At a Glance

CSE conducted a 4,742-acre offshore investigation to evaluate sand resources for future nourishment along Hatteras Island. Integrated hydrographic and geophysical surveying mapped seafloor conditions, subsurface geology, and potential environmental and cultural resources, supporting Dare County’s long-term sediment management strategy.

Year 2026
Location Hatteras Island, NC
Client Dare County, NC
Scope 4,742 acres

Finding Future Sand Beyond State Waters

Recurring nourishment at Buxton requires a reliable supply of beach-compatible sand, but previous resources were identified largely on a project-by-project basis. Expanding the search into federal waters required detailed mapping of offshore conditions, along with BOEM coordination and consideration of environmental and submerged cultural resources. The challenge was to efficiently investigate a large offshore area and generate defensible data to guide future sediment sampling and borrow-area development.

Challenge

Mapping the Seafloor from Multiple Perspectives

CSE conducted an integrated geophysical investigation using multibeam sonar, sub-bottom profiling, sidescan sonar, and magnetometry. Survey lines spaced at 100 feet, combined with precise GNSS/INS positioning, mapped bathymetry and seafloor features, characterized subsurface sediment layers, and identified potential cultural resources and other features requiring avoidance.

Approach

Building the Foundation for Future Nourishment

The 4,742-acre investigation created a detailed picture of offshore bathymetry, subsurface geology, and potential constraints within a prospective sand-resource area. The resulting data provide the technical foundation for targeting future sediment sampling, evaluating beach-compatible material, and advancing federal coordination for future borrow-area development. By investigating offshore resources at a larger scale, CSE is helping Dare County plan beyond a single nourishment cycle and build a more efficient, long-term sediment management strategy for Buxton.

Impact
Challenge
Approach
Impact

"Understanding what lies beneath the seafloor is the first step toward securing future sand resources. Detailed hydrographic and geophysical data allow us to target the most promising areas and plan nourishment with greater confidence."

Patrick Barrineau

Patrick Barrineau

CSE/Project Manager

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