Submitted to: Current and Emerging Erosion Prediction Technology Symposium
Publication Type: Abstract Only
Publication Acceptance Date: August 7, 1995
Publication Date: N/A
Technical Abstract: WEPP technology is designed to simulate and predict soil erosion principally from raindrops and surface runoff of water. It addresses specifically the processes of soil detachment, sediment transport, and deposition in upland areas. The technology encompasses the broad categories of interrill erosion, rill erosion, and ephemeral gully or concentrated flow erosion. Interrill erosion is characterized by raindrop splash and the transport of sediment in thin sheet flow. Rill erosion is characterized by small channel flow (on the order of 1 cm or less in depth) which moves down hillslopes, and is the principal transport mechanism of sediment over long distances on the hillslope. Ephemeral channel or concentrated flow erosion refers to processes which occur in identifiable channels, which may be stable or unstable, which act as primary transport mechanisms within the watershed routing system. Ephemeral gullies on cropland are typically tilled each year or modified to grassed or otherwise stabilized waterways. WEPP does not address processes associated with classical gullies wherein the principal detachment mechanism is backcutting of the gully walls and subsequent flushing, and which are permanently present on the landscape. WEPP also does not address permanent incised streams and associated stream processes. As such, the size are for which WEPP is applicable will be dependent upon the processes which are occurring on a specific site. The model does include water subsurface lateral flow sub-model which routes shallow subsurface flow to channels, however, the model must be used cautiously in addressing erosion on areas where re-emergent flows are principal erosive mechanisms.