Bayou Bonfouca Marsh Creation

wordpress fact sheet banner-01

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.

po104_20140611.jpg

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.

New Orleans Landbridge Shoreline Stabilization & Marsh Creation

banner-01

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.

map

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:

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