Semester Award Granted

Summer 2025

Submission Date

July 2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Thesis/Dissertation Advisor [Chair]

Tiffany Roberts Briggs

Abstract

Beaches are complex, dynamic systems that provide important habitat, protection from storm impacts, support tourism, and provide numerous benefits to the economy. Coastal erosion is a natural phenomenon but is becoming a growing problem due to factors such as rising sea levels, intensity of major storms, lack of sand input from rivers, and anthropogenic activities. Florida's 825 miles of sandy beaches are experiencing accelerated erosion and adaptive management practices are needed to ensure sufficient sediment remains in the littoral system. Beach geomorphology and sedimentology research is critical to understand complex coastal processes to improve coastal management strategies for the resiliency of sandy beaches.

This dissertation addresses important research gaps for coastal morphodynamics and beach management through three research objectives presented in three separate chapters. Chapter 2 evaluates the effectiveness of proxy-based shoreline methods over a 17-year period to assess their reliability for estimating shoreline and beach volume changes. The third chapter examines the influence of beach morphology and sediment characteristics on sea turtle nesting, hatching, and emergence success across managed and non-managed beaches. The last chapter examines the impacts of extreme storm events on beach morphology and property damage, integrating socio-demographic data to inform resilience planning.

It was determined that proxy-based shoreline methods can be effective over long timescales to estimate beach volume along the south Florida coast. However, shoreline proxies underestimate beach volume at short-time scales, particularly in urbanized areas. Storm impacts resulted in complex relationships between shoreline change and volume change, influenced by barrier morphology, structure type, and coastal features like saltwater marshes. Sea turtle nesting success was found to be strongly influenced by sediment grain size, sorting, and temperature, with higher success rates occurring on mixed-management south Florida beaches comprised of cooler, finer, and more well-sorted sediments. Lastly, the novel methodology conducted to model ebb surge water channelization showed that a higher number of damaged structures occurred within proximity of the channels along a low-lying barrier island in southwest Florida. The findings from this dissertation highlight the need for site-specific, data-driven coastal management approaches to improve resilience measures for the future. As coastal populations and infrastructure continue to grow, understanding these dynamics will be critical for long-term coastal sustainability and protection.

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