The document summarizes a study analyzing the potential damage to historic sites in St. John's County, Florida from storm surge caused by Category 3, 4, or 5 hurricanes. The study found that a Category 3 hurricane would flood 29% of the county, destroying over half of the historic structures. A Category 4 hurricane would flood 34% of the county and damage over 70% of historic sites. A Category 5 hurricane could flood 47% of the county and destroy around 90% of the historic sites due to catastrophic storm surge and wind damage. The document concludes that a major hurricane would devastate the local economy and tourism industry by destroying the historic sites that St. John's County is dependent upon.

1. David Renna
GIS 4048/Apps. In GIS
Project Summary
08/05/2010
Major Hurricane Storm Surge Analysis: St. John’s County, Fl
Analysis of Historical Sites Location and Damage
Slide1: Title Page
My name is David Renna. This is a study of St. John’s County, historic sites and analysis of flood damage
due to storm surge in the event of a major hurricane to these historical sites.
Slide 2: Introduction
Hurricane season is upon us. We are going into the prime part of the hurricane season for the
formation of catastrophic hurricanes (Cat.3-5). This is a major concern for everyone who lives along the
Atlantic and Gulf Coasts. Every year, during the months from June to November, coastal residences
become very aware of the threat of a landfall from a major hurricane. This is especially true for the
residence of St. John’s County, Fl. It has been many years since a direct impact from any hurricane, much
less a major hurricane, has hit this area. The last direct hit was Hurricane Dora in 1964. It seems as
though this area is due for a catastrophic hurricane in the near future.
That being said, one must take into account the area in question. St. John’s County is probably
one of the important regions in the country in the preservation of historical archeological sites. The
county boasts one of the most impressive historical preservation collections of anywhere in the U.S. It is
a part of everyday life. There are tours of the most important sites done daily. The tourism of St. John’s
County is completely dependent on the areas archaeological preservation and the preservation of
historically important sites. So the question to be asked is “What would happen to the historical
preserved areas of St. John’s County if the area were to take a direct hit from a Cat 3, Cat 4, or Cat 5
hurricane?”
Slide 3: Study Area
St. John’s County, Florida is located in Northeast Florida. It is in the heart of the First Coast. It is
surrounded by waters from the Atlantic Ocean to the East and the St. John’s River to the West. Duval
County is to the North. While both Clay and Putnam counties are to the west on the other side of the St.
John’s River. Flagler County is to the South.
Slide 4: Background
The migration of Spanish Colonial settlers to St. Augustine was the earliest migration of Eastern
European settlers to the North American continent. In 1513, Ponce de Leon arrived on these shores in
search of the “Fountain of Youth”. (Wolkomir, R. 2001) Over half a century later a colony of French

2. Huguenots landed very near the same portion of the coast. This settlement of Protestants ignited an
entrenched battle between the Protestants and the Spanish. Pedro Menendez de Avilo arrived here in
1565 and began to eliminate to Protestants with little or no resistance establishing St. Augustine as
America’s first town. During this time, many of the Forts that the area is known for were constructed.
In the three hundred year history of St. Augustine and of St. John’s County, there has been
occupation by British, Spanish, French, and Indian settlements. Not to mention the ever growing
population of Menorcans from off the coast of Spain. In 1821 Florida was established as a state by the
American government. Along the way there have been many battles for control of the area. These
battles have allowed for the construction of hundreds of forts of different styles and time periods.
Slide 5: Background
Forts are not the only preserved sites within St. John’s County. There has also been a push to
preserve the historic buildings and areas of St. John’s County. These included churches, schoolhouses,
jails, “Fountain of Youth”, museums, houses, and lighthouses. There are over 150,000 sites of
archaeological importance within St. John’s County. According to the Florida Department of
Environmental Protection, there were 4400 permits issued for historical preservation sites in St. John’s
County in 2008.
Slide 6: Background Hurricanes
It is also important to understand the extent of each of the 3 categories being studied.
According to the National Oceanic and Atmospheric Administration (NOAA), major hurricanes are listed
as Category 3 and above.
There has not been a major hurricane direct landfall in St. John’s County ever. The last hurricane
to actually directly hit this area was Hurricane Dora in 1964(Cat.2) (NHC, NOAA). The area is not prone
to taking direct hits from hurricanes because of the curvature of the coastline just to the North of here.
Hurricanes tend to stay at sea as long as possible. They try to avoid landfall even when it is inevitable.
They are funny that way. The last major hurricane to make landfall on the East coast was hurricane
Jeanne (Cat.3) back in 2004 in South Florida (NHC, NOAA).
Methods: Discussion (no slide)
The methods used in this study were from tools in Arc Map, Arc Catalog, and Adobe Illustrator. The
download of data was from the Florida Geographic Data Library and St. John’s County GIS Data Depot.
Layers were downloaded to include St. John’s County shape file, cntbnd shape file, DEM for elevation,
historic structures for St. John’s County, water shape file, TIFF image of St. John’s County, and Roads
shape file. I tried to find flood zones data without success. There were conflicting files and it was
determined that they were not required to get flooded areas for each storm type.
Arc Catalog was used to ensure all data layers were in same coordinate system for calculations.
The calculations included transforming elevation layer from meters to feet using times tool in Arc
toolbox, designating area of elevation using less than equal tool for 3 levels of flooding, use of Adobe
illustrator to highlight area of discussion including downtown St. Augustine and area of high density of
historic sites.

