Estimation of water balance for the central basin of Erbil plain (North of Iraq)

Erbil city located, in the northern part of Iraq, within the central basin of Erbil plain which covers an area about 1400 Km2 where Erbil city area measures about 70 Km2, is located between latitudes (36ᵒ 08 30̋ - 36ᵒ 14 15̋) north and longitudes (43 ° 57 '30 "- 44 ° 03' 20") east, The rocks exposures at the central Erbil plain date back to the (Upper Miocene-Recent) and this includes Ingana, Muqdadiya, Bai Hassan formations as well as Quaternary deposits. Tectonically, the studied area is located within Chumchamal-Butma Subzone at the area of the foothills. The movement of the groundwater in the study area is from the east to the west. Depending on the climatic data recorded in Erbil station for the period (1980-2016) shows that the total falling rain was (418.0) mm, and the temperature (15.81 ° C), relative humidity (29.96%), wind speed (1.94 m / s), solar brightness (8.28 hours / day) and the total evaporation from free surfaces was (1674.8 mm) the prevailing climate in the region is moist-humid to moist. corrected potential evapotranspiration was calculated theoretically apply Thornthwaite method where she was value 734.58 mm, was also calculate the water surplus , which accounted for 79.18% divided into surface runoff and its value 39.36 mm and Groundwater Recharge 87.82 while the water deficit represents 20.82% of the annual rainfall as the annual recharge rate was calculated for Erbil Central Basin and is reached 122.94 × 106 m3/year.