Shoreline Protection

CWPPRA Restoration Technique: Shoreline Protection

Louisiana’s shorelines are eroding at a drastic pace, some at rates up to 50 feet per year. The fertile but fragile soils found in the wetlands are susceptible to wave energy. As land is lost, water bodies merge together, which can increase wave fetch and shoreline erosion. Behind these shorelines lie communities, highways, and infrastructure that are at risk of washing away.

Various techniques to defend the coastline have been tested and applied under CWPPRA. Rock revetments, oyster reefs, concrete panels, and other fabricated materials have been constructed along otherwise unstable shorelines to abate wave energy and reduce erosion. These structures are designed to break waves, and they often trap waterborne sediments behind the structures that, over time, can become new land.

Through the course of the CWPPRA program, advancements have been made in shoreline structures that have helped maintain natural processes while providing critical protection. Such advancements have included using lighter-weight materials that require less maintenance and can be constructed on organic sediments. Other advancements include low-relief structures that are designed to trap sediments and natural breakwaters such as reefs that can self-maintain and support other ecological functions. Other natural shoreline protection measures include vegetative plantings, whose roots help secure soils and can promote accretion. These projects are implemented with consideration for minimizing impacts to the surrounding environment. Although some shoreline structures may look foreign in a natural landscape, they are necessary features that physically protect communities and hold wetlands in place by mitigating the harsh forces that move to destroy them.

BA-26 Barataria Bay Waterway East Side Shoreline Protection

 

Bayou Decade Ridge and Marsh Creation

The Terrebonne Basin is an abandoned delta complex, characterized by a thick section of unconsolidated sediments that are undergoing dewatering and compaction, contributing to high subsidence, and a network of old distributary ridges extending southward from Houma. Historically, subsidence and numerous oil and gas canals and pipelines in the area have contributed significantly to wetland losses. Since 1932, the Terrebonne Basin has lost approximately 20% of its wetlands. Current loss rates range from approximately 4,500 to 6,500 acres/year. This loss amounts to about130,000 acres over the next 20 years. One-third of the Terrebonne Basin’s remaining wetlands would be lost to open water by the year 2040. The wetland loss rate in the area is -0.79%/year based on USGS data from 1984 to 2016.

The proposed project’s primary feature is to create and/
or nourish approximately 504 acres of intermediate marsh adjacent to Lake De Cade and restore 11,726 linear feet of ridge habitat along the northern bank of Bayou De Cade. To achieve this, sediment will be hydraulically pumped from a borrow source in Lake De Cade. The borrow area in Lake De Cade would be located and designed in a manner to avoid and minimize environmental impacts (e.g., to submerged aquatic vegetation and water quality) to the maximum extent practicable. Containment dikes will be constructed around the marsh creation area to retain sediment during pumping. No later than three years post construction, the containment dikes will be degraded and/or gapped. Additionally, the newly constructed marsh will be planted after construction to stabilize the platform and reduce time for full vegetation. It is anticipated that material for the ridge feature will be mechanically dredged from adjacent areas within Bayou De Cade and/or the marsh area and lifted to a crown elevation of +5.0 feet, 25 feet wide, and will be planted.

This project is located in Region 3, Terrebonne Basin, Terrebonne Parish, Lake Mechant Mapping Unit.

This project was approved for Phase I Engineering and Design in January 2017 and is on Priority Project List (PPL) 26.

The Bayou Decade Ridge and Marsh Creation project sponsors include:

• Federal Sponsor: National Marine Fisheries Service
• Local Sponsor: Coastal Protection and Restoration Authority

Keep up with this project and other CWPPRA projects on the project page.