3. Slide 7: Elevation
It is found through analysis of elevation data that much of St. John’s County has very low
elevation. In fact, the highest elevation is just above 75 ft. This makes the area very prone to flooding
due to storm surge.
The distribution of the 4400 historic sites is also important to notice. Most of the historic sites
are clustered in the downtown region of St. Augustine. Other clusters of sites are located in the South
West Region of the study area, along the coast in the North and South parts of St. John’s County, and
along the St. John’s River to the West. The location of these sites put them in critical danger if flooding
were to occur due to storm surge during a hurricane.
Slide 8: Downtown St. Augustine
This is a closer look at downtown St. Augustine. The majority of historic sites within St. John’s
County are clustered together in this area. Noticing the sheer number of sites downtown, their
proximity to the intracoastal waterways, and the low elevation of this area, it is easy to see the dangers
that a moderate storm surge would have on the structures. Imagine the effects of a storm surge of 9-18
feet.
Slide 9: Flood Analysis Category 3 Hurricane
This is the analysis of flooded lands in a Category 3 hurricane. The study shows that 29.179% of
total areas of St. John’s County will become flooded. All historic sites within ~ 1.5-2 miles of coast will
flood. Historical sites along St. John’s River will be under water as arterial rivers and canals overflow.
Downtown St. Augustine shows full engulfment due to flood waters. Approximately half of the historic
structures (over 2000) in the county are destroyed due to storm surge.
Slide 10: Flood Analysis Category 4 Hurricane
This is the same analysis in a Category 4 hurricane. The analysis shows that 34.39% of total areas
will flood. All historic sites within ~ 2- 2.5 miles of the coast will flood. Historic sites along St. John’s River
will be under water. Additional flooding will occur along arterial rivers and canals moving eastward and
covering most areas of South West St. John’s County. Historic Downtown St. Augustine will be
completely destroyed due to storm surge. Flooding moves West past US 1 and engulfs more than 70% of
historic sites.
Slide 11: Flood Analysis Category 5 Hurricane
This is the final analysis in the case of a Category 5 hurricane. The analysis shows that 47.23% of
the total areas will flood. All historic sites within ~ 3-4 miles of the coast will be under water. All historic
sites along St. John’s River will be completely destroyed. Complete flooding of Western portions of St.
John’s County including all arterial rivers and canals will occur. Nearly 90% of all historic sites will be
destroyed in St. John’s County due to the storm surge.
Slide 12: Wind Damage Guidelines NOAA
Category 3: Poorly constructed frame homes can be destroyed by the removal of the roof and
exterior walls. Unprotected windows will be broken by flying debris. Well-built frame homes can
experience major damage involving the removal of roof decking and gable ends.

4. Category 4: Poorly constructed homes can sustain complete collapse of all walls as well as the
loss of the roof structure. Well-built homes also can sustain severe damage with loss of most of
the roof structure and/or some exterior walls. Extensive damage to roof coverings, windows,
and doors will occur. Large amounts of windborne debris will be lofted into the air. Windborne
debris damage will break most unprotected windows and penetrate some protected windows
Category 5: A high percentage of frame homes will be destroyed, with total roof failure and wall
collapse. Extensive damage to roof covers, windows, and doors will occur. Large amounts of
windborne debris will be lofted into the air. Windborne debris damage will occur to nearly all
unprotected windows and many protected windows. (NHC, NOAA)
Slide 13: Results
Category 3:
29% of total lands flooded due to storm surge. Historical site along coastline and along St. John’s River
are under water. Downtown St. Augustine is under water. Nearly 50% of all historical sites are under
water. Wind damage would also be substantial.
Category 4:
34% of total lands flooded. Historical sites within 2.5 miles of coastline destroyed. Historic sites along St.
John’s River destroyed including along arterial rivers and canals. 70% of all historical sites are under
water. Wind damage at catastrophic levels.
Category 5:
47% of total lands flooded. Historical sites within 3.5 miles of coast line are completely destroyed due to
storm surge. Sites along St. John’s River and all arterial rivers and canals destroyed. 90% of historical
sites are under water. All structures completely destroyed by storm surge and wind damage.
Slide 14: Conclusion
The importance of the historical sites to St. John’s County is evident. The tourism in St. John’s
County is the only viable means of income to this area. These historic sites bring a unique experience to
all of the visitors of the area. St. John’s residences lifestyles and financial freedoms are interconnected
with the existence of the historical sites of the 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. The tourism would become non-existent
and many people would be force to relocate. We have seen this before with Katrina in New Orleans. The
economy could not sustain itself without the existence of the unique history of St. Augustine and St.
John’s County.
This study was a dooms day scenario. Hurricanes have traditionally remained well off our coast.
We can only hope that this remains the case. It has been a long time since St. John’s County has had a
direct landfall from any hurricane much less a major one. It would be catastrophic. However, this study
also shows the importance of readiness in the face of crisis. With this information, it is my hope that

5. local and government official put more thought into protecting these structures if this were ever to
occur. Maybe new laws laying out formal plans to protect historical structure are in our near future.
Slide 15: References
Corbett, Theodore G. “Migration to a Spanish Imperial Frontier in the Seventeenth and Eighteenth
Centuries: St. Augustine”, Hispanic American Historical Review, Vol. 54. No. 3 (Aug. 1974), pp.414-430.
Wolkomir, R. “In Search of St. Augustine”, The Smithsonian, Vol. 32, No. 7 (October 2001), pp. 114-120.
Historical Markers of Florida, Division of Historical Resources, Florida Historical Markers Program,
Florida Heritage.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/