Managing Rockefeller’s Natural Resources
The natural resources at Rockefeller Wildlife Refuge have been conserved through biological management for more than 100 years. The property serves as a test site for marsh management strategies to limit saltwater intrusion, reverse marsh deterioration, and provide productive wildlife habitat. Refuge staff also provide guidance on land management to private landowners with marshland property and share their expertise on the wise use coastal wetlands and wildlife and fisheries resources with state, federal, and international organizations.
Marsh Management
Staff manage the marsh on the refuge through manipulating water levels and salinities through water control structures, conducting prescribed burning, and treating selective areas with herbicides. Their management goals are to conserve native vegetation, stabilize water levels, and manage salinities to encourage growth of submerged aquatic vegetation and annual emergent vegetation, to support wildlife, especially waterfowl.
Staff maintain more than 40 water control structures and 200 miles of levees on the refuge. These levees and structures were strategically placed to form thirteen management units on approximately 43,000 acres of the refuge’s 71,000 wetland acres. These units range in size (from 89 to more than 14,000 acres). Each is managed through one of three hydrologic regimes including gravity drainage, forced drainage, or controlled estuarine, which vary based on the extent to which water and salinity levels are controlled in response to meteorological conditions.
The remaining portions of the refuge are not managed and consist of tidal-influenced brackish and saltwater marsh. Every week, staff also monitor water and salinity levels at sites both on and off the refuge to assess and inventory marsh status.
Exotic and Invasive Species
The impact of exotic and invasive species is estimated to be one of the leading causes of species decline in the United States. Exotic and invasive plant and animal species on Rockefeller Wildlife Refuge include Chinese tallow tree (Triadica sebifera), water hyacinth (Eichornia crassipes), Salvinia sp., roseau cane (Phragmites australis), feral hog (Sus scrofa), and nutria (Myocaster coypus).
Chinese tallow trees are primarily found along the chenier ridge and levees within the marsh. Because this species has become naturalized across most of coastal Louisiana, there is no current plan to control or eradicate the species on the refuge. More serious plant infestations are associated with aquatic invasives, such as water hyacinth and salvinia. Hurricanes Rita (2005) and Ike (2007), and more recently Hurricanes Laura & Delta (2020), brought high levels of salinity to freshwater marshes and effectively eradicated infestations on the refuge. However, these species, particularly giant salvinia (Salvinia molesta), have returned via freshwater waterways to the north of the refuge, creating problems for the refuge and surrounding areas. These outbreaks have been successfully controlled by saltwater introductions without compromising marsh health or freshwater areas to the north. Infestations of roseau cane have increased within the Price Lake unit, and treatment with herbicides may be necessary to control this species in the future.
Feral hogs were discovered on the eastern end of the refuge in 2011. Since then, more than 75 hogs have been removed through trapping efforts. Feral hogs will likely be an ongoing management issue, particularly due to their rooting behavior and the subsequent damage to sensitive marsh vegetation and levees. Nutria is an exotic species from South America, but it has become naturalized in Louisiana. The species was originally imported into Louisiana for the fur farming industry in the 1930s and were released into Louisiana’s coastal marshes. Recent hurricanes have helped control nutria populations on the refuge; however, the species could return via surrounding freshwater areas to the north of the refuge.
Coastal Land Loss and Restoration
When Rockefeller Wildlife Refuge was deeded to the state in 1914, the property was approximately 86,000 acres. The most recent survey indicates only about 71,000 acres remain, with 15,000 acres lost primarily due to coastline erosion. Coastal erosion contributes to the loss of 30 to 40 feet per year along the 26 miles of the refuge’s coastline—one of the fastest rates of erosion is near the mouth of Joseph Harbor Canal where rates average about 56 feet per year. Refuge staff have worked extensively with visiting groups to showcase and discuss the extent of coastal erosion on the refuge.
Refuge staff have also worked to reestablish marsh vegetation in permanent water areas on the refuge, through terracing. They have also planted marsh grasses along canals to reduce wave action and associated levee erosion and pumped dredge spoil into marshes that have subsided or turned to open water to create marshes by bringing elevations back to marsh level. Refuge staff have worked with Coastal Wetlands Planning, Protection and Restoration Act partners to introduce freshwater along Highway 82 via additional water control structures and restore more natural flow conditions to the eastern portion of the refuge. This freshwater introduction brings with it sediment deposition, which in turn will help to sustain a healthy marsh, as well as reverse subsidence and erosion.
