A Deterministic Headcut Advance Model
Gully erosion is a dominant form of damage to earth spillways. Prediction of the rate of gully headcut movement is desired to assess the risk of a spillway breach. This article presents a headcut advance model composed of a boundary stress prediction model and a mass failure model. Several simplifying assumptions were necessary to predict headcut advance. Model performance was compared with two cases of field damage. The model overpredicted the movement at one site by 44% and underpredicted the movement at another site by 46%. Several topics were identified as needing additional research, and the model provides a framework that can incorporate future research advances.