Flood risk assessment due to dam failure in southern Qazvin province

: Bala Khanlu dam is an embankment dam-clay core which is under construction in southern Qazvin province. The basin (Haji-Arab) of this dam comprises 63000 hectares which is located approximately 35 km southwest of Buein Zahra County. In this paper, the flood risk due to Bala Khanlu dam failure is investigated using an implicit numerical method. For this reason, the depth-averaged 2D shallow water equations in the non-conservative form are solved by the finite difference method (FDM) having a second-order accurate on time and first-order accurate on space. A complete computer software based on the numerical equations has been developed. In case of dam breach in the full reservoir capacity (32 mcm), a shock wave with celerity of about 25 m/sec and height of 20 m can be propagated downstream. This shock can inundate many downstream areas until Sagz-Abad and Amir-Abad, located near Buein Zahra County, just in 20 minutes after the breaching