6.2 {micro}g L-1) decreased with increasing disturbance intensity; and ammonia (NH4 +), nitrate (NO3 -), and dissolved inorganic nitrogen (DIN) concentrations were unrelated to disturbance intensity. The increase in TSS and ISS during storms was positively correlated with disturbance (R 2 = 0.78 and 0.78, p = 0.01 and 0.01, respectively); mean maximum change in SRP during storms increased with disturbance (r = 0.7, p = 0.04); and mean maximum change in NO3 - during storms was marginally correlated with disturbance (r = 0.58, p = 0.06). Soil characteristics were significant predictors of baseflow DOC, SRP, and Ca2+, but were not correlated with suspended sediment fractions, any nitrogen species, or pH. Despite the largely intact riparian zones of these headwater streams, upland soil and vegetation disturbances had clear effects on stream chemistry during baseflow and stormflow conditions.

  12. Impacts of Forest and Agricultural Land Use on Stream Dissolved Organic Carbon During Storms

    NASA Astrophysics Data System (ADS)

    Oh, N. H.; Shin, Y.; Jeon, Y. J.; Lee, E. J.; Eom, J. S.; Kim, B.

    2015-12-01

    Although many studies have been conducted to evaluate the effects of land use on concentrations and compositions of dissolved organic carbon (DOC) in streams and rivers, the relationships are still not clear. To elucidate the impacts of forest and agricultural land use on stream DOC during storm events, we investigated concentrations, optical properties, δ13C, and Δ 14C of DOC in forest and agriculture dominated headwater streams in South Korea. Stream DOC concentrations were the highest in a forested subwatershed, and a significant positive correlation was observed between stream DOC concentrations and the proportion of forested area in watersheds, which was strengthened by increased rain intensity. Four PARAFAC components were extracted including terrestrial humic substances, terrestrial fulvic acids, microbial organic matter, and protein-like organic matter, all of which showed a positive correlation with stream DOC concentration although relative proportion of components were dependent on land use. While DOC in a forest stream was mostly composed of terrestrially derived and 14C-enriched, DOC in an agricultural stream included aged DOC up to ~1,000 years old. Although the impacts of hydrological changes due to irrigation, fertilizer use, and selected crop species were not examined, the results of this study suggest that agricultural land use can be a source of aged terrestrial DOC to streams during summer monsoon storms, potentially changing the balance of the regional carbon cycle.

  13. A view of annual water quality cycle and inter-annual variations in agricultural headwater catchment (Kervidy-Naizin, France)

    NASA Astrophysics Data System (ADS)

    Aubert, A.; Gascuel-odoux, C.; Merot, P.; Grimaldi, C.; Gruau, G.; Ruiz, L.

    2011-12-01

    between hot and cold years and between wet and dry years can mainly be observed during spring and autumn period, i.e. when combining variations of rainfall and temperature. Further jointed statistical analyses between water chemistry and meteorology have to be carried on. References Molenat, J., Gascuel-Odoux, C., Ruiz, L., and Gruau, G. (2008). Role of water table dynamics on stream nitrate export and concentration. in agricultural headwater catchment (France). Journal of Hydrology 348, 363-378. Morel, B., Durand, P., Jaffrezic, A., Gruau, G., and Molenat, J. (2009). Sources of dissolved organic carbon during stormflow in a headwater agricultural catchment. Hydrological Processes 23, 2888-2901.

  14. Visually determined stream mesohabitats influence benthic macroinvertebrate assessments in headwater streams.

    PubMed

    Silva, Déborah R O; Ligeiro, Raphael; Hughes, Robert M; Callisto, Marcos

    2014-09-01

    Mesohabitat components such as substrate and surface flow types are intimately related to benthic macroinvertebrate assemblages in streams. Visual assessments of the distribution of these components provide a means of evaluating physical habitat heterogeneity and aid biodiversity surveys and monitoring. We determined the degree to which stream site and visually assessed mesohabitat variables explain variability (i.e., beta-diversity) in the relative abundance and presence-absence of all macroinvertebrate families and of Ephemeroptera, Plecoptera, and Trichoptera (EPT) genera. We systematically sampled a wide variety of mesohabitat arrangements as they occured in stream sites. We also estimated how much of the explanation given by mesohabitat was associated with substrate or surface flow types. We performed variation partitioning to determine fractions of explained variance through use of partial redundancy analysis (pRDA). Mesohabitats and stream sites explained together from 23 to 32% of the variation in the four analyses. Stream site explained 8-11% of that variation, and mesohabitat variables explained 13-20%. Surface flow types accounted for >60% of the variation provided by the mesohabitat component. These patterns are in accordance with those obtained in previous studies that showed the predominance of environmental variables over spatial location in explaining macroinvertebrate distribution. We conclude that visually assessed mesohabitat components are important predictors of assemblage composition, explaining significant amounts of beta-diversity. Therefore, they are critical to consider in ecological and biodiversity assessments involving macroinvertebrates.

  15. Fish Movement Ecology in High Gradient Headwater Streams: Its Relevance to Fish Passage Restoration through Stream Culvert Barriers

    USGS Publications Warehouse

    Hoffman, Robert L.; Dunham, Jason B.

    2007-01-01

    Executive Summary Restoration of fish passage through culvert barriers has emerged as a major issue in the Pacific Northwest and nationwide. The problem has many dimensions, including the huge number of potential barriers, uncertainty about which structures are actually barriers, the benefits and risks involved with restoration, and the financial costs and timelines. This report attempts to address what we call 'thinking outside of the pipe' in terms of fish passage information needs. This means understanding the value of each potential passage restoration project in the context of other possible projects, and to view individual restoration projects within a larger landscape of habitats and population processes. In this report we provide a brief review of some essential characteristics of animal movement and examples from a focal group of fishes in Washington State: salmon, trout, and char. While several other fishes and many other species use streams where culvert passage barriers may occur, it is the salmonids that are by far the most widespread and in most cases extending furthest into the headwaters of stream networks in Washington. We begin this report by outlining some basic characteristics of animal movement and then apply that foundation to the case of salmonid fishes. Next we consider the consequences of disrupting fish movement with human-constructed barriers, such as culverts. Finally, this body of evidence is summarized and we propose a short list of what we view as high priority information needs to support more effective restoration of fish passage through culverts.

  16. Macroinvertebrate Response to Drought in Undisturbed Headwater Streams of Southwest Georgia.

    NASA Astrophysics Data System (ADS)

    Winn, R. T.; Griswold, M. W.; Golladay, S. W.; Crisman, T. L.

    2005-05-01

    Macroinvertebrates were sampled in four headwater streams for two years (2001-2003) to establish baseline conditions for a study evaluating forestry best management practices. The Palmer Drought Severity Index indicated that the study site experienced a prolonged moderate to severe drought prior to study initiation, with year one of the study characterized as a moderate drought, while year two encompassed drought and initial rainfall recovery. Benthic macroinvertebrates were collected in streams during year one (December 2001/February 2002) and year two (December 2002/February 2003) using a multi-habitat sampling procedure. Individuals were identified to the lowest practical taxonomic level (mostly genus), and metrics including abundance, total number of taxa, and Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa were calculated. Repeated measures ANOVA identified differences in macroinvertebrate assemblages due to sampling period, with lower values for December 2001 relative to February 2003. Abundance and EPT taxa showed an increasing relationship with average daily flow in successive samples of the study. Initiation of drought conditions prior to the study adversely affected species composition (low numbers of EPT taxa and long lived taxa) and trophic structure (co-dominance of shredders, collectors, and predators).

  17. Nitrate loading and CH4 and N2O Flux from headwater streams

    NASA Astrophysics Data System (ADS)

    Schade, J. D.; Bailio, J.; McDowell, W. H.

    2015-12-01

    Freshwater ecosystems transport and process significant amounts of terrestrial carbon and can be considerable sources of CO2, CH4, and N2O. A great deal of uncertainty, however, remains in both global estimates and our understanding of drivers of freshwater greenhouse gas emissions. Furthermore, small headwater streams have received insufficient attention to date and may contribute disproportionately to global GHG flux. Our objective was to quantify GHG flux and assess the impact of changes in DOC and NO3 concentrations in surface and subsurface water on flux rates in three streams in the Lamprey River watershed in New Hampshire, USA, that contrast in surface water DOC:NO3. We measured DOC, NO3 and dissolved gas concentrations in surface waters of each stream monthly from May 2011 to April 2012. Empirical measurements of reaeration coefficients were used to convert dissolved gas concentrations to fluxes. We found higher GHG concentrations and fluxes in the two streams with high DOC concentrations, particularly gases produced by anaerobic metabolism (CH4, N2O from methanogenesis and denitrification, respectively). The stream with high DOC and high NO3 showed high N2O and low CH4 flux, while the high DOC, low NO3 stream showed high CH4 and low N2O flux. Our results are consistent with a model in which C inputs drive total GHG production, while NO3 input regulates the relative importance of CH4 and N2O by suppressing methanogenesis and stimulating denitrification. The magnitude of GHG fluxes suggests that streams in this region are likely to be small sources of CO2, but potentially important sources of CH4 and N2O. Since CH4 and N2O are many times more powerful than CO2 at trapping heat in the atmosphere, freshwater emissions of these gases have the potential to offset a significant proportion of the climate benefits of the terrestrial carbon sink, a possibility that has not been sufficiently incorporated into climate models.

  18. Nitrate loading and CH4 and N2O Flux from headwater streams

    NASA Astrophysics Data System (ADS)

    Sousa, C. H. R. D.; Hilker, T.; Hall, F. G.; Moura, Y. M.; McAdam, E.

    2014-12-01

    Freshwater ecosystems transport and process significant amounts of terrestrial carbon and can be considerable sources of CO2, CH4, and N2O. A great deal of uncertainty, however, remains in both global estimates and our understanding of drivers of freshwater greenhouse gas emissions. Furthermore, small headwater streams have received insufficient attention to date and may contribute disproportionately to global GHG flux. Our objective was to quantify GHG flux and assess the impact of changes in DOC and NO3 concentrations in surface and subsurface water on flux rates in three streams in the Lamprey River watershed in New Hampshire, USA, that contrast in surface water DOC:NO3. We measured DOC, NO3 and dissolved gas concentrations in surface waters of each stream monthly from May 2011 to April 2012. Empirical measurements of reaeration coefficients were used to convert dissolved gas concentrations to fluxes. We found higher GHG concentrations and fluxes in the two streams with high DOC concentrations, particularly gases produced by anaerobic metabolism (CH4, N2O from methanogenesis and denitrification, respectively). The stream with high DOC and high NO3 showed high N2O and low CH4 flux, while the high DOC, low NO3 stream showed high CH4 and low N2O flux. Our results are consistent with a model in which C inputs drive total GHG production, while NO3 input regulates the relative importance of CH4 and N2O by suppressing methanogenesis and stimulating denitrification. The magnitude of GHG fluxes suggests that streams in this region are likely to be small sources of CO2, but potentially important sources of CH4 and N2O. Since CH4 and N2O are many times more powerful than CO2 at trapping heat in the atmosphere, freshwater emissions of these gases have the potential to offset a significant proportion of the climate benefits of the terrestrial carbon sink, a possibility that has not been sufficiently incorporated into climate models.

  19. Effects of insect and decapod exclusion and leaf litter species identity on breakdown rates in a tropical headwater stream.

    PubMed

    Rincón, José; Covich, Alan

    2014-04-01

    High species richness of tropical riparian trees influences the diversity of organic detritus entering streams, creating temporal variability in litter quantity and quality. We examined the influence of species of riparian plants and macroinvertebrate exclusion on leaf-litter breakdown in a headwater stream in the Luquillo Mountains of Puerto Rico. Leaf litter of Dacryodes excelsa (Burseraceae), Guarea guidonia (Meliaceae), Cecropia scheberiana (Moraceae), Manilkara bidentata (Sapotaceae), and Prestoea acuminata (Palmae) were incubated in litter bags in a pool of Quebrada Prieta. Fine mesh bags were used to exclude macroinvertebrates during leaf breakdown, and coarse mesh bags allowed access to decapod crustaceans (juvenile shrimps and crabs) and aquatic insects (mainly mayflies, chironomids, and caddisflies). D. excelsa and G. guidonia (in coarse- and fine-mesh bags) had significantly higher breakdown rates than C. scheberiana, M. bidentata, and P. acuminata. Breakdown rates were significantly faster in coarse-mesh bag treatments for all leaf types, thus indicating a positive contribution of macroinvertebrates in leaf litter breakdown in this headwater stream. After 42 days of incubation, densities of total invertebrates, mayflies and caddisflies, were higher in bags with D. excelsa and G. guidonia, and lower in P. acuminata, C. scheberiana y M. bidentata. Decay rates were positively correlated to insect densities. Our study highlights the importance of leaf identity and macroinvertebrate exclusion on the process of leaf litter breakdown in tropical headwater streams.

  20. Chemical regulation of alpine headwater streams during a storm event (Bogong High Plains, Victoria, Australia)

    NASA Astrophysics Data System (ADS)

    Karis, Terry; Silvester, Ewen; Rees, Gavin

    2016-11-01

    The headwater streams originating in the Australian Alps are the highest water yielding landscape in South-Eastern Australia and are projected to be impacted by climate change through longer dry periods and more episodic rainfall. In this work we studied the major ion and DOC responses of three alpine peatlands (and the broader catchment containing these systems) to a high intensity (summer) storm event. Despite the high volume of rainfall, major ions in stream waters remained strongly chemostatic throughout the event. This was particularly the case for Ca2+ and Mg2+, as well as the alkalinity by association, and suggests that chemical regulation of these particular cations occurs through rapid equilibration processes. DOC concentrations increased during the storm pulse, leading to a shift in alkalinity partitioning from bicarbonate to organic anions and a decrease in pH, mediated by the CO2 saturation levels in the stream water. Our results suggest that alkalinity generation (Ca2+ and Mg2+ acquisition) and partitioning (DOC export) are decoupled processes that may respond differently to repeat storm events depending on the capacity of these systems to provide these constituents. Under extreme case scenarios depletion of DOC (at constant alkalinity) would lead to a smaller pH dip during a storm pulse, while depletion of alkalinity would lead to a larger pH dip, with buffering controlled by free acid. We have not identified the mechanism for the chemostasis of Ca2+ and Mg2+ (and therefore alkalinity) in this work, but this will be critical to understanding the capacity of these peatlands to respond to repeat and more intense storm events.

  1. DOC Dynamics in Small Headwater Streams: the Role of Hydrology, Climate, and Land Management

    NASA Astrophysics Data System (ADS)

    Lajtha, K.; Lee, B. S.; Jones, J. A.

    2015-12-01

    Dissolved organic carbon (DOC) is a critical component of the carbon (C) cycle of both terrestrial and aquatic systems. For small headwater allochthonous streams, terrestrial C delivery fuels the metabolism of receiving waters and significantly influences biotic diversity and function. While nutrient fluxes in streams have long been used as indicators of terrestrial ecosystem processes, less attention has been given to terrestrial controls on DOC export. We used the long-term stream chemistry records from the H.J. Andrews Forest LTER to examine forest management, climatic, and hydrologic controls on both seasonal and annual DOC fluxes. Within a watershed, annual DOC flux was highly related to annual discharge (Q), although considerable variability in higher discharge years suggested a role for indices of storminess, especially early in the water year. Among watersheds, younger, previously harvested watersheds generally had significantly lower DOC fluxes for a given Q than old-growth watersheds, even 4+ decades after harvest. The exception to this pattern was a harvested watershed that had significant downed wood retained on site, and had densities of coarse woody debris (CWD) close to that of the old-growth watersheds even though live tree biomass was similar to the other harvested watersheds. Other climatic factors did not appear to have significant roles in predicting either seasonal or annual fluxes of DOC. This is in sharp contrast to fluxes of nitrate at our site, which appears to be related most significantly to the presence of alder within the watershed. Taken together, our data suggest a persistent and cascading role for CWD in old-growth forest ecosystems.

  2. Diversity of benthic biofilms along a land use gradient in tropical headwater streams, Puerto Rico.

    PubMed

    Burgos-Caraballo, Sofía; Cantrell, Sharon A; Ramírez, Alonso

    2014-07-01

    The properties of freshwater ecosystems can be altered, directly or indirectly, by different land uses (e.g., urbanization and agriculture). Streams heavily influenced by high nutrient concentrations associated with agriculture or urbanization may present conditions that can be intolerable for many aquatic species such as macroinvertebrates and fishes. However, information with respect to how benthic microbial communities may respond to changes in stream ecosystem properties in relation to agricultural or urban land uses is limited, in particular for tropical ecosystems. In this study, diversity of benthic biofilms was evaluated in 16 streams along a gradient of land use at the Turabo watershed in Puerto Rico using terminal restriction fragment length polymorphism. Diversity indices and community structure descriptors (species richness, Shannon diversity, dominance and evenness) were calculated for both bacteria and eukaryotes for each stream. Diversity of both groups, bacteria and eukaryotes, did not show a consistent pattern with land use, since it could be high or low at streams dominated by different land uses. This suggests that diversity of biofilms may be more related to site-specific conditions rather than watershed scale factors. To assess this contention, the relationship between biofilm diversity and reach-scale parameters (i.e., nutrient concentrations, canopy cover, conductivity, and dissolved oxygen) was determined using the Akaike Information Criterion (AIC(c)) for small sample size. Results indicated that nitrate was the variable that best explained variations in biofilm diversity. Since nitrate concentrations tend to increase with urban land use, our results suggest that urbanization may indeed increase microbial diversity indirectly by increasing nutrients in stream water.

  3. Morphology of step-pools in a wilderness headwater stream: The importance of standardizing geomorphic measurements

    NASA Astrophysics Data System (ADS)

    Nickolotsky, Aaron; Pavlowsky, Robert T.

    2007-01-01

    The morphology of step-pools and cascades reflect the geological and climatic factors affecting channels in mountain watersheds. This study uses longitudinal and cross-section surveys to describe a headwater stream in the Boston Mountains of the Ozarks Plateau region in Arkansas and develop morphological relationships for comparisons with other regions. In the Bowers Hollow Creek watershed (3.5 km 2), located within the boundaries of the Upper Buffalo Wilderness Area, step height and wavelength relationships are generally similar to those reported from other regions. Step-pool reaches were widely distributed in a discontinuous manner throughout the watershed. Average values of the sampled reaches are: reach slopes, 0.105 m/m; width, 6.10 m; crest particle sizes, 440 mm; step heights, 0.87 m; and step wavelengths, 6.62 m. The mean step steepness for the watershed was 0.13, whereas the mean length of a reach step to height ratio was 9:1. A comparison of morphological definitions found that the values of step height and steepness can vary by > 30% according to how step parameters are defined. Step height is particularly sensitive; thus, comparison of step height-based relationships from published data requires great care.

  4. Carbon cycling and exports over diel and flood-recovery timescales in a subtropical rainforest headwater stream.

    PubMed

    Looman, Arún; Santos, Isaac R; Tait, Douglas R; Webb, Jackie R; Sullivan, Caroline A; Maher, Damien T

    2016-04-15

    Catchment headwaters comprise the majority of all stream length globally, however, carbon (C) dynamics in these systems remains poorly understood. We combined continuous measurements of pCO2 and radon ((222)Rn, a natural groundwater tracer) with discrete sampling for particulate organic, dissolved organic and inorganic carbon (POC, DOC, and DIC) to assess the short-term carbon dynamics of a pristine subtropical headwater stream in Australia, over contrasting hydrologic regimes of drought, flash-flooding and recovery. Observations over 23days revealed a shift from carbon losses dominated by CO2 outgassing under conditions of low flow (66.4±0.4% of carbon export) to downstream exports of carbon during the flood (87.8±9.7% of carbon export). DOC was the dominant form of downstream exports throughout the study (DOC:DIC:POC=0.82:0.05:0.13). The broadest diel variability among variables occurred during the drought phase, with diel variability up to 662μatmd(-1) (or 27μM[CO2*]d(-1)), 17μMd(-1) and 268Bqm(-3)d(-1) for pCO2, dissolved oxygen and (222)Rn, respectively. Diel dynamics indicated multiple interrelated drivers of stream water chemistry including groundwater seepage and in-stream metabolism. The catchment exported terrestrial carbon throughout the field campaign, with a mean net stream flux of 4.7±7.8mmolCm(-2)(catchment area)d(-1) which is equivalent to 1.4±2.3% of the estimated local terrestrial net primary production. Our observations highlight the importance of accounting for hydrological extremes when assessing the carbon budgets and ecosystem metabolism of headwater streams, and provide a first estimate of aquatic carbon exports from a pristine Australian subtropical rainforest.

  5. Spawning characteristics of redband trout in a headwater stream in Montana

    USGS Publications Warehouse

    Muhlfeld, Clint C.

    2002-01-01

    I investigated the spawning characteristics of redband trout Oncorhynchus mykiss gairdneri (a rainbow trout subspecies) during the spring of 1998 in Basin Creek, a third-order headwater stream located in the Kootenai River drainage in northwestern Montana. I examined the timing of spawning as related to discharge and water temperature and analyzed microhabitat selection of 30 completed redds in a low-gradient (0.5–1.5%) reach. Redband trout spawned as flow declined after peak runoff and as mean daily water temperature exceeded 6.0C and maximum daily temperature exceeded 7.0C. Redband trout began spawning on 6 June (mean daily discharge = 2.1 m3/s), 10 d after the peak discharge (8.7 m3/s) occurred. The last redd was completed on 24 June, when discharge was 1.5 m3/s. The mean total redd length was 53 cm (SD = 14; range = 31–91 cm), and the mean total area was 51 cm2 (SD = 8; range= 46– 76 cm2). Eighty percent of the redds were located in pool tailouts, 13% in runs, and 7% in riffles. Spawning redband trout selected redd sites based on substrate size and water depth but not water velocity. Fish selected substrate sizes of 2–6 mm, water depths of 20–30 cm, and water velocities of 40–70 cm/s. My results suggest that redband trout in a low-gradient, third-order mountain stream found suitable spawning habitat in pool tail-outs that contained abundant gravels.

  6. Use of ESI-FTICR-MS to Characterize Dissolved Organic Matter in Headwater Streams Draining Forest-Dominated and Pasture-Dominated Watersheds

    PubMed Central

    Lu, YueHan; Li, Xiaping; Mesfioui, Rajaa; Bauer, James E.; Chambers, R. M.; Canuel, Elizabeth A.; Hatcher, Patrick G.

    2015-01-01

    Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) has proven to be a powerful technique revealing complexity and diversity of natural DOM molecules, but its application to DOM analysis in grazing-impacted agricultural systems remains scarce. In the present study, we presented a case study of using ESI-FTICR-MS in analyzing DOM from four headwater streams draining forest- or pasture-dominated watersheds in Virginia, USA. In all samples, most formulas were CHO compounds (71.8–87.9%), with other molecular series (CHOS, CHON, CHONS, and CHOP (N, S)) accounting for only minor fractions. All samples were dominated by molecules falling in the lignin-like region (H/C = 0.7–1.5, O/C = 0.1–0.67), suggesting the predominance of allochthonous, terrestrial plant-derived DOM. Relative to the two pasture streams, DOM formulas in the two forest streams were more similar, based on Jaccard similarity coefficients and nonmetric multidimensional scaling calculated from Bray-Curtis distance. Formulas from the pasture streams were characterized by lower proportions of aromatic formulas and lower unsaturation, suggesting that the allochthonous versus autochthonous contributions of organic matter to streams were modified by pasture land use. The number of condensed aromatic structures (CAS) was higher for the forest streams, which is possibly due to the controlled burning in the forest-dominated watersheds and suggests that black carbon was mobilized from soils to streams. During 15-day biodegradation experiments, DOM from the two pasture streams was altered to a greater extent than DOM from the forest streams, with formulas with H/C and O/C ranges similar to protein (H/C = 1.5–2.2, O/C = 0.3–0.67), lipid (H/C = 1.5–2.0, O/C = 0–0.3), and unsaturated hydrocarbon (H/C = 0.7–1.5, O/C = 0–0.1) being the most bioreactive groups. Aromatic compound formulas including CAS were preferentially removed during combined light

  7. Export of Greenhouse Gases Across the Soil/Stream Interface in a Boreal Headwater Stream

    NASA Astrophysics Data System (ADS)

    Oquist, M. G.; Bishop, K. H.; Laudon, H.; Klemedtsson, L.; Nilsson, M. B.

    2015-12-01

    Lateral export of greenhouse gases (GHGs) from groundwater to surface waters is often poorly quantified in GHG budgets of terrestrial ecosystems, including boreal forests. The importance of lateral CO2 export through groundwater for net ecosystem carbon balances is becoming increasingly evident. However, riparian zones in the boreal landscape often exhibit redox characteristics that promote production also of N2O and CH4, that may reach surface waters and add to the total GHG emissions. We estimate annual and seasonal groundwater export of CO2, N2O and CH4 from a boreal forested catchment (11.9 ha) draining into a 1st order stream and quantify the total emission of greenhouse gases across the soil/stream interface. We present annual GHG export for two years, one with annual discharge close to the long-term average and one when discharge was twice as high. During the year with normal discharge export of CO2, N2O and CH4 were 12.3, 0.0015, and 0.00014 g m-2 year-1, respectively, while the export during the wet year was 14.9, 0.001 and 0.0001 g m-2 year-1. In terms of CO2 equivalents the GHG export was dominated by CO2, 96% and 91% for the normal and we year, respectively. Corresponding contributions for N2O were 4% and 9%, respectively, while export of CH4 was <0.1% during both years. While the export of CO2 was evenly distributed between the growing season and the non-growing season, most of the N2O and CH4 export occurred during the non-growing season. Through measurements of groundwater nitrate concentrations the validity of the existing IPCC emission factor EF5-g for N2O emissions was tested. It showed that this emission factor underestimates actual groundwater N2O emissions from the catchment by 2-3 orders of magnitude.

  8. Wood retention and transport in tropical, headwater streams, La Selva Biological Station, Costa Rica

    NASA Astrophysics Data System (ADS)

    Cadol, Daniel; Wohl, Ellen

    2010-11-01

    Wood in tropical streams has the potential to be more mobile than wood in otherwise similar temperate streams because of the warm and humid conditions that promote decay and the more frequent and flashier floods of the tropics. To test this hypothesis, we monitored all large wood pieces for 2.3 years in 10 50-m-long reaches of old-growth headwater streams in La Selva Biological Station, Costa Rica. Annual wood retention rates for pieces ranged from 0.55 to 0.91 among the sites, and retention rates by volume ranged from 0.67 to 0.99. Assuming steady state wood load, which is reasonable for La Selva, these rates are equivalent to mean residence times of 2.2-10.6 years for pieces, and 3.0-83.2 years for a volume of wood. Calculating mean residence time from the weighted average of retention rates gives an average residence time of 4.9 years for a piece of wood and 6.9 years for a volume of wood. These values are less than those reported for old-growth temperate forests, supporting our hypothesis. Mobility of individual pieces was best predicted by piece length relative to stream width ( lr, higher lr led to lower mobility), channel gradient ( s, higher s led to higher mobility), and piece integration into the channel (unattached pieces were 2.6 times more mobile than attached, ramp, or bridge pieces). Temporal variation in retention rates was well explained by variation in peak flow. All four of these factors have also been observed to influence mobility in the temperate zone. The higher mobility of wood in our study site relative to the temperate rainforest of the Pacific Northwest may be explained by the flashy and frequent floods, the high decay rate, or the branching morphology of the native trees; but differentiating the role of these factors, particularly flow and decay, will be complicated by their covariation across climates.

  9. Long-term amelioration of acidity accelerates decomposition in headwater streams.

    PubMed

    Jenkins, Gareth B; Woodward, Guy; Hildrew, Alan G

    2013-04-01

    The secondary production of culturally acidified streams is low, with a few species of generalist detritivores dominating invertebrate assemblages, while decomposition processes are impaired. In a series of lowland headwater streams in southern England, we measured the rate of cellulolytic decomposition and compared it with values measured three decades ago, when anthropogenic acidification was at its peak. We hypothesized that, if acidity has indeed ameliorated, the rate of decomposition will have accelerated, thus potentially supporting greater secondary production and the longer food chains that have been observed in some well-studied recovering freshwater systems. We used cellulose Shirley test cloth as a standardized bioassay to measure the rate of cellulolytic decomposition, via loss in tensile strength, for 31 streams in the Ashdown Forest over 7 days in summer 2011 and 49 days in winter 2012. We compared this with data from an otherwise identical study conducted in 1978 and 1979. In a secondary study, we determined whether decomposition followed a linear or logarithmic decay and, as Shirley cloth is no longer available, we tested an alternative in the form of readily available calico. Overall mean pH had increased markedly over the 32 years between the studies (from 6.0 to 6.7). In both the previous and contemporary studies, the relationship between decomposition and pH was strongest in winter, when pH reaches a seasonal minimum. As in the late 1970s, there was no relationship in 2011/2012 between pH and decay rate in summer. As postulated, decomposition in winter was significantly faster in 2011/2012 than in 1978/1979, with an average increase in decay rate of 18.1%. Recovery from acidification, due to decreased acidifying emissions and deposition, has led to an increase in the rate of cellulolytic decomposition. This response in a critical ecosystem process offers a potential explanation of one aspect of the limited biological recovery that has been

  10. Temporal dynamics between cattle in-stream presence and suspended solids in a headwater catchment.

    PubMed

    Terry, Julie A; McW H Benskin, Clare; Eastoe, Emma F; Haygarth, Philip M

    2014-07-01

    Cattle in-stream activity is potentially an important contributor to water pollution from agriculture. Here we present research on the physical movements of cattle within a stream on suspended solid concentrations (SSC). This study used camera surveillance to monitor the in-stream activity of dairy cattle in an unfenced reach over a four-month period. Results were compared against high-resolution SSC data. Over the days that cattle grazed the field, 57.9% of the instances when SSC crossed the 25 mg l(-1) Freshwater Fish Directive guideline threshold can be attributed to cattle presence in the stream. Flow was the main driver of total sediments transported over the study period, and no relationship was found between SSC and the absolute number of cattle feet in the water. Hysteresis analysis indicated a 'first-flush' of local sediments rapidly mobilised during the non-cattle related SSC events, a result of cattle proximity to channel margins. Results demonstrate a temporal lag between cattle in-stream presence and a critical amount of their contribution to sediment load, and that monitoring only instantaneously with cattle activity may lead to underestimation of their pollution impact.

  11. Hydrochemical analysis of stream water in a tropical, mountainous headwater catchment in northern Thailand

    NASA Astrophysics Data System (ADS)

    Hugenschmidt, C.; Ingwersen, J.; Sangchan, W.; Sukvanachaikul, Y.; Uhlenbrook, S.; Streck, T.

    2010-03-01

    Land use in the vulnerable mountainous parts of the Mae Sa watershed, northern Thailand, has been changed from subsistence agriculture to market-driven production within the past decades. This change is reflected in an increased application of agrochemicals on agricultural areas to secure yields and control pests. Our study site is a steep and fast-responding headwater catchment (77 km2), which transfers agrochemicals that might get lost from soils to waters quickly to the lowlands posing the risk of environmental contamination. This work describes the study, which has been carried out in a subcatchment (7 km2) of the Mae Sa watershed to identify runoff generation processes and contributing flow paths to encircle potential flow paths of pesticides leaching from soil to surface water. We observed three events during the rainy seasons in 2007 and 2008, which were analysed on major ions and EC at high temporal resolution. Based on the samples a two-component hydrograph separation was carried out for three events. For two out of the three events a three-component hydrograph separation was performed to identify the contributions of baseflow, interflow and surface runoff. Baseflow remained the dominant flow fraction, but interflow outshined surface runoff in its amount. Interflow could be observed at the hillslope seeping from the soil in 2007, but not in 2008. We suggest, that interflow highly depends on a constant input of rainfall and requires a certain minimum amount of rainfall per season to be triggered and sustained. Former studies found that pesticides mainly get lost by interflow in this area. Hence, we can point out that pesticide leaching risk is particularly high after a certain amount of rainfall. Critical conditions are therefore mainly present, when the soil layers are close to saturation but not, when these layers are generated or degenerated.

  12. Hyporheic transport in headwater mountain streams is time-invariant in locations where geologic controls dominate hydrologic forcin

    NASA Astrophysics Data System (ADS)

    Ward, A. S.; Schmadel, N.; Wondzell, S. M.; Harman, C. J.; Gooseff, M. N.; Singha, K.

    2015-12-01

    Transport along riparian and hyporheic flowpaths is generally believed to integrate the responses of streams and aquifers to dynamic hydrological forcing. Although it is generally expected transport along these flow paths is time-variable, such dynamic responses have seldom been demonstrated. Further, we do not understand how hydrological forcing interacts with local geologic setting (i.e., valley and streambed morphology) We conducted a series of four stream solute tracer injections in each of two watersheds with contrasting valley morphology in the H.J. Andrews Experimental Forest, monitoring tracer concentrations in the stream and in a network of shallow wells in each watershed. Time series analyses were used to deconvolve transport along subsurface flowpaths from transport in the stream channel. We found time-invariant hyporheic transport in the narrow, bedrock-constrained valley and near large roughness elements (e.g., steps, logs) in the wider valley bottom despite order of magnitude changes in discharge, suggesting geologic controls dominate hyporheic transport in these locations. In contrast, we observed increases in mean arrival time and temporal variance with decreasing discharge at the riparian-hillslope transition, suggesting hydrological dynamics control transport in these locations. We pose several mechanisms by which dynamic hydrology and geologic setting interact that may explain the observed behavior. We interpret time-invariant transport as an indication that discharge in the surface stream is a poor predictor of exchange along the stream-hyporheic-riparian-hillslope continuum in headwater valleys. As such, models able to account for the transition from geologically-dominated processes in the near-stream subsurface to hydrologically-dominated processes near the hillslope are required to predict transport and fate in valley bottoms of headwater mountain streams.

  13. Hydro-climatic control of stream dissolved organic carbon in headwater catchment

    NASA Astrophysics Data System (ADS)

    Humbert, Guillaume; Jaffrezic, Anne; Fovet, Ophélie; Gruau, Gérard; Durand, Patrick

    2014-05-01

    Dissolved organic matter (DOM) is a key form of the organic matter linking together the water and the carbon cycles and interconnecting the biosphere (terrestrial and marine) and the soil. At the landscape scale, land use and hydrology are the main factors controlling the amount of DOM transferred from soils to the stream. In an intensively cultivated catchment, a recent work using isotopic composition of DOM as a marker has identified two different sources of DOM. The uppermost soil horizons of the riparian wetland appear as a quasi-infinite source while the topsoil of the hillslope forms a limited one mobilized by water-table rise and exported to the stream across the upland-riparian wetland-stream continuum. In addition to the exportation of DOM via water fluxes, climatic factors like temperature and precipitation regulate the DOM production by influencing microbial activity and soil organic matter degradation. The small headwater catchment (5 km²) of Kervidy-Naizin located in Brittany is part of the Environment Research Observatory (ORE) AgrHys. Weather and the hydro-chemistry of the stream, and the groundwater levels are daily recorded since 1993, 2000 and 2001 respectively. Over 13 contrasted hydrological years, the annual flow weighted mean concentration of dissolved organic carbon (DOC) is 5.6 mg.L-1 (sd = 0.7) for annual precipitation varying from 488mm to 1327mm and annual mean temperatures of 11°C (sd = 0.6). Based on this considerable dataset and this annual variability, we tried to understand how the hydro-climatic conditions determinate the stream DOC concentrations along the year. From the fluctuations of water table depth, each hydrologic year has been divided into three main period: i) progressive rewetting of the riparian wetland soils, ii) rising and holding high of the water table in the hillslope, iii) drawdown of the water-table, with less and less topsoil connected to the stream. Within each period base flow and storm flow data were first

  14. Distribution of Brook Trout and Their Food Sources in Meadow vs. Wooded Areas of Sierra Nevada Headwater Streams

    NASA Astrophysics Data System (ADS)

    Basile, N. J.; Blumenshine, S.

    2005-05-01

    Stocked eastern brook trout are now well established in historically fishless, small headwater streams in the Sierra Nevada. Although non-native, brook trout have maintained healthy populations since stocking ended 60-80 years ago. Our primary research question was whether brook trout distribution and feeding ecology is influenced by variation in headwater stream habitats and food sources. Stream habitat characteristics and trout demographic data were collected during June and August 2004 from four forested and three meadow sites among five tributaries to Bull Creek in the Sierra Nevada. Both mean fish mass and total fish biomass were greater in forested versus meadow reaches. Macroinvertebrate drift rate did not differ between meadow versus wooded reaches, but were greater in June than August. However, despite higher fish biomass, trout in forests apparently selected prey from drift, whereas trout diets in meadows reflected availability in drift. The results of this research will ultimately be used in a larger, collaborative, whole-ecosystem study conducted by the USDA-Forest Service addressing how current forest management practices affect stream ecosystems.

  15. Biotic drivers of anastomosing channel pattern in headwater streams of the Colorado Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Wohl, E. E.

    2010-12-01

    Most of the headwater rivers in the Colorado Rocky Mountains, USA occur as single channels in steep, narrow valleys. Where variations in bedrock erodibility create segments of wider, lower gradient valleys, however, anastomosing channels can occur if one of two biotic drivers is present. Where a disturbance such as a forest fire or windstorm allows pioneer woody species to colonize valley bottoms, beavers can establish colonies. Beavers build dams that enhance overbank flooding and raise the local water table, limiting the return of conifers and promoting aspen-willow (Populus-Salix) forests that provide food for the beavers. Beavers facilitate the formation of multiple channels by digging small canal-like features across the floodplain and by damming the main channel and promoting channel avulsion. In old-growth conifer forests, channel-spanning logjams can enhance overbank flows that facilitate the development of multiple (sub)parallel channels that extend for 50-300 m downstream. Enhanced overbank flows and multiple channels increase the retention of instream wood, creating a self-enhancing feedback of more jams. At least two thresholds must be crossed for anastomosing driven by logjams to develop; a valley morphology threshold and a wood load threshold. Anastomosing channels are present where stream gradient < 4% and the ratio of (channel width/valley-bottom width) < 0.2; only single channels flow through old-growth forests in valley segments that are steeper and narrower. The average wood piece diameter in old-growth anastomosing channel segments > 20 cm, whereas average piece diameter in forests that have not been disturbed in a century is 10-20 cm; channels in these younger forests do not exhibit anastomosing planforms. Wood load in old-growth anastomosing channels averages 200 m3/ha; old-growth and younger forest single channels average < 100 m3/ha.

  16. Agricultural Intensification in the Amazon: Tracking Nitrogen Fertilizer from Soy-Maize Double Cropping to Streams

    NASA Astrophysics Data System (ADS)

    Cabrera, V. D.; Jankowski, K.; Neill, C.; Macedo, M.; Deegan, L.; Brando, P. M.; Nascimento, S.; Nascimento, E.; Rocha, S.; Coe, M. T.; Nunes, D.

    2015-12-01

    Globalization and the increasing demand for food create pressure to both expand and intensify agriculture. These changes have potentially large consequences for the solute concentrations and functioning of streams. In the Brazilian Amazon, crop agriculture expanded greatly during the last 20 years. More recently, farmers have intensified production on existing cropland by double cropping of soy and maize during the same year. Maize, a novel crop for the region, requires much higher applications of nitrogen (N) fertilizer than soybeans. To determine whether this novel land use and associated N addition influenced N concentrations in groundwater and stream water, we measured N concentrations in groundwater wells and streams from small headwater watersheds across three land uses (soy-maize, soy, and tropical forest) in the Upper Xingu Basin, a region of rapid cropland intensification in the southern Amazon. Each watershed contained six groundwater wells arranged in a transect reaching cropland field edge on either side of the stream. Total inorganic N concentrations were higher in wells adjacent to fields where double cropping occurred, while stream concentrations did not differ overall among land uses. This suggests the riparian zones are critical in the removal of N, but as the intensification of agriculture continues the ability of the riparian zone to prevent N from traveling to streams is unknown. Their protection is critical to the functioning of tropical watersheds.

  17. The impacts of thermokarst on sediment, organic matter, and macroinvertebrate community dynamics in arctic headwater streams

    NASA Astrophysics Data System (ADS)

    Flinn, M.; Kampman, J.; Larouche, J. R.; Bowden, W. B.

    2010-12-01

    Recent research has documented changes in arctic climate that influence permafrost degradation and the incidence of thermokarst formation. In 2009 and 2010, we examined several thermokarst failures on headwater streams near Toolik Lake, AK, and the Kelly River area of the Noatak National Preserve, AK, USA. We quantified significant differences between reference (upstream) and impacted stream reaches affected by these thermokarst features. Sediment deposition at Toolik in 2009, measured with sediment traps, showed no differences in the organic fractions; however, the inorganic fraction was ~2x higher (P<0.05) in the impacted reaches. In 2010, when discharge was lower and less flashy, the pattern reversed and only organic fractions varied between the impacted and reference reach. The patterns of benthic organic matter and fine sediment (stovepipe core) generally showed a 2-fold increase in the impacted reaches indicating that impacts may have a legacy over several years. Significant increases of ammonium (P<0.05) and benthic chlorophyll-a (P<0.01, rock scrubs) were significantly higher in the impacted reaches and increased sharply downstream of the thermokarst, especially in late summer (2009). Benthic macroinvertebrates showed a variable response in abundance and biomass in the impacted reaches. Collector-gatherers (Diptera, Chironomidae) abundance and biomass doubled in the impacted reaches by late summer, mostly due to Dicrotopus, Psudokiefferiella, and Rheotanytarsus. Nemoura (Plecoptera, Nemouridae), a shredding stonefly, abundance and biomass were over 5x higher in the impacted reaches (P<0.01). The increase in the collector-gatherer group was offset by a significant decrease in grazers. Baetis (Ephemeroptera, Baetidae) and Orthocladius (Diptera, Chironomidae) showed a 3-fold decrease in the impacted reaches (P<0.05). Results from several years of research indicate that thermokarst failures result in impacts that respond on different temporal scales. High

  18. Effects of Land Use on Stable Carbon Isotopic Composition and Concentration of Dissolved Organic Carbon (DOC) and Dissolved Inorganic Carbon (DIC) in Southeastern US Piedmont Headwater Streams

    EPA Science Inventory

    Stable carbon isotopic composition (delta 13C) and concentrations of DOC and DIC were measured in stream water samples collected monthly in 15 headwater streams from an area with extensive poultry and cattle production and a rapidly growing human population. Linear regression te...

  19. Long-term trends in stream water and precipitation chemistry at five headwater basins in the northeastern United States

    USGS Publications Warehouse

    Clow, David W.; Mast, M. Alisa

    1999-01-01

    Stream water data from five headwater basins in the northeastern United States covering water years 1968-1996 and precipitation data from eight nearby precipitation monitoring sites covering water years 1984-1996 were analyzed for temporal trends in chemistry using the nonparametric seasonal Kendall test. Concentrations of SO4 declined at three of five streams during 1968,1996 (p < 0.1), and all of the streams exhibited downward trends in SO4 over the second half of the period (1984-1996). Concentrations of SO4 in precipitation declined at seven of eight sites from 1984 to 1996, and the magnitudes of the declines (-0.7 to -2.0 ??eq L-1 yr-1) generally were similar to those of stream water SO4. These results indicate that changes in precipitation SO4 were of sufficient magnitude to account for changes in stream water SO4. Concentrations of Ca + Mg declined at three of five streams and five of eight precipitation sites from 1984 to 1996. Precipitation acidity decreased at five of eight sites during the same period, but alkalinity increased in only one stream. In most cases the decreases in stream water SO4 were similar in magnitude to declines in stream water Ca + Mg, which is consistent with the theory of leaching by mobile acid anions in soils. In precipitation the magnitudes of SO4 declines were similar to those of hydrogen, and declines in Ca + Mg were much smaller. This indicates that recent decreases in SO4 deposition are now being reflected in reduced precipitation acidity. The lack of widespread increases in stream water alkalinity, despite the prevalence of downward trends in Stream water SO4, suggests that at most sites, increases in stream water pH and acid-neutralizing capacity may be delayed until higher soil base-saturation levels are achieved.

  20. Links between riparian landcover, instream environment and fish assemblages in headwater streams of south-eastern Brazil

    USGS Publications Warehouse

    Cruz, Bruna B.; Miranda, Leandro E.; Cetra, Mauricio

    2013-01-01

    We hypothesised and tested a hierarchical organisation model where riparian landcover would influence bank composition and light availability, which in turn would influence instream environments and control fish assemblages. The study was conducted during the dry season in 11 headwater tributaries of the Sorocaba River in the upper Paraná River Basin, south-eastern Brazil. We focused on seven environmental factors each represented by one or multiple environmental variables and seven fish functional traits each represented by two or more classes. Multivariate direct gradient analyses suggested that riparian zone landcover can be considered a higher level causal factor in a network of relations that control instream characteristics and fish assemblages. Our results provide a framework for a hierarchical conceptual model that identifies singular and collective influences of variables from different scales on each other and ultimately on different aspects related to stream fish functional composition. This conceptual model is focused on the relationships between riparian landcover and instream variables as causal factors on the organisation of stream fish assemblages. Our results can also be viewed as a model for headwater stream management in that landcover can be manipulated to influence factors such as bank composition, substrates and water quality, whereas fish assemblage composition can be used as indicators to monitor the success of such efforts.

  1. Seasonal Variation in Floodplain Biogeochemical Processing in a Restored Headwater Stream.

    PubMed

    Jones, C Nathan; Scott, Durelle T; Guth, Christopher; Hester, Erich T; Hession, W Cully

    2015-11-17

    Stream and river restoration activities have recently begun to emphasize the enhancement of biogeochemical processing within river networks through the restoration of river-floodplain connectivity. It is generally accepted that this practice removes pollutants such as nitrogen and phosphorus because the increased contact time of nutrient-rich floodwaters with reactive floodplain sediments. Our study examines this assumption in the floodplain of a recently restored, low-order stream through five seasonal experiments. During each experiment, a floodplain slough was artificially inundated for 3 h. Both the net flux of dissolved nutrients and nitrogen uptake rate were measured during each experiment. The slough was typically a source of dissolved phosphorus and dissolved organic matter, a sink of NO3(-), and variable source/sink of ammonium. NO3(-) uptake rates were relatively high when compared to riverine uptake, especially during the spring and summer experiments. However, when scaled up to the entire 1 km restoration reach with a simple inundation model, less than 0.5-1.5% of the annual NO3(-) load would be removed because of the short duration of river-floodplain connectivity. These results suggest that restoring river-floodplain connectivity is not necessarily an appropriate best management practice for nutrient removal in low-order streams with legacy soil nutrients from past agricultural landuse.

  2. A stream sediment geochemical survey of the Ganga River headwaters in the Garhwal Himalaya

    USGS Publications Warehouse

    Mukherjee, P.K.; Purohit, K.K.; Saini, N.K.; Khanna, P.P.; Rathi, M.S.; Grosz, A.E.

