Estimation of the Water Balance in the Basin ofWadi Al Hassa

This study addresses the estimation of water balance in the basin of Wadi Al Hassa through the analysis of climatic elements that controls water balance. The study made use of the monthly data of rainfall and temperatures between the period of 1980 to 2015 at the various stations of the study area (Al Hassa, Jurf Ed Darawish, Prince Hassan Nursery (Abur), and Almazar). This study relied on the model of Thornthwaite and Madre (TM) to identify the general water situation in the basin and to determine the areas of water surplus and shortage in the study areas. The study showed that most of the area suffering from water shortage had reach its peak in July and August, where it drained the soil of an aqueous stock water. Aqueous stock water year is divided into: 1) The season of a water surplus that starts from January until March. In this season, the soil takes the moisture they lost during the dry season. 2) The water shortage season starts from April until November. During this season, the amount of the monthly evaporation exceeds the amount of precipitation