Mumbai: The three professors from the Indian Institute of Technology Bombay (IIT - B) in their report have recommended constructing a new tank for emptying the existing tank for repairs or reconstruction of the Malabar Hill Reservoir (MHR). However, the report filed by the four members of the expert committee earlier has been contradictory to this report. So to take a final call on these two different reports, the civic authorities will be consulting a water expert.
Public Outcry Leads To Appointing Expert Committee for Reservoir Decision
After heavy uproar from the citizens and the activists, the civic authorities on November 3, 2023, appointed an eight-member expert committee to decide whether the British-era reservoir should be reconstructed or just repairs would suffice. The four members (local representatives) on the committee who submitted the interim report on January 8, said that the reservoir is in good structural condition and does not require demolition or reconstruction for the next 10–15 years as there is no danger of collapse disrupting the water supply. Hence, the BMC stressed that the final report, including the advice of the professors from the IIT-B, as conclusive recommendations.
IIT Professors' Submit Their Final Report With Recommendations
Accordingly, the three IIT professors submitted their final report on February 29. The report stated that, "The visual inspection of the tanks indicated structural damage along with non-structural damage, implying that this damage should be repaired at the earliest convenience. To carry out the above repairs effectively, the tanks need to be in empty condition. An alternative arrangement should be in place before emptying the service reservoirs, which ensures an uninterrupted water supply. However, phase-wise repair or reconstruction of the tanks of the MHR is not possible without affecting the water supply until a new tank/reservoir of the requisite capacity is constructed."
Recommendations For Additional Tank Construction
The report suggests construction of additional tanks with a capacity of 52.44 million litres that will ensure undisturbed water supply during the repair of MHR, close during periodic maintenance, and meet the deficit in water supply. After taking a review of 145 suggestions and objections, the experts have suggested planning the new facility in such a way that it will affect a minimum number of trees. The report further stated that "The Mumbai water supply scheme is one of the best planned, designed, executed, and operated systems in the category of gravity flow water supply systems, having served for more than 100 years. The BMC should be proud and prepare a master plan to maintain this as per the standards and as a functional heritage water supply system."
BMC Struggles With Conflicting Reports
Meanwhile, the BMC has not been able to take a final decision due to two different reports from the expert committee. So an expert from the water field will be appointed to take a final call, said a senior civic official. The 135-year-old reservoir beneath the Hanging Garden supplies 147 million litres of water per day to south Mumbai. Its reconstruction and augmentation proposal was approved in February 2022 at an estimated cost of Rs698 crore. Locals were up in arms against the project as it required axing of 189 fully grown trees.
Eight Member Expert Committee
The total eight members committee, included IIT Professors, Alok Goyal, RS Jangid, Jothi Prakash and Dasaka Murthy, Deputy Municipal Commissioner (DMC) special engineering, CH Kandalkar and three independent members along with architect Rahul Kadri, structural and civil engineers, Alpa Sheth and Vasudeo Nori. The report stated that the independent members (Kadri, Sheth and Nori) didn’t consent to signing of the report.
Measures recommended by experts
* As an immediate short-term measure, the cleaning of the tanks as per the CPHEEO (2005) manual shall be taken up on a priority basis. This includes desilting, the removal of roots inside the tank walls and the roots of large garden plants on the top, and the removal of rust from pipes and structural steel staircases.
* The new alternative tank should preferably be constructed on the land reserved for the hydraulic facility, and being on the hill site, the BMC shall carry out a proper geological investigation, and the design of the tank shall be accordingly carried out with proper safety measures.
* A scientific structural and hydraulic audit of the 100-year-old existing tanks should be carried out. Also, a rigorous visual inspection of the tanks should be carried out to assess structural damage.
* Non-destructive testing of the structural elements of the tanks and destructive testing of the materials of tanks shall be carried out.
* Load tests on the roof of the tanks shall be performed to assess the present load-carrying capacity as well as the inherent elasticity.
* The seismic safety of the existing tanks to current codal requirements shall be assessed.
* Based on the outcome of the above, a decision to either repair or reconstruct the existing tanks of MHR shall be taken up.
