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Jimmy R. Williams - One of the best experts on this subject based on the ideXlab platform.
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Effects of agricultural Conservation Practices on N loads in the Mississippi-atchafalaya river basin.
Journal of Environmental Quality, 2014Co-Authors: C. Santhi, Xiuying Wang, N. Kannan, M. Di Luzio, Jay D. Atwood, J. G. Arnold, Michael J. White, L. Norfleet, R. Kellogg, Jimmy R. WilliamsAbstract:A modeling framework consisting of a farm-scale model, Agricultural Policy Environmental Extender (APEX); a watershed-scale model, Soil and Water Assessment Tool (SWAT); and databases was used in the Conservation Effects Assessment Project to quantify the environmental benefits of Conservation Practices on cropland. APEX is used to simulate Conservation Practices on cultivated cropland and Conservation Reserve Program land to assess the edge-of-field water-quality benefits. Flow and pollutant loadings from APEX are input to SWAT. SWAT simulates the remaining noncultivated land and routes flow and loads generated from noncultivated land, point sources, and cropland to the basin outlet. SWAT is used for assessing the effects of Practices on local and in-stream water-quality benefits. Each river basin is calibrated and validated for streamflow and loads at multiple gauging stations. The objectives of the current study are to estimate the effects of currently existing and additional Conservation Practices on total N (TN) loads in the Mississippi-Atchafalaya River Basin (MARB) and draw insights on TN load reductions necessary for reducing the hypoxic zone in the Gulf of Mexico. The effects of Conservation practice scenarios on local and in-stream (riverine) water quality are evaluated. Model results indicate that Conservation Practices currently on cropland have reduced the TN losses to local waters between 20 and 59% in the six river basins within MARB and the TN load discharged to the Gulf by 17%. Further water-quality improvement can be obtained in the MARB with additional Conservation treatment.
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Estimating the Effects of Agricultural Conservation Practices on Phosphorus Loads in the Mississippi-Atchafalaya River Basin
Transactions of the ASABE, 2014Co-Authors: C. Santhi, Jeffrey G. Arnold, N. Kannan, Jay D. Atwood, Robert L. Kellogg, Michael J. White, L. Norfleet, Susan X Wang, Mauro Di Luzio, Jimmy R. WilliamsAbstract:Abstract. Agriculture in the Mississippi-Atchafalaya River basin (MARB) is important in terms of both the national economy and the nutrients discharged to the basin and the Gulf of Mexico. Conservation Practices are installed on cropland to reduce the nutrient losses. A recent study by the Conservation Effects Assessment Project (CEAP) determined the effects of agricultural Conservation Practices on water quality in the MARB. A modeling framework consisting of a farm-scale model (Agricultural Policy Environmental Extender, APEX), a watershed-scale model (Soil and Water Assessment Tool, SWAT), and databases was used. APEX was used to simulate the Conservation Practices on cropland and Conservation Reserve Program (CRP) land and assess the edge-of-field water quality benefits. The predicted flow and loads from APEX were input to SWAT, and SWAT was used to simulate the watershed processes and estimate the local and instream water quality benefits. The model was used for scenario assessment after calibration and validation for streamflow and loads. Recent studies indicate that phosphorus influences the formation of the hypoxic zone in the Gulf of Mexico. The major objectives of this article are to: (1) estimate and discuss the effects of currently existing and additional Conservation Practices on total phosphorus (TP) loads in the MARB, and (2) assess how TP loads discharged by the Conservation scenarios can achieve the recommended annual P target for hypoxia reduction. Results indicated that current Conservation Practices on cropland have reduced TP losses to local waters by 13% to 52% in six basins within the MARB and reduced the TP load discharged to the Gulf of Mexico by 22%. Additional P load reduction is likely required to reach the annual P target for hypoxia reduction.
