After years of rebuilding Delaware Bayshore beaches decimated by Hurricane Sandy, the American Littoral Society and its partners have developed a computer tool to help predict where the sand will travel.
Called the Delaware Bay Sediment Transport Analysis Tool, it was created as a team effort between Stockton University’s Coastal Research Center and the Littoral Society, with funding from the National Fish and Wildlife Foundation.
There is no ongoing source of funds for Delaware Bay beach rebuilding, the way there is for Atlantic Coast beaches, said Littoral Society Executive Director Tim Dillingham. The federal government has made a 50-year commitment to replenishing ocean beaches.
Sandy unlocked $4.75 million in federal funds for beach replenishment along the Delaware, but local and county governments will likely have to fund future beach replenishment there.
The tool will help governments and nonprofits make better decisions about where to invest those scarce funds, Dillingham said.
That’s important both to protect wildlife habitat and human communities from rising waters, he said.
The analysis tool uses data collected in the field on conditions that can affect how sediment moves, such as currents and wave heights.
It also includes beach profiles showing elevation changes in the nearshore and coastal zones. Surveys were conducted at 45 sites from North Cape May to Gandys Beach in Cumberland County semiannually for two years, showing where sand is being depleted and where it is building.
“We need to know where the sand will be going in the future,” said Joseph Smith, a researcher with LJ Niles Associates, of Bordentown, which often works with coalition member Conserve Wildlife Foundation of New Jersey.
Smith was speaking to a room full of scientists and government workers gathered at Stockton who are interested in using the tool.
Unlike Atlantic Ocean beaches, those along the Delaware Bay haven’t gotten much attention or replenishment. That is, until Sandy hit in 2012, eliminating about 70 percent of the beaches where horseshoe crabs come to spawn every May.
Immediately a coalition of environmental and government groups formed to conduct emergency repairs, to get ready for the crabs and for the arrival of the red knots that feed on horseshoe crab eggs. The threatened migratory birds stop in May at the Delaware Bayshore to fatten up on the eggs, in order to complete their 9,000-mile trip from South America to the Arctic.
Since then, the Littoral Society and its partners have used a $4.75 million National Fish and Wildlife Foundation grant to restore 2.74 miles of Delaware Bayshore beaches with 201,000 cubic yards of sand, removed 2,000 tons of rubble and built four intertidal oyster reefs, with a fifth being worked on now, the group said. The grant also funded the research tool.
“The reason we started is because of the red knot. That attracted funding that led to all of this work,” said Larry Niles, of Niles Associates.
Goals were to create a good habitat for horseshoe crabs and give birds good access to their eggs, and to restore the horseshoe crab population, which has been dramatically lowered by harvesting for bait, he said.
Replenished beaches have attracted more spawning crabs, he said.
But the beach rebuilding and reef building to lessen the energy of waves hitting the shoreline also benefits human communities, Niles said.
One of the biggest problems historically for Delaware Bay beaches was draining of the marshes for salt hay farms, Smith said.
The draining left the marshes lower than a natural marsh would be, so when there was washover on the beach, sand would be pushed into the marshes and lost. Such practices left bayshore beaches much smaller than they would have been, and in some cases they disappeared altogether.
While there is much known about how sand moves on the oceanfront beaches, there has been little information about it on the bay side, Dillingham said.
DBSTAT is starting with just a few years of data, and it takes 10 to 12 years to develop enough to get a complete picture, said Steve Hafner, of Stockton’s Coastal Research Center.
So it’s important to be able to continue adding to it, he said. That will require additional funding.
To view the interactive tool, seea link with this story at PressofAC.com.