The Impact Of Sea-Level Rise On Saltwater Intrusion For Coastal Aquifers In North Carolina

The coast of North Carolina has been identified as a sea-level rise hotspot because the coastline experiences higher rates of sea-level rise compared to the global mean level. These rising sea levels will subsequently lead to increased saltwater intrusion for coastal aquifers in this area. In this study, a head-controlled scenario is used to conduct an analysis of saltwater intrusion for coastal North Carolina under various sea-level rise scenarios. A head-controlled scenario assumes that as sea level rises, the hydraulic head will remain the same. This is likely to be the case because of groundwater extraction, evapotranspiration, and a lack of vertical mobility possible at these sites. The northern section of the coastline is subsiding while the southern portion remains stable, so the rates of sea-level rise vary from north to south. In all locations, the movement of the saltwater toe inland occurs at an exponential rate as sea level rises. Factors such as hydraulic conductivity, the thickness of the aquifer, and recharge influence the steepness of this saltwater intrusion curve. This study finds that if sea levels rise in excess of 1 m then some North Carolina barrier islands could lose the entirety of their freshwater lenses.