Abstract
In Pakistan, water resources are continuously declining due to failure in water governance. The management of scantily utilized hill torrent water resources has become imperative for meeting the grain demand of an increasing population. On an average, 50% of hill torrent water resources are lost due to inefficient conveyance and application practices, and resultantly, the irrigation trend in hill torrent command areas is shifting from spate irrigation to groundwater irrigation. Groundwater provides timely irrigation for potential production but uncontrolled installation of tubewells has created the problems of lowering of watertable and reduction in well yield. About 80% of the farmers of study area have installed tubewells and the installation was increasing at 5% per annum. This paper presents the simulated effects of excessive groundwater pumping in Mithawan spate irrigated area of Dera Ghazi Khan, Pakistan. The data were collected through field visits/observations, farmers' interviews and from relevant organizations. The watertable data were collected from nine observation wells on weekly basis from June 03, 2012 to June 01, 2014. A groundwater hydrological model MODFLOW was used to simulate the effects of groundwater pumping under three different scenarios. The result of Scenario-I indicated an average decline in groundwater level at 2.85m/10years. The result of Scenario-II showed an average decline of 3.64m/10 years. However, the simulated result of model under Scenario-III indicated rise in groundwater head at upstream of command area at 0.01m/simulation period with an average decline of 0.73m/10 years of simulation period. Based on the result, it may be concluded that the use of maximum hill torrent water for spate irrigation would raise groundwater level in the study area.