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Impact of climate change on streamflow in the Upper Mississippi River Basin is evaluated by use of a regional climate model (RCM) coupled with a hydrologic model, Soil and Water Assessment Tool (SWAT). The RCM we used resolves, at least partially, some fine-scale dynamical processes that are important contributors to precipitation in this region and that are not well simulated by global models. The SWAT model was calibrated and validated against measured streamflow data using observed weather data and inputs from the U.S. Environmental Protection Agency Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) geographic information systems/database system. Combined performance of SWAT and RCM was...
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This paper provides estimates of the cost associated with inducing substantial conversion of land from production of traditional crops to switchgrass and its potential environmental consequences. Higher traditional crop prices due to increased demand for corn from the ethanol industry has increased the relative advantage that row crops have over switchgrass. Results indicate that farmers will convert to switchgrass production only with significant conversion subsidies. Potential environmental consequences of this conversion were analyzed using three stylized landscape usage scenarios, one with an entire conversion of a watershed to switchgrass production, a second with the entire watershed planted to continuous...
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Nonpoint source pollution in intensively managed agricultural landscapes is of great concern to the general population, farmers and policymakers, as it impacts local water quality and can have large downstream effects, as in the case of hypoxia in the Gulf of Mexico. In this study, we outline a methodology to simultaneously assess economic costs and water quality benefits associated with the hypothetical placement of a broad set of conservation practices. The study, performed for the Iowa Department of Natural Resources, assesses thirteen major subbasins in Iowa by interfacing economic models with the Soil and Water Assessment Tool model. The conservation practices analyzed include land set-aside, terraces, grassed...
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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)...
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We use Soil and Water Assessment Tool (SWAT) when driven by observations and results of climate models to evaluate hydrological quantities, including streamflow, in the Upper Mississippi River Basin (UMRB) for 1981--2003 in comparison to observed streamflow. Daily meteorological conditions used as input to SWAT are taken from (1) observations at weather stations in the basin, (2) daily meteorological conditions simulated by a collection of regional climate models (RCMs) driven by reanalysis boundary conditions, and (3) daily meteorological conditions simulated by a collection of global climate models (GCMs). Regional models used are those whose data are archived by the North American Regional Climate Change Assessment...
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