- The new Bill in Karnataka proposes changing the standard 30-metre buffer zone around all water bodies, to incremental buffer zones based on the size of the water body.
- The Bill is being strongly criticised by Bengaluru’s citizen collectives and environmentalists, who say that any construction close to lakes could severely impact the quality of water, ground water recharge and biodiversity around it.
In August 2025, the Karnataka government proposed the Karnataka Tank Conservation and Development Authority (Amendment) Bill, 2025, which seeks to reduce the size of the standard 30-metre buffer zones around some water bodies. The Bill was passed in the monsoon session of the Karnataka legislature but has been strongly criticised by citizen collectives and environmentalists in the state’s capital, Bengaluru.
This Bill aims to amend the Karnataka Tank Conservation and Development Authority Act (KTCDA), 2014, for area-wise buffer zones around lakes, based on the size of the lake. This would then allow for the construction of “certain public utility activities such as roads, bridges, electrical lines, and water supply lines.”
Buffer zones are designated areas around lakes and stormwater drains where construction and other development activities are not permitted. “They create land and water boundaries where flora and fauna can flourish, which would not exist otherwise,” says Shubha Ramachandran, a water sustainability consultant.
She elaborates that buffer zones increase the places around the lake where percolation is possible. “When there is solid waste dumping, it [buffer zone] provides space for it [waste] to be further filtered before it comes into the lake or is diverted. The wider the buffer zone, the better,” she says. Moreover, in urban areas, buffer zones also provide some spaces for recreation.
Currently, Section 12 of the KTCDA prohibits any unauthorised construction, any commercial, recreational or industrial complexes or houses or carrying on any industrial activity within 30 metres from the outer boundary of the water body.
The new Amendment introduces size-based buffer zones for water bodies. No buffer zone is required for a water body up to 0.05 acres. For those between 0.05 and 0.10 acres, a buffer zone of one metre is mandated. Those ranging from 0.10 to 1.00 acres, a three-metre buffer, and between 1 to 10 acres require six metres and so on. Areas above 100 acres or more will have a 30-metre buffer zone.
The Karnataka government stated, in a press release, that this incremental buffer distance has been “framed using a scientific approach” to facilitate the natural inflow of water into lakes of varying sizes. However, citizen collectives, lake groups, environmentalists and experts have raised concerns about the Amendment’s impact on the water bodies.
Last month, Karnataka Governor Thaawarchand Gehlot returned the Bill to the state government seeking more clarification after receiving objections from the Bengaluru Town Hall (BTH) group, a citizen collective.
One of the primary concerns that activists and environmental experts have about the Bill is the impact on groundwater around the lake. “Currently, it [the buffer zone] is about 30 metres from the edge of the lake, which allows for a stretch of green space next to the water body in Bengaluru, where only 4% of the area is green cover. This space helps recharge the groundwater, so there should be more such areas, not less,” says Shashank Palur, senior hydrologist at WELL Labs.
Further, the proposed Bill states that the government can use the area within the buffer zone for public utility services such as the construction of roads, bridges, electrical lines, water supply lines, or pump houses and sewage treatment plants (STP). Sandeep Anirudhan, convenor of the Bengaluru Town Hall group, questions this, emphasising that the buffer zone should remain a no-development zone filled with vegetation. “Roads or any other construction should not be permitted,” he says.
“The role of buffer zones is to protect the quality of water in the lake/tank and the ecosystem of the lake. Hence, only activities addressing these concerns should be allowed in the redefined buffer zones,” says Palur.
Motivation behind the reduction
Experts and activists have also pointed out that the Bill could be a way to allow real estate plans. Given that land is an important resource in Bengaluru, Palur also says, “This does look like a development push from the real estate angle.”
However, Minister for Minor Irrigation, N.S. Boseraju denies these allegations. Boseraju tells Mongabay-India that there will be no real estate activities. “We will only do government activities for betterment, such as constructing STPs, which will not affect biodiversity.”
He elaborates that the reason for this change to incremental buffer zones is because the standard buffer zone size is disproportionately applied to small water bodies as well. “In Mangalore, Udupi and other regions in the state, some tanks, which are about half an acre, are smaller than the buffer zones,” he says, adding that the people living in the villages there have requested reducing the buffer zones for smaller water bodies as any kind of land use, including their houses in that area, are considered encroachments.
