The restoration of Prime Hook National Wildlife Refuge, one of the biggest and longest-running challenges for Delaware environmental managers, is finally nearing implementation, wetlands experts heard last week.
The U.S. Fish and Wildlife Service, which owns the southern Delaware preserve, has determined that it can return the 10,000-acre site to its original salt marsh state by closing four breaches in the dunes abutting the Delaware Bay and creating a series of drainage channels that will encourage natural tidal flows.
The plan to close the breaches with sand dredged from offshore is designed to allow the native salt marsh to begin to regenerate after years in which it was often submerged by seawater rushing in from the bay, flooding the adjoining community of Prime Hook Beach, and sometimes washing over its main access road to the west.
FWS officials hope to begin rebuilding the dunes on a 6,000-foot stretch of shoreline in the fall and winter of 2014-2015, according to Susan Guiteras, a biologist for the Coastal Delaware Refuge Complex, which also includes the Bombay Hook preserve.
Guiteras told a conference of wetlands managers at Dover Downs that the FWS has decided to go ahead with the work after extensive hydrological testing showed it was possible to achieve the agency’s goal of restoring the salt marsh by closing all breaches while removing remaining tidal controls to facilitate natural flows.
Residents of the isolated community of Prime Hook Beach have suffered repeated flooding of their homes and land, while being unable to drive on the low-lying Prime Hook Road during high tides or storms since the first of the breaches opened up in 2006.
Further holes in the bayshore dunes opened up during subsequent storms, most recently Hurricane Sandy, which created two more openings in October 2012.
Although the planned dune repairs should help prevent the flooding, there is no guarantee that it will, Guiteras said in an interview.
“This is no guarantee whatsoever that they won’t have to deal with any flooding,” she told Delaware Public Media.
She said the repairs are being done primarily to restore wildlife habitat that was degraded by the creation of massive freshwater impoundments during the 1980s to attract migrating wildfowl.
“We would have planned to restore the salt marsh even if there was no community there,” she said.
Since the dunes breached, the impoundments have been inundated by seawater, destroying their original purpose, and flooding the properties of local residents and farmers.
The FWS, working with Delaware’s Department of Natural Resources and Environmental Control and the U.S. Army Corps of Engineers, wants to rebuild a natural system that will sustain itself and not require continuous repairs to the dunes, Guiteras said.
Overall, the project will cost about $40 million, all of which is coming from the federal government. Delaware will provide in-kind assistance such as wetlands permits, but there will be no cash support for the project from the state, she said.
Officials intend to replicate a part of the refuge, known as Unit 1, where a dune breach has shown signs of repairing itself because it is bordered by an existing salt marsh.
That part of the reserve, which was not subject to the impoundment building of the 1980s, appears to be resilient to encroaching seas, even given their gradual rise, Guiteras said.
“Unit 1 has been keeping pace with the background rate of sea-level rise,” she said. “We want to build salt marsh that can do that.”
She said the longer-term effects of sea-level rise are unknown, and it’s possible that the restored marshes could be submerged by rising waters in 40 or 50 years’ time but even if that happens it will be worth re-establishing the marshes now because of the defense they offer against storm surges.
“If sea-level rise is contemplated, the best position we could be in is to have a healthy, functioning salt marsh,” she said.
Guiteras estimated that re-establishment of the salt marsh could take five to eight years and will be subject to continuous monitoring. If native salt-marsh vegetation does not re-establish itself, it may be necessary to build up the marsh by pumping in additional dredging spoils.
But the marsh won’t get additional help to begin with, she said. “Enough of the pieces are there to get the restoration going.”
The Army Corps has indicated that Prime Hook is a potential beneficiary of material that is being dredged from the Delaware Bay shipping channel, Guiteras said.
The Prime Hook project draws on the experience of other wetland restoration projects, including that of the Florida Everglades, and is one of the largest of its kind, Guiteras said. The planned work follows a framework laid out in a Comprehensive Conservation Plan, previously published by the FWS.
In opening remarks to the conference, DNREC Secretary Collin O’Mara emphasized the value of wetlands to flood control and water quality, as well as to tourism and agriculture.
One of the major goals of DNREC and private conservation groups is to increase public understanding of the importance of wetlands to the state’s overall quality of life, O’Mara said.
“Most people don’t realize that wetlands provide these values,” he said. “In the end, we will protect what we love, and we will love what we understand.”
By absorbing tidal surges, for example, wetlands help to protect Delaware’s beaches, which play an important role in the economically important tourism industry that supports 20,000-30,000 jobs, O’Mara said.
“We don’t think of these environmental resources as an economic driver,” he said.
While many Delaware wetlands have been degraded by development and agriculture, they face a longer-term but severe threat from sea-level rise. According to DNREC’s recent study on the state’s vulnerability to rising seas, up to 99 percent of tidal wetlands in places like Bombay Hook National Wildlife Refuge may be inundated by the end of the century.
Away from the shore, a plan to create a wetland in flood-prone South Wilmington is an example of the wide-ranging benefits of such projects, and is attracting national attention, O’Mara said.
The proposed wetland park in the Southbridge neighborhood is designed to drain streets that are frequently flooded, and so will help to revitalize an impoverished area and create opportunities for recreation such as bird watching, he said.
“This is becoming a national model for green infrastructure in a dense urban area,” he said.
O’Mara urged policymakers and environmental experts to use plain language to help people understand the importance of wetlands and broader issues like climate change.
At a conference attended by presenters using terms like “hydrogeomorphic variables,” O’Mara said people aren’t going to get it without clearer communication.
“That language is much too complicated for people who are just trying to put food on the table,” he said.
O’Mara spoke as his department released a report on the local effects of climate change, saying that Delaware can expect higher temperatures and more days of extreme heat and heavy rain for the rest of the century.
In southern Delaware, about 70 percent of wetlands, both tidal and non-tidal, have been degraded by housing development, roads, farming, ditches and invasive species, notably phragmites, said Matthew Jennette, a DNREC researcher.
Jennette cited a ten-year study of five watersheds ranging from St. Jones to the Inland Bays, and found that 96 percent of tidal wetlands have suffered from the encroachment of farmland, reducing the “buffer” between the two areas, while 60% have been ditched.
But he denied that officials are asking farmers to surrender the edges of their land to wetland. “We are not suggesting that we should have 100 meter buffers,” he said. “We are saying that activity within the 100 meters impacts the wetland.”
Shawn Garvin, Region 3 Administrator for the U.S. Environmental Protection Agency, said coastal wetlands will be especially impacted by rising seas but that Delaware, through its analysis on sea-level rise, is playing an important role in understanding the issue.
“Delaware really has been a leader in focusing on the effects of climate change,” Garvin said.
