The first large, prefrabricated section of a new traffic tunnel planned in Virginia began floating down the Chesapeake Bay from Baltimore on Tuesday.
Only a few feet of the concrete structure showed above the water as three tug boats pushed and pulled it south through the day — another 26 feet submerged below the surface.
"It's like an iceberg," said Petty Officer Jonathan Lindberg, a spokesman for the U.S. Coast Guard in Baltimore.
The Coast Guard escorted the tunnel piece and its tugs from Sparrows Point — where it was built by joint-venture partnership SKW Constructors — to near the Chesapeake Bay Bridge.
In coming days, the tunnel piece will continue on to Portsmouth, Va., for placement in the Elizabeth River this fall. The work is part of a $1.5 billion project to build a new two-lane Midtown Tunnel under the river between Norfolk and Portsmouth.
The new tunnel will run parrallel to the existing Midtown Tunnel, increasing traffic capacity between the cities, officials have said. The project is expected to be completed in August 2018.
A dry dock where the first six of 11 planned tunnel sections were constructed in Sparrows Point was flooded on Monday so the sections could be moved into the Baltimore harbor for mooring, according to the Virginia Department of Transportation.
Movement of the first piece began Tuesday morning, but progressed slower than expected — at about 1 knot, rather than the expected 3 knots — in part due to poor weather conditions, Lindberg said.
The Virginia transportation department estimated it would take between four and seven days for each piece to make the journey from Baltimore to Portsmouth, and that transporting all of the pieces would take five to seven weeks. Construction of the remaining five pieces will follow.
Officials said the project is supporting hundreds of jobs, including some at Sparrows Point.