Louisiana Salvinia Weevil Propagation Facility

The invasive plant, giant Salvinia, was first observed in Chenier Plain marshes in 2009. Since then it has spread throughout most of the Louisiana Chenier Plain marshes. This plant can stack up above the water surface to as much as 6 to 12 inches. Under such conditions, oxygen exchange is greatly reduced, and decay of shaded Salvinia can easily cause anoxic conditions in affected areas. As a result, habitat quality of badly infested areas is severely degraded, and may affect many species typical of fresh marshes, including many species of management concern (alligator snapping turtle, mottled duck [including critical brood rearing habitat], wintering migratory waterfowl, black rail, king rail, little blue heron, whooping crane, and peregrine falcon).

LSU Ag. Center has a pond in Jeanerette, La. which is capable of producing weevil-infested Salvinia, but LSU does not have funding to operate a weevil production facility here. Costs associated with this project consists primarily of supplies and one part-time position to operate the pond, coordinate public weevil harvests, keep records of release locations, monitor Salvinia problem areas, assist landowners in conducting weevil release, relay infested Salvinia to new locations, and conduct public outreach to promote the program.

The Louisiana Salvinia Weevil Propagation Facility project is located coastwide.

This project was approved for Phase I, Phase II, and Operation in January 2017.

This project is on Priority Project List (PPL) 26.  

The Louisiana Salvinia Weevil Propagation Facility project sponsors include:

• Federal Sponsor: U.S. Fish and Wildlife Service
• Local Sponsor: Coastal Protection and Restoration Authority

Keep up with this project and other CWPPRA projects on the project page.

 

 

LEEC 2017

The Louisiana Environmental Education Commission, Louisiana Department of Wildlife and Fisheries, and the Louisiana Environmental Education Association hosted the 20th Environmental Education State Symposium on February 3-4, 2017 at the Embassy Suites by Hilton in Baton Rouge, La. The theme of this year’s symposium was “protecting Louisiana’s endangered species.”

The Louisiana Environmental Education Commission (LEEC) provides environmental education news from across Louisiana, including information on environmental education programs, workshops, and grant opportunities.  The state symposium furnished opportunities for formal and non-formal environmental educators from Louisiana and surrounding states to meet and share teaching techniques as well as multiple concurrent sessions for various topics and grade levels. Keynote speaker Dr. Jessica Kastler, Coordinator of Program Development at the Gulf Coast Research Laboratory’s Marine Education Center, used individual cases of endangered species to engage the audience in explorations of the process of science while cultivating environmental stewardship. In addition to the keynote speech, presenters in 15 concurrent sessions provided lesson demonstrations, hands-on workshops, and/or exemplary programs. The Coastal Wetlands Planning, Protection, and Restoration Act Public Outreach Staff was among exhibitors with a multitude of materials to assist teachers of all grade levels in furthering their students’ knowledge in environmental education and coastal protection.

Bayou Grande Cheniere Marsh & Ridge Restoration

Significant marsh loss has occurred south of Lake Hermitage with the construction of numerous oil and gas canals, subsidence, and sediment deprivation. The most significant loss occurred during the 1960s and 1970s. Based on the hyper-temporal analysis conducted by USGS for the extended boundary, loss rates in the project area are estimated to be -1.16% per ear for the period 1984 to 2011.

The goals of the Bayou Grande Cheniere Marsh and Ridge Restoration Project (BA-173) are to restore marsh habitat adjacent to the eastern shoreline of Bayou Grande Cheniere, reestablish the corresponding section of the bayou’s forested ridge habitat along this shoreline, and create terraces to restore marsh in open water habitat. Specific objectives are to 1) restore 302 acres of brackish marsh habitat, 2) construct the marsh platform to an elevation that supports healthy marsh; 3) reestablish 10,625 linear feet of the historic Bayou Grande Cheniere Ridge to an elevation that supports healthy woody vegetation, 4) establish the ridge with diverse native woody species, and 5) construct 12,000 linear feet of terraces to an elevation that will support healthy marsh.

