Estimation of Runoff Peak Flow by El-Hames Empirical Method for Ungauged Catchments: A Case Study Iranshahr

Abstract

In this paper, the El-Hames empirical method was used to determine the peak runoff flow in Iranshahr catchment. The El-Hames method is based on morphological parameters and SCS Curve Number of the studied area. The implementing was processed by collecting the required data including soil type and vegetation cover, land use maps, digital elevation model and satellite images from the associated institutions such as Iran Water Resources Management Company (IWRM) and Iran Weather Organization. Then the all data was integrated by using GIS in order to create different layers of required information. The generated layers were applied to determine the morphological parameters through SCS method and to develop the CN map of the study area. Afterward, daily rainfall statistics over the study catchment obtained from synoptic and rain-gauge stations were estimated for 2 to 200 year return periods. Finally, the developed curve number map and the rainfall statistics were imported in the El-Hames formula to estimate the maximum flood peak flow for return periods corresponding to flood events and the hydrographic graphs were plotted. This paper also assessed the validity of El-Hames formula to determine its accuracy. The obtained results of CE and RMSE with value of respectively, 0.97 and 55.95cms prove the accuracy of applied model. Results of this paper can be used as a basis for design and implementation of plans for sustainable development of water resources over the study area and to provide viable strategies for controlling floods and dealing with water crises in this region.