Restoration Project Types

Freshwater Diversion. This controlled diversion uses gates or siphons to regulate the volume of water flow. Freshwater is channeled form a nearby river or waterbody into surrounding wetlands. This infusion of water, sediment, and nutrients helps slow saltwater intrusion and promotes the growth of a new marsh. An example of a freshwater diversion is the Davis Pond Freshwater Diversion (BA-01).

Davis Pond Freshwater Diversion (BA-01)

Outfall Management. A variety of techniques are used to regulate the flow of freshwater diversions to ensure that water and sediment reach needed areas. These techniques maximize the benefits of freshwater diversions and can involve regulating water levels and direction of water flow to increase the dispersion and retention time of fresh water, nutrients, and sediment in the marsh. The water flow may be regulated by a combination of gates, locks, weirs, canal plugs, and gaps cut in artificial levee banks. One example is the Caernarvon Diversion Outfall Management (BS-03a).

Caernarvon Diversion Outfall Management (BS-03a) Structure

Sediment Diversions. This uncontrolled diversion promotes the creation of new marsh in place of open-water areas. A gap (called a crevasse) is cut into a river levee, allowing river water and sediment to flow into nearby wetlands and mimic natural land-building processes.  An example of an uncontrolled river diversion is the West Bay Sediment Diversion (MR-03).

West Bay Sediment Diversion (MR-03)

Dredged Material/Marsh Creation. Dredged material/marsh creation projects involve the beneficial use of sediment that is frequently dredged for maintenance of navigation channels and access canals, or material may be dredged specifically for marsh creation. The material is placed in a deteriorated wetland at specific elevations so that desired marsh plants will colonize and grow to form new marsh. The dredged material/marsh creation technique was used in the Bayou LaBranche Wetland Creation Project (PO-17).

Bayou LaBranche Wetland Creation (PO-17)

Shoreline Protection. Shoreline protection projects involve various techniques designed to decrease or halt shoreline erosion. Some techniques, such as rock berms, are applied directly to the eroding shoreline; other, techniques, such as segmented breakwaters and wave-damping fences, are placed in the adjacent open water in order to decrease a wave’s energy before it hits the shoreline and to promote the buildup of sediment. Examples of shoreline protection include Bayou Chevee Shoreline Protection (PO-22) and Cameron Prairie National Wildlife Refuge Shoreline Protection (ME-09).

Cameron Prairie Refuge Protection (ME-09) project rock breakwater

Sediment and Nutrient Trapping. Sediment and nutrient trapping projects create new land and protect nearby marshes by means of structures that are designed to slow water flow and promote the buildup of sediment. Examples include brush fences, such as Christmas tree brush fences, which work best in low-energy environments, and shallow bay terraces, which involve dredging sediment from a shallow bay and placing it above the water level in the form of land ridges. A restoration project that utilized sediment and nutrient trapping was the Little Vermilion Bay Sediment Trapping (TV-12).

Little Vermilion Bay Sediment Trapping (TV-12)

Hydrologic Restoration. These projects involve reverting human-altered drainage patterns toward more natural drainage patterns in an attempt to address problems associated with artificially altered hydrology. On a large scale, this technique may involve locks or gates on major navigation channels; on a smaller scale, it may involve blocking dredged canals or cutting gaps in levee banks that were created by canal dredging. The Hopedale Hydrologic Restoration (PO-24) project is an example of this type of restoration strategy.

Hopedale Hydrologic Restoration (PO-24)

Marsh Management. This type of project has historically been used to manage land for waterfowl and furbearers. This wetland restoration technique involves controlling the water level and/or salinity in an impounded marsh area. A variety of structures can be employed with different capacities of altering water levels and salinities in order to achieve the regrowth of desired vegetation and wildlife habitat. An example is the East Mud Lake Marsh Management (CS-20) Project.

East Mud Lake Marsh Management (CS-20)

Barrier Island Restoration. Barrier island restoration projects are designed specifically to protect and restore the features unique to Louisiana’s barrier island chains. This type of project may incorporate a variety of restoration techniques, such as the placement of dredged material to increase island height and width, the placement of structures to protect the island from erosive forces, and the placement of sand-trapping fences, which are used in conjunction with vegetation plantings, to build and stabilize sand dunes on barrier island beaches. An example of a barrier island restoration project is the East/West Grand Terre Islands Restoration (BA-30).

East/West Grand Terre Islands Restoration (BA-30)

Vegetation Planting. Vegetation planting projects are used both alone and in conjunction with shoreline protection, barrier island restoration, marsh creation, and sediment and nutrient trapping restoration techniques. This technique involves the use of flood-tolerant marsh plants that will hold sediments together and stabilize the soil with their roots as they become established in a new area. An example of this restoration strategy is the Chandeleur Islands Marsh Restoration (PO-27).

Chandeleur Islands Marsh Restoration (PO-27)

Demonstration Projects. Demonstration projects are small-scale, short-term projects that allow CRD and others to evaluate new, innovative restoration techniques. These projects will ultimately provide useful information for the design of future large-scale projects. One innovative demonstration project is the Lake Salvador Shore Protection Demonstration (BA-15) project.

Lake Salvador Shore Protection Demonstration (BA-15) Rock Berm Structure

Louisiana’s Vanishing Wetlands
The Breaux Act