Cameron Prairie National Wildlife Refuge Shoreline Protection (ME-09)

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The management levee between the GIWW and the
Cameron Prairie National Wildlife Refuge was in danger
of breaching as a result of erosion from boat traffic in the
GIWW. If breaching had occurred, wave energy from the
GIWW and salt water would have entered the organic,
freshwater wetlands.

A 13,200-foot rock breakwater was constructed 50 feet
from the northern bank of the GIWW to prevent waves
caused by boat traffic from overtopping and eroding the
remaining spoil bank.
The project’s effectiveness is being evaluated by shoreline
movement surveys and by comparing pre-construction and
post-construction aerial photographs for changes in marsh
loss rates.

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This project is located in Cameron Parish, Louisiana, on
the north shore of the Gulf Intracoastal Waterway
(GIWW), approximately 7 miles southeast of Sweet Lake
and to the east of Louisiana Highway 27 at its intersection
with the GIWW. It encompasses 640 acres of fresh marsh
and open water.

During 1993-97, while the project area had a 4.9% increase in
water coverage due to management for waterfowl, the
reference area remained unchanged.

The results of shoreline monitoring indicate that the project
has protected 13,200 feet of shoreline, along with 247 acres of
marsh north of the dike. This protection is expected to accrue
throughout the life of the project for a net restoration of at
least 23 acres. Monitoring has shown that the GIWW’s
northern shoreline advanced 9.8 feet per year in the project
area while retreating at a rate of 3.0 feet per year in the
reference area, indicating that low sediment availability does
not prohibit wetland creation behind rock dikes on navigation
channels.

To date, the project has exhibited success. It is expected that
the project area will continue to accrete new wetland area
between the spoil bank and the rock dike, further
safeguarding the adjacent wetland area from encroachment by
the GIWW.

This project is on Priority Project List 1.

 

The Federal Sponsor is USFWS

The Local Sponsor is CPRA

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Little Vermilion Bay Sediment Trapping (TV-12)

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High winds and waves prevent GIWW sediments transported down the Freshwater and Schooner bayous from settling and forming the basis of vegetated marsh. This same wind and wave energy also increases shoreline erosion rates.

This project involved the construction of a series of vegetated terraces to diminish waves in Little Vermilion Bay, helping to increase sediment deposition and reduce the rate of shoreline erosion. A pattern of channels was dredged 100-feet wide and 6-feet deep to beneficially distribute sediment from the GIWW through the Freshwater and Schooner bayous. Dredged sediments were used to construct 23 earthen terraces with a combined length of 23,300 feet. After settling, the average height of the terraces was 3.5 feet above mean sea level.

The bases of the terraces were planted with 20,450 containers of smooth cordgrass (Spartina alterniflora).

The design allows commercial and recreational fisherman to access the project area, and it stimulates fishery production by creating new habitat and increasing shoreline length.

In 1998 alone (prior to the project’s completion) 40 acres of wetland habitat were created.

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This project is located in the northwestern corner of Little Vermilion Bay at its intersection with the Gulf Intracoastal Waterway (GIWW) in Vermilion Parish, Louisiana. The project area encompasses 964 acres.

Monitoring is underway and preliminary observations show that the terraces are growing in width, and bay depth between terraces is decreasing indicating marsh expansion in the project area.

This project is on Priority Project List 5.

The Federal Sponsor is NOAA NMFS

The Local Sponsor is CPRA

Thankful for Wetlands

When celebrating Thanksgiving tomorrow, be sure to think about all of the ways wetlands provide for you and yours. Whether you enjoy the serene experience of watching a sunset through bald cypress trees, catching redfish in the marsh with your family, or simply love a good shrimp po-boy, Louisiana wetlands provide a huge number of services to millions of people daily.

In addition to protecting our cities from storm surge, wetlands of all kinds host tremendous species diversity, are highly productive, and allow for many types of recreation. Louisiana provides seafood nationwide. All of our most profitable species use wetlands for some part of their life cycle. [1] For example, shrimp spawn in estuaries, crawfish spend their whole semi-aquatic lives in freshwater wetlands, and oysters occupy coastlines while providing some wave attenuation and water filtration. CWPPRA and our partners see oysters as an alternative method to protect our some parts of our coast with artificial reefs that can also be harvested, making them a highly sustainable food source. Some foods we receive from wetlands aside from seafood include turtles and ducks in some cases, rice (a staple in many cultures worldwide), and a wide array of other plants for their tubers or berries.

