Computer Simulation of Levee’s Erosion and Overtopping

The overall intent of this research is to develop numerical models of erosion of levees, dams and embankments, validated by physical models. The physical model tests were performed at 1-g and at high g’s using a geotechnical centrifuge facility. The erosion was modeled in detail, from beginning to end, that is from the time the levee was overtopped until the levee was breached. Typical quantities measured as a function of time included the depth, width and volume of rills, number of junction points, rills shape (straight or meandering), sediment transport quantities, and time to breach. This data can be obtained from the numerical modeling, but is difficult to obtain from the physical tests, except at the beginning and end of tests. Video images indicate that the physical modeling results which have been tested in this research agree with the numerical modeling results. Results show that at small water flows, seepage plays a significant role in controlling erosion. Although long-term seepage may eventually cause failure, in the short term low flows tend to reduce erosion by reducing the amount of overtopping.