Simulation of Dam-Break Flood Wave and Inundation Mapping: A Case study of Attabad Lake

The break study of Landslide or embankment dams is more essential due to uncertainty in their composition and lack of knowledge of their response to other natural events because they are natural and not properly designed for any disaster. The paper aims to improve different methods of hydraulic modeling of dam break. In this present study dam break of Attabad lake is simulated using the computational fluid dynamics technique. The numerical model (FLOW-3D) is developed to solve the Reynolds averaged Navier-Stoke equation fully in 3D to predict peak flow depth at different cross-sections, peak velocity, peak discharge, time to peak depth, and time to peak discharge. The standard RNGturbulence model is employed to simulate turbulence and then flood inundation maps and velocity vectors for flow at villages are drawn. The results show that most of the flood wave modeled through the Hunza river channel, is contained by the flood plain of Hunza River but for some of the villages i.e. Miaun and chalat, which are situated inside the flood plain of Hunza River are at higher risk of inundation but the flood arrival time estimated for these villages is 31 and 44 min respectively which is enough time for the evacuation of the population to safer areas while for some villages like Hassan Abad situated adjacent to Ali Abad is at higher risk of inundation while the estimated flood arrival time for the village is 12 min which are not enough for the evacuation of the population hence will need some extra flood protection structures for flood containment. The estimate of the peak velocities implies higher shear stress in the river plain, risk of heavy erosion, damage to agricultural lands, residencies, and morphological changes are projected. The analysis of the dam break i.e. Peak depths, Peak Velocities, flood arrival time, and flood inundation maps should only be used as a guide in future risk analysis and flood management.