Sadeq Aljawad, Nadhir Al-Ansari
2017 JOURNAL OF ENVIRONMENTAL HYDROLOGY Open Access Online Journal of the International Association for Environmental Hydrology   unpublished
Arid and semi arid regions are characterized by low frequency monthly rainfall events and high evaporation during the remaining dry days. Utilizing monthly rainfall means for water balance calculation risks a high error margin. Even when daily rainfall analysis methods are used to evaluate the resulting runoff in a valley course, errors may still be committed when wrong values are assigned to important field elements such as soil cover type, vegetation and land use. Accordingly and when the
more » ... ly and when the Soil Conservation Service method (SCS) is applied, single storm rainfall and validation of the estimated Curve Number (CN) value using valley flow measurements is necessary. The evaluation of annual runoff volume in a major valley in the Western Iraqi desert using the SCS method applied to single rainfall storm events and validated by actual historical runoff measurements has revealed that Wadi Hauran would exhibit no runoff flow in one year out of three and that runoff may exceed 69 mm depth in a single water year but the average depth for those years with runoff events is only 11.1 mm which amounts to about 64 Mm3 at a location in the center of its catchment area. Journal of Environmental Hydrology