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ARS Home » Research » Publications at this Location » Publication #77143
Title: EXPERIMENTAL FLUME STUDY OF HEADCUT MIGRATION

Author
item Hanson, Gregory
item Robinson, Kerry
item Cook, Kevin

Submitted to: Management of Landscapes Disturbed by Channel Incision Stabilization Rehabi
Publication Type: Proceedings
Publication Acceptance Date: 5/23/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: A headcut is a vertical or near vertical drop or discontinuity on the bed of a stream channel, rill, or gully. Headcuts move upstream, which affects the landscape, by contributing significantly to soil erosion. Upstream movement of headcuts also results in structural damage to road crossings, and threatens the integrity of earthen spillways, embankments, and levees that experience flow or overtopping. Understanding headcut movement and th parameters that drive this phenomenon is a complex engineering challenge. This paper describes 1) headcut erosion and the present state of modeling, 2) the large-scale facility designed to examine headcut movement, and 3) the results collected to date. The results from flume tests reported in this paper were analyzed assuming that headcut movement rates could be characterized by linear regression of movement over time. Movement rates determined in this fashion did not have significant correlation to the measured flow parameters but did have significant correlation to the measured soil parameters. Based on an iterative solution, a threshold parameter was determined for each test and compared with those reported in the literature.

Technical Abstract: A headcut is a vertical or near vertical drop or discontinuity on the bed of a stream channel, rill, or gully. Headcut migration affects the landscape, by contributing significantly to soil erosion. Headcut migration also often results in structural damage to road crossings, and threatens the integrity of earthen spillways, embankments, and levees that experience eflow or overtopping. Understanding headcut migration and the parameters that drive this phenomenon is a complex engineering challenge. This paper describes 1) the basic physical concepts of headcut erosion and the present state of modeling, 2) the large-scale facility designed to examine headcut migration, and 3) the results collected to date. Stream power was used as a measure of the energy dissipation at the headcut and is correlated to the migration rate. Basic soil properties such as density, water content, strength, and erodibility were measured and compared with the observed headcut migration rates. At the attack energy experienced in the flume, th measured soil properties have the most significant correlation to the headcut migration rates. The stream power does not show a strong relationship to the migration rate. Based on an iterative solution, migration thresholds were determined for each test. The stream power and threshold values determined for the tests were in the range reported in the literature for headcuts in earthen spillways.