INTRODUCTION
Prime Hook National Wildlife Refuge (Prime Hook) in Sussex County,
Delaware, was established in 1963 under the authority of the Migratory Bird Conservation Act with the explicit purpose of providing habitat for migratory birds. It supports approximately 300 avian species and is a key stopover and wintering area for shorebirds, wading birds, and waterfowl in the Atlantic Flyway. It also provides six major wildlife-oriented recreational opportunities such as hunting, fishing, wildlife observation, photography, environmental education, and environmental interpretation.
Prime Hook includes nearly 2,300 acres of tidal salt marsh, a rapidly diminishing habitat type, and boasts some of the largest freshwater impoundments along the east coast. These impoundments were created in 1988, total 4,200 acres, and are managed to provide a diversity of freshwater plants not commonly found in such close proximity to the Atlantic Ocean.
ISSUES
Four distinct impoundments (Units I–IV) are separated by levees and water control structures that restrict saltwater intrusion into the central Units–II and III–while retaining tidal influence into Units I and IV. Natural and manmade dunes that stretch along the eastern boundary of Prime Hook improve control by isolating the system and preventing the Delaware Bay from reclaiming areas of historic tidal marsh.
Over the last several years, however, a series of Nor’easters has accelerated degradation of the levees and destroyed portions of the barrier dunes, thereby increasing the frequency and duration of saltwater intrusion into Units II and III. Corrective action to restore the infrastructure is estimated to cost millions of dollars. The cost for long-term management is estimated to be even higher.
Adjacent landowners have been impacted as well. Neighboring agricultural producers have already lost forested buffers due to increased salinities, and the levees are the only land access to a privately-owned beach community positioned between the eastern boundary of Prime Hook and the Delaware Bay. These homes and cottages are in jeopardy of becoming inhabitable with the loss of the barrier dunes and access levees.
CONSIDERATIONS
Tidally-influenced wetlands are dynamic. Each tide carries with it sediment that accretes (i.e. builds up) in areas where sediment from previous tides has settled. Tides also reclaim sediment from coastal wetlands, thereby causing marshes to naturally ‘migrate’ landward and seaward at varying rates over time.
Marsh migration at Prime Hook is stalled. The existing wetlands are settling naturally but have not received inputs due to the barrier dunes and levees. Likewise, there is little room for their movement inland. The landwater interface at many locations within Prime Hook is the public private boundary as well. NT Prime Hook NWR Sea-level rise (SLR) presents additional challenges in coastal Delaware, specifically at Prime Hook. Even conservative SLR predictions suggest that a significant portion of the land base at Prime Hook will be under water during the next 100 years. It is also likely that the impoundments would revert to open water for an unspecified period of time due to bottom consolidation. Near-term remediation could provide an immediate fix; however, the inevitability of SLR impacts on this system requires long-term consideration of strategies that match its ecological trajectory.
WHAT DU IS DOING
The impacts to habitat, waterfowl, and personal property and the costs associated with any remediation at Prime Hook must be carefully considered. However, the potential impacts to migratory birds are not fully known. If Prime Hook reverts to open water there will likely be a significant shift in habitat from freshwater to saltwater vegetation. There are obvious tradeoff s for waterfowl with each scenario.
The U.S. Fish and Wildlife Service (Service) is in the process of developing a Comprehensive Conservation Plan (CCP) for Prime Hook, which will outline mid- and long-range management goals. Among other topics, the CCP will include a preferred action and several alternatives regarding the impoundments and dunes. The Service has set a release date of October 2011 for the CCP, and will be holding public meetings to inform the general public on the process and solicit comments on the draft. Official written comments will be accepted as well.
DU’s Conservation staff will review the CCP when it is released and provide recommendations accordingly, and encourages DU members to do the same.
In the meantime, DU Conservation is gathering information so that we can provide the most informed suggestions to the Service when the CCP is released. DU Conservation is currently engaged with the Delaware Division of Fish and Wildlife and the University of Delaware to investigate the predicted changes in food availability and energetic carrying capacity in coastal impoundments and salt marshes as a result of SLR, and is evaluating similar issues in peer-reviewed scientific journals and from first-hand accounts from DU staff, partners, and landowners located in coastal communities across the country. Regardless, DU will incorporate the best available information when providing our recommendations.
As always, DU is concerned about wetland impacts to waterfowl and other wildlife, hunters, and landowners and will continue to make informed, science-based decisions with issues such as Prime Hook. Please consult
www.fws.gov/northeast/primehook/ or
www.ducks.org/delaware for more information on Prime Hook and to get the latest on the CCP process.
Download this briefing statement in PDF format
Contact information:
KURT ANDERSON, Regional Biologist
Ducks Unlimited Annapolis Office
34 Defense Street, Suite 200, Annapolis, MD 21401
(Phone) 410-224-6620
(Fax) 410-224-2077