Technical note: The influence of splashed soil material on sediment transported by rain-impacted flows

Soil material lifted by raindrop impacting flows a few millimetres deep are transported downstream as they fall back to the soil surface. That occurs not only with material that is lifted and remains in the flow, but also material lifted into the air that falls onto the surface of the flow. The amount lifted into the air varies with flow depth and the effect of the input from airborne material on sediment discharged by rain-impacted flows is not normally taken into account in experiments on, or models of, sheet and interrill erosion where flows are more than 1 mm deep. However, in very shallow flows, the airborne input to rain-impacted flows is high and the dominant transport mechanisms the operate in deeper flows no longer operate effectively. Further research into the mechanisms that operate in transporting sediment by rain-impacted flows on slopes with high gradient is warranted.