Running on Empty? Why Mumbai’s Massive Lakes are Choking with Silt, Cutting Water Supply Even When the Reservoirs Look Full
4 min readMumbaiUpdated: Apr 9, 2026 02:16 PM IST
As Mumbai’s maximum temperature continues to soar, a delegation of municipal corporators have demanded a scientific survey of all the seven lakes that supply water to Mumbai to ascertain their water levels. Being a peninsular island city, Mumbai is surrounded by the Arabian sea and creeks from three sides and doesn’t have any natural source of clean water.
Therefore, the maximum city draws its daily water supply from seven different lakes — Vihar, Tulsi, Tansa, Bhatsa, Middle Vaitarna, Upper Vaitarna, and Modak Sagar, of which Tulsi and Vihar are located in suburban Mumbai and the remain five lakes are located in the districts of Nashik, Palghar and Thane. During monsoon every year, the catchment areas of these lakes get filled with rain following which the water is supplied to residents and establishments through water supply tunnels and pipelines.
In a notice of motion filed in the Brihanmumbai Municipal Corporation’s (BMC) civic house by Congress corporator Aysha Vanu stated that due to the large amount of silt accumulation in the lakes supplying water to the limits of the Mumbai the water holding capacity is decreasing. As a result, the problem of water scarcity is becoming more acute during the summer, and the BMC is facing difficulties in supplying water to the citizens.
“In fact, increasing urbanization, deforestation, and uncontrolled garbage disposal are some main reasons for the accumulation of silt in the lakes. Keeping this in mind, the Municipal Corporation is of the firm opinion that all the lakes supplying water to the city of Mumbai should be surveyed scientifically and the silt in the said lakes should be removed in a phased manner and a time-bound program should be chalked out,” read the notice. Furthermore, stating that the civic administration may submit a report on the same.
According to the civic records, the seven lakes haven’t been desilted since 2015. Desilting is a process of removing accumulated granular material mainly sludge comprising clay and mud from the bed of the water body. The accumulation of silt directly affects the holding capacity of any water body along with the overall water quality index.
Civic officials also maintained that reports from Maharashtra Engineering Research Institute (MERI) showed that the silt survey conducted at Tansa and Middle Vaitarna dams reveal that their holding capacity has seen a marginal drop of a mere 0.2 percent.
“Regarding the lake, the organization concerned has reported that the decrease in annual liquid storage capacity is negligible and therefore there is no impact on the water supply capacity,” said an official.
Mumbai has 100 days of water stock left
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The civic record furthermore shows that Mumbai’s overall water stock in the seven lakes stand at 35 per cent or 5.20 lakh litters instead of the total capacity of 14.47 lakh liters. Usually civic officials state that every one percent of stock fulfills up to three days of water supply. However, the officials maintained that owing to the rise in temperature the pace of evaporation is faster.
Last year, the water levels dropped below 20 per cent by the first week of May, however, owing to the early monsoon arrival the catchment areas got replenished earlier than usual.
“This year we are anticipating rainfall to arrive on time, therefore it is unlikely there will be any water cut. However, if the level of temperature continues to increase then the pace of evaporation will increase, leading to faster depletion of water stock,” an official said.
Last year, on April 9 the water stock in the lakes stood at 32.48 per cent, while in 2024, the stock stood at 26.98 per cent.