Riverine sediments will be hydraulically dredged and pumped via pipeline to create/nourish approximately 302 acres of marsh. Containment dikes will be constructed around the perimeter of the marsh creation cells. The proposed design is to place the dredged material to a target fill elevation of +3.0 feet which would ultimately settle to an approximate elevation of just under +0.75 feet NAVD88 (Geoid 12A) at TY20. Tidal creeks are expected to form naturally and containment dikes will be gapped and degraded to enhance the naturally formed tidal creeks.

Hydraulically dredged river sediments will be used to restore 10,625 linear feet of the Bayou Grande Cheniere Ridge. The ridge will have 25-ft crown width, a target height of +4.5 ft NAVD88, and side slopes of 1(V):8(H). Herbaceous plantings (e.g., seashore paspalum) will be necessary immediately after construction and bottomland hardwood species (seedlings and saplings) will be planted by Year 3. Funding for tallow control and maintenance plantings is also included.

In addition, 11,700 linear feet of earthen terraces will be constructed resulting in the creation of approximately 10 acres of wetlands benefiting 154 acres of open water. Each terrace segment will be approximately 450 feet long and built to an elevation of +3.0 feet, with a 25-foot crown width and 1(V):4(H) side slopes. The terraces will be constructed with a bucket dredge using in situ material from within the terrace field.

This project is located in Plaquemines Parish west of the Mississippi River near West Pointe a la Hache. Specifically, the project features are south of Lake Hermitage and along the eastern side of Bayou Grande Cheniere.

This project is on Priority Project List (PPL) 23.

The Bayou Grande Cheniere Marsh & Ridge Restoration project sponsors include:

• Federal Sponsor: U.S. Fish and Wildlife Service
• Local Sponsor: Coastal Protection and Restoration Authority 

Keep up with this project and other CWPPRA projects on the project page.

 

CWPPRA

Are you aware of CWPPRA’s Programmatic Benefits?

• Proven Track Record of Project Construction– Over 25 years, 210 approved projects benefiting more than 1,344 square miles (800,000 acres); 108 constructed (16 under construction).
• Responsive– CWPPRA projects are constructed in 5 to 7 years.
• Interagency Approach– Cost-effective projects developed by an experienced interagency team (5 Federal, 1 State agencies).
• Community Involvement– Local governments and citizens contribute to project nominations and development.
• Predictable Funding– Federal Sport Fish & Boating Safety Trust Fund funding to 2021 through fishing equipment taxes and small engine fuel taxes.
• Fiscally Responsible– CWPPRA projects are cost-effective.
• Science Based– CWPPRA’s monitoring program (Coastwide Referencing Monitoring System-CRMS). Demonstration projects “field-test” restoration techniques for future restoration project success.
• Complementary– CWPPRA projects complement other large-scale restoration efforts (i.e., Coastal Impact Assistance Program, State Master Plan, BP DWH Oil Spill Early Restoration and the RESTORE Act).

CWPPRA has been and will continue to be the primary source of practical experience, learning, and agency expertise regarding coastal restoration in Louisiana.

 

Northwest Turtle Bay Marsh Creation

Historic wetland loss in the area stems from shoreline erosion along Turtle Bay and interior marsh loss from subsidence, sediment deprivation, and construction of oil and gas canals. Based on the hyper-temporal analysis conducted by USGS for the extended project boundary, loss rates in the area are estimated to be -0.83% per year for the period 1984 to 2015.

The primary goal is to re-create marsh habitat in the open water areas and nourish existing marsh within the project area. The specific goal of the project is to create approximately 700 acres of marsh with dredged material from Turtle Bay or Little Lake. The total project area is 798 acres, but the entire area will not be filled with dredged material.

The proposed project would create approximately 484 acres and nourish approximately 216 acres. Existing canal spoil banks, emergent marsh, and limited segments of containment dikes will be used to guide the distribution of the dredged material in the western fill area. Complete perimeter containment dikes will be utilized for the eastern fill area. Containment dikes will be gapped to reestablish hydrologic connectivity with adjacent wetlands.

