The Calcutta Municipal Corporation will implement rainwater harvesting on a bigger scale to avert a crisis like the one Chennai faces, civic officials said.
Rainwater harvesting — by which rainwater is stored for reuse, such as washing, cleaning and groundwater recharging — is mandatory for buildings in Calcutta with 25,000sq m of roof area or more.
The civic body will implement it, possibly as part of the Jal Dharo Jal Bharo scheme announced by chief minister Mamata Banerjee, in smaller buildings, too, officials said.
“We have decided to introduce the Jol Dharo Jol Bharo scheme in cities,” Hakim, who is also the state urban development minister, said in the Assembly on Wednesday.
“The scheme will be introduced in the Calcutta Municipal Corporation’s jurisdiction, too,” he later said at the civic headquarters.
The Bengal government’s website mentions that the scheme includes “preserving precious water resources by large-scale harvesting of rainwater as well as arresting runoff of surface water”.
Under the scheme, the water bodies whose capacity has reduced are to be re-excavated. It also focuses on groundwater recharging.
Hakim said stored rainwater could be used for washing cars or gardening, for which many use potable water.
“People use potable water to wash clothes and cars at a time when many do not get enough water to drink. If we do not stop wasting water like this, the day when Calcutta will be parched like Chennai is not far away,” the mayor said.
Hakim warned that the groundwater reserve might deplete fast given the rate at which deep tube wells were being installed across the city.
The CMC area has as many as 369 deep tube wells, which supply water to homes that do not get enough surface water. Around 45 deep tube wells were installed in the past year in Jadavpur and Tollygunge.
WATER VOW FOR SALT LAKE See Page 12 Metro has long been highlighting how deep tube wells are being installed as a quickfix solution to the water shortage.
Civic engineers said rainwater harvesting would bring down the dependence on potable water, which in turn would increase the water flow pressure in pipes. “Because of the increased pressure, water will reach those places where it does not reach now. We will be able to serve more people with the water we produce,” a CMC engineer said.
Asis Mazumdar, the director of the School of Water Resource Engineering at Jadavpur University, said: “Rainwater harvesting can be done in two ways — use the stored water to recharge groundwater or use it for gardening, washing and cleaning.”.
Source: The Telegraph