ABSTRACT
ABSTRACT: Environmental isotope techniques have been employed alongwith hydrogeology& hydrogeochemistry for characterizing and identifying factors controlling groundwater quality in Tiruvanmiyur coastal aquifer system. Results indicate that the quality of groundwater is generally fresh except at a few locations. The brackish quality in top aquifer is due to the contribution from the Buckingham Canal and evaporated surface water. Leaching of salts and old seawater are responsible for brackishness & salinity of groundwaters in weathered & fractured aquifer. The saline water is about 7000a BP whereas the brackish groundwater is about 11,500a BP. The two aquifers are interconnected in the western part of the study area but chances of interconnections in the eastern part are remote. The unconfined aquifer is mainly recharged by local precipitation and surface water bodies whereas the semi-confined aquifer receives recharge from the precipitation collected in the depression on the western part of the study area and lateral flow.
