K. BALATHANDAYUTHAM, C. MAYILSWAMI AND D. TAMILMANI
Abstract
Groundwater is an important major natural source of freshwater in the world. It is sole source of drinking water in most arid and semi-arid regions. A study was taken up for assessing the groundwater resource parameter in Walayar Watershed of Parambikulam Aliyar Palar (Pap) Basin, Tamil Nadu using Soil and Water Assessment Tool (SWAT). SWAT model runs on the GIS platform and divides the entire watershed into smaller sub-basins based on the digital elevation map of the study area. Each sub-basin is further divided into many homogenous hydrological response units (HRUs) based on the inputs such as soil, slope and land use to represent the natural hydrologic system. The results of the study indicated that 41.31 % of the Walayar Watershed has more than agricultural fallow land, 31.94 % of the land area has Agricultural crops, 14.32 % of the land area has horticultural area and the remaining area is build-up, scrubland, industrial and forest area cover it. The annual groundwater recharge decreases with -11.6, - 22.9, and - 20.6 % for the PRECIS model, and 50.9, 56.7, and 59.0 % increased for the RegCM3 model, for the near, mid and end centuries respectively.