Incorporating the Effect of Moving Storms into Hillslope Hydrology: Results from a Multiple-Slope Soil Flume

The importance of storm movement on surface flow has long been acknowledged at varying scales ranging from headwater scales to drainage basins. Different studies have shown that moving rainstorms substantially affect surface flow hydrographs, although some of the results reported need further discussion. The main objective of this study is to quantify at the hillslope scale the hydrologic response to both non-moving and moving rainstorms in terms of discharge and soil loss. Controlled laboratory experiments were carried out using a multiple-slope soil flume subjected to a movable sprinkling-type rainfall simulator. To simulate moving rainstorms, the rainfall simulator was moved upstream and downstream over the soil surface at different speeds. Results show that the direction of storm movement, especially for very high intensity rainfall events, significantly affected runoff and water erosion with downstream-moving storms, causing higher peak runoff and erosion than did upstream-moving storms.