Mumbai: The Brihanmumbai Municipal Corporation (BMC) will kickstart work on widening and rejuvenating two important rivers – Dahisar and Poisar – which originate from Tulsi Lake in the Sanjay Gandhi National Park. These rivers are right now little better than sewers thanks to the industrial effluents, sewage and untreated waste leaching into them from the encroachments along their banks.
Pegged at an estimated cost of Rs1,192 crore for Poisar river and ₹246 crore for Dahisar river, the project includes removal of encroachments, sewage treatment, construction of nallah interceptors to prevent sewage discharge into the rivers and construction of service roads along the banks of both.
Bhagyashree Kapse, deputy municipal commissioner (Zone VII), said that the Poisar river widening would be a major project, involving the razing of 200 slums. “We are trying to rehabilitate eligible slumdwellers or give them monetary compensation to shift,” she said, adding that the rejuvenation would be done by the stormwater drain department but the BMC would help in the removal of structures that came in the way of the river’s alignment.
Kapse added that over 200 slum structures would have to be removed in the Dahisar river project as well. “The rivers now resemble nullahs but we will endeavour to restore them to their original width,” she told HT.
The BMC’s project is based on the recommendations of the Madhav Chitale Committee, which was set up in the wake of the July 2005 deluge that almost drowned the city. One of these recommendations was to widen existing rivers to keep the suburbs flood-free. Incidentally, the committee had remarked that the BMC, in its development plan, had deliberately referred to these rivers as “nullahs” to keep them out of the purview of river laws.
This river rejuvenation project is also a part of the BMC’s Brihanmumbai Storm Water Disposal (Brimstowad) project, launched in 2005 to prevent floods. Under this project, the civic body had planned to augment drainage, construct new drains and widen and de-silt nullahs to increase their capacity.
A civic official from the BMC’s storm water drain (SWD) department said that the sewerage treatment plant (STP) installed for the Poisar river at 10 locations would have the capacity to treat 33.50 MLD of sewerage on a daily basis. The Dahisar river STP, set up at two locations, will have a capacity to treat 6.5 MLD.
The estimated budget of Rs1,192 crore for Poisar and ₹246.62 crore for Dahisar will include operation and maintenance costs for the next 15 years. While the Poisar river rejuvenation will be completed in 36 months, the Dahisar river project will take two years.
The SWD official said that all the disposal outlets like nullahs and stormwater drains connected to the river would be closed and a sewer line would be constructed alongside which, in turn, would be connected to an STP. “This will prevent drain and sewerage water from entering the river. The treated water will be sent back to the river and can be used for secondary purposes. The slush and dirt will also be removed from the river by desilting,” he said.
The project also envisages a 3,153-metre-long service road along the banks of Poisar river and a 1,165-metre-long service road along the Dahisar river as well as roadside drains.
At present, the Dahisar river is 35 to 40 metres wide with a retaining wall already constructed alongside. The rejuvenation project of Dahisar River has been vetted by IIT Bombay.