Boston Canal/Vermilion Bay Bank Protection (TV-09)

Construction of the Gulf Intracoastal Waterway, Boston Canal, and oilfield canals has greatly increased tidal exchange between Vermilion Bay and the adjacent marshlands to the north, particularly near their confluence with Vermilion Bay. This tidal exchange, combined with the effects of wave action from the bay and boat wake from traffic on the canal, has contributed to significant shoreline erosion along the Vermilion Bay shoreline. This same set of problems has also caused shoreline erosion along Boston Canal, particularly near its confluence with Vermilion Bay.

Rock dikes configured as sediment traps were constructed along the shoreline at the mouth of Boston Canal to promote sediment deposition and protect the shoreline and adjacent wetlands from continued wave-induced erosion. Vegetation was planted along 14 miles of the Vermilion Bay shoreline to act as a wave buffer and decrease shoreline erosion rates.

The project encompasses 466 acres of brackish marsh along approximately 16 miles of Vermilion Bay’s northern shoreline adjacent to Boston Canal. Running from the Oaks Canal to Mud Point, the project is located roughly 6 miles southeast of Intracoastal City, Louisiana, in Vermilion Parish.

Following the construction of the rock dikes, as much as 4.5 feet of sediment has  vertically accreted in the lee, or windsheltered regions, of the structures. The dikes and vegetative plantings have increased vegetation cover, resulting in 57
acres of land growth. The shoreline has been stabilized at the mouth of Boston
Canal.

The survivorship and vegetation cover percentage along the shoreline were more pronounced in areas where native vegetation did not exist. Survivorship and percent cover were least pronounced when marshhay cordgrass (Spartina patens) was planted in established stands of roseau cane (Phragmites australis). Overall survivorship of planted smooth cordgrass (Spartina alterniflora) was over 90% after 12 months. Current coverage is nearing 100%. The 2005 OM&M Report concluded the sediment build-up behind the dike on the east and west sides is continuing and vegetation has taken over the exposed mud flats. Elevation data show an increase in sedimentation behind the rock breakwater.

This project is on Priority Project List 2.

Federal Sponsor: NRCS

Local Sponsor: CPRA

South White Lake Shoreline Protection

The south shoreline of White Lake has been retreating at an estimated average rate of 15 feet per year as a result of wind-induced wave energy. If the shoreline would have continued eroding in the project area, low marsh management levees likely would have been breached, which would have increased interior marsh loss rates in the project area.

This project included constructing segmented breakwaters to protect approximately 61,500 linear feet of shoreline to protect 687 acres of shoreline and interior marsh over twenty years. The breakwaters were constructed with gaps to allow aquatic organisms and water to move freely. An estimated 270,000 tons of stone was placed on geotextile fabric. Material dredged to create a flotation channel was placed beneficially behind the breakwaters to create approximately 172 acres of marsh substrate.

The project is located along the southern shoreline of White Lake from Will’s Point to the western shore of Bear Lake in Vermilion Parish, Louisiana.

Project construction was successfully completed in August 2006.

This project is on Priority Project List (PPL) 12.

The South White Lake Shoreline Protection project sponsors include:

• Federal Sponsor: U.S. Army Corps of Engineers
• Local Sponsor: Coastal Protection and Restoration Authority

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

CWPPRA

Did you know:

CWPPRA has protected, created, or restored approximately 96,806 acres of wetlands in Louisiana.

The Coastal Wetlands Planning, Protection, and Restoration Act has funded coastal restoration projects for 26 years. Presently, CWPPRA has 153 total active projects, 108 completed projects, 17 active construction projects, 23 projects currently in Engineering and Design and has enhanced more than 355,647 acres of wetlands . 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 technique in Louisiana. The success of the CWPPRA program has been essential in providing critical ecosystem stabilization along Louisiana’s coast and has provided pioneering solutions for land loss.

Visit CWPPRA’s website for more information!

