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

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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.

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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.

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)

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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.

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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:

sponsors_1.pngFederal Sponsor: U.S. Fish and Wildlife Service

Local Sponsor: CPRA

 

Cole’s Bayou Marsh Restoration

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Project area wetlands are undergoing loss at -0.42 %/year
based on 1983 to 2011 USGS data from the extended
boundary. Wetland loss processes in this area include
subsidence/sediment deficit, interior ponding and pond
enlargement, and storm impacts resulting in rapid episodic
losses. In addition, significant interior marsh loss has
resulted from salt water intrusion and hydrologic changes
associated with increasing tidal influence. As hydrology in
this area has been modified, habitats have shifted to more of
a floatant marsh type, resulting in increased susceptibility to
tidal energy and storm damages. Habitat shifts and
hydrologic stress reduce marsh productivity, a critical
component of vertical accretion in wetlands.

The specific goals of the project are: 1) create 365 acres of
brackish marsh in recently formed shallow open water; 2)
nourish 53 acres of existing brackish marsh; and, 3) increase
freshwater and sediment inflow into interior wetlands by
improving project area hydrology.

This project aims to create 365 acres and nourish 53 acres of
brackish marsh via dedicated dredging with borrow from
nearby Vermilion Bay. Although Vermilion Bay is not
considered an “external” source of material, significant
sediment inflows into this area may result in some borrow
area infilling. Half of the marsh creation acres would be
planted. The project will encourage additional freshwater
nutrient and sediment inflow from Freshwater Bayou Canal
by dredging a portion of Cole’s Bayou along with the
installation of a series of culverts throughout the project
area.

The culverts located along the northern project boundary are
envisioned to allow the ingress of sediment, water, and
fisheries organisms into the semi-impounded project area,
but avoid backflow of water and potential loss of interior
marsh sediment (i.e., north to south flow only). The culverts
located along the southern project boundary are envisioned
to allow water to drain out of the marsh.

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This project is located in Region 3, Teche/Vermilion Basin,
Vermilion Parish, east of Freshwater Bayou Canal.

This project is on Priority Project List (PPL) 21.

The Cole’s Bayou Marsh Restoration sponsors include:

 

The People of Louisiana’s Coastal Wetlands

The Coastal Wetlands Planning, Protection and Restoration Act leads the fight against Louisiana’s disappearing coast. The native people of coastal Louisiana are greatly worried about losing their homes, sources of livelihood, and culture if the lands they live on continue to disappear. Saltwater intrusion, marshes becoming open water, and the disappearance of barrier islands and protective wetlands are a few of the challenges facing coastal communities. For centuries, marshes have served as home to numerous people: American Indian tribes, Vietnamese, Croatian Americans, and other groups. All of these coastal residents are familiar with the hardship of living in an area frequented by natural disasters. Most coastal residents have chosen to stay on their lands to defend and protect the ecosystem despite the extreme risks. Without the hard work and effort of diligent landowners and organizations like CWPPRA, coastal Louisiana would be vanishing at a much faster rate.

You can read Watermarks #48 People of the Coastal Wetlands to learn more about this topic.

Wetlands and Waterfowl

At this time of year in Louisiana, you are sure to see early morning waterfowl hunters dressed in their best camouflage. Louisiana sits on the Mississippi Flyway, North America’s most heavily-used migration corridor for waterfowl. Louisiana’s coastal wetlands provide habitat for more than five million migratory waterfowl, approximately half of the wintering duck population of the Mississippi Flyway. The coastal marshes of Louisiana provide habitat to mottled ducks, wood ducks, redheads, and pintails, just to name a few species. These waterfowl species can be spotted in coastal marshes, flooded timbers, flooded grain fields, and other wetland areas. Grab your waders, shot gun, and a duck call, and take advantage of Louisiana’s Sportsman’s Paradise.

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It is critical to protect the coastal marshes and wetlands within the state for Louisiana to remain the front runner for waterfowl hunting. CWPPRA projects are aimed at protecting and restoring Louisiana’s coastal wetlands, ensuring that wildlife and the people who hunt them have the habitat they need.

LaBranche East Marsh Creation

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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.

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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:

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

 

Terrebonne Bay Marsh Creation-Nourishment

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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.

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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:

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

 

Bayou Bonfouca Marsh Creation

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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.

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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:

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

Kelso Bayou Marsh Creation

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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.

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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:

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