ARS | Publication request: DYNAMICS OF HEAD-CUTS IN UPLAND CONCENTRATED FLOWS

Submitted to: Management of Landscapes Disturbed by Channel Incision Stabilization Rehabi
Publication Type: Proceedings
Publication Acceptance Date: May 1, 1997
Publication Date: N/A

Interpretive Summary: The nature of soil erosion due to head-cut formation is examined in a purpose-built laboratory flume. The soil bed was carefully prepared to replicate field conditions and the soil material was subjected to rainfall followed by an overland flow. A step in the bed surface was artificially formed, and an overland flow produced localized erosion to occur at this step. The growth of this scour, its migration upstream, and all sediment which was transported through the flume were continuously monitored. After a few minutes of migration, a steady- state situation ensued where the rate of advance, the geometry of the scour hole and the amount of sediment eroded remained relatively constant. Although the scour hole became larger with increasing flow discharge, the relative dimensions of the scour hole and its rate of migration did not change appreciably

Technical Abstract: The dynamics of head-cuts in concentrated flows on upland areas were examined in a laboratory channel. Soil packed incrementally into a flume was subjected to simulated rainfall followed by an overland flow. Localized scour was allowed to occur at a pre-formed head-cut, and its upstream migration, morphology, and associated sediment yield were continuously monitored. After an initial period of time, steady-state erosion was observed: the head-cut migrated at a constant rate, the scour hole dimensions did not change appreciably, and sediment yield remained relatively constant. With increasing discharge, the scour hole enlarged but the aspect ratio of the head-cut, the relation between maximum scour depth and downstream deposition, and the rate of head- cutmigration were all conserved