Skip to main content
USGS - science for a changing world

Arnold, J. G.

The purpose of the Conservation Effects Assessment Project (CEAP) cropland national assessment is to quantify the environmental benefits of conservation programs at the regional and national levels, which include both onsite and instream water quality benefits. Modeling is an effective tool for environmental assessment at the regional and national scale due to the complexities in nature at this scale. Two simulation models, the Agricultural Policy Environmental extender (APEX) and the Soil and Water Assessment Tool (SWAT), were used for the CEAP cropland national assessment. A subset of National Resources Inventory (NRI) sample points was selected to serve as "representative fields" for the CEAP cropland survey...
Nitrate nitrogen (NO3-N) enriched water originates from subsurface drains or "tiles" that underlay many fields in the Corn Belt and is the primary source of NO3-N to surface waters in this region. To better assess the fate and transport of nutrients, such as NO3-N, the tile drain and pothole components of SWAT (Soil and Water Assessment Tool) were enhanced and modified in the previous component of this study. In this study, the environmental and economic impacts of various best management practice (BMP) scenarios often adopted by local farmers to reduce sediment and nutrient loadings (in particular NO3-N) were evaluated using the modified SWAT (SWAT-M) and FEM (Farm-level Economic Model) models. Measured values...
The U.S. Environmental Protection Agency (USEPA) Office of Pesticide Programs (OPP) has completed an evaluation of three watershed-scale simulation models for potential use in Food Quality Protection Act pesticide drinking water exposure assessments. The evaluation may also guide OPP in identifying computer simulation tools that can be used in performing aquatic ecological exposure assessments. Models selected for evaluation were the Soil Water Assessment Tool (SWAT), the Nonpoint Source Model (NPSM), a modified version of the Hydrologic Simulation Program-Fortran (HSPF), and the Pesticide Root Zone Model-Riverine Water Quality (PRZM-RIVWQ) model. Simulated concentrations of the pesticides atrazine, metolachlor,...
The Soil and Water Assessment Tool (SWAT) model was used to assess the effects of potential future climate change on the hydrology of the Upper Mississippi River Basin (UMRB). Calibration and validation of SWAT were performed using monthly stream flows for 1968-1987 and 1988-1997, respectively. The R super(2) and Nash-Sutcliffe simulation efficiency values computed for the monthly comparisons were 0.74 and 0.69 for the calibration period and 0.82 and 0.81 for the validation period. The effects of nine 30-year (1968 to 1997) sensitivity runs and six climate change scenarios were then analyzed, relative to a scenario baseline. A doubling of atmospheric C0 sub(2)to 660 ppmv (while holding other climate variables constant)...
ScienceBase brings together the best information it can find about USGS researchers and offices to show connections to publications, projects, and data. We are still working to improve this process and information is by no means complete. If you don't see everything you know is associated with you, a colleague, or your office, please be patient while we work to connect the dots. Feel free to contact sciencebase@usgs.gov.