The Haji Ali-Nariman Point sea link, the last phase of the Western Freeway project, could now be a combination of a sea bridge, a tunnel and a shallow tunnel under Marine Drive. The Maharashtra State Road Development Corporation (MSRDC), the nodal agency for the project, will soon send the suggestion to the state Cabinet for approval.

The first phase — the Bandra Worli sea link — is nearing completion. Bids for construction of the Worli-Haji Ali sea link are under scrutiny and the construction is expected to begin later this year. A final decision on the Haji Ali-Nariman Point connectivity is crucial as the dispersal of traffic from the first two sections will be a challenging task.

S M Gavai, vice-chairman and managing director of MSRDC, said the empowered committee chaired by the Chief Secretary has perused various alternatives suggested by consultants and recommended a sea bridge from Haji Ali to Priyadarshini Park, followed by a deep (drill and blast) tunnel via Malabar Hill to Tambe Chowk and then a cut-and-cover tunnel from Tambe Chowk to Nariman Point.

The shallow tunnel was preferred to a sea bridge for the final section as a sea-bridge along this portion could mar the view of the proposed statue of Chhatrapati Shivaji Maharaj off the Marine Drive coast. The 10.9-km link between Haji Ali and Nariman Point could be constructed on a build, operate and transfer (BOT) basis like the Worli-Haji Ali sea link.

Cut-and-cover tunnelling is a simple and cost-effective method of construction of shallow tunnels; the road is excavated to create a trench and roofed over. A strong overhead support system is required to carry the load of the covering material. “The shallow tunnel would be a four-lane road under the existing Marine Drive. We’re sending the recommendation from the consultants to the Cabinet,” said Gavai.

MP Milind Deora had criticised the decision on a tunnel under Malabar Hill. When asked about the protest, Public Works Minister Vimaltai Mundada said, “We will weigh all options before deciding on the alignment.”