Deciphering Freshwater/Saline Water Interface in and Around Northern Chennai Region, Southern India

Chennai, a city of almost seven million people, is one of the most water-stressed cities of India. While the population keeps skyrocketing, the volume of water available for them is dwindling. Scarcity intensifies conflict between Chennai and its peri-urban areas, which warrants urgent attention. The city receives about 985 million litres a day (mld) against the demand of 1200 mld. The present demand of 1200 mld includes the drinking water requirement for the city and its urban agglomerations that is 950 mld and the industrial demand of 250 mld. This demand is projected to increase to 2100 mld by 2031. Presently, the demand is met from the five freshwater reservoirs besides groundwater is pumped from 6 well fields in the inter-fluve area of the Araniyar and Korattalaiyar rivers. In the last decade, 3 well fields had to be abandoned due to seawater intrusion. In the dry months, seawater intrusion is observed 16 km inland, and after the monsoon, the seawater intrusion moves seaward side and is observed 14 km inland. There is an urgent need to monitor and regulate the fresh groundwater resource of the region. This paper describes the exact hydrological frame walk of the area. Rainwater harvesting and artificial recharge at apt locations in the Korattalaiyar River Plain so that the saline and fresh water interface is pushed further towards the seaward side.