Beyond the food, though, wetland benefits include flood protection to our major cultural hubs and carbon sequestration. Sequestering carbon makes wetlands wildly productive and an ally in the fight against global climate change. [2] CWPPRA was written into law in 1990 to help preserve these bountiful ecosystems so they can continue to thrive and benefit people in Louisiana and beyond. This holiday season, even if you are not eating any seafood during your feasts, you are benefitting from wetlands, so say a thank you for all of those natural areas that give us so much.

[1] https://www.epa.gov/sites/production/files/2016-02/documents/economicbenefits.pdf

[2] https://imedea.uib-csic.es/master/cambioglobal/Modulo_V_cod101611/Coastal%20sinks%20(seagrasses_mangroves_saltmarshes)/Bibliography_coastal/Chmura%20et%20al%202006.pdf

 

Whiskey Island Back Barrier Marsh Creation (TE-50)

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Gulfside and bayside erosion has resulted in the narrowing of Whiskey Island (and the entire Isles Dernieres chain) as the two shorelines migrate toward each other, resulting in a 68 percent decrease in average width for the Isles Dernieres. Within 100 years, the entire subaerial portion of the Isles Dernieres barrier island system is expected to disappear except for small land fragments associated with the western end of Whiskey Island and the eastern end of East Island. However, some estimates project the Isles Dernieres will disappear much earlier. Other predictions suggest that, without restoration, Whiskey Island could become a subaqueous sand shoal by 2019. Another CWPPRA restoration project, Whiskey Island Restoration (TE-27), which included placement of dredge material, vegetative planting, and sand fencing, was completed in 2000.

The goal of the TE-50 project is to increase the longevity of the previously restored and natural portions of the island by increasing the island’s width. Increasing the island’s width will help to retain sand volume and elevation. Approximately 319 acres of back barrier intertidal marsh habitat, 5,865 linear feet of tidal creeks, three 1-acre tidal ponds and 13,000 linear feet of protective sand dune were created by semiconfined disposal and placement of dredged material. The sediment was dredged from a sediment source in the Gulf of Mexico near the island. The area was planted with native marsh vegetation to colonize and protect the newly-placed marsh soil.

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Whiskey Island, one of five islands that make up the Isles Dernieres barrier island chain, is located 18 miles southwest of Cocodrie in Terrebonne Parish, Louisiana. The island is surrounded by Coupe Colin to the west, Whiskey Pass to the east, Lake Pelto, Caillou Boca, and Caillou Bay to the north, and the Gulf of Mexico to the south.

The CWPPRA Task Force approved funding for construction (phase 2) at the February 13, 2008 Task Force meeting. Construction began in March 2009 and initial construction was completed in November 2009.Vegetative plantings were installed at the project site in June of 2010 and October 2011.

This project is on Project Priority List 13.

Federal Sponsor: EPA

Local Sponsor: CPRA

Living Shorelines

According to NOAA, one of our managing agencies, a living shoreline is “A protected and stabilized shoreline that is made of natural materials such as plants, sand, or rock.” [1] In some situations, living shorelines are a better option than hardened shoreline protection because they have more movement of natural sediment, the ability to grow, and the obvious aesthetic value of a natural area.

‘Living shorelines’ can refer to multiple restoration techniques and coastal environments; for CWPPRA, a living shoreline can mean vegetative planting on a marsh creation cell or using a shoreline protection barrier that promotes oyster reef growth. Living restored shorelines help maintain the integrity of ecosystems, but they also provide benefits to recreation and potentially to commerce. One big push in restoration over the past few years has been artificial oyster reefs which provide wave attenuation, natural water filtration, and a harvestable population of oysters for the seafood industry. [2]

Illustration, Courtesy of NOAA [1]
Vegetated marsh provides similar benefits to artificial oyster reefs and is a tried-and-true restoration strategy. Many marsh creation projects will naturally revegetate thanks to seed banks in borrow sites but some need management to limit invasive species. In more vulnerable sites, CWPPRA actively plants native species like smooth cordgrass and California bulrush to give them an advantage against invasive populations.

CWPPRA understands that successful restoration projects, including shoreline protection, help keep ecosystems intact and productive. A changing coast means we need changing solutions, and we will strive to find better alternatives to maintain the natural environment.

