SWAT Literature Database for Peer-Reviewed Journal Articles

Title:Water quality effects of simulated conservation practice scenarios in the Little River Experimental watershed 
Authors:Cho, J., G.Vellidis, D.D. Bosch, R. Lowrance and T. Strickland 
Journal:Journal of Soil and Water Conservation 
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Broad Application Category:hydrologic & pollutant 
Primary Application Category:BMP assessment 
Secondary Application Category:pollutant cycling/loss and transport 
Watershed Description:334 km^2 Little River Experimental in southern Georgia, USA 
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Abstract:The goal of this study was to evaluate the water quality effects of alternative conservation practice scenarios using the SWAT (Soil and Water Assessment Tool) model in the Little River Experimental watershed, a representative coastal plain watershed located in southern Georgia. We simulated the water quality effect of two suites of upland conservation practices (CPs)—one targeting erosion and the other targeting nutrients. We also simulated the impact of riparian forest buffers. Finally, we evaluated three different management scenarios for implementing the upland CPs: using a random approach, using subwatershed stream order as a prioritization criterion, and using subwatershed nonpoint source pollutant load as a prioritization criterion. The study showed that using subwatershed nonpoint source pollutant load as a prioritization criterion resulted in the most rapid water quality improvements. This improvement in water quality was nonlinear, while the other implementation schemes yield linear returns. Full implementation of the suite of CPs targeting erosion resulted in the greatest reductions of sediment (54.7%) and total phosphorus (55.9%) loads from upland crop areas. Full implementation of the suite of CPs targeting nutrient reduction resulted in the greatest total nitrogen load reduction (10.3%). Overall, an intact riparian forest buffer offered the most comprehensive reduction of nonpoint source pollutant loads—20.5% for sediment, 19.5% for total phosphorus, and 7.0% for total nitrogen. Simulation results indicate that at the current time, the single greatest contributor to nonpoint source pollutant reduction in the Little River Experimental watershed may be the current level of riparian forest cover. 
Keywords:alternative scenarios, buffer, conservation practices, nutrients, riparian forest, sediment, Soil and Water Assessment Tool (SWAT), water quality