Evaluation of Sea Level Rise for FEMA Flood Insurance Studies: Magnitude and Time-Frames of Relevance

At present, evaluation of sea level rise is not a required component of Federal Emergency Management Agency (FEMA) National Flood Insurance Program (NFIP) Flood Insurance studies (FIS). Present day rates of sea-level rise are not insignificant, and the potential exists for these rates to accelerate. This study investigates whether current and anticipated rates of sea level rise are relevant to the NFIP considering current product life-cycles. Observed rates of sea-level rise and anticipated increases in water levels at four sites were compared to the statistically determined 1% annual chance stillwater elevation. The effect of sea level rise on mapped base flood elevations was evaluated using the Coastal Hazard Analysis Program. Results show that although increases in water elevations due to sea-level rise are not significant compared to the 1% annual chance stillwater, changes in base flood elevation zone breaks can occur over time-frames relevant to NFIP products.