MAJOR HURRICANE LANDFALL STORM SURGE

ANALYSIS

St. John’s County, FloridaAnalysis of Historical Site Locations and Damage

Produced by David RennaGIS 4048/ Application in GIS 08/04/2010

Introduction

Hurricane Season: June 1 – Nov. 30 No major hurricane direct landfall Last direct landfall- Dora,1964 Cat.2 St. John’s County is oldest historic area in U.S. More historic sites in county than anywhere

else (4400) County economy dependent on tourism Tourism dependent on existence of historical

sites What would happen to historic sites if major

hurricane made direct landfall?

Study Area

St. John’s County, Florida

Located in North East Florida

Surrounded by the Atlantic Ocean to the East, Duval County to the North, Clay and Putnam Counties to the West and Flagler County to the South.

BackgroundSt. Augustine, Fl

America’s oldest town Founded in 1513 by Ponce de Leon

in an effort to find the exact location of the “Fountain of Youth”

Established in 1565 Spanish settlers have occupied area

for 500 years Spanish, British, French , and Indian

settlements battled over rights to these lands for 300 years

In the efforts of control of lands, hundreds of forts were built in times of war

Forts are displayed throughout St. John’s County

BackgroundSt. John’s County Historic Sites 163,000 Federal

applications for historic site designation

4400 designated sites used for this study

Historic sites are prime reason for tourism in St. John’s County.

Historic sites:1. forts2. churches3. schoolhouses 4. jails5. museums6. houses7. lighthouses

St. Augustine Cathedral

St. Augustine Lighthouse Dow Museum

Oldest Schoolhouse

BackgroundMajor Hurricane Direct Landfall

No major hurricane has ever made direct landfall in St. John’s County

Last Direct Landfall: Hurricane Dora, 1964, Category 2

Last East coast landfall of major hurricane Jeanne in 2004(S. Florida, Cat.3)

Major Hurricanes as designated by NOAA are Category 3 or greater

NOAA Saffir-Simpson Hurricane ScaleDesigned model at fas.org

Elevation Highest elevation in St. John’s

County~ 75 ft. More than 75% of historic sites in

areas considered to have low elevation and close proximity to water

Large concentrations of historic sites in St. Augustine historic downtown area in middle Eastern portion of county and in South West Region of St. John’s County

Smaller clusters of historic sites along St. John’s river, intracoastal waterway and along beaches

St. John’s County surrounded by water from St. John’s River to the West and the Atlantic ocean to the East

Downtown St. Augustine

Closer view of downtown St. Augustine

Thousands of historic structures in downtown alone

Almost all sites along waterways

Large cluster of historic structures in very small area

Flood AnalysisCategory 3 Hurricane

Percentage Flooded Lands

29.179% of total area flooded.

Historic sites within ~ 1.5-2 miles of coast all under water.

Historical sites along St. John’s river under water as arterial rivers and canals flood.

Downtown St. Augustine full engulfed.

Approximately half historic structures (over 2000) in county destroyed due to storm surge.

Flood AnalysisCategory 4 Hurricane

Percentage Flooded Lands

34.39% total area flooded Historic sites within ~ 2- 2.5

miles of coast under water All historic sites along St.

John’s river under water Additional flooding along

arterial rivers and canals moving Eastward and covering most areas of South West St. John’s County

Historic Downtown St. Augustine completely destroyed due to storm surge

Flooding moving West past US 1 and engulfing more than 70% of historic sites

Flood AnalysisCategory 5 Hurricane

Percentage Flooded Lands

47.23% total area flooded Historic sites within ~ 3-4

miles of coast under water All historic sites along St.

John’s River completely destroyed

Complete flooding of Western portion of St. John’s County

All arterial rivers and canals engulfed by rising waters

Nearly 90% of all historic sites destroyed in St. John’s County due to storm surge

Additional Wind DamageNOAA Guidelines

Category 3 Hurricane : 1. Poorly constructed frame homes destroyed by the removal of the roof

and exterior walls. 2. Unprotected windows will be broken by flying debris.3. Well-built frame homes can experience major damage due to roof

removal.

Category 4 Hurricane: 1. Poorly constructed and well-built homes can sustain complete collapse

of all walls as well as the loss of the roof structure. 2. Windborne debris damage will break most unprotected windows and

penetrate some protected windows.

Category 5 Hurricane: 1. A high percentage of frame homes will be destroyed, with total roof

failure and wall collapse. 2. Windborne debris damage will occur to nearly all unprotected windows

and many protected windows.

Results

Category 3: 1. 29% of total lands flooded 2. Historical site along coastline and along St. John’s River flooded. 3. Downtown St. Augustine under water. Nearly 50% all historical sites under

water. 4. Wind damage would also be substantial.

Category 4: 5. 34% of total lands flooded. 6. Historical sites within 2.5 miles of coast and St. John’s River flooded . 7. 70% of historical sites under water. 8. Wind damage at catastrophic levels.

Category 5:9. 47% of total lands flooded.10. Historical sites within 3.5 miles of coast line and along St. John’s River and

arterial canals completely destroyed.. 11. 90% of historical sites under water. 12. All structure completely destroyed by storm surge and wind damage.

Conclusion The importance of the historical sites to St. John’s County is

evident. The tourism due to these site is the only viable means of income

to this area. A hurricane of category 3 or higher would completely destroy

the economics of the area. All of the historical sites in St. John’s County would be destroyed. Hurricanes have traditionally remained well off our coast. It has

been a long time since St. John’s County has had a direct landfall.

Study shows the importance of readiness in the face of crisis. Due to results there is hope that local and government official

put more thought into protecting these structures. Perhaps new laws laying out formal plans to protect historical

structures in such an event are in our near future.

References Corbett, Theodore G. “Migration to a Spanish Imperial Frontier in the

Seventeenth and Eighteenth Centuries: St. Augustine” , The Hispanic American Historical Review, Volume 54. No. 3(August 1974), pp. 414-430.

Wolkomir, R. “in Search of St. Augustine”, The Smithsonian, Volume 32, No. 7 (October 2001). Pp. 114-120.

Historical Markers of Florida, Division of Historical Resources, Florida Historical Markers Program, Florida Heritiage.com, http://flheritage.com/preservation/markers/markers.cfm/ID-st.johns

NOAA Saffir-Simpson Hurricane Scale, National Oceanic and Aviation Administration, http://www.fas.org

The Saffir-Simpson Hurricane Wind Scale Summary Table, National Oceanic and Aviation Administration, http://www.nhc.noaa.gov/sshws_table.shtml

Data Sources:

St. John’s County Data Depot http://www.sjcfl.us/BCC/Land_Management/GIS/DataDepot.aspx

Florida Geographic Data Library http://www.fdgl.org/