2-D Flood Modeling of Multiple Simultaneous Dam Failures

Two-dimensional modeling of dam failure flooding has been successfully demonstrated through the use of such models as the CCHE2D-Dambreak model. This modeling approach offers a tremendous improvement over traditional one-dimensional solutions in terms of the high degree of spatial and temporal detail in the model results. Detailed output for water depth, flow velocity, timing of flood arrival and duration of flooding is available from the two-dimensional model such that all aspects of the flood may be thoroughly analyzed. A special case in flood modeling from dam failure involves simulation of the flooding that may result in the event that more than one dam fails and the floodwaters from the multiple dams combine into a single flood event. This may occur when two or more dams are located in tandem along the same river, or it may occur when two or more dams are located on separate tributaries that flow into the same river. Failure of a single dam is a rare event, and multiple simultaneous dam failures are certainly even' rarer. However, the ability to model such an event and understand the potential flood conditions that may occur under various scenarios involving the timing of each dam failure and the water levels in each dam is important. The CCHE2D-Dambreak model offers such a capability, and this paper presents an application of that multiple dam failure modeling feature. An example is presented in which two dams located in tandem on the same river fail, and several scenarios are modeled to investigate the combined flood event.