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.

Wetland Plants

Plants are a vital piece of healthy and sustainable wetland ecosystems. Plants are the base of the food chain and can build new layers of organic material on top of wetlands which helps them keep pace with subsidence and rising waters. Wetland vegetation reduces erosion primarily by dampening and absorbing wave and current energy and by binding and stabilizing the soil with roots. Coastal wetland plant species are indicators of soil and hydrologic conditions. The amount and salinity of water in an area influence which plants grow there. Scientists often classify Louisiana marshes into four types: fresh, intermediate, brackish, and saline.

The Coastal Wetlands Planning, Protection, and Restoration Act puts native wetland plant benefits to use through restoration techniques that include vegetative plantings. Vegetative planting projects are used both alone and in conjunction with barrier island restoration, marsh creation, shoreline protection, and sediment and nutrient trapping restoration techniques. These projects use flood-and salt-tolerant native marsh plants that will hold sediments together and stabilize the soil with their roots as they become established in a new area.

BA-38 Barataria Barrier Island Complex Project: Pelican Island and Pass La Mer to Chaland Pass Restoration

 

 

 

 

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.

RAE Conference 2016

Restore America’s Estuaries (RAE) is a non-profit organization dedicated to the protection and restoration of bays and estuaries as essential resources for our nation. RAE member organizations restore coastal habitats in 11 estuaries and 16 states nationwide. RAE is also involved in the economics and valuation of estuaries, blue carbon, living shorelines, national advocacy, and a wide range of coastal restoration issues. The Coastal Society (TCS) is an organization that is dedicated to actively addressing emerging coastal issues by fostering dialogue, forging partnerships, and promoting communications and education. TCS is comprised of private sector, academic, and government professionals and students who are committed to promoting and effectively improving management of the coasts and ocean.

Restore America’s Estuaries and The Coastal Society hosted the 8th National Summit on Coastal and Estuarine Restoration and the 25th Biennial Meeting of The Coastal Society on December 10-15 at the Hilton Riverside Hotel in New Orleans, La. The Summit is an international gathering encompassing all disciplines within the coastal and estuarine restoration and management communities. RAE and TCS  worked with 200 partnering and supporting organizations to develop the Summit program and welcomed more than 1,200 attendees from the restoration and management communities: non-profit and community organizations, Indian Country, academic and research institutions, businesses with an interest in the coast, and agencies from all levels of government. Restoration and management-interested groups or individuals gathered for an integrated discussion to explore issues, solutions, and lessons learned in their work. The theme of the 2016 conference, “Our Coasts, Our Future, Our Choice,” reflected the environmental, economic, and cultural importance of our coasts to residents of surrounding areas and to the nation as a whole.

To initiate the conference’s 550 oral presentations in 110 sessions, as well as 200 poster presentations, the Marc J. Hershman Opening Plenary session on “The Gulf of Mexico- Proving Ground for Regional Recovery Strategies” discussed how restoration in the Gulf is faring as enormous resources start to pour in. The subsequent days highlighted climate change, economic vitality, as well as coastal communities across the nation and the ecosystems they rely upon through sessions, a coastal film series,  and science communications coffee breaks. The closing plenary session covered “Changing Tides: What the New Congress and Administration Mean for Advancing Coastal Restoration and Management” with a panel discussion from leaders in coastal conservation, communications, and climate change policy. Among the 80 exhibitors was the Coastal Wetlands Planning, Protection, and Restoration Act. The CWPPRA exhibit debuted two new posters in the “Protect Our Coast” poster series campaign with accompanying banners in our photo booth, in addition to an array of available CWPPRA publications. As a follow up to the previous Brown Pelican and Louisiana iris posters, a coastal sunset scene and blue crab were each depicted. Participants were able to select from a variety of props to hold or wear while posing in front of the campaign poster banners. Participants posted their photos on multiple social media platforms with the campaign hashtag #ProtectOurCoast.

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Protect Our Coast

Did you know:

CWPPRA debuted a new poster series campaign entitled “Protect Our Coast.”

Each of the four posters in the series depict a coastal related image accompanied by an explanation of how the image connects to wetlands and CWPPRA.

The state’s designated wildflower, the Louisiana iris can be found along the margins of freshwater bayous and sloughs. Having little tolerance for salt water, the Louisiana iris is one of many plant species at risk from saltwater intrusion. Channels dredged through wetlands alter the natural hydrology, resulting in increased salinity and the loss of fresh water vegetation and organisms. CWPPRA hydrologic restoration and freshwater diversion projects regulate salinity and restore the natural hydrology of wetlands, preserving the iris and many other iconic Louisiana plants and animals.

CWPPRA –The Coastal Wetlands Planning, Protection, and Restoration Act– is federal legislation enacted to identify, engineer and design, and fund the construction of coastal wetlands restoration projects. These projects provide for the long-term conservation of wetlands and dependent fish and wildlife populations. Projects funded by CWPPRA are cost-effective ways of restoring, protecting, and enhancing coastal wetlands. CWPPRA has a proven track record of superior coastal restoration science and monitoring techniques in Louisiana.

 

Louisiana accounts for over half of all commercial harvest landings in the Gulf of Mexico. Wetlands, particularly coastal marshes, play an imperative role in the life cycle of about 90% of Gulf marine species, including the blue crab. Providing a protective nursery, wetlands house an immensely diverse quantity of species that rely upon this habitat. CWPPRA aims to continue the protection and restoration of these essential habitats for wildlife, aquaculture, and fisheries.

 

Mangroves, which are used for nesting by Louisiana’s Brown Pelican, are threatened by the loss of Louisiana’s barrier islands. These islands are vanishing at an alarming rate due to man-made changes to coastal Louisiana, including the leveeing of the Mississippi River. Recognizing the ecological importance of barrier islands and their critical role in reducing hurricane storm surge in Louisiana, CWPPRA has played a part in the restoration of nearly every barrier island and barrier headland in Louisiana’s Barataria Basin.

 

Download your CWPPRA Protect Our Coast poster here! Don’t forget to spread coastal awareness by using the campaign hashtag #ProtectOurCoast!

CWPPRA Project Construction

Did you know:

CWPPRA projects are constructed within 5-7 years from initiating engineering and design.

CWPPRA projects are built in a series of phases. The first in the series of phases is Phase Zero which includes conceptual project development. Once a project is approved through the CWPPRA selection process, the project undergoes two subsequent phases to completion. Following the initial phase is Phase One where a combination of pre-construction data collection and engineering and design is incorporated. Lastly, Phase Two encompasses construction, project management, construction supervision and inspection,  and operations, maintenance, and monitoring or OM&M. CWPPRA 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. Over 25 years, the Coastal Wetlands Planning, Protection, and Restoration Act has authorized 210 projects, benefiting approximately 100,000 acres.