Approximately 65% of the beaches of west-central Florida are considered "critical erosion areas" according
to a report by the Florida Department of Environmental Protection. Under natural conditions, barrier islands shift in
response to storms, sediment supply and changes in sea-level. Man-made structures such as sea walls, jettys, and
even buildings and roads can alter the influence of these natural processes.
Consequently, some areas have seen rapid rates of beach erosion, resulting in narrow beaches that are insufficient for
recreational use or protection of upland properties. Beach erosion and loss of protective dunes has left the coast
susceptible to damage from storms and hurricanes. To address this erosion problem Congress directed the U. S.
Geological Survey's Marine and Coastal Geology Program in 1992 to initiate the West-Central Florida Coastal Studies
Project. The study area spans approximately 130 km of coast, and includes
18 barrier islands and inlets.
The problem of beach erosion is an important issue in west Florida, as the white sandy beaches attract tourists and
drive a substantial portion of the economy. In response to beach erosion, several sections of the coast have undergone
nourishment projects to restore beach widths to previous dimensions. This method of beach maintenance is expensive,
typically costing well over a million dollars for each mile of beach, and needs to be repeated as often as every four
years. While beach nourishment is becoming the most common means of addressing beach erosion, it may not provide
a cost effective long-term solution, as sand resources are limited along much of the west Florida coast.
Beaches are an important aspect of the Florida economy, attracting tourists throughout the year.
The overall goal of this project was to understand the recent geologic history of the barrier island system and
the processes that control the distribution and transport of sediment on the inner shelf. Specific objectives included:
- Understanding geologic controls on the position and development of the barrier islands and tidal inlets.
- Determining a sediment budget including sources, sinks, and pathways for sediment on the inner shelf and barrier islands.
- Determining the effects of past geologic and oceanographic events that might control the morphology and sedimentary processes of the coastal system.
Beach erosion can decrease the recreational value of beaches, as well as their ability to provide protection from storms.
The project was organized into three distinct elements:
- The Framework portion of the project included reconnaissance high-resolution seismic and side-scan sonar surveys across the entire study area, detailed side-scan sonar mosaics of selected sites to identify patterns of hard grounds and sediment cover, and coring of sediments to document historical development of the inner shelf and coastal system.
- The Processes portion of the project included field studies of the circulation and hydrography on the west-Florida shelf, numerical modeling of the shelf to explore the role of the passage of cold fronts across the shelf, and the interpretation of satellite imagery to document the complex spatial patterns of shelf processes.
- The Morphodynamics portion of the project investigated the stratigraphy and geological development of the barrier islands, and the Holocene evolution of the flood and ebb tidal deltas.