SEDIMENT-TRANSPORT COMPETENCE OF RAIN-IMPACTED INTERRILL OVERLAND-FLOW

Laboratory experiments to determine the maximum size of sediment trans ported in shallow, rain-impacted flow were conducted in a recirculatin g flume 4.80m long and 0.50m wide. Rainfall intensities were varied be tween 51 and 138mm h(-1), Bow was introduced from a header tank into t he flume at rates ranging from 0 to 0.64 1 s(-1), and experiments were conducted on gradients between 3.5 and 10 degrees. The following equa tion was developed: ML = (REFE)(1.6363) in which M is particle mass, L is distance moved in unit time (cm min(-1)), RE is rainfall energy (J m(-2) s(-1)) and FE is flow energy (J m(-2) s(-1)). This equation can be used to predict sediment-transport competence of interrill overlan d flow. The equation is limited in its utility insofar as it has been developed using quartz grains and takes no account of variations in ab sorption of rain energy by natural ground surfaces. (C) 1998 John Wile y & Sons, Ltd.