SIMULATION OF LOWERING GROUNDWATER IN THE RIGHT BANK OF DERBENDIKHAN DAM

This study focuses on the simulation of groundwater flow and investigates the best operation system for the pumping wells of the right bank of Derbendikhan Earth Dam. This dam located at about 50 km south of Sulayamaniyah province, northeast of Iraq. The right bank of the dam suffering from danger of landslides due to high elevations of groundwater and difficulties in lowering the reservoir water level. In order to avoid this sliding problem, this study suggested different scenarios to examine and reduce the groundwater table at the bottom of the sliding zone of the Marl clay layer based on computer software called ground modeling system (GMS) MODFLOW-package to simulate the steady and unsteady states of flow based on three dimensional finite difference techniques. These scenarios are proposed to operate eight wells which are already exist as the first scenario, and the second scenario suggested to drilled two wells in addition to eight wells around the study area. Moreover, the pumping period and reservoir level for all scenarios are ranged between (5-15) days and (450-440) m.a.s.l. respectively. The simulation output found that the second scenario of ten wells, (15) days pumping period and (440) m.a.s.l. reservoir level is the best operation system for groundwater of the aquifer.