Project to restore N.J.'s marshes uses new method: Spraying mud

At a Stone Harbor salt marsh, engineers work on a restoration plan that involves spraying sand and muck over marshes.
At a Stone Harbor salt marsh, engineers work on a restoration plan that involves spraying sand and muck over marshes. (ED HILLE / Staff Photographer)
Posted: August 27, 2014

Saltwater marshes along the Jersey Shore and Delaware Bay, like marshes everywhere, are in trouble.

For many reasons, including sea-level rise, they're becoming less marshy and more watery. They're drowning.

New Jersey, partnering with the Army Corps of Engineers and conservationists, has begun an $8.2 million pilot project that could not only restore the marshes, but also save money and solve other problems along the way.

The new miracle method: Spray mud.

In the Intracoastal Waterway behind Stone Harbor and Avalon, a dredge is sucking up sand and muck that has clogged the channel since Hurricane Sandy blew through.

Normally, the dredge "spoil" is transported to a "confined disposal facility," where it eventually forms a big hill. (The mounds on Nummy Island, between Stone Harbor and North Wildwood, are not natural.)

Now, however, in what may be one of the messiest recycling projects going, some of the channel sediment is being mixed with water and sprayed over nearby marshes.

The idea is to hose enough sediment on them to rebuild them, yet not so much that the plants cannot grow back through the new material.

Though they may seem little more than smelly ooze, marshes provide valuable habitat, protect water quality, and serve as fish nurseries. They also offer critical storm protection to Shore communities, along with evacuation routes, by blunting the effects of waves.

In general, coastal areas fringed by marshland suffered less damage from Sandy than areas that were not, said Danielle Kreeger, science director of the nonprofit Partnership for the Delaware Estuary, a congressionally designated science group.

One problem with marshes is that they cannot keep up with sea-level rise - about a foot over the last century in New Jersey. Scientists predict the rate will accelerate with climate change.

Much of the sediment in places like the Intracoastal Waterway originated in marshes, having been robbed from them by erosion and storms.

"We're putting it back," said Monica Chasten, a project manager for the Army Corps of Engineers.

The corps' mission is to keep the navigational channel clear, not restore the ecosystem, she said. "But now we're trying to look across the lines and see how one can benefit the other."

The standard practice of transporting dredged material to disposal sites is expensive, and the state is running out of space. But what makes the new process tricky - the reason New Jersey went with a pilot project instead of adopting methods already employed in Delaware, along the Louisiana coast, near Baltimore, and in New York's Jamaica Bay - is that all sediments are different.

Some are sandy, some silty, and each has its own best use. (Contaminated sediments are impermissible.) And marshes are particular. An eight-inch topping is generally considered optimal. But for each project, scientists analyze the marsh and the muck, tweaking the thickness.

State regulations vary, too. Typically, officials are aghast at anything that could be interpreted as "filling in" a marsh.

So while the sediment spraying "sounds very simple," said DEP biologist Laurie Pettigrew, acting regional superintendent for the Bureau of Land Management, in reality "it's a little more challenging."

Still, proponents are so optimistic about the process - "thin-layer placement" - that similar projects are in the works in the state. The American Littoral Society is leading an effort to spray Sandy-damaged marshes in Cape May and Cumberland Counties. The Forsythe and Cape May national wildlife refuges also are making plans.

"It could protect the marshes, protect the communities, and solve some of the dredging channel problems," said Tim Dillingham, the Littoral Society's executive director.

Funding for the pilot includes a $3.2 million grant from the Department of the Interior - part of $103 million in post-Sandy coastal resilience grants - plus matching funds. Along with the Corps of Engineers, partners include the state Department of Transportation and the nonprofit Green Trust Alliance and Nature Conservancy.

Also part of the project, a higher, sandier habitat will be created for black skimmers, a state-endangered bird, and marshes rebuilt near Fortescue, on Delaware Bay.

In all, about 90 acres of marsh will be restored.

The project, meanwhile, will produce a $3 million saving, since the sediment will not have to be transported to a disposal site.

"It's really, really promising," said Metthea Yepsen, coastal restoration manager for the New Jersey Chapter of the Nature Conservancy, a project partner. "It will make dredging less expensive, and restoration far less expensive."

But for all of the method's purported attributes, it is not a quick fix.

In the first months, it's "pretty darn awful," said Bart Wilson, a scientist with the Center for Inland Bays in Delaware, where a similar project began last year restoring 47 marsh acres near Indian River Bay. "It looks like someone took a giant fire hose and spread mud everywhere."

Two years will pass before enough plants poke through so that the marsh starts looking like its old self again.


sbauers@phillynews.com

215-854-5147 @sbauers

www.inquirer.com/greenspace

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