With Metro pillars obstructing the flow of water in Tolly’s Nullah, the state irrigation department has decided to connect the drain with Adiganga at Kamalgazi. The water of Adiganga will then be discharged into river Matla in the Sunderbans.

State Irrigation Minister Subash Naskar said the water of Nullah would be diverted from Garia station road beside the EM Bypass to Adiganga. He also said that since the flow in Adiganga is sluggish due to silting, the ministry would soon undertake excavation of the river.

A source in the state irrigation department said the primary survey of the project has begun and the minister had held a high-level meeting with engineers last week.

“The flow of water in Tolly’s Nullah will be restored when it could be connected to Adiganga,” said Naskar. The return of the normal flow in the Nullah is the only way to restore the waterbody, he added.

The irrigation department had excavated Tolly’s Nullah in 2000 under the Ganga Action Plan. But deposition of silt in the river bed reduced the depth of the Nullah between Kudghat and Garia in the last nine years, said an official in the irrigation department.

It was not possible to excavate Tolly’s Nullah every five or ten years, said the official.

The Tolly’s Nullah, which originates from Hooghly at Kidderpore, flows through Tollygune to Garia. The width of the river bed varies from 30 to 7 metres. According to Naskar, pillars of the elevated structure of the Metro rail constructed on the Nullah bed from Kudghat to Pranabnagar — a stretch of nearly 6 kms — have obstructed the flow of water.