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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay Nontidal network (NTN) stations for the period 1985 through 2018. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). Yields (represents the mass of constituent transported from a unit area of a given watershed) are used to compare the export loads from one basin to another. Yield results are obtained by dividing the annual load (pounds) of a given constituent by the respective watershed area (acres)...
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This data release consists of the data used to develop SPAtially Referenced Regression On Watershed(SPARROW) attributes models for estimating loads of total phosphorus and total nitrogen in Tennessee streams. These data support the publication containing the Tennessee SPARROW models results (Hoos and others, 2019) and include model input used in the South Atlantic-Gulf Drainages and Tennessee River Basin (SAGT) nutrient SPARROW models (Hoos and McMahon, 2009; Garcia and others, 2011) as well as model input for river basins in Tennessee not included in the domain of the published SAGT SPARROW models. Also included in this data release are model coefficients, the software required to execute the Tennessee SPARROW...
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This data release consists of the data used to develop SPAtially Referenced Regression On Watershed(SPARROW) attributes models for estimating loads of total phosphorus and total nitrogen in Tennessee streams. These data support the publication containing the Tennessee SPARROW models results (Hoos and others, 2019) and include model input used in the South Atlantic-Gulf Drainages and Tennessee River Basin (SAGT) nutrient SPARROW models (Hoos and McMahon, 2009; Garcia and others, 2011) as well as model input for river basins in Tennessee not included in the domain of the published SAGT SPARROW models. Also included in this data release are model coefficients, the software required to execute the Tennessee SPARROW...
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring Network (RIM) stations for the period 1985 through 2017. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment that was exported from each of the RIM watersheds.
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This data release consists of the data used to develop SPAtially Referenced Regression On Watershed(SPARROW) attributes models for estimating loads of total phosphorus and total nitrogen in Tennessee streams. These data support the publication containing the Tennessee SPARROW models results (Hoos and others, 2019) and include model input used in the South Atlantic-Gulf Drainages and Tennessee River Basin (SAGT) nutrient SPARROW models (Hoos and McMahon, 2009; Garcia and others, 2011) as well as model input for river basins in Tennessee not included in the domain of the published SAGT SPARROW models. Also included in this data release are model coefficients, the software required to execute the Tennessee SPARROW...
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring Network (RIM) stations for the period 1985 through 2018. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment that was exported from each of the RIM watersheds.
The purpose of my research group is to develop new methods and applications of environmental isotopes to solve problems of national importance. In specific, the overall goal is to use environmental isotopes, combined with other biogeochemical measurements and hydrologic and biogeochemical modeling, to increase our understanding of biogeochemical and hydrological processes, nutrient and organic matter sources, subsurface flowpaths, and water age distributions in diverse environments. Many of our studies piggyback on the sampling efforts of major monitoring programs to investigate causes of hypoxia and food web problems. Our work provides critical scientific support for these monitoring programs. A long-term career...
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay Nontidal Network (NTN) stations for the period 1985 through 2016. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment that was exported from each of the NTN watersheds. To determine the trend in loads, the annual load results are flow normalized to integrate out the year-to-year variability in river discharge....
Evaluate the hydrologic and geochemical processes that control nitrate fluxes in agricultural settings. Important questions remain about the overall regional and global importance of groundwater nitrogen fluxes, denitrification (microbial reduction of NO 3 − to N 2), and the sources of electron donors contributing to this microbial reaction. Studies are needed that apply robust methods for measuring nitrogen fluxes and denitrification among multiple sites to evaluate important factors affecting N fluxes. These results, in combination with novel methods for efficient estimation of fluxes in groundwater, facilitate estimates of N fluxes in across large regions such as the Corn Belt. Quantify the effects of complex...
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Estimated nitrogen delivered to the estuaries along the Gulf of Mexico (U.S. only). Delivered load is the amount of nitrogen estimated using USGS's SPARROW model to be delivered from the upstream drainage basin to each of the estuaries draining into the Gulf of Mexico. These estimates are corrected to match monitoring load data at the most downstream monitoring site available. Units are in metric tons per year.
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring Network (RIM) stations for the period 1985 through 2017. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment that was exported from each of the RIM watersheds. To determine the trend in loads, the annual load results are flow normalized to integrate out the year-to-year variability...
For the first time in history a short pulse of water was intentionally released for environmental purposes in April–May 2014 into the final 160 km stretch of the Colorado River, south of the Mexican border. During this pulse the sources and turnover of dissolved nutrients (nitrate, ammonium, phosphate, silicate and carbon), particulate organic matter, along with stable isotopes of suspended particulate carbon and nitrogen, were studied. The river water, as it flowed along the dry riverbed became rapidly depleted in N-NO3(from 21 to 0.5 μmol L−1), while dissolved organic carbon of terrestrial C3plant origin became depleted in13C and thus more negative δ13CDOCvalues. At the confluence with the Hardy River, the pulsed...
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The Transboundary Aquifer Assessment Act was established to systematically assess priority aquifers along the U.S.-Mexico international boundary. The priority aquifers that were specified include the Hueco-Mesilla Bolsons aquifer in Texas and New Mexico and its counterpart in Mexico, the Conejos-Medanos Aquifer system, and the Santa Cruz and San Pedro aquifers in Arizona (Texas Water Development Board, 2019). The Transboundary Aquifer Assessment Program (TAAP) was started in 2009 and is a collaborative effort between the U.S. Geological Survey, Arizona Water Resources Research Center, New Mexico Water Resources Research Institute, and the Texas Water Resources Institute (U.S. Geological Survey, 2018) to better understand...
