The mechanics of raindrop splash erosion of soil were investigated by using waterdrops impacting at terminal velocity onto various depths of water over smooth glass. Splash weight produced by waterdrop impact varied with waterdrop diameter D and surface water depth d. For a smooth hard surface, predicted splash in terms of waterdrop weight was zero at d/D = 0 and increased to a maximum at d/D of 0.14 and 0.20 for D = 0.559 cm and 0.296 cm, respectively. The influence of greater depth became relatively insignificant at a depth of about three drop diameters.