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an integrated modeling approach for estimating the water quality benefits of Conservation Practices at the river basin scale
Journal of Environmental Quality, 2014Co-Authors: C. Santhi, Xiuying Wang, N. Kannan, M. Di Luzio, J. G. Arnold, Michael J. White, Jimmy R. WilliamsAbstract:The USDA initiated the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of Conservation Practices at regional and national scales. For this assessment, a sampling and modeling approach is used. This paper provides a technical overview of the modeling approach used in CEAP cropland assessment to estimate the off-site water quality benefits of Conservation Practices using the Ohio River Basin (ORB) as an example. The modeling approach uses a farm-scale model, Agricultural Policy Environmental Extender (APEX), and a watershed scale model (the Soil and Water Assessment Tool [SWAT]) and databases in the Hydrologic Unit Modeling for the United States system. Databases of land use, soils, land use management, topography, weather, point sources, and atmospheric depositions were developed to derive model inputs. APEX simulates the cultivated cropland, Conserve Reserve Program land, and the Practices implemented on them, whereas SWAT simulates the noncultivated land (e.g., pasture, range, urban, and forest) and point sources. Simulation results from APEX are input into SWAT. SWAT routes all sources, including APEX's, to the basin outlet through each eight-digit watershed. Each basin is calibrated for stream flow, sediment, and nutrient loads at multiple gaging sites and turned in for simulating the effects of Conservation practice scenarios on water quality. Results indicate that sediment, nitrogen, and phosphorus loads delivered to the Mississippi River from ORB could be reduced by 16, 15, and 23%, respectively, due to current Conservation Practices. Modeling tools are useful to provide science-based information for assessing existing Conservation programs, developing future programs, and developing insights on load reductions necessary for hypoxia in the Gulf of Mexico.
C. Santhi - One of the best experts on this subject based on the ideXlab platform.
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Effects of agricultural Conservation Practices on N loads in the Mississippi-atchafalaya river basin.
Journal of Environmental Quality, 2014Co-Authors: C. Santhi, Xiuying Wang, N. Kannan, M. Di Luzio, Jay D. Atwood, J. G. Arnold, Michael J. White, L. Norfleet, R. Kellogg, Jimmy R. WilliamsAbstract:A modeling framework consisting of a farm-scale model, Agricultural Policy Environmental Extender (APEX); a watershed-scale model, Soil and Water Assessment Tool (SWAT); and databases was used in the Conservation Effects Assessment Project to quantify the environmental benefits of Conservation Practices on cropland. APEX is used to simulate Conservation Practices on cultivated cropland and Conservation Reserve Program land to assess the edge-of-field water-quality benefits. Flow and pollutant loadings from APEX are input to SWAT. SWAT simulates the remaining noncultivated land and routes flow and loads generated from noncultivated land, point sources, and cropland to the basin outlet. SWAT is used for assessing the effects of Practices on local and in-stream water-quality benefits. Each river basin is calibrated and validated for streamflow and loads at multiple gauging stations. The objectives of the current study are to estimate the effects of currently existing and additional Conservation Practices on total N (TN) loads in the Mississippi-Atchafalaya River Basin (MARB) and draw insights on TN load reductions necessary for reducing the hypoxic zone in the Gulf of Mexico. The effects of Conservation practice scenarios on local and in-stream (riverine) water quality are evaluated. Model results indicate that Conservation Practices currently on cropland have reduced the TN losses to local waters between 20 and 59% in the six river basins within MARB and the TN load discharged to the Gulf by 17%. Further water-quality improvement can be obtained in the MARB with additional Conservation treatment.
