Breathing new life into Yamuna floodplains, one wetland at a time

Yamuna floodplains, the Delhi Development Authority (DDA) and the Delhi University (DU) have started developing an integrated floodplain wetlands system at the city’s seventh biodiversity park next to Delhi-Noida Direct Flyway.

The area, located on the western banks of river Yamuna, between the marginal bund and DND Flyway, will soon have large wetlands, 100 metre-wide greenways, 6.8km-long walking trails and recreational parks.

The land-owning agency has roped in CR Babu, who heads the Centre for Environmental Management of Degraded Ecosystems (CEMDE) at the Delhi University, for the project.

Babu, who has been instrumental in the development of six other biodiversity parks in Delhi, said the project has been divided into three main components — Kalindi Colony, DND Flyway and Batla House — which will be developed in a phased manner over a period of five years.

In the first phase, which started earlier this month, Babu and his team have started work in the wetlands near Kalindi Colony and to treat the sewerage from Kilokri drain— one of the major drains running through the floodplains — before it enters into the network of four wetlands.

Babu said, “The wetlands along Kalindi Colony are filled with raw sewage from Kilokri drain and infested with water hyacinths and alternanthera — invasive alien weeds that suffocate the water. We are currently removing these two species of weeds. It is a huge task.”

Explaining the natural filtration process, Babu said the wastewater from the drain passes through an oxidation pond (where oxygen is released into it through photosynthesis) and then to the physical treatment pond (where suspended solid waste is removed as the water passes through pebbles and stones). In the last stage, the water is made to pass through a constructed wetland system which has aquatic plants.

He added, “In the Kalindi Colony component, there are four wetlands that are interconnected. We will develop the constructed wetland system at the point where the Kilokri drain enters the wetland. We have also started the work to desilt the area. The entire process will take at least six months to a year before we can see results.”

While Kalindi Colony and Batla House (wetland in front of the area) will only have wetlands and greenways along it, the DND Flyway component will have recreational spaces. “We plan to develop a 6.8km-long walking trail along the wetland and the DND Flyway. There will be bird safari there. In the DND Flyway component, we plan to develop recreational parks as well,” he said. The DDA has allocated over ₹2 crore for the project.

There are 10 major drains, including Maharani Bagh drain and Kilokri drain, which discharge raw sewage into the wetlands from where it reaches the river, thereby polluting it. The plan is to treat the water from all these drains through a constructed wetland method in which sewerage is made to pass through three levels of filtration.

After the successful revival of Neela Hauz lake in Vasant Kunj by Babu and his team in 2017, it was decided that the constructed wetland method will be replicated at a larger scale.

“The volume of sewage in Neela Hauz is much less as compared to Kilokri and other major drains. The decision to revive wetlands in the western floodplain was taken following the National Green Tribunal’s direction earlier this year. The scale of this project is huge. The cost of treating wastewater through constructed wetland system is much less than a sewage treatment plant,” a senior DDA official aware of the development, said.

Residents of Kalindi Colony, who had approached the NGT highlighting the inaction of authorities over 115 hectares of vacant land being turned into a sewage dump, are happy that the work has started.

“The Kilokri drain was dumping waste and sewage there and it had become a mosquito breeding ground. We are happy that the authorities have take note of our complaint and started the work,” Sanjay Narayen, president of Kalindi resident welfare association, said.

Faiyaz Khudsar, scientist in-charge of Yamuna biodiversity park, CEMDE, said, “Once this biodiversity park is fully developed with a mosaic of wetlands, grasslands, floodplain forests, greenways, recreational parks, bird safari and other landscape elements, it will be a paradise for bird and nature lovers. We expect the wetlands to attract thousands of migratory birds from China, Europe and Siberia. It will also help in recharging groundwater, buffering ambient temperature, besides serving as a filter for point and non-point source of pollution.”