The project will work synergistically with several existing and planned projects on the Barataria Basin Landbridge, an important landscape feature across the central Barataria Basin.

This project is located in Region 2, Barataria Basin, Jefferson Parish, northwest of Turtle Bay.

Northwest Turtle Bay Marsh Creation is on Priority Project List (PPL) 21 and was approved for Phase II Construction by the CWPPRA Task Force in January of 2017.

Northwest Turtle Bay Marsh Creation project sponsors include:

• Federal Sponsor: U.S. Fish and Wildlife Service
• Local Sponsor: Coastal Protection and Restoration Authority 

Keep up with this project and other CWPPRA projects on the project page.

CWPPRA

What are the strengths and the successes of CWPPRA?

• Addresses the urgent need for on-the-ground coastal restoration in Louisiana
• Constructs coastal restoration projects that protect critically impaired wetland areas
• To date, has constructed 108 projects with a total of 152 active projects that will protect and restore approximately 100,000 acres of land
• Has 25 years of experience in coastal restoration, acting as the State’s only consistent Federal restoration funding authority
• Upon completion, projects provide benefits which meet local and state restoration planning goals
• Initiated and supports the State’s only coastwide monitoring program to evaluate the efficacy of restoration projects on an ecosystem scale
• Serves as the foundation for the development of restoration science and identification of project needs that have become the platform for other restoration funding programs

Visit the CWPPRA project page to learn more about successful projects in your area.

Island Road Marsh Creation & Nourishment

The Terrebonne Basin is an abandoned delta complex, characterized by a thick section of unconsolidated sediments that are undergoing dewatering and compaction, contributing to high subsidence, and a network of old distributary ridges extending southward from Houma. Historically, subsidence and numerous oil and gas canals and pipelines in the area have contributed significantly to wetland losses. Since 1932, the Terrebonne Basin has lost approximately 20% of its wetlands. One-third of the Terrebonne Basin’s remaining wetlands are estimated to be lost to open water by the year 2040. There has been a significant reduction in the marsh platform in the vicinity of Island Road (1.60%/year based on USGS data from 1984 to 2011) that has provided some historical wave energy protection. Island Road is the only land access to the Isle of Jean Charles located west of Pointe Aux Chenes which serves unique Native American and minority communities that historically relied on fishing for their livelihood.

The restoration concept provides for the creation and/or nourishment of approximately 383 acres of emergent saline marsh that will form a land bridge along portions of the perimeter of Cutoff Canal, Twin Pipelines Canals, and Island Road.

The proposed project’s primary feature is to create 364 acres and nourish 19 acres of saline marsh. Sediment will be hydraulically pumped from a borrow source near Lake Felicity. Containment dikes will be constructed around the marsh creation area to retain sediment during pumping and will be degraded and/or gapped no later than three years post construction. Half of the newly constructed marsh (182 acres) will be planted following construction to stabilize the platform and reduce time for full vegetation.

The Island Road Marsh Creation & Nourishment project is located in Region 3, Terrebonne Basin, Terrebonne Parish.

This project is on Priority Project List (PPL) 23.

The Island Road Marsh Creation & Nourishment project sponsors include:

• Federal Sponsor: National Marine Fisheries Service
• Local Sponsor: Coastal Protection and Restoration Authority

Keep up with this project and other CWPPRA projects on the project page.

 

Land Loss

Did you know:

If nothing more is done to stop land loss, Louisiana could potentially lose approximately 700 additional square miles of land, or an area about equal to the size of the greater Washington D.C. – Baltimore area, in the next 50 years.

From 1932 to 2000, coastal Louisiana lost 1,900 square miles of land, roughly an area the size of the state of Delaware. The Coastal Wetlands Planning, Protection, and Restoration Act has protected, created, or restored 95, 954 acres of Louisiana wetlands, while greater than 351,676 acres have also been enhanced. CWPPRA is continuing to work toward the resounding success of coastal restoration.
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