|Robinson, Kerry - USDA-NRCS|
Submitted to: International Hydro-Science & Engineering International Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2004
Publication Date: June 1, 2004
Citation: Hanson, G.J., Robinson, K.M., Cook, K.R., Temple, D.M. 2004. Modeling of erosion from headcut development in channelized flow [abstract]. In: Proceedings of the 6th International Conference on Hydro-Science and -Engineering. Advances in Hydro-Science and -Engineering, May 30 - June 4, 2004, Brisbane, Australia. pp. 289-290. Technical Abstract: A headcut, sometimes called a knickpoint, is a vertical or near-vertical drop or change in elevation of a stream channel, rill, or gully. The drop is a result of concentration of flow energy or stresses over a localized area causing accelerated erosion. Headcuts once formed, migrate upstream due to hydraulic stresses at the overfall, seepage at the base of the headcut, gravitational forces on the earthen mass, weathering processes, and local earthen material properties. Modeling the headcut erosion process has potential applications in several major problems such as geomorphic studies of landscape evolution, stream channel degradation, erosion from agricultural, forest, range, disturbed, and urban lands, local erosion of clay caps protecting hazardous material, earthen spillway erosion, and dam embankment failure due to overtopping. In order to better understand and model headcut development and erosion processes, the United States Department of Agriculture Hydraulic Engineering Research Unit (USDA-HERU) has conducted and continues to conduct several laboratory based experiments to determine the relative importance of various factors including, discharge, tailwater, slope, overfall height, scouring, vegetation, seepage, soil layers, weathering, soil structure, and soil properties. Observations from these tests indicate that the influence of an underlying sand layer can vary from having no impact on headcut migration rate to increasing the rate by an order of magnitude. As a result of these studies, models have been developed and continue to be developed to simulate different aspects of the headcut erosion process including headcut formation, hydraulic stress and pressure, headcut scour, and headcut migration.