The Kolkata Municipal Corporation (KMC) is struggling to lift water from the Hooghly during low tide because of a drop in the water level, resulting in a fall in the daily potable water production.
A drop in the water table of underground aquifers is also hitting the supply in pockets dependent on groundwater as pumps are not being able to lift an adequate volume of groundwater, officials said.
Large parts of southeast Calcutta like Jadavpur, Purba Jadavpur, Kasba, Garia, Tollygunge and the Tiljala-Topsia belt are among the places that depend fully or partly on groundwater lifted by pumps.
The double blow prompted mayor Firhad Hakim to issue an appeal to Calcuttans to be economical with their water consumption and stop wasting water.
KMC officials said the water level in the Hooghly has gone down to such an extent that the mouth of the suction pipes are above water or barely under water for some time during low tide.
This is forcing the KMC to shut down pumps for certain durations. The volume of the water being lifted is declining.
The raw water drawn from the Hooghly is sent to the water treatment plants. The treated (potable) water is then supplied across the city.
“Water production has declined because the level of water in the Hooghly has dropped. The stations that lift raw water are facing problems because of this. We are trying our best to supply an adequate volume of water but people should not waste water,” Hakim said on Monday. “People should restrict non-essential activities like car washing.”
Calcutta is in the grip of extreme heat and high temperatures. There has been no rain for more than 20 days.
There are five water lifting stations of the KMC along the Hooghly — at Takta Ghat in Kidderpore, Mullick Ghat near the Howrah bridge, Ma-er Ghat in Bagbazar, Palta and Garden Reach.
“All the stations are facing the same problem. We are trying to compensate by producing more water during high tide but we cannot compensate entirely for the loss,” said a senior official in the KMC’s water supply department.
The drop in production and the increase in demand because of the heat has led to a spurt in the demand for water tankers, which are sent to water-scarce localities.
“Our water tankers are doing about 1,300 trips a day. This is nearly 25 per cent more than the trips they make during winter,” said the senior official.
Aditi Mukherjee, a scientist and an author of the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), published last year, said the extreme climate events and climate change will make water a more scarce resource.
“One of the factors for the drop in surface water and groundwater availability will be the absence of rainfall and the change in rainfall pattern,” said Mukherjee, the lead author of the chapter on water.
“The dip in groundwater is also because of human activities, which have reduced the scope of groundwater recharge by destroying water bodies and paving more areas.”
This is true for most cities across the globe and nearly 70 per cent of the cities source their water from underground, she said. Most of Calcutta’s water needs are, however, met by the Hooghly.
