Evaluation of an interrill soil erosion model using laboratory catchment data

Physically based soil erosion simulation models require input parameters of soil detachment and sediment transport owing to the action and interaction s of both raindrops and overland flow. A simple interrill soil water transp ort model is applied to a laboratory catchment to investigate the applicati on of raindrop detachment and transport in interrill areas explicitly. A co ntrolled laboratory rainfall simulation study with slope length simulation by flow addition was used to assess the raindrop detachment and transport o f detached soil by overland flow in interrill areas. Artificial rainfall of moderate to high intensity was used to simulate intense rain storms. Howev er, experiments were restricted to conditions where rilling and channelling did not occur and where overland flow covered most of the surface. A simpl e equation with a rainfall intensity term for raindrop detachment, and a si mple sediment transport equation with unit discharge and a slope term were found to be applicable to the situation where clear water is added at the u pper end of a small plot to simulate increased slope length. The proposed g eneric relationships can be used to predict raindrop detachment and the sed iment transport capacity of interrill flow and can therefore contribute to the development of physically-based erosion models. Copyright (C) 1999 John Wiley & Sons, Ltd.