ARS | Publication request: SEDIMENT TRANSPORT CAPACITY AND EROSION PROCESSES

Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: October 18, 1998
Publication Date: N/A

Technical Abstract: Sediment transport capacity, Tc, is the basic concept used to model detachment and deposition processes in current erosion prediction models. Recently, a series of laboratory rainfall simulation studies designed to quantify the effects of surface hydrologic conditions on erosion processes produced data sets making it feasible to evaluate the Tc concept. These laboratory studies used a dual-box system consisting of a 1.8-m long sediment feeder box and a 5-m long test box. Variables used for different surface conditions were slope steepness, hydraulic gradient, and rainfall intensity. Based on relative values of sediment delivery from the feeder and test boxes, five scenarios are proposed ranging from deposition-dominated to transport-dominated sediment regimes. Results showed that at 5 percent slope under seepage or 10% slope under drainage condition, the runoff from the feeder box caused additional sediment transport in the test box, indicating a transport- dominated sediment regime. At 5 percent slope under drainage condition, deposition occurred at low rainfall intensities. Increases in slope, rainfall intensity, and soil erodibility shifted the dominant erosion process from deposition to transport. In addition to flow parameters, Tc was also dependent on soil erodibility that was affected by the near- surface hydraulic gradient.