ME18 Shoreline Stabilization Projects
On December 10, in Baton Rouge, Louisiana the CWPPRA Technical Committee voted and passed funding for construction on ME-18!
Construction on the project began in August 2018 and was successfully completed in May 2020. Additional funds were allocated for an extension to the existing 3.85 miles of shoreline protection. In December 2020, construction began on the extension project and was successfully completed in March 2021, bringing the project total to approximately 4.5 miles of shoreline protection along Rockefeller’s coast.
ME-18 Shoreline Stabilization video
What is it and Why is it Important?
All coastal projects in Louisiana are assigned to a basin and given a number by the Coastal Wetlands Planning, Protection, and Restoration Act (CWPPRA). In the case of this project, ME is the Mermentau Basin and it is the 18th proposed project for this area. ME-18 provides shoreline protection along 3.85 miles of Rockefeller Refuge; in addition, extension projects of ME-18 have added the total to 4.5 miles of protection.
Rockefeller Refuge is a world-renowned research center for the American Alligator and provides space for research on marsh management. It is in the center of the Mississippi Flyway and has millions of birds migrating through this area on an annual basis.
According to the Coastal Education and Research Foundation, Rockefeller is the erosional hotspot of the Chenier Plain in west Louisiana. This area receives one of the highest rates of erosion in the state.
Who to Contact:
- Mark Wingate, US Corps of Engineers
Mark.r.wingate@usace.army.mil
Tel: (504) 862-1957 - Bren Haase, Louisiana Coastal Protection and Restoration Authority
Bren.Haase@la.gov
Tel: (225) 342-2179 - Darryl Clark, US Fish and Wildlife Service
Darryl_Clark@fws.gov
Tel: (337) 291-3111 - Richard Hartman, National Marine Fisheries Service
Richard.Hartman@noaa.gov
Tel: (225) 389-0508, x203 - Karen McCormick, Environmental Protection Agency
mccormick.karen@epamail.epa.gov
Tel: (214) 665-8365 - Britt Paul, Natural Resource Conservation Service
britt.paul@la.usda.gov
Tel: (318) 473-7756
Timeline
CWPPRA Technical Committee will vote for 4 projects on December 10, 2015 in Baton Rouge, La.
What is CWPPRA?
The Coastal Wetlands Planning, Protection and Restoration Act, also called the Breaux Act was created in 1990. This basically became the clearinghouse for coastal projects in Louisiana.
(the following information is from CWPPRA's website: lacoast.gov)
Typically referred to as the "Task Force" (TF), it is comprised of one member from each of five the Federal Agencies and the Local Cost Share Sponsor, which is the State of Louisiana. The Federal Agencies of CWPPRA include:
- the U.S. Fish & Wildlife Service (USFWS) of the US Department of the Interior,
- the Natural Resources Conservation Service (NRCS) of the U.S. Department of Agriculture (USDA),
- the National Marine Fisheries Service of Department of Commerce (USDC),
- the U.S. Environmental Protection Agency (USEPA), and
- the U.S. Army Corps of Engineers (USACE).
The Governor's Office of the State of Louisiana represents the state on the TF. The TF provides guidance and direction to subordinate organizations of the program through the Technical Committee (TC), which reports to the TF. The TF is charged by the Act to make final decisions concerning issues, policies, and procedures necessary to execute the Program and its projects. The TF makes directives for action to the TC, and the TF makes decisions in consideration of TC recommendations.
The District Commander of the USACE, New Orleans District (NOD), is the Chairman of the TF. The TF Chairman leads the TF and sets the agenda for action of the TF to execute the Program and projects. At the direction of the Chairman of the TF, the NOD:
- provides administration, management, and oversight of the Planning and Construction Programs, and acts as accountant, budgeter, administrator, and disburser of all Federal and non-Federal funds under the Act,
- acts as the official manager of financial data and most information relating to the CWPPRA Program and projects.