    2007-01-01

    This study models geochemical and adjunct geologic data to define provinces that are favorable for radioactive-mineral exploration. A multi-element bed-sediment geochemical survey of streams was carried out in the headwaters region of the Ganga River in northern India. Overall median values for uranium and thorium (3.6 and 13.8 ppm; maxima of 4.8 and 19.0 ppm and minima of 3.1 and 12.3 ppm respectively) exceed average upper crustal abundances (2.8 and 10.7 ppm) for these radioactive elements. Anomalously high values reach up to 8.3 and 30.1 ppm in thrust zone rocks, and 11.4 and 22.5 ppm in porphyroids. At their maxima, these abundances are nearly four- and three-fold (respectively) enriched in comparison to average crustal abundances for these rock types. Deformed, metamorphosed and sheared rocks are characteristic of the main central thrust zone (MCTZ). These intensively mylonitized rocks override and juxtapose porphyritic (PH) and proterozoic metasedimentary rock sequences (PMS) to the south. Granitoid rocks, the major protoliths for mylonites, as well as metamorphosed rocks in the MCT zone are naturally enriched in radioelements; high values associated with sheared and mylonitized zones are coincident with reports of radioelement mineralization and with anomalous radon concentrations in soils. The radioelement abundance as well as REE abundance shows a northward enrichment trend consistent with increasing grade of metamorphism indicating deformation-induced remobilization of these elements. U and Th illustrate good correlation with REEs but not with Zr. This implies that zircon is not a principal carrier of U and Th within the granitoid-dominant thrust zone and that other radioelement-rich secondary minerals are present in considerable amounts. Thus, the relatively flat, less fractionated, HREE trend is also not entirely controlled by zircon. The spatial correlation of geologic boundary zones (faults, sheared zones) with geochemical and with geophysical (Rn

  3. Geologic, biogeomorphic, and hydrologic controls on floodplain organic carbon retention in mountainous headwater streams of the Colorado Front Range, USA

    NASA Astrophysics Data System (ADS)

    Sutfin, N. A.; Wohl, E.

    2014-12-01

    Unaltered mountainous streams provide insight into natural processes and mechanisms of organic carbon (OC) retention in riparian ecosystems. Our prior work indicates that downed large wood and soil OC are the primary reservoirs for OC storage in mountainous headwaters streams of the Colorado Front Range. We surveyed downed large wood and floodplain soil along 24 study reaches in mountainous headwater streams in and around Rocky Mountain National Park, CO. Comparison of study reaches with various degrees of valley confinement in old growth (>200 yrs) and younger subalpine and montane forests reveals geologic and biogeomorphic controls for OC retention. Preliminary results indicate that unconfined valley segments store much more OC per area (783 Mg/ha) compared to partly confined and confined valley segments (153 Mg/ha). Unconfined valley segments store a significant amount of OC along single thread channels and facilitate potential for development of multithread channels. Multithread channels in old-growth forests, with trees large enough to create persistent channel-spanning logjams, store relatively little sediment and a disproportionately large amount of OC as large wood. Beaver dams also facilitate the development of multithread channels and high soil OC content in beaver meadows constitutes the largest OC pools among all channel types. Preliminary reach-average radiocarbon ages from charcoal in floodplain sediment of three study reaches with drainage areas <20 km2 (1438 ± 84 yBP), 20 - 100 km2 (539 ± 110 yBP), and >100 km2 (887 ± 84 yBP) indicate that floodplain sediment turnover time is much longer in small streams at higher, subalpine elevations. Snowmelt-dominated hydrographs in these high-elevation streams rarely exhibit bimodal characteristics typical of the hydrologic disturbance regime in lower elevation montane forests of the region, which are influenced by large convective thunderstorms and monsoons of the southwestern US. The downstream cumulative

  4. Influence of Inorganic Substrata Size, Leaf Litter and Woody Debris Removal on Benthic Invertebrates Resistance to Floods in Two Contrasting Headwater Streams

    NASA Astrophysics Data System (ADS)

    Bosco Imbert, J.; Gonzalez, Jose Manuel; Basaguren, Ana; Pozo, Jesus

    2005-02-01

    We studied the influence of inorganic substrata size, leaf litter and woody debris removal on the resistance of benthic invertebrates to floods in two contrasting forested headwater streams of the Agüera basin (northern Spain): Cuchillo stream (stream bed dominated by cobbles and pebbles) and Salderrey stream (stream bed dominated by bedrock and boulders). Generally, floods had a greater effect on benthic invertebrates resistance in the Salderrey stream, apparently due to the high presence of loose substrata overlaying bedrock and the higher scouring of sediment in this stream. Unlike Salderrey stream total number of individuals of Simuliidae, Echinogammarus tarragonensis and Protonemura spp. in riffles greatly increased at the reach scale in the Cuchillo stream after two floods, suggesting that Cuchillo was more retentive than Salderrey. A positive relationship between substrata size and invertebrate resistance to floods was found in the Cuchillo stream but not in the Salderrey stream. It appears that the flood disturbances in the Salderrey stream were too strong to find an increase in resistance as substrata size increased. Invertebrate resistance on leaf litter and resistance predictability were also higher in the Cuchillo stream; the former result suggests that retention of leaf packs was greater in the Cuchillo stream. The lack of a statistically significant effect of woody debris removal may imply that the composition and stability of inorganic substrata have more influence on invertebrate resistance to floods than woody debris at the reach scale in these headwater streams dominated by relatively stable substrata.

  5. Hydrologic connectivity increases denitrification in the hyporheic zone and restored floodplains of an agricultural stream

    NASA Astrophysics Data System (ADS)

    Roley, Sarah S.; Tank, Jennifer L.; Williams, Maureen A.

    2012-09-01

    Stream ecotones, specifically the lateral floodplain and subsurface hyporheic zone, can be important sites for nitrogen (N) removal via denitrification, but their role in streams with constructed floodplains has not been examined. We studied denitrification in the hyporheic zone and floodplains of an agriculturally influenced headwater stream in Indiana, USA, that had floodplains added as part of a "two-stage ditch" restoration project. To examine the potential for N removal in the hyporheic zone, we seasonally measured denitrification rates and nitrate concentrations by depth into the stream sediments. We found that nitrate concentration and denitrification rates declined with depth into the hyporheic zone, but denitrification was still measureable to a depth of at least 20 cm. We also measured denitrification rates on the restored floodplains over the course of a flood (pre, during, and post-inundation), and also compared denitrification rates between vegetated and non-vegetated areas of the floodplain. We found that floodplain denitrification rates increased over the course of a floodplain inundation event, and that the presence of surface water increased denitrification rates when vegetation was present. Stream ecotones in midwestern, agriculturally influenced streams have substantial potential for N removal via denitrification, particularly when they are hydrologically connected with high-nitrate surface water.

  6. Evaluation of agricultural best-management practices in the Conestoga River headwaters, Pennsylvania; description and water quality of the Little Conestoga Creek headwaters prior to the implementation of nutrient management

    USGS Publications Warehouse

    Fishel, D.K.; Brown, M.J.; Kostelnik, K.M.; Howse, M.A.

    1992-01-01

    The headwaters of the Conestoga River are being studied to determine the effects of agricultural Best-Management Practices on surface-water and ground-water quality. As part of this study, a 5.82-square-mile area of the Little Conestoga Creek headwaters (Small Watershed) was monitored during 1984-86, prior to implementation of Best-Management Practices. This report describes the land use and hydrology of this study area and characterizes its surface-water and ground-water quality during the pre-Best-Management Practice phase. During base-flow conditions, median concentrations of dissolved nitrite plus nitrate nitrogen as nitrogen increased from 2.7 to 8.1 milligrams per liter as the stream flowed through the intensively-farmed carbonate valley. Median total phosphorus increased from 0.05 to 0.20 milligram per liter. Concentrations of dissolved nitrate nitrogen as nitrogen measured in ground water in carbonate rocks in the valley were as great as 25 milligrams per liter and consistently exceeded 10 milligrams per liter. Statistical analysis showed that it will require substantial reductions in concentrations and discharges of nitrogen and phosphorus in base flow to obtain statistically measurable improvements in water quality. If concentrations and discharges of total nitrogen in base flow at the five sites are reduced by 15 to 33 percent, and by 63 to 70 percent, respectively, then the Wilcoxon Mann-Whitney rank-sum test will be able to detect an improvement in water quality 95 percent of the time. Likewise, if concentrations of total phosphorus are reduced by 36 to 54 percent, or discharges of total phosphorus are reduced by 52 to 69 percent at the five sites, then an improvement in water quality will be able to be detected 95 percent of the time.

  7. Using microbiological tracers to assess the impact of winter land use restrictions on the quality of stream headwaters in a small catchment.

    PubMed

    Flynn, Raymond M; Deakin, Jenny; Archbold, Marie; Cushnan, Hugh; Kilroy, Kate; O'Flaherty, Vincent; Misstear, Bruce D

    2016-01-15

    Diverse land use activities can elevate risk of microbiological contamination entering stream headwaters. Spatially distributed water quality monitoring carried out across a 17 km(2) agricultural catchment aimed to characterize microbiological contamination reaching surface water and investigate whether winter agricultural land use restrictions proved effective in addressing water quality degradation. Combined flow and concentration data revealed no significant difference in fecal indicator organism (FIO) fluxes in base flow samples collected during the open and prohibited periods for spreading organic fertilizer, while relative concentrations of Escherichia coli, fecal streptococci and sulfite reducing bacteria indicated consistently fresh fecal pollution reached aquatic receptors during both periods. Microbial source tracking, employing Bacteroides 16S rRNA gene markers, demonstrated a dominance of bovine fecal waste in river water samples upstream of a wastewater treatment plant discharge during open periods. This contrasted with responses during prohibited periods where human-derived signatures dominated. Differences in microbiological signature, when viewed with hydrological data, suggested that increasing groundwater levels restricted vertical infiltration of effluent from on-site wastewater treatment systems and diverted it to drains and surface water. Study results reflect seasonality of contaminant inputs, while suggesting winter land use restrictions can be effective in limiting impacts of agricultural wastes to base flow water quality.

  8. Channel and perennial flow initiation in headwater streams: management implications of variability in source-area size.

    PubMed

    Jaeger, Kristin L; Montgomery, David R; Bolton, Susan M

    2007-11-01

    Despite increasing attention to management of headwater streams as sources of water, sediment, and wood to downstream rivers, the extent of headwater channels and perennial flow remain poorly known and inaccurately depicted on topographic maps and in digital hydrographic data. This study reports field mapping of channel head and perennial flow initiation locations in forested landscapes underlain by sandstone and basalt lithologies in Washington State, USA. Contributing source areas were delineated for each feature using a digital elevation model (DEM) as well as a Global Positioning System device in the field. Systematic source area-slope relationships described in other landscapes were not evident for channel heads in either lithology. In addition, substantial variability in DEM-derived source area sizes relative to field-delineated source areas indicates that in this area, identification of an area-slope relationship, should one even exist, would be difficult. However, channel heads and stream heads, here defined as the start of perennial flow, appear to be co-located within both of the lithologies, which together with lateral expansion and contraction of surface water around channel heads on a seasonal cycle in the basalt lithology, suggest a controlling influence of bedrock springs for that location. While management strategies for determining locations of channel heads and perennial flow initiation in comparable areas could assign standard source area sizes based on limited field data collection within that landscape, field-mapped source areas that support perennial flow are much smaller than recognized by current Washington State regulations.

  9. An Assessment of Cellulose Filters as a Standardized Material for Measuring Litter Breakdown in Headwater Streams

    EPA Science Inventory

    The decay rate of cellulose filters and associated chemical and biological characteristics were compared to those of white oak (Quercus alba) leaves to determine if cellulose filters could be a suitable standardized material for measuring deciduous leaf breakdown in headwater str...

  10. An assessment of cellulose filters as a standardized material for measuring litter breakdown in headwater streams

    EPA Science Inventory

    The decay rate of cellulose filters and associated chemical and biological characteristics were compared to those of white oak (Quercus alba) leaves to determine if cellulose filters could be a suitable standardized material for measuring deciduous leaf breakdown in headwater str...

  11. Long-term effects on nitrogen and benthic fauna of extreme weather events: Examples from two Swedish headwater streams.

    PubMed

    Löfgren, Stefan; Grandin, Ulf; Stendera, Sonja

    2014-01-01

    Climate change is expected to cause an increased frequency of extreme events such as heavy floods and major storms. Such stochastic events have an immediate impact on surface water quality, but the long-term effects are largely unknown. In this study, we assess long-term monitoring data from two Swedish headwater catchments affected by extreme weather events. At one site, where nitrogen effects in soil water, groundwater, and stream water were studied after storm-felling and subsequent forest dieback from bark beetle attack, long-term (> 5 years) but relatively modest (generally <1 mg L⁻¹) increases in ammonium (NH(4)-N) and nitrate (NO(3)-N) concentrations were observed in the various aqueous media. At the other site, where effects on benthic fauna were studied in a stream impacted by extreme geophysical disturbances caused by rainstorm-induced flashflood, only short-term (1 year) effects were revealed both regarding diversity and composition of species.

  12. Composition of riparian litter input regulates organic matter decomposition: Implications for headwater stream functioning in a managed forest landscape.

    PubMed

    Lidman, Johan; Jonsson, Micael; Burrows, Ryan M; Bundschuh, Mirco; Sponseller, Ryan A

    2017-02-01

    Although the importance of stream condition for leaf litter decomposition has been extensively studied, little is known about how processing rates change in response to altered riparian vegetation community composition. We investigated patterns of plant litter input and decomposition across 20 boreal headwater streams that varied in proportions of riparian deciduous and coniferous trees. We measured a suite of in-stream physical and chemical characteristics, as well as the amount and type of litter inputs from riparian vegetation, and related these to decomposition rates of native (alder, birch, and spruce) and introduced (lodgepole pine) litter species incubated in coarse- and fine-mesh bags. Total litter inputs ranged more than fivefold among sites and increased with the proportion of deciduous vegetation in the riparian zone. In line with differences in initial litter quality, mean decomposition rate was highest for alder, followed by birch, spruce, and lodgepole pine (12, 55, and 68% lower rates, respectively). Further, these rates were greater in coarse-mesh bags that allow colonization by macroinvertebrates. Variance in decomposition rate among sites for different species was best explained by different sets of environmental conditions, but litter-input composition (i.e., quality) was overall highly important. On average, native litter decomposed faster in sites with higher-quality litter input and (with the exception of spruce) higher concentrations of dissolved nutrients and open canopies. By contrast, lodgepole pine decomposed more rapidly in sites receiving lower-quality litter inputs. Birch litter decomposition rate in coarse-mesh bags was best predicted by the same environmental variables as in fine-mesh bags, with additional positive influences of macroinvertebrate species richness. Hence, to facilitate energy turnover in boreal headwaters, forest management with focus on conifer production should aim at increasing the presence of native deciduous

  13. Water chemistry in 179 randomly selected Swedish headwater streams related to forest production, clear-felling and climate.

    PubMed

    Löfgren, Stefan; Fröberg, Mats; Yu, Jun; Nisell, Jakob; Ranneby, Bo

    2014-12-01

    From a policy perspective, it is important to understand forestry effects on surface waters from a landscape perspective. The EU Water Framework Directive demands remedial actions if not achieving good ecological status. In Sweden, 44 % of the surface water bodies have moderate ecological status or worse. Many of these drain catchments with a mosaic of managed forests. It is important for the forestry sector and water authorities to be able to identify where, in the forested landscape, special precautions are necessary. The aim of this study was to quantify the relations between forestry parameters and headwater stream concentrations of nutrients, organic matter and acid-base chemistry. The results are put into the context of regional climate, sulphur and nitrogen deposition, as well as marine influences. Water chemistry was measured in 179 randomly selected headwater streams from two regions in southwest and central Sweden, corresponding to 10 % of the Swedish land area. Forest status was determined from satellite images and Swedish National Forest Inventory data using the probabilistic classifier method, which was used to model stream water chemistry with Bayesian model averaging. The results indicate that concentrations of e.g. nitrogen, phosphorus and organic matter are related to factors associated with forest production but that it is not forestry per se that causes the excess losses. Instead, factors simultaneously affecting forest production and stream water chemistry, such as climate, extensive soil pools and nitrogen deposition, are the most likely candidates The relationships with clear-felled and wetland areas are likely to be direct effects.

  14. Photochemical and microbial alteration of dissolved organic matter in temperate headwater streams associated with different land use

    NASA Astrophysics Data System (ADS)

    Lu, Yuehan; Bauer, James E.; Canuel, Elizabeth A.; Yamashita, Youhei; Chambers, R. M.; Jaffé, Rudolf

    2013-06-01

    and microbial transformations of DOM were evaluated in headwater streams draining forested and human-modified lands (pasture, cropland, and urban development) by laboratory incubations. Changes in DOC concentrations, DOC isotopic signatures, and DOM fluorescence properties were measured to assess the amounts, sources, ages, and properties of reactive and refractory DOM under the influence of photochemistry and/or bacteria. DOC in streams draining forest-dominated watersheds was more photoreactive than in streams draining mostly human-modified watersheds, possibly due to greater contributions of terrestrial plant-derived DOC and lower amounts of prior light exposure in forested streams. Overall, the percentage of photoreactive DOC in stream waters was best predicted by the relative content of terrestrial fluorophores. The bioreactivity of DOC was similar in forested and human-modified streams, but variations were correlated with temperature and may be further controlled by the diagenetic status of organic matter. Alterations to DOC isotopes and DOM fluorescence properties during photochemical and microbial incubations were similar between forested and human-modified streams and included (1) negligible effects of microbial alteration on DOC isotopes and DOM fluorescence properties, (2) selective removal of 13C-depleted and 14C-enriched DOC under the combined influence of photochemical and microbial processes, and (3) photochemical alteration of DOM resulting in a preferential loss of terrestrial humic fluorescence components relative to microbial fluorescence components. This study provides a unique comparison of DOC reactivity in a regional group of streams draining forested and human-modified watersheds and indicates the importance of land use on the photoreactivity of DOC exported from upstream watersheds.

  15. Factors affecting distribution of wood, detritus, and sediment in headwater streams draining managed young-growth red alder - Conifer forests in southeast Alaska

    USGS Publications Warehouse

    Gomi, T.; Johnson, A.C.; Deal, R.L.; Hennon, P.E.; Orlikowska, E.H.; Wipfli, M.S.

    2006-01-01

    Factors (riparian stand condition, management regimes, and channel properties) affecting distributions of wood, detritus (leaves and branches), and sediment were examined in headwater streams draining young-growth red alder (Alnus rubra Bong.) - conifer riparian forests (40 years old) remained in channels and provided sites for sediment and organic matter storage. Despite various alder-conifer mixtures and past harvesting effects, the abundance of large wood, fine wood, and detritus accumulations significantly decreased with increasing channel bank-full width (0.5-3.5 m) along relatively short channel distances (up to 700 m). Changes in wood, detritus, and sediment accumulations together with changes in riparian stand characteristics create spatial and temporal variability of in-channel conditions in headwater systems. A component of alder within young-growth riparian forests may benefit both wood production and biological recovery in disturbed headwater stream channels. ?? 2006 NRC.

  16. Flushing of distal hillslopes as an alternative source of stream dissolved organic carbon in a headwater catchment

    USGS Publications Warehouse

    Gannon, John P; Bailey, Scott W.; McGuire, Kevin J.; Shanley, James B.

    2015-01-01

    We investigated potential source areas of dissolved organic carbon (DOC) in headwater streams by examining DOC concentrations in lysimeter, shallow well, and stream water samples from a reference catchment at the Hubbard Brook Experimental Forest. These observations were then compared to high-frequency temporal variations in fluorescent dissolved organic matter (FDOM) at the catchment outlet and the predicted spatial extent of shallow groundwater in soils throughout the catchment. While near-stream soils are generally considered a DOC source in forested catchments, DOC concentrations in near-stream groundwater were low (mean = 2.4 mg/L, standard error = 0.6 mg/L), less than hillslope groundwater farther from the channel (mean = 5.7 mg/L, standard error = 0.4 mg/L). Furthermore, water tables in near-stream soils did not rise into the carbon-rich upper B or O horizons even during events. In contrast, soils below bedrock outcrops near channel heads where lateral soil formation processes dominate had much higher DOC concentrations. Soils immediately downslope of bedrock areas had thick eluvial horizons indicative of leaching of organic materials, Fe, and Al and had similarly high DOC concentrations in groundwater (mean = 14.5 mg/L, standard error = 0.8 mg/L). Flow from bedrock outcrops partially covered by organic soil horizons produced the highest groundwater DOC concentrations (mean = 20.0 mg/L, standard error = 4.6 mg/L) measured in the catchment. Correspondingly, stream water in channel heads sourced in part by shallow soils and bedrock outcrops had the highest stream DOC concentrations measured in the catchment. Variation in FDOM concentrations at the catchment outlet followed water table fluctuations in shallow to bedrock soils near channel heads. We show that shallow hillslope soils receiving runoff from organic matter-covered bedrock outcrops may be a major source of DOC in headwater catchments in forested mountainous regions

  17. On the relative importance of pool morphology and woody debris to distributions of shrimp in a Puerto Rican headwater stream

    USGS Publications Warehouse

    Pyron, M.; Covich, A.P.; Black, R.W.

    1999-01-01

    In this paper, we report the sizes and distributional orientation of woody debris in a headwater rainforest stream in the Luquillo Experimental Forest (LEF), Puerto Rico. We also provide results of a 4-month study of a wood addition experiment designed to increase cover for benthic macroinvertebrates (freshwater shrimp). We added branch-sized woody debris to 20 pools in three streams. We trapped four species of freshwater shrimp (two species of benthic detritivores and two predatory shrimp species) during each of the 4 months following wood additions. An analysis of pool morphology (maximum depth, surface area and volume) provided a useful predictor of shrimp abundances. In general, numbers of shrimps increased with sizes of stream pools. A repeated measures ANOVA demonstrated no effect of woody debris additions on total numbers of shrimp per pool area. Two detritivore species (Atya lanipes, a filter feeder and Xiphocaris elongata, a shredder) decreased in abundance with increased woody debris and there was no statistical relationship between woody debris additions and predators (Macrobrachium carcinus and M. crenulatum). Small woody debris additions may have altered flow velocities that were important to filter-feeding Atya at the microhabitat scale, although the overall velocities within pools were not altered by wood additions. Lower numbers of Atya and Xiphocaris in two of the three streams may result from the occurrence of two predaceous fishes (American eel and mountain mullet) and more predatory Macrobrachium in these streams. One likely interpretation of the results of this study is that the stream pools in these study reaches had sufficient habitat structure provided by numerous rock crevices (among large rocks and boulders) to provide refuge from predators. Addition of woody debris did not add significantly to the existing structure. These results may not apply to stream channels with sand and gravel substrata where crevices and undercut banks are lacking

  18. Dynamics of stream water TOC concentrations in a boreal headwater catchment: Controlling factors and implications for climate scenarios

    NASA Astrophysics Data System (ADS)

    Köhler, S. J.; Buffam, I.; Seibert, J.; Bishop, K. H.; Laudon, H.

    2009-06-01

    SummaryTwo different but complementary modelling approaches for reproducing the observed dynamics of total organic carbon (TOC) in a boreal stream are presented. One is based on a regression analysis, while the other is based on riparian soil conditions using a convolution of flow and concentration. Both approaches are relatively simple to establish and help to identify gaps in the process understanding of the TOC transport from soils to catchments runoff. The largest part of the temporal variation of stream TOC concentrations (4-46 mg L -1) in a forested headwater stream in the boreal zone in northern Sweden may be described using a four-parameter regression equation that has runoff and transformed air temperature as sole input variables. Runoff is assumed to be a proxy for soil wetness conditions and changing flow pathways which in turn caused most of the stream TOC variation. Temperature explained a significant part of the observed inter-annual variability. Long-term riparian hydrochemistry in soil solutions within 4 m of the stream also captures a surprisingly large part of the observed variation of stream TOC and highlights the importance of riparian soils. The riparian zone was used to reproduce stream TOC with the help of a convolution model based on flow and average riparian chemistry as input variables. There is a significant effect of wetting of the riparian soil that translates into a memory effect for subsequent episodes and thus contributes to controlling stream TOC concentrations. Situations with high flow introduce a large amount of variability into stream water TOC that may be related to memory effects, rapid groundwater fluctuations and other processes not identified so far. Two different climate scenarios for the region based on the IPCC scenarios were applied to the regression equation to test what effect the expected increase in precipitation and temperature and resulting changes in runoff would have on stream TOC concentrations assuming that

  19. Impact of Mountaintop Mining/Valley Fill on the Stable Carbon Isotopic Composition and Concentration of Dissolved Organic Carbon and Dissolved Inorganic Carbon in Headwater Streams

    EPA Science Inventory

    Headwater streams are the dominant land-water interface across much of the landscape and provide many important ecological services. Cycling and transport of various carbon fractions, which serve as important food sources for downstream aquatic ecosystems, are among the important...

  20. PREDICTING THE OCCURRENCE OF NUTRIENTS AND PESTICIDES DURING BASE FLOW IN NONTIDAL HEADWATER STREAMS OF THE MID-ATLANTIC COASTAL PLAIN

    EPA Science Inventory

    Water quality in nontidal headwater (first-order) streams of the Mid-Atlantic Coastal Plain (MACP) during base flow in the late winter and spring is related to land use, hydrogeology, and other natural or human influences in contributing watersheds.

  1. A validation study of a rapid field-based rating system for discriminating among flow permanence classes of headwater streams in South Carolina

    EPA Science Inventory

    Rapid field-based protocols for classifying flow permanence of headwater streams are needed to inform timely regulatory decisions. Such an existing method was developed for and has been used in North Carolina since 1997. The method uses ordinal scoring of 26 geomorphology, hydr...

  2. Influence of Land Use on the Stable Carbon Isotopic Composition and Concentration of Dissolved Organic Carbon and Dissolved Inorganic Carbon in Georgia Piedmont Headwater Streams

    EPA Science Inventory

    Headwater streams are the dominant land-water interface across much of the landscape and provide many important ecological services. Cycling and transport of various carbon fractions, which serve as important food sources for downstream aquatic ecosystems, are among the important...

  3. The influence of high magnitude/ low frequency flood events on the spawning habitat of Atlantic salmon in the headwaters of a Scottish stream.

    NASA Astrophysics Data System (ADS)

    Moir, H.; Gibbins, C.; Soulsby, C.; Webb, J.

    2002-12-01

    In upland salmonid spawning streams, a large proportion of sediment supply is generated in steep headwater reaches during low frequency, high magnitude flood events. These events are integral in dictating channel morphology in these streams. Previous work on a number of Scottish upland streams has suggested that material introduced to the channel during these events is the dominant source of salmonid spawning-calibre sediment and, being important in dictating channel morphology through-out the system, key in controlling the distribution of fish habitats. In headwater reaches, salmonid spawning habitat tends to be limited by the quantity and distribution of suitable sediments, the hydraulics of such locations tending to transport gravel-sized material downstream. Data collected on the Allt a' Ghlinne Bhig (an upland tributary of the River Tay, Scotland) has shown that headwater accumulations of gravel as a result of episodic sediment input during large flood events can provide important spawning habitat, although such features are intrinsically unstable. Uptake of these habitats may be disproportionately important to juvenile production. The stream morphology and discharge associated with over 400 incidents of Atlantic salmon spawning were recorded over three consecutive seasons (2000, 2001 and 2002). Two high magnitude flood events in September 2001 and July 2002 resulted in major sediment input to the headwaters, heavily modifying the character of the channel and producing many substantial accumulations of gravel. In the season prior to these events (2000), no spawning was observed in these locations. During the subsequent surveys (2001 and 2002), a significant number of spawning incidents were observed in the headwaters, potentially providing stock to uptake habitat in these important headwater areas. Although stream discharge during the spawning period is known to affect access to headwater reaches, flows between the three study periods were not significantly

  4. Carbon isotope fractionation of dissolved inorganic carbon (DIC) due to outgassing of carbon dioxide from a headwater stream

    USGS Publications Warehouse

    Doctor, D.H.; Kendall, C.; Sebestyen, S.D.; Shanley, J.B.; Ohte, N.; Boyer, E.W.

    2008-01-01

    The stable isotopic composition of dissolved inorganic carbon (??13C-DIC) was investigated as a potential tracer of streamflow generation processes at the Sleepers River Research Watershed, Vermont, USA. Downstream sampling showed ?? 13C-DIC increased between 3-5??? from the stream source to the outlet weir approximately 0??5 km downstream, concomitant with increasing pH and decreasing PCO2. An increase in ??13C-DIC of 2.4 ?? 0??1??? per log unit decrease of excess PCO2 (stream PCO2 normalized to atmospheric PCO2) was observed from downstream transect data collected during snowmelt. Isotopic fractionation of DIC due to CO2 outgassing rather than exchange with atmospheric CO2 may be the primary cause of increased ?? 13C-DIC values downstream when PCO2 of surface freshwater exceeds twice the atmospheric CO2 concentration. Although CO2 outgassing caused a general increase in stream ??13C-DIC values, points of localized groundwater seepage into the stream were identified by decreases in ??13C-DIC and increases in DIC concentration of the stream water superimposed upon the general downstream trend. In addition, comparison between snowmelt, early spring and summer seasons showed that DIC is flushed from shallow groundwater flowpaths during snowmelt and is replaced by a greater proportion of DIC derived from soil CO2 during the early spring growing season. Thus, in spite of effects from CO2 outgassing, ??13C of DIC can be a useful indicator of groundwater additions to headwater streams and a tracer of carbon dynamics in catchments. Copyright ?? 2007 John Wiley & Sons, Ltd.

  5. A method to estimate the impact of clear-cutting on nutrient concentrations in boreal headwater streams.

    PubMed

    Palviainen, Marjo; Finér, Leena; Laurén, Ari; Mattsson, Tuija; Högbom, Lars

    2015-10-01

    Large-scale forestry operations, like clear-cutting, may impair surface water quality if not done with environmental considerations in mind. Catchment and country level estimates of nutrient loads from forestry are generally based on specific export values, i.e., changes in annual exports due to the implemented forestry operations expressed in kg ha(-1). We introduce here a specific concentration approach as a method to estimate the impact of clear-cutting on nutrient concentrations and export in headwater streams. This new method is potentially a more dynamic and flexible tool to estimate nutrient loads caused by forestry, because variation in annual runoff can be taken into account in load assessments. We combined water quality data from eight boreal headwater catchment pairs located in Finland and Sweden, where the effect of clear-cutting on stream water quality has been studied experimentally. Statistically significant specific concentration values could be produced for total nitrogen, nitrate, ammonium, and phosphate. The significant increases in the concentrations of these nutrients occurred between 2 and 6 years after clear-cutting. Significant specific concentration values could not be produced for total phosphorus and total organic carbon with the whole dataset, although in some single studies significant increases in their concentrations after clear-cutting were observed. The presented method enables taking into account variation in runoff, temporal dynamics of effects, and the proportional size of the treated area in load calculations. The number of existing studies considering large site-specific variation in responses to clear-cutting is small, and therefore further empirical studies are needed to improve predictive capabilities of the specific concentration values.

  6. The burial of headwater streams in drainage pipes reduces in-stream nitrate retention: results from two US metropolitan areas

    EPA Science Inventory

    Urbanization causes stream degradation in various ways, but perhaps the most extreme example is the burial of streams in underground storm drains to facilitate above ground development or to promote the rapid conveyance of stormwater. Stream burial is extensive in urban basins (...

  7. Episodic acidification and changes in fish diversity in Pennsylvania headwater streams

    USGS Publications Warehouse

    Heard, R.M.; Sharpe, W.E.; Carline, R.F.; Kimmel, William G.

    1997-01-01

    Current water chemistry and fish communities in 70 Pennsylvania streams were compared with historical records to determine whether fish species richness had declined and, if so, the possible role of acidification. First-, second-, and third-order streams were selected, and stream sites sampled during the 1961-1971 survey were resampled during May and June 1994 in the Appalachian Plateaus province and during June 1995 in the Valley and Ridge province. Stream-flow was measured and a habitat assessment was completed at each site. Dominant bedrock types influencing the stream sampling site were determined for the Appalachian Plateaus streams. Episodic water chemistry was collected for 39 of the 50 Appalachian Plateaus streams and 14 of the 20 Valley and Ridge streams during the winter and spring of 1996. Thirty-eight (76%) streams of the Appalachian Plateaus province and 13 (65%) streams in the Valley and Ridge province had a loss of fish species since the 1961-1971 sampling period. Habitat scores were not related to losses of fish species. Of the 53 streams sampled during runoff episodes 22 (42%) increased in total dissolved aluminum by more than 50 ??g/L, and 31 (58%) streams decreased in pH by 0.5 units or more. Minnows (Cyprinidae) and darters (Percidae) are sensitive to acidity and were the species most often lost. Streams draining watersheds of the Appalachian Plateaus province dominated by Pottsville bedrock had more acidic water quality during base flow and storm flow sampling periods than streams dominated by Pocono bedrock. The results of this study indicate that many Pennsylvania streams have undergone an alarming reduction in fish diversity during the past 25-34 years. In many of these streams the loss in fish diversity may be attributed to episodic acidification.

  8. Tracking Changes in Dissolved Organic Matter Patterns in Perennial Headwater Streams Throughout a Hydrologic Year Using In-situ Sensors and Optical Properties

    NASA Astrophysics Data System (ADS)

    Armstrong, A.; Epting, S.; Hosen, J. D.; Palmer, M.

    2015-12-01

    Dissolved organic matter (DOM) plays a central role in freshwater streams but key questions remain unanswered about temporal patterns in its quantity and composition. DOM in perennial streams in the temperate zone is a complex mixture reflecting a variety of sources such as leached plant material, organic matter from surrounding soils, and microbial processes in the streams themselves. Headwater perennial streams in the Tuckahoe Creek watershed of the Atlantic coastal plain (Maryland, USA) drain a mosaic of land cover types including row crops, forests, and both forested and marshy small depressional wetlands. Wetland-stream surface hydrologic connections generally occur between mid-fall and late spring, coinciding with peak wetland hydrologic expression (i.e. highest groundwater levels and surface inundation extent). When inundated, these wetlands contain high DOM concentrations, and surface connections may serve as conduits for downstream export. We hypothesized that changes in wetland-stream surface hydrologic connectivity would affect patterns of DOM concentration and composition in these streams. We deployed 6 sondes equipped with fluorescent DOM sensors in 4 perennial streams, 1 forested wetland, and the larger downstream channel draining all study sites for the 2015 water year. The 4 headwater streams drain areas containing forested wetlands and have documented temporary channel connections. Combined with baseflow and stormflow sampling, the sondes provided 15 minute estimates of dissolved organic carbon (DOC) concentrations. This resolution provided insights into patterns of DOC concentration across temporal scales from daily rhythms to seasonal changes, during both baseflow and storm conditions. Discrete measurements of absorbance and fluorescence provided information about DOM composition throughout the study. Together these measurements give a detailed record of DOM dynamics in multiple perennial headwater streams for an entire year. This information

  9. Processes and rates of sediment and wood accumulation in headwater streams of the Oregon Coast Range, USA

    USGS Publications Warehouse

    May, Christine L.; Gresswell, Robert E.

    2003-01-01

    Channels that have been scoured to bedrock by debris flows provide unique opportunities to calculate the rate of sediment and wood accumulation in low-order streams, to understand the temporal succession of channel morphology following disturbance, and to make inferences about processes associated with input and transport of sediment. Dendrochronology was used to estimate the time since the previous debris flow and the time since the last stand-replacement fire in unlogged basins in the central Coast Range of Oregon. Debris flow activity increased 42 per cent above the background rate in the decades immediately following the last wildfire. Changes in wood and sediment storage were quantified for 13 streams that ranged from 4 to 144 years since the previous debris flow. The volume of wood and sediment in the channel, and the length of channel with exposed bedrock, were strongly correlated with the time since the previous debris flow. Wood increased the storage capacity of the channel and trapped the majority of the sediment in these steep headwater streams. In the absence of wood, channels that have been scoured to bedrock by a debris flow may lack the capacity to store sediment and could persist in a bedrock state for an extended period of time. With an adequate supply of wood, low-order channels have the potential of storing large volumes of sediment in the interval between debris flows and can function as one of the dominant storage reservoirs for sediment in mountainous terrain.

  10. Efficacy of environmental DNA to detect and quantify Brook Trout populations in headwater streams of the Adirondack Mountains, New York

    USGS Publications Warehouse

    Baldigo, Barry P.; Sporn, Lee Ann; George, Scott D.; Ball, Jacob

    2016-01-01

    Environmental DNA (eDNA) analysis is rapidly evolving as a tool for monitoring the distributions of aquatic species. Detection of species’ populations in streams may be challenging because the persistence time for intact DNA fragments is unknown and because eDNA is diluted and dispersed by dynamic hydrological processes. During 2015, the DNA of Brook Trout Salvelinus fontinalis was analyzed from water samples collected at 40 streams across the Adirondack region of upstate New York, where Brook Trout populations were recently quantified. Study objectives were to evaluate different sampling methods and the ability of eDNA to accurately predict the presence and abundance of resident Brook Trout populations. Results from three-pass electrofishing surveys indicated that Brook Trout were absent from 10 sites and were present in low (<100 fish/0.1 ha), moderate (100–300 fish/0.1 ha), and high (>300 fish/0.1 ha) densities at 9, 11, and 10 sites, respectively. The eDNA results correctly predicted the presence and confirmed the absence of Brook Trout at 85.0–92.5% of the study sites; eDNA also explained 44% of the variability in Brook Trout population density and 24% of the variability in biomass. These findings indicate that eDNA surveys will enable researchers to effectively characterize the presence and abundance of Brook Trout and other species’ populations in headwater streams across the Adirondack region and elsewhere.

  11. Investigating landfill-impacted groundwater seepage into headwater streams using stable carbon isotopes

    NASA Astrophysics Data System (ADS)

    Atekwana, E. A.; Krishnamurthy, R. V.

    2004-07-01

    The impact of landfill contaminated groundwater along a reach of a small stream adjacent to a municipal landfill was investigated using stable carbon isotopes as a tracer. Groundwater below the stream channel, groundwater seeping into the stream, groundwater from the stream banks and stream water were sampled and analysed for dissolved inorganic carbon (DIC) and the isotope ratio of DIC (13CDIC). Representative samples of groundwater seeping into the stream were collected using a device (a seepage well) specifically designed for collecting samples of groundwater seeping into shallow streams with soft sediments. The DIC and 13CDIC of water samples ranged from 52 to 205 mg C/L and -16.9 to +5.7 relative to VPDB standard, respectively. Groundwater from the stream bank adjacent to the landfill and some samples of groundwater below the stream channel and seepage into the stream showed evidence of 13C enriched DIC (δ13CDIC = -2.3 to +5.7), which we attribute to landfill impact. Stream water and groundwater from the stream bank opposite the landfill did not show evidence of landfill carbon (δ13CDIC = -10.0 to -16.9). A simple mixing model using DIC and δ13CDIC showed that groundwater below the stream and groundwater seeping into the stream could be described as a mixture of groundwater with a landfill carbon signature and uncontaminated groundwater. This study suggests that the hyporheic zone at the stream-groundwater interface probably was impacted by landfill contaminated groundwater and may have significant ecological implications for this ecotone.

  12. Flood-hazard analysis of four headwater streams draining the Argonne National Laboratory property, DuPage County, Illinois

    USGS Publications Warehouse

    Soong, David T.; Murphy, Elizabeth A.; Straub, Timothy D.; Zeeb, Hannah L.

    2016-11-22

    Results of a flood-hazard analysis conducted by the U.S. Geological Survey, in cooperation with the Argonne National Laboratory, for four headwater streams within the Argonne National Laboratory property indicate that the 1-percent and 0.2-percent annual exceedance probability floods would cause multiple roads to be overtopped. Results indicate that most of the effects on the infrastructure would be from flooding of Freund Brook. Flooding on the Northeast and Southeast Drainage Ways would be limited to overtopping of one road crossing for each of those streams. The Northwest Drainage Way would be the least affected with flooding expected to occur in open grass or forested areas.The Argonne Site Sustainability Plan outlined the development of hydrologic and hydraulic models and the creation of flood-plain maps of the existing site conditions as a first step in addressing resiliency to possible climate change impacts as required by Executive Order 13653 “Preparing the United States for the Impacts of Climate Change.” The Hydrological Simulation Program-FORTRAN is the hydrologic model used in the study, and the Hydrologic Engineering Center‒River Analysis System (HEC–RAS) is the hydraulic model. The model results were verified by comparing simulated water-surface elevations to observed water-surface elevations measured at a network of five crest-stage gages on the four study streams. The comparison between crest-stage gage and simulated elevations resulted in an average absolute difference of 0.06 feet and a maximum difference of 0.19 feet.In addition to the flood-hazard model development and mapping, a qualitative stream assessment was conducted to evaluate stream channel and substrate conditions in the study reaches. This information can be used to evaluate erosion potential.

  13. Using a Whole-stream Approach to Quantify Headwater Yedoma DOC Processing Rates in NE Siberia, Russia

    NASA Astrophysics Data System (ADS)

    Heslop, J.; Walter Anthony, K. M.; Davydova, A.; Davydov, S. P.; Zimov, N.

    2015-12-01

    Climate warming triggers the release of permafrost organic carbon (OC) via permafrost thaw and erosion, exporting large amounts of terrestrial C to aquatic environments and making previously frozen OC from a range of soil depths available for microbial processing. It is estimated 210-476 Pg C is stored in deep, ice-rich loess-dominated soils referred to as yedoma. Yedoma is extensive in NE Siberia and Alaska, where it underlies an area of over 1,000,000 km2 and averages 25 m in thickness. Recent research suggests ancient (Pleistocene-aged) permafrost OC, such as yedoma OC, is rapidly and preferentially utilized by microbial communities in Arctic headwater streams. We utilized a combination of short-term laboratory incubations and a whole-stream approach to examine permafrost-derived dissolved organic carbon (DOC) uptake, processing, and transport rates in a small stream which drains yedoma uplands in Cherskii, NE Siberia. Short-term incubations were conducted on permafrost leachates mixed with stream water to quantify microbial processing rates of permafrost-derived DOC from leachates made with surface (0-15 cm), shallow (70-100 cm), and deep (<2 m) yedoma sediments. In addition, we conducted whole-stream DOC release experiments to quantify permafrost DOC uptake length, rate, and velocity. DOC composition from samples collected during both the incubations and the nutrient-release experiments was characterized using absorbance measurements (SUVA254 and SR) and florescence spectrometry (EEMs) to quantify how DOC composition correlates to and changes with permafrost DOC bioavailability and processing parameters. Preliminary results suggest DOC processing rates may be highest in leachates made from surface sediments, which receive fresh OC input from modern ecosystems, and from deep sediments, which contain ancient, previously immobile OC. Shallow permafrost OC, which experiences degradation from annual freeze-thaw cycles without receiving fresh OC input, may have the

  14. The Affects of Mountain Top Removal Mining on Headwater Streams in Eastern Kentucky

    NASA Astrophysics Data System (ADS)

    Word, D. A.; Jack, J. D.; Kelley, R.

    2005-05-01

    Mountain Top Removal/Valley Fill (MTR/VF) coal mining is a relatively new coal extraction technology that is widely utilized throughout the Appalachian region. During this process, the mountaintop is blasted away, the coal removed and the leftover material (spoil) is then deposited into the surrounding valleys. The potential negative ecological effects of these operations on stream biodiversity has received some attention but there is little available data on how these fills affect stream functions such as litter decomposition rates. We selected 4 streams draining "retired" MTR/VF sites of various ages in eastern Kentucky (USA) and one stream from an actively mined site. We compared leaf mass loss rates, N dynamics, fungal colonization (as measured by ergosterol) and water chemistry parameters in these streams to three unmined reference streams. Leaf litter mass loss was usually higher in the reference streams while water chemistry parameters such as conductivity, nitrate and TDS were often much higher in the MTR/VF streams. Such differences in stream function and water quality should be considered in permitting decisions and in assessing recovery of streams after mining.

  15. Groundwater flow path dynamics and nitrogen transport potential in the riparian zone of an agricultural headwater catchment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stream riparian zones are often thought of as areas that provide natural remediation for groundwater contaminants, especially agricultural nitrogen (N). While denitrification and vegetative uptake tend to be efficient N removal processes in slow moving shallow groundwater, these mechanisms decrease ...

  16. Assessing impacts of unconventional natural gas extraction on microbial communities in headwater stream ecosystems in Northwestern Pennsylvania.

    PubMed

    Trexler, Ryan; Solomon, Caroline; Brislawn, Colin J; Wright, Justin R; Rosenberger, Abigail; McClure, Erin E; Grube, Alyssa M; Peterson, Mark P; Keddache, Mehdi; Mason, Olivia U; Hazen, Terry C; Grant, Christopher J; Lamendella, Regina

    2014-01-01

    Hydraulic fracturing and horizontal drilling have increased dramatically in Pennsylvania Marcellus shale formations, however the potential for major environmental impacts are still incompletely understood. High-throughput sequencing of the 16S rRNA gene was performed to characterize the microbial community structure of water, sediment, bryophyte, and biofilm samples from 26 headwater stream sites in northwestern Pennsylvania with different histories of fracking activity within Marcellus shale formations. Further, we describe the relationship between microbial community structure and environmental parameters measured. Approximately 3.2 million 16S rRNA gene sequences were retrieved from a total of 58 samples. Microbial community analyses showed significant reductions in species richness as well as evenness in sites with Marcellus shale activity. Beta diversity analyses revealed distinct microbial community structure between sites with and without Marcellus shale activity. For example, operational taxonomic units (OTUs) within the Acetobacteracea, Methylocystaceae, Acidobacteriaceae, and Phenylobacterium were greater than three log-fold more abundant in MSA+ sites as compared to MSA- sites. Further, several of these OTUs were strongly negatively correlated with pH and positively correlated with the number of wellpads in a watershed. It should be noted that many of the OTUs enriched in MSA+ sites are putative acidophilic and/or methanotrophic populations. This study revealed apparent shifts in the autochthonous microbial communities and highlighted potential members that could be responding to changing stream conditions as a result of nascent industrial activity in these aquatic ecosystems.

  17. Assessing impacts of unconventional natural gas extraction on microbial communities in headwater stream ecosystems in Northwestern Pennsylvania

    PubMed Central

    Trexler, Ryan; Solomon, Caroline; Brislawn, Colin J.; Wright, Justin R.; Rosenberger, Abigail; McClure, Erin E.; Grube, Alyssa M.; Peterson, Mark P.; Keddache, Mehdi; Mason, Olivia U.; Hazen, Terry C.; Grant, Christopher J.; Lamendella, Regina

    2014-01-01

    Hydraulic fracturing and horizontal drilling have increased dramatically in Pennsylvania Marcellus shale formations, however the potential for major environmental impacts are still incompletely understood. High-throughput sequencing of the 16S rRNA gene was performed to characterize the microbial community structure of water, sediment, bryophyte, and biofilm samples from 26 headwater stream sites in northwestern Pennsylvania with different histories of fracking activity within Marcellus shale formations. Further, we describe the relationship between microbial community structure and environmental parameters measured. Approximately 3.2 million 16S rRNA gene sequences were retrieved from a total of 58 samples. Microbial community analyses showed significant reductions in species richness as well as evenness in sites with Marcellus shale activity. Beta diversity analyses revealed distinct microbial community structure between sites with and without Marcellus shale activity. For example, operational taxonomic units (OTUs) within the Acetobacteracea, Methylocystaceae, Acidobacteriaceae, and Phenylobacterium were greater than three log-fold more abundant in MSA+ sites as compared to MSA− sites. Further, several of these OTUs were strongly negatively correlated with pH and positively correlated with the number of wellpads in a watershed. It should be noted that many of the OTUs enriched in MSA+ sites are putative acidophilic and/or methanotrophic populations. This study revealed apparent shifts in the autochthonous microbial communities and highlighted potential members that could be responding to changing stream conditions as a result of nascent industrial activity in these aquatic ecosystems. PMID:25408683

  18. Hydrological conditions regulate dissolved organic matter quality in an intermittent headwater stream. From drought to storm analysis.