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Estimating the Effects of Agricultural Conservation Practices on Phosphorus Loads in the Mississippi-Atchafalaya River Basin
Transactions of the ASABE, 2014Co-Authors: C. Santhi, Jeffrey G. Arnold, N. Kannan, Jay D. Atwood, Robert L. Kellogg, Michael J. White, L. Norfleet, Susan X Wang, Mauro Di Luzio, Jimmy R. WilliamsAbstract:Abstract. Agriculture in the Mississippi-Atchafalaya River basin (MARB) is important in terms of both the national economy and the nutrients discharged to the basin and the Gulf of Mexico. Conservation Practices are installed on cropland to reduce the nutrient losses. A recent study by the Conservation Effects Assessment Project (CEAP) determined the effects of agricultural Conservation Practices on water quality in the MARB. A modeling framework consisting of a farm-scale model (Agricultural Policy Environmental Extender, APEX), a watershed-scale model (Soil and Water Assessment Tool, SWAT), and databases was used. APEX was used to simulate the Conservation Practices on cropland and Conservation Reserve Program (CRP) land and assess the edge-of-field water quality benefits. The predicted flow and loads from APEX were input to SWAT, and SWAT was used to simulate the watershed processes and estimate the local and instream water quality benefits. The model was used for scenario assessment after calibration and validation for streamflow and loads. Recent studies indicate that phosphorus influences the formation of the hypoxic zone in the Gulf of Mexico. The major objectives of this article are to: (1) estimate and discuss the effects of currently existing and additional Conservation Practices on total phosphorus (TP) loads in the MARB, and (2) assess how TP loads discharged by the Conservation scenarios can achieve the recommended annual P target for hypoxia reduction. Results indicated that current Conservation Practices on cropland have reduced TP losses to local waters by 13% to 52% in six basins within the MARB and reduced the TP load discharged to the Gulf of Mexico by 22%. Additional P load reduction is likely required to reach the annual P target for hypoxia reduction.
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an integrated modeling approach for estimating the water quality benefits of Conservation Practices at the river basin scale
Journal of Environmental Quality, 2014Co-Authors: C. Santhi, Xiuying Wang, N. Kannan, M. Di Luzio, J. G. Arnold, Michael J. White, Jimmy R. WilliamsAbstract:The USDA initiated the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of Conservation Practices at regional and national scales. For this assessment, a sampling and modeling approach is used. This paper provides a technical overview of the modeling approach used in CEAP cropland assessment to estimate the off-site water quality benefits of Conservation Practices using the Ohio River Basin (ORB) as an example. The modeling approach uses a farm-scale model, Agricultural Policy Environmental Extender (APEX), and a watershed scale model (the Soil and Water Assessment Tool [SWAT]) and databases in the Hydrologic Unit Modeling for the United States system. Databases of land use, soils, land use management, topography, weather, point sources, and atmospheric depositions were developed to derive model inputs. APEX simulates the cultivated cropland, Conserve Reserve Program land, and the Practices implemented on them, whereas SWAT simulates the noncultivated land (e.g., pasture, range, urban, and forest) and point sources. Simulation results from APEX are input into SWAT. SWAT routes all sources, including APEX's, to the basin outlet through each eight-digit watershed. Each basin is calibrated for stream flow, sediment, and nutrient loads at multiple gaging sites and turned in for simulating the effects of Conservation practice scenarios on water quality. Results indicate that sediment, nitrogen, and phosphorus loads delivered to the Mississippi River from ORB could be reduced by 16, 15, and 23%, respectively, due to current Conservation Practices. Modeling tools are useful to provide science-based information for assessing existing Conservation programs, developing future programs, and developing insights on load reductions necessary for hypoxia in the Gulf of Mexico.
