Bayou Dupont Ridge Creation and Marsh Restoration (BA-48)

Problems: There is widespread historic and continued rapid land loss within the project site and surrounding areas resulting from subsidence, wind erosion, storms, and altered hydrology. Land loss data provided by the U.S. Geological Survey indicates that loss was occurring at a rate of 1.7% per year prior to construction. The natural limits of Bayou Dupont were difficult to determine in some areas because land loss was causing a merge of the bayou to adjacent water bodies. Natural tidal flow and drainage of patterns that once existed through the bayou were circumvented by the increasing area of open water.

Restoration Strategy: Project goals included: 1) creating and nourishing approximately 390 acres of marsh through sediment pipeline delivery from the Mississippi River; and   2) creating over two miles of ridge (10.5 acres of ridge habitat) along a portion of the southwestern shoreline of Bayou Dupont. Sediment from the river was hydraulically pumped to the project site to construct both the marsh and ridge features and additional material was dredged from Bayou Dupont to cover the ridge. The ridge is designed to mimic the configuration of other natural ridges within the watershed, and includes a constructed elevation conducive for the growth of native vegetation such as live oak, hackberry, and yaupon. The ridge is helping to redefine the limits of Bayou Dupont and reestablish the natural bank that once flanked the bayou and  protected adjacent marshes.

Location: This project is located within the Barataria Basin in Jefferson and Plaquemines Parishes. The marsh creation area is located along Bayou Dupont southeast of the waterbody known as the Pen.

Progress to Date: Construction began in the Fall of 2014 in conjunction with the Mississippi River Long Distance Sediment Pipeline Project (BA-43EB) and Bayou Dupont Sediment Delivery-Marsh Creation #3 (BA-164). Construction of the Bayou Dupont (BA-48) portion was completed in fall of 2015.

This project is on Priority Project List 17.

• Federal Sponsor: National Marine Fisheries Service (NOAA)
• Local Sponsor: Coastal Protection and Restoration Authority (CPRA)

Measuring Water Quality

Many wetlands of Louisiana receive their freshwater input from the Mississippi river, whose watershed drains approximately 40% of the United States’ waterways. [1] Pollutants get into the river from nonpoint sources, which are things like agricultural runoff, urban runoff from roads and sewage, or precipitation of atmospheric compounds, and thus they are spread into Louisiana’s wetlands.[2] Excessive pollutants deteriorate wetlands because they kill vital plants and animals in the ecosystem, which has feedback onto other species. Before interfering with anything in an ecosystem, we need to understand how the ecosystem functions.

Water quality plays a huge role in keeping wetlands healthy. The term “water quality” refers to several characteristics of a body of water, including salinity, nutrient concentration, turbidity, and dissolved oxygen [3]. These factors contribute to how well individuals can live and grow in the ecosystem associated with that body of water. For example, some plants and animals have a strong preference for either high or low salinity (See Salinity Stress Tolerance article), some prefer higher water levels (see Flooding and Hypoxia article), and some can live in many combinations of conditions.

Turbidity is a measure of how much suspended sediment is in the water column. Higher turbidity causes less light to penetrate to the deeper layers, so highly turbid waters often have less submerged aquatic vegetation. Turbidity can be measured with a Secchi disk or Secchi tube. Dissolved oxygen is important to aquatic plants because they still need to exchange oxygen to carry out their metabolic processes. Dissolved oxygen is measured by either luminescence sensors or electrode oxidation. [4] Many of the instruments that measure different aspects of water quality are combined into a Multiparameter Water Quality Sonde to get multiple measurements from the same sample of water. More information on specific procedures and equipment for measuring water quality can be found at https://www.fondriest.com/environmental-measurements/equipment/measuring-water-quality/.

Measuring water quality as a way of determining wetland health is important to many CWPPRA project locations. Measurements allow ecologists to determine any potential risks or threats from developing a project to the integrity of site’s established ecosystem. Fragile ecosystems can be drastically affected by constructing a project because the projects are likely to alter hydrology, salinity, and may introduce conditions that residents cannot survive. Forming a profile of water quality helps to predict the project’s positive and negative outcomes, and to predict the success and longevity of the project.

 

[1] https://www.nps.gov/miss/riverfacts.htm

[2] https://www.epa.gov/nps/basic-information-about-nonpoint-source-nps-pollution

[3] https://www.fondriest.com/environmental-measurements/parameters/water-quality/

[4] https://www.ysi.com/parameters/dissolved-oxygen

Featured image from https://phys.org/news/2017-01-technique-quickly-salt-marsh-vulnerability.html

South Lake Lery Shoreline & Marsh Restoration (BS-16)

Reasons for Restoration:

According to USGS-land loss analysis, much of the southern and western shorelines of Lake Lery and the surrounding wetlands were heavily damaged in 2005 by Hurricane Katrina. In the years following this storm, wind induced waves within the lake have begun to cause further damage to the lake’s shorelines. Currently the shorelines have become so damaged that the interior emergent marshes that are still intact are being exposed to the damaging waves. This has caused an increased loss of emergent marsh habitat. Even with the benefits of the Caernarvon Diversion Structure, without some type of restoration in this area, these marshes may not be able to fully recover.

