PREDICTED HABITAT INUNDATION ON MASONBORO ISLAND DUE TO SEA-LEVEL RISE

Masonboro Island is an 8-mile long barrier island in southeastern North Carolina that has been heavily studied for erosion, deposition, and migrating shoreline for years. These studies have concluded that the island is slowly retreating landward, as occurs naturally with eustatic sea-level rise, but increased sea-level rise due to anthropogenic climate change, combined with the continual maintenance of the Intracoastal Waterway through dredging, is causing the island to slowly disappear.

The southern end of the island has been eroding faster than the rest of the island. This project determined the amount of land lost in this area to predicted sea level rise from the spoil islands and the beach over the next 140 years; and compared digitized coastlines from an eight-year span to portray how these changes have already occurred.

Coastal land and barrier islands are most vulnerable to inundation and submergence, but how much land will be lost depends primarily on elevation, as well as erosion, deposition, migration, and other dynamic factors. Using a digital elevation model of the area generated by LiDAR data, predicted rises of 0.5, 1.0, and 1.5 feet were calculated in ArcMap using spatial analyst tools based on calculated rates of sea-level rise for the North Carolina coast from previous research studies. If the southern end of Masonboro Island did not change at all from 2006, rising sea level would submerge a total of 5,333,400 ft² (62%) by the year 2146, not including marshland lost. Given the dynamic nature of barrier islands, this may be a gross underestimate of land lost over this period of time; and rising sea-level’s synergistic effects on barrier island processes may have dramatic implications for future preservation of the island.