While an RTI (Right to Information) query filed by the NatConnect Foundation recently found that none of the seven lakes catering to Mumbai's water demands have been desilted in the past 10 years, the Brihanmumbai Municipal Corporation (BMC) said that reports from Maharashtra Engineering Research Institute (MERI) showed that the silt survey conducted at Tansa and Middle Vaitarna dams reveal that the their holding capacity has seen a marginal drop of a mere 0.2 percent. The civic body said that the MERI institute is also slated to submit a report on sedimentation in Vehar and Tulsi lakes. Amid a RTI response indicating that no desilting had been carried out in the past ten years, environmentalists had flagged that silt accumulation in reservoirs impacts water capacities and leads to inaccurate data. On Friday, BMC said that a silt survey conducted by MERI at Tansa and Middle Vaitarna lakes show that while the annual storage capacity of Middle Vaitarna has decreased by only 0.244 per cent, the capacity of Tansa has only reduced by 0.116 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 a civic statement. The BMC said that the Nashik-based institute has also conducted surveys at Vehar, Tulsi and Modak Sagar lakes with the reports on the survey yet to be furnished. Meanwhile, BMC maintained that the water supplied to Mumbai through the seven lakes is 99.34 percent pure, as per Jal Jeevan Mission programme.