Griffith, Michael B., F. Bernard Daniel, Matthew A. Morrison, Michael E. Troyer, James M. Lazorchak, and Joseph P. Schubauer-Berigan, 2009. Linking Excess Nutrients, Light, and Fine Bedded Sediments to Impacts on Faunal Assemblages in Headwater Agricultural Streams. Journal of the American Water Resources Association (JAWRA) 45(6):1475-1492. Abstract: Biological impairments in streams are typically defined by regulatory agencies in terms of altered invertebrate or fish assemblages. While nutrients, canopy cover, and sediment fines contribute to these impairments, these stressors are often defined, at least in part, by their impacts on periphyton. Path analysis can extend these assessments to impacts on invertebrates...
The SPARROW Decision Support System (SPARROW DSS) provides access to national, regional, and basin-wide SPARROW models ( Spatially Referenced Regressions On Watershed attributes) for water managers, researchers, and the general public. Models are available for a variety of water-quality constituents and time periods. For each model, users can: Map predictions of long-term average water-quality conditions (loads, yields, concentrations) and source contributions by stream reach and catchment Track transport to downstream receiving waters, such as reservoirs and estuaries Evaluate management source-reduction scenarios Overlay land use, shaded relief, street-level data, states, counties, and hydrologic units. Differences...
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This report documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the North Delta in the Sacramento-San Joaquin River Delta of California, USA. The data set includes nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, and chlorophyll. Data-collection were conducted over one day in July 2017 when continuous monitoring stations detected elevated chlorophyll concentration and decreasing nitrate concentrations.
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The data release contains data for the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the North Delta in the Sacramento-San Joaquin River Delta of California, USA. The data set includes nitrate, ammonium, phosphate, dissolved organic carbon, temperature, conductivity, dissolved oxygen, turbidity, and chlorophyll. Data-collection cruises were conducted over two days in March 2017 during a high flow event when Sacramento Valley flood waters inundate the Yolo Bypass.
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay Nontidal Network (NTN) stations for the period 1985 through 2020. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment that was exported from each of the NTN watersheds. The file containing annual loads for all applicable NTN monitoring stations is provided in the "Attached Files" section. First posted: July...
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Nitrogen, phosphorus, and suspended-sediment loads, and changes in loads, in major rivers across the Chesapeake Bay watershed have been calculated using monitoring data from the Chesapeake Bay River Input Monitoring (RIM) Network stations for the period 1985 through 2021. Nutrient and suspended-sediment loads and changes in loads were determined by applying a weighted regression approach called WRTDS (Weighted Regression on Time, Discharge, and Season). The load results represent the total mass of nitrogen, phosphorus, and suspended sediment that was exported from each of the RIM watersheds.


map background search result map search result map Nutrients - Total Delivered Load - Nitrogen - Estuarine Chesapeake Bay Nontidal Network 1985-2016: Short- and long-term trends Transboundary Aquifer Assessment Program—Water-Quality Data from Groundwater Wells in the Hueco Bolson near El Paso, Texas, August 2016—June 2017 Chesapeake Bay River Input Monitoring Network 1985-2017: Annual loads Chesapeake Bay River Input Monitoring Network 1985-2017: Short- and long-term trends Names of 10-digit hydrologic unit code (HUC10) watersheds in the state of Tennessee Shapefile of stream reaches used in Tennessee SPARROW models Chesapeake Bay River Input Monitoring Network 1985-2018: WRTDS input data Scenario calculator for Tennessee SPARROW nutrient models Chesapeake Bay Nontidal Network 1985-2018: Average annual yields Assessment of nutrients and water-quality constituents at the Sacramento-San Joaquin River Confluence during a phytoplankton bloom in July 2017 Assessment of nutrients and water-quality constituents in the North Delta during Yolo Bypass flooding events in March 2017 Chesapeake Bay Nontidal Network 1985-2020: Annual loads (ver. 2.0, January 2023) Chesapeake Bay River Input Monitoring Network 1985-2021: WRTDS output data Assessment of nutrients and water-quality constituents in the North Delta during Yolo Bypass flooding events in March 2017 Transboundary Aquifer Assessment Program—Water-Quality Data from Groundwater Wells in the Hueco Bolson near El Paso, Texas, August 2016—June 2017 Assessment of nutrients and water-quality constituents at the Sacramento-San Joaquin River Confluence during a phytoplankton bloom in July 2017 Chesapeake Bay Nontidal Network 1985-2016: Short- and long-term trends Chesapeake Bay River Input Monitoring Network 1985-2017: Annual loads Chesapeake Bay River Input Monitoring Network 1985-2017: Short- and long-term trends Chesapeake Bay Nontidal Network 1985-2020: Annual loads (ver. 2.0, January 2023) Chesapeake Bay River Input Monitoring Network 1985-2018: WRTDS input data Chesapeake Bay Nontidal Network 1985-2018: Average annual yields Chesapeake Bay River Input Monitoring Network 1985-2021: WRTDS output data Nutrients - Total Delivered Load - Nitrogen - Estuarine Names of 10-digit hydrologic unit code (HUC10) watersheds in the state of Tennessee Shapefile of stream reaches used in Tennessee SPARROW models Scenario calculator for Tennessee SPARROW nutrient models