Bangalore: When intense rains turned parts of Bengaluru into a sort of dystopian Venice earlier this month, with people drenched in boats plying the streets, residents of parts of the city found it all too easy to dry themselves Thanks to a “model” stormwater drain.
Originating near the Majestic region and flowing into Bellandur Lake (which flooded after the deluge), the Koramangala Valley stormwater drainage – or K-100 – is an outlier in a city known for its silt-filled drainage infrastructure. goes.
Unlike most of its closed counterparts, the 12 km drain (which is yet to be completely rejuvenated) was able to do its job The night between 4th and 5th September when the city sank 131.6 mm of rain,
When ThePrint visited on Tuesday, the area around the creek near Shanti Nagar bus station, which is the first phase of the project, looked beautiful, with a sprawling amphitheater, attractive plants and the writing “Citizen’s Waterway” on the walls. Had been. Two men could be seen walking across a small bridge and along a walkway before climbing the stairs to the other side.
Just two or so years ago, the nala was nothing more than a sewer full of garbage, but it got a new lease of life by the Karnataka government inspired by Seoul. upgrade It was decided to upgrade it under the aegis of the Brihat Bengaluru Mahanagara Palike (BBMP), the city’s civic body – of the 10.9 km concrete-covered Cheonggicheon stream.
The results haven’t just been aesthetic.
Naresh Narasimhan, the city architect of the Maud Foundation, who conceptualized the BBMP project, told ThePrint, “The entire drain was blocked very well except perhaps in one spot during last week’s rain.”
K-100 Nala passes through KR Market, Shanti Nagar, Hosur Road, Ijipura, National Games Village, Koramangala, ST Bed Layout and ends at Bellandur. Its watershed covers 32 sq km, and it carries one-twelfth of the city’s sewage/runoff.
“Water was flowing well even while traveling through the old city. Now all the bridges are in the same span, the waterway is clean, there is no silt or solid waste. People are becoming more disciplined and not throwing plastic in the drain as more tippers are available along the stretch,” Narasimhan said.
Today, the K-100 project is being put on hold as a pilot project that can be scaled up to help protect Bengaluru from floods. As it flows through different levels of land use under different conditions, the project provides inputs On how to adapt it to different conditions in a city with a growing population.
Read also: Heavy rains, poor drainage, poor infra – how Bengaluru was hit by a perfect storm and drowned
How did the project start
In 2016, in a landmark decision, the National Green Tribunal rejected Environment clearance and plans approved for Rs 2,300 crore project on Bellandur Lake wetland. The Green Court asked to reclaim and manifold 3.10 acres of lake land besides staying the construction Rajkaluwes Or stormwater drainage has to be restored.
When the NGT ordered the concretization of the entire length of the drain, the civic authorities started looking at ways to rejuvenate the stretch.
The BBMP initiated the project to rejuvenate the K-100 with the help of urban designers and architects at the Mod Foundation based in Bengaluru.
According to BBMP engineering chief BS Prahlad, Rs 150-160 crore has been spent so far on the project, which aims to “bring back 32 acres of public space worth Rs 1200 crore”.
But the project was not without its difficulties.
When the team began work on stormwater drainage, it looked like an open sewer. There was indiscriminate dumping of waste, properties running along the creek emptied their waste directly into it, and industrial waste mixed with sewage and rain water.
“The biggest challenge we faced at K-100 was to change the pipe drainage system from open flow to piped flow. We were able to remove the sewage from the drains and 900 trucks of silt were removed,” Prahlad said.
Eventually, he said, the team was able to restore an earlier shield, which had changed because human waste flowing down storm drains accumulated 2 meters of silt. With this excess silt removed, the drainage system was able to flow smoothly.
“Earlier, the areas along the banks of the drain including Koramangala were getting flooded every year,” They said.
Restoring Bengaluru’s ‘Water Heritage’ With Public Help
With Bengaluru urbanization at a rapid pace, the original Rajkaluwes Or traditional irrigation canals such as the K-100 have become narrow and clogged with obstructions.
Prahlad believes that repeating the process used for the K-100 in these canals could yield good results, but would also require purchases from people.
,[K-100] Definitely a model. But first of all the public should come forward and say that our Rajkaluwes Sewage should be free. If sewage is removed from storm water drains, we can go for siltation and create an artificial river. If there is groundwater enrichment then it will help in reducing the floods and we can bring back the glory of the river system in this city.
Nidhi Bhatnagar, an urban designer at the Maud Foundation, also said that the premise of the project was to connect the city and its people to their “water heritage”, but many are unaware that it even exists.
“If you don’t know if a water body is flowing in a specific location because it has been closed, how can you tell people it’s something theirs?” He asked.
For inspiration, the team looked to examples from China, Korea, and the Philippines.
One aspect that stood out was that public participation is a key aspect of the success of waterway renewal projects.
“What was interesting about [renewal of the] Pasig River It was in Manila that it was heavily relegated to public participation,” Narasimhan said.
In the K-100 project, several city and state agencies worked together and collaborated to create awareness among the people living on either side of the drain.
Now, communities contribute plants to planters along the walls and enjoy the open spaces. As the project has been ongoing for years, the team has observed a significant reduction in sewage and wastewater drainage.
“No plan will work unless you take out sewage, solid waste and silt from existing drains. That’s all you have to do, and 80 per cent of the problem will be resolved,” Narasimhan said. “Encroachment is a part of it. The real big problem is silt, solid waste and sewage and the channel width needs to keep on widening as you go further. ,
Narasimhan said sifting through examples from other countries shows the importance of natural water systems to repair drains and the use of artificial wetlands to clean and filter water.
Narasimhan said, “This is an important thing that we need to bring to India, it is called built wetlands.” “We often believe that the only way to treat wastewater or liquid waste is through expensive membrane-based water treatment plants, which require electricity and doses of chemicals.”
“The guiding principle of this project was that we have to move from gray to green infrastructure paradigm. We should bring the masses to the public infrastructure,” the architect continued.
(Edited by Aswari Singh)
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