Investigation of Flooding of Downstream Lands under Different Scenarios due to Failure of Ghare Aghach Earth Dam

Simulation of dam failure as well as flood investigation can be used by dam operators. In the present study, the flood zoning due to the piping of Ghare Aghach earth dam in 3 different scenarios that lead to the failure of the dam has been investigated in HEC-RAS software. All parameters due to dam failure were calculated using Froehlich equations. Finally, the flow rate calculated from Froehlich method with the observed flow rate from HEC-RAS software was statistically analyzed. The results showed that the highest peak flow observed due to dam failure in HEC-RAS software is related to the third scenario and is equal to 8935.64 cubic meters per second. However, the lowest peak flow observed due to dam failure in HEC-RAS software is related to the first scenario and is equal to 8231.78 cubic meters per second. Linked results of HEC-RAS software with the Google Earth model show that the highest flooding area occurred in the third scenario and was approximately equal to 22.8 square kilometers and the lowest flooding area is related to the first scenario and approximately equal to 21.8 square kilometers. Correlation due to dam failure using the Froehlich method and the observed peak flow using HEC-RAS software equal to 0.9968 which indicates high accuracy of modeling. Calibration and applaying the linked results of the hydraulic modeles of failure dam as well as HEC-RAS with GIS sofware can be useful in downstream flood zoning for water crisis management.