Technical Abstract: Significant numbers of watershed flood control dams in the United States are approaching the end of their planned service life. As the sediment pools fill and sediment encroaches on the flood storage, the potential for overtopping is increased. Changes in the watershed upstream may also increase overtopping potential, and encroachment on the floodplain downstream may magnify the consequences of a dam failure due to overtopping. These factors have resulted in an increased need for improved mathematical and computer models describing the breach process for embankment dams subjected to overtopping during extreme flood flows. Observation of overtopped embankments in the field and in the outdoor laboratory indicate that it is possible to approach the development of a mathematical model through examination of the component processes. This approach allows simplification of the mathematical description of the complex interaction of the flow with the eroding boundary. Advances in understanding the erosion processes associated with vegetated earth spillways form a point of beginning for component modeling of the breach process. Work has been initiated to obtain the additional data required to expand the spillway erosion concepts for application to development of a physically based embankment breach model. This report discusses the overall breach process and the progress being made toward development of a computational tool for engineering application.