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Forum 8 (May 22, 2015): Megaproject Pros, Cons

On May 22, the Hampton Roads Adaptation Forum discussed hypothetical megaprojects that could be engineered to protect Virginia’s coasts from floods and storms.

Flood wall in Richmond, VA, is one example of an engineered solu

Flood wall in Richmond, VA, is one example of an engineered solution to controlling flood water. ©Joe Potato/istockphoto

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By Jugal Patel, Student Correspondent

Do big problems need big solutions?

The question arose as experts at the Hampton Roads Adaptation Forum discussed rising seas and sinking land in coastal Virginia. On May 22, the conversation focused on hypothetical megaprojects that could be engineered to protect Virginia’s coasts from floods and storms.

Adaptation practitioners envisioned structures to protect residents from high water during storms, ranging from smaller flood walls shielding individual neighborhoods, to structural behemoths with opening and closing sections that would span the mouth of the Chesapeake Bay.

Hosted by Old Dominion University (ODU), Virginia Sea Grant (VASG), and the Hampton Roads Planning District Commission, the forum brought together about 60 attendees, including ecologists, engineers, hazards specialists, scientists, and public officials.

Speakers discussed the design, operations, maintenance, benefits, and tradeoffs of such undertakings. A primary issue for any large engineering projects is how the region would fund and maintain them. Another is making sure different levels of government share the same goals.

“There has to be regional and intergovernmental alignment,” says Michelle Covi, VASG extension staff at ODU and an organizer of the adaptation forums.

The need for alignment was echoed by Michelle Hamor, a floodplain manager for the Norfolk District of the US Army Corps of Engineers. As part of her duties, Hamor often responds to requests from local, non-federal sponsors to conduct studies that increase regional resilience.

“Any project, especially one that seeks federal funding, should address vulnerabilities identified within a hazard mitigation plan, be included within a regional strategy, measurably reduce risk, and reduce the need for mitigation funding in the future,” Hamor said.

If installed, flood walls and storm surge barriers could reduce flood risk from the sea for residents in coastal Virginia. However, such structures do not address flooding from precipitation or sea level rise. They may also come with ecological and water quality tradeoffs.

Some of those tradeoffs were discovered through a study conducted by the Virginia Institute of Marine Sciences (VIMS), funded by the National Science Foundation, which VIMS researcher Molly Mitchell presented at the forum.

The study modeled a hypothetical storm surge barrier placed across the opening of the Chesapeake Bay in alignment with the Chesapeake Bay Bridge Tunnel. The research team evaluated the physical, environmental, and economic impacts that the theoretical structure would have on the Bay’s watershed.

While the study found potential economic benefits as the modeled barrier reduced flooding and flood losses throughout most of the Bay during storms, Mitchell noted that the benefits should be weighed against the cost of building and maintaining such a structure.

Major hydrodynamic or ecological impacts in the Chesapeake Bay were avoided in the model when the sections of the barrier were closed only a few times and for short periods. Some ecological unknowns remain, however, such as the structure’s impact on species that migrate into the Bay during storms.

While the megastructures have some appeal, Mitchell says, “There are a variety of other adaptation options, such as barriers across smaller river systems or increases in coastal marshes and forests, which should be evaluated, too.”

The goal is a balance of green and gray approaches (“gray” refers to engineered solutions with materials like steel and concrete)—and local policies. Covi adds, “Planning, zoning, and managed retreat are effective tools that should be considered equally with engineering strategies.”

The Hampton Roads Adaptation Forum includes meetings and educational events for practitioners who address sea level and flooding issues in Hampton Roads. The next forum, focusing on nuisance flooding, is scheduled for July 27, 2015.