New Orleans Landbridge Shoreline Stabilization & Marsh Creation

Since 1956, approximately 110 acres of marsh has been lost along the east shore of Lake Pontchartrain between Hospital Road and the Greens Ditch. One of the greatest influences of marsh loss in the area can be attributed to tropical storm impacts. Wetland losses were accelerated by winds and storm surge caused by Hurricane Katrina, which converted approximately 70 acres of interior marsh to open water. Stabilizing the shoreline and protecting the remaining marsh would protect natural coastal resources dependent on this important estuarine lake, communities that thrive on those resources, the Fort Pike State Historical Site, and infrastructure including U.S. Highway 90. USGS land change analysis determines a loss rate of -0.35% per year for the 1984-2011 period of analysis. Subsidence in this unit is relatively low and is estimated at 0-1 foot/century (Coast 2050).

Lake Pontchartrain supports a large number of wintering waterfowl. Various gulls, terns, herons, egrets, and rails can be found using habitats associated with Lake Pontchartrain, which has been designated as an Important Bird Area by the American Bird Conservancy. Restoring these marshes will protect the Orleans Landbridge and will help to protect fish and wildlife trust resources dependent on these marsh habitats, particularly at-risk species and species of conservation concern such as black rail, reddish egret, brown pelican, mottled duck, seaside sparrow, king rail, and the Louisiana eyed silkmoth.

Borrow material will be dredged from areas within Lake St. Catherine and Pontchartrain to create 169 acres and nourish 102 acres of brackish marsh. Containment dikes will be constructed around four marsh creation areas to retain sediment during pumping. The lake shorelines will be enhanced with an earthen berm to add additional protection from wind induced wave fetch. Containment dikes that are not functioning as shoreline enhancement will be dredged and/or gapped. Vegetative plantings are proposed including five rows along the crown and two rows along the front slope of the shoreline protection berm, as well as within the marsh platform area.

The project is located in Region 1, Pontchartrain Basin, Orleans Parish, flanking U.S. Highway 90 along the east shore of Lake Pontchartrain and areas surrounding Lake St. Catherine.

This project is on Priority Project List (PPL) 24. This project was approved for Phase I Engineering and Design in January 2015.

The New Orleans Landbridge Shoreline Stabilization & Marsh Creation sponsors include:

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

Keep up with the progress on PO-169 and other PPL 24 projects.

 

 

 

 

 

Vermilion Parish Coastal Day

On Friday, June 10th, the Vermilion Parish Coastal Protection and Restoration Committee hosted the first Vermilion Parish Coastal Day in Intracoastal City, Louisiana. Joining the Vermilion Parish Coastal Committee was the Vermilion Parish Police Jury and leaders of Louisiana Coastal Protection and Restoration Authority (CPRA). The one-day event was dedicated to educating local landowners, government officials, and the general public on the success of previous coastal restoration projects as well as current coastal issues in hopes of uniting the community to support the progression of coastal efforts within Vermilion Parish.

Ronald Darby, President of Vermilion Parish Policy Jury, and Kevin Sagrera, Chairman of Vermilion Parish Coastal Committee, welcomed Johnny Bradberry, Executive Assistant to the Governor for Coastal Affairs and CPRA Chairman. Bradberry gave brief updates on current bills and legislation pertaining to coastal projects. Michael Ellis, Executive Director of CPRA, discussed the valuable natural resources available in Vermilion Parish. Ralph Libersat of the Vermilion Parish Coastal Committee presented an overview of Vermilion Parish coastal projects, explaining the critical need to protect what is there now, as opposed to having to recreate land years into the future. Libersat discussed the $92 million of coastal project expenditures in Vermilion Parish to date:$70 million from CWPPRA, $18 million from Vermilion Parish, and $3.4 million from surplus funding, giving a conservative total net benefit of 5180 acres. Libersat highlighted a few CWPPRA projects such as ME-31, TV-12, TV-18, TV-63, and TV-03; Libersat continued by expressing that Vermilion Bay is losing wetlands at a rate of 8-10 feet per day.

Following lunch was a site visit to two restoration project areas along Freshwater Bayou and Vermilion Bay. The first project site was Freshwater Bayou Marsh Creation (ME-31), located west of Freshwater Bayou and north of the Freshwater Bayou Locks; this project is in the Engineering and Design phase to create and/or nourish approximately 401 acres of marsh using dredged material. The second project site was Little Vermilion Bay Sediment Trapping (TV-12), located in the northwestern corner of Little Vermilion Bay at its intersection with the Gulf Intracoastal Waterway (GIWW); this project has been completed and was successful in shoreline protection and sediment trapping with terraces.