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An Approach for Estimating Water Quality Benefits of Conservation Practices at the National Level
2005 Tampa FL July 17-20 2005, 2005Co-Authors: C. Santhi, Jeffrey G. Arnold, N. Kannan, M. Di Luzio, Steven R. Potter, Jay D. Atwood, Robert L. KelloggAbstract:The United States Department of Agriculture has initiated the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of Conservation Practices at the national scale. This paper provides an overview of the analytical approach being used in the CEAP national assessment to estimate off-site water quality benefits. For the assessment, a sampling and modeling approach is used. The farm-scale model Agricultural Policy/Environmental EXtender (APEX) is used to simulate Conservation Practices for cultivated cropland. Farmer surveys conducted on a subset of National Resource Inventory sample points provide information on current farming activities and Conservation Practices for APEX. Output from APEX will be input into the watershed scale model, Soil and Water Assessment Tool (SWAT) in the HUMUS (Hydrologic Unit Modeling for the United States) system for routing the pollutants to the 8-digit watershed outlet. SWAT will be calibrated and validated using the United States Geological Survey’s SPAtially Referenced Regressions On Watershed attributes (SPARROW) model output, streamflow and pollutant data. The HUMUS system simulates in-stream effects for (a) a baseline scenario with Conservation Practices and (b) an alternative scenario without Conservation Practices. The off-site water quality benefits of Conservation Practices currently in use will be determined by comparing outputs for the alternative scenario to the baseline outputs at each 8-digit watershed. Benefits will be reported as reductions in in-stream concentrations and loadings of sediment, nutrients and pesticides, and reductions in the number of days that concentrations exceed human health and ecological thresholds.
Geert R. De Snoo - One of the best experts on this subject based on the ideXlab platform.
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what s in it for me motivational differences between farmers subsidised and non subsidised Conservation Practices
Applied Psychology, 2011Co-Authors: Anne Marike Lokhorst, Henk Staats, Jerry Van Dijk, Eric Van Dijk, Geert R. De SnooAbstract:Through nature Conservation Practices, farmers can strongly enhance nature quality and biodiversity in rural areas. In this paper, the social psychological underpinnings of farmers' nature Conservation Practices are investigated using the Theory of Planned Behavior, to which the concepts of self-identity and personal norms were added. A distinction is made between nature Conservation Practices done on a non-subsidised basis and nature Conservation Practices for which farmers receive some form of remuneration from the Dutch government. Eighty-five arable farmers participated in our survey. Results show that our model explains more variance in the intention to perform non-subsidised than subsidised nature Conservation Practices. Also, the concepts of self-identity and personal norms appear to be related to the intention to perform non-subsidised, not subsidised Conservation.
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What's in it for Me? Motivational Differences between Farmers' Subsidised and Non‐Subsidised Conservation Practices
Applied Psychology, 2011Co-Authors: Anne Marike Lokhorst, Henk Staats, Jerry Van Dijk, Eric Van Dijk, Geert R. De SnooAbstract:Through nature Conservation Practices, farmers can strongly enhance nature quality and biodiversity in rural areas. In this paper, the social psychological underpinnings of farmers' nature Conservation Practices are investigated using the Theory of Planned Behavior, to which the concepts of self-identity and personal norms were added. A distinction is made between nature Conservation Practices done on a non-subsidised basis and nature Conservation Practices for which farmers receive some form of remuneration from the Dutch government. Eighty-five arable farmers participated in our survey. Results show that our model explains more variance in the intention to perform non-subsidised than subsidised nature Conservation Practices. Also, the concepts of self-identity and personal norms appear to be related to the intention to perform non-subsidised, not subsidised Conservation.
N. Kannan - One of the best experts on this subject based on the ideXlab platform.
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Effects of agricultural Conservation Practices on N loads in the Mississippi-atchafalaya river basin.
