Development of Erosion Hotspots for a Watershed

The loss of topsoil in the United States has resulted in low crop yield, reduction of reservoir capacity, cost increase of water treatment, and detrimental effects on aquatic life and wildlife habitats. An initial step for taking conservation measures in any watershed is to identify locations where erosion protection measures are needed. Applying the Revised Universal Soil Loss Equation (RUSLE) and a geographic information system (GIS), this study attempts to locate the most erodible locations, namely erosion hotspots, for a watershed. Using GIS, the watershed is divided into 25x25-m grids and the RUSLE, including rainfall-runoff erosivity factor, soil erodibility factor, combined slope length and slope steepness factor, cover management factor, and support practice factor, is applied for the estimation of soil erosion potential for each grid cell. By ranking these grid values of erosion potential in a descending order, the top 1% and corresponding locations are defined as the erosion hot spots, which can be expressed in an erosion hotspot map. Applying this method to the Charles Mill Lake Watershed in Ohio, it is found that the erosion hotspots for the watershed under investigation are generally located in the areas of strip mine and cropland/pasture. (C) 2013 American Society of Civil Engineers.