Navi Mumbai shows BMC how to save visarjan ponds

Gabion wall constructed in a pond at Vashi, Sector-7 for Ganpati idol immersion. Pic/Sameer Markande

While the BMC still struggles to prevent environmental damage caused to ponds due to Ganpati idol immersions, the neighbouring civic body Navi Mumbai Municipal Corporation (NMMC) has found a solution to protect its natural water bodies from pollution and damage.

The NMMC in 2013-14 had constructed gabion walls in all its 19 ponds and created a separate area for immersion. Sunil Desai, a city engineer of NMMC, said, "Because of the gabion wall, the water from the area where the immersion takes place does not enter other parts of the pond."
"We installed a fountain to keep aeration in water, which helps to maintain the quality of water and we are getting good results. To maintain the pond, the corporation auctioned fish rights. Whoever has secured the right to catch fish will maintain the pond," Desai further added.

"After immersions, the chemical colour of the idol mixes with the water, which harms the biodiversity of the pond. However, a partition wall helps in preventing polluted water from entering other parts of the pond," an NMMC official said. "The gabion wall can be constructed at a lower cost than concrete walls. Also, this wall can withstand more water pressure, hence it is more durable," Desai added.

Sunil Godse, deputy commissioner (environment )of BMC, said, "We are working on the rejuvenation of water bodies. This project is in a very basic stage. The BMC will desilt the water body, which will help maintain natural springs. We will study the NMMC project. If it is feasible and environment-friendly we can include it in our project. If all goes as per plan, we will start the pilot project in Sion talao, Shital talao at Kurla and Digeshwar talao in Borivli."

As per BMC data, more than 80 per cent of immersion is done in ponds. In 2019 (Before the pandemic) 1.96 lakh Ganpati idols were immersed in ponds.

Environmentalists have appreciated NMMC's initiative. "I saw some of the ponds in Navi Mumbai. This is a good idea. In Mumbai, the BMC always concentrates on beautification, which is concretising the surrounding area by building pathways and installing lighting and benches. I am sure BMC never thought about pollution-free water bodies," Stalin D, who is a member of the high court-appointed water body conservation committee said.

"The BMC needs to think about the preservation of biodiversity of the water body. This kind of wall can be a solution but the material used for construction should not be heat absorbing as they cause harm to biodiversity," Stalin added.

"As per some reports, there are more than 100 ponds in Mumbai," an activist said.

"BMC passed a proposal of beautification on Charkop pond, which only included construction work in the surrounding area. BMC doesn't have any plan to maintain water quality and save the biodiversity of the pond," he added.