NIH/CS/12-13:Groundwater flow modeling in D1 and D2 disributaries of left main canal under Talluru lift scheme of Pushkar canal system

Abstract

Pilot command area of 7393 acres with a geographical area of about 40 sq. km under distributaries D1 and D2 of its Left main canal under Talluru lift Scheme of Pushkar canal system, located in the uplands of the Gandepalli and Jaggampeta mandals in Andhra Pradesh, is studied for its hydrologic budgeting under changed land use conditions. Seasonal groundwater balance has been carried out for study area. Groundwater flow model is conceptualized based on land use, command area and lithology. Modelling is undertaken using MODFLOW to simulate the impact of surfacewater irrigation on the groundwater recharge in the command area. Simulated groundwater level scenarios over different scenarios are analysed. In this study on Pushkar Canal system the interaction of canal water and groundwater is established using stable isotope characterization. The groundwater balance is carried out to estimate the seasonal change in groundwater storages due to rainfall, tube wells and impact of canal network in the study area. Also, a pilot area of D1 and D2 command area and its canal system was setup over an area of 10 by 8 km using MODFLOW. Steady state simulations are done for scenarios of 1980s, 1990s, with canal and with canal and increased pumping (conjunctive use). Results indicate that the aquifer can be used as potential underground reservoir to store surplus flows and to rejuvenate existing wells and to increase their yields. IWRM plans in this direction may be useful in conservation and management of surface water, canal water and groundwater in this upland command area.