The water level of Rabindra Sarobar in south Calcutta’s Dhakuria is dipping again, said regular morning walkers and rowers.
An official of the Kolkata Metropolitan Development Authority, the custodian of the lake, acknowledged that the water level has gone down. "We are monitoring the water level. The situation is not alarming as of now," he said.
Summer is still in its early stages in Calcutta and lake regulars and environmentalists expressed concern that a rain deficit this year would diminish the water level further.
Between March and July last year, Metro carried multiple reports on the depleting water level in the 193-acre Sarobar. The shallow water posed a challenge for rowers and threatened the lake's ecological balance.
Last year, June, July and August had recorded rain deficits. But, September recorded surplus rain.
This year, the start of summer has already seen two heat waves — the second is still ongoing — in south Bengal. The Met office has ruled out uniform showers in Calcutta any time soon.
On Monday, a pile of slush was visible along the banks of the Sarobar. The depth of the water along the banks is usually around more than five feet, regular rowers said. But on Monday, multiple spots at the banks barely had any water. The surface was mostly slush.
The embankments of the water body also pointed to the sliding depth of the water. The concrete walls are at least a shade or two darker — with a tinge of green that comes from the algae — downwards from the middle. It suggests the usual level of the water. On Monday, the water was much lower than the centre.
The depth of the water along the banks is usually around six feet. But now at most places, it is barely three feet, said sources.
At multiple spots, there is no water at all and the surface is just slush, said a veteran rower.
Two concrete base slabs that support the hanging bridge also showed the depleting water level. Dark patches in the middle of the slabs suggested the usual water level. The current level was almost at the foot of the slabs, more than two feet below the normal level.
A couple of valves are in place to drain out excess water from the lake. But the water level is lower than the valves at the moment.
"I have been visiting the lake for morning walks every day for the past seven to eight years. I have not seen the water level sliding as much as I did last year. It is alarming this year as well," said Debraj Bose, a restaurateur who lives near Lake Gardens.
The Sarobar was once connected to the Adi Ganga (Tolly Nullah) by a pipeline that passed beneath the Tollygunge railway bridge. The link was snapped because of the construction of the Metro Railway line. Since then, the water level in the Sarobar has been dependent on seasonal rain, said old-timers.
"The water level has dipped. It has not yet posed a challenge for rowing. But the summer has just started. No one knows what will happen after a month if the city continues to be hot and dry," said Sudip Naha, captain of the boats at Lake Club.
On Monday, the Met office recorded a maximum temperature of 39 degrees in Alipore. The mercury dropped below 40 degrees for the first time since Thursday. But "heat-wave conditions" are expected to make a comeback from Wednesday, according to a Met bulletin.
Last year, the depleting water level in the Sarobar posed a challenge for rowers. The Sarobar is the only natural venue for the sport in Bengal.
The fins (metallic structures fitted under the hull) of rowing boats got stuck in the slush when the oars drifted towards the bank. The oars, too, got stuck, causing damage to the boats.
Punarbasu Chaudhuri, associate professor in the department of environmental sciences at Calcutta University, attributed the dip in water level to the hot and dry weather and unregulated use of groundwater by apartments.
"The rise in solar insulation is leading to more evaporation. But water in the Sarobar is connected to sub-surface aquifers. Many multi-storeyed apartments use submersible pumps to extract water from the aquifers this time of the year. This leads to a dip in the groundwater level which in turn affects water bodies like the Sarobar," said Chaudhuri.
