Not just on rooftops, but this time deep underground. The Kolkata Municipal Corporation has taken an innovative step to increase the city's groundwater level. A decision has been made to launch underground rainwater harvesting projects in approximately 90 low-lying, waterlogging-prone areas of the city. Among the 144 wards, this project will be implemented in areas where water regularly accumulates during monsoons and pumps have to be operated to drain that water. An official from the Environment Department says, "The time has come for groundwater recharge. If we don't recharge and continue extracting water this way, even the Ganges will dry up within 100 years. Therefore, this initiative by Kolkata Municipal Corporation deserves praise." According to sources from the municipal drainage department, the survey work has been completed.
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This is the first such project in eastern India. According to the plan, monsoon water will be collected in two separate chambers approximately 10 meters underground, filtered, and then returned to the soil. Municipal officials claim this will enable tackling two major problems simultaneously. On the one hand, waterlogging in low-lying areas during monsoons will be reduced to some extent. On the other hand, it will create an opportunity to restore groundwater levels that have been declining in various parts of the city due to long-term dependence on deep tube wells. According to experts, this will also significantly reduce arsenic-related problems.
How will this project be implemented?
According to municipal sources, an open pipe will be placed above ground. Monsoon water will flow down through this pipe to at least 10 meters underground. There, water will collect in a chamber approximately 7 feet long and 4.5 feet wide. The unfiltered water will subsequently be sent to an adjacent micro chamber. After the water is filtered in that chamber, it will again merge with the soil. Areas identified for this project include Ballygunge Phari, Chetla, Kalighat, Judges Court Road, areas adjacent to the Garden Reach Water Production and Supply Centre in South Kolkata, and Bagbazar and Amherst Street in North Kolkata. These locations have been identified after discussions with local councillors, as they know best which areas face greater waterlogging problems.
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According to some municipal officials, if the project succeeds, rainwater harvesting using the same model could be launched in other municipalities across the state in the future. Environmental experts are welcoming this initiative to return monsoon water to nature rather than letting it go to waste. Professor Tarit Roychowdhury of Environmental Science at Jadavpur University says, "Groundwater levels are rapidly declining in districts of South Bengal, including Kolkata. The reason is indiscriminate use of groundwater. That's why arsenic levels in water are also rising. Therefore, if we increase the amount of water underground, the arsenic problem will also be largely resolved."
