USING MULTIPLE PROXIES TO DEVELOP A MID- TO LATE HOLOCENE CHRONOLOGY OF MAJOR STORMS FOR THE NORTHWEST FLORIDA COAST FOR USE IN RISK MODELING

Paleotempestology, the study of long-term regional storm history from geological evidence, has enabled us to establish a record of tropical cyclone activity during the late Holocene for NW Florida. Understanding the potential damage from storms to coastal systems and infrastructure, and predicting their future occurrence is in large part dependent on the historic record. The historic record of major storms is brief and not representative of the geologic record, encompassing only the last ~150 years. The long-term storm record, found in coastal lake sediments resulting from overwash processes, can be used to develop a better understanding of the risk of major storms to coastal regions over the next century. The risk associated with strong storms is significant as it is predicted that we may, in the near-term, experience accelerated sea-level rise and increased tropical storm intensity due to climate change.

This project is investigating the stratigraphy, sedimentology, geochemistry and geochronology of coastal lake sediments in NW Florida. The project goal is to determine the potential impact and risk of sea-level rise and projected increase in storm intensity on the northern Gulf of Mexico coastal system and on coastal infrastructure. The objective is to determine the frequency of saltwater inundation by storm surge from major storms to coastal regions of northwest Florida during the late Holocene. The storm record during the late Holocene, i.e., the past few millennia, is being quantified through analysis of coastal lake core sediments, creating a more robust estimate of the return period for major storms. Cores have been collected from coastal lakes along the northwest Florida coast to represent the historic and geologic storm record. The sediment cores are being subjected to high resolution sedimentologic and stable isotope analysis, complemented by geochronology and micropaleontology, in order to refine a method for identifying and quantifying paleostorm impacts. This information will be used to make estimates, by use of multiple models, regarding the frequency and magnitude of prehistoric storms, as well as predictions of the effect of future sea level rise, climate change, and storms on natural coastal systems and coastal infrastructure on the NW Gulf of Mexico.