The Chesapeake Bay is a coastal feature of America's east coast fed by the Susquehanna River (among others). It forms the western side of the Delmarva Peninsula and is the sole body of water that makes Norfolk, VA, Baltimore, MD, and Annapolis, MD viable port cities. Crossing onto the Delmarva peninsula can only be accomplished by the Delaware Memorial Bridge, the Chesapeake Bay Bridge, the Bridge-Tunnel, and overland through northern Delaware.
The Chesapeake Bay Bridge-Tunnel connects Virginia Beach to the peninsula down by Cape Charles, and comprises 17.6 miles of US 13 from shore to shore. Because the Bay Bridge-Tunnel is a trestle and causeway fo the bulk of its length, and has several piers (at the tunnel openings), it is much more stable than a suspension bridge of similar length. Besides serving as a land link, the point of the Bridge-Tunnel is not to restrict US Navy and commercial shipping from Norfolk and Baltimore. A suspension bridge might have accomplished this goal, but the Bridge-Tunnel is a cheaper and more elegant solution. It's made up of 12 miles of low-level trestle, 2 one-mile-long tunnels, 2 bridges, 2 miles of causeway, 4 manmade islands and 5-1/2 miles of approach roads. Ships can get through in four places: under the bridges, and over both tunnels. The causeway takes the bridge overland across Fisherman Island, a barrier island which includes the Fisherman Island National Wildlife Refuge.
Each of the manmade islands is about 10 acres each and sits about 30 feet above the waterline, and at the southernmost island there is a restaurant, fishing pier, gift shop (complete with fridge magnets), and coin-operated binoculars. On occasion, you'll see submarines and the occasional aircraft carrier from Atlantic Fleet Headquarters at Norfolk, VA--great fun for the kids and any military buffs. Even more interesting is to approach a tunnel and see a ship which appears to be driving "through" the road ahead due to the curvature of the earth. Birders and ornithophiles may write to the Bridge & Tunnel Commission for permission to stop briefly on each of the islands for bird-watching purposes. I imagine that permission isn't hard to come by.
Some miscellaneous facts and figures, courtesy of the Bridge-Tunnel official website:
- Opening dates: Northbound 2 lanes, April 15, 1964 - Southbound 2 lanes, April 19, 1999. In case you're thinking something pedantic, from 1964-1999, the current "northbound" span was one lane in each direction.
- Building time: Northbound, 42 months - Construction began on September 7, 1960, and the project was opened to traffic on April 15, 1964. Southbound, 46 months - Construction began June 16, 1995, and the project was opened to traffic on April 19, 1999.
- Cost: Northbound, $200,000,000 financed by the sale of revenue bonds. No tax dollars were used. Southbound, $197,185,777 financed by the Chesapeake Bay Bridge and Tunnel District and the sale of revenue bonds. No tax dollars were used.
- TunnelsThimble Shoal Tunnel: 5,734 feet in length
Chesapeake Channel Tunnel: 5,423 feet in length
Tunnel Clearances: 24 feet horizontal; 13 feet 6 inches vertical
- Rock armor for manmade islands: 1,183,295 tons