Calcasieu-Sabine Large-Scale Marsh and Hydrologic Restoration

Formerly Calcasieu Ship Channel Salinity Control Measures Project

FY 2025 Status: In Construction
Funding Source: RESTORE
FY 2025 Expenditure: $14 million
Estimated Cost: $264 million
Land Benefit: 2,000+ acres

Description: The Calcasieu-Sabine Large-Scale Marsh and Hydrologic Restoration Project (CS-0087) includes 1) large-scale marsh drainage improvements that reduce the flood stress that is currently driving marshvulnerability and 2) large-scale marsh creation and nourishment that increases elevation capital in some of the most degraded areas of the 65,000 acre Cameron Creole Watershed.

This project replaces the discontinued Calcasieu Ship Channel Salinity Control Measures Project. The former version of this project was reevaluated before the 30% design milestone was complete, as real-time data did not reflect what the models were predicting for this project and area. Through additional data collection and modeling analysis, new project goals and solution sets were considered and eventually assembled into a new restoration strategy. New analysis confirmed that saltwater intrusion was not the primary issue to consider, but rather flood stress, and as such the salinity barriers originally included in the project plans were dropped from the project. Remaining funds from the original project were then reallocated to what is now the Calcasieu-Sabine Large Scale Marsh and Hydrologic Restoration project. This project contains three main components:

• Drainage structures with backflow prevention and/or pumping systems to improve marsh drainage

• Conveyance improvements to facilitate flow of excess water to drainage structures

• Large-scale marsh creation and nourishment to increase elevation capital

Graphic by SCAPE, published in 2023 Coastal Master Plan.

Hydrologic restoration improves freshwater flows to reduce or prevent harmful saltwater intrusion. These projects control salinity levels, preventing the die-off of freshwater plants and trees. Hydrologic restoration projects can also help maintain optimal salinities needed for the success of other restoration types, such as oyster reef and marsh creation projects.

Other Hydrologic Restoration Projects

Houma Navigation Canal Lock Hydrologic Restoration | Mermentau Basin Hydrologic Restoration | Three Mile Pass Marsh Creation and Hydrologic Restoration

Graphic by SCAPE, published in 2023 Coastal Master Plan.

Marsh creation or “dredging” uses sediment from the Mississippi River, nearby water bottoms or offshore shoals to build land in shallow, open water areas, typically where land has been lost. These projects can build land fairly quickly, but will eventually fall victim to the same process that caused the land to disappear originally. This type of project can be used in conjunction with sediment diversions to trap sediment, and sediment diversions can lengthen the lifespan of marsh creation projects by providing a continual source of sediment to the new marsh surface.

Other Marsh Creation Projects

Large Scale Barataria Marsh Creation | New Orleans East Marsh Creation | Central Wetlands Marsh Creation and Diversion | Three Mile Pass Marsh Creation and Hydrologic Restoration | Delacroix Marsh Creation | East Bayou Lafourche Marsh Creation | Calcasieu Lake Marsh Creation | Belle Pass-Golden Meadow Marsh Creation | Golden Triangle Marsh Creation