Identifying groundwater recharge zones using remote sensing & GIS techniques in Amaravathi aquifer system, Tamil Nadu, South India

In order to increase the sustainability of the wells and arrest the declining groundwater level trends in Amaravathi aquifer system, southern India, remote sensing and geographic information system (GIS) approach was attempted to identify favourable regions for construction of artificial recharge structures. GIS overlay analysis was carried out wherein 8 layers viz. geology, geomorphology, slope, soil, land use, post monsoon water level, weathering depth and waterbodies/drainage were integrated. Survey of India toposheet, Indian Remote Sensing Satellite IC data and ASTER data were used to develop the various thematic maps. These maps were later transferred to raster data. Groundwater level from the monitoring stations and weathering thickness data from the 248 deep wells constructed were used for the integration. Four zone namely very high, high, moderate and very poor have been demarcated. About 45% of the study area was categorised as high to very highly feasible zone. The existing artificial recharge structures in the region were also plotted and proposed artificial recharge structures were calculated. About 166 masonry check dam, 155 nala bunds, 575 recharge shafts (within tanks), 716 percolation ponds (repair, renovation and restoration) have been calculated and implementation of the proposed structures would create an additional water resource of 198 million m(3) annually.