Skip to main content
ARS Home » Research » Publications at this Location » Publication #63433
Title: EVALUATION OF THE DETACHMENT-TRANSPORT COUPLING CONCEPT IN THE WEPP RILL EROSION EQUATION

Author
item HUANG, CHI-HUA - PURDUE UNIVERSITY
item Bradford, Joe
item Laflen, John

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Erosion models commonly treat sediment detachment and transport as coupled processes. This research refuted the coupling concept and found that by separating the sediment detachment and transport components, the spatial separation between rill and interrill areas can be alleviated.

Technical Abstract: The rill erosion equation in the current Water Erosion Prediction Project (WEPP) model is based on the coupled detachment and transport processes concept proposed by Foster and Meyer in 1972. The first order detachment-transport coupling states that the rill detachment rate is proportional to the difference between transport capacity and sediment load. A field experiment was designed to examine the validity of this model. Flow channels, 0.2-m wide, with clear water introduced at the up-slope end were used in the study. Sediment delivery from different channel lengths and inflow rates was measured. Data were collected for three soils: Russell silt loam, Saybrook silt loam, and Sharpsburg silty clay. Results showed that rill detachment and transport are not coupled processes. In the upper reach of a channel, sediment load is limited by a soil-dependent detachment rate. For longer channels, transport capacity controls the sediment delivery. Experimental data supported the Meyer and Wischmeier (1969) model, in which detachment and transport processes are separated and sediment delivery is limited to the lesser of the two. A slight modification to the Meyer and Wischmeier model is the inclusion of an 'overshoot' situation (i.e., sediment load is greater than transport capacity) when the sediment regime is shifted from a detachment-dominated to a transport-dominated condition. Additional work is required to expand the database to develop a validated rill detachment and transport model.