Considering spatial distribution and deposition of sediment in lumped and semi-distributed models

The goal of this paper is to test a new semi-lumped sediment delivery concept to consider deposition. With this method, the distance between sediment source and river channel is taken into account. It is based on the assumption that sediment delivery rates (SDR-values) are related to the length of the flow path of the sediment from source area to channel. For each subwatershed an average weighted distance to the river channel can be calculated whereby cells with little or no soil erosion have a high weight. The procedure was implemented in SWAT-G (Soil and Water Assessment Tool) and calibrated and validated for two watersheds in Belgium and Germany. The results point out that the proposed method is a significant improvement of the sediment routine compared to existing lumped equations such as the MUSLE. Copyright (C) 2005 John Wiley Sons, Ltd.