As docks gets bigger, so do concerns

MARY LANDERS | SavannahNow.com

September 14, 2007 -- Wrack may be the ruin of a stretch of Wilmington Island marsh.

That's wrack as in dead marsh grass that has accumulated in mats up to a foot thick in front of Betsy Cain's and her neighbors' homes. The decaying rafts of dead grass have smothered some of the living Spartina beneath it and left a muddy moonscape at low tide. For weeks this summer it trapped the small boats at Cain's and nearby docks. The wrack is natural. Much like trees shed their leaves, last year's marsh grass dies off to make way for new growth. It normally sheets down the coasts on high tides, dispersing naturally.

But the huge buildup of marsh wrack in that particular spot is not so normal, Cain said.
She points to a nearby dock, recently extended to 980 feet, as the cause. Such long docks are becoming more the norm. The Department of Natural Resources, charged with protecting the state-owned marshlands, puts no overt restrictions on dock length, even though there are concerns about docks' environmental effects, including how they trap wrack.

A boom year for wrack
The effects of wrack buildup may be especially noticeable this year because it's been a boom year for dead grass. "A number of people have commented it's been years since we've seen wrack buildup like this," said Susan Shipman, director of the Coastal Resources Division of the Department of Natural Resources. She speculated that a late spring and subsequent higher-than-normal high tides may have contributed to the phenomenon. It's not just docks, but any obstruction, including natural elevations, that make wrack pile up, Shipman said. "Right near our (Brunswick) office on 17 there's an incredible layer of wrack where the marsh meets the road shoulder," she said.

In any year, boom or not, wrack decays in the marsh, adding needed carbon back to that ecosystem. Or it lands on the beach and assists natural dune formation. It even adds carbon to the ocean. "Lots get rafted out to sea," said Clark Alexander, professor of geology at the Skidaway Institute of Oceanography. "In our research vessel we've gone through piles of the stuff a mile across."

Ecological debate
Mark Dana, who owns the 980-foot dock near Cain, points to wrack's ecological role as a reason its buildup is not a problem. "A perfect analogy is you can look at a snake and say it's ugly, while others say it's important to the ecosystem," he said. But Cain's argument is an ecological one, too: A man-made structure is causing the buildup of too much dead grass in one spot and killing the live marsh beneath it. As marshfront property owners, the Danas applied for and received a permit last year from the Georgia Department of Natural Resources to extend their existing dock from 210 feet to 980 feet, where it would meet up with deeper water at Tom Creek.

Cain learned of the dock plans only after she saw a construction barge at the site in December. No prior notice was required because she doesn't own property next to the Danas. She said she spent about a month talking with DNR and trying to engage the Danas about her concerns. But by January, when that effort looked largely unsuccessful, she, her husband, David Kaminsky, and neighbor Larry Gibson sued the Department of Natural Resources, the U.S. Army Corps of Engineers and the Danas to halt the dock construction and re-evaluate the application. They argued the dock was not in keeping with neighboring docks, none of which are longer than 220 feet, and that it wasn't appropriate for their shallow tidal basin.

"It's too much impact environmentally to justify this one property owner getting to one pocket of deeper water," Cain said. Both the length of the dock and its position on an east-facing marsh would contribute to wrack buildup behind it, predicted Altamaha Riverkeeper James Holland, who gave a sworn statement in the case. "I have observed firsthand the accumulation of marsh wracks in and around the pilings of these docks, which in turn leads to the creation of huge expanses of dead and dying vegetation and the resultant creation of huge areas of mud flats devoid of natural flora and fauna of the marsh system," he said.

U.S. District Judge William T. Moore, ruling on the basis of whether the DNR properly followed its procedures for approving dock applications, allowed the permit to stand. "The court is not empowered to substitute its judgment for that of the agency," he wrote.

Wrack wrangling
After the legal loss, Cain watched Holland's predictions start to materialize this summer. The wrack made a huge and eventually fetid compost pile around their docks, reaching across six lots. At times it looked like an enormous windshield wiper had swept across the marsh, starting at the outermost point of the Danas' dock and pushing the wrack toward land. Cain was used to wrack buildup, but never this much. "We always get wrack across the upland part of the marsh," she said. "Every year I push it off. It's never been a lot. The DNR said people who care about the marsh push it off when it collects." This summer the wrack was more than she could push, although she tried, wading out into the marsh as early as 3 a.m. to take advantage of tides. She feared that if she didn't persevere, wrack would smother the marsh grass on the banks of small creek beds and those creeks would silt in. "We had about 10 acres of the stuff," she said. "It was phenomenal."

Cain called for reinforcements in the form of wrack wrangling parties where volunteers, up to eight at a time, added their muscle to hers and pushed the dead grass out to a marsh creek where the tide could take it away. "I spent the entire summer with volunteers clearing the wrack off the marsh this year in order to salvage the marsh in front of our houses," she said. Dana said he pushed out wrack a "reasonable" number of times.
Labor Day weekend storms that brought up to 14 inches of rain to Wilmington Island flushed away much of the wrack, dumping it on property south of the newly extended dock.

Cain is convinced the wrangling efforts made a difference. "If we had done nothing, all that marsh to the (neighbor's) boat house would be dead," she said earlier this week as she pointed across the marsh that fronts her home. "It's been an impossible task, but we've done it." She continues to push out wrack, heading into the marsh when the tides can assist her efforts.

More research needed
Alexander and Shipman aren't certain wrack buildup is benign. More research is needed, they said. Alexander and his colleague Mike Robinson studied the growth of docks on Wilmington Island, where from 1970 to 2000 the number of docks increased from 174 to 301. As those docks have proliferated, they've also gotten longer because sites with easy access to deep water have already been snapped up. The Danas' dock is not the longest on the island, although the closest one of a similar size is about a mile away on a different creek, Cain said. Alexander and Robinson looked at how dock shading affects the growth of marsh grass under and beside the structures. That study is already affecting policy. New rules issued in July for the type of fast-track permit the Danas received include restrictions on the total area of a dock, although there's no restriction on length, per se. Even though area restrictions weren't required at the time, a concern over shading did affect the Danas' dock, which they reduced from a 6-foot width to 4 feet to reduce shading effects.

For wrack buildup around docks, the evidence so far is anecdotal, Alexander said. "Docks that extend out easterly from islands tend to act as traps for marsh wrack as it's being transported," he said. The effects could be greater than those of shading, but again, research is the only way to know that. "Marsh wrack has a more direct and immediate effect on Spartina because it's laying right on it," Alexander said.

The DNR is monitoring the wrack buildup aerially to see how long it takes for smothered marsh grass to grow back, Shipman said. The results of that and other wrack research may further affect dock policy. But Alexander, who served for eight years on the state's Coastal Marshlands Protection Committee - the entity that issues permits for community and commercial docks and marinas - isn't counting on it. "Even if you had evidence, it's a long shot they'd start restricting dock length," he said. "You have to balance the potential for wrack buildup against the perceived right to wharf out to deep water."
Policy change is exactly what Cain is advocating in light of the trend toward longer docks to smaller creeks. She'd like to see a wider public notice before recreational docks are built. And she wants more scrutiny of possible effects on the publicly owned marsh.

"We don't really understand why long docks are allowed to kill this shared resource," she said.