SIMULATING MARINE AND GROUNDWATER INUNDATION ON A BARRIER ISLAND SETTING UNDER CHANGING SEA-LEVEL RISE SCENARIOS

Numerical modeling and geospatial techniques were used to assess the extent of groundwater and marine inundation on Bogue Banks barrier island (North Carolina) in response to future sea-level rise scenarios (0.2-1.4 m). Hydrogeologic data and groundwater levels collected from 29 wells across the island were used to build and calibrate a numerical model of the surficial aquifer on the island. The calibrated model was used to simulate the impact of sea-level rise on the water table under steady-state conditions. Geospatial techniques were then used to estimate the proportion of land lost to groundwater and/or marine inundation under the projected sea-level scenarios. Results reveal that marine and groundwater inundation would have comparable impacts, with between 7 and 22% of the land being lost to water under sea-level rise scenarios of ≤1.2 m. At extreme sea-level rise scenarios (1.4 m), the effects of groundwater inundation were far much greater than those of marine inundation (with land losses of 28% for marine inundation and 40% for groundwater inundation). As a consequence, groundwater inundation may therefore play an important role in management issues related to how climate change and sea-level rise may impact water resources in coastal communities.