MODELING NEAR-FUTURE RESPONSE TO SEA LEVEL AND CLIMATE CHANGE ON THE NORTHWEST FLORIDA COAST

Near-future scenarios of sea-level and storminess project a significant acceleration in the rate of sea-level rise and an increase in storm intensity. Several recent model projections for sea-level change over the next century predict rates of sea-level rise greater than any experienced during the Holocene. A range of possible near-future scenarios is being applied in a modeling and field investigation of the northwest Florida coast. We are examining the potential risk to coastal systems and infrastructure under conditions of both sea level and storminess that differ considerably from those of the past century. The project focuses on the Eglin Air Force Base region of the central panhandle coast, and a major barrier island, Santa Rosa Island. We are employing remote-sensing and survey data to examine barrier island morphologic change over historic time, and as input to process-response models of future barrier morphologic change. We have developed a storm history for the region, for both the historic and pre-historic period. Coastal lake sediment cores are being used to extend the record of major storm impacts back into the past several millennia. A storm model is incorporating this storm history to create an ensemble of realistic storm tracks and projections of future storm occurrence for the region. Results of the modeling effort includes an enhanced coastal model for the response of shorelines, dunes, barrier island, and salt marshes to sea-level rise This model is simple and computationally efficient, so that each scenario represents hundreds of simulations of the next 100 years in a Monte Carlo procedure. Results are presented statistically, including evaluations of variability and uncertainty. The output from this study will be used in developing methodologies for mitigating the effects of future sea-level rise and storm increase on coastal systems and infrastructure on this and similar coastal environments.