He adds, “We have more than 41,800 water bodies in the state. Out of those, more than 22,000 are in the Panchayat system. These are all small villages with one to five-acre water bodies. It is here that people want smaller buffer zones instead of the standard 30-metre one.” He compares the situation with that in cities such as Bengaluru, where water bodies are significantly larger and require the standard buffer zone. “In Bengaluru, water bodies are mostly 100 acres, and some are spread across 50 acres, so there won’t be much change for those,” Boseraju says.
His numbers are contested by Palur who estimates that only about 35 lakes in Bengaluru’s municipal area are 100 acres or above. The government, however, presents a different number.
Boseraju also adds that the state has looked into buffer zones in 15 other states before formulating the Bill. “In Tamil Nadu, the buffer zones for water bodies are three metres, and it’s about 10 metres in Telangana,” he says.
However, Palur cautions that comparing buffer zones across states can be misleading as it lacks context. “For instance, Telangana has a higher buffer requirement for small lakes than what Karnataka has now,” he says. He also explains that in northern India, the soil below the lakes is much more conducive to recharge, so there might not be a need for buffer zones to put more water into the ground. However, in southern India, there are clay-lined water bodies where recharge is slow, so they require more open space to increase recharge.
Impact on the environment and people
The new size-based criteria for buffer zones have also raised questions about the effects on the state’s ecology. In their addendum to the Memorandum to the Governor, the BTH group stated that if this Bill becomes law, it will cause “irreversible damage to the ecosystems of 45,000 lakes” and “chopping of crores of trees” across the state.
This will impact the systems depending on these resources, especially agriculture, leading to a food and water security crisis, Anirudhan explains. “For irrigation, farmers depend on these lakes, which store the rainwater. If you shrink their buffer zones, then there will be a reduction in potential clean water entering these lakes. If their health is affected, so will the food production of the state, which will impact lakhs of farmers,” he says.
Aside from the buffer zones around lakes, according to the recent Urban Development Department’s notification, buffer zones around rajakaluves or stormwater drains will also be redefined. According to the proposal, for primary drains, the buffer zone will be reduced from the current 30 metres to 15 metres. For secondary ones, from 15 metres to 10 metres and for tertiary drains from 10 metres to five metres.
While the overflowing or flooding might not be an issue with the city’s lakes, the buffer zone reductions will impact the rajakaluves. Most of the lakes in Bengaluru are artificial, says Palur. “It is a cascading tank system. One lake fills up, it flows to the next one, and this continues. But near natural water bodies, there is a chance of water overflowing from the sides, which won’t happen in a system of tanks.”
However, the main challenge with the rajakaluves or the stormwater drains is that they overflow. “They submerge the areas that are adjacent to them. This means that the closer you have development around the rajakaluves, the more at peril you’re putting people living in the area, whether it’s for disease, life, or livelihood,” Ramachandran explains.
The way forward
For the citizen groups and experts, one of the main issues has been the lack of public consultation. Anirudhan emphasises that on major issues, the government should, in principle, hold a public consultation and consult experts. “However, we are not aware of any such consultation,” he says.
Ramachandran says it’s better to stick with the original 30 metres and ensure the largest possible buffer for all the lakes. “But if there is a need to amend it for a particular lake, then there should be a system in place to figure out the reason and impact appropriately,” she adds.
The motivation behind this reduction plays a role. “For instance, if reducing the buffer zone of a particular lake can significantly ease traffic in the area, then it can be a conversation. So, there is a need to look at buffer zones on a case-by-case basis,” Ramachandran explains.
According to Palur, the water bodies’ hydrological, geotechnical, and ecological aspects should be considered, and experts should be consulted. “For this, you need to create baseline studies on how shrinking the buffer zones will impact biodiversity around water bodies, and even the air quality,” he elaborates.
Ramachandran calls for more transparency and involvement of the public and experts regarding the Bill and emphasises that these decisions should be taken in “an honest, collective and participatory way.”
Read more: The city of lakes battles a deepening water crisis
Banner image: Ulsoor lake in Bengaluru. Image by Ramesh NG via Wikimedia Commons (CC BY-SA 2.0).
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