Bayou Grand Liard Ridge and Marsh Project

NOAA Fisheries is the federal sponsor for a $42 million dollar coastal restoration effort currently under construction and funded through the Coastal Wetlands Protection, Planning, and Restoration Act (CWPPRA) program.  CWPPRA is federal legislation designed to identify, prepare, and fund construction of coastal wetlands restoration projects to address issues related to Louisiana’s vanishing coastal wetlands *(football size field per hour). It is one of two ridge and marsh habitat restoration projects sponsored by NOAA completing construction this year. Both projects are co-sponsored with state partner Coastal Protection Restoration Authority.
*A football field is 1.3 acres. The photo below features 180 acres of coastal wetlands, or ~138 football fields.

Figure 1 - Aerial view of marsh and ridge construction in April 2015, photo courtesy of Weeks Marine, Inc.

 

The Bayou Grand Liard Ridge and Marsh project is intended to restore both structural and habitat functions of the bayou and its associated flanking marshes located west of the Mississippi River in Plaquemines Parish, Louisiana. Historically, the river deposited sediment along the bayou bank line and marshes of this area.  Over the last several decades the construction of levees, exploration of oil and gas, and impacts from hurricanes have significantly altered the system, degrading the wetlands to open water. Past land loss projections indicate that the remaining bayou bank wetlands will be completely converted to open water by 2050 without restoration.

Figure 2 - The red dot to the bottom right of the Louisiana map depicts the regional location of the project on the eastern side of the coast.

 

Figure 3 - 100 years of wetland change in Coastal Louisiana, map courtesy USGS.

 

The project design includes the creation of 400 acres of marsh with material excavated from the Gulf of Mexico by hydraulic dredging.  The project also includes the restoration of a 3-mile section of east bank bayou coastal ridge habitat to be planted with woody vegetation.  The restoration of these structural features act as a flood control buffer against hurricanes and storms and contribute to coastal resiliency.  The restoration of wetland habitat replenishes breeding grounds and nurseries for aquatic life which contributes to sustaining fisheries (i.e., red drum, black drum, gulf menhaden, spotted seatrout, American oyster, white and brown shrimp, southern flounder, and blue crab).  It is also important habitat for some endangered or threatened species (i.e., brown pelican, piping plover, West Indian manatee, and all five species of sea turtles). The restoration of the coastal maritime ridge provides wildlife habitat for waterfowl, coastal resident, and neotropical migratory birds. Project construction is being performed by Weeks Marine, Inc., and is scheduled to be complete in July 2015.

Figure 4 - C. R. McCASKILL dredge excavating material from Gulf of Mexico for marsh restoration, photo courtesy of Weeks Marine, Inc.

 

ABC’s of Habitat

Wetland - a wetland is defined as land or areas (such as marshes, estuaries or swamps) that are covered often intermittently with shallow water or have soil saturated with moisture. Different kinds of wetland arise due to a few key factors, principally water levels, fertility, natural disturbance and salinity.

Bayou - a bayou is a body of water typically found in flat, low-lying areas, and can refer either to an extremely slow-moving stream or river (often with a poorly defined shoreline), or to a marshy lake or wetland.

Levee - a levee is an elongated naturally occurring ridge or artificially constructed fill or wall, which regulates water levels. It is usually earthen and often parallel to the course of a river in its floodplain or along low-lying coastlines.

Ridge - natural ridges are the result of formations by the repeated overbank flood sedimentation of rivers in southeast Louisiana. Principally, the rivers involved in creating these natural levees are past distributaries of the Mississippi River.

Wildlife impacted by this restoration project

Figure 5 - Coastal bird Ibis feeding near marsh creation site, photo courtesy of AECOM.

 

Figure 6 - Seagulls flying over Bayou Grand Liard, photo courtesy of AECOM.

 

Figure 7 - Brown pelican wading near ridge construction, photo courtesy of AECOM.