The Brihanmumbai Municipal Corporation (BMC) has responded to recent concerns about silt accumulation in Mumbai’s lakes by asserting that despite a decade of no desilting, the impact on water storage capacity remains minimal. This clarification comes in the wake of a Right to Information (RTI) response which revealed that none of the seven lakes crucial to Mumbai’s water supply have undergone desilting operations over the past ten years.
Environmentalists have expressed concerns that the accumulation of silt in these reservoirs might affect their storage capacities and lead to inaccurate water data. However, the BMC has countered these concerns with findings from the Maharashtra Engineering Research Institute (MERI), which conducted surveys on the Tansa and Middle Vaitarna dams. According to the BMC, these surveys indicate only a marginal reduction in holding capacity—0.2 percent—at these sites.
Specifically, the report from MERI highlights that the annual storage capacity of Middle Vaitarna has decreased by approximately 0.244 percent, while Tansa’s capacity has seen a reduction of about 0.116 percent. The BMC emphasised that these decreases are so negligible that they have no substantial impact on the overall water supply. In addition to the Tansa and Middle Vaitarna dams, MERI has also conducted sedimentation surveys at Vehar, Tulsi, and Modak Sagar lakes, though the results for these reservoirs are still pending. The BMC has indicated that they are awaiting these additional reports to further clarify the state of these lakes.
The civic body also assured that the water supplied to Mumbai from these lakes remains of high quality, with a purity level of 99.34 percent, as per the Jal Jeevan Mission standards. This statistic underscores the BMC’s commitment to maintaining water quality despite the silt accumulation issues. While the RTI findings have sparked concerns regarding the state of Mumbai’s reservoirs, the BMC’s latest statements aim to reassure the public that the impact on water storage and quality is minimal, based on the most recent silt survey data.
