Moffatt & Nichol – Rising Above the Tides: Graveline Bay Marsh Restoration Project

Partners for Environmental Progress recently awarded Moffatt & Nichol a 2024 Environmental Stewardship Award. In recent years, the northern Gulf of Mexico’s barrier islands, particularly Dauphin Island, have faced severe environmental challenges. Hurricanes have left their mark, causing island lowering, breaches, and a significant loss of landforms that play crucial roles in the region’s ecological balance.

One such affected area is Graveline Bay, where 75 acres of marshland have been lost over the past century. This alarming rate of loss threatens the estuarine ecosystems essential for wildlife and the local community. In response to these challenges, the Graveline Bay Marsh Restoration Project was initiated to restore and enhance the remaining 37 acres of marshland. Funded by the National Fish and Wildlife Foundation Gulf Environmental Benefit Fund (NFWF GEBF), the project aims to bring back the bay’s ecological health and resilience.

A Vision for Restoration

The primary goal of the Graveline Bay Marsh Restoration Project is to restore the ecological functions and services of the marshes, compensating for the damage caused by the Deepwater Horizon oil spill. The project focuses on creating intertidal and high marsh habitats through innovative techniques, including constructing marsh mounds. These mounds are designed to increase the island’s resilience to storm events and provide critical habitats for various species.

Key Objectives and Achievements

The project’s objectives included maximizing the linear footage of heterogeneous marsh and fringe (edge) habitat and increasing the area of subaerial marsh habitat. To achieve these goals, the team constructed 55 intertidal marsh mounds using 300,000 cubic yards of material. Notably, the project avoided using breakwaters to attenuate wave activity, relying instead on natural materials like sand and recycled oyster shells. This approach not only preserved the natural habitat but also provided cost savings.

Specific Achievements:

• Constructed 55 marsh mounds.
• Created 30,000 linear feet of critical marsh fringe habitat.
• Restored 60 acres of submerged and emergent estuarine back-barrier island habitat.
• Observed 7 bird species utilizing the constructed habitat for 1,600 nests.
• Planted 75,850 vegetative plants.
• Enhanced nesting for diamondback terrapins and birds with 600 cubic yards of recycled oyster shells.

Innovative Design and Cost Savings

The innovative design of the marsh mounds played a crucial role in the project’s success. By focusing on constructing larger, higher mounds to protect smaller, lower-elevation mounds, the project created a robust system that minimized the need for rock breakwaters. This “soft” ecosystem restoration approach led to significant cost savings, with the project costing around $7 per cubic yard compared to a similar project costing $25 per cubic yard. This saved the funders approximately $2 million.

“The environment of Graveline Bay provided a unique opportunity to focus 100% of our construction funding on habitat restoration. We maximized ecological productivity over the project life by focusing on marsh edge habitat and constructing a sacrificial row of marsh mounds in lieu of traditional shoreline protection measures,” says Nick Cox, Engineer of Record at Moffatt & Nichol Coastal Engineer.

Collaborative Efforts and Long-term Impact

The project involved agencies, municipalities, the public, regulatory bodies, and marine contractors. The NFWF GEBF provided funding, with the Alabama Department of Conservation and Natural Resources overseeing the project. The Town of Dauphin Island acted as the project owner, and the Dauphin Island Sea Lab is conducting three years of monitoring.

“This first-of-its-kind project in Alabama takes an innovative approach to maximizing the ecological production of Graveline Bay. By designing marsh mounds in lieu of a continuous marsh platform, the area of fringe habitat that provides refuge to fish, crab, and shrimp species was expanded. Additionally, the restored marsh serves as a natural first line of defense against storm surge and rising sea levels to the community of Dauphin Island,” notes Eric Nichol, President and CEO of Moffatt & Nichol.

A Model for Future Projects

The Graveline Bay Marsh Restoration Project serves as a pilot project, offering valuable insights for future restoration efforts. Its contractual approach to environmental construction can benefit both engineers and contractors, minimizing risks and maximizing ecological benefits. The project’s success in achieving cost savings while enhancing environmental outcomes demonstrates the potential of “soft” ecosystem restoration measures.

“The restored project site provides a nursery to several species that reside and migrate through Dauphin Island. The intertidal and high marsh habitat have provided areas for at least 7 different bird species to utilize as nesting habitat. Over 1,600 shore bird nests have been observed at the site in the year it has been constructed. Additionally, 600 cubic yards of recycled oyster shell was placed at the site to enhance nesting habitat for diamondback terrapin. As the site continues to be established, both aquatic and bird species will be able to depend on the marsh in Graveline Bay to provide the ecosystem services that these species require to thrive,” says Meg Goecker, Project Manager and Senior Coastal Scientist at Moffatt & Nichol.

Conclusion

The Graveline Bay Marsh Restoration Project is a testament to the power of innovative design and collaborative effort in environmental restoration. By leveraging natural and nature-based features, the project has restored critical habitats, enhanced resilience to storm events, and provided a model for future restoration efforts.

“The Graveline Bay Marsh Restoration Project restored back-barrier marsh habitat on Dauphin Island that has been lost over time. This project will rebuild natural resilience to Dauphin Island by restoring ecosystem processes and functions, while simultaneously reducing erosion and providing protection for the leeward areas,” says Jeff Collier, Mayor of the Town of Dauphin Island.

Through innovative approaches and collaborative efforts, we can restore and protect our precious ecosystems for generations to come.