Skip to main content
ARS Home » Research » Publications at this Location » Publication #103965
Title: PREDICTION OF HEADCUT MIGRATION USING A DETERMINISTIC APPROACH

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

Submitted to: American Society of Agri Engineers Special Meetings and Conferences Papers
Publication Type: Popular Publication
Publication Acceptance Date: 7/22/1999
Publication Date: N/A
Citation: Hanson, G.J., Robinson, K.M., Cook, K.R. 1999. Prediction of headcut migration using a deterministic approach. American Society of Agricultual Engineers. Paper #992160. 12 p.

Interpretive Summary: The upstream movement of headcuts, vertical or near vertical drops in elevation, is an important part of the erosion process for stream channels, earth spillways and embankments, and other landscape features. Upstream movement of headcuts causes loss of productive land, damage to bridges, and risk to people living downstream of flood control structures. Predicting the rate of upstream movement of these headcuts is important, but difficul because of the complexity of the process involved. To assist in improving the relations used for prediction, headcut movement was studied experimentally at a large scale in the controlled environment of an outdoor hydraulics laboratory. Physically based mathematical relations were developed to describe the headcut movement observed. When applied with appropriate judgment, these relations may be used by engineers and geologists to estimate headcut movement and the associated extent of erosion.

Technical Abstract: A headcut is a vertical or near-vertical drop or change in elevation of a stream channel, rill, or gully occurring where there is concentrated flow. Headcuts migrate upstream due to hydraulic stresses at the overfall, basal sapping, weathering processes, as well as gravitational forces on the soil mass. The rate of headcut migration is of specific interest for river restoration, landscape management, earthen spillway, and embankment design Headcut migration results in loss of productive land, and damage to the infrastructure such as bridges, spillways, and embankments, causing not only economic problems but safety issues as well. Predicting the rate of headcut migration is a complex problem. Headcut migration results from 50 tests conducted in a 1.8-m wide and 29-m long flume with 2.4-m high sidewalls are compared with predicted migration rates using a deterministic computer model and a simplified deterministic equation. The material parameters required by other physically based models are at best empirically related to soil properties such as material strength, percent clay, and water content. The approach utilized in this paper is an improvement in that it uses soil properties directly in the physical development. The cu value from the unconfined compressive strength test and erodibility values from the submerged jet test were used in the analysis of the flume test results. Predicted migration rates agree with measured data.