Runoff modeling using SCS-CN and GIS approach in the Tayiba Valley Basin, Abu Zenima area, South-west Sinai, Egypt

Water is an essential resource that is required in every element of life. Management of water resources necessitates adequate information about the amounts of water supplied from the basins that flows into the sea in particular during the flood seasons. Moreover, because of global climate changes, the hydrologic modeling of the catchments is critically essential for the socioeconomics and life modalities in the study area. So, it's critical to estimate runoff at the watershed level for better understanding of hydrologic processes and locating hotspot areas. Rainfall and runoff are the main hydrologic factors in the evaluation of water resources and they are also the most significant components regulating the basin's groundwater recharge. For this reason, using hydrologic models with trustworthy data is necessary to simulate and estimate water availability with using SCS-CN and GIS approach. In fact, there are a variety of methods available to estimate runoff from rainfall, but the SCS-CN model continues to be the most well known and often used method because runoff curve number (CN) is a fundamental component of the SCS-CN method. In this scope, the purpose of this study is to perform runoff modeling using SCS-CN and GIS approach in the Tayiba Valley Basin. In addition, the SCS-CN model employed inputs of hydrologic soil group (HSG), land use, antecedent moisture condition (AMC), and rainfall value to create CN and compute the CNw and they are necessary inputs to the SCS-CN model for estimating runoff in the Tayiba Valley Basin. Within this context, the use of geographic information system gives us the ability to map and interpret spatial data for factors that affect runoff, such as land use, HSG, digital elevation model, and rainfall. So, results showed the daily rainfall from the Tayiba Valley Basin for nineteen years, i.e., 2001 to 2019. As a result, the annual average surface runoff calculated for the Tayiba Valley Basin is 8.62 mm and the total average volume of runoff is 3080.02 m(2). Finally, these results demonstrate that the hydrologic model will effectively support the Tayiba Valley Basin integrated management through evaluating runoff. In addition, the outcome may also assist many decision-makers in developing and putting into practice effective intervention techniques in the study area.