Abstract:
For many hydrological studies on an ungaged watershed, a methodology has to be
select for the determination of runoff at its outlet. The Soil Conservation Services
(SCS) curve number method is the most popular method used in estimating the direct
runoff for small catchment. The method can be apply by specifying a single
parameter called the curve number CN, the CN values for a wide variety of soil types
and condition are available in tabulation form. At the same time, the possibility of
rapidly combining data of different types in a Geographical Information System
(GIS) has led to significant increase in its use in hydrological application.
In the present study, SCS method is to be used with GIS to estimate the runoff from
Wadi Su’d watershed, which is located in the Dura area of the Hebron District- West
Bank. 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
estimation of the direct runoff for the study area.
VI
The results of the present study show that the average annual runoff depth for the
study area (Wadi Su'd watershed) is 68mm, and the average volume of runoff from
the same watershed is 127,083.6 cubic meter per year. The amount of runoff
represents 13.6% of the total annual rainfall.
