Main Street Tunnel technique, whereby the tunnel was excavated, the concrete poured, and the structure buried, on top of which the canal channel was built. This avoided costly boring beneath an active waterway; the structure cost C$11 million. This price was split 50–50 between Transport Canada and the St. Lawrence Seaway Authority. The tunnel opened with a parade featuring the Welland Police pipe band and various officials on the morning of May 20, 1972. Main Street Tunnel The Main Street Tunnel, located in Welland, Ontario, Canada, is an underwater tunnel, carrying Niagara Road 27 and the unsigned designation of Highway 7146 under the
George Wallace Tunnel built in sections and floated to the proper positions, then sunk. Each section was sunk next to the previous section and joined underwater. When all sections were connected, and concrete set into place, they were pumped dry and finished out. The depth of clearance is 40 ft (12.2 m) for the ship channel over the tunnel. This is the same clearance as the older Bankhead Tunnel. The tunnel was officially opened to traffic on February 9, 1973, after $50 million ($275.6 million in 2017 dollars) was spent to construct it. It was named after George Wallace, the Governor of Alabama