Restoration Strategy:

This is a marsh creation and shoreline restoration project. The marsh creation aspect of the project will have a hydraulic dredge extract material from the Lake Lery water bottom and pump that material into contained marsh creation cells located south and west of the southern and western Lake Lery shorelines. This will create and/or nourish approximately 642 acres of intertidal intermediate marsh. The shoreline restoration component of the project will  have a barge-mounted dragline excavating material from the bottom of Lake Lery and placing that material along the southern and western shorelines. This restored shoreline will have a 50 foot crown width and be built to a height considered high intertidal marsh.

Progress to Date:

This project received Phase II funding in January 2012. Construction began in the spring of 2015 and is expected to be complete in the summer of 2018. All marsh creation is complete. Earthwork and vegetative plantings associated with the lake rim embankments are complete. There are ongoing discussions regarding erosion concerns along lake rim embankments.

This Project is on Project Priority List 17.

The Sponsors for this Project include:

Federal Sponsor: U.S. Fish and Wildlife Service

Local Sponsor: CPRA

 

LaBranche East Marsh Creation

Dredging of access and flotation canals for the construction
of I-10 and the Illinois Central Railroad resulted in increased
salinity and altered hydrology in the area that exacerbated
the conversion of wetland vegetation into shallow open
water bodies.

The project’s primary goal is to restore marsh that has been
converted to open water. Project implementation will result
in an increase of wildlife and fisheries habitat, acreage and
diversity, along with improving water quality. In addition,
the project will provide a storm buffer protection to I-10, the
region’s primary westward hurricane evacuation route, and
complement hurricane protection measures in the area.
Project features consist of the creation of 729 acres of marsh
and the nourishment of 202 acres of existing marsh using
dedicated dredging from Lake Pontchartrain. In addition,
10,000 linear feet of tidal creeks will be created. The marsh
creation area will have a target elevation the same as average
healthy marsh for this region. Plans are to place the dredge
material in the target area with the use of low level, noncontinuous
retention dikes along the edge of the project area
allowing overtopping of material to nourish the marsh fringe.
Vegetative plantings will be utilized in the areas deemed
most critical by the project team. Successful wetland
restoration in the immediate area (PO-17) clearly
demonstrates the suitability and stability of soil and material
availability from a sustainable borrow area.

The project features are located between Lake Pontchartrain
and I-10 in St. Charles Parish, Louisiana. It is bounded on
the west by the Fall Canal and the Bayou LaBranche
Wetland Creation Project (PO-17) and the east by a pipeline
canal.

This project is on Project Priority List (PPL) 19.

The LaBranche East Marsh Creation project sponsors include:

• Federal sponsor: Natural Resources Conservation Service
• Local sponsor: Coastal Protection and Restoration Authority

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

 

Terrebonne Bay Marsh Creation-Nourishment

Emergent marshes north of Terrebonne Bay have been
eroding as fast or faster than almost any other marshes
along coastal Louisiana. As these marshes convert to
shallow open water, the tidal prism will increase which will
in turn increase the frequency and duration of tides north
of Terrebonne Bay. This increasing tidal prism is likely
to increase the future interior marsh loss rates for those
marshes directly north of Terrebonne Bay. These marshes are
important for their habitat values as well as serving to slow
the progress of highly saline waters that threaten the lower
salinity marshes north and west of Madison Bay and in the
Lake Boudreaux basin. The
continued loss of these marshes has directly contributed to
the ongoing flooding problems of many communities along
Bayou Terrebonne including the town of Montegut.

The primary goal of this project is to fill shallow open water
areas and nourish marshes north of Terrebonne Bay/Lake
Barre thereby reducing the tidal prism north of Terrebonne
Bay and
interior land loss from tidal scouring. Specific Goals: 1)
Create 365 acres of intertidal marsh in shallow open water
and nourish 299 acres of fragmented marsh within the
project area reducing
water exchange between Terrebonne Bay and interior lakes
during tidal and small storm events. 2) Reduce erosion along
16,000 ft of the northern Terrebonne Bay shoreline.

The proposed features of this project consist of filling
approximately 365 acres of shallow open water and
nourishing approximately 299 acres of very low or
fragmented marsh with material hydraulically dredged from
Terrebonne Bay/Lake Barre. Containment dikes will be
degraded/gapped within 3 years of construction to allow
for greater tidal and estuarine organism access. This project
could be one part of a phased comprehensive plan to protect
the northern shoreline of Terrebonne Bay and the interior
marshes from further erosion and reduce the tidal prism.
The project would result in approximately 353 net acres of
marsh over the 20-year project life.

This project is located in Region 3, Terrebonne Basin,
Terrebonne Parish, along the northern shoreline of Lake
Barre/Terrebonne Bay near Bayou Terrebonne continuing
east a short distance past Bayou Chitique.

