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Project: Bayou Shoreline Protection & Marsh Creation
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Where:
Vermilion Parish, Louisiana
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Overview
The Freshwater Bayou Canal provides major shipping access from the Gulf of Mexico to Louisiana’s Intracoastal Waterway. Wakes from vessels traveling the canal have eroded the shoreline, exposing interior marshes to increased saltwater intrusion, wake impact and tidal scour, which, in turn, have depleted organic marsh soils and destroyed vegetation. GeoEngineers provided a comprehensive geotechnical investigation and engineering recommendations to help protect the canal shoreline and create approximately 100 acres of marsh adjacent to the Freshwater Bayou. |
Approach
- Explored soil conditions in the canal and marsh area using a pontoon mounted drilling rig and marsh buggy.
- Designed a solution involving rock dikes at designated areas along the canal to protect the shoreline from wake and tidal action.
- Developed design solutions to maximize the height and weight of rock dikes in areas of soft clay soil.
- Designed earth dikes to create marsh ponds adjacent to the Freshwater Bayou Canal and recommended pumping fill from the canal into the interior marsh ponds to help create needed habitats.
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Results
- The rock dikes range in height from three feet in the softest soil areas to seven feet for the strongest soil. The protective dikes are designed to dissipate wave energy thereby reducing shoreline erosion.
- Recreated approximately 100 acres of marsh near Freshwater Bayou, enabling the surrounding basin to function as a freshwater marsh habitat.
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Facts
- Louisiana has lost more than 1.2 million acres of coastal wetlands since the 1930s and is still losing as much as 25 square miles a year according to the Coastal Protection and Restoration Authority of Louisiana (CPRA). During a one-month stretch in the late summer of 2005, the CPRA says Hurricanes Katrina and Rita washed away more than 200 square miles of precious coastal wetlands.
- The total cost of the Freshwater Bayou Shoreline Protection and Marsh Creation project reached $17.6 million.
- GeoEngineers completed its portion of the project for the Louisiana Department of Natural Resources on time and on budget.
- Lead GeoEngineers office: Baton Rouge
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