Study on the effect of groundwater recharge through water harvesting structures in semi-arid red soil region of south India

Abstract

A study was conducted to investigate the effect of Water Harvesting Structures (WHS) on groundwater (GW) recharge during 2004-08 in red soil watershed of semi arid region, namely K.D. Pally watershed (920 ha) in Kambadur Mandal of Anantapur district, Andhra Pradesh. Four WHS namely, P. Reddy Check Dam (PRCD), G. Reddy Percolation Tank (GRPT), Small Check Dam (Small CD) and Village Percolation Tank (VPT) of storage capacity 1.67, 4.36, 0.33 and 3.93 ha- m, respectively having a total capacity of 9.4 ha-m. One time filling were selected to assess their effect on GW recharge. In the present study, structure wise simple linear and multiple regression equations with API as an additional factor were developed to predict the runoff expected in a particular rainfall storm, for all four structures. The hydrological analysis showed that curve number (CN) was found to be less and storage (St) was higher in case of computed values from observed data using methodology prescribed in the present study compared to Hydrologic Soil Cover Complex method. Potential recharge has been estimated and empirical relationships were developed between cumulative potential recharge and cumulative rainfall. Changes in ground water utilization pattern was also studied and found that the irrigated area expanded up to 113.5 ha in post-project as against 37.2 ha pre-project. The present study showed that the WHS had very good impact on ground water recharge in the study area. Therefore, it is recommended that the study can be applied for similar other region for approximate quantification of surface storage and ground water recharge.