Mumbai is estimated to see its demand for drinking water surge 1.5 times more in the next 17 years and the city needs to prepare for it now. According to civic officials, the daily potable water demand of the metropolitan is estimated to increase from  4,463 million litres currently to 6,900 million litres by 2041. 


The potable water for the city is being sourced from seven lakes currently, however, it is not sufficient as it supplies 3,950 million litres per day (MLD) to the city, as per a Times of India report. 


The seven lakes from the water being drawn include 48% from Bhatsa, 16% from Upper Vaitarna, 12% from Middle Vaitarna, 11% from Modak Sagar, 10% from Tansa, and the remaining from Tulsi and Vihar, situated within Sanjay Gandhi National Park.


The Brihanmumbai Municipal Corporation has planned to bridge the gap by constructing three more dams. Gargai will supply 440 MLD, Pinjal 865 MLD, and Damanganga 1,586 MLD. The civic body has also planned to construct a desalination plant of 200 MLD capacity expandable to 400 MLD at Manori, to augment Mumbai's supply. 


However, tenders repeatedly floated for the desalination plant have yielded no response. A civic official said that the project has only been planned so that the city has some alternative water resources to fall back on in case monsoons fail the city. At present, only the Gargai dam construction plan is at an advanced stage and is awaiting two final clearances, as per the report. 


The demand of 6,900 MLD has been estimated on the basis that Mumbai's population would touch 1,7 crore by 2041, said Purshottam Malawade, chief engineer of the civic body's hydraulics department. The civic body is preparing for the expected increased requirement by working towards transporting water through tunnels apart from new water sources, he said. 


The tunnels would replace the British-era pipelines in many places that have corroded over the years. This would help in preventing water wastage owing to any pipeline burst," he added.


The BMC has also planned to tap additional water by assessing the possibility of constructing a small dam between the Middle Vaitarna and Modak Sagar lakes.