A very slow-acting form of erosion whereby a thin film of water—sheet wash—transports soil particles by rolling them along the ground. Sheet erosion is a major process in the denudation of land surfaces, but R. Morgan (2005) claims that it is only really effective on steep and relatively unvegetated slopes. See Chaplot and Bisonnais (1998) Soil Till. Res. 46 and A. Goudie (2004).