Technical Abstract: Our ability to predict the rate of breach development and the associated outflow from an overtopped embankment or dam is crucial to characterizing and evaluating the risk due to potential dam failures. Historical databases of dam failures have been used to develop breach parameter prediction equations (i.e., peak breach discharge, breach width, and breach formation time). The small number of well documented historical cases relative to the large number of dams, uncertainties in breach data, and limited information on the properties of the dam embankments has led to large uncertainty in these prediction equations. This uncertainty combined with the perceived risk has historically led engineers, regulators, and owners to take very conservative approaches to prediction of breach parameters for emergency action planning and hazard classification of structures. Today there are several tools available for analyzing dam failures. In addition to the empirical relations developed from the available data, these tools include computational models based on the physical processes. These models continue to evolve and mature as the overall breach process becomes better understood. This paper discusses the physically based breach simulation model SIMBA (Simplified Breach Analysis) that is being developed as a research tool. In this paper SIMBA is used to perform breach simulations representing embankment heights ranging from 5 ft (1.5 m) to 400 ft (120 m) with a range of material properties. The peak discharges predicted by this model are then compared to those predicted by the NRCS peak discharge breach equation. The coherence and reasonableness of the results are discussed along with the impacts of embankment and reservoir properties on these results.