Author(s)

K. R. Mankin, P. Tuppad, D. L. Devlin, K. A. McVay & W. L. Hargrove

Abstract

The key to achieving the most cost effective water-quality protection on a watershed scale is to identify and implement practices on areas that contribute most to water-quality impairment. This stands in contrast to the typical approach, where implementation depends on volunteer adoption by landowners and managers. The goal of this paper is to present a strategic approach that identifies areas that have the greatest potential to contribute to water-quality improvement and helps focus the watershed management efforts that will produce maximum water-quality benefits on these areas. The study watershed, Smoky Hill River/Kanopolis Lake watershed in Kansas, USA, consists of almost 50% cropland, considered a major source of pollutants. The impacts of reduced tillage (RT) and edge-of-field vegetative buffers (VBS) on sediment and nutrients were evaluated using either random implementation or strategic targeting based on ranked subbasin overland sediment yield. The targeted watershed modelling approach was found to be more effective in reducing pollutant load both overland and at the watershed outlet with less area than randomly selecting areas for BMP adoption. Annual average, watershed-scale, overland pollutant yield reductions of 10% required BMP adoption on less than half the land area when targeting was used rather than random placement of BMPs. Targeting produced even greater benefits when watershed-outlet loads were considered. The benefits of targeting are greater for initial increments of BMP adoption and decrease as the proportion of BMP adoption on targeted land areas increases. Keywords: watershed restoration, basin, SWAT, conservation practices.

Keywords

watershed restoration, basin, SWAT, conservation practices.