Estimated Impacts of Sea Level Rise on Florida's Lower East Coast
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Title:
Estimated Impacts of Sea Level Rise on Florida's Lower East Coast
Creator:
South Florida Water Management District
Publication Date:
Language:
English

Subjects

Subjects / Keywords:
Sea level rise ( lcsh )
Florida ( lcsh )
Shorelines ( lcsh )
Tides ( lcsh )
Coastal management ( lcsh )

Notes

Abstract:
The University of Miami Rosenstiel School of Marine and Atmospheric Sciences geologist Harold Wanless1 has estimated that sea level rise along Florida's shoreline has accelerated to a rate of 8 to 16 inches per hundred years since 1932. This is more than six times the rate recorded by earlier tide-gauge record and that estimated from geological history for the past three thousand years. However, the recent accelerated rate of sea rise is not unprecedented. Global sea level rise has been occurring at varying rates since the end of the last major ice age fifteen thousand years ago. Average sea level rates as large as 3 to 6 feet per century have lasted for periods of thousands years at a time. It is generally accepted that sea level rise is associated with global warming through several processes including the melting of mountain glaciers and thermal expansion of the ocean waters. Past global warming was likely attributed to such factors as long-term increases in solar energy output and variations of the earth's orbit around the sun. Scientific evidence suggest that in the future anthropogenic activities may also contribute in a significant matter to global warming. Regardless of the cause for the warming, the effects of sea level rise poses a formidable challenge for water resources planning for the future. The Environmental Protection Agency (EPA) is the lead federal agency for guiding coastal states on planning for sea level rise2. This role is particularly difficult because of the scale and complexity of the interaction of processes on several different scales that are involved. However, the EPA has consulted with a large group of leading experts in the fields of climate variability, oceanography and glaciology to estimate the most probable sea level rise that will likely occur in the future3. The scientists that contributed to the EPA estimates were generally experts from the National Academy of Sciences and the Intergovernmental Panel on Climate Change. The most probable global sea level rise for the year 2050 was estimated to be 0.5 feet greater than the 1995 level. This EPA estimate does not include the effects of local subsidence, erosion, compression and other tectonic instabilities that may occur at varying rates along the Florida coastlines. These additional factors may cause the relative rate of sea level rise at a particular location to be substantially different and most often at a larger rate than the global rate of sea level rise. In this regional hydrologic analysis, only the effects of the global sea level rise are being considered. The lower east coast of Florida is generally a stable coastline. In an effort to estimate the effects of expected sea level rise on south Florida's regional water management objectives of the future, the South Florida Water Management Model was modified to re-simulate the 2050 base run with the sea level boundary condition adjusted to be 0.5 feet higher than the base condition. One of the major concerns associated with sea level rise is the potential for saltwater encroachment into the coastal freshwater aquifers. The SFWMM is not designed to address the full spectrum of issues that may arise related to the potential for salt water encroachment with sea level rise scenario. However, by making some rudimentary assumptions an estimate of the potential impacts that sea level rise may have on regional water management issues such as Everglades hydroperiod restoration and impacts to regional water supply can be realized. It was with these intentions that water levels maintained within key coastal canals during dry conditions were increased by 0.5 feet. This perfunctory increase in canal maintenance levels is considered the minimal adjustment that would be required to offset the saltwater encroachment that would otherwise occur. Indeed, preliminary analysis with density-dependent groundwater models suggest that the canals may need to be maintained at even higher levels to adequately offset the projected one-half foot rise in sea level. It should also be recognized that significant infrastructure changes may also be required. ( English )

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Source Institution:
Florida International University
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