Prediction of Ephemeral Gully Locations: Case Studies In Mississippi and Black Soil Region of China.

Ephemeral gully erosion is an important soil erosion process in sloping agricultural landscapes. The Compound Topographic Index (CTI) method has been used to predict ephemeral gully locations based upon topography alone. The CTI uses the contributing area, slope gradient, and planform curvature to predict a gully location. This study investigated the effectiveness of the CTI and methods of incorporating landuse, management and soil properties for improving the CTI approach. Spatial distributions of ephemeral gullies were identified in several watersheds in the US and the Black Soil Region of China. The surface topography was measured with differential GPS, along with ephemeral gully locations and size, landuse, management and selected soil properties. The CTI method for ephemeral gully location prediction was tested and a method to incorporate soil and landuse properties to strengthen the current CTI method is proposed. The results will improve the understanding of ephemeral gully initiation and methods of predicting ephemeral gully locations.