Journal of Environmental Quality, 2014Co-Authors: C. Santhi, Xiuying Wang, N. Kannan, M. Di Luzio, Jay D. Atwood, J. G. Arnold, Michael J. White, L. Norfleet, R. Kellogg, Jimmy R. WilliamsAbstract:A modeling framework consisting of a farm-scale model, Agricultural Policy Environmental Extender (APEX); a watershed-scale model, Soil and Water Assessment Tool (SWAT); and databases was used in the Conservation Effects Assessment Project to quantify the environmental benefits of Conservation Practices on cropland. APEX is used to simulate Conservation Practices on cultivated cropland and Conservation Reserve Program land to assess the edge-of-field water-quality benefits. Flow and pollutant loadings from APEX are input to SWAT. SWAT simulates the remaining noncultivated land and routes flow and loads generated from noncultivated land, point sources, and cropland to the basin outlet. SWAT is used for assessing the effects of Practices on local and in-stream water-quality benefits. Each river basin is calibrated and validated for streamflow and loads at multiple gauging stations. The objectives of the current study are to estimate the effects of currently existing and additional Conservation Practices on total N (TN) loads in the Mississippi-Atchafalaya River Basin (MARB) and draw insights on TN load reductions necessary for reducing the hypoxic zone in the Gulf of Mexico. The effects of Conservation practice scenarios on local and in-stream (riverine) water quality are evaluated. Model results indicate that Conservation Practices currently on cropland have reduced the TN losses to local waters between 20 and 59% in the six river basins within MARB and the TN load discharged to the Gulf by 17%. Further water-quality improvement can be obtained in the MARB with additional Conservation treatment.
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Estimating the Effects of Agricultural Conservation Practices on Phosphorus Loads in the Mississippi-Atchafalaya River Basin
Transactions of the ASABE, 2014Co-Authors: C. Santhi, Jeffrey G. Arnold, N. Kannan, Jay D. Atwood, Robert L. Kellogg, Michael J. White, L. Norfleet, Susan X Wang, Mauro Di Luzio, Jimmy R. WilliamsAbstract:Abstract. Agriculture in the Mississippi-Atchafalaya River basin (MARB) is important in terms of both the national economy and the nutrients discharged to the basin and the Gulf of Mexico. Conservation Practices are installed on cropland to reduce the nutrient losses. A recent study by the Conservation Effects Assessment Project (CEAP) determined the effects of agricultural Conservation Practices on water quality in the MARB. A modeling framework consisting of a farm-scale model (Agricultural Policy Environmental Extender, APEX), a watershed-scale model (Soil and Water Assessment Tool, SWAT), and databases was used. APEX was used to simulate the Conservation Practices on cropland and Conservation Reserve Program (CRP) land and assess the edge-of-field water quality benefits. The predicted flow and loads from APEX were input to SWAT, and SWAT was used to simulate the watershed processes and estimate the local and instream water quality benefits. The model was used for scenario assessment after calibration and validation for streamflow and loads. Recent studies indicate that phosphorus influences the formation of the hypoxic zone in the Gulf of Mexico. The major objectives of this article are to: (1) estimate and discuss the effects of currently existing and additional Conservation Practices on total phosphorus (TP) loads in the MARB, and (2) assess how TP loads discharged by the Conservation scenarios can achieve the recommended annual P target for hypoxia reduction. Results indicated that current Conservation Practices on cropland have reduced TP losses to local waters by 13% to 52% in six basins within the MARB and reduced the TP load discharged to the Gulf of Mexico by 22%. Additional P load reduction is likely required to reach the annual P target for hypoxia reduction.
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an integrated modeling approach for estimating the water quality benefits of Conservation Practices at the river basin scale
Journal of Environmental Quality, 2014Co-Authors: C. Santhi, Xiuying Wang, N. Kannan, M. Di Luzio, J. G. Arnold, Michael J. White, Jimmy R. WilliamsAbstract:The USDA initiated the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of Conservation Practices at regional and national scales. For this assessment, a sampling and modeling approach is used. This paper provides a technical overview of the modeling approach used in CEAP cropland assessment to estimate the off-site water quality benefits of Conservation Practices using the Ohio River Basin (ORB) as an example. The modeling approach uses a farm-scale model, Agricultural Policy Environmental Extender (APEX), and a watershed scale model (the Soil and Water Assessment Tool [SWAT]) and databases in the Hydrologic Unit Modeling for the United States system. Databases of land use, soils, land use management, topography, weather, point sources, and atmospheric depositions were developed to derive model inputs. APEX simulates the cultivated cropland, Conserve Reserve Program land, and the Practices implemented on them, whereas SWAT simulates the noncultivated land (e.g., pasture, range, urban, and forest) and point sources. Simulation results from APEX are input into SWAT. SWAT routes all sources, including APEX's, to the basin outlet through each eight-digit watershed. Each basin is calibrated for stream flow, sediment, and nutrient loads at multiple gaging sites and turned in for simulating the effects of Conservation practice scenarios on water quality. Results indicate that sediment, nitrogen, and phosphorus loads delivered to the Mississippi River from ORB could be reduced by 16, 15, and 23%, respectively, due to current Conservation Practices. Modeling tools are useful to provide science-based information for assessing existing Conservation programs, developing future programs, and developing insights on load reductions necessary for hypoxia in the Gulf of Mexico.
