Understanding how fresh and salt water circulate within the
existing refuge impoundments, and how water flow and salinity would change in
various marsh restoration scenarios, is a fundamental consideration as we move
forward with the Army Corps of Engineers to design the project. The engineering
firm, Atkins Global, has completed a model that evaluates existing hydrological
conditions in the impoundments as well as two additional alternatives –
maintaining one open breach or filling all breaches. Click here to read the full hydrological report.
The model shows that maintaining an open breach to the bay would
result in the same high water levels and salinity that occur in the
impoundments today as a result of multiple breaches. Atkins found that several
restoration benefits would result if all breaches were closed, including:
In their evaluation, the engineers at Atkins evaluated the
potential for water levels with the breaches closed and also considered the
implications of how the different scenarios would impact flooding of area
communities and roads.
The hydrological modeling complements an
engineering report completed last summer by Atkins Global evaluating the repair
of dune breaches at Prime Hook as the first phase of the marsh restoration
project (see June 25, 2013 update below).
October 31, 2013
The U.S. Fish and Wildlife Service will invest $39.8 million in Hurricane Sandy Disaster Relief appropriations at Prime Hook National Wildlife Refuge. The Service received $20 million of that funding in May to repair beach and dune breaches at the refuge following the storm. On October 24, we received an additional $19.8 million to build upon the dune repairs by restoring a robust marsh environment at Prime Hook that will better withstand the tests of time, future storms and a changing environment. Click here for more information about Hurricane Sandy funding.
In October, we received the peer-reviewed information from Atkins-Global, and a decision has been made on how we will proceed with the design of the dune and breach repair project. We have determined that the best course of action is to completely fill the breach and create a dune crest of approximately six feet above mean sea level.
In the coming months, we will work with the Army Corps of Engineers on a design for the dune repair and full marsh restoration. While the ACOE is doing that work, the Service will fulfill the requirements of environmental review for the project under the National Environmental Policy Act.
The $19.8 million in additional Sandy funding will allow us to proceed with marsh restoration behind the repaired dune line after that work is completed. It will entail building up the marshes' elevation, removing water control structures, and creating channels in the marsh to manage how water flows. After that foundational work has been done, marsh grasses will be planted to make the system more stable and sustainable.
Here is our current timeline of next steps:
- ACOE begins work on dune repair design, possibly with subcontractor
- FWS and ACOE applies for State permits to secure sediment source
- FWS develops scope of work and requests bids for marsh restoration designs
- FWS develops monitoring protocols with State and NGO partners
- FWS establishes agreement with Delaware DNREC to conduct a sediment transport analysis in order to develop an adaptive management strategy for the marsh restoration
- FWS initiates environmental assessment required under NEPA to do the dune repairs and full marsh restoration project
- FWS awards contract for marsh design
- ACOE issues request for proposals from contractors to complete dune repairs, and secures necessary state permits for the dune repair and marsh project
- Work begins on dune repairs and initial marsh platform behind dune line
Fall 2014 to Spring 2015
- FWS initiates monitoring protocols. These data will inform how the system is working and if additional sediment will be needed to restore the marsh plant community.
- Plant grasses (Spartina alterniflora) in marsh
- Begin conveyance channel construction in marsh
- Continue to monitor sediment transport and vegetation
June 25, 2013
We are moving ahead with important steps in planning the marsh restoration project in Units I, II and possibly III at Prime Hook National Wildlife Refuge. Earlier this year we contracted with Atkins Global to complete an engineering study for the Phase I of the project. That full study is available here to read or download (pdf).
The study includes environmental survey results, project overviews, conceptual designs, and potential sites to secure material to build up the dunes and beaches at Prime Hook to complete the initial phase of marsh restoration. It offers a suite of alternatives ranging from partially to fully closing the breaches, and with varying dune and berm widths. These alternatives to complete Phase I would require between 275,000 and 725,000 cubic yards of sand with estimated costs ranging from $3.5 to $11.5 million.
The next step in planning is to apply the engineering data to hydrological modeling this summer. The models will provide us with a sound scientific understanding of how water flows into and out of the marshes, and this information will serve as the foundation for our plan to restore the marshes.
Our goal remains to begin marsh restoration during 2014. The U.S. Fish and Wildlife Service received funding under the Disaster Relief Appropriations Act of 2013, which provided emergency supplemental funding to agencies for repairs and coastal recovery projects following Hurricane Sandy.
