Assessment of Groundwater Potential and Irrigation Water Demand for Sustainable Utilization of Ground water Resource of Mehoni Sub Basin

Abstract

Water balance techniques have been extensively used to make quantitative estimates of water resources and the impact of man’s activities on the hydrologic cycle. In this study, an attempt has been made to describe the methodologies to understand and asses groundwater potential and irrigation water demand of the Mehoni sub basin. The ground water is the main resource of for irrigation and water supply in the study area. Our approach is centered on quantitative estimation of water balance component on the area and developing irrigation areas for sustainable use of the groundwater potential for irrigation. Recharge and discharge components have been quantified based on inflows, outflows and changes in the aquifer groundwater storage. Inflow to the system is groundwater recharge from precipitation by considering the sub basin is closed. The recharge of the study area estimated by water balance technique and each component are calculated separately. The main components for estimation of annual recharge in this paper are annual actual evapotranspiration, surface runoff and rain fall of the study area. The actual evapotranspiration of the study area estimated by Thornthwaite and Mather water balance model and Turc method .The study area is dry basin with no gauged river in the area for which the estimation of surface run off in the basin is done using SCS rain fall runoff method. The irrigation water demand of the study area is estimated by CROPWAT8 software. Discharge from the system includes groundwater extraction for irrigation and water supply systems. Our results show that the average total annual recharge of the area is 72.9 Mm 3 and the total area that can be irrigated by ground water is around 6550ha.