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An Approach for Estimating Water Quality Benefits of Conservation Practices at the National Level
2005 Tampa FL July 17-20 2005, 2005Co-Authors: C. Santhi, Jeffrey G. Arnold, N. Kannan, M. Di Luzio, Steven R. Potter, Jay D. Atwood, Robert L. KelloggAbstract:The United States Department of Agriculture has initiated the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of Conservation Practices at the national scale. This paper provides an overview of the analytical approach being used in the CEAP national assessment to estimate off-site water quality benefits. For the assessment, a sampling and modeling approach is used. The farm-scale model Agricultural Policy/Environmental EXtender (APEX) is used to simulate Conservation Practices for cultivated cropland. Farmer surveys conducted on a subset of National Resource Inventory sample points provide information on current farming activities and Conservation Practices for APEX. Output from APEX will be input into the watershed scale model, Soil and Water Assessment Tool (SWAT) in the HUMUS (Hydrologic Unit Modeling for the United States) system for routing the pollutants to the 8-digit watershed outlet. SWAT will be calibrated and validated using the United States Geological Survey’s SPAtially Referenced Regressions On Watershed attributes (SPARROW) model output, streamflow and pollutant data. The HUMUS system simulates in-stream effects for (a) a baseline scenario with Conservation Practices and (b) an alternative scenario without Conservation Practices. The off-site water quality benefits of Conservation Practices currently in use will be determined by comparing outputs for the alternative scenario to the baseline outputs at each 8-digit watershed. Benefits will be reported as reductions in in-stream concentrations and loadings of sediment, nutrients and pesticides, and reductions in the number of days that concentrations exceed human health and ecological thresholds.
M. Di Luzio - One of the best experts on this subject based on the ideXlab platform.
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Effects of agricultural Conservation Practices on N loads in the Mississippi-atchafalaya river basin.
Journal of Environmental Quality, 2014Co-Authors: C. Santhi, Xiuying Wang, N. Kannan, M. Di Luzio, Jay D. Atwood, J. G. Arnold, Michael J. White, L. Norfleet, R. Kellogg, Jimmy R. WilliamsAbstract:A modeling framework consisting of a farm-scale model, Agricultural Policy Environmental Extender (APEX); a watershed-scale model, Soil and Water Assessment Tool (SWAT); and databases was used in the Conservation Effects Assessment Project to quantify the environmental benefits of Conservation Practices on cropland. APEX is used to simulate Conservation Practices on cultivated cropland and Conservation Reserve Program land to assess the edge-of-field water-quality benefits. Flow and pollutant loadings from APEX are input to SWAT. SWAT simulates the remaining noncultivated land and routes flow and loads generated from noncultivated land, point sources, and cropland to the basin outlet. SWAT is used for assessing the effects of Practices on local and in-stream water-quality benefits. Each river basin is calibrated and validated for streamflow and loads at multiple gauging stations. The objectives of the current study are to estimate the effects of currently existing and additional Conservation Practices on total N (TN) loads in the Mississippi-Atchafalaya River Basin (MARB) and draw insights on TN load reductions necessary for reducing the hypoxic zone in the Gulf of Mexico. The effects of Conservation practice scenarios on local and in-stream (riverine) water quality are evaluated. Model results indicate that Conservation Practices currently on cropland have reduced the TN losses to local waters between 20 and 59% in the six river basins within MARB and the TN load discharged to the Gulf by 17%. Further water-quality improvement can be obtained in the MARB with additional Conservation treatment.
