ABSTRACT
According to the Palestinian Ministry of Agriculture, the Governorates of the West Bank have been suffering severe drought for the past three years which affected, among other things, the agriculture sector (not enough water for the plants). In summary, water is usually in short supply and the study of surface runoff from small watershed here might help in reducing the effects of such short supply, and this is the interest of this research work.
 
For any hydrological studies on an ungaged watershed, a methodology has to be selected for the determination of runoff at its outlet. Many methods are used to estimate the runoff from a watershed. The curve number method is a versatile and widely used procedure for runoff estimation. This method includes several important properties of the watershed namely, soils permeability, land use and antecedent soil water conditions which are taken into consideration. In the present study, SCS method is used with GIS to estimate the runoff from Wadi Su’d watershed as a case study for agricultural watershed.
 
The Wadi is located in Hebron area of the West Bank, southern Palestine. The watershed having a geographical area of 1.87 square kilometer and the average annual rainfall is around 500 mm. The rainfall and land use data were used along with the experimental data of soil classification and infiltration rate for the assessment of runoff potential for the study area.
 
The results of the present study show that the average annual runoff depth for the study area (Wadi Su'd watershed) is 36.3 mm, and the average volume of runoff from the same watershed is 67840.2 cubic meter per year. The amount of runoff represents 7.3% of the total annual rainfall.  The approach of this study could be applied in other Palestinian watersheds for planning of various conservations measures.