ABSTRACT
Remote sensing based integrated terrain analysis was carried out for an artificial recharge study in the Ayyar basin area, a typical Precambrian terrain in Tamil Nadu state, India. An analysis of 20 years of water level data has shown that there is a steady decline in water table in this region. The study involves selection of suitable sites for artificial recharge, evaluation of potential site-specific recharge mechanisms and estimation of available surface runoff and aquifer dimension. The site selection process involves generation of different thematic maps from aerial photographs, satellite imagery, geophysical data and a well inventory survey. Rock-soil contact, fold style mapping, lineaments, slope, drainage density, geomorphology, sub-surface geological conditions are some of the parameters analysed in the thematic map integration. In addition to that, statistical analysis was carried out to identify suitable sites for artificial recharge. Once sites were identified, site-specific recharge methods were evaluated on the basis of controlling terrain parameters. Considerations included desiltation of existing tanks, construction of percolation ponds, recharge pitting, recharge wells, subsurface dams and induced recharge. The surface runoff available for recharging the aquifer system was estimated using a computer program, which used satellite derived land use and land cover units among the inputs.
