摘要
Estimation of runoff volume in Wadis of intermittent flow is very important in order to manage the scarce water resources and mobilize Wadi flows efficiently. In Yemen, the availability of accurate runoff information is rare, which poses a serious challenge for hydrologists. This study used the soil conservation services curve number (SCS-CN) method with conventional database and the geographical information system to estimate the runoff volume of Wadi Zaher, Harad and Al Ghayel. The Wadi is located in the southwest of Sana’a City, the capital of Yemen. The area of the Wadi is 350.24?km2, and the average annual rainfall is 284?mm. The study area is classified into four hydrological soil groups. The average curve number for normal condition is 77.6, where the averages of the dry and wet conditions are 59.5 and 88.8, respectively. The results, obtained by the SCS-CN method, show that the average annual runoff depth for Wadi Zaher Al Ghayel watershed is 212?mm, and the total runoff volume is estimated to be 75.80?mm3, which is 76?% of the total annual rainfall. This approach can be applied in other Wadis in Yemen for the purpose of planning and development.