Estimating the Runoff volume of the Sahool Basin, Ibb Governorate, in Yemen Using Remote Sensing (RS) and Geogrphic Information Systems (GIS) Techniques

Abstract

This study was carried out in the Al-Sahool Basin-Ibb Governorate with the aim of estimating the volume of surface runoff in the basin, which is one of the important basins with high rainfall. Its area is )433.5(km2. The importance of this study is to find solutions to the water problem in the basin by knowing the extent of the existing water gap between water withdrawal from groundwater reservoirs, and water recharge from rain through estimating the depth and volume of surface runoff in the basin, based on the USA Soil Conservation Hypothesis(SCS-)CN).which is known as the curve number method for estimating the volume of runoff surface, analyze Land cover data from Sentinel 2 satellite images as well as soil texture data. And determining the hydrological groups. All of these analyzes were done using GIS geographic information system and RS remote sensing techniques. The results of the study showed that the curve number values range between (49-98) with the value (49) representing areas of groundwater recharge, while the value (98) represents areas of surface runoff generation. The results also showed that the depth of annual surface runoff reached (20642.7) mm, and its volume reached (8947.6) during the study period)2000-2020(.