Estimation of surface runoff volume using the SCS(CN) model in Wadi Zabid Basin – Yemen

Abstract

      Water runoff is one of the most important water resources in arid and semi-arid environments. The amount of surface runoff is important for engineers working in the field of designing irrigation projects and water facilities. Therefore, the study aims to estimate the volume of surface runoff in the Zabid Wadi Basin, in Yemen, with approximately area of (5364.96 km²). Geospatial Analysis was implemented using Geographical Information System (GIS) and Remote Sensing (RS) techniques. Landsat-8 imagery was integrated with digital elevation model (DEM) to perform the analysis. Hydrological characteristics, land use and land cover, climate and soil classification based on the American Soil Conservative Services (SCS-CN), which is one of the most common methods for calculating the volume of surface runoff in rainwater aggregations. The study found that Zabid Wadi basin has hydrological conditions enable to generate water flow during periods of rainfall. This is due to the high value of the (CN) curve of (84). The values of (QV) ranged between (758,700,000-562,926) m³, and the surface runoff volume was (14308647640) m³. This confirms that there is a large amount of runoff water in the study area.