As of Tuesday, the total water stock in all seven of Mumbai's water supply lakes stood at 4.1 lakh million litres, representing 28.35% of net capacity. This is higher than last year's 3.65 lakh million litres (25.3% of net capacity) on the same date. In 2024, the figure on April 28 was 2.9 lakh million litres (20% of net capacity).
Government Advisory on Water Usage
A communication issued to all municipal corporations by Maharashtra's water resources department in March cited IMD forecasts indicating the possible impact of El Nino and the Indian Ocean Dipole (IOD), which could result in below-normal rainfall this year. It directed authorities to strictly follow existing guidelines on water usage and reservoir management, with a focus on judicious and economical use of available stocks, prioritising drinking water.
Understanding El Nino and IOD
El Nino is a climate pattern in which the central and eastern Pacific Ocean becomes unusually warm, often weakening the monsoon. The Indian Ocean Dipole is the temperature difference between the western and eastern Indian Ocean; a positive IOD usually strengthens monsoon rainfall over India. Together, these phenomena influence India's weather and monsoon patterns.
Mumbai's Water Sources
Mumbai draws its daily water from the Tansa, Bhatsa, Modak Sagar, Tulsi, Vihar, Upper Vaitarna and Middle Vaitarna lakes. During the monsoon, their catchment areas fill with rainwater, and their overall stock is equated to the actual water stock of Mumbai. The lakes are located on the outskirts of Mumbai and in the Thane and Nashik districts.
The two smallest lakes, Tulsi and Vihar, are located within Sanjay Gandhi National Park (SGNP) and cater to just about 2% of the city's needs. Over 50% of the daily water the city receives comes from just Bhatsa. Though Mumbai has a daily water requirement of 4,200 MLD (million litres per day), the Brihanmumbai Municipal Corporation (BMC) supplies around 3,900 MLD at present.
