Sandy the latest in a series of environmental blows suffered along Delaware Bay
CAPE MAY — It began with a one-two punch from Hurricane Irene and Tropical Storm Lee in 2011. Then Hurricane Sandy provided a knock-out blow of sorts to the Delaware Bay oyster.
“Fifty to seventy percent of them died,” said David Bushek, a Rutgers University associate professor of marine and coastal sciences.
Almost 300 scientists, educators, environmentalists, policy-makers and other interested parties are here at The Grand Hotel this week for a conference on the state of the Delaware Estuary. The Partnership for the Delaware Estuary is sponsoring the four-day “Science and Environmental Summit.”
While there was some good news as experts gave presentations on the state of the estuary that covers parts of New Jersey, Delaware and Pennsylvania, including the Delaware Bay and Delaware River, much of the news is not good.
Oysters need a balance between saltwater and freshwater. Bushek said Irene and Lee put so much freshwater in the bay that oysters died in large numbers. Sandy offered less rain and the tidal push drove salty ocean waters up the bay, spreading two oyster diseases that thrive in saltwater, MSX and Dermo.
Sari Rothrock, a science and policy fellow with the partnership, said the one, two, three punch of the storms caused the worst damage to the oyster beds in 60 years.
Clay Sutton, who has studied raptors and other birds on the Maurice River for 25 years under research sponsored by Citizens United to Protect the Maurice River and its Tributaries, said the storms also decimated some bird species as the flooding killed the small mammals they feed on.
“The prey base is at an all-time low and we’re seeing all-time low numbers of hawks,” Sutton said.
While studies are ongoing, an estimated 70 percent of the habitat horseshoe crabs use to spawn on the bayshore has been wiped out. This could impact migrating shorebirds that feast on the horseshoe crab eggs each spring.
“Everyone around the estuary is impacted, from Trenton at the top all the way to Cape May and Lewes (Delaware),” said Rothrock.
Rothrock said sea level rise, land subsidence, and wetlands losses are factors in the damages being caused by coastal storms. The partnership is not just interested in wildlife. It also wants to protect communities on the bayshore and the rivers leading to the bay and it has some innovative ways to combat the changes taking place.
One such project is called “Living Shorelines.” It uses low-tech green technology to stem erosion. Rothrock said four communities including Maurice River Township (Cumberland County), Lewes and Wilmington in Delaware, and Chester, Pa., are interested in the program.
The pilot project, built in 2010, was done at the Heislerville Wildlife Management Area in Cumberland County. It included lining the shoreline with mats and tubes made of coconut fibers. They catch the sediment and are seeded with saltwater cord grasses to make a vegetative seawall of sorts. Mussels and oysters are planted in front of the wall to form a shellfish reef and reduce wave energy. A hard wall like a bulkhead redirects wave energy to the bay floor where it can cause erosion but the promise of a natural seawall is to allow the shoreline to shift somewhat while still protecting property.
The cost per linear foot is less than a bulkhead and Rothrock said the living wall weathered both Irene and Sandy while fostering more marine life than a solid wall. Sandy washed out road and dikes in the area but the living shoreline was not damaged.
“This is about using green infrastructure to make it less vulnerable to impacts like flooding and storms. We don’t know if it will have success everywhere but in Maryland you can’t put in a bulkhead unless you prove a living shoreline won’t work. It’s an option but not the magic bullet. It’s not going to save everything,” said Rothrock.
While the ocean side got most of the national publicity, a bulletin board at the conference titled “Storm Stories” showed the bay got hit just as hard. Participants were invited to post their stories and pictures of damages from Irene, Lee, Sandy, and the Dec. 21 high tides dubbed the “Mayan floods.”
The submissions included houses and bulkheads leveled in Cumberland County, a muskrat lodge flatted in Salem County, roads under water in Aston, Pa., two dikes ruined in New Castle, Del., a parking lot in Wilmington, Del. under water, dead oysters, damaged beaches that horseshoe crabs spawn on, and many others.
Partnership Executive Director Jennifer Adkins said the larger picture is that sea level rise, land subsidence and storms are impacting the wetlands that line the estuary along with a lot of people. More than 15 million people rely on the Delaware River and its tributaries for drinking water.
Tidal waters have risen one foot in the last century and are predicted to rise two to five feet over the next 100 years. Only five percent of the original tidal wetlands remain and 25 percent of what is left is expected to disappear in the next century.
“As sea level rises, wetlands can migrate inland, but they can’t do it if they are blocked by roads and buildings,” said Adkins.
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