[1] https://oceanservice.noaa.gov/facts/living-shoreline.html

[2] https://www.smithsonianmag.com/innovation/storms-get-bigger-oyster-reefs-can-help-protect-shorelines-180967774/

Featured image from https://oceanbites.org/oyster_reef_restoration/

 

Hurricanes

This week marks 13 years since Hurricane Katrina, an event some citizens of Louisiana are still recovering from. We may have all heard the name, but do we know what a hurricane is, how wetlands are affected, and how coastal landforms can decrease hurricane impacts?

“Hurricanes” are low-pressure tropical storm systems that differ from other storms in severity as well as location. A hurricane is a storm with winds above 64mph accompanied by heavy rain that originates in either the NE Pacific or the N Atlantic Ocean (the oceans that touch the USA). Due to a phenomenon called the Coriolis Effect, hurricanes rotate counter-clockwise, whereas a southern hemisphere storm would rotate clockwise. Hurricanes develop a characteristic “eye of the storm” in the center, which is an area of low pressure and low wind. Just outside of the eye is the most severe weather, the eyewall, with winds reaching up to 210mph in the strongest storms! Hurricane “category” ratings are as follows:

  • Category 1: 74-93mph
  • Category 2: 96-109mph
  • Category 3: 110-129mph
  • Category 4: 130-157mph
  • Category 5: >158mph

Hurricanes develop over areas with warmer waters, typically nearer the equator, and move away from the equator. [1] Coastal Louisiana is hit by hurricanes on an increasingly regular basis, and those hurricanes all develop in the North Atlantic Ocean in late summer and fall. Our “Hurricane Season” occurs from June through November each year. [2] Several aspects of hurricanes pose major threats to our wetlands statewide. High winds can topple trees, rip up shrubs and grasses, and move sediments around. High rainfall can cause flooding in areas that are not well-adapted to high-water conditions. Storm surge can push saline seawater into brackish and freshwater systems. Hurricanes cause massive disturbance in coastal wetlands, but wetlands are a crucial barrier that protects major cities from taking as much damage. CWPPRA works to combat land loss and protect the future of coastal Louisiana.

Some CWPPRA projects restore barrier islands, which are natural defenses that develop in the Deltaic Cycle. Barrier islands lessen storm surge during hurricanes, bearing the brunt of the waves. Sadly, they cannot provide perfect protection because they are degrading, but they are not the last line of defense. We still have coastal marshes that are great at storing water and acting like a speed bump to storm surge. It is estimated that each mile of coastal marsh decreases storm surge by about a foot. Unfortunately, many coastal marshes are decaying into open water and are no longer protective barriers. CWPPRA will continue to restore wetlands and nourish barrier islands to #ProtectOurCoast!

 

[1] https://en.wikipedia.org/wiki/Tropical_cyclone

[2] https://www.ready.gov/hurricanes

Featured image from [1]

West Belle Pass Barrier Headland Restoration (TE-52)

wordpress fact sheet banner TE-52-01.pngThis headland experiences some of the highest shoreline retreat rates in the nation, measuring over 100 feet a year in some locations. As the gulf encroaches upon the shoreline, sand is removed and the headland erodes. What was once a continuous shoreline spanning several miles has been reduced to less than half its original length. Furthermore, Hurricanes Katrina and Rita removed most of the emergent headland and dunes west of the pass. This headland helps provide protection to interior marshes and the Port Fourchon area; however, its continued degradation threatens the fragile bay habitat and infrastructure it once protected.

This project will reestablish the West Belle headland by rebuilding a large portion of the beach, dune, and back barrier marsh that once existed. Approximately 9,800 feet of beach and dune will be rebuilt using nearly 2.8 million cubic yards of dredged sand, and 150 acres of marsh habitat will be rebuilt using nearly 1.4 million cubic yards of dredged material. Native vegetation will be planted upon construction to help stabilize the rebuilt marsh and dune habitat.

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The project is located along the Chenier Caminada headland to the west of West Belle Pass, at the southeastern edge of Timbalier Bay in Lafourche Parish, Lousiana.

This project was approved for engineering and design in October 2006. Construction funds were approved by the Task Force in late 2009, construction began fall 2011, and construction was completed in October 2012.

This project is on Priority Project List 16.

Federal Sponsor: NOAA NMFS

Local Sponsor: CPRA