BARRIER ISLAND EROSION AND BEACH NOURISHMENT – THE DIFFICULT ART OF FINDING SCIENCE AND SOCIETAL OVERLAP

Barrier island beaches encompass the largest tourism destinations and high-valued real estate in the Nation. However they may be the least static landforms in the world, and along the southeast U.S. are shaped by sea-level fluxes, sediment supply, and storm activity superimposed on inherent geologic frameworks. Accordingly, maintaining infrastructure to sustain/grow tourism, real estate economies, and local governments present unique challenges. In N.C., existing law/regulations forbid the use of hard structures for erosion control, leaving communities to choose between beach nourishment or retreat, with nourishment considered the most favored option. The resulting beach management decisions predicated upon various stakeholder input often result in a clash between geologic sciences and societal demands.

Bogue Banks is a 25-mile long south-facing island and is the only developed reach along the centermost 100 of the State’s total 325 miles of shoreline. As such, it is an economic focal point for the region populated by 5 different political subdivisions and a State Park. The island possesses high widths (~800 to ~4,000 ft. ) and elevations (15 to 25 ft. above mean sea level) as evidenced by dense vegetation and a rich maritime forest. The State’s erosion rate for the island is “low” (< 2.5 or 2 ft./yr). However sea-level rise in general, and historical sediment removal practices associated with the Morehead City Harbor navigation project and impacts associated with 5 landfall tropical cyclones from 1996 – 99 in particular left beaches and infrastructure compromised.

Implementing a dense profiling network, local government governance, and a multi-faceted plan resulted in several nourishment projects that delivered 10 million cubic yards of sand at a State, federal, and local cost of $80 million. The projects included a diversity of voter-approved bond referendum, federal cost-sharing authorities, and FEMA reimbursements. While this incremental approach served the area well in the 2000s, local leadership is pursuing legal action against federal dredging practices and is developing a comprehensive 30-year Master Plan. The latter takes the latest geologic/engineering information, logistical lessons learned, and a new interlocal agreement to reach common ground between science and political constituencies.