Applicability of Hydrologic Modeling in Semi-Arid and Arid Region. Case Study: Wadi El-Melaha, Sinai, Egypt

Abstract

In arid and semi-arid regions, the problem of floods indicates the necessity for seeking ways to establish a relationship between the characteristics of basins and the occurrence of floods, by determining the factors influencing the hydrograph of these basins, and then accurately predicting the size and shape of these hydrographs in order to warn of floods; in relation to their time or intensity, or to design protection workings. In addition, rainfall-runoff process is complex and non-linear, so estimating rainfallrunoff is an important process for flood estimation. Moreover, the historical flow records are not available; it becomes necessary to use another tool such as hydrologic models that incorporates watershed characteristics to predict flow rates and the volume of runoff for the watershed. So, the purpose of this study is to investigate the applicability of hydrologic modeling in arid and semi-arid regions to simulate rainfall-runoff through the employing of HEC-HMS model using soil conservation services (SCS) curve number (CN) and SCS unit hydrograph (UH). Wadi El-Melaha was chosen in this study for two reasons: first, Wadi El-Melaha is a sub-basin of Wadi Sudr, which is an experimental catchment established by the Water Resources Research Institute (WRRI) in Sinai as part of an extensive monitoring effort to improve the understanding of the hydrologic processes in Sinai’s arid and semi-arid basins. Second, this Wadi has rainfall and runoff data of two different storms that happened in two different years 1994 and 2011.