Superstorm Sandy got a lot of East Coast cities thinking about their vulnerability to storm surges, particularly in light of rising sea levels, and what might be done to protect themselves. A study underway in Virginia is examining whether a potential protective barrier might be inspired by some existing infrastructure—Chesapeake Bay Bridge-Tunnel.
Stretching 23 miles between Virginia Beach and the Delmarva Peninsula, the one-time engineering wonder of the modern world spans the mouth of an estuary whose watershed includes major metropolitan areas such as Hampton Roads; Washington, DC; Baltimore; and Philadelphia. As reported by the Virginian-Pilot, scientists at the Virginia Institute of Marine Science are exploring what would happen if a series of flood gates were built along the same route.
The story doesn’t mention whether the flood gate network would be integrated with or independent of the existing Bridge-Tunnel, nor are any design or cost comparisons involved. It’s mainly an attempt to model what would happen if some kind of storm surge barrier existed, and what benefit/consequence trade-offs might result—economic, infrastructure-related, environmental, etc.
These are issues that Norfolk, one of the Bridge-Tunnel’s next-door neighbors, will likely have to grapple with sooner than later, as the region is sinking by .12 inches a year, a natural result of both retreating ice sheets and the meteor crater that created the Chesapeake Bay millions of years ago. That might not sound like much, but combined with rising sea levels, tides reaching Norfolk will be as much as 7.5 feet higher than today—not a good prospect for a low-lying area already beset by more frequent flood events.
The City of Norfolk has already invested in a study that yielded options such as $1 billion network of food gates and stormwater improvements, elevating roads and buildings, or abandoning the most vulnerable parts of the city. There are also the ramifications to consider, spanning everything from landfills to Naval Station Norfolk, the world’s largest naval base.
So while Chesapeake Bay flood barrier study may sound like nothing more than an intriguing thought exercise, the fact that such questions are being asked now rather than in the heady, emotion-fueled days following another Sandy is perhaps its most valuable aspect. Having some fundamental answers in place will help address the more critical, time- and cost-sensitive debates that are as sure to come as the tides themselves.
As Carl Hershner, director of the institute’s Center for Coastal Resources Management, says in the Virginian-Pilot story, “There will be a sudden pressure of political will to fix the problem. We’re working to get out in front of what we think is going to be a public policy question.”