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an integrated modeling approach for estimating the water quality benefits of Conservation Practices at the river basin scale
Journal of Environmental Quality, 2014Co-Authors: C. Santhi, Xiuying Wang, N. Kannan, M. Di Luzio, J. G. Arnold, Michael J. White, Jimmy R. WilliamsAbstract:The USDA initiated the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of Conservation Practices at regional and national scales. For this assessment, a sampling and modeling approach is used. This paper provides a technical overview of the modeling approach used in CEAP cropland assessment to estimate the off-site water quality benefits of Conservation Practices using the Ohio River Basin (ORB) as an example. The modeling approach uses a farm-scale model, Agricultural Policy Environmental Extender (APEX), and a watershed scale model (the Soil and Water Assessment Tool [SWAT]) and databases in the Hydrologic Unit Modeling for the United States system. Databases of land use, soils, land use management, topography, weather, point sources, and atmospheric depositions were developed to derive model inputs. APEX simulates the cultivated cropland, Conserve Reserve Program land, and the Practices implemented on them, whereas SWAT simulates the noncultivated land (e.g., pasture, range, urban, and forest) and point sources. Simulation results from APEX are input into SWAT. SWAT routes all sources, including APEX's, to the basin outlet through each eight-digit watershed. Each basin is calibrated for stream flow, sediment, and nutrient loads at multiple gaging sites and turned in for simulating the effects of Conservation practice scenarios on water quality. Results indicate that sediment, nitrogen, and phosphorus loads delivered to the Mississippi River from ORB could be reduced by 16, 15, and 23%, respectively, due to current Conservation Practices. Modeling tools are useful to provide science-based information for assessing existing Conservation programs, developing future programs, and developing insights on load reductions necessary for hypoxia in the Gulf of Mexico.
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An Approach for Estimating Water Quality Benefits of Conservation Practices at the National Level
2005 Tampa FL July 17-20 2005, 2005Co-Authors: C. Santhi, Jeffrey G. Arnold, N. Kannan, M. Di Luzio, Steven R. Potter, Jay D. Atwood, Robert L. KelloggAbstract:The United States Department of Agriculture has initiated the Conservation Effects Assessment Project (CEAP) to quantify the environmental benefits of Conservation Practices at the national scale. This paper provides an overview of the analytical approach being used in the CEAP national assessment to estimate off-site water quality benefits. For the assessment, a sampling and modeling approach is used. The farm-scale model Agricultural Policy/Environmental EXtender (APEX) is used to simulate Conservation Practices for cultivated cropland. Farmer surveys conducted on a subset of National Resource Inventory sample points provide information on current farming activities and Conservation Practices for APEX. Output from APEX will be input into the watershed scale model, Soil and Water Assessment Tool (SWAT) in the HUMUS (Hydrologic Unit Modeling for the United States) system for routing the pollutants to the 8-digit watershed outlet. SWAT will be calibrated and validated using the United States Geological Survey’s SPAtially Referenced Regressions On Watershed attributes (SPARROW) model output, streamflow and pollutant data. The HUMUS system simulates in-stream effects for (a) a baseline scenario with Conservation Practices and (b) an alternative scenario without Conservation Practices. The off-site water quality benefits of Conservation Practices currently in use will be determined by comparing outputs for the alternative scenario to the baseline outputs at each 8-digit watershed. Benefits will be reported as reductions in in-stream concentrations and loadings of sediment, nutrients and pesticides, and reductions in the number of days that concentrations exceed human health and ecological thresholds.