Estimation of flood discharge Design for Sorkheh Hesar river reorganization studies Case Study: Vali town area of Rey city

Abstract

Improvement of river routes influences flood features like flood zone, hydrograph shape, and flow velocity at various stages and to take these measures in the best possible way, it is essential to estimate flood discharge accurately with different return periods. The present study was conducted with the aim of determining the dimensions of the flood design of the Sorkheh Hesar River in the Valiasr town of Shahre Rey (in Tehran). To do this, in addition to the capabilities of Hyfran-plus software, the regional method (by choosing 16 hydrometric stations) besides the methods of flood discharge rate and return period ratio (by selecting Taqiabad station as the base station) were employed. The results revealed a huge difference between the flood discharge rates calculated by different methods that may be attributed to the specific conditions of the studied river basin and taking the advantage of the lowest flood production capacity compared to its surrounding basins. Although the use of flood discharge rate of the base station appears to give more logical results compared to that of the regional method, field studies indicated a more acceptable “return period ratio at base station" than other methods. Accordingly, the peak flood discharge of the river with a return period of 25, 50, and 100 years will be equal to 118, 128, and 137 cubic meters per second (m3/s), respectively. Finally, given the lack of access to the observed hourly floods at the base station, the SCS.