US EPA

2038597 

Journal Article 

Non-Point Source Pollution Reduction by Filter Strips in Water and Soil Environment 

Gu, R; Zhao, X; Sahu, M 

2010 

226-231 

WOS:000290971900039 

Contour filter strips planted with perennial vegetation can be used to improve surface and ground water quality by reducing pollutant, such as NO(3)-N, and sediment outflow from cropland to a river or lake. Meanwhile, the filter strips of perennial grass with bio-fuel potentials also have economic benefits of producing ethanol. In this study, The Soil and Water Assessment Tool (SWAT) model was applied to the Walnut Creek Watershed to examine the effectiveness of contour strips in reducing NO(3)-N outflows from crop fields to the river or lake. Required input data include watershed topography, slope, soil type, land-use, management practices, in the watershed and climate parameters (precipitation, maximum/minimum air temperature, solar radiation, wind speed and relative humidity). Numerical experiments were conducted to identify potential subbasins in the watershed that have high water quality impact, and to examine the effects of strip size and location on NO(3)-N reduction in the subbasins under various meteorological conditions (dry, average and wet). Variable sizes of contour strips (10%, 20%, 30% and 50%, respectively, of a subbasin area) planted with perennial switchgrass were selected for simulating the effects of strip size and location on stream water quality. Simulation results showed that a filter strip having 10%-50% of the subbasin area could lead to 55%-90% NO(3)-N reduction in the subbasin during an average rainfall year. Strips occupying 10-20% of the subbasin area were found to be more efficient in reducing NO(3)-N when placed along the contour than that when placed along the river. The results of this study can assist in cost-benefit analysis and decision-making in best water resources management practices for environmental protection. 

modeling; SWAT; water quality; NO(3)-N; watershed