    PubMed

    Guarch-Ribot, Alba; Butturini, Andrea

    2016-11-15

    Storms and droughts are an essential driver for the dissolved organic matter (DOM) concentration in headwater streams. However, the relationship between DOM quality and discharge (Q) has not been addressed in depth and the impact of other hydro-climatic or biogeochemical drivers has not been explored. In this study DOM quality variability was explored at seasonal and storm event scales during an intensive 2.5-year-long sampling in a Mediterranean stream characterized by a severe summer drought. DOM quality was described in terms of absorbance and fluorescence properties. Most of the DOM properties were strongly related to discharge revealing the input of allochthonous, degraded, aromatic, humic and increased-molecular-size DOM under high flow conditions. However, these relationships disappeared or reversed during drying and rewetting periods. Each DOM response at the storm event scale (DOM-Q hysteresis) was outlined with two descriptors that summarised its trend (dilution/flushing/chemostasis) and shape (linear/nonlinear response). Multiple linear regression and commonality analysis showed that, in addition to the magnitude of storm episodes, antecedent hydrological conditions, namely pre-event basal flow and the magnitude of the previous storm event, played a significant role in regulating the trends and shapes of DOM-Q hysteresis.

  19. Effects of upland disturbance and instream restoration on hydrodynamics and ammonium uptake in headwater streams

    USGS Publications Warehouse

    Roberts, B.J.; Mulholland, P.J.; Houser, J.N.

    2007-01-01

    Delivery of water, sediments, nutrients, and organic matter to stream ecosystems is strongly influenced by the catchment of the stream and can be altered greatly by upland soil and vegetation disturbance. At the Fort Benning Military Installation (near Columbus, Georgia), spatial variability in intensity of military training results in a wide range of intensities of upland disturbance in stream catchments. A set of 8 streams in catchments spanning this upland disturbance gradient was selected for investigation of the impact of disturbance intensity on hydrodynamics and nutrient uptake. The size of transient storage zones and rates of NH4+ uptake in all study streams were among the lowest reported in the literature. Upland disturbance did not appear to influence stream hydrodynamics strongly, but it caused significant decreases in instream nutrient uptake. In October 2003, coarse woody debris (CWD) was added to 1/2 of the study streams (spanning the disturbance gradient) in an attempt to increase hydrodynamic and structural complexity, with the goals of enhancing biotic habitat and increasing nutrient uptake rates. CWD additions had positive short-term (within 1 mo) effects on hydrodynamic complexity (water velocity decreased and transient storage zone cross-sectional area, relative size of the transient storage zone, fraction of the median travel time attributable to transient storage over a standardized length of 200 m, and the hydraulic retention factor increased) and nutrient uptake (NH4+ uptake rates increased). Our results suggest that water quality in streams with intense upland disturbances can be improved by enhancing instream biotic nutrient uptake capacity through measures such as restoring stream CWD. ?? 2007 by The North American Benthological Society.

  20. Effects of upland disturbance and instream restoration on hydrodynamics and ammonium uptake in headwater streams

    SciTech Connect

    Roberts, Brian J; Mulholland, Patrick J; Houser, Jeffrey N

    2007-01-01

    Delivery of water, sediments, nutrients, and organic matter to stream ecosystems is strongly influenced by the catchment of the stream and can be altered greatly by upland soil and vegetation disturbance. At the Fort Benning Military Installation (near Columbus, Georgia), spatial variability in intensity of military training results in a wide range of intensities of upland disturbance in stream catchments. A set of 8 streams in catchments spanning this upland disturbance gradient was selected for investigation of the impact of disturbance intensity on hydrodynamics and nutrient uptake. The size of transient storage zones and rates of NH4+ uptake in all study streams were among the lowest reported in the literature. Upland disturbance did not appear to influence stream hydrodynamics strongly, but it caused significant decreases in instream nutrient uptake. In October 2003, coarse woody debris (CWD) was added to of the study streams (spanning the disturbance gradient) in an attempt to increase hydrodynamic and structural complexity with the goals of enhancing biotic habitat and increasing nutrient uptake rates. CWD additions had positive short-term (within 1 mo) effects on hydrodynamic complexity (water velocity decreased and transient storage zone cross-sectional area, relative size of the transient storage zone, fraction of the median travel time attributable to transient storage over a standardized length of 200 m, and the hydraulic retention factor increased) and nutrient uptake (NH4+ uptake rates increased). Our results suggest that water quality in streams with intense upland disturbances can be improved by enhancing instream biotic nutrient uptake capacity through measures such as restoring stream CWD.

  1. Allochthonous input of organic matter from different riparian habitats of an agriculturally impacted stream

    NASA Astrophysics Data System (ADS)

    Delong, Michael D.; Brusven, Merlyn A.

    1994-01-01

    Lapwai Creek, an agriculturally impacted stream in northern Idaho, was examined to determine longitudinal patterns of particulate allochthonous input from different riparian vegetation types. The stream, characterized by extensive removal of mature vegetation, was classified as having four riparian vegetation types: herbaceous, herbaceous-shrub mix, shrubs, and deciduous trees. Litterfall from each vegetation type was measured monthly for two years at eight locations along Lapwai Creek using 0.1-m2 baskets. Litterfall was lowest for herbaceous habitats and highest for deciduous tree habitats. Annual litterfall was low in the headwaters, which flow through an open meadow and deep canyon, and increased from the canyon-floodplain transition downstream to the first fifth-order site. Annual litterfall decreased markedly at the last two fifth-order stream sections. Differences in annual input rates between section 6 and sections 7 and 8, all of which are fifth order, can be attributed to removal of climax riparian vegetation. Estimates of actual and potential annual allochthonous income for each site suggest that current detrital inputs to Lapwai Creek are less than could be achieved if greater quantities of climax vegetation were still present. Lower rates of allochthonous inputs to Lapwai Creek may result in a system with detrital dynamics and macroinvertebrate communities different from that of comparable undisturbed streams of this region.

  2. Impacts of Urbanization and Intermittent Flow on Macroinvertebrates in Headwater Stream

    EPA Science Inventory

    Recent Supreme Court cases have brought increased attention to the contribution of intermittent waters to the health of downstream ecosystems. However, there is still limited knowledge on what factors are shaping these frequently disturbed intermittent stream communities. The obj...

  3. Evidence of acidification of headwater streams in the new jersey pinelands.

    PubMed

    Johnson, A H

    1979-11-16

    Seventeen years of stream pH data indicate a trend of acidification in two small streams in the New Jersey Pine Barrens which drain relatively undisturbed areas. The decline in pH has amounted to approximately 0.4 unit, with an estimated increase in H(+) concentration of about 50 microequivalents per liter. The data collected to date are consistent with the postulation of an atmospheric source for the increased H(+).

  4. Ecosystem function in Appalachian headwater streams during an active invasion by the hemlock woolly adelgid.

    PubMed

    Northington, Robert M; Webster, Jackson R; Benfield, Ernest F; Cheever, Beth M; Niederlehner, Barbara R

    2013-01-01

    Forested ecosystems in the southeastern United States are currently undergoing an invasion by the hemlock woolly adelgid (HWA). Previous studies in this area have shown changes to forest structure, decreases in canopy cover, increases in organic matter, and changes to nutrient cycling on the forest floor and soil. Here, we were interested in how the effects of canopy loss and nutrient leakage from terrestrial areas would translate into functional changes in streams draining affected watersheds. We addressed these questions in HWA-infested watersheds at the Coweeta Hydrologic Laboratory in North Carolina. Specifically, we measured stream metabolism (gross primary production and ecosystem respiration) and nitrogen uptake from 2008 to 2011 in five streams across the Coweeta basin. Over the course of our study, we found no change to in-stream nutrient concentrations. While canopy cover decreased annually in these watersheds, this change in light penetration did not translate to higher rates of in-stream primary production during the summer months of our study. We found a trend towards greater heterotrophy within our watersheds, where in-stream respiration accounted for a much larger component of net ecosystem production than GPP. Additionally, increases in rhododendron cover may counteract changes in light and nutrient availability that occurred with hemlock loss. The variability in our metabolic and uptake parameters suggests an actively-infested ecosystem in transition between steady states.

  5. Influence of Pools and Riffles on Chironomidae Diversity in Headwater Streams of the Atlantic Forest.

    PubMed

    Silveira, L S; Rosa, B F J V; Gonçalves, E A; Alves, R G

    2015-10-01

    Studies on mesohabitat scale have been used to shed light on the ecology and distribution of chironomid larvae in small streams. Thus, the objective of the present study was to examine the diversity and distribution of the Chironomidae assemblage on the mesohabitat scale in three streams located in different preserved areas of southeastern Brazil. In each stream, litter samples were obtained in the dry season of 2010 in ten pools and ten riffles with a Surber sampler (area 0.04 m(2); mesh size 0.21 mm). The abundance was similar among streams and between mesohabitats, while the estimated richness was highest in riffles. There was a difference in the composition of the Chironomidae assemblages between the mesohabitats, although the litter composition was similar between them, indicating the importance of current speed on the distribution of the taxa. The dispersion of the sample units (β-diversity) of riffles and pools was similar, although it was different among the three streams. The results of this study provide further evidence of the importance of habitat heterogeneity within streams as a generator of diversity for Chironomidae in tropical lotic systems.

  6. Developing a food web-based transfer factor of radiocesium for fish, whitespotted char (Salvelinus leucomaenis) in headwater streams.

    PubMed

    Haque, Md Enamul; Gomi, Takashi; Sakai, Masaru; Negishi, Junjiro N

    2017-04-05

    We developed a food web-based transfer factor (TFweb) to study contaminant movements from multiple prey items to a predator based on the dietary contributions of prey items with their respective contamination levels. TFweb was used to evaluate the transfer of (137)Cs into whitespotted char (Salvelinus leucomaenis) from the trophic structure of a stream-riparian ecosystem in headwater streams draining a Japanese cedar forest. We also examined the applicability of this method by comparing sites with different contamination levels but similar surrounding environments in Fukushima and Gunma. All samples were collected from August 2012 to May 2013. The dietary contributions from both aquatic and terrestrial prey items to whitespotted char were analyzed using stable carbon and nitrogen isotope ratios. (137)Cs activity concentrations in char ranged from 704 to 6082 Bq kg(-1)-dry in Fukushima and from 193 to 618 Bq kg(-1)-dry in Gunma. Dominant prey taxa such as mayflies (Ephemera japonica), spider crickets (Rhaphidosphoridae gen. spp.), and freshwater crabs (Geothelphusa dehaani), each of them accounted for 3-12% of the fish diet, based on lower and upper estimates, respectively. TFweb ranged from 1.12 to 3.79 in Fukushima and from 1.30 to 4.30 in Gunma, which suggested bioaccumulation from prey items to predator. Widely used ecological parameters TFs by media-char and TTF by single prey-char showed high variability with both dilution and accumulation. TFweb is applicable for (137)Cs transfer in predator-prey systems with complex food web structures of stream-riparian ecosystems.

  7. Increasing fish taxonomic and functional richness affects ecosystem properties of small headwater prairie streams

    DOE PAGES

    Martin, Erika C.; Gido, Keith B.; Bello, Nora; ...

    2016-04-06

    Stream fish can regulate their environment through direct and indirect pathways, and the relative influence of communities with different taxonomic and functional richness on ecosystem properties likely depends on habitat structure. Given this complexity, it is not surprising that observational studies of how stream fish communities influence ecosystems have shown mixed results. In this study, we evaluated the effect of an observed gradient of taxonomic (zero, one, two or three species) and functional (zero, one or two groups) richness of fishes on several key ecosystem properties in experimental stream mesocosms. Our study simulated small (less than two metres wide) headwatermore » prairie streams with a succession of three pool-riffle structures (upstream, middle and downstream) per mesocosm. Additionally, ecosystem responses included chlorophyll a from floating algal mats and benthic algae, benthic organic matter, macroinvertebrates (all as mass per unit area), algal filament length and stream metabolism (photosynthesis and respiration rate). Ecosystem responses were analysed individually using general linear mixed models. Significant treatment (taxonomic and functional richness) by habitat (pools and riffles) interactions were found for all but one ecosystem response variable. After accounting for location (upstream, middle and downstream) effects, the presence of one or two grazers resulted in shorter mean algal filament lengths in pools compared to no-fish controls. These observations suggest grazers can maintain short algal filaments in pools, which may inhibit long filaments from reaching the surface. Accordingly, floating algal mats decreased in mid- and downstream locations in grazer treatment relative to no-fish controls. At the scale of the entire reach, gross primary productivity and respiration were greater in treatments with two grazer species compared to mixed grazer/insectivore or control treatments. Lastly, the distribution of stream resources

  8. DISSOLVED ORGANIC CARBON AND DISSOLVED CARBON DIOXIDE CONCENTRATIONS AND EXPORT IN GEORGIA PIEDMONT HEADWATER STREAMS

    EPA Science Inventory

    The South Fork Broad River (SFBR) drains about 550 km2 of the Georgia Piedmont. The SFBR watershed is primarily rural and undeveloped although the human population increased by about 25% between 1990 and 2000. Forestry and agriculture are the main land uses. Agriculture consis...

  9. Factors Controlling the Metal Levels in Headwater Stream Draining an Agroforestry Catchment (Galicia, NW Spain)

    NASA Astrophysics Data System (ADS)

    Palleiro, Laura; Rodríguez-Blanco, M. Luz; Mercedes Taboada-Castro, M.; Taboada-Castro, M. Teresa

    2016-10-01

    Concentrations of Al, Fe, Mn, Cu and Zn (dissolved and particulate), suspended sediment, dissolved organic carbon, and pH and discharge were determined during a 3-year period in a stream water of an agroforestry catchment in Galicia (NW Spain). The objective of this study is to investigate the role of these variables in the control of dissolved and particulate concentrations of each metal in the stream water. The soils in the catchment are developed on metamorphic schist. Stream water samples were collected at the catchment outlet every 15 days and more frequently with increased stream flows. Metal concentrations were measured by ICP- MS. Pearson correlation coefficients were calculated to examine the possible associations between metals and the four variables under consideration. Stepwise multiple regressions were applied to determine which predictor variables have the strongest influences on controlling concentrations of each metal in the stream. The results showed that metal concentrations were relatively low (Fe > Al > Mn > Zn > Cu), but particulate metals were predominant over those dissolved. Stepwise multiple regression analysis revealed that the most important variable to explain dissolved concentrations for Al, Fe and Cu was the dissolved organic carbon, whereas the suspended sediment was for dissolved Zn and the discharge was for dissolved Mn. The suspended sediment was also a good predictor of particulate metal levels.

  10. Occurrence of maize detritus and a transgenic insecticidal protein (Cry1Ab) within the stream network of an agricultural landscape

    PubMed Central

    Tank, Jennifer L.; Rosi-Marshall, Emma J.; Royer, Todd V.; Whiles, Matt R.; Griffiths, Natalie A.; Frauendorf, Therese C.; Treering, David J.

    2010-01-01

    Widespread planting of maize throughout the agricultural Midwest may result in detritus entering adjacent stream ecosystems, and 63% of the 2009 US maize crop was genetically modified to express insecticidal Cry proteins derived from Bacillus thuringiensis. Six months after harvest, we conducted a synoptic survey of 217 stream sites in Indiana to determine the extent of maize detritus and presence of Cry1Ab protein in the stream network. We found that 86% of stream sites contained maize leaves, cobs, husks, and/or stalks in the active stream channel. We also detected Cry1Ab protein in stream-channel maize at 13% of sites and in the water column at 23% of sites. We found that 82% of stream sites were adjacent to maize fields, and Geographical Information Systems analyses indicated that 100% of sites containing Cry1Ab-positive detritus in the active stream channel had maize planted within 500 m during the previous crop year. Maize detritus likely enters streams throughout the Corn Belt; using US Department of Agriculture land cover data, we estimate that 91% of the 256,446 km of streams/rivers in Iowa, Illinois, and Indiana are located within 500 m of a maize field. Maize detritus is common in low-gradient stream channels in northwestern Indiana, and Cry1Ab proteins persist in maize leaves and can be measured in the water column even 6 mo after harvest. Hence, maize detritus, and associated Cry1Ab proteins, are widely distributed and persistent in the headwater streams of a Corn Belt landscape. PMID:20876106

  11. Occurrence of maize detritus and a transgenic insecticidal protein (Cry1Ab) within the stream network of an agricultural landscape.

    PubMed

    Tank, Jennifer L; Rosi-Marshall, Emma J; Royer, Todd V; Whiles, Matt R; Griffiths, Natalie A; Frauendorf, Therese C; Treering, David J

    2010-10-12

    Widespread planting of maize throughout the agricultural Midwest may result in detritus entering adjacent stream ecosystems, and 63% of the 2009 US maize crop was genetically modified to express insecticidal Cry proteins derived from Bacillus thuringiensis. Six months after harvest, we conducted a synoptic survey of 217 stream sites in Indiana to determine the extent of maize detritus and presence of Cry1Ab protein in the stream network. We found that 86% of stream sites contained maize leaves, cobs, husks, and/or stalks in the active stream channel. We also detected Cry1Ab protein in stream-channel maize at 13% of sites and in the water column at 23% of sites. We found that 82% of stream sites were adjacent to maize fields, and Geographical Information Systems analyses indicated that 100% of sites containing Cry1Ab-positive detritus in the active stream channel had maize planted within 500 m during the previous crop year. Maize detritus likely enters streams throughout the Corn Belt; using US Department of Agriculture land cover data, we estimate that 91% of the 256,446 km of streams/rivers in Iowa, Illinois, and Indiana are located within 500 m of a maize field. Maize detritus is common in low-gradient stream channels in northwestern Indiana, and Cry1Ab proteins persist in maize leaves and can be measured in the water column even 6 mo after harvest. Hence, maize detritus, and associated Cry1Ab proteins, are widely distributed and persistent in the headwater streams of a Corn Belt landscape.

  12. Intra-annual variation of the association between agricultural best management practices and stream nutrient concentrations.

    PubMed

    Pearce, Nolan J T; Yates, Adam G

    2017-05-15

    Temporal variation may influence the ability of best management practices (BMPs) to mitigate the loss of agricultural pollutants to streams. Our goal was to assess variation in mitigation effects of BMPs by examining the associations between instream nutrient concentrations and the abundance and location of four structural BMPs over a hydrologic year. Water samples were collected monthly (Nov. 2013-Oct. 2014) in 15 headwater streams representing a gradient of BMP use in Southern Ontario, Canada. Partial least squares (PLS) regression models were used to associate two groups of collinear nutrient forms with the abundance and location of BMPs, antecedent precipitation and time of year. BMP metrics in PLS models were associated with instream concentrations of major phosphorus forms and ammonium throughout the year. In contrast, total nitrogen and nitrate-nitrite were only associated with BMPs during snowmelt. BMP metrics associated with reductions of phosphorus and ammonium included greater abundances of riparian buffers and manure storage structures, but not livestock restriction fences. Likewise, the abundance and location riparian vegetation in areas capturing more surface runoff were associated with decreased stream nitrogen concentrations during snowmelt. However, the amount of tile drainage was associated with increased nitrogen concentrations following snowmelt, as well as with greater phosphorus and ammonium concentrations throughout the year. Overall, our findings indicate that increasing the abundance of riparian buffers and manure storage structures may decrease instream nutrient concentrations in agricultural areas. Additionally, the implementation of these structural BMPs appear to be an effective year-round strategy to assist management objectives in reducing phosphorus concentrations in small agricultural streams and thus loadings to downstream tributaries. Further mitigation measures, such as managerial BMPs and controlled tile drainage, may be

  13. Spatial organization of stream water discharge and chemistry in forested headwaters

    NASA Astrophysics Data System (ADS)

    Egusa, T.; Ohte, N.; Oda, T.; Suzuki, M.

    2013-12-01

    It has long been known that, in small catchments, stream water discharge and chemistry are highly variable but the variability decreases gradually with an increase in the catchment area. Wood et al. (1988) showed that model calculations of infiltration and the runoff rate became constant above a certain threshold area. They defined the threshold area as the representative elementary area (REA) and stated that above the REA only minimum knowledge of the underlying parameters is needed to explain the stream water discharge and chemistry. Subsequently, empirical studies were conducted in several catchments. These studies all verified the existence of an REA in real catchments and indicated that the REA values differed among catchments. The results also suggested that the confluence processes of stream water discharge and chemistry differed among catchments. However, it has not been clarified how the confluence processes behave and why processes differ among catchments. One of the unclear things to resolve is whether the variability of discharge and chemistry among small catchments can be regarded as randomness or if it is organized. Two previous studies examined it and reported the opposite results. Woods et al. (1995) reported that organization was apparent from their observations of specific discharge. However, Asano and Uchida (2010) stated that their results for SiO2 could be regarded as randomness. These studies targeted different observed items and different catchments. Therefore, general knowledge about organization of stream water discharge and chemistry has not been obtained. We observed spatial variability of stream water discharge and chemistry and examined the existence of spatial organization by using the statistical method. Our objective was to elucidate whether the spatial organization exists about stream water discharge and chemistry. Observations were conducted in three forested catchments in Japan. Snapshot samplings of stream water discharge and

  14. Variability of DOM concentration and quality in a peatland and forest headwater stream: seasonal and event characteristics

    NASA Astrophysics Data System (ADS)

    Broder, Tanja; Knorr, Klaus-Holger; Biester, Harald

    2016-04-01

    Export of terrestrial dissolved organic matter (DOM) from soils to aquatic systems plays a fundamental role in surface water chemistry. In many catchments, main sources are peatlands and peaty riparian zones. However, not only total DOM concentration is of great interest for e.g. the carbon cycle or drinking water generation. Also the quality of DOM strongly affects function and fate of DOM in aquatic systems. Moreover, changes in DOM quality can help to elucidate sources of DOM and underlying controls of mobilization. Therefore, this study focused on changes of DOM concentration and quality in a peatland and forest headwater stream considering seasonal patterns and hydrological dynamics. The study was conducted at the Odersprung bog, in a small headwater catchment characterized by an ombrotrophic peatland with adjacent, peaty forest soils in the Harz Mountains in northwestern Germany. During a one-year campaign, sampling of the headwater stream was conducted in biweekly intervals and in high resolution during selected high discharge events. DOM was characterized by spectrofluorometric indices, such as SUVA254nm, SR, HIX and FI, as well as by PARAFAC modelling of fluorescence spectra. Results showed major changes in DOM concentration, as well as in DOM quality during the sampling period. DOM concentrations ranged between 5 to 45 mg C L-1 and were mainly controlled by season with low concentrations during snowmelt and spring and higher concentrations in late summer and fall. Highest concentrations occurred at a fall high discharge event. Compared to the peatland, the forested site with a peaty riparian zone exhibited higher DOM concentrations and a stronger variability induced by hydrologic conditions. DOM quality changes as indicated by spectrofluorometric indices and modelled PARAFAC components were mainly induced by hydrology and showed no clear seasonal pattern. An increasing water level at the bog site caused hydrological connection of fresh DOM pools and a

  15. VERTICAL, LONGITUDINAL, AND TEMPORAL VARIATION IN THE MACROBENTHOS OF AN APPALACHIAN HEADWATER STREAM SYSTEM

    EPA Science Inventory

    We examined vertical, longitudinal, and season variation in the abundance, diversity, variability, and assemblage composition of the epibenthic and hyporheic macrobenthos at Elklick Run, a first-through fourth-order stream continuum in the central Appalachian Mountains in West Vi...

  16. Do post-mining constructed channels replace functional characteristics of headwater streams?

    EPA Science Inventory

    Mountaintop mining and valley fill (MTMVF) is a method of coal mining common in eastern Kentucky and southern West Virginia. Over 1200 miles of stream channel have been buried by MTMVF. Permits for surface coal mining have recognized constructed drainage ditches associated with ...

  17. Controls on stream water dissolved mercury in three mid-Appalachian forested headwater catchments

    NASA Astrophysics Data System (ADS)

    Riscassi, Ami L.; Scanlon, Todd M.

    2011-12-01

    Determining the controls on dissolved mercury (HgD) transport is necessary to improve estimations of export from unmonitored watersheds and to forecast responses to changes in deposition and other environmental forcings. Stream water HgD and dissolved organic carbon (DOC) were evaluated over a range of discharge conditions in three streams within Shenandoah National Park, VA. Watersheds are distinguished by stream water pH (ranging from neutral to acidic) and soil size fractioning (ranging from clays to sands). At all sites, discharge was a significant but poor predictor of HgD concentrations (r2 from 0.13-0.52). HgD was strongly coupled with DOC at all sites (r2 from 0.74-0.89). UV absorbance at 254 nm (UV254), a proxy for DOC quantity and quality, slightly improved the predictions of HgD. Mean DOC quality differed between streams, with less aromatic DOC mobilized from the more acidic watershed. The site with less aromatic DOC and sandy soils mobilized more Hg to the stream for the same quantity and quality of DOC, likely due to the reduced capacity of the larger-grained soils to retain Hg, leaving a greater fraction associated with the organic matter. A similar amount of 0.54 ng HgD/mg DOC is transported at all sites, suggesting the less aromatic DOC transports less Hg per unit DOC, offsetting the effects of soil type. This research demonstrates that soil composition and DOC quality influence HgDexport. We also provide evidence that soil organic carbon is a primary control on Hg-DOC ratios (0.12-1.4 ng mg-1) observed across the U.S. and Sweden.

  18. Potential population and assemblage influences of non-native trout on native nongame fish in Nebraska headwater streams

    USGS Publications Warehouse

    Turek, Kelly C.; Pegg, Mark A.; Pope, Kevin L.; Schainost, Steve

    2014-01-01

    Non-native trout are currently stocked to support recreational fisheries in headwater streams throughout Nebraska. The influence of non-native trout introductions on native fish populations and their role in structuring fish assemblages in these systems is unknown. The objectives of this study were to determine (i) if the size structure or relative abundance of native fish differs in the presence and absence of non-native trout, (ii) if native fish-assemblage structure differs in the presence and absence of non-native trout and (iii) if native fish-assemblage structure differs across a gradient in abundances of non-native trout. Longnose dace Rhinichthys cataractae were larger in the presence of brown trout Salmo trutta and smaller in the presence of rainbow trout Oncorhynchus mykiss compared to sites without trout. There was also a greater proportion of larger white suckers Catostomus commersonii in the presence of brown trout. Creek chub Semotilus atromaculatus and fathead minnow Pimephales promelas size structures were similar in the presence and absence of trout. Relative abundances of longnose dace, white sucker, creek chub and fathead minnow were similar in the presence and absence of trout, but there was greater distinction in native fish-assemblage structure between sites with trout compared to sites without trout as trout abundances increased. These results suggest increased risk to native fish assemblages in sites with high abundances of trout. However, more research is needed to determine the role of non-native trout in structuring native fish assemblages in streams, and the mechanisms through which introduced trout may influence native fish populations.

  19. Channel morphology and patterns of bedload transport in fluvial, formerly-glaciated, forested headwater streams of the Columbia Mountains, Canada

    NASA Astrophysics Data System (ADS)

    Green, Kim; Brardinoni, Francesco; Alila, Younes

    2013-04-01

    This study examines channel-reach morphology and bedload transport dynamics in relation to landscape structure and snowmelt hydrology in Cotton and Elk Creek, two headwater streams of the southern Columbia Mountains, Canada. Data collection is based on field surveys and GIS analysis in conjunction with a nested monitoring network of water discharge and bed load transfer. The nested monitoring network is designed to examine the effects of channel bed texture, and the influence of free-formed (i.e., boulder cascades, step pools, and riffle pools) and forced-alluvial morphologies (i.e., forced step pools) on bedload entrainment and transport. The landscape is characterized by subdued glaciated topography in which sediment is primarily supplied by bank failures and fluvial transfer dominates the channelized sediment cascade. The spatial distribution of channel types is mainly controlled by glacially imposed local slope together with availability of wood and glacigenic materials. Interestingly, downstream hydraulic geometry as well as downstream patterns of the coarse channel bed fraction and stream power are all insensitive to systematic changes of local slope along the typically stepped longitudinal profiles. An indication that the study alluvial systems are adjusted to the contemporary hydrologic and sedimentary regimes, and as such through post-LGM times have been able to compensate for the glacially-imposed boundary conditions. Stepwise multiple regression indicates that annual bedload yield is chiefly controlled by the number of peak events over threshold discharge. During such high flows, repeated destabilization of channel bed armouring and re-mobilization of sediment stored behind logjams can ensure sediment supply for bedload transport across the entire snowmelt season. In particular, channel morphology affects distinctively the variability of bed load response to hydrologic forcing. The observed spatial variability in annual bedload yield appears to correlate

  20. Spatio-temporal variability of the molecular fingerprint of soil dissolved organic matter in a headwater agricultural catchment

    NASA Astrophysics Data System (ADS)

    Jeanneau, Laurent; Pierson-Wickmann, Anne-Catherine; Jaffrezic, Anne; Lambert, Thibault; Gruau, Gérard

    2013-04-01

    Dissolved organic matter (DOM) is implied in (i) ecosystem services such as the support of biodiversity, (ii) the alteration of the drinkable water quality by formation of trihalomethane and (iii) the transfer of micropollutants from soils to rivers. Moreover, since DOM connects soils and oceans that are interacting with the atmosphere, understanding its biogeochemistry will help in investigating the carbon cycle and in creating strategies to mitigate climate change. DOM in headwater stream ecosystems is mainly inherited from allochtonous inputs with different reservoirs being mobilized during storm and interstorm events at the scale of an hydrological year. Those changes in DOM reservoirs, if accompanied by composition and reactivity changes, may impact DOM ecosystem services and drinking water production processes. Elucidating the compositional changes due to changes in the source of DOM in rivers has thus become a important axis of DOM research. The aim of this study is to test the ability of the molecular tools of the organic geochemistry and more specifically the combination of thermochemiolysis and gas chromatography - mass spectrometry (THM-GC-MS) to (i) link the variability of the river DOM composition to different DOM reservoirs in catchment soils and (ii) provide hypothesis on the nature and the mechanisms of formation (microbial growth, litter decomposition) of those reservoirs. This analytical method seems particularly adapted since it allows the differentiation between vegetal and microbial inputs and the determination of the extent of the biodegradation process of biomolecules such as lignin. To test this method, the molecular fingerprint of soil DOM has been investigated in the wetland area of a small (500 ha) agricultural catchment (the so-called Kervidy-Naizin catchment) located in Brittany, western France. The soil DOM was sampled fortnightly at three depths using zero-tension lysimeters during the hydrological year 2010-2011. The samples were

  1. DOC:NO3- ratios and NO3- uptake in forested headwater streams

    NASA Astrophysics Data System (ADS)

    Rodríguez-Cardona, Bianca; Wymore, Adam S.; McDowell, William H.

    2016-01-01

    The underlying mechanisms driving the coupled interactions between inorganic nitrogen uptake and dissolved organic matter are not well understood, particularly in surface waters. To determine the relationship between dissolved organic carbon (DOC) quantity and nitrate (NO3-) uptake kinetics in streams, we performed a series of NO3- Tracer Additions for Spiraling Curve Characterization experiments in four streams within the Lamprey River Watershed, New Hampshire, across a range in background DOC concentrations (1-8 mg C/L). Experiments were performed throughout the 2013 and 2014 growing seasons. Across streams and experimental dates, ambient uptake velocity (Vf) correlated positively with increasing DOC concentrations and DOC:NO3- ratios but was only weakly negatively associated with NO3- concentrations. Ambient NO3- Vf was unrelated to pH, light, temperature, dissolved oxygen, and Specific Ultraviolet Absorbance at 254 nm. Although there were general tendencies across the entire Lamprey River Watershed, individual sites behaved differently in their uptake kinetics. NO3- uptake dynamics in the Lamprey River Watershed are most strongly influenced by DOC concentrations rather than NO3- concentrations or physicochemical parameters, which have been identified as regional- to continental-scale drivers in previous research. Understanding the fundamental relationships between dissolved organic matter and inorganic nutrients will be important as global and climatic changes influence the delivery and production of DOC and NO3- in aquatic ecosystems.

  2. Fish abundance and population stability in a reservoir tailwater and an unregulated headwater stream

    USGS Publications Warehouse

    Jacobs, K.E.; Swink, W.D.

    1983-01-01

    Fish abundance and population stability were compared in the tailwater and in an unregulated tributary of Barren River Lake, a flood control reservoir in south central Kentucky. Fish abundance was greater in the tailwater near the dam and was dominated by three species common in the reservoir: gizzard shad (Dorosoma cepedianum), bluegills (Lepomis macrochirus), and white crappies (Pomoxis annularis). Three riverine suckers were less abundant in the tailwater than in the unregulated stream: northern hog suckers (Hypentelium nigricans), black redhorse (Moxostoma duquesnei), and golden redhorse (Moxostoma erythrurum). The fish populations in the tailwater, particularly common carp (Cyprinus carpio), northern hog suckers, black redhorse, and golden redhorse, were less stable than those in the unregulated stream. Population stability is defined as the extent to which fish remain in a stream section. This study suggests that the occurrence of reservoir species in the tailwater was the result of fish passage from the reservoir during high discharges in fall and winter. Reservoir operations (altered flow, low summer water temperature, and poor summer water quality) probably were responsible for the unstable populations of common carp and riverine suckers in the tailwater.

  3. Dominance of organic nitrogen from headwater streams to large rivers across the conterminous United States

    USGS Publications Warehouse

    Scott, D.; Harvey, J.; Alexander, R.; Schwarz, G.

    2007-01-01

    The frequency and magnitude of hypoxic areas in coastal waterbodies are increasing across the globe, partially in response to the increase in nitrogen delivery from the landscape (Diaz, 2001; Rabalais et al., 2002). Although studies of annual total nitrogen and nitrate yields have greatly improved understanding of the contaminant sources that contribute to riverine nitrogen loads (Alexander et al., 2000; Caraco and Cole, 1999), the emphasis of these studies on annual timescales and selected nitrogen forms is not sufficient to understand the factors that control the cycling, transport, and fate of reactive nitrogen. Here we use data from 850 river stations to calculate long-term mean-annual and interannual loads of organic, ammonia, and nitrate-nitrite nitrogen suitable for spatial analysis. We find that organic nitrogen is the dominant nitrogen pool within rivers across most of the United States and is significant even in basins with high anthropogenic sources of nitrogen. Downstream organic nitrogen patterns illustrate that organic nitrogen is an abundant fraction of the nitrogen loads in all regions. Although the longitudinal patterns are not consistent across regions, these patterns are suggestive of cycling between ON and NO3- on seasonal timescales influenced by land use, stream morphology, and riparian connectivity with active floodplains. Future regional studies need to incorporate multinitrogen species at intraannual timescales, as well as stream characteristics beyond channel depth, to elucidate the roles of nitrogen sources and in-stream transformations on the fate and reactivity of riverine nitrogen transported to coastal seas.

  4. Freshwater transport forms of Na, Mg, and Ca in streams of adjacent headwater catchments composed of differing vegetation

    NASA Astrophysics Data System (ADS)

    Terajima, T.; Moriizumi, M.

    2012-04-01

    To understand the freshwater transport forms of major metals, concentrations of Na, Mg, Ca, Si, and fulvic acid-like materials (FAM) were measured in streams of headwater catchments with differing vegetation (coniferous and deciduous forests). The proportion of non-ionic forms (NIF) relative to total elements in the coniferous and deciduous catchments ranged from 0% to 40% and from 0% to 70%, respectively, in baseflows, and from 5% to 60% and from 20% to 60%, respectively, in stormflows. In the baseflows, NIF and total Si (T-Si) were highly correlated (r > 0.9) in both catchments. In contrast, in the stormflows, T-Si and FAM showed a good correlation (r > 0.8) in both catchments, implying that stormflow may have enhanced organic-inorganic binding. However, in the coniferous catchment, good correlations (r > 0.8) between NIF and T-Si or FAM were associated with only the rising limb of the hydrograph, whereas in the deciduous catchment, good correlations (r > 0.8) were associated with both the rising and falling limbs. These results indicate that: (1) under low-flow conditions, major metals may form binding with clay minerals and thus be transported as NIF, (2) storm events may enhance the binding of clay minerals with humic substances, (3) in the coniferous catchment, the complexation of NIF with the organic-inorganic binding and their transport in stormflows are associated with the rising limb of the storm hydrograph, whereas NIF transport during the falling limb may reflect the effect of other materials, and (4) in the deciduous catchment, NIF transport may occur mainly in association with organic-inorganic binding throughout a storm event. These findings show that active binding of Na, Mg, and Ca in freshwater environments with organic and inorganic substances, under the effect of differing vegetation on that binding, should be carefully examined in studies of chemical hydrology in headwater catchments. Key words: fulvic acid, major metal, complexation, humic

  5. Natural organic matter properties in Swedish agricultural streams

    NASA Astrophysics Data System (ADS)

    Bieroza, Magdalena; Kyllmar, Katarina; Bergström, Lars; Köhler, Stephan

    2016-04-01

    We have analysed natural organic matter (NOM) properties in 18 agricultural streams in Sweden covering a broad range of environmental (climate, soil type), land use and water quality (nutrient and concentrations, pH, alkalinity) characteristics. Stream water samples collected every two weeks within an ongoing Swedish Monitoring Programme for Agriculture have been analysed for total/dissolved organic carbon, absorbance and fluorescence spectroscopy. A number of quantitative and qualitative spectroscopic parameters was calculated to help to distinguish between terrestrially-derived, refractory organic material and autochthonous, labile material indicative of biogeochemical transformations of terrestrial NOM and recent biological production. The study provides insights into organic matter properties and carbon budgets in agricultural streams and improves understanding of how agricultural catchments transform natural and anthropogenic fluxes of organic matter and nutrients to signals observed in receiving waters.

  6. Sediment transport dynamics and its relation to primary production in mountain headwater streams

    NASA Astrophysics Data System (ADS)

    Katz, S.; Segura, C.; Warren, D.

    2015-12-01

    This study explores how the spatial and temporal variability of stream flow and sediment transport influence the growth and recovery rate of benthic primary producers in a rainfall dominated mountain stream over different seasons. Primary producers sustain higher trophic levels and thus understanding how sediment transport impacts their growth is important for efficient river management. The control of sediment transport processes on suitable habitat for these organisms depends on the frequency of high flows capable of mobilizing material and the spatial distribution of forces throughout the stream. However there other factors such as light, nutrient availability, and temperature that are also important. We hypothesize that the control physical processes exert on the growth dynamics of these organisms varies both according to the amount of localized bed disturbance caused by sediment transport and the flow field and seasonal variations in additional growth factors. This hypothesis is tested in a 160m reach of Oak Creek, OR draining 7 km2. Habitat disturbance maps were developed based on the spatial and temporal variability of velocity and shear stress and estimated sediment transport rates. These maps are used to select habitat patches with contrasting disturbance levels for benthic chlorophyll a monitoring. Velocity and shear stress were modeled using the two dimensional hydraulic model FaSTMECH, developed by the USGS. Sediment transport rates were estimated using spatially variable magnitudes of shear stress and grain size distributions and validated using both field measurements and historical data. Preliminary results during the spring indicate an inverse correlation between disturbance and algal growth, however there were no flow events above the critical threshold for motion during this time. It is likely that increased nutrient fluxes in areas of higher velocity resulted in increased algal growth rates during these period.

  7. The "Flushing" of Dissolved Organic Carbon from Hillslope Soils to a Headwater Stream

    NASA Astrophysics Data System (ADS)

    Mei, Y.; Hornberger, G.; Kaplan, L. A.; Aufdenkampe, A. K.; Newbold, J. D.

    2012-12-01

    Event export of dissolved organic carbon (DOC) from terrestrial sources to streams was found to account for a significant portion of annual export of DOC. Thus, determining the first-order control on DOC export is of great importance in terms of carbon cycling and budget. In this work, the well-known DOC "flushing hypothesis" was tested mechanically using field data and a physically-based model in a combined approach. Field hydrological data collection and DOC sampling were conducted within the White Clay Creek (WCC) watershed in southeastern Pennsylvania in 2010. A two dimensional saturated-unsaturated finite element model was then developed to describe the soil and groundwater flow, DOC, BDOC responses to the precipitation events. The flow and reactive transport models was calibrated in sequence after the model was built. Simulation results showed that the calibrated model can reproduce the pattern of the stream DOC variation during the storm for three precipitation events from July12, 2010 to July19, 2010, and give a reasonable understanding of field DOC data. The model captured the details of the process put forth in the "flushing hypothesis": DOC was leached from near-surface layers by a rising water table followed by a quick lateral transport of these leached nutrients to the stream via near-surface. A rapid decline of DOC flux in the saturated zone was found from the selected vertical cross section of the model from riparian zone to up hillslope. This is consistent with our previous study that indicated a significant role for the riparian zone in DOC export.

  8. Hydrological control of organic carbon support for bacterial growth in boreal headwater streams.

    PubMed

    Berggren, Martin; Laudon, Hjalmar; Jansson, Mats

    2009-01-01

    Terrestrial organic carbon is exported to freshwater systems where it serves as substrate for bacterial growth. Temporal variations in the terrigenous organic carbon support for aquatic bacteria are not well understood. In this paper, we demonstrate how the combined influence of landscape characteristics and hydrology can shape such variations. Using a 13-day bioassay approach, the production and respiration of bacteria were measured in water samples from six small Swedish streams (64 degrees N, 19 degrees E), draining coniferous forests, peat mires, and mixed catchments with typical boreal proportions between forest and mire coverage. Forest drainage supported higher bacterial production and higher bacterial growth efficiency than drainage from mires. The areal export of organic carbon was several times higher from mire than from forest at low runoff, while there was no difference at high flow. As a consequence, mixed streams (catchments including both mire and forest) were dominated by mire organic carbon with low support of bacterial production at low discharge situations but dominated by forest carbon supporting higher bacterial production at high flow. The stimulation of bacterial growth during high-flow episodes was a result of higher relative export of organic carbon via forest drainage rather than increased drainage of specific "high-quality" carbon pools in mire or forest soils.

  9. Land Use Influences Niche Size and the Assimilation of Resources by Benthic Macroinvertebrates in Tropical Headwater Streams

    PubMed Central

    Parreira de Castro, Diego Marcel; Reis de Carvalho, Débora; Pompeu, Paulo dos Santos; Moreira, Marcelo Zacharias; Nardoto, Gabriela Bielefeld; Callisto, Marcos

    2016-01-01

    It is well recognized that assemblage structure of stream macroinvertebrates changes with alterations in catchment or local land use. Our objective was to understand how the trophic ecology of benthic macroinvertebrate assemblages responds to land use changes in tropical streams. We used the isotope methodology to assess how energy flow and trophic relations among macroinvertebrates were affected in environments affected by different land uses (natural cover, pasture, sugar cane plantation). Macroinvertebrates were sampled and categorized into functional feeding groups, and available trophic resources were sampled and evaluated for the isotopic composition of 13C and 15N along streams located in the Cerrado (neotropical savanna). Streams altered by pasture or sugar cane had wider and more overlapped trophic niches, which corresponded to more generalist feeding habits. In contrast, trophic groups in streams with native vegetation had narrower trophic niches with smaller overlaps, suggesting greater specialization. Pasture sites had greater ranges of resources exploited, indicating higher trophic diversity than sites with natural cover and sugar cane plantation. We conclude that agricultural land uses appears to alter the food base and shift macroinvertebrate assemblages towards more generalist feeding behaviors and greater overlap of the trophic niches. PMID:26934113

  10. Land Use Influences Niche Size and the Assimilation of Resources by Benthic Macroinvertebrates in Tropical Headwater Streams.

    PubMed

    Parreira de Castro, Diego Marcel; Reis de Carvalho, Débora; Pompeu, Paulo dos Santos; Moreira, Marcelo Zacharias; Nardoto, Gabriela Bielefeld; Callisto, Marcos

    2016-01-01

    It is well recognized that assemblage structure of stream macroinvertebrates changes with alterations in catchment or local land use. Our objective was to understand how the trophic ecology of benthic macroinvertebrate assemblages responds to land use changes in tropical streams. We used the isotope methodology to assess how energy flow and trophic relations among macroinvertebrates were affected in environments affected by different land uses (natural cover, pasture, sugar cane plantation). Macroinvertebrates were sampled and categorized into functional feeding groups, and available trophic resources were sampled and evaluated for the isotopic composition of 13C and 15N along streams located in the Cerrado (neotropical savanna). Streams altered by pasture or sugar cane had wider and more overlapped trophic niches, which corresponded to more generalist feeding habits. In contrast, trophic groups in streams with native vegetation had narrower trophic niches with smaller overlaps, suggesting greater specialization. Pasture sites had greater ranges of resources exploited, indicating higher trophic diversity than sites with natural cover and sugar cane plantation. We conclude that agricultural land uses appears to alter the food base and shift macroinvertebrate assemblages towards more generalist feeding behaviors and greater overlap of the trophic niches.

  11. Characterization of major-ion chemistry and nutrients in headwater streams along the Appalachian National Scenic Trail and within adjacent watersheds, Maine to Georgia

    USGS Publications Warehouse

    Argue, Denise M.; Pope, Jason P.; Dieffenbach, Fred

    2012-01-01

    An inventory of water-quality data on field parameters, major ions, and nutrients provided a summary of water quality in headwater (first- and second-order) streams within watersheds along the Appalachian National Scenic Trail (Appalachian Trail). Data from 1,817 sampling sites in 831 catchments were used for the water-quality summary. Catchment delineations from NHDPlus were used as the fundamental geographic units for this project. Criteria used to evaluate sampling sites for inclusion were based on selected physical attributes of the catchments adjacent to the Appalachian Trail, including stream elevation, percentage of developed land cover, and percentage of agricultural land cover. The headwater streams of the Appalachian Trail are generally dilute waters, with low pH, low acid neutralizing capacity (ANC), and low concentrations of nutrients. The median pH value was slightly acidic at 6.7; the median specific conductance value was 23.6 microsiemens per centimeter, and the median ANC value was 98.7 milliequivalents per liter (μeq/L). Median concentrations of cations (calcium, magnesium, sodium, and potassium) were each less than 1.5 milligrams per liter (mg/L), and median concentrations of anions (bicarbonate, chloride, fluoride, sulfate, and nitrate) were less than 10 mg/L. Differences in water-quality constituent levels along the Appalachian Trail may be related to elevation, atmospheric deposition, geology, and land cover. Spatial variations were summarized by ecological sections (ecosections) developed by the U.S. Forest Service. Specific conductance, pH, ANC, and concentrations of major ions (calcium, chloride, magnesium, sodium, and sulfate) were all negatively correlated with elevation. The highest elevation ecosections (White Mountains, Blue Ridge Mountains, and Allegheny Mountains) had the lowest pH, ANC, and concentrations of major ions. The lowest elevation ecosections (Lower New England and Hudson Valley) generally had the highest pH, ANC, and

  12. Redox dynamics in the active layer of an Arctic headwater catchment; examining the potential for transfer of dissolved methane from soils to stream water

    NASA Astrophysics Data System (ADS)

    Street, Lorna E.; Dean, Joshua F.; Billett, Michael F.; Baxter, Robert; Dinsmore, Kerry J.; Lessels, Jason S.; Subke, Jens-Arne; Tetzlaff, Doerthe; Wookey, Philip A.

