Abstract
Dam break modeling is the process to analyze the risks of flooding downstream of a dam by simulating the possible dam failure scenarios. The risk of flooding has always been a very crucial issue in flood control projects. Dam breach analyses are used to estimate the potential risks associated with the failure of a dam. This paper focuses on the estimation of the maximum discharge downstream of the Dam in case of dam failure and further propagation of dam break flooding. As case study, Attabad Lake Dam created because of land sliding in Hunza valley has been considered, which is located about 100 km upstream of the confluence of Hunza and Gilgit Rivers. The project reach is about 100 km downstream of the Attabad Lake. The project reach has been modeled with unsteady flow conditions by using the one dimensional model HEC-RAS. Different scenarios of dam overtopping failure were simulated in HEC-RAS and the results were thoroughly analyzed. The maximum discharge downstream of the dam in the worst case scenario is 90534 m3/s. This study is intended to provide useful guidelines for the realistic estimation of flood severity in a river valley due to possible dam failure.
Keyword(s)
Attabad Lake, Hunza River, Dam break Analysis, Overtopping Failure, HEC-RAS