Dredge Work

Karen Westphal was stranded, sitting in the middle of a marsh in southwestern Louisiana, waiting for the weather to behave. “We can only get in and out of the site by boat, so I’m stuck here right now,” she explained as the rain poured down. Westphal, the Atchafalaya basin program manager, which is part of Audubon’s Louisiana Coastal Initiative, routinely chases away alligators while getting caked with mud and bitten by hordes of mosquitoes as she works at the Paul J. Rainey Wildlife Sanctuary.

The capricious elements and relentless critters are a normal part of Westphal’s days in Rainey, where she’s worked for months now, helping to restore the marshlands. There is serious erosion in the sanctuary, and the caretakers worry that it may get worse, but Westphal is using a novel technique to combat it: dredging.

Hurricanes, especially Rita, which hit in 2005, and 2008’s Ike, tore up acres upon acres in the sanctuary, leaving behind ponds connected to waterways and isolated areas of open water where tall cane, spike rush, and grasses once stood. From the air, it’s easy to see the patchwork layout. “People have said it looks like rotting cloth,” says David Ringer, Audubon’s communications director for the Gulf of Mexico and the Mississippi Flyway.

Erosion doesn’t stop after hurricane season, either. Wind-driven water laps at already fragile edges, slowly eating away at the marshland. Without chances for plants to re-root, a marsh can disappear completely into open water. The Rainey Sanctuary, Audubon’s oldest wildlife sanctuary, covers 26,000 acres and is especially important for wintering waterfowl. The recent degradation called for human intervention, and the team opted for dredging, an approach not typically associated with marshes. 

To dredge a waterway, muck from its bed is scooped out or sucked up to make the channel deeper. The idea at Rainey was to take mud dredged from the bottoms of the canals cut through the marshland and deposit it into the bare marsh sites. Plants could then re-colonize the new “land.” Dredges, however, are usually enormous as well as enormously expensive. The Rainey restoration project needed a different kind of dredge, one that could traverse shallow waters, navigate twists and turns, and be used in small areas. 

The Louisiana Coastal Initiative turned for help to a local company, the Javeler Construction Co., which designed a made-to-order, state-of-the-art portable dredge, worth $100,000, and then donated it to Audubon. Funding from TogetherGreen, the organization’s partnership with Toyota, helped the project get under way.

The small dredge, christened the “John James” for Audubon’s namesake, sucked up its first mud in November and has been operating weekly since then. Initially, Westphal and others, including a research group from Louisiana State University, tested the dredging method on about two acres. Considering that hundreds of acres have been damaged, that may not sound like a lot of land. But that’s the point, says Westphal—by reviving small areas of the marsh, the team can avoid disturbing more land or spending millions of dollars.

The effects of the dredging have been immediate. “Almost as soon as we’re done pumping, the birds are waiting,” says Westphal. She has seen American egrets, snowy egrets, and sandpipers returning to the sites, in addition to raccoons and alligators. The native grasses have also started to re-colonize the areas where their roots once dug.

Weather permitting, the team will continue to restore the marsh one plot at a time. “We’re actually creating land and making instant bird habitat,” says Ringer. “It’s a hopeful story.”