Water woes | Drought hits Sankey Tank in Bengaluru, most parts of the lake dry 

Sankey Tank, one of the well-maintained lakes in the city and a landmark in north Bengaluru, has been hit by the drought. Most of the lake is dry now and even where there is water, it is mostly only a few feet deep. 

“Either I or my students have been studying Sankey Tank at least from 1996. The water level has never gone down so low as today. It is sad to see the lake like this,” said T. V. Ramachandra of the Centre for Ecological Sciences, Indian Institute of Science.

Created in 1882 by Col. Richard Hieram Sankey of the Madras Sappers Regiment, Sankey Tank is a rainfed lake. The IISc. is a prominent part of its catchment area, apart from Sadashivanagar and surrounding areas.

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“The lack of rain in the city, and particularly in these parts of the city, has dried up the lake. Moreover, due to rising mercury, the rate of evaporation of water from the lake is also high,” said Prof. Ramachandra.

Water conservationist S. Vishwanath said the water loss due to evaporation was around 1.8 m per year, which translates to around 7 mm per day. If we assume the next big rains are 40 days away, we will likely lose at least 28 cm of water level more just to evaporation by then.

Sankey Tank is groundwater-fed, and surface-water-fed during the rains.

“The catchment area of the lake has been paved for most parts. There is over-exploitation of groundwater through borewells, which also depletes the water level,” said Prof. Ramachandra. He added that unlike before there was sewage coming into the lake and the present water level in the lake was also due to this. 

The lake drying up has left walkers and those working to protect the water body worried.

“Ironically, Sankey Tank was built in response to the drought of 1874, as a drinking water source for locals. Now, decision-making on civil work at Sankey Tank is undertaken without the vital inputs of any ecological experts. So, there is no one keeping in mind best practices for lakes, and the wetland laws. As a result, we now have an overly concretised lake resulting in an impermeable layer, diminishing the scope for water to percolate. Additionally, when temperatures rise as they have been recently, the concrete magnifies the heat and essentially creates an urban heat island,” said Preeti Sunderajan of Citizens for Sankey.

The condition of the lake has also affected the bird population in the surroundings.

“A lakebed and its surrounding areas need trees, shrubs and bamboo to attract birds and maintain the catchment area. In Sankey, apart from a few trees, we have ornamental plants and palm trees. We urgently need wetland experts who are looking through the lens of conservation and preservation to direct what development can or cannot happen around a lake. The lakes in Mysuru, especially the Kukkarahalli Kere, are a good example of how a lake in a city can be preserved,” Ms. Sunderajan said.

“The lake drying up has affected the bird population as well. There were 45 species of migratory birds at the lake. Now, most of them have not been seen for several months. However, we haven’t done a survey recently. We need to plant trees that attract these birds around the lake, but we have planted palm trees, which are not a native species and do not even give shade. We have also concertised the walking path around the lake, and its width is more than the Sankey Road that they wanted to widen. Walk paths around the lakes should not be concretised, but maintained like at Kukkarahalli Kere in Mysuru,” said Ms. Sunderajan. 

“We, as walkers, also treat the lake like a picnic spot, but do not allow the lake to breathe. All the work carried out around the lake for our comfort has choked the lake. Development around the lake has also increased,” lamented Balakrishna V., a regular morning walker at Sankey Tank.