Stable Isotopic Characterization In Surface And Groundwater Interaction In A Hard Rock Terrain Of A Semi-Arid Region

The Deuterium (δD) and Oxygen-18 (δ18O) isotopes can be used to understand the surface and groundwater interaction and identifying the recharge sources. Pelig.K.B [5] identified that origin, age, distribution of waters in a region including occurrence and recharge mechanism, interconnections between groundwater bodies and identification of recharge sources and areas can be easily identified by environmental isotopic techniques. The study area has 16 tanks and 72 wells. Variation in stable isotopic signature of groundwater in Sindapalli sub-basin was used to understand the process of surface and groundwater interaction and recharge process in hard rock aquifer. The present paper describes the groundwater condition in the sub-basin and gives a detailed account of the isotopic signature in precipitation, tank water and well water. The pre and post monsoon water samples of each tank and wells are taken for isotopic analyses for identifying the recharge sources of groundwater level within the sub-basin. The samples were analyzed fort isotopic data and it is presented in terms of the Global Meteoric Line (GML) and its variation with Local Meteoric Precipitation Line (LML) with respect to tank and groundwater line as δD vs δ18O plots for 2009 and 2010. The results indicated that the δ18O and δD values of groundwater are changing from pre and post monsoon with respect to aquifer depth and indicate the presence of recharge due to rainfall. It is noted that interaction of surface water with hard rock?s might cause δ18O to be high. The spatial variation of δ18O values in the study area can be used in identifying suitable locations for undertaking artificial recharge measures in the aquifer to supplement the natural recharge of groundwater.