Groundwater potential studies using remote sensing and geographic information system - a research focus

Digital elevation model based extraction of micro watershed helps to demarcate suitable site for groundwater modeling studies using remote sensing and GIS. The present study was explored in over-exploited zones of which out of 15 blocks in Tirunelveli District are under over-exploitation as per Dynamic GW-Resources-2011 while 2009 there was only 4 over-exploited blocks and in 1998 there was no any over exploitation. So, this has to be given more priority for recharge measures as soon as to control this depletion rate. As part of this, the first step is to identify suitable site for artificial recharge. In this paper, the study is undergone for Nambiyar Watershed, hard rock terrain in Tirunelveli District which covers an area of 758.87 km(2). Existence of the scale of groundwater in the study area is determined by four classes ranging from high, moderate, low and poor predicting groundwater potential zones. To derive potential recharge, Landsat 8 satellite data for each month is utilized to estimate evapotranspiration (ET) from the normalized difference vegetation index (NDVI) in the ArcGIS environment. The potential zone map is extracted based on the geomorphology, soil, slope, potential recharge, geology, landuse/landcover, drainage density, aquifer depth, groundwater fluctuation parameters. The weights are assigned to each parameter according to the priority importance to groundwater potential using analytic hierarchy process method. This research identifies site suitable for groundwater recharge and these results are validated and used for groundwater modelling studies.