BENGALURU: With the city and its adjoining areas reeling under acute water shortage every summer, the state govt has decided to enforce a complete ban on cementing of surface areas, especially the setback areas at individual households, to trap rain water and facilitate sufficient recharge of groundwater through topsoil.

Every drop counts

In town-planning parlance, a ‘setback area’ refers to the minimum distance that a building or structure must be built from a property line, street, or a designated area, ensuring sufficient open space.
Commenting on the latest govt initiative, deputy chief minister DK Shivakumar said: “We are hardly recharging the water table because the surface area is completely concrete and there is no space for rainwater to seep in. Hence, we will soon come up with rules to ban concreting of surface areas, particularly the setback areas around houses.”
He added: “People normally put concrete sludge all along the 6-7 feet of setback area, completely covering it with cement, but that cannot be done henceforth in houses that are under construction.”
The deputy CM explained that setback areas will have to be retained with soil surface and plant saplings to facilitate percolation of rainwater.
The issue had cropped up in the legislative council on Friday.
Sources in the town planning wing of Bruhat Bengaluru Mahanagara Palike (BBMP) revealed to STOI that the govt’s move is based on recommendations by experts from the Indian Institute of Science (IISc), who recently studied the groundwater scenario, and reports by the Karnataka Ground Water Authority (KGWA).
‘Bengaluru doesn’t have infra to support water percolation’
Unlike towns in Karnataka, Bengaluru does not have suitable infrastructure to support percolation of water, especially during the rainy months. Constant change in the land usage pattern over the past few decades has left the city’s surface completely covered with concrete, resulting in excess runoff,” explained a BBMP official.
Engineers at KGWA further said that Bengaluru has been on the ‘Red list’ (over-exploited) for the past few years.
“The govt is going all out to ensure recharge of the groundwater table by filling up lakes and digging recharge pits in parks and open areas. But these initiatives contribute little to recharging.” “Rain contributes to groundwater recharge in a bigger way than other methods. Hence, every drop of rain must be allowed to percolate to the groundwater table,” explained a KGWA engineer in the minor irrigation department.
According to a study conducted by KGWA across Karnataka in 2023, while rainfall resulted in the recharge of the groundwater table by 10.3 billion cubic metres, surface water irrigation recharged the table by 4.9 bcm, followed by groundwater irrigation (2.2 bcm), water conservation structures (0.6 bcm), tanks/lakes (0.5 bcm), and open canals (0.3 bcm).