MODELING THE EFFECTS OF INCREASED SEA-LEVEL RISE AND STORMINESS ON THE NORTHWEST FLORIDA COAST

An investigation on the northern Gulf of Mexico coast has been exploring new methods for comprehensive modeling of the effects and potential risk of increased storminess and projected sea-level rise on coastal environments and infrastructure. We have applied several storm scenarios to a range of sea-level rise possibilities, ranging from a continuation of current rates to a rise of as much as 2 meters by 2100. The project has had several components, including: analyzing historic coastal change and remote sensing data; modeling future storms; analyzing the paleostorm history in coastal sediments; and modeling morphologic change.

We have developed a comprehensive database of historic changes in shorelines and barrier island morphology in the region. By combining remote sensing and survey data, we have created a unique time series of shorelines and barrier evolution over the past 150 years. This robust data set has informed our model development and enabled the creation of a conceptual model for the evolution of the Santa Rosa Island barrier, plus a purpose-built numerical model. Santa Rosa Island, sixty-five kilometers in length, is the second largest barrier on the Gulf coast. It is important as the site of significant infrastructure for Eglin Air Force Base, a large portion of the Gulf Islands National Seashore, and major seaside tourist communities.

A regional storm history has been developed for use in the modeling effort, both for historic and prehistoric time. The historic database encompasses approximately 150 years. The prehistoric record, from coastal lake sediment cores, extends over approximately four millennia. A new technique for assessing paleostorm occurrence has been developed and employed as part of the project. A new storm model incorporates the storm history to create an ensemble of future storm tracks and potential storm effects for the region.

The outcomes of this study will be used to evaluate how to make reliable predictions of the impact of future climate change on coastal infrastructure and natural coastal systems. The expected result will be to enable cost-effective mitigation and adaptation strategies to prepare for a warmer future.