Investigating the nonlinear response of soil loss to storm direction using a circular soil flume

Although the importance of storm movement on superficial flows has long been recognised, most overland flow and water erosion studies do not take into account the nonlinear effects of the movement of storms across drainage areas on hydrologic responses. The main objective of this study was to investigate in laboratory the influence of the storm direction on overland flow and soil loss from sloping areas. To simulate moving rainstorms, a rainfall simulator was moved along different directions over the soil surface of a circular flume. Runoff and sediment deliveries were measured at the outlet of this flume. The results of the present study show that storm direction, affecting the spatial and temporal distributions of rainfall, has a marked influence on the runoff and soil loss processes. Soil loss resulting from rainstorms moving in different directions across drainage areas are clearly linked with the characteristics of the corresponding overland flow hydrographs, namely, peak discharge. Storms moving downslope are the most potentially hazardous in terms of flow discharge and erosion. (C) 2009 Elsevier B.V. All rights reserved.