The Technical Committee
The Technical Committee (TC) is established by the Task Force (TF) to provide advice and recommendations for execution of the Program and projects from a number of technical perspectives, which include:
- engineering
- environmental
- economic
- real estate
- construction
- operation and maintenance
- monitoring
The TC provides guidance and direction to subordinate organizations of the program through the Planning & Evaluation Subcommittee (P&E), which reports to the TC. The TC is charged by the TF to consider and shape decisions and proposed actions of the P&E, regarding its position on issues, policy, and procedures towards execution of the Program and projects. The TC makes directives for action to the P&E, and the TC makes decisions in consideration of the P&E recommendations.
The Chair's seat of the TC resides with the USACE, NOD. The TC Chairman leads the TC and sets the agenda for action of the TC to make recommendations to the TF for executing the Program and projects. At the direction of the Chairman of the TF, the Chairman of the TC guides the management and administrative work charged to the TF Chairman.
Demonstrations of the Project
There was a demonstration phase for the ME-18 project. Below are the three breakwater demonstrations.
Lightweight Aggregate Core
Oftentimes, breakwaters are so heavy they sink in on themselves. The interior of the lightweight aggregate (LWA) breakwater is composed of a neutrally buoyant clay and shale. Therefore, load bearing on the underlying sediment is lighter than a typical rock breakwater.
This site is still actively accreting land and slowing wave energy. Much of the video above was shot at this test section.
Regular Breakwater
This test section was composed of rocks that are typically used to make a breakwater. Due to the soft sediment in this area of the coast, this breakwater has almost sunk below sea level. This test section is not slowing wave energy or accreting land as well as the LWA test section.
Artificial Oyster Reef
A fairly new type of restoration has been implemented on the third test section. Circular interlocking rings were designed and constructed to make an artificial reef. This section has also begun to sink below the water level.
Protecting the Coast - Protects the Parish
Cameron Parish is the most southwestern parish in Louisiana and has steadily been rebuilding since Hurricanes Laura and Delta in 2020.
There are drainage canals throughout the parish, with some of them running through Rockefeller Wildlife Refuge. The lower Mermentau Basin Levee is just over mile north of the proposed project. If this levee were to erode, saltwater intrusion would reach far above Hwy. 82 and into much of the Mermentau River Basin.
Projects that protect the coastline first, can aid in other coastal projects further inland; often marsh creation or freshwater introduction. For example, there are two other proposed CWPPRA projects within a few miles north of this coastal project. Without coastline protection, these inland projects may be imperiled and compromised before they begin.
History of Project ME-18
For nearly a century, coastal erosion has plagued Louisiana's Gulf Coast. In the southwestern parts of the Louisiana coast, the erosion rate is ~47 ft. per year.
The beach is primarily composed of crushed shell (aka, shell hash). Because this material is lighter than sand, this material is easily transported by wind and water. When a heavy south wind produces large waves and high tides, the shell hash is picked up and placed into the marsh immediately behind original beach location. The vegetation where the shell hash becomes deposited is suffocated and dies.
Meanwhile, when the shell hash moves landward, the underlying soft clay/mud material is exposed. This underlying material is highly erosive and once eroded, completes the cycle until the next storm/wind event.
Segmented breakwaters or rockwalls, have been used along Louisiana's coastline for over 20 years. They slow the wave energy from crashing into the coast, and they trap sediment behind the rockwall. Over time, the land builds outward toward the rock wall and land loss is eliminated.
The original design for this project started in 1999. A few years later, the breakwater test sections were set up along the western shore of Joseph Harbor Canal. There were three types of demonstration breakwaters set up. In previous Priority Project List meetings by CWPRRA, this project has failed to be approved for funding and the erosion rate has continued at nearly fifty feet a year
Waterfowl Management
Every November, December, and January, biologists conduct aerial waterfowl surveys over 550,000 acres of LDWF’s coastal wildlife management areas and refuges. These surveys provide useful information, including:
- An index of waterfowl use on public areas in coastal Louisiana
- Insight to the sportsmen and women of Louisiana about waterfowl use on their areas of interest
- Data to inform waterfowl management decisions and activities on public areas.
Staff routinely conduct intensive management techniques throughout the refuge to promote habitat for waterfowl, including hydrologic manipulations (drawdowns/flooding), prescribed burning, and large-scale herbicide treatments.