    2016-11-01

    The linkages between methane production, transport, and release from terrestrial and aquatic systems are not well understood, complicating the task of predicting methane emissions. We present novel data examining the potential for the saturated zone of active layer soils to act as a source of dissolved methane to the aquatic system, via soil water discharge, within a headwater catchment of the continuous permafrost zone in Northern Canada. We monitored redox conditions and soil methane concentrations across a transect of soil profiles from midstream to hillslope and compare temporal patterns in methane concentrations in soils to those in the stream. We show that redox conditions in active layer soils become more negative as the thaw season progresses, providing conditions suitable for net methanogenesis and that redox conditions are sensitive to increased precipitation during a storm event—but only in shallower surface soil layers. While we demonstrate that methane concentrations at depth in the hillslope soils increase over the course of the growing season as reducing conditions develop, we find no evidence that this has an influence on stream water methane concentrations. Sediments directly beneath the stream bed, however, remain strongly reducing at depth throughout the thaw season and contain methane at concentrations 5 orders of magnitude greater than those in hillslope soils. The extent of substreambed methane sources, and the rates of methane transport from these zones, may therefore be important factors determining headwater stream methane concentrations under changing Arctic hydrologic regimes.

  13. Benthic algae stimulate leaf litter decomposition in detritus-based headwater streams: a case of aquatic priming effect?

    PubMed

    Danger, Michael; Cornut, Julien; Chauvet, Eric; Chavez, Paola; Elger, Arnaud; Lecerf, Antoine

    2013-07-01

    In detritus-based ecosystems, autochthonous primary production contributes very little to the detritus pool. Yet primary producers may still influence the functioning of these ecosystems through complex interactions with decomposers and detritivores. Recent studies have suggested that, in aquatic systems, small amounts of labile carbon (C) (e.g., producer exudates), could increase the mineralization of more recalcitrant organic-matter pools (e.g., leaf litter). This process, called priming effect, should be exacerbated under low-nutrient conditions and may alter the nature of interactions among microbial groups, from competition under low-nutrient conditions to indirect mutualism under high-nutrient conditions. Theoretical models further predict that primary producers may be competitively excluded when allochthonous C sources enter an ecosystem. In this study, the effects of a benthic diatom on aquatic hyphomycetes, bacteria, and leaf litter decomposition were investigated under two nutrient levels in a factorial microcosm experiment simulating detritus-based, headwater stream ecosystems. Contrary to theoretical expectations, diatoms and decomposers were able to coexist under both nutrient conditions. Under low-nutrient conditions, diatoms increased leaf litter decomposition rate by 20% compared to treatments where they were absent. No effect was observed under high-nutrient conditions. The increase in leaf litter mineralization rate induced a positive feedback on diatom densities. We attribute these results to the priming effect of labile C exudates from primary producers. The presence of diatoms in combination with fungal decomposers also promoted decomposer diversity and, under low-nutrient conditions, led to a significant decrease in leaf litter C:P ratio that could improve secondary production. Results from our microcosm experiment suggest new mechanisms by which primary producers may influence organic matter dynamics even in ecosystems where autochthonous

  14. Measurement of Channel Morphology in a Headwater Stream using Low-Altitude Photography and a 3D Model Software

    NASA Astrophysics Data System (ADS)

    Nidaira, K.; Hiraoka, M.; Gomi, T.; Uchiyama, Y.

    2015-12-01

    We developed a method for measuring detail channel morphology using a low elevation photographic scanning. This study was conducted in a 36-m step-pool channel segment in a headwater stream of Ooborazawa watershed located in 20 km south of Tokyo. The channels were covered by Boenninghausenia japonica and Oplismenus undulatifolius var. undulatifolius. Therefore, topographic measurement in high altitude (up to 5 m) using a drone is not applicable. D50 and D90 of channel substrates were 4 cm and 21 cm, respectively. A plastic case that equipped with two digital cameras (RICOH CX5) is mounted at the top of 2.2 m of a glass fiber pole. Photos were taken every 5 seconds from 1.8 m above ground surface. Eleven ground control points (GCP) were installed and measured coordinates. We developed digital 3D topographic model using PhotoScan Pro edition version 1.0.0 and the developed 1 cm contour map using ArcGIS version 10.2. Furthermore, we measured the number, height, and length of steps for examining the accuracy of data. Resolution of obtained topographic model was from 9 to 11 mm per pixel. 1 cm of particle was identified using photo was 1 cm. Estimated step height was agreed to the measured step height in the field. We detected maximum channel scour from October to December, 2014 with (146.5 mm/day for maximum daily rain) occurred at pools with 13cm changes , while 5 to 10 cm of changes in sediment deposition occurred from Mya to June, 2015 with 78.5 mm/day of maximum daily rain. Disposition of sediment was concentration within the sequences of step structures. Our method allows us for understanding detail sediment movement and resultant localized channel changes in steep channels.

  15. Leaf litter processing and invertebrate assemblages along a pollution gradient in a Maine (USA) headwater stream.

    PubMed

    Woodcock, Thomas S; Huryn, Alexander D

    2005-04-01

    During the autumn of 1997 and 1998, leaf litter processing rates and leaf pack invertebrate assemblages were examined at eight stations along a pollution gradient in Goosefare Brook, a first-order coastal plain stream in southern Maine (USA). There was no significant effect on litter softening rate in 1997, and only the most polluted station showed a decrease in 1998. However, litter loss rates showed decreases in both years. The structure of invertebrate assemblages changed in response to the stresses, showing a decline in EPT richness and an increase in the proportion of collecting taxa. However, total shredder biomass was only weakly affected. Shredder biomass at all stations was dominated by Tipula, and biomass of other shredder taxa showed a serial replacement along the gradient of stress related to their pollution tolerance. Rather than the expected relationship with shredder biomass, litter processing rates were directly related to water and sediment quality. Goosefare Brook demonstrates how variable pollution tolerance of community members enables stress resistance and a consequent preservation of ecosystem function.

  16. The Contribution of Individual Springs to the Chemistry of a Headwater Stream in the Colorado Rockies

    NASA Astrophysics Data System (ADS)

    Rhoades, C.; Dwire, K.; Quiet, N.; Dixon, M.

    2006-12-01

    Here we examine spatial patterns in dissolved oxygen, temperature and inorganic and organic chemistry of water emerging from fifty springs in a high-elevation watershed at the Fraser Experimental Forest, Colorado. The springs extend from above treeline at 3500m to 3000m within subalpine forest. Conductivity, pH and ANC of spring water average 42 μS cm -1, 7.0, and 360 μeq L-1, respectively. In general, spring water was less chemically dilute than streamwater though spring chemistry differed with elevation and proximity to the stream channel. Concentrations of most dissolved inorganic ions were lowest in springs near treeline, and both spring water and streamwater chemical concentrations increased at lower elevation. Spring water contained higher concentrations of sodium, potassium, chloride and sulfate than streamwater. Nitrate was also higher, but DOC was lower and DON did not differ compared to streamwater. In general, spring water was well oxygenated, and DO was highest in the coldest and most vigorously flowing springs. Spring water remained 3°C cooler than streamwater during summer months. The more dilute chemical composition of the treeline springs suggests that they are fed by recent snowmelt. In contrast, springs with the highest ion concentrations emerge from faulted portions of the watershed where groundwater may follow deeper flowpaths and contact weatherable materials. The chemical composition of streamwater was most similar to spring water emerging near the channel. The high discharge and their relative abundance suggests that these springs may have a predominant influence on basin-scale aqueous chemistry.

  17. Ecology and management of agricultural drainage ditches: a literature review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural drainage ditches are headwater streams that have been modified or constructed for agricultural drainage, and are often used in conjunction with tile drains. These modified streams are a common landscape feature in Ohio, and constitute 25% of stream habitat within the state. Management o...

  18. Physical, chemical, and biological characteristics of selected headwater streams along the Allegheny Front, Blair County, Pennsylvania, July 2011–September 2013

    USGS Publications Warehouse

    Low, Dennis J.; Brightbill, Robin A.; Eggleston, Heather L.; Chaplin, Jeffrey J.

    2016-02-29

    Biotic health was characterized at 10 of 12 stream sites; the two sites excluded were established late in the study period (May 2013) for refinement of water quality in the headwaters of Poplar Run and the location of Marcellus Formation gas wells. On the basis of the Maryland Index of Biotic Integrity (MdIBI) for fish assemblages, 8 of 10 streams can be considered in fair health. Tipton Run had the highest MdIBI score (3.75) and the greatest number of native species. South Poplar Run had the lowest MdIBI score (1.75); pollution tolerant blacknose dace was dominant. On the basis of the Pennsylvania Department of Environmental Protection macroinvertebrate index of biotic integrity, 9 of 10 streams were characterized as attaining, with scores as high as 88.9 at Tipton Run. Only Sugar Run was characterized as impaired, with a score of 40.4.

  19. Impact of agricultural activities on anaerobic processes in stream sediments

    NASA Astrophysics Data System (ADS)

    Schade, J. D.; Ludwig, S.; Nelson, L. C.; Porterfield, J.; Sather, K. L.; Songpitak, M.; Spawn, S.; Weigel, B.

    2013-12-01

    Streams draining agriculture watersheds are subject to significant anthropogenic impacts, including sedimentation from soil erosion and high nitrate input from heavy fertilizer application. Sedimentation degrades habitat and can reduce hydrologic exchange between surface and subsurface waters. Disconnecting surface and subsurface flow reduces oxygen input to hyporheic water, increasing the extent of anoxic zones in stream sediments and creating hotspots for anaerobic processes like denitrification and methanogenesis that can be important sources of nitrous oxide and methane, both powerful greenhouse gases. Increased nitrate input may influence greenhouse gas fluxes from stream sediments by stimulating rates of denitrification and potentially reducing rates of methanogenesis, either through direct inhibition or by increasing competition for organic substrates from denitrifying bacteria. We hypothesized that accumulation of fine sediments in stream channels would result in high rates of methanogenesis in stream sediments, and that increased nitrate input from agricultural runoff would stimulate denitrification and reduce rates of methane production. Our work focused on streams in northern and central Minnesota, in particular on Rice Creek, a small stream draining an agricultural watershed. We used a variety of approaches to test our hypotheses, including surveys of methane concentrations in surface waters of streams ranging in sediment type and nitrate concentration, bottle incubations of sediment from several sites in Rice Creek, and the use of functional gene probes and RNA analyses to determine if genes for these processes are present and being expressed in stream sediments. We found higher methane concentrations in surface water from streams with large deposits of fine sediments, but significantly less methane in these streams when nitrate concentrations were high. We also found high potential for both methanogenesis and denitrification in sediment incubations

  20. Fish community dynamics following dam removal in a fragmented agricultural stream

    USGS Publications Warehouse

    Kornis, Matthew; Weidel, Brian C.; Powers, Stephens; Diebel, Matthew W.; Cline, Timpthy; Fox, Justin; Kitchell, James F.

    2014-01-01

    Habitat fragmentation impedes dispersal of aquatic fauna, and barrier removal is increasingly used to increase stream network connectivity and facilitate fish dispersal. Improved understanding of fish community response to barrier removal is needed, especially in fragmented agricultural streams where numerous antiquated dams are likely destined for removal. We examined post-removal responses in two distinct fish communities formerly separated by a small aging mill dam. The dam was removed midway through the 6 year study, enabling passage for downstream fishes affiliated with a connected reservoir into previously inaccessible habitat, thus creating the potential for taxonomic homogenization between upstream and downstream communities. Both communities changed substantially post-removal. Two previously excluded species (white sucker, yellow perch) established substantial populations upstream of the former dam, contributing to a doubling of total fish biomass. Meanwhile, numerical density of pre-existing upstream fishes declined. Downstream, largemouth bass density was inversely correlated with prey fish density throughout the study, while post-removal declines in bluegill density coincided with cooler water temperature and increased suspended and benthic fine sediment. Upstream and downstream fish communities became more similar post-removal, represented by a shift in Bray-Curtis index from 14 to 41 % similarity. Our findings emphasize that barrier removal in highly fragmented stream networks can facilitate the unintended and possibly undesirable spread of species into headwater streams, including dispersal of species from remaining reservoirs. We suggest that knowledge of dispersal patterns for key piscivore and competitor species in both the target system and neighboring systems may help predict community outcomes following barrier removal.

  1. Water quality status and trends in agriculture-dominated headwaters; a national monitoring network for assessing the effectiveness of national and European manure legislation in The Netherlands.

    PubMed

    Rozemeijer, J C; Klein, J; Broers, H P; van Tol-Leenders, T P; van der Grift, B

    2014-12-01

    Large nutrient losses to groundwater and surface waters are a major drawback of the highly productive agricultural sector in The Netherlands. The resulting high nutrient concentrations in water resources threaten their ecological, industrial, and recreational functions. To mitigate eutrophication problems, legislation on nutrient application in agriculture was enforced in 1986 in The Netherlands. The objective of this study was to evaluate this manure policy by assessing the water quality status and trends in agriculture-dominated headwaters. We used datasets from 5 agricultural test catchments and from 167 existing monitoring locations in agricultural headwaters. Trend analysis for these locations showed a fast reduction of nutrient concentrations after the enforcement of the manure legislation (median slopes of -0.55 mg/l per decade for total nitrogen (N-tot) and -0.020 mg/l per decade for total phosphorus (P-tot)). Still, up to 76 % of the selected locations currently do not comply with either the environmental quality standards (EQSs) for nitrogen (N-tot) or phosphorus (P-tot). This indicates that further improvement of agricultural water quality is needed. We observed that weather-related variations in nutrient concentrations strongly influence the compliance testing results, both for individual locations and for the aggregated results at the national scale. Another important finding is that testing compliance for nutrients based on summer average concentrations may underestimate the agricultural impact on ecosystem health. The focus on summer concentrations does not account for the environmental impact of high winter loads from agricultural headwaters towards downstream water bodies.

  2. Managing Artificially Drained Low-Gradient Agricultural Headwaters for Enhanced Ecosystem Functions

    PubMed Central

    Pierce, Samuel C.; Kröger, Robert; Pezeshki, Reza

    2012-01-01

    Large tracts of lowlands have been drained to expand extensive agriculture into areas that were historically categorized as wasteland. This expansion in agriculture necessarily coincided with changes in ecosystem structure, biodiversity, and nutrient cycling. These changes have impacted not only the landscapes in which they occurred, but also larger water bodies receiving runoff from drained land. New approaches must append current efforts toward land conservation and restoration, as the continuing impacts to receiving waters is an issue of major environmental concern. One of these approaches is agricultural drainage management. This article reviews how this approach differs from traditional conservation efforts, the specific practices of drainage management and the current state of knowledge on the ecology of drainage ditches. A bottom-up approach is utilized, examining the effects of stochastic hydrology and anthropogenic disturbance on primary production and diversity of primary producers, with special regard given to how management can affect establishment of macrophytes and how macrophytes in agricultural landscapes alter their environment in ways that can serve to mitigate non-point source pollution and promote biodiversity in receiving waters. PMID:24832519

  3. Macroinvertebrate assemblages and secondary production in three wood-poor, second-growth, headwater streams in the Upper Peninsula of Michigan.

    NASA Astrophysics Data System (ADS)

    Entrekin, S. A.; Rosi-Marshall, E. J.; Tank, J. L.; Lamberti, G. A.

    2005-05-01

    Benthic organic matter (BOM) is retained by in-stream wood in forested streams and is often the primary food resource for aquatic macroinvertebrates. We sampled BOM and macroinvertebrates in three, forested headwater streams within the same watershed and predicted that BOM standing stocks would be high and, therefore, macroinvertebrate functional feeding groups would be dominated by shredders and gatherers. However, all streams had low annual average standing stocks of BOM (75 to 166 gAFDM m-2), and low shredder biomass (<5% of total) and gatherer biomass (<10%). Shane and Walton Creek macroinvertebrate biomass was dominated by predators (48% of total), scrapers (20%), and filterers (13%). Macroinvertebrate abundance peaked in June-July and again in November, while biomass peaked in November. In contrast, State Creek was dominated by scrapers (51%) and predators (33%), and abundance and biomass peaked in March and May, respectively. State Creek had the highest annual mean abundance (1198 individuals m-2), biomass (427 mgDM m-2), and secondary production (1000 mgDM m-2 yr-1). Macroinvertebrates in State Creek likely relied on algae and bryophytes for food and habitat. We conclude that macroinvertebrate communities in these streams are limited by BOM that was not retained in-stream because of reduced wood inputs from past logging.

  4. Export, biodegradation, and disinfection byproduct formation of dissolved and particulate organic carbon in a forested headwater stream during extreme rainfall events

    NASA Astrophysics Data System (ADS)

    Jung, B.-J.; Lee, J.-K.; Kim, H.; Park, J.-H.

    2014-11-01

    Despite an increasing recognition of the importance of extreme rainfall events for organic carbon export to inland waters, little attention has been paid to the export and reactivity of particulate organic carbon (POC) and dissolved organic C (DOC) in mountainous headwater watersheds under monsoon climates. To investigate environmental implications of storm-enhanced export of POC and DOC in mountainous headwater streams, we examined the relationships between storm magnitude and C export from a forested watershed in the Haean Basin, South Korea, during 13 storm events over 4 years and compared potentials of DOC and POC for biodegradation and disinfection byproduct (DBP) formation during an extreme rainfall event with a total rainfall of 209 mm. Event mean concentrations and export of POC increased nonlinearly above thresholds of precipitation and discharge, far exceeding the relatively small increases of DOC. The export of POC during a few storm events with a total rainfall above 200 mm per event exceeded the annual organic C export during dry years. During the 209 mm storm event, concentrations of total trihalomethanes formed by POC-derived dissolved components changed synchronously with POC concentrations, exhibiting lower levels than those formed by DOC. During a 30-day incubation at 25 °C, DOC exported during peak flow exhibited rapid biodegradation of labile components within 7 days. In contrast, the concentrations of DOC leached from POC gradually increased following the initial decline. Gradual transformation of POC-derived dissolved materials resulted in greater increases in the intensity of fulvic- and humic-like fluorescent components compared to the DOC treatment. The results highlight the significance of extreme rainfall events as "hot moments" for POC export from mountainous watersheds and also suggest that storm pulses of POC can provide potential sources of reactive organic components that can rapidly biodegrade and form DBPs after being released

  5. Storm pulses of particulate and dissolved organic carbon in a forested headwater stream and their environmental implications - importance of extreme rainfall events

    NASA Astrophysics Data System (ADS)

    Jung, B.-J.; Lee, J.-K.; Kim, H.; Park, J.-H.

    2014-05-01

    Despite recent debates on erosion-enhanced sinks of CO2 and contrasting findings on the biodegradation of recalcitrant organic materials in large rivers, little attention has been paid to the export and transformations of particulate organic carbon (POC) and dissolved organic C (DOC) in mountainous headwater watersheds under monsoon climates. To comparatively evaluate the significance of heavy monsoon rainfalls for the magnitude and environmental implications of storm-enhanced export of POC and DOC, the relationships between storm magnitude and C export were examined in a mountainous, forested headwater stream in the Haean Basin, South Korea, during 50 storm events over the 4 year monitoring period. We also compared biodegradation and disinfection byproduct (DBP) formation potentials of the DOC and POC exported during an extreme rainfall event. Event mean concentrations and export of POC increased nonlinearly above thresholds of precipitation and discharge, significantly exceeding the increases of DOC. The export of POC during a few storm events with a total rainfall above 200 mm per event exceeded the annual organic C export during dry years. During the large storm event (209 mm), concentrations of total trihalomethanes formed by POC-derived dissolved components changed synchronously with POC concentrations, exhibiting lower levels than those formed by DOC. During a 30 day incubation at 25 °C, both DOC and POC exported during peak flow initially exhibited rapid biodegradation of labile components, whereas POC-derived materials increased continuously not only DOC concentrations, but also fulvic- and humic-like fluorescent components. These results highlight the significance of extreme rainfall events as "hot moments" for POC export and also suggest that storm pulses of POC can provide potential sources of labile DOC components that can rapidly biodegrade and form DBPs in headwater streams, contrasting with other studies assuming mountainous rivers as a passive

  6. Relationship between structural features and water chemistry in boreal headwater streams--evaluation based on results from two water management survey tools suggested for Swedish forestry.

    PubMed

    Lestander, Ragna; Löfgren, Stefan; Henrikson, Lennart; Ågren, Anneli M

    2015-04-01

    Forestry may cause adverse impacts on water quality, and the forestry planning process is a key factor for the outcome of forest operation effects on stream water. To optimise environmental considerations and to identify actions needed to improve or maintain the stream biodiversity, two silvicultural water management tools, BIS+ (biodiversity, impact, sensitivity and added values) and Blue targeting, have been developed. In this study, we evaluate the links between survey variables, based on BIS+ and Blue targeting data, and water chemistry in 173 randomly selected headwater streams in the hemiboreal zone. While BIS+ and Blue targeting cannot replace more sophisticated monitoring methods necessary for classifying water quality in streams according to the EU Water Framework Directive (WFD, 2000/60/EC), our results lend support to the idea that the BIS+ protocol can be used to prioritise the protection of riparian forests. The relationship between BIS+ and water quality indicators (concentrations of nutrients and organic matter) together with data from fish studies suggests that this field protocol can be used to give reaches with higher biodiversity and conservation values a better protection. The tools indicate an ability to mitigate forestry impacts on water quality if the operations are adjusted to this knowledge in located areas.

  7. Non-free ionic transport of sodium, magnesium, and calcium in streams of two adjacent headwater catchments with different vegetation types in Japan

    NASA Astrophysics Data System (ADS)

    Terajima, Tomomi; Moriizumi, Mihoko; Nakamura, Tomohiro

    2017-01-01

    Sodium (Na), magnesium (Mg), calcium (Ca) are usually believed to occur mostly as free ions in the fresh water and consequently little is known about their chemical species. To understand the importance of non-free ionic fractions (NIF) of major metals in freshwater streams, Na, Mg, Ca, silicon (Si), and fulvic acid-like materials (FAM) were measured in streams of mountainous adjacent headwater catchments dominated by different vegetation types (planted evergreen coniferous forest and natural deciduous broadleaf forest). During both no rainfall periods and rainstorms, the proportion of NIF relative to total elements was lower in the coniferous catchment than in the deciduous catchment, although it sometimes accounted for half or more of the total concentrations of Na, Mg, and Ca in both catchments. The solubility of metal compounds was higher than the measured maximum concentrations of Na+, Mg2+, and Ca2+ to the extent that inorganic bonding was hardly possible. During no rainfall periods when FAM was slightly produced into the streams, the fluxes of NIF and Si were highly correlated (r > 0.92, p < 0.0001, n = 30) in both catchments. During a small rainstorm, the flux of NIF correlated weakly with that of Si but did not correlate with that of FAM in both catchments. In contrast, during a heavy rainstorm, the flux of NIF correlated strongly (r ⩾ 0.83, p < 0.0001, n = 26) with that of FAM in the deciduous catchment where relatively deep soil water compared to near-surface water was the predominant component of stream water. However, during the heavy rainstorm in the coniferous catchment, only the flux of NIF originated in the quick-flow component (i.e., surface or near-surface water) in stream water (ΔNIF) correlated strongly (r ⩾ 0.81, p < 0.0001, n = 22) with that of FAM. These findings imply that heavy rainstorms may enhance the bonding of the major metals with humic substances mainly in the deciduous catchment; and also exhibit that, in the headwater

  8. Effects of conservation practices on fishes, amphibians, and reptiles within agricultural streams and wetlands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation practices have been traditionally used to manage soil and water resources to improve agricultural production, and now include methods to reduce the environmental impacts of agriculture on streams and wetlands. These practices have been regularly implemented within agricultural watershed...

  9. Biomonitors of stream quality on agricultural areas: fish versus invertebrates

    USGS Publications Warehouse

    Berkman, Hilary E.; Rabeni, Charles F.; Boyle, Terence P.

    1986-01-01

    Although the utility of using either fish or benthic invertebrates as biomonitors of stream quality has been clearly shown, there is little comparative information on the usefulness of the groups in any particular situation. We compared fish to invertebrate assemblages in their ability to reflect habitat quality of sediment-impacted streams in agricultural regions of northeast Missouri, USA. Habitat quality was measured by a combination of substrate composition, riparian type, buffer strip width, and land use. Invertebrates were more sensitive to habitat differences when structural measurements, species diversity and ordination, were used. Incorporating ecological measurements, by using the Index of Biological Integrity, increased the information obtained from the fish assemblage. The differential response of the two groups was attributed to the more direct impact of sediments on invertebrate life requisites; the impact of sedimentation on fish is considered more indirect and complex, affecting feeding and reproductive mechanisms.

  10. Influence of Physical Habitat and Agricultural Contaminants on Fishes within Agricultural Drainage Ditches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural drainage ditches are used within agricultural watersheds for the removal of excess water from agricultural fields. These headwater streams have been constructed or modified so they possess an enlarged trapezoidal cross-section, straightened channels, and riparian zones lacking woody veg...

  11. Is the diet of a typical shredder related to the physical habitat of headwater streams in the Brazilian Cerrado?

    EPA Science Inventory

    Macroinvertebrates are important for processing leaf detritus in temperate streams, but studies about their role in tropical streams are scarce and often present conflicting results. We assessed the diet of Phylloicus (Trichoptera: Calamoceratidae) larvae, that is generally class...

  12. Effects of golf course construction and operation on water chemistry of headwater streams on the Precambrian Shield.

    PubMed

    Winter, Jennifer G; Dillon, Peter J

    2005-01-01

    To investigate the effects of golf course construction and operation on the water chemistry of Shield streams, we compared the water chemistry in streams draining golf courses under construction (2) and in operation (5) to streams in forested reference locations and to upstream sites where available. Streams were more alkaline and higher in base cation and nitrate concentrations downstream of operational golf courses. Levels of these parameters and total phosphorus increased over time in several streams during golf course construction through to operation. There was evidence of inputs of mercury to streams on two of the operational courses. Nutrient (phosphorus and nitrogen) concentrations were significantly related to the area of unmanaged vegetation in a 30 x 30 m area on either side of the sampling sites, and to River Bank Quality Index scores, suggesting that maintaining vegetated buffers along the stream on golf courses will reduce in-stream nutrient concentrations.

  13. Whole-stream response to nitrate loading in three streams draining agricultural landscapes.

    PubMed

    Duff, John H; Tesoriero, Anthony J; Richardson, William B; Strauss, Eric A; Munn, Mark D

    2008-01-01

    Physical, chemical, hydrologic, and biologic factors affecting nitrate (NO3(-)) removal were evaluated in three agricultural streams draining orchard/dairy and row crop settings. Using 3-d "snapshots" during biotically active periods, we estimated reach-level NO3(-) sources, NO3(-) mass balance, in-stream processing (nitrification, denitrification, and NO3(-) uptake), and NO3(-) retention potential associated with surface water transport and ground water discharge. Ground water contributed 5 to 11% to stream discharge along the study reaches and 8 to 42% of gross NO3(-) input. Streambed processes potentially reduced 45 to 75% of ground water NO3(-) before discharge to surface water. In all streams, transient storage was of little importance for surface water NO3(-) retention. Estimated nitrification (1.6-4.4 mg N m(-2) h(-1)) and unamended denitrification rates (2.0-16.3 mg N m(-2) h(-1)) in sediment slurries were high relative to pristine streams. Denitrification of NO3(-) was largely independent of nitrification because both stream and ground water were sources of NO3(-). Unamended denitrification rates extrapolated to the reach-scale accounted for <5% of NO3(-) exported from the reaches minimally reducing downstream loads. Nitrate retention as a percentage of gross NO3(-) inputs was >30% in an organic-poor, autotrophic stream with the lowest denitrification potentials and highest benthic chlorophyll a, photosynthesis/respiration ratio, pH, dissolved oxygen, and diurnal NO3(-) variation. Biotic processing potentially removed 75% of ground water NO3(-) at this site, suggesting an important role for photosynthetic assimilation of ground water NO3(-) relative to subsurface denitrification as water passed directly through benthic diatom beds.

  14. Leaf litter decomposition of native and introduced tree species of contrasting quality in headwater streams: how does the regional setting matter?

    PubMed

    Casas, J Jesús; Larrañaga, Aitor; Menéndez, Margarita; Pozo, Jesús; Basaguren, Ana; Martínez, Aingeru; Pérez, Javier; González, José M; Mollá, Salvador; Casado, Carmen; Descals, Enrique; Roblas, Neftalí; López-González, J Antonio; Valenzuela, J Luis

    2013-08-01

    Terrestrial plant litter is important in sustaining stream food webs in forested headwaters. Leaf litter quality often decreases when native species are replaced by introduced species, and a lower quality of leaf litter inputs may alter litter decomposition at sites afforested with non-native species. However, since detritivore composition and resource use plasticity may depend on the prevalent litter inputs, the extent of the alteration in decomposition can vary between streams. We tested 2 hypotheses using 2 native and 3 introduced species of tree differing in quality in 4 Iberian regions with contrasting vegetational traits: 1) decomposition rates of all plant species would be higher in regions where streams normally receive litter inputs of lower rather than higher quality; 2) a higher resource-use plasticity of detritivores in regions vegetated with plants of lower litter quality will cause a greater evenness in decomposition rates among plant species compared to regions where streams normally receive higher-quality plant litter inputs. Results showed a highly consistent interspecific ranking of decomposition rates across regions driven by litter quality, and a significant regional effect. Hypothesis 1 was supported: decomposition rates of the five litter types were generally higher in streams from regions vegetated with species producing leaf litter of low quality, possibly due to the profusion of caddisfly shredders in their communities. Hypothesis 2 was not supported: the relative differences in decomposition rates among leaf litter species remained essentially unaltered across regions. Our results suggest that, even in regions where detritivores can be comparatively efficient using resources of low quality, caution is needed particularly when afforestation programs introduce plant species of lower litter quality than the native species.

  15. Measurement of dissolved Cs-137 in stream water, soil water and groundwater at Headwater Forested Catchment in Fukushima after Fukushima Dai-ichi Nuclear Power Plant Accident

    NASA Astrophysics Data System (ADS)

    Iwagami, Sho; Tsujimura, Maki; Onda, Yuichi; Sakakibara, Koichi; Konuma, Ryohei; Sato, Yutaro

    2016-04-01

    Radiocesium migration from headwater forested catchment is important perception as output from the forest which is also input to the subsequent various land use and downstream rivers after Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. In this study, dissolved Cs-137 concentration of stream water, soil water and groundwater were measured. Observations were conducted at headwater catchment in Yamakiya district, located 35 km northwest of FDNPP from April 2014 to November 2015. Stream water discharge was monitored and stream water samples were taken at main channel and sub channel. Stream water discharge was monitored by combination of parshallflume and v-notch weir. Stream water was sampled manually at steady state condition in 3-4 month interval and also intense few hours interval sampling were conducted during rainfall events using automated water sampler. Around the sub channel, it is found that there is a regularly saturated area at the bottom of the slope, temporary saturated area which saturate during the rainy season in summer and regularly dry area. 6 interval cameras were installed to monitor the changing situation of saturated area. Suction lysimeters were installed at three areas (regularly saturated area, temporary saturated area and dry area) for sampling soil water in depth of 0.1 m and 0.3 m. Boreholes were installed at three points along the sub channel. Three boreholes with depth of 3 m, 5 m and 10 m were installed at temporary saturated area, 20 m upstream of sub channel weir. Another three boreholes with depth of 3 m, 5 m and 10 m were installed at dry area, 40 m upstream of sub channel weir. And a borehole with depth of 20 m was installed at ridge of sub catchment, 52 m upstream of sub channel weir. Groundwater was sampled by electrically powered pump and groundwater level was monitored. Also suction-free lysimeter was installed at temporary saturated area for sampling the near surface subsurface water. Soil water samples were collected

  16. Divergent patterns of abundance and age-class structure of headwater stream tadpoles in burned and unburned watersheds

    USGS Publications Warehouse

    Hossack, B.R.; Corn, P.S.; Fagre, D.B.

    2006-01-01

    Wildfire is a potential threat to many species with narrow environmental tolerances like the Rocky Mountain tailed frog (Ascaphus montanus Mittleman and Myers, 1949), which inhabits a region where the frequency and intensity of wildfires are expected to increase. We compared pre- and post-fire counts of tadpoles in eight streams in northwestern Montana to determine the effects of wildfire on A. montanus. All streams were initially sampled in 2001, 2 years before four of them burned in a large wildfire, and were resampled during the 2 years following the fire. Counts of tadpoles were similar in the two groups of streams before the fire. After the fire, tadpoles were almost twice as abundant in unburned streams than in burned streams. The fire seemed to have the greatest negative effect on abundance of age-1 tadpoles, which was reflected in the greater variation in same-stream age-class structure compared with those in unburned streams. Despite the apparent effect on tadpoles, we do not expect the wildfire to be an extirpation threat to populations in the streams that we sampled. Studies spanning a chronosequence of fires, as well as in other areas, are needed to assess the effects of fires on streams with A. montanus and to determine the severity and persistence of these effects.

  17. In-stream bioreactor for agricultural nitrate treatment.

    PubMed

    Robertson, W D; Merkley, L C

    2009-01-01

    Nitrate from agricultural activity contributes to nutrient loading in surface water bodies such as the Mississippi River. This study demonstrates a novel in-stream bioreactor that uses carbonaceous solids (woodchips) to promote denitrification of agricultural drainage. The reactor (40 m3) was trenched into the bottom of an existing agricultural drainage ditch in southern Ontario (Avon site), and flow was induced through the reactor by construction of a gravel riffle in the streambed. Over the first 1.5 yr of operation, mean influent NO3-N of 4.8 mg L(-1) was attenuated to 1.04 mg L(-1) at a mean reactor flow rate of 24 L min(-1). A series of flow-step tests, facilitated by an adjustable height outlet pipe, demonstrated that nitrate mass removal generally increased with increasing flow rate. When removal rates were not nitrate-limited, areal mass removal ranged from 11 mg N m(-2) h(-1) at 3 degrees C to 220 mg N m(-2) h(-1) at 14 degrees C (n = 27), exceeding rates reported for some surface-flow constructed wetlands in this climatic region by a factor of about 40. Over the course of the field trial, reactor flow rates decreased as a result of silt accumulation on top of the gravel infiltration gallery. Design modifications are currently being implemented to mitigate the effects of siltation. In-stream reactors have the potential to be scaled larger and could be more manageable than attempting to address nitrate loading from individual tile drains. They could also work well in combination with other nitrate control techniques.

  18. Stream-water chemistry, nutrients, and pesticides in Town Brook, a headwater stream of the Cannonsville Reservoir Watershed, Delaware County, New York, 1999

    USGS Publications Warehouse

    McHale, Michael R.; Phillips, Patrick J.

    2001-01-01

    Stream-water chemistry was monitored from January 1 through December 31, 1999, in the Town Brook watershed (TBW) in Delaware County, N.Y. to provide a basis for future evaluation of the effectiveness of Best Management Practices (BMPs) in decreasing agricultural nutrient and pesticide leaching to receiving waters. Total runoff from the watershed during 1999 was 664 millimeters (mm). Annual nutrient export (in kilograms per hectare) values were: ammonia (NH3), 0.25; nitrate (NO3-), 4.3; total nitrogen (TN), 10.6; orthophosphate (OP), 0.26; total dissolved phosphorus (TDP), 0.30; and total phosphorus (TP), 1.2 during 1999. Streamwater samples were collected during baseflow, elevated baseflow, and stormflow conditions. Stormflow, which produced the greatest flowweighted mean nutrient concentrations, represented only 41 percent of the annual runoff but accounted from 49 to 68 percent of the annual nutrient export. The highest seasonal flow-weighted mean concentrations were measured during the summer; the highest concentrations occurred during a large storm on July 4, 1999 with a recurrence interval greater than 100 years. The greatest seasonal export of dissolved nutrients (NH3, NO3-, OP, and TDP) occurred during the winter, whereas the greatest export of TN and TP was during the summer. Most of the TN and TP export during the summer occurred during the July 4 storm. That storm, together with a second large storm on September 16, 1999, accounted for the following percentages of annual export: ammonia, 17 percent; NO3-, 21 percent; TN, 45 percent; OP, 21 percent; TDP, 21 percent; and TP, 56 percent. Although these results provide information on the quantity and timing of nutrient export, they do not indicate the nutrient source nor the transport mechanisms by which nutrients are delivered to the stream. Baseflow and stormflow samples were collected for pesticide analyses at the Town Brook watershed outlet from January through July 1999. Eight pesticides and pesticide

  19. Benthic invertebrates of benchmark streams in agricultural areas of eastern Wisconsin, Western Lake Michigan Drainages

    USGS Publications Warehouse

    Rheaume, S.J.; Lenz, B.N.; Scudder, B.C.

    1996-01-01

    Information gathered from these benchmark streams can be used as a regional reference for comparison with other streams in agricultural areas, based on communities of aquatic biota, habitat, and water quality.

  20. Trace Element Distribution in Stream Bed Sediments Within AN Agricultural Catchment of the Broadkill River Watershed, Delaware, USA

    NASA Astrophysics Data System (ADS)

    Oyewumi, O.; Schreiber, M. E.

    2011-12-01

    This project examined the impact of long-term litter application on the chemical signatures of trace metals (As, Cu, Zn,) and nutrient (P) in river sediments of the Broadkill River watershed within the Delmarva Peninsula, a region of intense poultry production. Twenty-seven (27) sediment samples were collected from Broadkill River drainage systems and analyzed for acid and soluble extractable elements as well as basic soil parameters such as particle size, organic matter and soluble salts. Results showed that concentrations of the trace elements in stream sediments are approximately log-normally distributed, with concentrations increasing from upstream headwaters to downstream reaches draining predominantly agricultural areas. Using GIS maps with overlays of hydrology and land use activity, correlations between the concentrations of As, Cu, Zn and P and agricultural activities within the watershed were examined. Results indicate positive correlation between the trace elements but the connection to specific regions of agricultural land use is not clearly defined. Trace elements were also positively correlated with percent of clay and silt particles, indicating partitioning of these elements to finer grain sizes. Calculations of element enrichment factors and the geoaccumulation index revealed that most of the sediment samples were not enriched in trace elements with respect to our reference samples. However, trace element concentrations in sediments increased downgradient, suggesting that they may be influenced by anthropogenic activities within the watershed.

  1. The relative influence of nutrients and habitat on stream metabolism in agricultural streams

    USGS Publications Warehouse

    Frankforter, J.D.; Weyers, H.S.; Bales, J.D.; Moran, P.W.; Calhoun, D.L.

    2010-01-01

    Stream metabolism was measured in 33 streams across a gradient of nutrient concentrations in four agricultural areas of the USA to determine the relative influence of nutrient concentrations and habitat on primary production (GPP) and respiration (CR-24). In conjunction with the stream metabolism estimates, water quality and algal biomass samples were collected, as was an assessment of habitat in the sampling reach. When data for all study areas were combined, there were no statistically significant relations between gross primary production or community respiration and any of the independent variables. However, significant regression models were developed for three study areas for GPP (r 2 = 0.79-0.91) and CR-24 (r 2 = 0.76-0.77). Various forms of nutrients (total phosphorus and area-weighted total nitrogen loading) were significant for predicting GPP in two study areas, with habitat variables important in seven significant models. Important physical variables included light availability, precipitation, basin area, and in-stream habitat cover. Both benthic and seston chlorophyll were not found to be important explanatory variables in any of the models; however, benthic ash-free dry weight was important in two models for GPP. ?? 2009 The Author(s).

  2. By land or by stream? contribution of constrained dispersal by adult caddisflies to diversity loss from urban headwaters

    EPA Science Inventory

    The adult stage of streams insects is responsible for important life-cycle processes such as dispersal and reproduction, yet interactions of adult stream insects with terrestrial landscapes are rarely studied. This trend is especially problematic in urbanized landscapes where th...

  3. Effects of Catchment Characteristics and Disturbances on Storage and Export of Dissolved Organic Carbon in a Boreal Headwater Stream

    NASA Astrophysics Data System (ADS)

    Hillman, G. R.; Feng, J. C.; Feng, C. C.; Wang, Y.

    2004-05-01

    The transportation of large amounts of dissolved organic carbon (DOC) down a stream within a 15.51-km2 catchment in Alberta, Canada, related directly to events, such as high rainfall and beaver dam failures, that created major disturbances. A 2.3-km section of the stream was drastically altered in June 1994 when a flood wave resulting from a breached beaver dam deposited large amounts of debris and sediment within the section. Results from stream DOC storage analyses, in which a difference method was used, suggest that the organic debris dams created by the failed dam event served as both sources and sinks for DOC. Discharge and DOC measurements at hydrometric stations located at intervals along the stream indicated that storage of DOC in the stream was strongly influenced by the presence of wetlands and beaver (Castor canadensis). Disturbances occurring during periods totalling 28 days in 1994 and 17 days in 1995 accounted for 94% (1374 kg u km-2) and 84% (204 kg u km-2), respectively, of the amount of DOC exported from the catchment during the May-September period. DOC concentrations in the stream were greatest (77.0 mgL-1) near the top of the catchment where a 2-km2 fen served as the primary source of DOC. Stream DOC concentrations decreased progressively downstream to the catchment outlet where the mean concentration was 23.3 mgL-1.

  4. Evaluation of agricultural best-management practices in the Conestoga River headwaters, Pennsylvania; effects of nutrient management on water quality in the Little Conestoga Creek headwaters, 1983-89

    USGS Publications Warehouse

    Koerkle, E.H.; Fishel, D.K.; Brown, M.J.; Kostelnik, K.M.

    1996-01-01

    Water quality in the headwaters of the Little Conestoga Creek, Lancaster County, Pa., was investigated from April 1986 through September 1989 to determine possible effects of agricultural nutrient management on water quality. Nutrient management, an agricultural Best-Management Practice, was promoted in the 5.8-square-mile watershed by the U.S. Department of Agriculture Rural Clean Water Program. Nonpoint-source- agricultural contamination was evident in surface water and ground water in the watershed; the greatest contamination was in areas underlain by carbonate rock and with intensive row-crop and animal production. Initial implementation of nutrient management covered about 30 percent of applicable land and was concentrated in the Nutrient-Management Subbasin. By 1989, nutrient management covered about 45 percent of the entire Small Watershed, about 85 percent of the Nutrient- Management Subbasin, and less than 10 percent of the Nonnutrient-Management Subbasin. The number of farms implementing nutrient management increased from 14 in 1986 to 25 by 1989. Nutrient applications to cropland in the Nutrient- Management Subbasin decreased by an average of 35 percent after implementation. Comparison of base- flow surface-water quality from before and after implementation suggests that nutrient management was effective in slowing or reversing increases in concentrations of dissolved nitrate plus nitrite in the Nutrient-Management Subbasin. Although not statistically significant, the Mann-Whitney step-trend coefficient for the Nutrient-Management Subbasin was 0.8 milligram per liter, whereas trend coefficients for the Nonnutrient-Management Subbasin and the Small Watershed were 0.4 and 1.4 milligrams per liter, respectively, for the period of study. Analysis of covariance comparison of concurrent concentrations from the two sub- basins showed a significant decrease in concen- trations from the Nutrient-Management Subbasin compared to the Nonnutrient-Management Subbasin

  5. Temperature and substrate chemistry as major drivers of interregional variability of leaf microbial decomposition and cellulolytic activity in headwater streams.

    PubMed

    Fenoy, Encarnación; Casas, J Jesús; Díaz-López, Manuel; Rubio, Juan; Guil-Guerrero, J Luís; Moyano-López, Francisco J

    2016-11-01

    Abiotic factors, substrate chemistry and decomposers community composition are primary drivers of leaf litter decomposition. In soil, much of the variation in litter decomposition is explained by climate and substrate chemistry, but with a significant contribution of the specialisation of decomposer communities to degrade specific substrates (home-field advantage, HFA). In streams, however, HFA effects on litter decomposition have not been explicitly tested. We evaluated responses of microbial decomposition and β-glucosidase activity to abiotic factors, substrate and decomposer assemblages, using a reciprocal litter transplant experiment: 'ecosystem type' (mountain vs lowland streams) × 'litter chemistry' (alder vs reed). Temperature, pH and ionic concentration were higher in lowland streams. Decomposition for both species was faster in lowland streams. Decomposition of reed was more accelerated in lowland compared with mountain streams than that of alder, suggesting higher temperature sensitivity of decomposition in reed. Q10 (5°C-15°C) values of β-glucosidase activity were over 2. The alkaline pH and high ionic concentration of lowland streams depleted enzyme activity. We found similar relationships of decomposition or enzyme activity with abiotic factors for both species, suggesting limited support to the HFA hypothesis. Overall, our results suggest a prime role of temperature interacting with substrate chemistry on litter decomposition.

  6. Whole-stream response to nitrate loading in three streams draining agricultural landscapes

    USGS Publications Warehouse

    Duff, J.H.; Tesoriero, A.J.; Richardson, W.B.; Strauss, E.A.; Munn, M.D.

    2008-01-01

    Physical, chemical, hydrologic, and biologic factors affecting nitrate (NO3 −) removal were evaluated in three agricultural streams draining orchard/dairy and row crop settings. Using 3-d “snapshots” during biotically active periods, we estimated reach-level NO3 − sources, NO3 − mass balance, in-stream processing (nitrification, denitrification, and NO3 − uptake), and NO3 − retention potential associated with surface water transport and ground water discharge. Ground water contributed 5 to 11% to stream discharge along the study reaches and 8 to 42% of gross NO3 − input. Streambed processes potentially reduced 45 to 75% of ground water NO3 − before discharge to surface water. In all streams, transient storage was of little importance for surface water NO3 − retention. Estimated nitrification (1.6–4.4 mg N m−2 h−1) and unamended denitrification rates (2.0–16.3 mg N m−2 h−1) in sediment slurries were high relative to pristine streams. Denitrification of NO3 − was largely independent of nitrification because both stream and ground water were sources of NO3 − Unamended denitrification rates extrapolated to the reach-scale accounted for <5% of NO3 − exported from the reaches minimally reducing downstream loads. Nitrate retention as a percentage of gross NO3 − inputs was >30% in an organic-poor, autotrophic stream with the lowest denitrification potentials and highest benthic chlorophyll a, photosynthesis/respiration ratio, pH, dissolved oxygen, and diurnal NO3 − variation. Biotic processing potentially removed 75% of ground water NO3 − at this site, suggesting an important role for photosynthetic assimilation of ground water NO3 − relative to subsurface denitrification as water passed directly through benthic diatom beds.

  7. Relative Contributions of Leaf-associated Microorganisms to Leaf Litter Breakdown in a Nutrient-enriched Headwater Stream

    NASA Astrophysics Data System (ADS)

    Tant, C. J.; Rosemond, A. D.; Taylor, N.; Conners, D. E.; Suberkropp, K.

    2005-05-01

    Litter decomposition in streams occurs as a function of microbial and invertebrate processing, as well as abiotic factors. Abiotic factors, such as streamwater nutrient concentrations, may change the relative importance of groups of microorganisms, as well as invertebrates, to leaf breakdown. We plan to quantify the relative contributions of bacteria, fungi, and invertebrate processing on decaying leaves in a reference and treatment stream (experimentally enriched with N & P for 4.5 yrs) at the Coweeta Long Term Ecological Research site in North Carolina, USA. Leaf packs of maple or rhododendron leaves were periodically retrieved to determine decay rates. Microbial activity was measured as respiration, fungal biomass was determined by measuring ergosterol concentration, and bacterial biomass was determined by epifluorescence microscopy. Breakdown rates were dramatically faster in the nutrient enriched stream than the reference stream, associated with greater microbial activity and presumably, invertebrate feeding. Based on whole-system response by microorganisms, we predict that nutrient enrichment will lead to greater contributions of fungi, relative to bacteria, to leaf breakdown. Our results show that enrichment can fundamentally alter the rate of organic matter breakdown in streams, and will test whether enrichment also changes the relative roles of groups of organisms contributing to breakdown processes.

