Estimation of natural recharge and its relation with aquifer parameters in and around Tuticorin town, Tamil Nadu, India

摘要

This article describes the estimation of natural recharge and determination of aquifer parameters of a watershed located in coastal belt around Tuticorin town, Tamil Nadu, India, using radioactive tracer and pumping test methods. Recharge measurements were made at several spots to weathered gneiss, shale limestone, quartzite and coastal alluvium formations using tritium injection technique. Static water level was also monitored spatially and temporally. This study indicates that the natural recharge caused by rainfall varies from 15.5 to 107.2 mm with the average value of 61.7 mm, which is equivalent to 10.6% of seasonal rainfall that occurred during the experimental period. The recharge rates were also found to be linearly correlated with the water-table fluctuations at nearby existing wells in the different geological formations. From the recharge data and the change of water level in the exiting wells, the specific yields of shallow phreatic aquifers were estimated for different formations, i.e. 7.25, 9.57 and 10.57% for weathered charnokite, shale limestone and coastal alluvium respectively, which show good consistency with the results obtained from the pumping tests.