Making the Case for Nature

Making the case for nature-based solutions in Virginia’s coastal bays: Quantifying the wave-dampening effects of restored oyster reefs on eroding shorelines

The Nature Conservancy is working with partners and leading coastal scientists to better understand how we can use nature to make coastal communities more resilient in the face of a changing climate.  The Eastern Shore’s unique expanse of Atlantic coastal wilderness offers unparalleled opportunities to study how local communities can benefit from intact natural systems, and the advantages of restoring coastal habitat.  Toward this end, The Nature Conservancy, the Virginia Marine Resources Commission, and dozens of volunteers finished constructing two oyster reefs along eroded shorelines in the Atlantic coastal bays.  The two reef restoration sites consist of 1.4 acres and 1.3 acres, respectively, of dredged fossil shell that was barged and spread (or “planted”) on mudflats fronting the eroding tidal salt marsh shorelines near Oyster, Virginia.  Along two 500-ft stretches of the seaward edge of the two shell plants (for a total of 1,000-ft), volunteers and staff built a series of 144 reef arrays using 4,000 oyster castles, marine-friendly 30-lb concrete blocks shaped like Legos, an alternative reef substrate.

Volunteers building oyster castle arrays at Man and Boy Marsh near Oyster, Virginia. Photo credit: Gwynn Crichton

Volunteers building oyster castle arrays at Man and Boy Marsh near Oyster, Virginia. Photo credit: Gwynn Crichton

One of the goals of this project is to see if the new reef dampens wave energy and slows the rate of erosion along the marsh’s edge.  Conservancy partners at the University of Virginia’s Virginia Coast Reserve Long-Term Ecological Research Project (a National Science Foundation funded project) are conducting research regarding the effects of the reef demonstration sites on wave action to help the Conservancy make a case for the value of natural infrastructure in protecting shorelines.  The research conducted on the reef’s ability to attenuate wave energy will be used to locally calibrate the Coastal Defense app to be released later this winter.  The Coastal Defense app enables users to evaluate and quantify the wave attenuation effects of oyster reef and marsh for select shoreline areas to help identify the best places where restoring these coastal habitats are a viable solution for risk reduction.

Three additional oyster reef projects will be built in spring 2016 at the Chincoteague National Wildlife Refuge and also studied by UVA researchers. These demonstration projects are the foundation of the case we are making for natural infrastructure.  In addition to dampening wave energy, these oyster reefs will also be able to keep pace with sea-level rise, improve water quality, and provide critical habitat for crabs, fish and other marine wildlife over time.  This project is funded by both the U.S. Department of Interior and the National Fish and Wildlife Foundation through funds established by the Disaster Relief Appropriations Act of 2013 designated to support Hurricane Sandy recovery efforts.

Oyster growth on oyster castles after two years at the Box Tree Oyster Sanctuary at the Virginia Coast Reserve. Photo credit: Bowdoin Lusk

Oyster growth on oyster castles after two years at the Box Tree Oyster Sanctuary at the Virginia Coast Reserve. Photo credit: Bowdoin Lusk

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