DRG Reduces Erosion Risks Through Inlet Relocation In Wrightsville Beach, NC

Wrightsville Beach

Davey Resource Group experts used their regulatory knowledge and environmental expertise to assist with the relocation of the Mason Inlet to mitigate erosion risks for nearby residential and commercial properties and infrastructure.

Project Narrative:

On behalf of New Hanover County (North Carolina), Davey Resource Group (DRG) served as the lead environmental consultant for environmental site evaluations and documentation for the proposed relocation of Mason Inlet at the north end of Wrightsville Beach, North Carolina. As a result of the accelerated migration of the inlet to the south, residential and commercial properties and infrastructure of the north end of Wrightsville Beach became highly susceptible to erosion. In response, a plan was developed to relocate the inlet 3,000 ft north toward Figure Eight Island while concurrently infilling the former inlet throat. The proposed project included the potential disturbance to a range of sensitive coastal habitats, including Essential Fish Habitat (EFH) and foraging/nesting habitat of colonial waterbirds and shorebirds (e.g. the endangered piping plover). As a result, the proposed action required a high level of regulatory and stakeholder coordination.

DRG worked closely with the Regulatory Branch of the U.S. Army Corps of Engineers (Corps), Wilmington District throughout project scoping and permitting. Biologists and permit specialists with DRG prepared the Environmental Assessment (EA) for the Corps to be able to document compliance with the National Environmental Policy Act (NEPA). To adequately document potential adverse effects to natural resources, DRG staff mapped various habitat types and conducted baseline environmental monitoring within and adjacent to the project area. In conformance with Section 404(b)1 federal guidelines, DRG and the project engineer conducted alternatives analyses and received concurrence that the proposed action was the least environmentally damaging, practicable alternative (LEDPA).

Creating A Successful Relocation Project

As a result of the habitat inventories, impact analyses, and appropriate design modifications, Section 404/401 and Coastal Zone Management Act permits were obtained for the preferred project alternative. In addition, DRG developed a tidal salt marsh mitigation plan designed to offset adverse impacts to the marsh habitat associated with the relocation of the inlet. A former Corps dredge disposal island located adjacent to the Atlantic Intracoastal Waterway (AIWW) was identified for tidal wetland restoration. DRG worked with both the Regulatory and Navigation Branches of the Corps Wilmington District as part of the mitigation plan development. The tidal salt marsh restoration project successfully re-established high marsh, low marsh, and primary nursery habitats. DRG was responsible for mitigation site feasibility, design, construction management, site planting, and post-construction monitoring. Based upon geotechnical investigations of the material, the excavated sand was able to be beneficially used for beach nourishment on Figure Eight Island. After documenting successful hydrologic restoration of the coastal marsh area, DRG was able to receive concurrence from the Corps to discontinue hydrologic monitoring of the site (resulting in significant cost savings to the County). DRG continues to perform long-term biological monitoring of the Mason Creek marsh system and the Waterbird Management Area (WMA) on behalf of New Hanover County and assists with environmental documentation to allow for navigation maintenance of Mason Creek and the adjacent Corps-maintained AIWW.

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