MATHEMATICAL MODEL FOR SIMULATION THE RELATIONSHIP BETWEEN GROUNDWATER AND NORTH AL-JEZIRA IRRIGATION PROJECT, NW IRAQ
Rabia plain is located in the northwestern part of Iraq. It covers an area about 3000 Km2 forming part of the hydrological basin of Wadi Al-Mur which drains from the west to the east and discharges its water to Tigris river near the village of Aski-Mosul. The area is a semi-flat land having an altitude ranges between 325 and 400 m a.s.l. Groundwater in Rabia basin is found in the prevailing sedimentary geological formations in northwest Iraq among which an Injana Formation (upper Miocene) which consists of alternation of clay and sandstone beds covered by recent alluvial deposits. The Northern Al-Jezira is an agricultural project that occupies part of Rabia plain; Tigris River is the main source of surface water which is transported by pumping station, main conveyer canals. The project consists of two stages implemented during two different times; the first one was established in 1992, while the other one was established in 1995. The gathered field data for this study had assisted in applying a mathematical model that aims to evaluate the effects of different irrigation practices on the aquifer. The model has shown that the operation of the project for the next 20 years will lead to increase the aquifer hydraulic head from few centimeters to more than 4.5 m in the modeled area. This increase in hydraulic head is equal to an annual recharge of aquifer storage of about 130 million m3. The results are encouraged a recommendation, aiming to invest the extra recharge gained by the aquifer via digging more wells in the upper layer especially in the second stage area. The extra pumped water could be used to cultivate additional land.