This project is on Project Priority List (PPL) 20.

The Terrebonne Bay Marsh Creation-Nourishment 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.

 

Bayou Bonfouca Marsh Creation

The marsh in this area was fairly stable prior to Hurricane
Katrina in August 2005. There was extensive damage to the
marsh along the north shore of Lake Pontchartrain and
especially localized in the marshes near Bayou Bonfouca
when the storm surge removed many acres of marsh. Marsh
loss rates should increase in the marsh surrounding these
newly created open water areas due to an increase in wind
driven fetch. Within the project area, the Lake Pontchartrain
shoreline erosion rates seem to be very low. Currently, there
is one large breach and several smaller ones in the Lake
Pontchartrain shoreline, with many more breaches seemingly
imminent. These breaches provide direct connection between
the fresher interior marshes and higher saline waters of Lake
Pontchartrain. The breaches in the bankline should be filled
before they grow to become a major exchange point causing
an increase in interior loss rates.

The primary goal of the project is to create 533 acres and
nourish 42 acres of low salinity brackish marsh in open
water areas adjacent to Bayou Bonfouca with sediment
pumped from Lake Pontchartrain.
This project would consist of placing sediment, hydraulically
dredged from Lake Pontchartrain, in open water sites to a
height of +1.2 NAVD 88 to create 458 acres and nourish
approximately 133 acres of marsh. Several historic marsh
ponds have been identified and would be restored. Tidal
creeks are also proposed to connect these ponds to facilitate
water exchange and fisheries access. Containment dikes
would be sufficiently gapped or degraded to allow for
fisheries access no later than three years post construction.

The project would result in approximately 424 net acres of
intermediate marsh over the 20-year project life.

This project is located in Region 1, Pontchartrain Basin, St.
Tammany Parish. Parts of the project are located within Big
Branch Marsh National Wildlife Refuge adjacent to Bayou
Bonfouca.

This project is on Project Priority List (PPL) 20.

The Bayou Bonfouca 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.

Kelso Bayou Marsh Creation

The most significant environmental problem affecting the
marshes in this area is deterioration and conversion to open
water. Marsh loss has and continues to occur as a result
of salt water intrusion and sediment export (erosion). The
construction of the Calcasieu Ship Channel and the Gulf
Intracoastal Waterway greatly increased the efficiency
of water exchange through Calcasieu Pass. Freshwater
retention was consequently reduced and salt water is able
to enter interior marshes and penetrate further north and
west. Project-area marshes are connected to the navigation
channels through a network of canals and bayous including
Kelso Bayou and Alkali Ditch. Unvegetated substrate
is vulnerable to increased tidal exchange and immense
quantities of organic substrate are being exported.
Recent marsh loss and scouring at the mouth of Kelso
Bayou from impacts related to Hurricanes Rita and Ike allow
increased salt water intrusion, tidal exchange, and storm
surge impacts.

The goal of this project is to restore and protect
approximately 319 acres of critically important marsh
and the numerous functions provided by those areas. The
proposed project will restore a portion of the historic
meandering channel of Kelso Bayou and provide direct
protection to Louisiana State Highway 27, the region’s only
northward hurricane evacuation route. Project features
include creating/nourishing 319 acres of marsh, 3,200 linear
feet of shoreline protection, and rock armor at the mouth of
Kelso Bayou to prevent additional tidal scour.

This project is located in Region 4, Calcasieu-Sabine Basin,
Cameron Parish. The project features are located in an area
south of the Gulf Intracoastal Waterway and just west of the
Calcasieu Ship Channel.

This project is on Project Priority List (PPL) 20.

The Kelso Bayou Marsh Creation project sponsors include:

• Federal Sponsor: Natural Resources Conservation Service
• Local Sponsor: Coastal Protection and Restoration Authority 

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

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.

 

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!

Barataria Bay Rim Marsh Creation

Historic wetland loss in the area occurs in the form of interior marsh loss and shoreline erosion along Barataria Bay. The interior loss is caused by subsidence, sediment deprivation, and construction of access and pipeline canals.

The proposed project would create approximately 251 acres and nourish approximately 266 acres of marsh using sediment dredged material from Barataria Bay. The majority of the dredged material would be fully contained. For creation of approximately  15 acres of marsh and nourishment of 34 acres in the eastern portion of the project, the dredged material would be semi-contained. Containment dikes will be degraded as necessary to reestablish hydrologic connectivity with adjacent wetlands. In case the area does no re-vegetate on its own, the maintenance cost estimate will include funds to plant 25% of the created marsh at Year 3.

BA-195 is located in Region 2, Barataria Basin, Jefferson and Plaquemines Parishes.

This project is on Priority Project List (PPL) 25 and was approved for Phase I Engineering and Design in January 2016.

Barataria Bay Rim Marsh Creation project sponsors include:

• Federal Sponsor: Natural Resources Conservation Service
• Local Sponsor: Coastal Protection and Restoration Authority

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