SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Predicting sediment and phosphorus loads in the Rock River Basin using SWAT 
Authors:Kirsch, K., A. Kirsch and J.G. Arnold 
Journal:Transactions of the ASAE 
Volume (Issue):45(6) 
Article ID: 
URL (non-DOI journals):http://solimserver.geography.wisc.edu/axing/teaching/geog577/lectures/Kirsch_etal_SWAT_SedimentAndPhosphorus2002.pdf 
Broad Application Category:hydrologic & pollutant 
Primary Application Category:pollutant cycling/loss and transport 
Secondary Application Category:hydrologic assessment 
Watershed Description:9,708 km^2 Rock River, located in southeast Wisconsin, U.S. 
Calibration Summary:Annual for Windsor gauge (1989-95 for flow; 1991-95 for sediment & total P): flow r2/E = .74/.61 sediment r2/E = .82/.75 total P r2/E = .95/.07 ------------------------ 12 USGS gauges were used for evaluating annual flows (most in time period of 1989-96): r2 = .28 to .98 (9 sites: r2 > .65) 
Validation Summary:% differences reported for 8 USGS gauge sites for streamflow, sediment, and total P 
General Comments:SWAT98.1 was used to quantify P loads throughout the watershed and to assess the impacts of selected BMPs. Modifications were made to the model during the study that were incorporated into SWAT2000. Initial calibration and validation statistics are reported for two smaller subwatersheds (including the Yahara/Mendota subwateshed - Windsor gauging site); further calibration was performed using flows measured at 12 USGS gauges for the whole basin and 1999 flow, sediment, and total P validation statistics were used for validation. The total P load estimated for the baseline was 764,000 kg (41and 59% attributed to point & nonpoint sources, respectively). Five different tillage, nutrient mang., & effuent conc. (point source) scenarios resulted in total P loads ranging from 462,000 to 703,000 kg/yr. 
Abstract:The Rock River is considered degraded from excessive amounts of phosphorus. Individual programs are ongoing to reduce phosphorus from point and nonpoint sources. However, a comprehensive phosphorus management approach may prove more cost effective and beneficial. To be successful, such an approach must take into consideration phosphorus from all sources and seek geographically targeted, cost–effective, and holistic solutions. This study utilized the SWAT (Soil and Water Assessment Tool) model to quantify phosphorus sources throughout the basin and quantify impacts from the application of basin–wide BMPs. Results of this study indicate that, under existing land use and management conditions, an average annual phosphorus load of approximately 764,000 kg enters the Rock River and it tributaries. Point sources account for 41% of this value, and nonpoint sources account for 59%. Model results show that, under existing conditions, approximately 160,000 tons of sediment is delivered to the streams and surface water bodies on an average annual basis. Modeling results indicate that implementation of improved tillage practices (predominantly conservation tillage) can reduce sediment yields by almost 20%. 
Keywords:SWAT, Water quality, Hydrologic modeling, Sediment, Phosphorus