From Risk to Resilience: Planning for Sea Level Rise Using High-Resolution Inundation Forecasts

Abstract

North Carolina is currently experiencing one of the highest rates of sea level rise (SLR) in the country. Since the coastal plain is very low relief, North Carolina is at particular risk to SLR and is expected to see significant increases in high-tide flooding, storm surges, saltwater intrusion, erosion, runoff, and loss of wetland habitats. Currently, there is a lack of understanding of near-term SLR impacts due to an inability to visualize projected SLR at a parcel scale. This project downscaled regional SLR models to create high-resolution inundation forecasts to provide the North Carolina Coastal Land Trust (NCCLT) with climate-driven data to inform future coastal management and conservation efforts. High-resolution depth grids were created for five focus tracts near Onslow Bay, NC, to forecast 1-3ft of SLR. These layers were compared with regional datasets to see differences in the extent and depth of inundation. The results of this study suggest the following: (1) Regional scale depth grids overestimate inundation, (2) Parcel scale outputs showed potential connectivity networks not present in the lower resolution layers, (3) The greatest difference in inundation occurs at the earliest onset of SLR, and (4) Elevation was the dominant covariate for producing updated forecasts. After synthesizing these results for NCCLT, recommendations were provided that will play a major role in shaping the future trajectory of how land is managed in the coastal plain.