  8. Towards understanding the spatial and temporal characteristics of stream, hillslope, and groundwater runoff processes in a Rocky Mountain headwater catchment in Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Spencer, Sheena; Anderson, Axel; Silins, Uldis; Bladon, Kevin; Collins, Adrian

    2014-05-01

    The eastern slopes of the Rocky Mountains produce the majority of the surface water supplies for much of Alberta's population. Groundwater inputs to rivers constitutes a large component of flow in this headwater region, however limited knowledge of the interaction of groundwater-surface water sources limits the ability to predict impacts of climate and disturbance in this critical source water region. The objectives of this study are to explore the spatial and temporal dynamics of surface, hillslope, and deeper groundwater runoff processes using coupled tracer approaches to characterize their interaction in regulating streamflow dynamics at stream reach and catchment scales. The study was conducted in Star Creek (10.4 km2), which is representative of small-medium sized, front-range Rocky Mountain catchments. A network of climate stations and 6 nested hydrometric-water quality sampling stations were used to collect 5 years (2009 - 2013) of meteorological, discharge (Q), and stream water quality data. Nested stream gauging stations enabled characterization of the spatial and temporal pattern of Q and water geochemistry (cations: Na+, Mg2+, Ca2+, K+, and anions: Cl-, and SO42-) along a gradient of very steep, bedrock entrenched alpine stream reaches down through lower gradient mid-montane alluvial stream reaches. The initial phase of this work uses the stream gauging network to determine the difference in Q between stations, hydrograph baseflow separation, and mixing model analyses of geochemical parameters. These analyses suggest the runoff process is dominated by longer, deeper runoff flow pathways (groundwater). Geologic information and a conceptual model of topographic controls on hillslope-stream connectedness (after Jensco et al. 2009 and others) was used to identify sites where concentrated hillslope flow may be connected with the stream to aid in interpreting the spatial and temporal variation in Q and stream geochemistry. Strong longitudinal and seasonal

  9. Disturbance legacies of historic tie-drives persistently alter geomorphology and large wood characteristics in headwater streams, southeast Wyoming

    NASA Astrophysics Data System (ADS)

    Ruffing, Claire M.; Daniels, Melinda D.; Dwire, Kathleen A.

    2015-02-01

    Instream wood is recognized as an integral component of stream morphology in forested areas. However, few studies have evaluated the legacy effects of historic wood removal activities and associated impacts on channel morphology, contemporary wood loading, and recruitment. This study investigates the role of historic tie-driving, a widespread channel disturbance legacy, in shaping present-day stream channel conditions in southern Wyoming. Geomorphic and riparian surveys were used to assess the extent of disturbance and degree of recovery within three sets of paired tie-driven and non-driven study reaches. Tie-driven streams were narrower, shallower, and had low cross-sectional roughness and higher width-to-depth ratios when compared to non-driven streams. Study reaches in first-order tie-driven streams were characterized by predominantly plane-bed morphologies and an extremely low abundance of wood compared to paired, non-driven reaches. Wood loads in second-order tie-driven reaches were similar to non-driven reaches, but overall wood distribution varied and was more likely to accumulate in jams. Existing wood loads in tie-driven reaches exhibited a narrower range of geomorphic functions and were less stable overall, although the relative state of decay was similar across all reaches. Basal area, stream power, and reach slope were identified as key mechanisms driving wood retention in the study reaches. The results of this study suggest that contemporary channel morphology and wood loads continue to reflect disturbance histories but have not yet been affected by other contemporary disturbances expected to influence wood loads such as bark beetle infestations.

  10. Multi-scale geomorphic and hydrogeologic influences on bull trout (Salvelinus confluentus) spawning habitat in headwater streams

    NASA Astrophysics Data System (ADS)

    Bean, J. R.; Wilcox, A. C.; Woessner, W. W.; Muhlfeld, C.

    2013-12-01

    We investigated multi-scale hydrogeomorphic influences on the distribution and abundance of bull trout (Salvelinus confluentus) spawning in snowmelt- dominated streams of the upper Flathead River basin, northwestern Montana. Bull trout redds were primarily found in unconfined alluvial valley reaches (74%), which were strongly influenced by hyporheic and groundwater-stream water exchange. A considerable proportion of redds (26%), however, were patchily distributed in confined valley reaches. Among all reaches and subreaches, the abundance of redds increased with increased bankfull dimensionless shear stress and decreased with reach-average streambed grain size (p < 0.05). Within these selected reaches and subreaches, redd occurrence tended to be associated with the finest available textural facies (i.e., gravel and small cobble substrates) in concave-up bedforms with downwelling intragravel flows. Streambed temperatures tracked stream water diurnal temperature cycles to a depth of at least 25 cm. Groundwater provided substantial thermal moderation of stream water for several high-density spawning reaches. Our spawning gravel competence results indicate that bull trout select spawning areas that are potentially susceptible to flooding-induced scour during the fall and winter incubation period.

  11. LANDSCAPE INFLUENCES ON IN-STREAM BIOTIC INTEGRITY: USE OF MACROINVERTEBRATE METRICS TO IDENTIFY LANDSCAPE STRESSORS IN HEADWATER CATCHMENTS

    EPA Science Inventory

    The biotic integrity of streams is profoundly influenced by quantitative and qualitative features in the landscape of the surrounding catchment. In this study, aquatic macroinvertebrate metrics (e.g., relative abundance of Ephemeroptera, Trichoptera, and/or Plecoptera taxa, or t...

  12. Impacts of Mountaintop Removal and Valley Fill Coal Mining on C and N Processing in Terrestrial Soils and Headwater Streams.

    EPA Science Inventory

    We measured C and N cycling indicators in Appalachian watersheds impacted by mountaintop removal and valley fill (MTR/VF) coal mining, and in nearby forested watersheds. These watersheds include ephemeral, intermittent, and perennial stream reaches, and the length of time since d...

  13. Influence of leaf quality in microbial decomposition in a headwater stream in the Brazilian cerrado: a 1-year study.

    PubMed

    Sales, M A; Gonçalves, J F; Dahora, J S; Medeiros, A O

    2015-01-01

    The temporal dynamics of leaf decomposition in a tropical stream were evaluated by measuring the input of leaves from riparian vegetation. The resulting mixture of leaves was processed by decomposer microorganisms and, in particular, by aquatic hyphomycetes, the most important microorganisms associated with leaf litter decomposition. Leaf decomposition and the characteristics and activity of the microbial community were investigated over the course of 1 year; these parameters depended on the composition and availability of leaves in the stream. We assessed the biomass, activity, and community structure of the fungi associated with the decomposing leaf mixtures monthly in a tropical stream with little seasonal variation in water characteristics. The leaf material included 27 riparian species; the amount of leaves of each contributing species varied from month to month, with higher overall values in the rainy season. Leaf decomposition was slow, and leaf mass loss did not occur monthly; however, leaf mass loss was significantly lower in May and September. The values of ATP, the ergosterol concentration, and the sporulation of aquatic hyphomycetes varied during the experiment, and only the ergosterol concentration (fungal biomass) was correlated with leaf mass loss. The sporulation rates of aquatic hyphomycetes peaked at the beginning of the rainy season (October), when only three hyphomycete species were present out of the total of seven that were found during the year. In this tropical stream, where the physical and chemical characteristics of the stream water varied little during the year, we hypothesize that changes related to leaf chemical composition could be the cause of changes in decomposition and the abundance and composition of the fungal assemblages. No significant differences were found for the parameters analyzed (lignin, cellulose, fiber, phosphorous, and polyphenols).

  14. Fluvial wood function downstream of beaver versus man-made dams in headwater streams in Massachusetts, USA

    NASA Astrophysics Data System (ADS)

    David, G. C.; DeVito, L. F.; Munz, K. T.; Lisius, G.

    2014-12-01

    Fluvial wood is an essential component of stream ecosystems by providing habitat, increasing accumulation of organic matter, and increasing the processing of nutrients and other materials. However, years of channel alterations in Massachusetts have resulted in low wood loads despite the afforestation that has occurred since the early 1900s. Streams have also been impacted by a large density of dams, built during industrialization, and reduction of the beaver population. Beavers were reintroduced to Massachusetts in the 1940s and they have since migrated throughout the state. Beaver dams impound water, which traps sediment and results in the development of complex channel patterns and more ecologically productive and diverse habitats than those found adjacent to man-made dams. To develop better management practices for dam removal it is essential that we understand the geomorphic and ecologic function of wood in these channels and the interconnections with floodplain dynamics and stream water chemistry. We investigate the connections among fluvial wood, channel morphology, floodplain soil moisture dynamics, and stream water chemistry in six watersheds in Massachusetts that have been impacted by either beaver or man-made dams. We hypothesize that wood load will be significantly higher below beaver dams, subsequently altering channel morphology, water chemistry, and floodplain soil moisture. Reaches are surveyed up- and downstream of each type of dam to better understand the impact dams have on the fluvial system. Surveys include a longitudinal profile, paired with dissolved oxygen and ammonium measurements, cross-section and fluvial wood surveys, hydraulic measurements, and floodplain soil moisture mapping. We found that dissolved oxygen mirrored the channel morphology, but did not vary significantly between reaches. Wood loads were significantly larger downstream of beaver dams, which resulted in significant changes to the ammonium levels. Floodplain soil moisture

  15. Hydrology and water quality of the headwaters of the River Severn: Stream acidity recovery and interactions with plantation forestry under an improving pollution climate.

    PubMed

    Neal, Colin; Robinson, Mark; Reynolds, Brian; Neal, Margaret; Rowland, Philip; Grant, Simon; Norris, David; Williams, Bronwen; Sleep, Darren; Lawlor, Alan

    2010-10-01

    This paper presents new information on the hydrology and water quality of the eroding peatland headwaters of the River Severn in mid-Wales and links it to the impact of plantation conifer forestry further down the catchment. The Upper Hafren is dominated by low-growing peatland vegetation, with an average annual precipitation of around 2650 mm with around 250 mm evaporation. With low catchment permeability, stream response to rainfall is "flashy" with the rising limb to peak stormflow typically under an hour. The water quality is characteristically "dilute"; stormflow is acidic and enriched in aluminium and iron from the acid organic soil inputs. Baseflow is circum-neutral and calcium and bicarbonate bearing due to the inputs of groundwater enriched from weathering of the underlying rocks. Annual cycling is observed for the nutrients reflecting uptake and decomposition processes linked to the vegetation and for arsenic implying seasonal water-logging within the peat soils and underlying glacial drift. Over the decadal scale, sulphate and nitrate concentrations have declined while Gran alkalinity, dissolved organic carbon and iron have increased, indicating a reduction in stream acidification. Within the forested areas the water quality is slightly more concentrated and acidic, transgressing the boundary for acid neutralisation capacity as a threshold for biological damage. Annual sulphate and aluminium concentrations are double those observed in the Upper Hafren, reflecting the influence of forestry and the greater ability of trees to scavenge pollutant inputs from gaseous and mist/cloud-water sources compared to short vegetation. Acidification is decreasing more rapidly in the forest compared to the eroding peatland possibly due to the progressive harvesting of the mature forest reducing the scavenging of acidifying inputs. For the Lower Hafren, long-term average annual precipitation is slightly lower, with lower average altitude, at around 2520mm and evaporation

  16. [Characteristics of nitrogen and phosphorus retention in two different channel forms in a typical headwater stream in the suburb of Hefei City, China ].

    PubMed

    Li, Ru-zhong; Yang, Ji-wei; Qian, Jing; Dong, Yu-hong; Tang, Wen-kun

    2014-09-01

    To investigate the characteristics of ammonium and phosphorus retention in two typical channel forms, deep pool and winding ditch in headwater stream, four field tracer experiments were conducted in a first-order stream of Ershibu River in Hefei suburban, in which a solution of biologically active (NH4Cl and KH2PO4) and conservative (NaCl) tracers was released to the head of each reach at a constant rate. According to the data sets of tracer experiments, mechanisms of ammonium and phosphorus retention were interpreted by using OTIS model code, transient storage metrics and nutrient spiraling theory. Study results showed that: (1) The value of As in deep pool was larger than that in winding ditch, whereas its value of hydrological parameter α was lower by an order of magnitude than that of winding ditch; (2) The value of NH(4)+ -λ in main channel was higher by two to three orders of magnitude than that of NH(4)+ -λs,in transient storage zone in deep pool, but in winding ditch the two parameters were closer in terms of numerical size; (3) In deep pool, the value of NH+(4) -Vf was higher by an order of magnitude than that of SRP-Vf, in winding ditch, however, not only the two values of NH(4)+ -Vf and SRP-Vf were close to each other, but NH(4)+ -Sw was nearly equal to SRP-Sw in numerical size as well; (4) The value of NH(4)+ -U was larger by two to three orders of magnitude than that of SRP-U in deep pool, whereas in winding ditch NH(4)+ -U was just larger by one to two orders of magnitude than SRP-U in size; (5) In general, significant difference existed between deep pool and winding ditch in the effect on ammonium and phosphorus retention, and marked retention efficiency was observed for ammonium rather than SRP in deep pool.

  17. The importance of the riparian zone and in-stream processes in nitrate attenuation in undisturbed and agricultural watersheds – a review of the scientific literature

    USGS Publications Warehouse

    Ranalli, Anthony J.; Macalady, Donald L.

    2010-01-01

    We reviewed published studies from primarily glaciated regions in the United States, Canada, and Europe of the (1) transport of nitrate from terrestrial ecosystems to aquatic ecosystems, (2) attenuation of nitrate in the riparian zone of undisturbed and agricultural watersheds, (3) processes contributing to nitrate attenuation in riparian zones, (4) variation in the attenuation of nitrate in the riparian zone, and (5) importance of in-stream and hyporheic processes for nitrate attenuation in the stream channel. Our objectives were to synthesize the results of these studies and suggest methodologies to (1) monitor regional trends in nitrate concentration in undisturbed 1st order watersheds and (2) reduce nitrate loads in streams draining agricultural watersheds. Our review reveals that undisturbed headwater watersheds have been shown to be very retentive of nitrogen, but the importance of biogeochemical and hydrological riparian zone processes in retaining nitrogen in these watersheds has not been demonstrated as it has for agricultural watersheds. An understanding of the role of the riparian zone in nitrate attenuation in undisturbed watersheds is crucial because these watersheds are increasingly subject to stressors, such as changes in land use and climate, wildfire, and increases in atmospheric nitrogen deposition. In general, understanding processes controlling the concentration and flux of nitrate is critical to identifying and mapping the vulnerability of watersheds to water quality changes due to a variety of stressors. In undisturbed and agricultural watersheds we propose that understanding the importance of riparian zone processes in 2nd order and larger watersheds is critical. Research is needed that addresses the relative importance of how the following sources of nitrate along any given stream reach might change as watersheds increase in size and with flow: (1) inputs upstream from the reach, (2) tributary inflow, (3) water derived from the riparian zone

  18. The importance of the riparian zone and in-stream processes in nitrate attenuation in undisturbed and agricultural watersheds - A review of the scientific literature

    NASA Astrophysics Data System (ADS)

    Ranalli, Anthony J.; Macalady, Donald L.

    2010-08-01

    SummaryWe reviewed published studies from primarily glaciated regions in the United States, Canada, and Europe of the (1) transport of nitrate from terrestrial ecosystems to aquatic ecosystems, (2) attenuation of nitrate in the riparian zone of undisturbed and agricultural watersheds, (3) processes contributing to nitrate attenuation in riparian zones, (4) variation in the attenuation of nitrate in the riparian zone, and (5) importance of in-stream and hyporheic processes for nitrate attenuation in the stream channel. Our objectives were to synthesize the results of these studies and suggest methodologies to (1) monitor regional trends in nitrate concentration in undisturbed 1st order watersheds and (2) reduce nitrate loads in streams draining agricultural watersheds. Our review reveals that undisturbed headwater watersheds have been shown to be very retentive of nitrogen, but the importance of biogeochemical and hydrological riparian zone processes in retaining nitrogen in these watersheds has not been demonstrated as it has for agricultural watersheds. An understanding of the role of the riparian zone in nitrate attenuation in undisturbed watersheds is crucial because these watersheds are increasingly subject to stressors, such as changes in land use and climate, wildfire, and increases in atmospheric nitrogen deposition. In general, understanding processes controlling the concentration and flux of nitrate is critical to identifying and mapping the vulnerability of watersheds to water quality changes due to a variety of stressors. In undisturbed and agricultural watersheds we propose that understanding the importance of riparian zone processes in 2nd order and larger watersheds is critical. Research is needed that addresses the relative importance of how the following sources of nitrate along any given stream reach might change as watersheds increase in size and with flow: (1) inputs upstream from the reach, (2) tributary inflow, (3) water derived from the

  19. Speciation and equilibrium relations of soluble aluminum in a headwater stream at base flow and during rain events

    USGS Publications Warehouse

    Burns, Douglas A.

    1989-01-01

    In the Shenandoah National Park, Virginia, the short-term dynamics of soluble aluminum in stream water sampled during rain events differed significantly from stream water sampled during base flow conditions. Three fractions of dissolved aluminum were measured. The inorganic monomeric fraction made up approximately two thirds of the total reactive aluminum at base flow, followed by the acid-soluble and organic monomeric fractions, respectively. Equilibrium modeling showed that hydroxide complexes were the most abundant form of inorganic monomeric aluminum followed by fluoride, free aluminum ion, and sulfate. The activity of inorganic monomeric aluminum at base flow appears to be in equilibrium with an Al(OH)3 phase with solubility intermediate between microcrystalline gibbsite and natural gibbsite. During two rain events, the concentration of all three aluminum fractions increased significantly. The primary cause of the transient increase in the Al(OH)3 saturation index appears to have been the neutralization of excess H+ added by soil water through reaction with stream water HCO3- at a more rapid rate than excess inorganic monomeric aluminum could be removed from solution by hydroxide mineral precipitation. -from Author

  20. Using the Storm Water Management Model to predict urban headwater stream hydrological response to climate and land cover change

    NASA Astrophysics Data System (ADS)

    Wu, J. Y.; Thompson, J. R.; Kolka, R. K.; Franz, K. J.; Stewart, T. W.

    2013-06-01

    Streams are natural features in urban landscapes that can provide ecosystem services for urban residents. However, urban streams are under increasing pressure caused by multiple anthropogenic impacts, including increases in human population and associated impervious surface area, and accelerated climate change. The ability to anticipate these changes and better understand their effects on streams is important for developing and implementing strategies to mitigate potentially negative effects. In this study, stream flow was monitored during April-November (2011 and 2012), and the data were used to apply the Storm Water Management Model (SWMM) for five urban watersheds in central Iowa, USA representing a gradient of percent impervious surface (IS, ranging from 5.3 to 37.1%). A set of three scenarios was designed to quantify hydrological responses to independent and combined effects of climate change (18% increase in precipitation), and land cover change (absolute increases between 5.2 and 17.1%, based on separate projections of impervious surfaces for the five watersheds) for the year 2040 compared to a current condition simulation. An additional set of three scenarios examined stream response to different distributions of land cover change within a single watershed. Hydrological responses were quantified using three indices: unit-area peak discharge, flashiness (R-B Index), and runoff ratio. Stream hydrology was strongly affected by watershed percent IS. For the current condition simulation, values for all three indices were five to seven times greater in the most developed watershed compared to the least developed watershed. The climate change scenario caused a 20.8% increase in unit-area peak discharge on average across the five watersheds compared to the current condition simulation. The land cover change scenario resulted in large increases for all three indices: 49.5% for unit-area peak discharge, 39.3% for R-B Index, and 73.9% for runoff ratio, on average, for

  1. Using the Storm Water Management Model to predict urban headwater stream hydrological response to climate and land cover change

    NASA Astrophysics Data System (ADS)

    Wu, J. Y.; Thompson, J. R.; Kolka, R. K.; Franz, K. J.; Stewart, T. W.

    2013-12-01

    Streams are natural features in urban landscapes that can provide ecosystem services for urban residents. However, urban streams are under increasing pressure caused by multiple anthropogenic impacts, including increases in human population and associated impervious surface area, and accelerated climate change. The ability to anticipate these changes and better understand their effects on streams is important for developing and implementing strategies to mitigate potentially negative effects. In this study, stream flow was monitored during April-November (2011 and 2012), and the data were used to apply the Storm Water Management Model (SWMM) for five urban watersheds in central Iowa, USA, representing a gradient of percent impervious surface (IS, ranging from 5.3 to 37.1%). A set of three scenarios was designed to quantify hydrological responses to independent and combined effects of climate change (18% increase in precipitation), and land cover change (absolute increases between 5.2 and 17.1%, based on separate projections of impervious surfaces for the five watersheds) for the year 2040 compared to a current condition simulation. An additional set of three scenarios examined stream response to different distributions of land cover change within a single watershed. Hydrological responses were quantified using three indices: unit-area peak discharge, flashiness (R-B Index; Richards-Baker Index), and runoff ratio. Stream hydrology was strongly affected by watershed percent IS. For the current condition simulation, values for all three indices were five to seven times greater in the most developed watershed compared to the least developed watershed. The climate change scenario caused a 20.8% increase in unit-area peak discharge on average across the five watersheds compared to the current condition simulation. The land cover change scenario resulted in large increases for all three indices: 49.5% for unit-area peak discharge, 39.3% for R-B Index, and 73.9% for runoff

  2. A coupled geochemical and biogeochemical approach to characterize the bioreactivity of dissolved organic matter from a headwater stream

    NASA Astrophysics Data System (ADS)

    Sleighter, Rachel L.; Cory, Rose M.; Kaplan, Louis A.; Abdulla, Hussain A. N.; Hatcher, Patrick G.

    2014-08-01

    The bioreactivity or susceptibility of dissolved organic matter (DOM) to microbial degradation in streams and rivers is of critical importance to global change studies, but a comprehensive understanding of DOM bioreactivity has been elusive due, in part, to the stunningly diverse assemblages of organic molecules within DOM. We approach this problem by employing a range of techniques to characterize DOM as it flows through biofilm reactors: dissolved organic carbon (DOC) concentrations, excitation emission matrix spectroscopy (EEMs), and ultrahigh resolution mass spectrometry. The EEMs and mass spectral data were analyzed using a combination of multivariate statistical approaches. We found that 45% of stream water DOC was biodegraded by microorganisms, including 31-45% of the humic DOC. This bioreactive DOM separated into two different groups: (1) H/C centered at 1.5 with O/C 0.1-0.5 or (2) low H/C of 0.5-1.0 spanning O/C 0.2-0.7 that were positively correlated (Spearman ranking) with chromophoric and fluorescent DOM (CDOM and FDOM, respectively). DOM that was more recalcitrant and resistant to microbial degradation aligned tightly in the center of the van Krevelen space (H/C 1.0-1.5, O/C 0.25-0.6) and negatively correlated (Spearman ranking) with CDOM and FDOM. These findings were supported further by principal component analysis and 2-D correlation analysis of the relative magnitudes of the mass spectral peaks assigned to molecular formulas. This study demonstrates that our approach of processing stream water through bioreactors followed by EEMs and FTICR-MS analyses, in combination with multivariate statistical analysis, allows for precise, robust characterization of compound bioreactivity and associated molecular level composition.

  3. Nitrate Removal Along a Colorado Montane Headwater Stream: the Role of Bidirectional Hydrologic Exchange at Reach to Catchment Scales

    NASA Astrophysics Data System (ADS)

    Smull, E. M.; Gooseff, M. N.

    2015-12-01

    Bidirectional hydrologic exchanges between streams and aquifers can influence nutrient concentrations (physical influx/efflux via gaining/losing water), and/or can facilitate biogeochemical cycling (physical and biological processes). Such exchanges therefore act to influence nutrient fate and transport, and have not yet been captured and incorporated into our understanding of stream nutrient retention and export. Along Colorado's Front Range, research in alpine and subalpine catchments has documented consistent increases in nitrate export, likely due to increased nitrogen deposition from industrialization and fertilization in eastern Colorado. The state of montane zone catchments with respect to their ability to cycle nitrate is not as well understood, however, and such ecosystems have complex hydrologic regimes relative to alpine areas. We applied a fully informed hydrologic mass balance model and nitrate mass balance model that include gross gains and gross losses (bidirectional exchanges) along a 1000 m study reach, to better understand physical and biological nitrate removal for a Colorado montane zone catchment, Lower Gordon Gulch. We collected data during five synoptic stream tracer and sampling campaigns along our study reach during the 2014-2015 water year, and installed wells along the north-facing and south-facing riparian corridor to capture changing water tables. Four distinct hydrologic regimes are captured in our results, including two experiments during baseflow, one experiment following snowmelt, one experiment following late-spring rainfall, and one experiment during the start of the seasonal hydrograph recession in mid-summer. Results show a transition from hydrologic sources of nitrate following snowmelt, to biological sources during rainfall, to biological removal during summer, and finally to hydrologic removal during baseflow. Our findings also corroborate earlier work in montane zone streams that shows preferential flow on south

  4. Large wood recruitment and redistribution in headwater streams in the southern Oregon Coast Range, U.S.A

    USGS Publications Warehouse

    May, Christine L.; Gresswell, Robert E.

    2003-01-01

    Large wood recruitment and redistribution mechanisms were investigated in a 3.9 km2 basin with an old-growth Pseudotsuga menziesii (Mirb.) Franco and Tsuga heterophylla (Raf.) Sarg. forest, located in the southern Coast Range of Oregon. Stream size and topographic setting strongly influenced processes that delivered wood to the channel network. In small colluvial channels draining steep hillslopes, processes associated with slope instability dominated large wood recruitment. In the larger alluvial channel, windthrow was the dominant recruitment process from the local riparian area. Consequently, colluvial channels received wood from further upslope than the alluvial channel. Input and redistribution processes influenced piece location relative to the direction of flow and thus, affected the functional role of wood. Wood recruited directly from local hillslopes and riparian areas was typically positioned adjacent to the channel or spanned its full width, and trapped sediment and wood in transport. In contrast, wood that had been fluvially redistributed was commonly located in mid-channel positions and was associated with scouring of the streambed and banks. Debris flows were a unique mechanism for creating large accumulations of wood in small streams that lacked the capacity for abundant fluvial transport of wood, and for transporting wood that was longer than the bank-full width of the channel.

  5. Sediment and nutrient delivery from thermokarst features in the foothills of the North Slope, Alaska: Potential impacts on headwater stream ecosystems

    USGS Publications Warehouse

    Bowden, W.B.; Gooseff, M.N.; Balser, A.; Green, A.; Peterson, B.J.; Bradford, J.

    2008-01-01

    Permafrost is a defining characteristic of the Arctic environment. However, climate warming is thawing permafrost in many areas leading to failures in soil structure called thermokarst. An extensive survey of a 600 km2 area in and around the Toolik Lake Natural Research Area (TLNRA) revealed at least 34 thermokarst features, two thirds of which were new since ???1980 when a high resolution aerial survey of the area was done. Most of these thermokarst features were associated with headwater streams or lakes. We have measured significantly increased sediment and nutrient loading from thermokarst features to streams in two well-studied locations near the TLNRA. One small thermokarst gully that formed in 2003 on the Toolik River in a 0.9 km2 subcatchment delivered more sediment to the river than is normally delivered in 18 years from 132 km2 in the adjacent upper Kuparuk River basin (a long-term monitoring reference site). Ammonium, nitrate, and phosphate concentrations downstream from a thermokarst feature on Imnavait Creek increased significantly compared to upstream reference concentrations and the increased concentrations persisted over the period of sampling (1999-2005). The downstream concentrations were similar to those we have used in a long-term experimental manipulation of the Kuparuk River and that have significantly altered the structure and function of that river. A subsampling of other thermokarst features from the extensive regional survey showed that concentrations of ammonium, nitrate, and phosphate were always higher downstream of the thermokarst features. Our previous research has shown that even minor increases in nutrient loading stimulate primary and secondary production. However, increased sediment loading could interfere with benthic communities and change the responses to increased nutrient delivery. Although the terrestrial area impacted by thermokarsts is limited, the aquatic habitat altered by these failures can be extensive. If warming in

  6. Multiple scales of temporal variability in ecosystem metabolism rates: results from two years of continuous monitoring in a forested headwater stream

    SciTech Connect

    Roberts, Brian J; Mulholland, Patrick J; Hill, Walter

    2007-01-01

    Headwater streams are key sites of nutrient and organic matter processing and retention, but little is known about temporal variability in gross primary production (GPP) and ecosystem respiration (ER) rates as a result of the short duration of most ecosystem metabolism measurements in lotic ecosystems. We examined temporal variability and controls on ecosystem metabolism by measuring daily rates continuously for two years in Walker Branch, a first-order deciduous forest stream. Four important scales of temporal variability in ecosystem metabolism rates were identified: (1) seasonal, (2) day-to-day, (3) episodic (storm-related), and (4) inter-annual. Seasonal patterns were largely controlled by the leaf phenology and productivity of the deciduous riparian forest. Walker Branch was strongly net heterotrophic throughout the year with the exception of the open-canopy spring when GPP and ER rates were similar. Day-to-day variability in weather conditions influenced light reaching the streambed, resulting in high day-to-day variability in GPP particularly during spring (daily light levels explained 84% of the variance in daily GPP in April). Episodic storms depressed GPP for several days in spring, but increased GPP in autumn by removing leaves shading the streambed. Storms depressed ER initially, but then stimulated ER to 2-3 times pre-storm levels for several days. Walker Branch was strongly net heterotrophic in both years of the study (NEP = -1156 and -773 g O2 m-2 y-1), with annual GPP being similar (488 and 519 g O2 m-2 y-1) but annual ER being higher in 2004 than 2005 (-1645 vs. -1292 g O2 m-2 y-1). Inter-annual variability in ecosystem metabolism (assessed by comparing 2004 and 2005 rates with previous measurements) was the result of the storm frequency and timing and the size of the spring macroalgal bloom. Changes in local climate can have substantial impacts on stream ecosystem metabolism rates and ultimately influence the carbon source and sink properties of

  7. Submersible UV-Vis Spectroscopy for Quantifying Streamwater Organic Carbon Dynamics: Implementation and Challenges before and after Forest Harvest in a Headwater Stream

    PubMed Central

    Jollymore, Ashlee; Johnson, Mark S.; Hawthorne, Iain

    2012-01-01

    Organic material, including total and dissolved organic carbon (DOC), is ubiquitous within aquatic ecosystems, playing a variety of important and diverse biogeochemical and ecological roles. Determining how land-use changes affect DOC concentrations and bioavailability within aquatic ecosystems is an important means of evaluating the effects on ecological productivity and biogeochemical cycling. This paper presents a methodology case study looking at the deployment of a submersible UV-Vis absorbance spectrophotometer (UV-Vis spectro∷lyzer model, s∷can, Vienna, Austria) to determine stream organic carbon dynamics within a headwater catchment located near Campbell River (British Columbia, Canada). Field-based absorbance measurements of DOC were made before and after forest harvest, highlighting the advantages of high temporal resolution compared to traditional grab sampling and laboratory measurements. Details of remote deployment are described. High-frequency DOC data is explored by resampling the 30 min time series with a range of resampling time intervals (from daily to weekly time steps). DOC export was calculated for three months from the post-harvest data and resampled time series, showing that sampling frequency has a profound effect on total DOC export. DOC exports derived from weekly measurements were found to underestimate export by as much as 30% compared to DOC export calculated from high-frequency data. Additionally, the importance of the ability to remotely monitor the system through a recently deployed wireless connection is emphasized by examining causes of prior data losses, and how such losses may be prevented through the ability to react when environmental or power disturbances cause system interruption and data loss. PMID:22666002

  8. Submersible UV-Vis spectroscopy for quantifying streamwater organic carbon dynamics: implementation and challenges before and after forest harvest in a headwater stream.

    PubMed

    Jollymore, Ashlee; Johnson, Mark S; Hawthorne, Iain

    2012-01-01

    Organic material, including total and dissolved organic carbon (DOC), is ubiquitous within aquatic ecosystems, playing a variety of important and diverse biogeochemical and ecological roles. Determining how land-use changes affect DOC concentrations and bioavailability within aquatic ecosystems is an important means of evaluating the effects on ecological productivity and biogeochemical cycling. This paper presents a methodology case study looking at the deployment of a submersible UV-Vis absorbance spectrophotometer (UV-Vis spectro::lyzer model, s::can, Vienna, Austria) to determine stream organic carbon dynamics within a headwater catchment located near Campbell River (British Columbia, Canada). Field-based absorbance measurements of DOC were made before and after forest harvest, highlighting the advantages of high temporal resolution compared to traditional grab sampling and laboratory measurements. Details of remote deployment are described. High-frequency DOC data is explored by resampling the 30 min time series with a range of resampling time intervals (from daily to weekly time steps). DOC export was calculated for three months from the post-harvest data and resampled time series, showing that sampling frequency has a profound effect on total DOC export. DOC exports derived from weekly measurements were found to underestimate export by as much as 30% compared to DOC export calculated from high-frequency data. Additionally, the importance of the ability to remotely monitor the system through a recently deployed wireless connection is emphasized by examining causes of prior data losses, and how such losses may be prevented through the ability to react when environmental or power disturbances cause system interruption and data loss.

  9. Contrasting Contaminant Occurrence in Urban and Agricultural Streams in the Midwestern and Southeastern United States

    NASA Astrophysics Data System (ADS)

    Van Metre, P. C.

    2015-12-01

    Streams in urban and agricultural settings are known to have many anthropogenic chemical stressors; however, there are important differences in the occurrence of pesticides, metals, legacy contaminants, combustion byproducts, and contaminants of emerging concern between the two settings. In 2013 and 2014, the U.S. Geological Survey characterized water-quality stressors and ecological conditions in 100 streams in the Midwestern U.S. and 115 streams in the southeastern U.S., respectively. Water samples were collected weekly for 10-12 weeks during spring and early summer. Habitat, sediment chemistry, and ecological communities were sampled once at the end of the water-sampling period. Water and(or) sediment samples were analyzed for pesticides, nutrients, wastewater indicator compounds, polycyclic aromatic hydrocarbons, halogenated compounds, metals, volatile organic compounds, and pharmaceuticals. The spatial and temporal distribution of detected compounds and health-based-benchmark-normalized summations of compound mixtures indicate important differences between agricultural and urban settings. In general, urban streams are affected by more complex chemical mixtures than agricultural streams. Although higher herbicide and nutrient concentrations generally are found in agricultural settings, the more frequent occurrence of insecticides, hydrocarbons, halogenated compounds, and metals in urban settings indicates higher potential toxicity in urban streams than in agricultural streams. The effects of these complex mixtures and other stressors are being evaluated in relation to stream ecological communities at the regional scale.

  10. Effect of land use and hydrological processes on Escherichia coli concentrations in streams of tropical, humid headwater catchments.

    PubMed

    Rochelle-Newall, Emma J; Ribolzi, Olivier; Viguier, Marion; Thammahacksa, Chanthamousone; Silvera, Norbert; Latsachack, Keooudone; Dinh, Rinh Pham; Naporn, Piyapong; Sy, Hai Tran; Soulileuth, Bounsamay; Hmaimum, Nikom; Sisouvanh, Pem; Robain, Henri; Janeau, Jean-Louis; Valentin, Christian; Boithias, Laurie; Pierret, Alain

    2016-09-08

    Lack of access to clean water and adequate sanitation continues to be a major brake on development. Here we present the results of a 12-month investigation into the dynamics of Escherichia coli, a commonly used indicator of faecal contamination in water supplies, in three small, rural catchments in Laos, Thailand and Vietnam. We show that land use and hydrology are major controlling factors of E. coli concentrations in streamwater and that the relative importance of these two factors varies between the dry and wet seasons. In all three catchments, the highest concentrations were observed during the wet season when storm events and overland flow were highest. However, smaller peaks of E. coli concentration were also observed during the dry season. These latter correspond to periods of intense farming activities and small, episodic rain events. Furthermore, vegetation type, through land use and soil surface crusting, combined with mammalian presence play an important role in determining E. coli loads in the streams. Finally, sampling during stormflow revealed the importance of having appropriate sampling protocols if information on maximum contamination levels is required as grab sampling at a fixed time step may miss important peaks in E. coli numbers.

  11. Effect of land use and hydrological processes on Escherichia coli concentrations in streams of tropical, humid headwater catchments

    NASA Astrophysics Data System (ADS)

    Rochelle-Newall, Emma J.; Ribolzi, Olivier; Viguier, Marion; Thammahacksa, Chanthamousone; Silvera, Norbert; Latsachack, Keooudone; Dinh, Rinh Pham; Naporn, Piyapong; Sy, Hai Tran; Soulileuth, Bounsamay; Hmaimum, Nikom; Sisouvanh, Pem; Robain, Henri; Janeau, Jean-Louis; Valentin, Christian; Boithias, Laurie; Pierret, Alain

    2016-09-01

    Lack of access to clean water and adequate sanitation continues to be a major brake on development. Here we present the results of a 12-month investigation into the dynamics of Escherichia coli, a commonly used indicator of faecal contamination in water supplies, in three small, rural catchments in Laos, Thailand and Vietnam. We show that land use and hydrology are major controlling factors of E. coli concentrations in streamwater and that the relative importance of these two factors varies between the dry and wet seasons. In all three catchments, the highest concentrations were observed during the wet season when storm events and overland flow were highest. However, smaller peaks of E. coli concentration were also observed during the dry season. These latter correspond to periods of intense farming activities and small, episodic rain events. Furthermore, vegetation type, through land use and soil surface crusting, combined with mammalian presence play an important role in determining E. coli loads in the streams. Finally, sampling during stormflow revealed the importance of having appropriate sampling protocols if information on maximum contamination levels is required as grab sampling at a fixed time step may miss important peaks in E. coli numbers.

  12. Effect of land use and hydrological processes on Escherichia coli concentrations in streams of tropical, humid headwater catchments

    PubMed Central

    Rochelle-Newall, Emma J.; Ribolzi, Olivier; Viguier, Marion; Thammahacksa, Chanthamousone; Silvera, Norbert; Latsachack, Keooudone; Dinh, Rinh Pham; Naporn, Piyapong; Sy, Hai Tran; Soulileuth, Bounsamay; Hmaimum, Nikom; Sisouvanh, Pem; Robain, Henri; Janeau, Jean-Louis; Valentin, Christian; Boithias, Laurie; Pierret, Alain

    2016-01-01

    Lack of access to clean water and adequate sanitation continues to be a major brake on development. Here we present the results of a 12-month investigation into the dynamics of Escherichia coli, a commonly used indicator of faecal contamination in water supplies, in three small, rural catchments in Laos, Thailand and Vietnam. We show that land use and hydrology are major controlling factors of E. coli concentrations in streamwater and that the relative importance of these two factors varies between the dry and wet seasons. In all three catchments, the highest concentrations were observed during the wet season when storm events and overland flow were highest. However, smaller peaks of E. coli concentration were also observed during the dry season. These latter correspond to periods of intense farming activities and small, episodic rain events. Furthermore, vegetation type, through land use and soil surface crusting, combined with mammalian presence play an important role in determining E. coli loads in the streams. Finally, sampling during stormflow revealed the importance of having appropriate sampling protocols if information on maximum contamination levels is required as grab sampling at a fixed time step may miss important peaks in E. coli numbers. PMID:27604854

  13. Particulate nitrogen exports in stream runoff exceed dissolved nitrogen forms during large tropical storms in a temperate, headwater, forested watershed

    NASA Astrophysics Data System (ADS)

    Inamdar, Shreeram; Dhillon, Gurbir; Singh, Shatrughan; Parr, Thomas; Qin, Zhixuan

    2015-08-01

    Although lasting only a fraction of the year, large storms may represent a significant, but highly variable, control on watershed nitrogen (N) fluxes. We determined the exports of particulate N (PN) and total dissolved N including nitrate-N (NO3-N) and dissolved organic N (DON) in streamflow from a 12 ha temperate forested watershed. Sampling was performed for 15 storms over September 2010 to December 2012 and included four large tropical storms—Nicole (2010), Irene and Lee (2011), and Sandy (2012). PN composed a substantial portion (39-87%) of the storm event N export with storms constituting 65% of the 2011 PN export. Tropical storm Irene alone generated 1.76 kg N ha-1 of PN which was 27% of the annual watershed N (6.43 kg N ha-1) export for 2011. In contrast, tropical storm Sandy (October 2012) yielded low sediment and PN exports, likely due to low precipitation intensity and a freshly fallen leaf cover that may have reduced soil erosion. Stream water concentrations of PN, NO3-N, and DON ranged from 0-17.5, 0-2.02, and 0.01-0.54 mg N L-1, respectively. Nitrate-N concentrations displayed a dilution trajectory for peak stormflows suggesting supply limitation, a response that was not as strong for PN. These results underscore the importance of large storms for PN export which is significant given that climate-change predictions indicate an increasing intensity of large tropical storms for the northeast U.S.. Elevated PN exports could further exacerbate water quality and eutrophication problems in sensitive aquatic ecosystems already subjected to excess dissolved nitrogen loads.

  14. RELATIONS BETWEEN LAND USE AND STREAM NUTRIENT CONCENTRATIONS FOR SMALL WATERSHEDS IN THE GEORGIA PIEDMONT

    EPA Science Inventory

    We have been sampling nutrient concentrations in 17 headwater streams within the South Fork Broad River (SFBR) watershed on a monthly basis since November 2001. The streams were classified as either developed (n=4), agriculture/pasture (n=4), mixed land use (n=6) or forested (n=3...

  15. Impacts of climate and catastrophic forest changes on streamflow and water balance in a mountainous headwater stream in Southern Alberta

    NASA Astrophysics Data System (ADS)

    Mahat, V.; Anderson, A.

    2013-12-01

    Rivers in Southern Alberta are vulnerable to climate change because much of the river water originates as snow in the eastern slopes of the Rocky Mountains. Changes in likelihood of forest disturbance (wildfire, insects, logging, etc.) may also have impacts that are compounded by climate change. This study evaluates the impacts of climate and forest changes on streamflow in the upper parts of the Oldman River in Southern Alberta using a conceptual hydrological model, HBV-EC (Hydrologiska Byråns attenbalansavdelning, Environment Canada), in combination with a stochastic weather generator (LARS-WG) driven by GCM (global climate model) output climate data. Three climate change scenarios (A1B, A2 and B1) are selected to cover the range of possible future climate conditions (2020s, 2050s, and 2080s). The GCM projected less than a 10% increase in precipitation in winter and a similar amount of precipitation decrease in summer. These changes in projected precipitation resulted in up to a 200% (9.3 mm) increase in winter streamflow in February and up to a 63% (31.2 mm) decrease in summer flow in June. Flow also decreased in July and August, when irrigation is important; these reduced river flows during this season could impact agriculture production. The amplification in the streamflow is mostly driven by the projected increase in temperature that is predicted to melt winter snow earlier, resulting in lower water availability during the summer. Uncertainty analysis was completed using a guided GLUE (generalized likelihood uncertainty estimation) approach to obtain the best 100 parameter sets and associated ranges of streamflows. The impacts of uncertainty in streamflows were higher in spring and summer than in winter and fall. Forest change compounded the climate change impact by increasing the winter flow; however, it did not reduce the summer flow.

  16. Evaluation of agricultural best-management practices in the Conestoga River headwaters, Pennsylvania; methods of data collection and analysis and description of study areas

    USGS Publications Warehouse

    Chichester, Douglas C.

    1988-01-01

    The U.S. Geological Survey is conducting a water quality study as part of the nationally implemented Rural Clean Water Program in the headwaters of the Conestoga River, Pennsylvania. The study, which began in 1982, was designed to determine the effect of agricultural best management practices on surface--and groundwater quality. The study was concentrated in four areas within the intensively farmed, carbonate rock terrane located predominately in Lancaster County, Pennsylvania. These areas were divided into three monitoring components: (1) a Regional study area (188 sq mi): (2) a Small Watershed study area (5.82 sq mi); and (3) two field site study areas, Field-Site 1 (22.1 acres) and Field 2 (47.5 acres). The type of water quality data and the methods of data collection and analysis are presented. The monitoring strategy and description of the study areas are discussed. The locations and descriptions for all data collection locations at the four study areas are provided. (USGS)

  17. Relationship of wooded riparian zones and runoff potential to fish community composition in agricultural streams

    USGS Publications Warehouse

    Stauffer, J.C.; Goldstein, R.M.; Newman, R.M.

    2000-01-01

    The relationship of fish community composition to riparian cover and runoff potential was investigated in 20 streams in the agricultural Minnesota River Basin during the summer of 1997. Analysis of variance indicated significant differences in fish community composition due to both riparian cover (wooded versus open) and runoff potential (high or low). Streams with wooded riparian zones had higher index of biological integrity (IBI) scores, species richness, diversity, and percentages of benthic insectivores and herbivores than streams with open riparian zones. Streams with low runoff potential had higher IBI scores and species richness than streams with high runoff potential. The riparian cover and runoff potential interaction was marginally significant with respect to IBI scores and species richness, suggesting a weak interaction between the two factors. Although both factors were important, riparian cover influenced fish community composition more than runoff potential in these streams, indicating that local factors (close to the stream) dominated landscape- or basin-level factors.

  18. Long-term trends in climate and hydrology in an agricultural headwater watershed of central Pennsylvania, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Climate change has emerged as a key issue facing agriculture and water resources in the US. Long-term (1968-2012) temperature, precipitation and streamflow data from a small (7.3 km2) watershed in east-central Pennsylvania was used to examine climatic and hydrologic trends in the context of recent c...

  19. Assessment of In-Stream Phosphorus Dynamics in Agricultural Drainage Ditches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The intensive row crop agricultural systems in the Midwestern United States can enrich surface waters with nutrients. This project was conducted to evaluate the in-stream processing of P in agricultural ditches. Phosphorus injection studies were conducted at seven sites along three drainage ditches ...

  20. Evaluation of agricultural best-management practices in the Conestoga River headwaters, Pennsylvania; a summary report, 1982-90

    USGS Publications Warehouse

    Lietman, Patricia L.

    1997-01-01

    Pipe-outlet terracing was effective in reducing sediment losses from a field site, but total nitrogen and phosphorus losses with runoff were not significantly different before and after terracing. Median concentrations of dissolved nitrate in several ground-water sampling locations increased after terrace installation. Dissolved nitrate concentrations in ground water decreased significantly after nutrient-management implementation. Findings indicate that agricultural-management practices to improve water quality are most effective if their overall design effects on surface- and ground-water systems are considered in their design.

