CHENNAI: The state government is looking at a Rs 876.35-crore plan to make a 7.2-km stretch of the Central Buckingham Canal — from Napier Bridge to the Adyar river — navigable again with passenger boats, floating restaurants and cargo movement.
But putting boats back in the 224-year-old canal will require the government to intercept nearly 50 million litres of sewage entering it every day, rehabilitate close to 5,000 families, dredge the heavily silted channel and work around MRTS pillars and low bridges that obstruct navigation and flood flow.
These challenges are outlined in a Detailed Project Report (DPR) prepared by Tamil Nadu Water Investment Company Limited (TWIC). The project seeks to combine water transport with flood mitigation, sewage treatment and commercial development along the canal.
The pilot proposes eight electric boats, each with a capacity to carry 20 passengers, with a tentative fare of Rs 50.
The service and two floating restaurants are expected to earn Rs 2.36 crore annually. Continuous walkways, mangrove restoration, parking, retail spaces and cage fisheries have also been proposed. The pilot could eventually form part of a 55-km inland waterway from Chennai Central to Kovalam and Mahabalipuram, proposed under CUMTA’s Comprehensive Mobility Plan at an indicative cost of Rs 5,500 crore.
The proposal is part of the plan to revive navigation along the Buckingham Canal under National Waterway 4, which connects Kakinada in Andhra Pradesh with Puducherry.
A joint survey in September 2023 identified 19 sewage outfalls discharging an estimated 48.17 million litres a day into the central stretch, up from 11 outfalls carrying 36 MLD in April 2022. Water tests recorded biochemical oxygen demand of up to 54 mg/l, against the target of 5 mg/l required to meet the proposed Class-D standard for sustaining fish and wildlife.
The DPR, a copy of which is with TNIE, proposes diverting sewage from 17 outfalls to two new treatment plants, including a 43-MLD facility on Swami Sivananda Salai and an 8-MLD plant at Greenways Road.
Aeration systems and floating wetlands have been proposed to prevent the treated water from stagnating. About 2.05 lakh cubic metres of silt will have to be removed and 11.6 km of flood walls will have to be rebuilt. Lock gates at the canal’s confluences with the Cooum and Adyar would prevent polluted river water from flowing back during floods.
The DPR identifies 23 bridges as hydraulic bottlenecks, with clearances falling to three metres at some locations. Since MRTS pillars prevent conventional widening at Mandaiveli and Greenways Road, underground cut-and-cover drains have been proposed as alternative flood paths. Together with two straight-cut channels estimated to cost Rs 295.58 crore, the works are projected to reduce the flood-affected area by 45%.
The project will also require the rehabilitation of 4,924 families occupying 11.4 acres within the canal’s right of way. The indicative rehabilitation cost is `107 crore, though biometric verification is yet to be completed.
TWIC expects the project to earn `77.14 crore annually against operating expenses of `30.44 crore. Its financial model, however, depends largely on selling 34 MLD of treated wastewater to industrial and commercial users, which is projected to bring in `49.64 crore a year. The remaining revenue is expected from boat services, restaurants, parking, retail leases, fisheries, solid-waste processing and water credits.
The restoration is also governed by a Madras HC order directing the state to demarcate the canal’s original boundaries, remove encroachments and prevent sewage discharge.
