USING WATER BALANCE TO ASSESS THE GROUNDWATER RECHARGE IN THE AREA BETWEEN RUTBA AND DHABAA, WESTERN OF IRAQ
The study area is located in Al-Rutba city, Al-Anbar Governorate, western Iraq. The metrological data were collected during 1981 – 2016, and used to assess the climatic condition for the study area. The total annual rainfall was 113.3 mm and relative humidity was 47.1%, while the monthly average temperature was 20.1 °C, evaporation was 3074.3 mm, the wind speed was 2.6 m/s with a prevailing direction along the year was NW 29.2%. Data derived from the ratio of wind direction and sunshine duration was 9.2 h/day. The climate of the study area is described as an arid and relatively hot in summer, and cold with low rain in winter. During the 35 years' comparison period, the highest potential evapotranspiration value was 175.82 mm during July and August, while the lowest value was 7.758 mm in January, while the total amount was 970.612 mm. The highest value of the corrected evapotranspiration was 212.74 mm in July and the lowest value was 6.78 mm in January, while the total amount was 1072.021 mm. Water surplus was recorded in the study area was 19.849% of the total rainfall which was equivalent to 113.3 mm. The study area consisted of a thin layer (<0.1 m) of sandy soil, therefore, this thin layer was not considered. A number of key findings are presented which pertain to; the type of rainfall event, wind conditions, and the location. Hence, the value of groundwater recharge was 22.489 mm with a rate of 19.849% which represents the percentage of groundwater recharge from the total rainfall.