  1. Impacts of pesticides and natural stressors on leaf litter decomposition in agricultural streams.

    PubMed

    Rasmussen, Jes Jesssen; Wiberg-Larsen, Peter; Baattrup-Pedersen, Annette; Monberg, Rikke Juul; Kronvang, Brian

    2012-02-01

    Agricultural pesticides are known to significantly impact the composition of communities in stream ecosystems. Moreover, agricultural streams are often characterised by loss of physical habitat diversity which may impose additional stress resulting from suboptimal environmental conditions. We surveyed pesticide contamination and rates of leaf litter decomposition in 14 1st and 2nd order Danish streams using litter bags with coarse and fine mesh sizes. Two sites differing in physical habitat complexity were sampled in each stream, and we used this approach to differentiate the effects of pesticides between sites with uniform (silt and sand) and more heterogeneous physical properties. Microbial litter decomposition was reduced by a factor two to four in agricultural streams compared to forested streams, and we found that the rate of microbial litter decomposition responded most strongly to pesticide toxicity for microorganisms and not to eutrophication. Moreover, the rate of microbial litter decomposition was generally 50% lower at sites with uniform physical habitats dominated by soft substrate compared to the sites with more heterogeneous physical habitats. The rate of macroinvertebrate shredding activity was governed by the density of shredders, and the density of shredders was not correlated to pesticide contamination mainly due to high abundances of the amphipod Gammarus pulex at all sites. Our study provides the first field based results on the importance of multiple stressors and their potential to increase the effect of agricultural pesticides on important ecosystem processes.

  2. Temporal trends and relationships between groundwater and surface water nitrate concentrations in headwater agricultural catchments: what can we learn from a monitoring over 20 years?

    NASA Astrophysics Data System (ADS)

    Fovet, O.; Gascuel, C.; Faucheux, M.; Ruiz, L.; Aquilina, L.; Molenat, J.

    2012-04-01

    The intensification of agriculture during the 20th century led to strong issues on water quality related to nutrients enrichments in groundwater and surface water. In this context, Western France is an extreme case regarding to the high nitrate concentrations observed in rivers (around 7 mg N-NO3/l1 in average). In the early 90ies, an Environmental Research Observatory AgrHys has been created and instrumented to investigate the response time of hydro-chemical fluxes to landuse changes in agrohydrosystems. This observatory is part of a French Catchments Network (Critical Zone Observatory), and composed of two sites. Kervidy-Naizin monitoring has been recently analyzed to identify the effect of climatic factors on water quality, while we focus here on Kerbernez site. This site is composed of 5 first-order and adjacent catchments, less than 1 km^2, where land use agricultural practices have been recorded with precision. Hydrological, hydrochemical and climatic data were recorded over the last 20 years. Since 2001, the monitoring was extended to groundwater using piezometric measurements and chemical analyses. Previous studies [1] suggested that nitrate transport was essentially a transport limited process on this site. The long-term and extensive monitoring programs can help us understanding the effect of agricultural practices on nitrate concentration in streams. We reconsider this hypothesis 10 years later by analyzing if the streams nitrate concentrations reacted to the changes in agricultural practices. Different protocols of monitoring (manual vs. automatic measurements) are compared though the annual water fluxes at the outlet in order to estimate the incertitude on water discharge for such small streams. All the water balances computed were not equilibrated suggesting important subsurface flows. The high contribution of the shallow groundwater is confirmed by the hydrochemical data. Mean annual nitrate concentration in the drainage water is computed using two

  3. Assessing the dynamics of fluvial nitrate over short stream reaches in watersheds impacted by agricultural pollution

    NASA Astrophysics Data System (ADS)

    Gurley, J. W.; Showers, W. J.; Osburn, C. L.; Levine, J. F.

    2011-12-01

    Elevated nitrate levels in many aquatic systems can be related to changes in land use/land cover and agricultural practices. However, these relations are often based on synoptic point sampling of independent drainage basins, neglecting in-stream processes that may affect nitrate dynamics upstream and resulting in correlations based on large spatial coverage. Understanding regional trends and implementing effective management strategies are hindered by the inability to determine the sources and dynamics of nitrate over stream reaches at small scales. To address this issue, continuous downstream measurements were made on two low-order streams draining small watersheds of mixed agricultural and natural land cover. Small, yet significant changes in nitrate concentration were observed at river lengths ranging from a few hundred meters to kilometers. This variability was related to the inputs of smaller streams and artificial drainages as well as the presence of natural dams. These patterns represent downstream nitrate variation as a stepped progression with little to no gradual in-stream processing over short distances. On both streams, average nitrate concentration downstream of inputs showed a positive correlation with proportion of agricultural land use within the input drainage basin while proportion of wetland cover correlated negatively with nitrate concentration in one stream. Reduction of nitrate downstream of natural dams indicates that these structures may serve as zones of nitrate removal in these low-order streams. These findings demonstrate the dynamic nature of nitrate and suggest that small-scale terrestrial and in-stream processes are of ecological importance when determining riverine nitrate influences in agricultural watersheds.

  4. Persistent Effects of Oil Palm Plantation Agriculture on Freshwater Stream Function in Indonesian Borneo

    NASA Astrophysics Data System (ADS)

    Carlson, K. M.; Curran, L.; Ratnasari, D.

    2012-12-01

    Conversion of forests to agricultural land uses alters freshwater stream ecosystems by changing flows of physical, chemical, and biological stream inputs. In contrast with annual agricultural crops, oil palm agribusiness may have distinctive effects on stream function because these plantations replace existing land cover with 1,000-20,000 ha tree-like monocultures that have 20-30 year rotation cycles. From 2008 to 2012 in Kalimantan (Indonesian Borneo), we measured water temperature, metabolism, and sediment and nutrient loads in four streams draining watersheds dominated (> ~70%) by intact and logged forests, agroforests and agricultural fallows, and young (< 3 y) and mature (> 10 y) oil palm plantations. We find that mean daily stream temperature was elevated 12% at the mature and 8% at the young oil palm site compared to the forest stream (25.5 ± 0.3°C). No clear relationship emerged between land cover type and ecosystem respiration (ER, g O2 m-2 d-1) or gross primary production (GPP, g O2 m-2 d-1). Yet GPP:ER ratios were 600% and 650% greater at young and mature oil palm watersheds, respectively, than the forested watershed (0.020 ± 0.005). Sediment loads (t d-1) across measured water yields (m d-1) were higher in the young oil palm stream compared to all other streams. Total phosphorous, total dissolved phosphorous, and total nitrogen loads for measured water yields were elevated in the agroforest and young oil palm sites compared to the forest site. Our results indicate that oil palm plantation land use alters tropical stream temperature, metabolism, nutrient loads, and sediment loads; moreover, these conditions appear to persist for ≥ 15 years. We discuss the implications of these findings for local human communities and ecosystems.

  5. Headwater effects on downstream waters: Legal perspectives, science needs, and assessment approaches

    EPA Science Inventory

    Headwater streams make up at least 53% of total stream length in the US. Although these systems are of interest for their own sake, there has recently been significant focus on how headwater streams contribute to downstream waters. This has resulted in part from recent legal op...

  6. The impact of agricultural runoff on stream benthos in Hong Kong, China.

    PubMed

    Neumann, Michael; Dudgeon, David

    2002-07-01

    We investigated three small streams in the New Territories of Hong Kong, China. In each stream, we compared the benthic macroinvertebrate fauna of one site immediately upstream of an area of agricultural land (market gardening) with a second site immediately downstream. Each pair of sites was < 300 m apart. Samples were taken at the end of the dry season (March 2000) and again (April 2000) just after heavy rainfall had caused runoff from the fields. The total number of taxa at the downstream sites was the same as that in the upstream sites in March. In April, the total taxon richness was lower at the downstream localities although this difference was statistically significant in only one stream. The acute toxic effect of runoff became clearer when focusing on the group of sensitive benthic fauna. The grouping was done by ranking the relatively physiological tolerance to organotoxins following the relevant literature (Bull. Environ. Contam. Toxicol. 67 (2001) 360). All streams showed a significant downstream decrease in the number of sensitive taxa in April, while in two of three streams the number of relatively tolerant taxa increased. Ordination (by n-MDS) confirmed this pattern. It revealed a marked temporal trend in all streams resulting from a decrease of sensitive taxa downstream that was not apparent at the upstream sites. The size of the observed effects varied among streams, and may have reflected differences in the composition of the agricultural runoff.

  7. Phosphorus dynamics in lowland streams as a response to climatic, hydrological and agricultural land use gradients

    NASA Astrophysics Data System (ADS)

    Goyenola, G.; Meerhoff, M.; Teixeira-de Mello, F.; González-Bergonzoni, I.; Graeber, D.; Fosalba, C.; Vidal, N.; Mazzeo, N.; Ovesen, N. B.; Jeppesen, E.; Kronvang, B.

    2015-03-01

    Climate and hydrology are relevant control factors for determining the timing and amount of nutrient losses from agricultural fields to freshwaters. In this study, we evaluated the effect of agricultural intensification on the concentrations, dynamics and export of phosphorus (P) in streams in two contrasting climate and hydrological regimes (temperate Denmark and subtropical Uruguay). We applied two alternative nutrient sampling programmes (high frequency composite sampling and low frequency instantaneous-grab sampling) and three alternative methods to estimate exported P from the catchments. A source apportionment model was applied to evaluate the contribution derived from point and diffuse sources in all four catchments studied. Climatic and hydrological characteristics of catchments expressed as flow responsiveness (flashiness), exerted control on catchment and stream TP dynamics, having consequences that were more significant than the outcome of different TP monitoring and export estimation strategies. The impact of intensification of agriculture differed between the two contrasting climate zones. Intensification had a significant impact on subtropical climate with much higher total (as high as 4436 μg P L-1), particulate, dissolved and reactive soluble P concentrations and higher P export (as high as 5.20 kg P ha-1 year-1). However, we did not find an increased contribution of particulate P to total P as consequence of higher stream flashiness and intensification of agriculture. The high P concentrations at low flow and predominance of dissolved P in subtropical streams actually exacerbate the environmental and sanitary risks associated with eutrophication. In the other hand, temperate intensively farmed stream had lower TP than extensively farmed stream. Our results suggest that the lack of environmental regulations of agricultural production has more severe consequences on water quality, than climatic and hydrological differences between the analysed

  8. Understanding the controls on deposited fine sediment in the streams of agricultural catchments.

    PubMed

    Naden, P S; Murphy, J F; Old, G H; Newman, J; Scarlett, P; Harman, M; Duerdoth, C P; Hawczak, A; Pretty, J L; Arnold, A; Laizé, C; Hornby, D D; Collins, A L; Sear, D A; Jones, J I

    2016-03-15

    Excessive sediment pressure on aquatic habitats is of global concern. A unique dataset, comprising instantaneous measurements of deposited fine sediment in 230 agricultural streams across England and Wales, was analysed in relation to 20 potential explanatory catchment and channel variables. The most effective explanatory variable for the amount of deposited sediment was found to be stream power, calculated for bankfull flow and used to index the capacity of the stream to transport sediment. Both stream power and velocity category were highly significant (p ≪ 0.001), explaining some 57% variation in total fine sediment mass. Modelled sediment pressure, predominantly from agriculture, was marginally significant (p<0.05) and explained a further 1% variation. The relationship was slightly stronger for erosional zones, providing 62% explanation overall. In the case of the deposited surface drape, stream power was again found to be the most effective explanatory variable (p<0.001) but velocity category, baseflow index and modelled sediment pressure were all significant (p<0.01); each provided an additional 2% explanation to an overall 50%. It is suggested that, in general, the study sites were transport-limited and the majority of stream beds were saturated by fine sediment. For sites below saturation, the upper envelope of measured fine sediment mass increased with modelled sediment pressure. The practical implications of these findings are that (i) targets for fine sediment loads need to take into account the ability of streams to transport/retain fine sediment, and (ii) where agricultural mitigation measures are implemented to reduce delivery of sediment, river management to mobilise/remove fines may also be needed in order to effect an improvement in ecological status in cases where streams are already saturated with fines and unlikely to self-cleanse.

  9. Occurrence, leaching, and degradation of Cry1Ab protein from transgenic maize detritus in agricultural streams

    DOE PAGES

    Griffiths, Natalie A.; Tank, Jennifer L.; Royer, Todd V.; ...

    2017-03-15

    The insecticidal Cry1Ab protein expressed by transgenic (Bt) maize can enter adjacent water bodies via multiple pathways, but its fate in stream ecosystems is not as well studied as in terrestrial systems. In this study, we used a combination of field sampling and laboratory experiments to examine the occurrence, leaching, and degradation of soluble Cry1Ab protein derived from Bt maize in agricultural streams. We surveyed 11 agricultural streams in northwestern Indiana, USA, on 6 dates that encompassed the growing season, crop harvest, and snowmelt/spring flooding, and detected Cry1Ab protein in the water column and in flowing subsurface tile drains atmore » concentrations of 3–60 ng/L. In a series of laboratory experiments, submerged Bt maize leaves leached Cry1Ab into stream water with 1% of the protein remaining in leaves after 70 d. Laboratory experiments suggested that dissolved Cry1Ab protein degraded rapidly in microcosms containing water-column microorganisms, and light did not enhance breakdown by stimulating assimilatory uptake of the protein by autotrophs. Here, the common detection of Cry1Ab protein in streams sampled across an agricultural landscape, combined with laboratory studies showing rapid leaching and degradation, suggests that Cry1Ab may be pseudo-persistent at the watershed scale due to the multiple input pathways from the surrounding terrestrial environment.« less

  10. Contrasting Pesticide Occurrence in Urban and Agricultural Streams in the Midwestern United States

    NASA Astrophysics Data System (ADS)

    Mahler, B. J.; Van Metre, P. C.; Sandstrom, M. W.; Nowell, L. H.; Frey, J. W.; Hladik, M.; Gilliom, R. W.

    2014-12-01

    Pesticides are known to degrade stream ecosystems in agricultural and urban settings. Occurrence, seasonal timing, and predicted toxicity of pesticides in these two settings, however, can vary greatly. In 2013, the U.S. Geological Survey and the U.S. Environmental Protection Agency characterized water-quality stressors—contaminants, nutrients, and sediment—and ecological conditions in 100 streams across the Midwestern U.S. Water samples were collected weekly from May through July and sediment and ecology were sampled once near the end of the water-sampling period. Water samples were analyzed for about 240 pesticides and pesticide degradates and sediment samples were analyzed for about 120 pesticides and degradates. The spatial and temporal distribution of detected compounds and the pesticide toxicity index (PTI) of compound mixtures indicate important differences in pesticide occurrence between agricultural and urban settings. Although higher pesticide concentrations generally are found in agricultural settings, the more frequent occurrence of insecticides in urban settings can lead to higher PTI scores in some urban streams than in agricultural streams.

  11. Floodplain restoration enhances denitrification and reach-scale nitrogen removal in an agricultural stream

    EPA Science Inventory

    Streams of the agricultural Midwest export large quantities of nitrogen, which impairs downstream water quality, most notably in the Gulf of Mexico. The two-stage ditch is a novel restoration practice, in which floodplains are constructed alongside channelized ditches. During hi...

  12. Comparison of SWAT Predictions with Stream Biological Integrity Observations in an Agricultural Watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The SWAT model is calibrated with USGS data for an agricultural watershed located on the Eastern Shore of Maryland. Model predictions of runoff, sediment, nitrogen and phosphorus amounts, at the outlet of sub-watersheds, are compared to measurements of stream biological integrity conducted throughou...

  13. Evaluation of agricultural best-management practices in the Conestoga River headwaters, Pennsylvania; hydrology of a small carbonate site near Ephrata, Pennsylvania, prior to implementation of nutrient management

    USGS Publications Warehouse

    Koerkle, E.H.; Hall, D.W.; Risser, D.W.; Lietman, P.L.; Chichester, D.C.

    1997-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Department of Agriculture and Pennsylvania Department of Environmental Protection, investigated the effects of agricultural best-management practices on water quality in the Conestoga River headwaters watershed. This report describes environmental factors and the surface-water and ground-water quality of one 47.5-acre field site, Field-Site 2, from October 1984 through September 1986, prior to implementation of nutrient management. The site is partially terraced agricultural cropland underlain by carbonate rock. Twenty-seven acres are terraced, pipe-drained, and are under no-till cultivation. The remaining acreage is under minimum-till cultivation. Corn is the primary crop. The average annual rate of fertilization at the site was 480 pounds per acre of nitrogen and 110 pounds per acre of phosphorus. An unconfined limestone and dolomitic aquifer underlies the site, Depth to bedrock ranges from 5 to 30 feet below land surface. Estimated specific yields range from 0.05 to 0.10, specific capacities of wells range from less than 1 to about 20 gallons per minute per foot of drawdown, and estimates of transmissivities range from 10 to 10,000 square feet per day. Average ground-water recharge was estimated to be about 23 inches per year. The specific capacity and transmissivity data indicate that two aquifer regimes are present at the site. Wells drilled into dolomites in the eastern part of the site have larger specific capacities (averaging 20 gallons per minute per foot of drawdown) relative to specific capacities (averaging less than 1 gallon per minute per foot of drawdown) of wells drilled into limestones in the western part of the site. Median concentrations of soil-soluble nitrate and soluble phosphorus in the top 4 feet of silt- or silty-clay-loam soil ranged from 177 to 329 and 8.5 to 35 pounds per acre, respectively. Measured runoff from the pipe-drained terraces ranged from 10 to 48,000 cubic feet and was

  14. Comparison of Hydrologic and Water-Quality Characteristics of Two Native Tallgrass Prairie Streams with Agricultural Streams in Missouri and Kansas

    USGS Publications Warehouse

    Heimann, David C.

    2009-01-01

    This report presents the results of a study by the U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources, to analyze and compare hydrologic and water-quality characteristics of tallgrass prairie and agricultural basins located within the historical distribution of tallgrass prairie in Missouri and Kansas. Streamflow and water-quality data from two remnant, tallgrass prairie basins (East Drywood Creek at Prairie State Park, Missouri, and Kings Creek near Manhattan, Kansas) were compared to similar data from agricultural basins in Missouri and Kansas. Prairie streams, especially Kings Creek in eastern Kansas, received a higher percentage of base flow and a lower percentage of direct runoff than similar-sized agricultural streams in the region. A larger contribution of direct runoff from the agricultural streams made them much flashier than prairie streams. During 22 years of record, the Kings Creek base-flow component averaged 66 percent of total flow, but base flow was only 16 to 26 percent of flows at agricultural sites of various record periods. The large base-flow component likely is the result of greater infiltration of precipitation in prairie soils and the resulting greater contribution of groundwater to streamflow. The 1- and 3-day annual maximum flows were significantly greater at three agricultural sites than at Kings Creek. The effects of flashier agricultural streams on native aquatic biota are unknown, but may be an important factor in the sustainability of some native aquatic species. There were no significant differences in the distribution of dissolved-oxygen concentrations at prairie and agricultural sites, and some samples from most sites fell below the 5 milligrams per liter Missouri and Kansas standard for the protection of aquatic life. More than 10 percent of samples from the East Drywood Creek prairie stream were less than this standard. These data indicate low dissolved-oxygen concentrations during summer low

  15. Ecosystem Services Derived from Headwater Catchments

    EPA Science Inventory

    We used data from the USEPA’s wadeable streams assessment (WSA), US Forest Service’s forest inventory and analysis (FIA), and select USFS experimental forests (EF) to investigate potential ecosystems services derived from headwater catchments. C, N, and P inputs to these catchmen...

  16. Implications of Transgenic Corn Cultivation on the Ecology of Agricultural Streams

    NASA Astrophysics Data System (ADS)

    Vantull, L.; Swan, C.

    2005-05-01

    Corn has been genetically-modified by introducing a gene that codes for a toxic protein from a bacterium, Bacillus thuringiensis (Bt), into corn DNA. Genetically-modified crops provide internal resistance to herbivorous pests like the European Corn Borer (Ostrina nubilalis). With the use of transgenic crops on the rise, research is being done to consider its environmental effects on non-target taxa and ecosystems. Stream ecosystems occupy topographic low points in the landscape and thus are affected by agricultural land use. In many temperate streams, the main energy source is from terrestrial organic detritus, mostly in the form of dead leaves and wood, delivered via wind or natural leaf fall. Stream insects consume this material, contributing to organic matter breakdown and creating biomass for predators. With the heightened practice of no-till agriculture, crop detritus remaining on fields as a by-product of harvesting has been documented to enter adjacent streams. Given insect larvae are critical to the transformation of energy from detritus to higher trophic levels, we explored the implications of detritus containing Bt on both insect performance and litter decay in six streams. The presence of Bt in senesced corn leaf litter resulted in significant reductions in both insect feeding rate and organic matter breakdown. Furthermore, colonization of corn litter containing Bt by detritivorous insects was significantly reduced when compared to non-Bt isoline litter controls. We conclude that detritus generated from harvesting transgenic corn negatively impacts insect feeding behavior and colonization dynamics, and may contribute substantially to the reduction of organic matter breakdown rates in agricultural streams.

  17. Assessment of in-stream phosphorus dynamics in agricultural drainage ditches.

    PubMed

    Smith, D R

    2009-06-01

    The intensive agricultural systems in the Midwestern United States can enrich surface waters with nutrients. Agricultural drainage ditches serve as the first and second order streams throughout much of this region, as well as other highly productive agricultural areas in humid regions throughout the world. This project was conducted to evaluate in-stream processing of soluble P (SP) in agricultural drainage ditches. Soluble P injection studies were conducted at seven sites along three drainage ditches (298 to 4300 ha drainage area), and one site on a third-order stream that receives the discharge from the agricultural ditches (19,000 ha drainage area) by increasing the SP concentration in the ditch water by approximately 0.25 mg L(-1). Sediments collected from smaller watersheds contained greater amounts of Mehlich 3 and exchangeable P (ExP), silt and clay size particles, and organic matter. Phosphorus uptake lengths (S(net)) ranged from 40 to 1900 m, and SP uptake rates (U) ranged from 0.4 to 52 mg m(-2) h(-1). Phosphorus S(net) was correlated with ditch geomorphological (i.e. width) and sediment properties (i.e. organic matter, ExP, and equilibrium P concentration; r(2)=1.00, P<0.001), indirect drainage in the watershed (r(2)=0.92, P<0.001), and the amount of small grains, forest, urban area, alfalfa and corn (r(2)=1.00, P<0.0001). Agricultural drainage ditches actively process nutrients and could potentially be managed to optimize this processing to minimize SP export from these landscapes.

  18. Retention and Migration of Fine Organic Particles within an Agricultural Stream: Toenepi, Waikato, New Zealand

    NASA Astrophysics Data System (ADS)

    Drummond, J. D.; Davies-Colley, R.; Stott, R.; Sukias, J.; Nagels, J.; Sharp, A.; Packman, A. I.

    2013-12-01

    Fine organic particle dynamics are important to stream biogeochemistry, ecology, and transport of contaminant microbes. These particles migrate downstream through a series of deposition and resuspension events, which results in a wide range of residence times. This retention influences biogeochemical processing and in-stream stores of contaminant microbes that may mobilize during flood events and present a hazard to downstream uses such as water supplies and recreation. We are conducting studies to gain insights into organic particle dynamics in streams, with a campaign of experiments and modeling. The results should improve understanding of nutrient (C, N, P) spiraling and fine sediment movement in streams, and have particular application to microbial hazards. We directly measure microbial transport by including the indicator organism, E. coli, as a tracer, which is compared to a fluorescent inert particle tracer and conservative solute to gain insight on both microbial ecology and waterborne disease transmission. We developed a stochastic model to describe the transport and retention of fine suspended particles in rivers, including advective delivery of particles to the streambed, transport through porewaters, and reversible filtration within the streambed. Because fine particles are only episodically transported in streams, with intervening periods at rest in the bed, this transport process violates conventional advection-dispersion assumptions. Instead we adopt a stochastic mobile-immobile model formulation to describe fine particle transport. We apply this model to measurements of particle transport from multiple tracer experiments in an agricultural stream in the Waikato dairy region of New Zealand, and use the model to improve interpretation of baseflow particle dynamics. Our results show the importance of the benthic and hyporheic regions and in-stream vegetation as a reservoir for fine organic particles in streams.

  19. Effects of multi-scale environmental characteristics on agricultural stream biota in eastern Wisconsin

    USGS Publications Warehouse

    Fitzpatrick, F.A.; Scudder, B.C.; Lenz, B.N.; Sullivan, D.J.

    2001-01-01

    The U.S. Geological Survey examined 25 agricultural streams in eastern Wisconsin to determine relations between fish, invertebrate, and algal metrics and multiple spatial scales of land cover, geologic setting, hydrologic, aquatic habitat, and water chemistry data. Spearman correlation and redundancy analyses were used to examine relations among biotic metrics and environmental characteristics. Riparian vegetation, geologic, and hydrologic conditions affected the response of biotic metrics to watershed agricultural land cover but the relations were aquatic assemblage dependent. It was difficult to separate the interrelated effects of geologic setting, watershed and buffer land cover, and base flow. Watershed and buffer land cover, geologic setting, reach riparian vegetation width, and stream size affected the fish IBI, invertebrate diversity, diatom IBI, and number of algal taxa; however, the invertebrate FBI, percentage of EPT, and the diatom pollution index were more influenced by nutrient concentrations and flow variability. Fish IBI scores seemed most sensitive to land cover in the entire stream network buffer, more so than watershed-scale land cover and segment or reach riparian vegetation width. All but one stream with more than approximately 10 percent buffer agriculture had fish IBI scores of fair or poor. In general, the invertebrate and algal metrics used in this study were not as sensitive to land cover effects as fish metrics. Some of the reach-scale characteristics, such as width/depth ratios, velocity, and bank stability, could be related to watershed influences of both land cover and geologic setting. The Wisconsin habitat index was related to watershed geologic setting, watershed and buffer land cover, riparian vegetation width, and base flow, and appeared to be a good indicator of stream quality. Results from this study emphasize the value of using more than one or two biotic metrics to assess water quality and the importance of environmental

  20. Sediment denitrification and nitrification is enhanced by the presence of macrophytes in a restored agricultural stream, Black Earth Creek, WI USA

    EPA Science Inventory

    Restoration of habitats that support microbial processing can enhance nitrate removal in agricultural streams. Macrophytes are common both in-stream and in the wetted fringe of agricultural stream systems, but are often removed in restoration to increase stream velocity or stabil...

  1. Climate warming and agricultural stressors interact to determine stream macroinvertebrate community dynamics.

    PubMed

    Piggott, Jeremy J; Townsend, Colin R; Matthaei, Christoph D

    2015-05-01

    Global climate change is likely to modify the ecological consequences of currently acting stressors, but potentially important interactions between climate warming and land-use related stressors remain largely unknown. Agriculture affects streams and rivers worldwide, including via nutrient enrichment and increased fine sediment input. We manipulated nutrients (simulating agricultural run-off) and deposited fine sediment (simulating agricultural erosion) (two levels each) and water temperature (eight levels, 0-6°C above ambient) simultaneously in 128 streamside mesocosms to determine the individual and combined effects of the three stressors on macroinvertebrate community dynamics (community composition and body size structure of benthic, drift and insect emergence assemblages). All three stressors had pervasive individual effects, but in combination often produced additive or antagonistic outcomes. Changes in benthic community composition showed a complex interplay among habitat quality (with or without sediment), resource availability (with or without nutrient enrichment) and the behavioural/physiological tendency to drift or emerge as temperature rose. The presence of sediment and raised temperature both resulted in a community of smaller organisms. Deposited fine sediment strongly increased the propensity to drift. Stressor effects were most prominent in the benthic assemblage, frequently reflected by opposite patterns in individuals quitting the benthos (in terms of their propensity to drift or emerge). Of particular importance is that community measures of stream health routinely used around the world (taxon richness, EPT richness and diversity) all showed complex three-way interactions, with either a consistently stronger temperature response or a reversal of its direction when one or both agricultural stressors were also in operation. The negative effects of added fine sediment, which were often stronger at raised temperatures, suggest that streams already

  2. Influence of eastern hemlock (Tsuga canadensis L.) on fish community structure and function in headwater streams of the Delaware River basin

    USGS Publications Warehouse

    Ross, R.M.; Bennett, R.M.; Snyder, C.D.; Young, J.A.; Smith, D.R.; Lemarie, D.P.

    2003-01-01

    Hemlock (Tsuga canadensis) forest of the eastern U.S. are in decline due to invasion by the exotic insect hemlock woolly adelgid (Adelges tsugae). Aquatic biodiversity in hemlock ecosystems has not been documented; thus the true impact of the infestation cannot be assessed. We compared ichthyofaunal assemblages and trophic structure of streams draining hemlock and hardwood forests by sampling first- and second-order streams draining 14 paired hemlock and hardwood stands during base flows in July 1997 at the Delaware Water Gap National Recreation Area of Pennsylvania and New Jersey. Over 1400 fish of 15 species and 7 families were collected, but hemlock and hardwood streams individually harbored only one to four species. Brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) were two to three times as prevalent in hemlock than hardwood streams. Insectivorous fishes occurred in significantly higher proportion in streams of hardwood (0.90) than hemlock (0.46) stands, while piscivores occurred more often in hemlock (0.85) than hardwood (0.54) stands. Functional (trophic) diversity of fishes in hemlock and second-order streams was numerically greater than that of hardwood and first-order streams. Species composition also differed by stream order and terrain type. Biodiversity is threatened at several levels within hemlock ecosystems at risk to the hemlock woolly adelgid in eastern U.S. forests.

  3. Stream sediment sources in midwest agricultural basins with land retirement along channel

    USGS Publications Warehouse

    Williamson, Tanja N.; Christensen, Victoria G.; Richardson, William B.; Frey, Jeffrey W.; Gellis, Allen C.; Kieta, K. A.; Fitzpatrick, Faith A.

    2014-01-01

    Documenting the effects of agricultural land retirement on stream-sediment sources is critical to identifying management practices that improve water quality and aquatic habitat. Particularly difficult to quantify are the effects from conservation easements that commonly are discontinuous along channelized streams and ditches throughout the agricultural midwestern United States. Our hypotheses were that sediment from cropland, retired land, stream banks, and roads would be discernible using isotopic and elemental concentrations and that source contributions would vary with land retirement distribution along tributaries of West Fork Beaver Creek in Minnesota. Channel-bed and suspended sediment were sampled at nine locations and compared with local source samples by using linear discriminant analysis and a four-source mixing model that evaluated seven tracers: In, P, total C, Be, Tl, Th, and Ti. The proportion of sediment sources differed significantly between suspended and channel-bed sediment. Retired land contributed to channel-bed sediment but was not discernible as a source of suspended sediment, suggesting that retired-land material was not mobilized during high-flow conditions. Stream banks were a large contributor to suspended sediment; however, the percentage of stream-bank sediment in the channel bed was lower in basins with more continuous retired land along the riparian corridor. Cropland sediments had the highest P concentrations; basins with the highest cropland-sediment contributions also had the highest P concentrations. Along stream reaches with retired land, there was a lower proportion of cropland material in suspended sediment relative to sites that had almost no land retirement, indicating less movement of nutrients and sediment from cropland to the channel as a result of land retirement.

  4. Habitat loss drives threshold response of benthic invertebrate communities to deposited sediment in agricultural streams.

    PubMed

    Burdon, Francis J; McIntosh, Angus R; Harding, Jon S

    2013-07-01

    Agricultural land uses can impact stream ecosystems by reducing suitable habitat, altering flows, and increasing inputs of diffuse pollutants including fine inorganic sediment (< 2 mm). These changes have been linked to altered community composition and declines in biodiversity. Determining the mechanisms driving stream biotic responses, particularly threshold impacts, has, however, proved elusive. To investigate a sediment threshold response by benthic invertebrates, an intensive survey of 30 agricultural streams was conducted along gradients of deposited sediment and dissolved nutrients. Partial redundancy analysis showed that invertebrate community composition changed significantly along the gradient of deposited fine sediment, whereas the effect of dissolved nitrate was weak. Pollution-sensitive invertebrates (%EPT, Ephemeroptera, Plecoptera, Trichoptera) demonstrated a strong nonlinear response to sediment, and change-point analysis indicated marked declines beyond a threshold of -20% fine sediment covering the streambed. Structural equation modeling indicated that decreased habitat availability (i.e., coarse substrate and associated interstices) was the key driver affecting pollution-sensitive invertebrates, with degraded riparian condition controlling resources through direct (e.g., inputs) and indirect (e.g., flow-mediated) effects on deposited sediment. The identification of specific effects thresholds and the underlying mechanisms (e.g., loss of habitat) driving these changes will assist managers in setting sediment criteria and standards to better guide stream monitoring and rehabilitation.

  5. Strontium isotope geochemistry of groundwaters and streams affected by agriculture, Locust Grove, MD

    USGS Publications Warehouse

    Böhlke, J.K.; Horan, M.

    2000-01-01

    The effects of agriculture on the isotope geochemistry of Sr were investigated in two small watersheds in the Atlantic coastal plain of Maryland. Stratified shallow oxic groundwaters in both watersheds contained a retrievable record of increasing recharge rates of chemicals including NO3/-, Cl, Mg, Ca and Sr that were correlated with increasing fertilizer use between about 1940 and 1990. The component of Sr associated with recent agricultural recharge was relatively radiogenic (87Sr/86Sr = 0.715) and it was overwhelming with respect to Sr acquired naturally by water-rock interactions in the oxidized, non-calcareous portion of the saturated zone. Agricultural groundwaters that penetrated relatively unoxidized calcareous glauconitic sediments at depth acquired an additional component of Sr from dissolution of early tertiary marine CaCO3 (87Sr/86Sr=0.708) while undergoing O2 reduction and denitrification. Ground-water discharge contained mixtures of waters of various ages and redox states. Two streams draining the area are considered to have higher 87Sr/86Sr ratios and NO3/- concentrations than they would in the absence of agriculture; however, the streams have consistently different 87Sr/86Sr ratios and NO3/- concentrations because the average depth to calcareous reducing (denitrifying) sediments in the local groundwater flow system was different in the two watersheds. The results of this study indicate that agriculture can alter significantly the isotope geochemistry of Sr in aquifers and streams and that the effects could vary depending on the types, sources and amounts of fertilizers added, the history of fertilizer use and groundwater residence times. (C) 2000 Elsevier Science Ltd.

  6. Non-indigenous bamboo along headwater streams of the Luquillo Mountains, Puerto Rico: Leaf fall, aquatic leaf decay and patterns of invasion

    USGS Publications Warehouse

    O'Connor, P. J.; Covich, A.P.; Scatena, F.N.; Loope, L.L.

    2000-01-01

    The introduction of bamboo to montane rain forests of the Luquillo Mountains, Puerto Rico in the 1930s and 1940s has led to present-day bamboo monocultures in numerous riparian areas. When a non-native species invades a riparian ecosystem, in-stream detritivores can be affected. Bamboo dynamics expected to influence stream communities in the Luquillo Experimental Forest (LEF) were examined. Based on current distributions, bamboo has spread down-stream at a rate of 8 m y-1. Mean growth rate of bamboo culms was 15.3 cm d-1. Leaf fall from bamboo stands exceeded that of native mixed-species forest by c. 30% over a 10-mo study. Bamboo leaves (k = -0.021), and leaves from another abundant riparian exotic, Syzygium jambos (Myrtaceae) (k = -0.018), decayed at relatively slow rates when submerged in streams in fine-mesh bags which excluded macro-invertebrate leaf processors. In a second study, with leaf processors present, bamboo decay rates remained unchanged (k = -0.021), while decay rates of S. jambos increased (k = -0.037). Elemental losses from bamboo leaves in streams were rapid, further suggesting a change in riparian zone/stream dynamics following bamboo invasion. As non-indigenous bamboos spread along Puerto Rico streams, they are likely to alter aquatic communities dependent on leaf input.

  7. Agricultural herbicide transport in a first-order intermittent stream, Nebraska, USA

    USGS Publications Warehouse

    Vogel, J.R.; Linard, J.I.

    2011-01-01

    The behavior of herbicides in surface waters is a function of many variables, including scale of the watershed, physical and chemical properties of the herbicide, physical and chemical properties of the soil, rainfall intensity, and time of year. In this study, the transport of 6 herbicides and 12 herbicide degradates was examined during the 2004 growing season in an intermediate-scale agricultural watershed (146 ha) that is drained by a first-order intermittent stream, and the mass load for each herbicide in the stream was estimated. The herbicide load during the first week of storm events after application ranged from 17% of annual load for trifluralin to 84% of annual load for acetochlor. The maximum weekly herbicide load in the stream was generally within the first 3 weeks after application for those compounds that were applied within the watershed during 2004, and later for herbicides not applied within the watershed during 2004 but still detected in the stream. The apparent dominant mode of herbicide transport in the stream-determined by analysis amongst herbicide and conservative ion concentrations at different points in the hydrograph and in base flow samples-was either overland runoff or shallow subsurface flow, depending on the elapsed time after application and type of herbicide. The load as a percentage of use (LAPU) for the parent compounds in this study was similar to literature values for those compounds applied by the farmer within the watershed, but smaller for those herbicides that had rainfall as their only source within the watershed.

  8. Baseline Q-values for streams in intensive agricultural catchments in Ireland

    NASA Astrophysics Data System (ADS)

    Melland, Alice; Jordan, Phil; Wall, David; Mellander, Per-Erik; Mechan, Sarah; Shortle, Ger

    2010-05-01

    The effectiveness of regulations introduced in Ireland in 2006 in response to the European Union Nitrates Directives for minimising nutrient loss to waterways from farms is being studied by Teagasc, the Irish Agriculture and Food Development Authority as part of an Agricultural Catchments Programme from 2008 - 2011. The regulations in Ireland require that during winter, green cover is established and maintained on arable farms, manure is stored and not spread, ploughing is not conducted and that chemical fertiliser is not spread. The regulations also require buffer zones between fields and water courses when applying organic or chemical fertilisers and that nutrient application rates and timing match crop requirements. An upper limit for livestock manure loading of 170 kg ha-1 organic N each year is also set. The biophysical research component of the Agricultural Catchments Programme is focussed on quantifying nutrient source availability, surface and subsurface transport pathways and stream chemical water quality. A baseline description of stream ecological quality was also sought. Stream ecology was measured in autumn 2009 at 3-5 locations within four surface water catchments and at the spring emergence of a catchment underlain by karst limestone. Landuse in each catchment is dominated by medium to high intensity grassland or cereal farming and annual average rainfall ranges from 900 - 1200 mm. Surveys were conducted in 1st to 3rd order streams throughout each catchment at locations which had minimal observed point source inputs for 100m upstream, incomplete shade, a hard streambed substrate and riffle conditions suitable for the sampling methods. Benthic macroinvertebrates were identified and quantified and used to calculate the biological indices Small Stream Risk Score, Q-value, Biological Monitoring Working Party (BMWP), Average Score Per Taxa (ASPT) and EQR (Observed Q-value/Reference Q-value). Diatom community assemblages were identified from samples

  9. Environmental setting of benchmark streams in agricultural areas of eastern Wisconsin

    USGS Publications Warehouse

    Rheaume, S.J.; Stewart, J.S.; Lenz, B.N.

    1996-01-01

    Differences in land use/land cover, and riparian vegetation and instream habitat characteristics are presented. Summaries of field measurements of water temperature, pH, specific conductance and concentrations of dissolved oxygen, total organic plus ammonia nitrogen, dissolved ammonium, nitrate plus nitrte as nitrogen, total phosphorus, dissolved orthophosphate, and atrazine are listed. Concentrations of dissolved oxygen for the sampled streams ranged from 6 A to 14.3 and met the standards set by the Wisconsin Department of Natural Resources (WDNR) for supporting fish and aquatic life. Specific conductance ranged from 98 to 753 u,Scm with values highest in RHU's 1 and 3, where streams are underlain by carbonate bedrock. Median pH did not vary greatly among the four RHU's and ranged from 6.7 to 8.8 also meeting the WDNR standards. Concentrations of total organic plus ammonia nitrogen, dissolved ammonium, total phosphorus, and dissolved orthophosphate show little variation between streams and are generally low, compared to concentrations measured in agriculturally-affected streams in the same RHU's during the same sampling period. Concentrations of the most commonly used pesticide in the study unit, atrazine, were low in all streams, and most concentrations were below trn 0.1 u,g/L detection limit. Riparian vegetation for the benchmark streams were characterized by lowland species of the native plant communities described by John T. Curtis in the "Vegetation of Wisconsin." Based on the environmental setting and water-quality information collected to date, these streams appear to show minimal adverse effects from human activity.

  10. Annual agricultural pesticide use for Midwest Stream-Quality Assessment, 2012-13

    USGS Publications Warehouse

    Baker, Nancy T.; Stone, Wesley W.

    2014-01-01

    This report provides estimates of annual agricultural use of 190 pesticide compounds for counties and selected watersheds of Midwestern States for 2012 and 2013 compiled for subsequent analysis by the National Water-Quality Assessment Program, Midwest Stream-Quality Assessment (MSQA). One of the goals of MSQA is to characterize contaminants at perennial-stream sites throughout the Corn Belt. Evaluating pesticide inputs from agricultural sources will aid in that characterization. Crop acres for selected Midwestern crops were obtained from the Cropland Data Layer of the U.S. Department of Agriculture’s National Agricultural Statistics Service and used in conjunction with GfK Kynetec, Inc. proprietary Crop Reporting District-level pesticide-use data to estimate pesticide use for counties and watersheds. Estimated pesticide use (EPest) values were calculated by using both the “EPest-high” and “EPest-low” methods, the distinction being that there are more counties with estimated pesticide use for EPest-high compared to EPest-low, owing to differing assumptions about missing survey data. County-level and watershed-level estimates of annual agricultural pesticide use are provided as downloadable, tab-delimited files for both EPest-high and Epest-low. Summary graphs of MSQA watershed-level pesticide use for selected crops are also provided.

  11. Fish communities of benchmark streams in agricultural areas of eastern Wisconsin

    USGS Publications Warehouse

    Sullivan, D.J.; Peterson, E.M.

    1997-01-01

    Fish communities were surveyed at 20 stream sites in agricultural areas in eastern Wisconsin in 1993 and 1995 as part of the National Water-Quality Assessment (NAWQA) Program. These streams, designated "benchmark streams," were selected for study because of their potential use as regional references for healthy streams in agricultural areas, based on aquatic communities, habitat, and water chemistry. The agricultural benchmark streams were selected from four physical settings, or relatively homogeneous units (RHU's), that differ in bedrock type, texture of surficial deposits, and land use. Additional data were collected along with the fish-community data, including measures of habitat, water chemistry, and population surveys of algae and benthic invertebrates. Of the 20 sites, 19 are classified as trout (salmonid) streams. Fish species that require cold or cool water were the most commonly collected. At least one species of trout was collected at 18 sites, and trout were the most abundant species at 13 sites. The species with the greatest collective abundance, and collected at 18 of the 20 sites, were mottled sculpin (Cottus bairdi), a coldwater species. The next most abundant species were brown trout (Salmo trutta), followed by brook trout (Salvelinusfontinalis), creek chub (Semotilus atromaculatus), and longnose dace (Rhinichthys cataractae). In all, 31 species of fish were collected. The number of species per stream ranged from 2 to 14, and the number of individuals collected ranged from 19 to 264. According to Index of Biotic Integrity (IBI) scores, 5 sites were rated excellent, 10 sites rated good, 4 rated fair, and 1 rated poor. The ratings of the five sites in the fair to poor range were low for various reasons. Two sites appeared to have more warmwater species than was ideal for a high-quality coldwater stream. One was sampled during high flow and the results may not be valid for periods of normal flow; the other may have been populated by migrating

  12. Pyrethroid insecticides in bed sediments from urban and agricultural streams across the United States

    USGS Publications Warehouse

    Hladik, Michelle L.; Kuivila, Kathryn M.

    2012-01-01

    Pyrethroid insecticides are hydrophobic compounds that partition to streambed sediments and have been shown to cause toxicity to non-target organisms; their occurrence is well documented in parts of California, but there have been limited studies in other urban and agricultural areas across the United States. To broaden geographic understanding of pyrethroid distributions, bed sediment samples were collected and analyzed from 36 streams in 25 states, with about 2/3 of the sites in urban areas and 1/3 in agricultural areas. At least one pyrethroid (of the 14 included in the analysis) was detected in 78% of samples. Seven pyrethroids were detected in one or more samples. Bifenthrin was the most frequently detected (58% of samples), followed by permethrin (31%), resmethrin (17%), and cyfluthrin (14%). The other three detected pyrethroids (cyhalothrin, cypermethrin and delta/tralomethrin) were found in two or fewer of the samples. Concentrations ranged from 0.3 to 180 ng g-1 dry weight. The number of pyrethroids detected were higher in the urban samples than in the agricultural samples, but the highest concentrations of individual pyrethroids were split between urban and agricultural sites. The pyrethroids detected in the agricultural areas generally followed use patterns. Predicted toxicity was greater for urban areas and attributed to bifenthrin, cyfluthrin and cypermethrin, while in agricultural areas the toxicity was mainly attributed to bifenthrin.

  13. Channel-reach morphology controls of headwater streams based in flysch geologic structures: An example from the Outer Western Carpathians, Czech Republic

    NASA Astrophysics Data System (ADS)

    Galia, Tomáš; Hradecký, Jan

    2014-07-01

    A detailed measurement of 93 channel reaches that were classified with an adjusted Montgomery-Buffington (1997) reach-scale system provided comprehensive information of approximately 9 at-a-reach parameters: the channel gradient, the bankfull width, the bankfull depth, d90, the percentage of resistant rocks in the bed sediment, the number of pieces of large woody debris, valley confinement, direct sediment inputs and the presence of fluvial accumulations in the stream channel. In addition, the quantified intensity of sediment transport (i.e. ratio between sediment supply and transport capacity in longitudinal stream profiles) during flood events has been estimated by the one-dimensional bedload transport model (TOMSED), which was validated in two local streams. The principal component analysis of the at-a-reach parameters did not reveal significant groups of channel-reach morphologies; thus, the selected parameters that exclude sediment transport dynamics within stream longitudinal profile cannot reliably distinguish or predict individual channel reach morphologies. Nevertheless, the channel gradient represented the most significant single explanatory variable for stepped-bed morphologies. The addition of bedload transport parameters demonstrated that limited sediment supply streams and streams with limited transport capacities featured different successions of the channel reach morphologies in terms of the channel gradient and, subsequently, the fluvial continuity. The bedrock-cascades and step-pools were significant for the first case, whereas cascade and step-rapid morphology often occurred in higher sediment supply conditions.

  14. A Comparative Analysis of the Influence of Surface Mining on Hydrological and Geochemical Response of Selected Headwater Streams in the Elk Valley, British Columbia, Canada.

    NASA Astrophysics Data System (ADS)

    Carey, S. K.; Shatilla, N. J.; Szmudrowska, B.; Rastelli, J.; Wellen, C.

    2014-12-01

    Surface mining is a common method of accessing coal. Blasting of overburden rock allows access to mineable ore. In high-elevation environments, the removed overburden rock is deposited in adjacent valleys as waste rock spoils. As part of a multi-year R&D program examining the influence of surface mining on watershed hydrological and water quality responses in the Elk Valley, British Columbia, this study reports on how surface mining affects streamflow hydrological and geochemical response at four reference and four mine-influenced catchments. The hydrology of this environment is dominated by snowmelt and steep topographic gradients. Flows were attenuated in mine-influenced catchments, with spring freshet delayed and more muted responses to precipitation events observed. Dissolved ions were an order of magnitude greater in mine-influenced streams, with more dilution-based responses to flows compared with chemostatic behavior observed in reference streams. Stable isotope signatures in stream water suggested that in both mine-influenced and reference watersheds, stream water was derived from well mixed groundwater as annual variability of stream isotope signatures was dampened compared with precipitation signatures. However, deflection of stream isotopes in response to precipitation were more apparent in reference watersheds. As a group, mine influenced catchments had a heavier isotope signature than reference watersheds, suggesting an enhanced influence of rainfall on recharge. Transit time distributions indicate existing waste rock spoils increase the average time water takes to move through the catchment.

