Controlling breach development during overtopping failure of earthen dams is crucial to minimize loss of human life and property damage. A numerical model to simulate breach development in untreated, and in biopolymer-treated sand dams is presented. The model is based on the solution of two-dimensional depth-averaged mass and momentum flow equations and sediment-mass conservation equation. The model simulates breach widening using a slumping failure module which calculates sediment fluxes when breach side slopes exceed a threshold value. The numerical model is calibrated using results of laboratory experiments for untreated and homogeneously treated dams. The model is then applied to top-layer treated sand dams. Results show that the biopolymer treated top layer slows down breach development, attenuating peak discharge, and increasing the time to peak discharge.
