Conjunctive Use Modeling of Surface Water and Groundwater in The Jolak Basin , North Iraq


This study contributes to the understanding of the conjunctive use of surface water and groundwater models of the Jolak basin (in the northern part of Kirkuk city, north Iraq) ,with an area of 400 square-kilometers .The first stage of this work was to collect a dataset to characterize the surface and groundwater .Soil and Water Assessment Tool (SWAT) and the Groundwater Modeling System(GMS) were adjusted in an interactive manner. In SWAT, a basin to be modeled is divided into multiple sub basins that consist of a homogeneous land use, ground slope, and soil characteristics. Land use map which was developed by Digital elevation model (DEM), that describes the elevation of any point in a given area at a specific spatial resolution, identifies the deferent classifications of land use. Soil Conservation Service (SCS) curve number method was chosen to estimate the surface runoff. The produced runoff volume was suggested to be stored in the several ponds and conveyed to the underground reservoir in order to use it with conjunction of ground water during drought seasons. SWAT modeling of the groundwater is extremely simplified, so the Groundwater Model System(GMS) was employed to specifically describe the groundwater processes. This model interpreted the available groundwater levels, which is not possible with the used of SWAT. The study suggested using several wells (which already exist in the study area) to be operate at a constant rate in order to divert the stored surface water in to groundwater. The annual average runoff overall the basin is estimated to be about 1.5×108 m3. This value is suggested to be conveyed to ground water through exiting pumping wells. The results showed that the ground water levels in basin can be raised with about 2m at the middle of the study area from its present level after the steady state condition is reached.