ARS | Publication request: RUN-ON FLOW AND SEDIMENT EFFECTS ON EROSION PROCESSES IN A FLOW CHANNEL

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: October 31, 1999
Publication Date: N/A

Technical Abstract: Erosion processes occurring at a hillslope segment are controlled by water and sediment from its upslope contributing areas as well as surface conditions at the slope segment. In currently used erosion models, the detachment potential of runoff water decreases as the sediment content is increased until a sediment transport capacity, Tc, is reached and excessive amounts of sediment beyond Tc will then be deposited. A multiple boox system was used to evaluate this sediment feedback and Tc relationship in a 0.2m wide flow channel under a range of runo-on and surface conditions. Under seepage conditions, soil was highly erodible and sediment regime became transport dominant. Sediment delivery (S) increased as either run-on water, run-on sediment or soil erodibility was increased. Under drainage conditions, S was significantly enhanced by raindrop impact while such rain effect was less pronounced under seepage conditions. With increasing run-on sediment input, a shift from erosion to deposition was observed at low slopes, rainfall rates and under drainage conditions. This implies that the Tc concept is only applicable to limited conditions and current sediment detachment-transport relationships, expecially for erodible conditions, need to be revised.