  15. RELATIONSIPS BETWEEN AQUATIC INVERTEBRATE ASSEMBLAGES AND REACH AND LANDSCAPE ATTRIBUTES ON WADEABLE, WILLAMETTE VALLEY STREAMS IN AGRICULTURAL WATERSHEDS

    EPA Science Inventory

    In summer 1997, we sampled reaches in 24 wadeable, Willamette Valley ecoregion streams draining agriculturally-infiuenced watersheds. Within these reaches, physical habitat, water chemistry, aquatic invertebrate and fish data and samples were collected. Low-level air photos were ...

  16. Impacts of converting low-intensity pastureland to high-intensity bioenergy cropland on the water quality of tropical streams in Brazil.

    PubMed

    Taniwaki, Ricardo Hideo; Cassiano, Carla Cristina; Filoso, Solange; Ferraz, Silvio Frosini de Barros; Camargo, Plínio Barbosa de; Martinelli, Luiz Antônio

    2017-04-15

    In Brazil, the cultivation of bioenergy crops is expanding at an accelerated rate. Most of this expansion has occurred over low-intensity pasture and is considered sustainable because it does not involve deforestation of natural vegetation. However, the impacts on the water quality of headwater streams are poorly understood, especially with regard to the influence of land use patterns in the watershed. In this study, we investigated the effects of land-use conversion on the water quality of streams draining sugarcane fields and examined whether the preservation of forested areas at the top of the headwaters would help mitigate the negative impacts of intensive agriculture. Water samples were collected in two paired catchments in southeastern Brazil, which is one of the largest sugarcane production regions in the world. Our results show significant differences in the water quality of streams predominantly draining the pasture or the sugarcane field. Several parameters commonly used to indicate water quality, such as the concentrations of nitrate and suspended solids, were significantly higher in the sugarcane than in the pasture stream. Differences in water quality between the streams draining predominantly pasture or sugarcane fields were accentuated during the wet season. The preservation of forests surrounding the headwater streams was associated with overall better water quality conditions, such as lower nitrate concentrations and temperature of the stream water. We concluded that forest conservation in the headwater agricultural catchments is an important factor preventing water quality degradation in tropical streams. Therefore, we strongly recommend the preservation of robust riparian forests in the headwaters of tropical watersheds with intensive agriculture. More studies on the effects of best agricultural practices in bioenergy crops can greatly improve our capacity to prevent the degradation of water quality in the tropical waterways as intensive

  17. Nitrogen concentrations and losses from agricultural streams in the Nordic and Baltic countries

    NASA Astrophysics Data System (ADS)

    Stålnacke, Per; Bechmann, Marianne; Blicher-Mathiesen, Gitte; Iital, Arvo; Kyllmar, Katarina; Koskiaho, Jari; Lagzdins, Ainis; Povilaitis, Arvydas

    2015-04-01

    Assessment of long-term trends is one of the key objectives in most national water quality monitoring programmes. It is for example essential that we know how long it can take to detect the response in agricultural streams to changes in agriculture and implemented measures, because such information is needed to allow environmental authorities and decision and policy makers to establish realistic goals. Thus, long-term monitoring data is the key to cover future management needs and demands such as implementation of various EU-Directives (e.g., WFD, the Nitrates Directive). This paper in a uniform fashion examines the levels and temporal trends of nitrogen concentrations and losses in streams draining agricultural catchment areas in the Nordic and Baltic countries. 35 catchments (range 0.1-33km2) in Norway (9), Denmark (5), Sweden (8), Finland (4), Estonia (3), Latvia (3) and Lithuania (3) were selected for the study. Most of these catchments are part of national water quality monitoring programmes and initially selected to represent the major crops, soil types and climatic conditions in each country. The longest time series where 23 years (1988-2010) while the shortest one was 10 years (2002-2011). The reasons for these identified trends and no-trends will be discussed during the oral presentation in relation to land use, agricultural management and implementation of mitigation measures. Furthermore, the difference in mean level concentrations and losses will be discussed in relation to differences in climate, land use and agricultural management Overall the results show that agricultural catchments in the Nordic and Baltic countries exhibit different levels of nitrogen concentrations and losses, with a large interannual variability in all catchments. For example, the overall range in annual long-term mean TN losses was 6-102 kg N ha-1. Nearly one third of the investigated agricultural catchments showed statistically significant downward trends in nitrogen losses or

  18. Projected stream water fluxes of NO3 and total organic carbon from the Storgama headwater catchment, Norway, under climate change and reduced acid deposition.

    PubMed

    de Wit, Heleen A; Wright, Richard F

    2008-02-01

    Fluctuations in the 20-year record of nitrate (NO3) and total organic carbon (TOC) concentrations and fluxes in runoff at the small headwater catchment Storgama, southern Norway, were related to climate and acid deposition. The long-term decline in NO3 related to reduced NO3 deposition and increased winter discharge, whereas the long-term increase in TOC related to reduced sulfur deposition. Multiple regression models describing long-term trends and seasonal variability in these records were used to project future concentrations given scenarios of climate change and acid deposition. All scenarios indicated reduced NO3 fluxes and increased TOC fluxes; the largest projected changes for the period 2071-2100 were -86% and +24%, respectively. Uncertainties are that the predicted future temperatures are considerably higher than the historical record. Also, nonlinear responses of ecosystem processes (nitrogen [N] mineralization) to temperature, N-enrichment of soils, and step-changes in environmental conditions may affect future leaching of carbon and N.

  19. Low transient storage and uptake efficiencies in seven agricultural streams: implications for nutrient demand

    USGS Publications Warehouse

    Sheibley, Rich W.; Duff, John H.; Tesoriero, Anthony J.

    2014-01-01

    We used mass load budgets, transient storage modeling, and nutrient spiraling metrics to characterize nitrate (NO3−), ammonium (NH4+), and inorganic phosphorus (SRP) demand in seven agricultural streams across the United States and to identify in-stream services that may control these conditions. Retention of one or all nutrients was observed in all but one stream, but demand for all nutrients was low relative to the mass in transport. Transient storage metrics (As/A, Fmed200, Tstr, and qs) correlated with NO3− retention but not NH4+ or SRP retention, suggesting in-stream services associated with transient storage and stream water residence time could influence reach-scale NO3− demand. However, because the fraction of median reach-scale travel time due to transient storage (Fmed200) was ≤1.2% across the sites, only a relatively small demand for NO3− could be generated by transient storage. In contrast, net uptake of nutrients from the water column calculated from nutrient spiraling metrics were not significant at any site because uptake lengths calculated from background nutrient concentrations were statistically insignificant and therefore much longer than the study reaches. These results suggest that low transient storage coupled with high surface water NO3− inputs have resulted in uptake efficiencies that are not sufficient to offset groundwater inputs of N. Nutrient retention has been linked to physical and hydrogeologic elements that drive flow through transient storage areas where residence time and biotic contact are maximized; however, our findings indicate that similar mechanisms are unable to generate a significant nutrient demand in these streams relative to the loads.

  20. Denitrification in Agriculturally Impacted Streams: Seasonal Changes in Structure and Function of the Bacterial Community

    PubMed Central

    Manis, Erin; Royer, Todd V.; Johnson, Laura T.; Leff, Laura G.

    2014-01-01

    Denitrifiers remove fixed nitrogen from aquatic environments and hydrologic conditions are one potential driver of denitrification rate and denitrifier community composition. In this study, two agriculturally impacted streams in the Sugar Creek watershed in Indiana, USA with different hydrologic regimes were examined; one stream is seasonally ephemeral because of its source (tile drainage), whereas the other stream has permanent flow. Additionally, a simulated flooding experiment was performed on the riparian benches of the ephemeral stream during a dry period. Denitrification activity was assayed using the chloramphenicol amended acetylene block method and bacterial communities were examined based on quantitative PCR and terminal restriction length polymorphisms of the nitrous oxide reductase (nosZ) and 16S rRNA genes. In the stream channel, hydrology had a substantial impact on denitrification rates, likely by significantly lowering water potential in sediments. Clear patterns in denitrification rates were observed among pre-drying, dry, and post-drying dates; however, a less clear scenario was apparent when analyzing bacterial community structure suggesting that denitrifier community structure and denitrification rate were not strongly coupled. This implies that the nature of the response to short-term hydrologic changes was physiological rather than increases in abundance of denitrifiers or changes in composition of the denitrifier community. Flooding of riparian bench soils had a short-term, transient effect on denitrification rate. Our results imply that brief flooding of riparian zones is unlikely to contribute substantially to removal of nitrate (NO3-) and that seasonal drying of stream channels has a negative impact on NO3- removal, particularly because of the time lag required for denitrification to rebound. This time lag is presumably attributable to the time required for the denitrifiers to respond physiologically rather than a change in abundance or

  1. Concentrations, loads, and yields of organic carbon in streams of agricultural watersheds

    USGS Publications Warehouse

    Kronholm, Scott; Capel, Paul

    2012-01-01

    Carbon is cycled to and from large reservoirs in the atmosphere, on land, and in the ocean. Movement of organic carbon from the terrestrial reservoir to the ocean plays an important role in the global cycling of carbon. The transition from natural to agricultural vegetation can change the storage and movement of organic carbon in and from a watershed. Samples were collected from 13 streams located in hydrologically and agriculturally diverse watersheds, to better understand the variability in the concentrations and loads of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the streams, and the variability in watershed yields. The overall annual median concentrations of DOC and POC were 4.9 (range: 2.1–6.8) and 1.1 (range: 0.4–3.8) mg C L−1, respectively. The mean DOC watershed yield (± SE) was 25 ± 6.8 kg C ha−1 yr−1. The yields of DOC from these agricultural watersheds were not substantially different than the DOC yield from naturally vegetated watersheds in equivalent biomes, but were at the low end of the range for most biomes. Total organic carbon (DOC + POC) annually exported from the agricultural watersheds was found to average 0.03% of the organic carbon that is contained in the labile plant matter and top 1 m of soil in the watershed. Since the total organic carbon exported from agricultural watersheds is a relatively small portion of the sequestered carbon within the watershed, there is the great potential to store additional carbon in plants and soils of the watershed, offsetting some anthropogenic CO2 emissions.

  2. Concentrations, loads, and yields of organic carbon in streams of agricultural watersheds.

    PubMed

    Kronholm, Scott; Capel, Paul

    2012-01-01

    Carbon is cycled to and from large reservoirs in the atmosphere, on land, and in the ocean. Movement of organic carbon from the terrestrial reservoir to the ocean plays an important role in the global cycling of carbon. The transition from natural to agricultural vegetation can change the storage and movement of organic carbon in and from a watershed. Samples were collected from 13 streams located in hydrologically and agriculturally diverse watersheds, to better understand the variability in the concentrations and loads of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the streams, and the variability in watershed yields. The overall annual median concentrations of DOC and POC were 4.9 (range: 2.1-6.8) and 1.1 (range: 0.4-3.8) mg C L, respectively. The mean DOC watershed yield (± SE) was 25 ± 6.8 kg C ha yr. The yields of DOC from these agricultural watersheds were not substantially different than the DOC yield from naturally vegetated watersheds in equivalent biomes, but were at the low end of the range for most biomes. Total organic carbon (DOC + POC) annually exported from the agricultural watersheds was found to average 0.03% of the organic carbon that is contained in the labile plant matter and top 1 m of soil in the watershed. Since the total organic carbon exported from agricultural watersheds is a relatively small portion of the sequestered carbon within the watershed, there is the great potential to store additional carbon in plants and soils of the watershed, offsetting some anthropogenic CO emissions.

  3. Reduction of stream sediment concentration by a riparian buffer: filtering of road runoff in disturbed headwater basins of montane mainland southeast Asia.

    PubMed

    Ziegler, Alan D; Negishi, Junjiro; Sidle, Roy C; Preechapanya, Pornchai; Sutherland, Ross A; Giambelluca, Thomas W; Jaiaree, Sathaporn

    2006-01-01

    We determined the extent that a riparian buffer reduces stream suspended sediment concentrations by filtering road runoff during 18 rain events in a 2.5-ha, multi-use watershed in northern Thailand. The dominant buffer species was the perennial sedge Fimbristylis aphylla Zoll. ex Steud. (Cyperaceae). We monitored stream sediment concentration for situations where road runoff either flowed into the riparian buffer or was diverted directly into the stream (buffer and no buffer scenarios). These data were used to develop the following relationships between instantaneous stream sediment concentration (Ci) and discharge (Qi): Ci= 28.329Qi(0.851) (buffer scenario) and Ci= 22.265Qi(1.579) (no buffer scenario). Using these functions to calculate total event suspended concentrations, we determined that the buffer reduced suspended sediment concentration by 34 to 87%, for the range of events monitored. Removal of sediment from runoff generated on a 2.4-m-wide, 165-m-long unpaved road section was achieved principally via ponding, which reduced the transport capacity as flow entered the relatively flat, saturated buffer. Sediment deposition occurred primarily within the first 10 m of the buffer. Some sediment was also deposited on the fillslope leading to the buffer. Maximum road sediment concentration during the largest buffer event approached 100,000 mg L(-1). Meanwhile, the corresponding maximum stream suspended sediment concentration was <4000 mg L(-1). In contrast, maximum stream concentrations when flow bypassed the buffer during smaller events were commonly 4000 to 7000 mg L(-1). Naturally occurring buffers represent an economical means of mitigating road-related impacts in upland basins in Southeast Asia, particularly if combined with measures limiting sediment and runoff production on contributing road sections.

  4. Operational Draft Regional Guidebook for the Functional Assessment of High-gradient Ephemeral and Intermittent Headwater Streams in Western West Virginia and Eastern Kentucky

    DTIC Science & Technology

    2010-07-01

    woody debris (VLWD) and functional capacity. ....................... 32 Figure 18: Stream reaches a) with, and b) without riparian/buffer zone forest ...VSUBSTRATE) Median size of the bed material 0.0 to >100.0 inches Large woody debris (VLWD) Number of pieces of LWD 0.0 to >100.0 count Soil detritus...VLWD) This variable is defined as the number of individual pieces of down woody stems per 100 ft (30.5 m) of stream reach within the channel and the

  5. Hydrologic and geochemical factors affecting the chemistry of small headwater streams in response to acidic deposition on Catoctin Mountain, north-central Maryland

    USGS Publications Warehouse

    Rice, Karen C.; Bricker, Owen P.

    1996-01-01

    Hydrologic and water-quality data were collected at a precipitation-collection station and from two small watersheds on Catoctin Mountain, north- central Maryland, as part of an investigation of episodic acidification and its effects on streamwater quality. Data were collected from June 1990 through December 1993. Descriptions of the water shed instrumentation, data-collection techniques, and laboratory methods used to conduct the studies are included. Data that were collected on precipitation, throughfall, soil water, ground water, and streamwater during base flow and stormflow indicate that the streams undergo episodic acidification during storms. Both streams showed decreases in pH to less than 5.0 standard units during stormflow. The acid-neutralizing capacity (ANC) of both streams decreased during stormflow, and the ANC of one of the streams, Bear Branch, became negative. The chemistries of the different types of waters that were sampled indicate that shallow subsurface water with minimal residence time in the watersheds is routed to the streams to become stormflow and is the cause of the episodic acidification observed. Three-component hydrograph separations were performed on the data collected during several storms in each watershed. The hydrograph separations of all of the storms indicate that throughfall contributed 0 to 50 percent of the stormflow, soil water contributed 0 to 80 percent, and ground water contributed 20 to 90 percent. The results of the hydrograph separations indicate that, in general, the watershed with higher hydraulic gradients tends to have shallower and shorter flow paths than the watershed with lower hydraulic gradients.

  6. Effects of Stream Channel Characteristics on Nitrate Delivery to Streams and In-Stream Denitrification Rates, Raccoon River, Iowa

    NASA Astrophysics Data System (ADS)

    Prestegaard, K. L.; O'Connell, M.

    2004-05-01

    Streams in agricultural areas often exhibit significant channel and sediment modifications; they are often incised and transport more fine sediment than non-agricultural streams. These channel characteristics can influence stream water quality by modifying surface-groundwater interactions. In the Raccoon River basin, channel incision increases the delivery of nitrate from the groundwater to the streams. The sandy in-stream sediments, however, serve as very effective sites for in-stream denitrification. Nitrate delivery and in-stream denitrification was examined in 3 subwatersheds of the Raccoon River. Stream morphology, water quality, and sediment characteristics were measured at 35 sites with varying land uses. Headwater stream nitrate concentration increased with percent row crops and the amount of channel incision. Downstream sites showed a wide variation in nitrate concentration with land use. Stream nitrate concentrations were measured at 6 sites in each of 3 streams with high percentages of row crop land uses during high summer baseflow following the 1993 floods and during average summer baseflow in 1995. Nitrate concentrations were systematically higher for the high baseflow conditions of 1993 than the average year (1995). This change in nitrate concentration is interpreted as the increased effectiveness of nitrate delivery to the stream during periods of high water tables. The effect was most pronounced in incised reaches. All 3 streams show downstream decreases in nitrate concentration. Water samples for all the sites in the watersheds were analyzed for nitrogen isotopic composition. The nitrogen isotopic composition shifts with towards higher d 15N values with decreasing nitrate concentration. This is consistent with denitrification reactions that selectively remove the 14N leaving a higher proportion of 15N in the nitrate. This suggests that most of the downstream decrease in nitrate concentrations is a result of in-stream denitrification. The high rates

  7. Variations in surface water-ground water interactions along a headwater mountain stream : comparisons between transient storage and water balance analyses

    USGS Publications Warehouse

    Ward, Adam S.; Payn, Robert A.; Gooseff, Michael N.; McGlynn, Brian L.; Bencala, Kenneth E.; Kelleher, Christa A.; Wondzell, Steven M.; Wagener, Thorsten

    2013-01-01

    The accumulation of discharge along a stream valley is frequently assumed to be the primary control on solute transport processes. Relationships of both increasing and decreasing transient storage, and decreased gross losses of stream water have been reported with increasing discharge; however, we have yet to validate these relationships with extensive field study. We conducted transient storage and mass recovery analyses of artificial tracer studies completed for 28 contiguous 100 m reaches along a stream valley, repeated under four base-flow conditions. We calculated net and gross gains and losses, temporal moments of tracer breakthrough curves, and best fit transient storage model parameters (with uncertainty estimates) for 106 individual tracer injections. Results supported predictions that gross loss of channel water would decrease with increased discharge. However, results showed no clear relationship between discharge and transient storage, and further analysis of solute tracer methods demonstrated that the lack of this relation may be explained by uncertainty and equifinality in the transient storage model framework. Furthermore, comparison of water balance and transient storage approaches reveals complications in clear interpretation of either method due to changes in advective transport time, which sets a the temporal boundary separating transient storage and channel water balance. We have little ability to parse this limitation of solute tracer methods from the physical processes we seek to study. We suggest the combined analysis of both transient storage and channel water balance more completely characterizes transport of solutes in stream networks than can be inferred from either method alone.

  8. Floodplain phosphorus distribution in an agricultural watershed and its role in contributing to in-stream phosphorus load

    NASA Astrophysics Data System (ADS)

    Moustakidis, Iordanis Vlasios

    This thesis presents an experimental study, both in the field and laboratory to cast more light on the primary role of the river floodplains in releasing and/or removing total-P to/from the in-stream load, under high runoff and flood conditions, by investigating the soil total-P spatial and vertical deposition patterns and topsoil erodibility, along the three (3) main river sections (e.g., headwaters, transfer and deposition zones) of an agricultural watershed, such as the Turkey River (TR). In soils, phosphorus, P, primarily exists as sediment-bound and less often as dissolved. During wet hydrological years, soil erosion and surface runoff are the main P release and transport mechanisms, while during dry hydrological years, P leaches to the deeper soil levels and is transported to freshwaters through groundwater discharge. In between the upland areas and the river network, there is a buffer zone, known as floodplain that regulates the flux exchanges between these two watershed components. Floodplains play an essential role in the riverine system health by supporting important physical and biochemical processes and improving the water quality downstream. These characteristics have led to the conclusion that floodplains primarily act as sinks for P. However, floodplains are subject to erosion as well, where soil particles along with the attached P are removed from the topsoil or enter re-suspension, under high runoff and flood conditions. The study provides an insight into the soil total-P deposition patterns across the floodplains of five (5) identified field sites and couples them with topsoil erodibility to eventually address the research objectives, which can be summarized as follows: (i) investigation of the soil total-P spatial and vertical variability across the floodplains along the main river zones and development of relationships between P variability and soil physical properties (e.g., soil texture); (ii) identification and characterization of the soil

  9. Influence of environmental factors on biotic responses to nutrient enrichment in agricultural streams

    USGS Publications Warehouse

    Maret, Terry R.; Konrad, Christopher P.; Tranmer, Andrew W.

    2010-01-01

    The influence of environmental factors on biotic responses to nutrients was examined in three diverse agricultural regions of the United States. Seventy wadeable sites were selected along an agricultural land use gradient while minimizing natural variation within each region. Nutrients, habitat, algae, macroinvertebrates, and macrophyte cover were sampled during a single summer low-flow period in 2006 or 2007. Continuous stream stage and water temperature were collected at each site for 30 days prior to sampling. Wide ranges of concentrations were found for total nitrogen (TN) (0.07-9.61 mg/l) and total phosphorus (TP) (R2) for nutrients and biotic measures across all sites ranged from 0.08 to 0.32 and generally were not higher within each region. The biotic measures (RCHL, SCHL, and AQM) were combined in an index to evaluate eutrophic status across sites that could have different biotic responses to nutrient enrichment. Stepwise multiple regression identified TN, percent canopy, median riffle depth, and daily percent change in stage as significant factors for the eutrophic index (R2 = 0.50, p < 0.001). A TN threshold of 0.48 mg/l was identified where eutrophic index scores became less responsive to increasing TN concentrations, for all sites. Multiple plant growth indicators should be used when evaluating eutrophication, especially when streams contain an abundance of macrophytes.

  10. Evaluation of the negative impacts of exposure to agricultural ditch water in fishes using streamside bioassays and field biomarkers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Land use in regions of the Midwest is dominated by crop agriculture that depends on ditch drainage systems for maximum productivity. Many drainage networks comprise headwater streams that have been degraded by alteration of habitat and by introduction of agrichemicals. Understanding the relative i...

  11. Phytoestrogens and mycotoxins in Iowa streams: An examination of underinvestigated compounds in agricultural basins

    USGS Publications Warehouse

    Kolpin, D.W.; Hoerger, C.C.; Meyer, M.T.; Wettstein, F.E.; Hubbard, L.E.; Bucheli, T.D.

    2010-01-01

    This study provides the first broad-scale investigation on the spatial and temporal occurrence of phytoestrogens and mycotoxins in streams in the United States. Fifteen stream sites across Iowa were sampled five times throughout the 2008 growing season to capture a range of climatic and crop-growth conditions. Basin size upstream from sampling sites ranged from 7 km2 to >836,000 km2. Atrazine (herbicide) also was measured in all samples as a frame-ofreference agriculturally derived contaminant. Target compounds were frequently detected in stream samples: atrazine (100%), formononetin (80%), equol (45%), deoxynivalenol (43%), daidzein (32%), biochanin A (23%), zearalenone (13%), and genistein (11%). Th e nearly ubiquitous detection of formononetin (isoflavone) suggests a widespread agricultural source, as one would expect with the intense row crop and livestock production present across Iowa. Conversely, the less spatially widespread detections of deoxynivalenol (mycotoxin) suggest a more variable source due to the required combination of proper host and proper temperature and moisture conditions necessary to promote Fusarium spp. infections. Although atrazine concentrations commonly exceeded 100 ng L-1 (42/75 measurements), only deoxynivalenol (6/56 measurements) had concentrations that occasionally exceeded this level. Temporal patterns in concentrations varied substantially between atrazine, formononetin, and deoxynivalenol, as one would expect for contaminants with different source inputs and processes of formation and degradation. The greatest phytoestrogen and mycotoxin concentrations were observed during spring snowmelt conditions. Phytoestrogens and mycotoxins were detected at all sampling sites regardless of basin size. The ecotoxicological effects from long-term, low-level exposures to phytoestrogens and mycotoxins or complex chemicals mixtures including these compounds that commonly take place in surface water are poorly understood and have yet to be

  12. Phytoestrogens and mycotoxins in Iowa streams: An examination of underinvestigated compounds in agricultural basins

    USGS Publications Warehouse

    Kolpin, Dana W.; Hoerger, Corinne C.; Meyer, Michael T.; Wettstein, Felix E.; Hubbard, Laura E.; Bucheli, Thomas D.

    2010-01-01

    This study provides the first broad-scale investigation on the spatial and temporal occurrence of phytoestrogens and mycotoxins in streams in the United States. Fifteen stream sites across Iowa were sampled five times throughout the 2008 growing season to capture a range of climatic and crop-growth conditions. Basin size upstream from sampling sites ranged from 7 km2 to >836,000 km2 Atrazine (herbicide) also was measured in all samples as a frame-of-reference agriculturally derived contaminant. Target compounds were frequently detected in stream samples: atrazine (100%), formononetin (80%), equol (45%), deoxynivalenol (43%), daidzein (32%), biochanin A (23%), zearalenone (13%), and genistein (11%). The nearly ubiquitous detection of formononetin (isoflavone) suggests a widespread agricultural source, as one would expect with the intense row crop and livestock production present across Iowa. Conversely, the less spatially widespread detections of deoxynivalenol (mycotoxin) suggest a more variable source due to the required combination of proper host and proper temperature and moisture conditions necessary to promote Fusarium spp. infections. Although atrazine concentrations commonly exceeded 100 ng L-1 (42/75 measurements), only deoxynivalenol (6/56 measurements) had concentrations that occasionally exceeded this level. Temporal patterns in concentrations varied substantially between atrazine, formononetin, and deoxynivalenol, as one would expect for contaminants with different source inputs and processes of formation and degradation. The greatest phytoestrogen and mycotoxin concentrations were observed during spring snowmelt conditions. Phytoestrogens and mycotoxins were detected at all sampling sites regardless of basin size. The ecotoxicological effects from long-term, low-level exposures to phytoestrogens and mycotoxins or complex chemicals mixtures including these compounds that commonly take place in surface water are poorly understood and have yet to be

  13. Influence of Environmental Factors on Biotic Responses to Nutrient Enrichment in Agricultural Streams1

    PubMed Central

    Maret, Terry R; Konrad, Christopher P; Tranmer, Andrew W

    2010-01-01

    The influence of environmental factors on biotic responses to nutrients was examined in three diverse agricultural regions of the United States. Seventy wadeable sites were selected along an agricultural land use gradient while minimizing natural variation within each region. Nutrients, habitat, algae, macroinvertebrates, and macrophyte cover were sampled during a single summer low-flow period in 2006 or 2007. Continuous stream stage and water temperature were collected at each site for 30 days prior to sampling. Wide ranges of concentrations were found for total nitrogen (TN) (0.07-9.61 mg/l) and total phosphorus (TP) (<0.004-0.361 mg/l), but biotic responses including periphytic and sestonic chlorophyll a (RCHL and SCHL, respectively), and percent of stream bed with aquatic macrophyte (AQM) growth were not strongly related to concentrations of TN or TP. Pearson’s coefficient of determination (R2) for nutrients and biotic measures across all sites ranged from 0.08 to 0.32 and generally were not higher within each region. The biotic measures (RCHL, SCHL, and AQM) were combined in an index to evaluate eutrophic status across sites that could have different biotic responses to nutrient enrichment. Stepwise multiple regression identified TN, percent canopy, median riffle depth, and daily percent change in stage as significant factors for the eutrophic index (R2 = 0.50, p < 0.001). A TN threshold of 0.48 mg/l was identified where eutrophic index scores became less responsive to increasing TN concentrations, for all sites. Multiple plant growth indicators should be used when evaluating eutrophication, especially when streams contain an abundance of macrophytes. PMID:22457568

  14. Climate warming and agricultural stressors interact to determine stream periphyton community composition.

    PubMed

    Piggott, Jeremy J; Salis, Romana K; Lear, Gavin; Townsend, Colin R; Matthaei, Christoph D

    2015-01-01

    Lack of knowledge about how the various drivers of global climate change will interact with multiple stressors already affecting ecosystems is the basis for great uncertainty in projections of future biological change. Despite concerns about the impacts of changes in land use, eutrophication and climate warming in running waters, the interactive effects of these stressors on stream periphyton are largely unknown. We manipulated nutrients (simulating agricultural runoff), deposited fine sediment (simulating agricultural erosion) (two levels each) and water temperature (eight levels, 0-6 °C above ambient) simultaneously in 128 streamside mesocosms. Our aim was to determine the individual and combined effects of the three stressors on the algal and bacterial constituents of the periphyton. All three stressors had pervasive individual effects, but in combination frequently produced synergisms at the population level and antagonisms at the community level. Depending on sediment and nutrient conditions, the effect of raised temperature frequently produced contrasting response patterns, with stronger or opposing effects when one or both stressors were augmented. Thus, warming tended to interact negatively with nutrients or sediment by weakening or reversing positive temperature effects or strengthening negative ones. Five classes of algal growth morphology were all affected in complex ways by raised temperature, suggesting that these measures may prove unreliable in biomonitoring programs in a warming climate. The evenness and diversity of the most abundant bacterial taxa increased with temperature at ambient but not with enriched nutrient levels, indicating that warming coupled with nutrient limitation may lead to a more evenly distributed bacterial community as temperatures rise. Freshwater management decisions that seek to avoid or mitigate the negative effects of agricultural land use on stream periphyton should be informed by knowledge of the interactive effects of

  15. The influence of nutrients and physical habitat in regulating algal biomass in agricultural streams

    USGS Publications Warehouse

    Munn, Mark D.; Frey, Jeffrey W.; Tesoriero, Anthony J.

    2010-01-01

    This study examined the relative influence of nutrients (nitrogen and phosphorus) and habitat on algal biomass in five agricultural regions of the United States. Sites were selected to capture a range of nutrient conditions, with 136 sites distributed over five study areas. Samples were collected in either 2003 or 2004, and analyzed for nutrients (nitrogen and phosphorous) and algal biomass (chlorophyll a). Chlorophyll a was measured in three types of samples, fine-grained benthic material (CHLFG), coarse-grained stable substrate as in rock or wood (CHLCG), and water column (CHLS). Stream and riparian habitat were characterized at each site. TP ranged from 0.004–2.69 mg/l and TN from 0.15–21.5 mg/l, with TN concentrations highest in Nebraska and Indiana streams and TP highest in Nebraska. Benthic algal biomass ranged from 0.47–615 mg/m2, with higher values generally associated with coarse-grained substrate. Seston chlorophyll ranged from 0.2–73.1 μg/l, with highest concentrations in Nebraska. Regression models were developed to predict algal biomass as a function of TP and/or TN. Seven models were statistically significant, six for TP and one for TN; r2 values ranged from 0.03 to 0.44. No significant regression models could be developed for the two study areas in the Midwest. Model performance increased when stream habitat variables were incorporated, with 12 significant models and an increase in the r2 values (0.16–0.54). Water temperature and percent riparian canopy cover were the most important physical variables in the models. While models that predict algal chlorophyll a as a function of nutrients can be useful, model strength is commonly low due to the overriding influence of stream habitat. Results from our study are presented in context of a nutrient-algal biomass conceptual model.

  16. Erosion, sediment discharge, and channel morphology in the upper Chattahoochee River basin, Georgia, with a discussion of the contribution of suspended sediment to stream quality

    USGS Publications Warehouse

    Faye, Robert E.; Carey, W.P.; Stamer, J.K.; Kleckner, R.L.

    1980-01-01

    The 3,550 square miles of the Upper Chattahoochee River basin is an area of diverse physiographic and land-use characteristics. The headwater areas are mountainous with steep, relatively narrow channels. Land in the headwater areas is heavily forested, but small towns and farms are common in the valleys of large streams. Downstream, the basin is characterized by low hills and wider stream channels. Land in this part of the basin is also predominantly forested; however, large agricultural and urban areas are common. Urban land use is particularly intensive within the Atlanta Metropolitan Area.

  17. Suckers in headwater tributaries, Wyoming

    USGS Publications Warehouse

    Sweet, D.E.; Compton, R.I.; Hubert, W.A.

    2009-01-01

    Bluehead sucker (Catostomus discobolus) and flannelmouth sucker (Catostomus latipinnis) populations are declining throughout these species' native ranges in the Upper Colorado River Basin. In order to conserve these populations, an understanding of population dynamics is needed. Using age estimates from pectoral fin rays, we describe age and growth of these 2 species in 3 Wyoming stream systems: Muddy Creek, the Little Sandy River, and the Big Sandy River. Within all 3 stream systems, flannelmouth suckers were longer-lived than bluehead suckers, with maximum estimated ages of 16 years in Muddy Creek, 18 years in Little Sandy Creek, and 26 years in the Big Sandy River. Bluehead suckers had maximum estimated ages of 8 years in Muddy Creek, 10 years in Little Sandy Creek, and 18 years in the Big Sandy River. These maximum estimated ages were substantially greater than in other systems where scales have been used to estimate ages. Mean lengths at estimated ages were greater for flannelmouth suckers than for bluehead suckers in all 3 streams and generally less than values published from other systems where scales were used to estimate ages. Our observations of long life spans and slow growth rates among bluehead suckers and flannelmouth suckers were probably associated with our use of fin rays to estimate ages as well as the populations being in headwater tributaries near the northern edges of these species' ranges.

  18. Identifying diffused nitrate sources in a stream in an agricultural field using a dual isotopic approach.

    PubMed

    Ding, Jingtao; Xi, Beidou; Gao, Rutai; He, Liansheng; Liu, Hongliang; Dai, Xuanli; Yu, Yijun

    2014-06-15

    Nitrate (NO3(-)) pollution is a severe problem in aquatic systems in Taihu Lake Basin in China. A dual isotope approach (δ(15)NNO3(-) and δ(18)ONO3(-)) was applied to identify diffused NO3(-) inputs in a stream in an agricultural field at the basin in 2013. The site-specific isotopic characteristics of five NO3(-) sources (atmospheric deposition, AD; NO3(-) derived from soil organic matter nitrification, NS; NO3(-) derived from chemical fertilizer nitrification, NF; groundwater, GW; and manure and sewage, M&S) were identified. NO3(-) concentrations in the stream during the rainy season [mean±standard deviation (SD)=2.5±0.4mg/L] were lower than those during the dry season (mean±SD=4.0±0.5mg/L), whereas the δ(18)ONO3(-) values during the rainy season (mean±SD=+12.3±3.6‰) were higher than those during the dry season (mean±SD=+0.9±1.9‰). Both chemical and isotopic characteristics indicated that mixing with atmospheric NO3(-) resulted in the high δ(18)O values during the rainy season, whereas NS and M&S were the dominant NO3(-) sources during the dry season. A Bayesian model was used to determine the contribution of each NO3(-) source to total stream NO3(-). Results showed that reduced N nitrification in soil zones (including soil organic matter and fertilizer) was the main NO3(-) source throughout the year. M&S contributed more NO3(-) during the dry season (22.4%) than during the rainy season (17.8%). AD generated substantial amounts of NO3(-) in May (18.4%), June (29.8%), and July (24.5%). With the assessment of temporal variation of diffused NO3(-) sources in agricultural field, improved agricultural management practices can be implemented to protect the water resource and avoid further water quality deterioration in Taihu Lake Basin.

  19. Local physical habitat quality cloud the effect of predicted pesticide runoff from agricultural land in Danish streams.

    PubMed

    Rasmussen, Jes Jessen; Baattrup-Pedersen, Annette; Larsen, Søren Erik; Kronvang, Brian

    2011-04-01

    The combination of intensive agricultural activities and the close connectivity between land and stream emphasise the potential risk of pesticide exposure in Danish streams. Benthic macroinvertebrates are applied in the assessment of stream ecological status, and some sensitive species have been shown to respond strongly to brief pulses of pesticide contamination. In this study we investigate the impact of agriculturally derived pesticides on stream macroinvertebrate communities in Denmark. As a measure of toxic pressure we apply the Runoff Potential. We investigated a total of 212 streams. These were grouped into distinct classes according to the magnitude of pesticide contamination in the period from 2003-2006. A total of 24 different macroinvertebrate indices were applied to detect effects of pesticide runoff (e.g. the SPEAR-index and the number of EPT taxa). We found high predicted pesticide runoff in 39% of the streams, but we found no significant effect of predicted pesticide exposure on stream macroinvertebrate indices. We, additionally, examined the influence of a series of environmental parameters ranging from site scale to catchment scale on the macroinvertebrate community. Relative proportions of gravel, sand and silt in bed sediments explained most of the variation in macroinvertebrate indices as well as the upstream riparian habitat quality. We suggest that the Runoff Potential model overestimate pesticide runoff contamination in Danish streams due the presence of buffer strips enforced by Danish legislation. When pesticide runoff contamination is low to moderate, poor physical properties (indirectly related to agricultural activity) are the main impediment for the ecological quality of Danish streams.

  20. CROSS-STREAM COMPARISON OF SUBSTRATE-SPECIFIC DENITRIFICATION POTENTIAL

    SciTech Connect

    Findlay, Stuart; Mulholland, Patrick J; Hamilton, Stephen; Tank, Jennifer; Bernot, Melody; Burgin, Amy; Crenshaw, Chelsea; Grimm, Nancy; McDowell, William; Potter, Jody; Sobota, Daniel

    2011-01-01

    Headwater streams have a demonstrated ability to denitrify a portion of their nitrate (NO(3) (-)) load but there has not been an extensive consideration of where in a stream this process is occurring and how various habitats contribute to total denitrification capability. As part of the Lotic Intersite Nitrogen Experiment II (LINX II) we measured denitrification potential in 65 streams spanning eight regions of the US and draining three land-use types. In each stream, potential denitrification rates were measured in common substrate types found across many streams as well as locations unique to particular streams. Overall, habitats from streams draining urban and agricultural land-uses showed higher potential rates of denitrification than reference streams draining native vegetation. This difference among streams was probably driven by higher ambient nitrate concentrations found in urban or agricultural streams. Within streams, sandy habitats and accumulations of fine benthic organic matter contributed more than half of the total denitrification capacity (mg N removed m(-2) h(-1)). A particular rate of potential denitrification per unit area could be achieved either by high activity per unit organic matter or lower activities associated with larger standing stocks of organic matter. We found that both small patches with high rates (hot spots) or more widespread but less active areas (cool matrix) contributed significantly to whole stream denitrification capacity. Denitrification estimated from scaled-up denitrification enzyme assay (DEA) potentials were not always dramatically higher than in situ rates of denitrification measured as (15)N gas generation following 24-h (15)N-NO(3) tracer additions. In general, headwater streams draining varying land-use types have significant potential to remove nitrate via denitrification and some appear to be functioning near their maximal capacity.

  1. Nitrate removal effectiveness of a riparian buffer along a small agricultural stream in western Oregon.

    PubMed

    Wigington, P J; Griffith, S M; Field, J A; Baham, J E; Horwath, W R; Owen, J; Davis, J H; Rain, S C; Steiner, J J

    2003-01-01

    The Willamette Valley of Oregon has extensive areas of poorly drained, commercial grass seed lands. Little is know about the ability of riparian areas in these settings to reduce nitrate in water draining from grass seed fields. We established two study sites with similar soils and hydrology but contrasting riparian vegetation along an intermittent stream that drains perennial ryegrass (Lolium perenne L.) fields in the Willamette Valley of western Oregon. We installed a series of nested piezometers along three transects at each site to examine NO3-N in shallow ground water in grass seed fields and riparian areas. Results showed that a noncultivated riparian zone comprised of grasses and herbaceous vegetation significantly reduced NO3-N concentrations of shallow ground water moving from grass seed fields. Darcy's law-based estimates of shallow ground water flow through riparian zone A/E horizons revealed that this water flowpath could account for only a very small percentage of the streamflow. Even though there is great potential for NO3-N to be reduced as water moves through the noncultivated riparian zone with grass-herbaceous vegetation, the potential was not fully realized because only a small proportion of the stream flow interacts with riparian zone soils. Consequently, effective NO3-N water quality management in poorly drained landscapes similar to the study watershed is primarily dependent on implementation of sound agricultural practices within grass seed fields and is less influenced by riparian zone vegetation. Wise fertilizer application rates and timing are key management tools to reduce export of NO3-N in stream waters.

  2. Evaluating stream sediment chemistry within an agricultural catchment of Lebanon, Northeastern USA.

    PubMed

    Oyewumi, Oluyinka; Feldman, Jonathan; Gourley, Jonathan R

    2017-04-01

    Recent arsenic pollution of drinking-water wells across Lebanon, northeastern USA has led to a growing concern about possible impact of agricultural activities on the hydrologic system. This study assessed the concentrations and distributions of arsenic and ten other elements (Al, Cd, Cr, Cu, Fe, K, Mn, P, Pb, and Zn) in stream sediments. The overall goal is to determine the extent of these elements within the fluvial systems, as well as overall sediment quality. A total of 65 stream sediments samples were collected, and analyzed for particle size distributions, organic matter contents, trace, and major elements concentrations. Results showed spatial variability in the concentrations of trace elements due to variation in sediments grain sizes, organic matter content, as well as land use activities within the study area. Calculation of sediment enrichment with respect to As, Cd, Cr, Cu, Mn, Pb, and Zn showed that about 48-52% of all the sampling locations are not enriched, nevertheless, approximately 2-11% of all the sampling locations are significantly enriched, an indication of anthropogenic input. However, results of ecological risk assessment showed no connection with sediment enrichment as most sampling locations have concentrations below the threshold probable effect concentration (PEC) value. Statistical analysis using principal component analysis (PCA) extracted three significant components explaining over 72% of total variance covering elements having origin in both natural and anthropogenic sources, thus suggesting that the concentrations and distribution of these elements within stream sediments are related to a combination of weathering processes on the bedrock geology, and anthropogenic activities.

  3. Floodplain restoration enhances denitrification and reach-scale nitrogen removal in an agricultural stream.

    PubMed

    Roley, Sarah S; Tank, Jennifer L; Stephen, Mia L; Johnson, Laura T; Beaulieu, Jake J; Witter, Jonathan D

    2012-01-01

    Streams of the agricultural Midwest, USA, export large quantities of nitrogen, which impairs downstream water quality, most notably in the Gulf of Mexico. The two-stage ditch is a novel restoration practice, in which floodplains are constructed alongside channelized ditches. During high flows, water flows across the floodplains, increasing benthic surface area and stream water residence time, as well as the potential for nitrogen removal via denitrification. To determine two-stage ditch nitrogen removal efficacy, we measured denitrification rates in the channel and on the floodplains of a two-stage ditch in north-central Indiana for one year before and two years after restoration. We found that instream rates were similar before and after the restoration, and they were influenced by surface water NO3- concentration and sediment organic matter content. Denitrification rates were lower on the constructed floodplains and were predicted by soil exchangeable NO3- concentration. Using storm flow simulations, we found that two-stage ditch restoration contributed significantly to NO3- removal during storm events, but because of the high NO3- loads at our study site, < 10% of the NO3- load was removed under all storm flow scenarios. The highest percentage of NO3- removal occurred at the lowest loads; therefore, the two-stage ditch's effectiveness at reducing downstream N loading will be maximized when the practice is coupled with efforts to reduce N inputs from adjacent fields.

  4. [Agricultural land use impacts on aquatic macroinvertebrates in small streams from La Vieja river (Valle del Cauca, Colombia].

    PubMed

    Giraldo, Lina Paola; Chará, Julián; Zúñiga, Maria del Carmen; Chará-Serna, Ana Marcela; Pedraza, Gloria

    2014-04-01

    The expansion of the agricultural frontier in Colombia has exerted significant pressure on its aquatic ecosystems during the last few decades. In order to determine the impacts of different agricultural land uses on the biotic and abiotic characteristics of first and second order streams of La Vieja river watershed, we evaluated 21 streams located between 1,060 and 1,534 m asl in the municipalities of Alcalá, Ulloa, and Cartago (Valle del Cauca, Colombia). Seven streams were protected by native vegetation buffers, eight had influence of coffee and plantain crops, and six were influenced by cattle ranching. Habitat conditions, channel dimensions, water quality, and aquatic macroinvertebrates were studied in each stream. Streams draining cattle ranching areas had significantly higher dissolved solids, higher phosphorus, higher alkalinity, higher conductivity, and lower dissolved oxygen than those covered by cropland and forests. Coarse substrates and diversity of flow regimes were significantly higher in cropland and protected streams when compared to streams affected by cattle ranching, whereas the percent of silt and slow currents was significantly higher in the latter. A total of 26,777 macroinvertebrates belonging to 17 orders, 72 families and 95 genera were collected. The most abundant groups were Diptera 62.8%, (Chironomidae 49.6%, Ceratopogonidae 6.7%), Mollusca 18.8% (Hydrobiidae 7.2%, Sphaeriidae 9.6%) and Trichoptera 5.7% (Hydropsychidae 3.7%). The Ephemeroptera, Trichoptera, and Plecoptera orders, known for their low tolerance to habitat perturbation, had high abundance in cropland and forested streams, whereas Diptera and Mollusca were more abundant in those impacted by cattle ranching. Results indicate that streams draining forests and croplands have better physical and biological conditions than those draining pastures, and highlight the need to implement protective measures to restore the latter.

  5. A synoptic survey of ecosystem services from headwater catchments in the United States (presentation)

    EPA Science Inventory

    Ecosystem production functions for water supply, climate regulation, and water purification were estimated for 568 headwater streams and their catchments. Water supply per unit catchment area was highest in the Northern Appalachian Mountains and lowest in the Northern Plains. C, ...

  6. A synoptic survey of ecosystem services from headwater catchments in the United States- webinar

    EPA Science Inventory

    Ecosystem production functions for water supply, climate regulation, and water purification were estimated for 568 headwater streams and their catchments. Water supply per unit catchment area was highest in the Northern Appalachian Mountains and lowest in the Northern Plains. C, ...

  7. Riparian forest effects on nitrogen export to an agricultural stream inferred from experimental data and a model

    EPA Science Inventory

    The effects of riparian vegetation on the reduction of agricultural nitrogen export to streams have been well described experimentally, but a clear understanding of process-level hydrological and biogeochemical controls can be difficult to ascertain from data alone. We apply a ne...

  8. Effects of watershed densities of animal feeding operations on nutrient concentrations and estrogenic activity in agricultural streams

    USGS Publications Warehouse

    Ciparis, S.; Iwanowicz, L.R.; Voshell, J.R.

    2012-01-01

    Application of manures from animal feeding operations (AFOs) as fertilizer on agricultural land can introduce nutrients and hormones (e.g. estrogens) to streams. A landscape-scale study was conducted in the Shenandoah River watershed (Virginia, USA) in order to assess the relationship between densities of AFOs in watersheds of agricultural streams and in-stream nutrient concentrations and estrogenic activity. The effect of wastewater treatment plants (WWTPs) on nutrients and estrogenic activity was also evaluated. During periods of high and low flow, dissolved inorganic nitrogen (DIN) and orthophosphate (PO 4-P) concentrations were analyzed and estrogens/estrogenic compounds were extracted and quantified as17??-estradiol equivalents (E2Eq) using a bioluminescent yeast estrogen screen. Estrogenic activity was measurable in the majority of collected samples, and 20% had E2Eq concentrations >1ng/L. Relatively high concentrations of DIN (>1000??g/L) were also frequently detected. During all sampling periods, there were strong relationships between watershed densities of AFOs and in-stream concentrations of DIN (R 2=0.56-0.81) and E2Eq (R 2=0.39-0.75). Relationships between watershed densities of AFOs and PO 4-P were weaker, but were also significant (R 2=0.27-0.57). When combined with the effect of watershed AFO density, streams receiving WWTP effluent had higher concentrations of PO 4-P than streams without WWTP discharges, and PO 4-P was the only analyte with a consistent relationship to WWTPs. The results of this study suggest that as the watershed density of AFOs increases, there is a proportional increase in the potential for nonpoint source pollution of agricultural streams and their receiving waters by nutrients, particularly DIN, and compounds that can cause endocrine disruption in aquatic organisms. ?? 2011 Elsevier B.V.

