Effectiveness of Check Dams in Management and Mitigation of Floods in Quran Gate of Shiraz with semi-Distributed Rainfall-Runoff Simulation

The flood on March 25, 2019 in the Quran Gate of Shiraz led to heavy human and financial losses. Studies of the current condition of the 25 km2 semi-urban watershed of the mentioned area were performed using the SCS semi-distributed rainfall-runoff model. Due to the big difference in average elevation of the Quran Gate watershed with synoptic and rain gauge stations in Shiraz, the precipitation data of these two stations are not suitable for Quran Gate watershed. Therefore, data from satellite models were used. Among more than ten satellite precipitation models, TRMM and PERSIANN were more consistent with field observations of that date. Accordingly, the 24-hour rainfall of the Quran Gate watershed on March 25, 2019 was considered equal to 80 mm. Twenty-two check dams with a height of 5 to 7.5 m were located in the watershed extent and simulated by hydrologic reservoir routing within SCS (NRCS) unit hydrograph semi-distributed model in HEC-HMS. According to the results, the peak discharge and flood volume of Quran Gate decreased from 127.4 m3/s and 1.003 million cubic meters (MCM) to 92.5 m3/s and 0.839 MCM and the time to peak discharge increased by nearly 20 minutes, which shows the positive effects of using check dams in flood control and mitigation.