Study on the aquifer response to mountain recharge along the foothills of Courtallam
Abstract
Groundwater is a major source of freshwater for the domestic and agricultural activity. Geologically, the area is characterized by hard rock aquifers made of different rock types like Charnockite and Hornblende Biotite Gneiss. Groundwater in the study area is found to occur in the weathered, fissured and fractured zones in this crystalline rock. The occurrence and movement of groundwater are controlled by various factors like physiography, climate, geology and structural features like lineament and dykes. To understand the grounder water level variation, 3 piezometers were installed in 3 bore wells of selected locations namely Kadayam, Tenkasi and Panpoli. The daily water level data of 8 hours interval has been continuously recorded. This study reflects that a large scale temporal and spatial fluctuation of water level and localized ground water recharge in the crystalline aquifers of the area. As the region is located near the foothills, it is observed that there is immediate recharge after the monsoon during the rain at the mountain block. Daily water level data has been compared with rainfall data to know the water level re-sponse along these hard rock aquifers. The highest rate of rise and variation of water level is seen along the region away from foothills which acts as a storage zone and gets recharged from hilltops. There are also signatures of other water type along the foothills indicating agricultural return flow and recharge of evaporated water sources like tanks and river.