  9. Effects of watershed densities of animal feeding operations on nutrient concentrations and estrogenic activity in agricultural streams

    USGS Publications Warehouse

    Ciparis, Serena; Iwanowicz, Luke R.; Voshell, J. Reese

    2012-01-01

    Application of manures from animal feeding operations (AFOs) as fertilizer on agricultural land can introduce nutrients and hormones (e.g. estrogens) to streams. A landscape-scale study was conducted in the Shenandoah River watershed (Virginia, USA) in order to assess the relationship between densities of AFOs in watersheds of agricultural streams and in-stream nutrient concentrations and estrogenic activity. The effect of wastewater treatment plants (WWTPs) on nutrients and estrogenic activity was also evaluated. During periods of high and low flow, dissolved inorganic nitrogen (DIN) and orthophosphate (PO4-P) concentrations were analyzed and estrogens/estrogenic compounds were extracted and quantified as17β-estradiol equivalents (E2Eq) using a bioluminescent yeast estrogen screen. Estrogenic activity was measurable in the majority of collected samples, and 20% had E2Eq concentrations > 1 ng/L. Relatively high concentrations of DIN (> 1000 μg/L) were also frequently detected. During all sampling periods, there were strong relationships between watershed densities of AFOs and in-stream concentrations of DIN (R2 = 0.56–0.81) and E2Eq (R2 = 0.39–0.75). Relationships between watershed densities of AFOs and PO4-P were weaker, but were also significant (R2 = 0.27–0.57). When combined with the effect of watershed AFO density, streams receiving WWTP effluent had higher concentrations of PO4-P than streams without WWTP discharges, and PO4-P was the only analyte with a consistent relationship to WWTPs. The results of this study suggest that as the watershed density of AFOs increases, there is a proportional increase in the potential for nonpoint source pollution of agricultural streams and their receiving waters by nutrients, particularly DIN, and compounds that can cause endocrine disruption in aquatic organisms.

  10. Hydrological and environmental controls of the stream nitrate concentration and flux in a small agricultural watershed

    NASA Astrophysics Data System (ADS)

    Zhou, Y.; Xu, J. F.; Yin, W.; Ai, L.; Fang, N. F.; Tan, W. F.; Yan, F. L.; Shi, Z. H.

    2017-02-01

    Nitrate exports from diffuse sources constitute a major cause of eutrophication and episodic acidification in inland aquatic systems, and remedial action requires the identification of the influencing factors associated with these nitrate exports. This paper examines the combined effects of watershed complexity on nitrate concentration and flux in terms of the hydrological and environmental factors in heterogeneous nested subwatersheds in the Danjiangkou Reservoir Area (DRA), China. We established 15 sampling sites in the main stream and tributaries and conducted biweekly sampling in 2008-2012 to monitor the nitrate exports. The hydrological and environmental indices within the watershed were divided into subwatersheds and considered as potential influencing factors. In consideration of the high co-linearity of these influencing factors, we used partial least squares regression (PLSR) to determine the associations between the stream nitrate concentration or flux and 26 selected watershed characteristics. The number of components was unequal for the nitrate concentration and flux models. The optimal models explained 66.4%, 60.0% and 59.9% of the variability in nitrate concentration and 74.7%, 67.1% and 58.0% of the variability in nitrate flux annually, in the dry season, and in the wet season, respectively. According to the variable importance in the projection (VIP) values, the dominant first-order factors for the nitrate concentration were as follows: the areal percentages of agricultural, forest and residential areas; followed by the slope; the largest patch index (LPI); the flow path gradient (FPG); the slope gradient variance (SGV); and the splitting index (SPLIT). In addition to these factors, the runoff coefficient (RC), flashiness index (FI), and patch density (PD) affected the changes in the nitrate flux. This study illustrates the influence of hydrological and environmental factors on seasonal water quality and can serve as guidelines for better watershed

  11. Pharmaceutical contamination in residential, industrial, and agricultural waste streams: risk to aqueous environments in Taiwan.

    PubMed

    Lin, Angela Yu-Chen; Yu, Tsung-Hsien; Lin, Cheng-Fang

    2008-12-01

    This is a comprehensive study of the occurrence of antibiotics, hormones and other pharmaceuticals in water sites that have major potential for downstream environmental contamination. These include residential (hospitals, sewage treatment plants, and regional discharges), industrial (pharmaceutical production facilities), and agricultural (animal husbandries and aquacultures) waste streams. We assayed 23 Taiwanese water sites for 97 targeted compounds, of which a significant number were detected and quantified. The most frequently detected compounds were sulfamethoxazole, caffeine, acetaminophen, and ibuprofen, followed closely by cephalexin, ofloxacin, and diclofenac, which were detected in >91% of samples and found to have median (maximum) concentrations of 0.2 (5.8), 0.39 (24.0), 0.02 (100.4), 0.41 (14.5), 0.15 (31.4), 0.14 (13.6) and 0.083 (29.8) microg/L, respectively. Lincomycin and acetaminophen had high measured concentrations (>100 microg/L), and 35 other pharmaceuticals occurred at the microg/L level. These incidence and concentration results correlate well with published data for other worldwide locations, as well as with Taiwanese medication usage data, suggesting a human contamination source. Many pharmaceuticals also occurred at levels exceeding predicted no-effect concentrations (PNEC), warranting further investigation of their occurrence and fate in receiving waters, as well as the overall risks they pose for local ecosystems and human residents. The information provided here will also be useful for development of strategies for regulation and remediation.

  12. Macroinvertebrate assemblages in agricultural, mining, and urban tropical streams: implications for conservation and management.

    PubMed

    Mwedzi, Tongayi; Bere, Taurai; Mangadze, Tinotenda

    2016-06-01

    The study evaluated the response of macroinvertebrate assemblages to changes in water quality in different land-use settings in Manyame catchment, Zimbabwe. Four land-use categories were identified: forested commercial farming, communal farming, Great Dyke mining (GDM) and urban areas. Macroinvertebrate community structure and physicochemical variables data were collected in two seasons from 41 sites following standard methods. Although not environmentally threatening, urban and GDM areas were characterised by higher conductivity, total dissolved solids, salinity, magnesium and hardness. Chlorides, total phosphates, total nitrogen, calcium, potassium and sodium were significantly highest in urban sites whilst dissolved oxygen (DO) was significantly higher in the forested commercial faming and GDM sites. Macroinvertebrate communities followed the observed changes in water quality. Macroinvertebrates in urban sites indicated severe pollution (e.g. Chironomidae) whilst those in forested commercial farming sites and GDM sites indicated relatively clean water (e.g. Notonemouridae). Forested watersheds together with good farm management practices are important in mitigating impacts of urbanisation and agriculture. Strategies that reduce oxygen-depleting substances must be devised to protect the health of Zimbabwean streams. The study affirms the wider applicability of the South African Scoring System in different land uses.

  13. Use of Continuous Specific Conductance to Differentiate the Sources of Water to an Agricultural Stream With Subsurface Drainage Networks

    NASA Astrophysics Data System (ADS)

    Smith, E. A.; Thornburg, J.; Capel, P. D.

    2008-12-01

    The sources of water to natural streams include direct precipitation, overland flow, and ground-water inflow. In glaciated areas, the presence of artificial surface and subsurface drainage networks, a common practice for removing excess water from agricultural fields, provides additional pathways of water movement to the stream. The artificial drainage of agricultural fields allows rainfall to move quickly through the catchment to the stream transporting nutrients, pesticides and other agricultural-related constituents. A largely agricultural (about 90%), 31 km2 subcatchment of the South Fork of the Iowa River in north-central Iowa was studied for two years. Discharge and specific conductance (SC) were measured continuously and discreet water samples were obtained for analyses of nutrients and other constituents. SC is an electrical measurement of the total ion content in the water. The SC of the rain and ground-water is about 10 microS/cm and 800-1,200 microS/cm, respectively. The typical, base-flow SC of the stream is 700-800 microS/cm. Within minutes after a substantial rain event, the stream discharge increases and the SC decreases (often times below 200"nmicroS/cm). The rain water is processed through the catchment before it reaches the stream via direct overland flow, preferential flow to subsurface drains, vertical drains attached to subsurface drains in ponded areas, and/or soil infiltration to ground-water. Water moving through each of these pathways has different characteristic time scales and different degrees of interactions with the soil yielding different ionic content, thus different SC. Both the discharge and SC concurrently return to the typical base-flow values over the following days and weeks. This strong relation between rainfall, discharge and SC is used to calculate the relative importance and time scale of the various hydrologic pathways. In addition to the two-year stream record, complementary discharge and SC data were collected in two

  14. Salinity and sodium hazards of three streams of different agricultural land use systems in Ile-Ife, Nigeria

    NASA Astrophysics Data System (ADS)

    Ogunfowokan, A. O.; Obisanya, J. F.; Ogunkoya, O. O.

    2013-03-01

    In this study, three streams—Amuta, Agbogbo and Abagbooro were examined for salinity and sodium hazards and suitability of the water for irrigational purpose. The three streams are located within areas of three different agricultural practices and land uses. Water samples from the streams were collected twice a month for 1 year. Irrigation water quality parameters assessed included pH, electrical conductivity (EC), sodium adsorption ratio (SAR), percentage sodium, permeability index and potential salinity. Water samples were analyzed using standard chemical procedures. Results of the irrigation water quality parameters studied showed that water samples from the three streams do not exhibit toxicity problem in relation to salinity and sodium hazard. Although the data obtained for the three catchment areas for pH, EC and SAR were closely related, least concentrations of these irrigation water indices were obtained for Abagbooro stream where there is secondary forest; highest concentrations were found in Agbogbo stream and moderate values were obtained for water from Amuta stream where subsistent and mechanized farming are practiced, respectively.

  15. Relating land use patterns to stream nutrient levels in red soil agricultural catchments in subtropical central China.

    PubMed

    Wang, Yi; Li, Yong; Liu, Xinliang; Liu, Feng; Li, Yuyuan; Song, Lifang; Li, Hang; Ma, Qiumei; Wu, Jinshui

    2014-09-01

    Land use has obvious influence on surface water quality; thus, it is important to understand the effects of land use patterns on surface water quality. This study explored the relationships between land use patterns and stream nutrient levels, including ammonium-N (NH4 (+)-N), nitrate-N (NO3 (-)-N), total N (TN), dissolved P (DP), and total P (TP) concentrations, in one forest and 12 agricultural catchments in subtropical central China. The results indicated that the TN concentrations ranged between 0.90 and 6.50 mg L(-1) and the TP concentrations ranged between 0.08 and 0.53 mg L(-1), showing that moderate nutrient pollution occurred in the catchments. The proportional areal coverages of forests, paddy fields, tea fields, residential areas, and water had distinct effects on stream nutrient levels. Except for the forest, all studied land use types had a potential to increase stream nutrient levels in the catchments. The land use pattern indices at the landscape level were significantly correlated to N nutrients but rarely correlated to P nutrients in stream water, whereas the influence of the land use pattern indices at the class level on stream water quality differentiated among the land use types and nutrient species. Multiple regression analysis suggested that land use pattern indices at the class level, including patch density (PD), largest patch index (LPI), mean shape index (SHMN), and mean Euclidian nearest neighbor distance (ENNMN), played an intrinsic role in influencing stream nutrient quality, and these four indices explained 35.08 % of the variability of stream nutrient levels in the catchments (p<0.001). Therefore, this research provides useful ideas and insights for land use planners and managers interested in controlling stream nutrient pollution in subtropical central China.

  16. Identifying pathways and processes affecting nitrate and orthophosphate inputs to streams in agricultural watersheds.

    PubMed

    Tesoriero, Anthony J; Duff, John H; Wolock, David M; Spahr, Norman E; Almendinger, James E

    2009-01-01

    Understanding nutrient pathways to streams will improve nutrient management strategies and estimates of the time lag between when changes in land use practices occur and when water quality effects that result from these changes are observed. Nitrate and orthophosphate (OP) concentrations in several environmental compartments were examined in watersheds having a range of base flow index (BFI) values across the continental United States to determine the dominant pathways for water and nutrient inputs to streams. Estimates of the proportion of stream nitrate that was derived from groundwater increased as BFI increased. Nitrate concentration gradients between groundwater and surface water further supported the groundwater source of nitrate in these high BFI streams. However, nitrate concentrations in stream-bed pore water in all settings were typically lower than stream or upland groundwater concentrations, suggesting that nitrate discharge to streams was not uniform through the bed. Rather, preferential pathways (e.g., springs, seeps) may allow high nitrate groundwater to bypass sites of high biogeochemical transformation. Rapid pathway compartments (e.g., overland flow, tile drains) had OP concentrations that were typically higher than in streams and were important OP conveyers in most of these watersheds. In contrast to nitrate, the proportion of stream OP that is derived from ground water did not systematically increase as BFI increased. While typically not the dominant source of OP, groundwater discharge was an important pathway of OP transport to streams when BFI values were very high and when geochemical conditions favored OP mobility in groundwater.

  17. Effects of agricultural best-management practices on the Brush Run Creek headwaters, Adams County, Pennsylvania, prior to and during nutrient management

    USGS Publications Warehouse

    Langland, M.J.; Fishel, D.K.

    1996-01-01

    The U.S. Geological Survey, in cooperation with the Susquehanna River Basin Commission and the Pennsylvania Department of Environmental Resources, investigated the effects of agricultural best-management practices on surface-water quality as part of the U.S. Environmental Protection Agency's Chesapeake Bay Program. This report characterizes a 0.63-square- mile agricultural watershed underlain by shale, mudstone, and red arkosic sandstone in the Lower Susquehanna River Basin. The water quality of the Brush Run Creek site was studied from October 1985 through September 1991, prior to and during the implementation of nutrient management designed to reduce sediment and nutrient discharges into Conewago Creek, a tributary to the Chesapeake Bay. The original study area was 0.38 square mile and included an area immediately upstream from a manure lagoon. The study area was increased to 0.63 square mile in the fall of 1987 after an extensive tile-drain network was discovered upstream and downstream from the established streamflow gage, and the farm owner made plans to spray irrigate manure to the downstream fields. Land use for about 64 percent of the 0.63 square mile watershed is cropland, 14 percent is pasture, 7 percent is forest, and the remaining 15 percent is yards, buildings, water, or gardens. About 73 percent of the cropland was used to produce corn during the study. The average annual animal population consisted of 57,000 chickens, 1,530 hogs, and 15 sheep during the study. About 59,340 pounds of nitrogen and 13,710 pounds of phosphorus were applied as manure and commercial fertilizer to fields within the subbasin during the 3-year period prior to implementation of nutrient management. During nutrient management, about 14 percent less nitrogen and 57 percent less phosphorus were applied as commercial and manure fertilizer. Precipitation totaled 209 inches, or 13 percent less than the long-term normal, during the 6-year study. Concentrations of total ammonia in

  18. A study of the effects of implementing agricultural best management practices and in-stream restoration on suspended sediment, stream habitat, and benthic macroinvertebrates at three stream sites in Surry County, North Carolina, 2004-2007-Lessons learned

    USGS Publications Warehouse

    Smith, Douglas G.; Ferrell, G.M.; Harned, Douglas A.; Cuffney, Thomas F.

    2011-01-01

    The effects of agricultural best management practices and in-stream restoration on suspended-sediment concentrations, stream habitat, and benthic macroinvertebrate assemblages were examined in a comparative study of three small, rural stream basins in the Piedmont and Blue Ridge Physiographic Provinces of North Carolina and Virginia between 2004 and 2007. The study was designed to assess changes in stream quality associated with stream-improvement efforts at two sites in comparison to a control site (Hogan Creek), for which no improvements were planned. In the drainage basin of one of the stream-improvement sites (Bull Creek), several agricultural best management practices, primarily designed to limit cattle access to streams, were implemented during this study. In the drainage basin of the second stream-improvement site (Pauls Creek), a 1,600-foot reach of the stream channel was restored and several agricultural best management practices were implemented. Streamflow conditions in the vicinity of the study area were similar to or less than the long-term annual mean streamflows during the study. Precipitation during the study period also was less than normal, and the geographic distribution of precipitation indicated drier conditions in the southern part of the study area than in the northern part. Dry conditions during much of the study limited opportunities for acquiring high-flow sediment samples and streamflow measurements. Suspended-sediment yields for the three basins were compared to yield estimates for streams in the southeastern United States. Concentrations of suspended sediment and nutrients in samples from Bull Creek, the site where best management practices were implemented, were high compared to the other two sites. No statistically significant change in suspended-sediment concentrations occurred at the Bull Creek site following implementation of best management practices. However, data collected before and after channel stabilization at the Pauls

  19. Contamination with bacterial zoonotic pathogen genes in U.S. streams influenced by varying types of animal agriculture

    USGS Publications Warehouse

    Haack, Sheridan K.; Duris, Joseph W.; Kolpin, Dana W.; Focazio, Michael J.; Meyer, Michael T.; Johnson, Heather E.; Oster, Ryan J.; Foreman, William T.

    2016-01-01

    Animal waste, stream water, and streambed sediment from 19 small (< 32 km2) watersheds in 12 U.S. states having either no major animal agriculture (control, n = 4), or predominantly beef (n = 4), dairy (n = 3), swine (n = 5), or poultry (n = 3) were tested for: 1) cholesterol, coprostanol, estrone, and fecal indicator bacteria (FIB) concentrations, and 2) shiga-toxin producing and enterotoxigenic Escherichia coli, Salmonella, Campylobacter, and pathogenic and vancomycin-resistant enterococci by polymerase chain reaction (PCR) on enrichments, and/or direct quantitative PCR. Pathogen genes were most frequently detected in dairy wastes, followed by beef, swine and poultry wastes in that order; there was only one detection of an animal-source-specific pathogen gene (stx1) in any water or sediment sample in any control watershed. Post-rainfall pathogen gene numbers in stream water were significantly correlated with FIB, cholesterol and coprostanol concentrations, and were most highly correlated in dairy watershed samples collected from 3 different states. Although collected across multiple states and ecoregions, animal-waste gene profiles were distinctive via discriminant analysis. Stream water gene profiles could also be discriminated by the watershed animal type. Although pathogen genes were not abundant in stream water or streambed samples, PCR on enrichments indicated that many genes were from viable organisms, including several (shiga-toxin producing or enterotoxigenic E. coli, Salmonella, vancomycin-resistant enterococci) that could potentially affect either human or animal health. Pathogen gene numbers and types in stream water samples were influenced most by animal type, by local factors such as whether animals had stream access, and by the amount of local rainfall, and not by studied watershed soil or physical characteristics. Our results indicated that stream water in small agricultural U.S. watersheds was susceptible to pathogen gene inputs under

  20. Agricultural land use alters the seasonality and magnitude of stream metabolism

    EPA Science Inventory

    Streams are active processors of organic carbon; however, spatial and temporal variation in the rates and controls on metabolism are not well quantified in streams draining intensively-farmed landscapes. We present a comprehensive dataset of gross primary production (GPP) and ec...

  1. Ecological linkages between headwaters and downstream ecosystems: Transport of organic matter, invertebrates, and wood down headwater channels

    USGS Publications Warehouse

    Wipfli, M.S.; Richardson, J.S.; Naiman, R.J.

    2007-01-01

    Headwater streams make up a large proportion of the total length and watershed area of fluvial networks, and are partially characterized by the large volume of organic matter (large wood, detritus, and dissolved organic matter) and invertebrate inputs from the riparian forest, relative to stream size. Much of those inputs are exported to downstream reaches through time where they potentially subsidize river communities. The relative rates, timing, and conversion processes that carry inputs from small streams to downstream reaches are reasonably well quantified. For example, larger particles are converted to smaller particles, which are more easily exported. Also, dissolved organic matter and surface biofilms are converted to larger particles which can be more easily intercepted by consumers. However, the quality of these materials as it affects biological activity downstream is not well known, nor is the extent to which timing permits biological use of those particles. These ecological unknowns need to be resolved. Further, land uses may disrupt and diminish material transport to downstream reaches by removing sources (e.g., forest harvest), by affecting transport and decomposition processes (e.g., flow regulation, irrigation, changes in biotic communities), and by altering mechanisms of storage within headwaters (e.g., channelization). We present conceptual models of energy and nutrient fluxes that outline small stream processes and pathways important to downstream communities, and we identify informational gaps that, if filled, could significantly advance the understanding of linkages between headwater streams and larger rivers. The models, based on empirical evidence and best professional judgment, suggest that navigable waters are significantly influenced by headwater streams through hydrological and ecological connectivities, and land use can dramatically influence these natural connectivities, impacting downstream riverine ecosystems. ?? 2007 American Water

  2. Identifying green infrastructure BMPs for reducing nitrogen export to a Chesapeake Bay agricultural stream: model synthesis and extension of experimental data

    EPA Science Inventory

    Background/Question/Methods The effectiveness of riparian forest buffers and other green infrastructure for reducing nitrogen export to agricultural streams has been well described experimentally, but a clear understanding of process-level hydrological and biogeochemical control...

  3. USE OF MACROINVERTEBRATE METRICS TO DIFFERENTIATE BETWEEN THE EFFECTS OF DECREASED CANOPY AND INCREASED EMBEDDEDNESS IN STREAMS IN DRAINING AGRICULTURAL CATCHMENTS

    EPA Science Inventory

    Reduced canopy as a result of lost riparian vegetation and increased substrate embeddedness as a result of greater inputs of the fine sediments are two environmental stressor gradients that often covary in streams draining agricultural catchments. An understanding of relationship...

  4. Identifying pathways and processes affecting nitrate and orthophosphate inputs to streams in agricultural watersheds

    USGS Publications Warehouse

    Tesoriero, A.J.; Duff, J.H.; Wolock, D.M.; Spahr, N.E.; Almendinger, J.E.

    2009-01-01

    Understanding nutrient pathways to streams will improve nutrient management strategies and estimates of the time lag between when changes in land use practices occur and when water quality effects that result from these changes are observed. Nitrate and orthophosphate (OP) concentrations in several environmental compartments were examined in watersheds having a range of base flow index (BFI) values across the continental United States to determine the dominant pathways for water and nutrient inputs to streams. Estimates of the proportion of stream nitrate that was derived from groundwater increased as BFI increased. Nitrate concentration gradients between groundwater and surface water further supported the groundwater source of nitrate in these high BFI streams. However, nitrate concentrations in stream-bed pore water in all settings were typically lower than stream or upland groundwater concentrations, suggesting that nitrate discharge to streams was not uniform through the bed. Rather, preferential pathways (e.g., springs, seeps) may allow high nitrate groundwater to bypass sites of high biogeochemical transformation. Rapid pathway compartments (e.g., overland flow, tile drains) had OP concentrations that were typically higher than in streams and were important OP conveyers in most of these watersheds. In contrast to nitrate, the proportion of stream OP that is derived from ground water did not systematically increase as BFI increased. While typically not the dominant source of OP, groundwater discharge was an important pathway of OP transport to streams when BFI values were very high and when geochemical conditions favored OP mobility in groundwater. Copyright ?? 2009 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

  5. Management of sediment and erosion processes in boreal headwaters affected by peatland drainage

    NASA Astrophysics Data System (ADS)

    Marttila, H.; Tammela, S.; Kløve, B.

    2009-04-01

    Peatland drainage for forestry, agriculture, peat harvesting and urban infrastructure has been altered landscape in Finland. Pristine peatlands and headwaters provide important hydrological and ecological functions that can be lost after drainage. The drainage has resulted in increase of forest resources but also negative environmental effects including changes in runoffs, erosion processes, siltation and eutrophication. The changes that can occur after drainage are, however, complex and must be better understood if the negative impacts of drainage are to be reduced or prevented. Especially erosion and transport processes of organic peat sediment are not well understood (Marttila and Kløve, 2008). Methods for controlling the sediment load include erosion and transport control practices in the catchment area (Marttila and Kløve, 2009; Tammela et al. 2009). The presentation/poster will present methods and preliminary results project from Northern Finland. The issues especially covered are sediment erosion and transport and methods to restore and reduce impacts of peatland drainage in boreal headwaters. Keywords: sediment transport, erosion, peatland drainage, organic and inorganic sediment, stream and catchment restoration, management, environment References: Marttila, H. and Kløve. B. 2008. Erosion and delivery of deposited peat sediment. Water Resources Research. 44 (6). Marttila, H. Kløve. B. 2009. Retention of sediment and nutrient loads with peak runoff control. Journal of Irrigation and Drainage Engineering (in press). Tammela, S. Marttila, H. and Kløve. B. 2009. Effect and design of an underminer structure on flow distribution and local bed topography (submitted).

  6. Stream ecosystem integrity is impaired by logging and shifting agriculture in a global megadiversity center (Sarawak, Borneo).

    PubMed

    Jinggut, Tajang; Yule, Catherine M; Boyero, Luz

    2012-10-15

    In common with most of Borneo, the Bakun region of Sarawak is currently subject to heavy deforestation mainly due to logging and, to a lesser extent, traditional slash-and-burn farming practices. This has the potential to affect stream ecosystems, which are integrators of environmental change in the surrounding terrestrial landscape. This study evaluated the effects of both types of deforestation by using functional and structural indicators (leaf litter decomposition rates and associated detritivores or 'shredders', respectively) to compare a fundamental ecosystem process, leaf litter decomposition, within logged, farmed and pristine streams. Slash-and-burn agricultural practices increased the overall rate of decomposition despite a decrease in shredder species richness (but not shredder abundance) due to increased microbial decomposition. In contrast, decomposition by microbes and invertebrates was slowed down in the logged streams, where shredders were less abundant and less species rich. This study suggests that shredder communities are less affected by traditional agricultural farming practices, while modern mechanized deforestation has an adverse effect on both shredder communities and leaf breakdown.

  7. Point-source effects on N and P uptake in a forested and an agricultural Mediterranean streams.

    PubMed

    Merseburger, Gora; Martí, Eugènia; Sabater, Francesc; Ortiz, Jesús D

    2011-02-01

    We examined the effect of point-source inputs from wastewater treatment plants (WWTP) on in-stream uptake of ammonium, nitrate and phosphate and compared it between two streams draining catchments with contrasting land use. The selected streams were La Tordera and Gurri (NE Spain), draining a forest- and an agriculture-dominated catchment, respectively. In each stream, we compared nutrient uptake metrics, estimated from nutrient additions, between two reaches located upstream and downstream of a WWTP input. Measurements were done on 8-9 dates during 2002-2003. In La Tordera, the point-source increased concentrations of all studied nutrients; whereas in Gurri, this effect was less evident. Point-source effects on nutrient uptake differed between the two streams, and among solutes. In La Tordera, uptake lengths (S(w)) of ammonium and phosphate averaged hundreds of meters above the point-source, and increased (i.e., decreased uptake efficiency) 4 and 5 times, respectively, below the point-source. S(w) of nitrate was ≥2km regardless of reach location. In Gurri, S(w) of all studied nutrients was within the km range in the two reaches. In this stream, diffuse nutrient inputs from adjacent fields may overwhelm the local effect of the point-source input. Uptake velocities (v(f)) of the studied nutrients ranged between 10EXP(-6) and 10EXP(-4)m/s in the two streams, and were similar between the two reaches in each stream. However, phosphate v(f) decreased under increasing concentrations following a power function. This trend remained significant when combining our results with those compiled from literature, suggesting the efficiency loss response may be a general trend for phosphate across streams. The relative increases in uptake rates (U) below the point-source were proportional to the relative point-source contribution to downstream nutrient loads, especially for ammonium and nitrate. However, the increases in U were not enough to compensate for the increases in

  8. A synoptic survey of ecosystem services from headwater catchments in the United States

    EPA Science Inventory

    We combined data collected from 568 headwater streams as a part of the US Environmental Protection Agency’s National Rivers and Streams Assessment (NRSA) with catchment attributes related to the production of the ecosystem services of water supply, carbon, nitrogen, and phosphoru...

  9. Impacts of Wood Additions on Dissolved and Particulate Nutrient Retention in an Agriculturally Impacted Stream: A Multi-Tracer Injection Study at Whatawhata, New Zealand

    NASA Astrophysics Data System (ADS)

    Drummond, J. D.; Wright-Stow, A.; Nagels, J.; Quinn, J.; Franklin, P.; Packman, A. I.

    2014-12-01

    Wood is a key component in forested streams, playing an important ecological and physical role in creating step-pool profiles, enhancing habitat heterogeneity, retaining organic matter, and changing water velocity. Wood additions can increase surface water-groundwater exchange, increasing in-stream residence times by slowing water velocities and providing high depositional areas for fine particles (i.e. particulate nutrients C, N, P). Thus, wood additions may create biogeochemical hotspots in streams that allow greater potential for local nutrient cycling and processing. The objectives of this research were to determine if added wood enhances in-stream heterogeneity, results in more complex flow paths, increases natural retention of further organic matter and changes geomorphic characteristics of the stream reach. We conducted a conservative solute and fluorescent fine particle tracer injection study in an agriculturally impacted stream with emplaced wood additions to estimate in-stream retention times in the Whatawhata catchment, North Island of New Zealand. Although similar solute peak concentrations were observed at the different in-stream sampling sites, increased retention was observed near to the wood. Both fine particle deposition and retention time was increased near the emplaced log. Fine particles were also analyzed in situ in sediment and biofilms on cobbles throughout the stream reach following the injection. A direct positive correlation was observed between cobble biofilm biomass and particle accumulation within this retention area. In general, the addition of wood to these agriculturally impacted streams enhanced hydraulic complexity and increased the retention of solute and fine particles.

  10. [Impact of rice agriculture on nitrogen and phosphorus exports in streams in hilly red soil earth region of central subtropics].

    PubMed

    Song, Li-Fang; Wang, Yi; Wu, Jin-Shui; Li, Yong; Li, Yu-Yuan; Meng, Cen; Li, Hang; Zhang, Man-Yi

    2014-01-01

    The research selected the Tuojia catchment and Jianshan catchment in Changsha County, Hunan Province, to comparatively study the effects of rice agriculture on the nitrogen and phosphorus concentrations and exports in streams in the typical agricultural catchments of the hilly red soil earth region. The monitoring of 16 months suggested that, there was a moderate stream nutrient pollution in both Tuojia and Jianshan catchments, especially for nitrogen pollution. Comparing the two catchments, the nitrogen and phosphorus concentrations were higher and the water quality was worse in the Tuojia catchment than that in the Jianshan catchment. From the nutrient composition of view, ammonia nitrogen was the main species of total nitrogen in the Tuojia catchment (accounting for 58.5% of total nitrogen), while it was nitrate nitrogen in the Jianshan catchment (accounting for 76. 1% of total nitrogen). The proportion of dissolved phosphorus in total phosphorus was 47. 1% in the Tuojia catchment, higher than the proportion of 37.5% in the Jianshan catchment. From temporal variations of nutrient dynamics of view, concentrations of all forms of nitrogen were higher during January to February and in July, respectively, and total phosphorus and dissolved phosphorus were higher during May to June and during October to December. Since the stream discharge in the catchments concentrated during the rice growing period from April to October, the higher nutrient concentrations during the period suggested potential risks of nitrogen and phosphorus losses. The total nitrogen mass flux was 1.67 kg x (hm2 x month)(-1) and TP was 0.06 kg x (hm2 x month)(-1) in the Tuojia catchment, which were greater than the 0.44 kg x (hm2 x month)(-1) and 0.02 kg x (hm2 x month)(-1) in the Jianshan catchment. Given the similar climate, geomorphology, soil type and cultivation patterns but the different area proportion of rice agriculture between two catchments, results suggested that, under the traditional

  11. Estimated agricultural pesticide use for Southeast Stream-Quality Assessment, 2014

    USGS Publications Warehouse

    Baker, Nancy T.

    2015-12-01

    This report provides estimates of annual agricultural use of 262 pesticide compounds for counties and selected watersheds in parts of eight southeastern States for 2014. Estimates of county- and watershed-level annual agricultural pesticide use are provided as downloadable, tab-delimited files for both EPest-high and EPest-low.

  12. Using Biosurfactants Produced from Agriculture Process Waste Streams to Improve Oil Recovery in Fractured Carbonate Reservoirs

    SciTech Connect

    Stephen Johnson; Mehdi Salehi; Karl Eisert; Sandra Fox

    2009-01-07

    This report describes the progress of our research during the first 30 months (10/01/2004 to 03/31/2007) of the original three-year project cycle. The project was terminated early due to DOE budget cuts. This was a joint project between the Tertiary Oil Recovery Project (TORP) at the University of Kansas and the Idaho National Laboratory (INL). The objective was to evaluate the use of low-cost biosurfactants produced from agriculture process waste streams to improve oil recovery in fractured carbonate reservoirs through wettability mediation. Biosurfactant for this project was produced using Bacillus subtilis 21332 and purified potato starch as the growth medium. The INL team produced the biosurfactant and characterized it as surfactin. INL supplied surfactin as required for the tests at KU as well as providing other microbiological services. Interfacial tension (IFT) between Soltrol 130 and both potential benchmark chemical surfactants and crude surfactin was measured over a range of concentrations. The performance of the crude surfactin preparation in reducing IFT was greater than any of the synthetic compounds throughout the concentration range studied but at low concentrations, sodium laureth sulfate (SLS) was closest to the surfactin, and was used as the benchmark in subsequent studies. Core characterization was carried out using both traditional flooding techniques to find porosity and permeability; and NMR/MRI to image cores and identify pore architecture and degree of heterogeneity. A cleaning regime was identified and developed to remove organic materials from cores and crushed carbonate rock. This allowed cores to be fully characterized and returned to a reproducible wettability state when coupled with a crude-oil aging regime. Rapid wettability assessments for crushed matrix material were developed, and used to inform slower Amott wettability tests. Initial static absorption experiments exposed limitations in the use of HPLC and TOC to determine

  13. Effect of climate, intra and inter-annual variability, on nutrients emission (C,N, P) in stream water: lessons from an agricultural long term observatory of the temperate zone

    NASA Astrophysics Data System (ADS)

    Gascuel-Odoux, Chantal; Remi, Dupas; Patrick, Durand; Ophélie, Fovet; Gerard, Gruau; Anne, Jaffrezic; Guillaume, Humbert; Philippe, Merot; Gu, Sen

    2016-04-01

    water. These results underline three major lack in most of our observatories: high frequency data as flood event are important for C and P emissions; multiple element approach, as very few observatories have currently C, N and P, their solute and particulate forms; climate but also soil wetness, GW fluctuations explaining biotransformation and connection between reservoirs on catchments, so that linking hydrological and biogeochimical condition is necessary to explain export. These lacks of observations is a barrier to develop process based models assessing and predicting the effect of climate on water quality. References Dupas R., Gruau G., Sen Gu, Humbert G., Jaffrezic A., Gascuel-Odoux C., 2015. Groundwater control of biogeochemical processes causing phosphorus release from riparian wetlands. Water Research 84, 307-314 Humbert G., Jaffrezic A., Fovet O., Gruau G., Durand P., 2015. Dry-season length and runoff control annual variability in stream DOC dynamics in a small, shallow groundwater-dominated agricultural watershed. Water Resources Research. Molenat J., Gascuel-Odoux C., Ruiz L., Gruau G., 2008. Role of water table dynamics on stream nitrate export and concentration in agricultural headwater. Journal of Hydrology 348, 363- 378.

  14. Biological Assessment of Urban and Agricultural Streams in the California Central Valley (Fall 2002 Through Spring 2004)

    NASA Astrophysics Data System (ADS)

    Bacey, J.; Moncada, A.

    2005-05-01

    California has over 200,000 miles of rivers and streams that are increasingly impacted from human activities. Various agencies in the state have begun to conduct bioassessment to evaluate these impacts. We conducted a pilot study to assess potential aquatic impacts of pesticides and other human activities in two urban creeks and two agricultural creeks in the fall and spring for two years (2002-04) using a modified U.S. EPA EMAP method. All creeks showed highly impacted conditions. Water quality measurements indicated below normal dissolved oxygen levels at 44% and 15% of the sites, and elevated temperatures at 70% and 73% of the urban and agricultural sites, respectively. Physical habitat scores indicated significant impacts. Diazinon and chlorpyrifos were detected at all sites (trace to 0.212 ppb). Pyrethroids were detected in water and sediment in urban sites only (trace to 27.5 ppt). High numbers of chironomidae and very low numbers of pollution intolerant species were detected in the benthic macroinvertebrate community. Urban creeks had a higher number of pollution tolerant species compared to agricultural creeks. All sites were ecologically impacted. Mulitvariate ANOVA of macroinvertebrate metrics revealed a significant difference between urban and agricultural sites (P= 0.002) and between fall and spring seasons (P=0.036).

  15. Headwater Nutrient Concentration Patterns in Response to Storm Events Across Land Use Types using In Situ Sensors

    NASA Astrophysics Data System (ADS)

    Price, A.; Wollheim, W. M.; Mulukutla, G. K.; Carey, R. O.; McDowell, W. H.

    2012-12-01

    Understanding the aquatic biogeochemical impacts of land use change and climate variability will require improved understanding of nutrient variability over temporal scales ranging from storms to seasons. New in situ sensor technology offers the prospect of efficient nutrient measurements over multiple time scales. We quantified nutrient flux patterns in response to storm events across seasons using in situ nutrient sensors deployed in headwater streams draining three land use types (forest, suburban, and agriculture) within the Lamprey River watershed, New Hampshire, between April-December 2012. We utilized two sensor suites, each consisting of a Satlantic Submersible Ultraviolet Nitrate Analyzer (NO3-N), Turner Designs C6 Multi-Sensor Platform (CDOM, Turbidity, Chl), Hydrolab MS5 (Dissolved Oxygen, pH), WET Labs Cycle P (PO4-P), and Hobo Water Level & Conductivity meters. Preliminary spring/summer comparisons at the suburban site suggest increased baseflow nitrate concentrations and decreased diurnal nitrate variability (~0.05 vs. 0.035 mg/L daily fluctuation) following leaf emergence in spring. Nitrate concentrations were diluted during storms. Hysteresis was evident, suggesting groundwater nitrate sources attributable to septic systems were diluted by surface runoff during spring storms. The agricultural stream showed similar but more extreme patterns of increasing baseflow nitrate during the summer (~2.4 to 4.1 mg/L) and dilution during storms. The compilation of a high-frequency dataset for headwater streams across seasons and land-use types will provide valuable insight into complex land use/water quality relationships in urbanizing watersheds.

  16. Development of rapid methods for measuring stream ecosystem functions in the Appalachian coal mining region: preliminary results

    EPA Science Inventory

    Headwater streams represent the majority of U.S. stream miles. As a consequence of being abundant and widespread, the alteration and loss of headwater streams may have impacts on downstream waterbodies. These streams are frequently the subject of proposed dredge and fill projects...

  17. Presence of Fungicides Used to Control Asian Soybean Rust in Streams in Agricultural Areas in the United States

    NASA Astrophysics Data System (ADS)

    Sandstrom, M. W.; Battaglin, W. A.

    2007-05-01

    Concentrations of 11 fungicides were measured in stream samples during 2 years in agricultural areas in the United States that grow predominantly corn and soybean. The fungicides are registered for control of Asian Soybean Rust (ASR), which entered the United States in 2004. Many of these fungicides were registered under an emergency exemption because evaluation of environmental risks related to their widespread use on soybeans had not been completed. Some of these fungicides are considered moderately to highly toxic to fish and aquatic invertebrates. We developed a solid-phase extraction and gas chromatography/mass spectrometry method for determining the fungicides at low concentrations (ng/L). Stream samples were collected 2 to 4 times at study areas during the late spring through fall season when fungicides are applied. Six fungicides registered for control of ASR (Phakospora pachyrhizi) in 2005 were measured in streams in Alabama, Georgia, North Carolina, South Carolina, and Mississippi during August-November, 2005. One or more fungicides were detected in 8 of the 12 streams sampled. Azoxystrobin, pyraclostrobin, propiconazole, tebuconazole, and myclobutanil were found in at least one of the 40 samples collected, while chlorothalonil was not found. Azoxystrobin was detected most frequently, in 35 percent of the samples. In 2006, five additional fungicides registered for use in control of ASR were included in the analytical method. One or more of the fungicides (azoxystrobin, pyraclostrobin, trifloxystrobin, metconazole, propiconazole, tebuconazole, tetraconazole, myclobutanil) were detected in 12 of the 16 streams sampled from areas in the South and Midwest during May-September, 2006. Azoxystrobin was detected most frequently (40 percent of the samples) and the highest concentration was 1.1 μg/L in a small predominantly cotton and soybean watershed. The highest concentrations of azoxystrobin were measured prior to the spread of ASR in 2006, and the detections

  18. Herbicides and herbicide degradation products in upper midwest agricultural streams during august base-flow conditions

    USGS Publications Warehouse

    Kalkhoff, S.J.; Lee, K.E.; Porter, S.D.; Terrio, P.J.; Thurman, E.M.

    2003-01-01

    Herbicide concentrations in streams of the U.S. Midwest have been shown to decrease through the growing season due to a variety of chemical and physical factors. The occurrence of herbicide degradation products at the end of the growing season is not well known. This study was conducted to document the occurrence of commonly used herbicides and their degradation products in Illinois, Iowa, and Minnesota streams during base-flow conditions in August 1997. Atrazine, the most frequently detected herbicide (94%), was present at relatively low concentrations (median 0.17 μg L−1). Metolachlor was detected in 59% and cyanazine in 37% of the samples. Seven of nine compounds detected in more than 50% of the samples were degradation products. The total concentration of the degradation products (median of 4.4 μg L−1) was significantly greater than the total concentration of parent compounds (median of 0.26 μg L−1). Atrazine compounds were present less frequently and in significantly smaller concentrations in streams draining watersheds with soils developed on less permeable tills than in watersheds with soils developed on more permeable loess. The detection and concentration of triazine compounds was negatively correlated with antecedent rainfall (April–July). In contrast, acetanalide compounds were positively correlated with antecedant rainfall in late spring and early summer that may transport the acetanalide degradates into ground water and subsequently into nearby streams. The distribution of atrazine degradation products suggests regional differences in atrazine degradation processes.

  19. NITRATE REMOVAL EFFECTIVENESS OF A RIPARIAN BUFFER ALONG A SMALL AGRICULTURAL STREAM IN WESTERN OREGON

    EPA Science Inventory

    We established two study sites with similar soils and hydrology but contrasting riparian vegetation along Lake Creek, an intermittent stream that drains perennial ryegrass fields in the Willamette Valley of western Oregon. One site had a non-cultivated riparian zone with a plant...

  20. GENETIC DAMAGE INDICATORS IN FISH EXPOSED TO VARYING STREAM CONDITIONS IN AN AGRICULTURAL WATERSHED

    EPA Science Inventory

    Micronucleus (MN) and single cell gel electrophoresis (SCG) measures of genetic damage in fish erythrocytes were included in an evaluation of a wide range of biological and physical stream condition parameters being developed for use in watershed and regional scale assessments. B...

  1. The impact of agricultural land use on stream chemistry in the Middle Hills of the Himalayas, Nepal

    NASA Astrophysics Data System (ADS)

    Collins, Robert; Jenkins, Alan

    1996-11-01

    The chemistry of streams draining agricultural and forested catchments in the Middle Hills of Nepal is described. Differences between mean streamwater chemistry are attributable to the effects of the terraced agriculture and land management practices. The agricultural catchments were found to exhibit higher mean concentrations of base cations (Na, Mg, K), bicarbonate, acid anions (SO 4, Cl), metals (Al, Fe) and nutrients (NO 3, PO 4). Increased base cations apparently result from tillage practices exposing fresh soil material to weathering. Increased acid anions result from inputs of inorganic fertiliser, notably ammonium sulphate, and from an apparent increase in evapotranspiration from the flooded terraces in the agricultural catchments. Increased metal concentrations may be promoted by increased weathering and erosion rates, and this is further supported by observations of dramatically higher turbidity in the streamwater draining the agricultural catchments. Higher levels of nutrients are the direct result of fertiliser input but concentrations are generally low from all catchments as a result of denitrification, indicating that eutrophication downstream is not a likely consequence of land use change. The major dynamics of water chemistry occur during the monsoon, which is also the main season for agricultural production. Mean wet season concentrations of base cations tend to be lower than in the dry season at all catchments as higher flow dilutes the relatively constant weathering input. Ammonium concentrations are higher from the agricultural catchments in the wet season as a result of direct washout of fertiliser. Detailed monitoring through storm periods at one agricultural catchment indicates that the chemistry responds very rapidly to changing flow, with cations decreasing and acid anions increasing followed by equally rapid recovery as flow recedes. Bicarbonate concentrations also decline markedly but are still sufficiently high to maintain pH near

  2. Leaf litter recycling in benthic and hyporheic layers in agricultural streams with different types of land use.

    PubMed

    Piscart, Christophe; Navel, Simon; Maazouzi, Chafik; Montuelle, Bernard; Cornut, Julien; Mermillod-Blondin, Florian; des Chatelliers, Michel Creuze; Simon, Laurent; Marmonier, Pierre

    2011-09-15

    Changes in land use and intensification of agricultural pressure have greatly accelerated the alteration of the landscape in most developed countries. These changes may greatly disturb the adjacent ecosystems, particularly streams, where the effects of pollution are amplified. In this study, we used the leaf litter breakdown rate to assess the functional integrity of stream ecosystems and river sediments along a gradient of either traditional extensive farming or a gradient of vineyard area. In the benthic layer, the total litter breakdown process integrates the temporal variability of the anthropogenic disturbances and is strongly influenced by land use changes in the catchment even though a low concentration of toxics was measured during the study period. This study also confirmed the essential role played by amphipods in the litter breakdown process. In contrast, microbial processes may have integrated the variations in available nutrients and dissolved oxygen concentrations, but failed to respond to the disturbances induced by vineyard production (the increase in pesticides and metal concentrations) during the study period. The response of microbes may not be sensitive enough for assessing the global effect of seasonal agricultural practices. Finally, the leaf litter breakdown measured in the hyporheic zone seemed mainly driven by microbial activities and was hence more affected by vertical exchanges with surface water than by land use practices. However, the breakdown rate of leaf litter in the hyporheic zone may constitute a relevant way to evaluate the impact on river functioning of any human activities that induce massive soil erosion and sediment clogging.

  3. Comparative study of transport processes of nitrogen, phosphorus, and herbicides to streams in five agricultural basins, USA

    USGS Publications Warehouse

    Domagalski, J.L.; Ator, S.; Coupe, R.; McCarthy, K.; Lampe, D.; Sandstrom, M.; Baker, N.

    2008-01-01

    Agricultural chemical transport to surface water and the linkage to other hydrological compartments, principally ground water, was investigated at five watersheds in semiarid to humid climatic settings. Chemical transport was affected by storm water runoff, soil drainage, irrigation, and how streams were linked