March 18, 2013
The U.S. Fish and Wildlife Service earlier this year contracted with an engineering firm, Atkins Global, to obtain information on repairing the dune breaches at Prime Hook as a first phase in a refuge marsh restoration project. The restoration project is the Service’s preferred management action in a comprehensive conservation plan for Prime Hook National Wildlife Refuge that is expected to be approved in the coming weeks.
Atkins Global has calculated that it would take between 500,000 and 800,000 cubic yards of material to complete the first phase of the restoration project.
As part of the same study, Atkins Global created a hydrological model that will help evaluate specific marsh restoration actions. Once the CCP is approved, we plan to move ahead with design and further engineering studies for the marsh restoration.
We will continue to work with Delaware Department of Natural Resources and Environmental Control and the U.S. Army Corps of Engineers to identify sources of material for all phases of marsh restoration. The Service received emergency supplemental funding to repair the dune breach as part of marsh restoration, which widened significantly during Hurricane Sandy.
Winter storms continue to cause extensive flooding at Prime Hook. By restoring Unit II to a healthy and resilient salt marsh, we would create an environment that is more resilient to the influence of coastal storms. We do not expect that the project would eliminate all future flooding of Prime Hook Beach community or its access roads. DNREC has contracted with Atkins Global and another engineering firm to identify short-term solutions for community protection and flood mitigation.
December 28, 2012
Now that the comprehensive conservation plan (CCP) is done, what happens next for marsh restoration?
Our next step is to complete a breach engineering study that will tell us how many cubic yards of material is needed to fill the breach as part of the broader marsh restoration. We need this new information after Hurricane Sandy, since the storm deepened and widened the breach, from about 300 feet to 1500 feet wide.
The same breach engineering study will also develop hydrological models and a design for the breach repair that contributes to marsh restoration.
Once we know how much material is needed for the breach repair and where to place it, we will have a better estimate of how much this breach repair will cost.
Finally, we will need to secure the needed sand and sediment for the breach repair, and the funding to pay for the work.
We do know that we do not have enough sand onsite to repair the breach. The state exhausted the sand supply in October, 2011 when it tried to repair the breach. We will likely have to bring sand from offshore, and that will require a substantial dredging effort.
When will the breach engineering study be complete?
We are finalizing negotiations with Atkins Global, an engineering firm, now. We expect to have a final estimate of the cubic yards of material needed to close the breach by March.
When will you start the marsh restoration project identified in the CCP?
In addition to the breach engineering study and hydrological models, Atkins Global is providing a variety of management options for a marsh restoration plan for the refuge. All of these efforts work together toward restoration called for in the CCP.
We expect the more detailed restoration plan to be complete in 2013. That plan will tell us how much sand and sediment is needed for marsh restoration. We can also then develop a cost estimate for the broader restoration project.
Once the marsh restoration plan is complete, we will need to secure a source of sediment and the needed funding for marsh restoration.
Will you repair the breach independently of marsh restoration?
The breach repair is an important first step toward the broader marsh restoration outlined in the CCP. Ideally, we would secure enough material and funding in order to repair the breach and complete marsh restoration at the same time.
However, we recognize that we may not be able to secure all of the resources needed for both of these important steps to happen simultaneously. Because breach repair will help us to restore the marsh, we intend to proceed with the breach repair once funding and a source of sand are identified, and complete marsh restoration as resources become available.
Are there any short-term solutions to address flooding at the Prime Hook Beach community? When can they be implemented?
The Service intends to restore Unit II to a healthy and resilient marsh that can handle more intense and frequent coastal storms. Marsh restoration will not eliminate all future flooding of Prime Hook Road during extreme high tides and storm events, since floodwaters enter the road through locations other than the breaches.
However, the Delaware Department of Natural Resources and Environmental Control (DNREC) is negotiating a contract with Atkins Global, as well as another engineering firm, to identify short-term solutions for community protection and to minimize flooding to individual homes at Prime Hook Beach. The Service looks forward to the results of those studies, and will partner with the state to implement feasible short-term solutions.
Was funding for Prime Hook NWR included in the Hurricane Sandy emergency supplemental bill?
Yes, $20 million for Prime Hook NWR was included in the Administration's request for emergency supplemental funding for Hurricane Sandy. This is currently the Service's best estimate for the cost to repair the breach that was widened by Hurricane Sandy. The Hurricane Sandy supplemental bill is being considered by Congress. For updates regarding the Hurricane Sandy supplemental bill, please click here.