GROUNDWATER MODELLING TO QUANTIFY THE EFFECT OF WATER HARVESTING STRUCTURES IN WAGARWADI WATERSHED, PARBHANI DISTRICT, MAHARASHTRA, INDIA

K.P. Gore and M.S. Pendke, Marathwada Agricultural University, Pharbani 431 402, Maharashtra, India
M.S. Pendke

V.V.S. Gurunadha Rao and C.P. Gupta, National Geophysical Research Institute, Hyderabad 500 007, India

Marathwada Agricultural University, Pharbani, has developed about 560 hectares of Wagarwadi watershed in Pharbani district since 1987. Groundwater monitoring on 16 observations wells at weekly intervals commenced in January 1992, and rainfall and pan evaporation has been measured daily at a hydrometereological station situated in the nearby university campus.

Aquifer parameters, namely transmisssivity and specific yeld, have been estimated by carring out a pumping test on a large diameter well. Groundwater recharge resulting from rainfall has been estimated using a water balance model of the soil moisture zone considering soil zone thickness and crops grown. The SCS (Soil Conservation Service) curve number method was used for surface runoff estimation. The groundwater flow model has been constructed using the nested squares finite difference method. Nested square meshes of sizes 160 m x 160 m and 80 m x 80 m have been used and the steady-state condition of aquifer system was simulated in the model assuming the June1992 water level configuration under equilibrium conditions.

The model has been calibrated for transient conditions incorporating additional seepage from the water harvesting structures and their contribution to the groundwater regime has been assessed.