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Dear FGS friends and customers,

Summer has been particularly busy at the FGS in the wake of numerous sinkhole events and related media coverage, which included FGS “air-time” on CBS Sunday Morning. In addition, thanks to the outstanding work of the DEP Office of External Outreach & Public Education, the Florida Specifier ran in its July 2013 issue an informative article about FGS research and mapping activities, which you can read here. We are also excited by new research opportunities regarding geologic mapping and sinkholes, thanks to two recently awarded grants. As always, please contact us if you have any questions.

Best regards,

Jonathan D. Arthur, Ph.D., P.G.
Director and State Geologist
Office of the Florida Geological Survey
Florida Department of Environmental Protection

In This issue Bar

•FGS Receives Sinkhole Vulnerability Mapping Grant   More…

•FGS Releases Sinkhole Information More…

•Beach Sand Studies Aid Design Of More Efficient Desalination Process   More…

•FGS Director Named President-Elect Of National Association More…

•Ever Wonder Why States Have Geological Surveys? More…

•See Previous Editions Of FGS News And Research More…

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CONTACT: DEP Press Office, 850.245.2112, 


~Federal Emergency Management Agency grant will help form a statewide
assessment of sinkhole vulnerability~

TALLAHASSEE – A $1.08 million federal grant will allow the Florida Geological Survey, in conjunction with the Florida Division of Emergency Management, to conduct a statewide assessment of sinkhole vulnerability in Florida starting this fall.

The grant was funded by the Federal Emergency Management Agency in conjunction with the Florida Division of Emergency Management. The three-year project will start with geologists conducting a one-year pilot study in Hamilton, Columbia and Suwannee counties.The results of the pilot study will culminate in the production of a model that will generate a map showing the relative vulnerability of these counties to potential sinkhole formation. The resulting model will then be used to produce a statewide map during the following two years.

“Florida’s geology is complex and this grant will allow the Florida Geological Survey to produce a predictive tool that will refine our understanding of sinkhole occurrence throughout the state,” said Dr. Jon Arthur, Director of the Florida Geological Survey. “Ultimately, this assessment will aid planners, builders and environmental regulators for the betterment of human health and safety as well as the economy.”

Sinkholes are a common, natural feature of Florida's landscape because Florida sits on several thousand feet of porous limestone. Porous limestone aquifers can produce billions of gallons of fresh water. Naturally acidic groundwater and rainwater dissolves limestone, leaving behind void spaces. The resulting void spaces can lead to the formation of sinkholes, caves, and springs, all of which are called karst features.

The information gathered will help improve the State of Florida Enhanced Hazard Mitigation Plan risk assessment section on sinkholes as well as its corresponding mitigation strategies. An appendix to the State Hazard Mitigation Plan will be added to the project’s full findings.  

“The Florida Division of Emergency Management is pleased to be a part of this project,” said FDEM Director Bryan W. Koon. “Sinkholes present a potential hazard to many Floridians throughout the state. By better understanding sinkhole vulnerability in Florida, we will be better able to prevent loss of life and property and keep Florida’s families safe.”

The request was sparked by Tropical Storm Debby, which brought heavy rainfall to Florida in June 2012, triggering the formation of sinkholes. In the months leading up to Tropical Storm Debby’s record rainfall event, most of Florida had been experiencing extreme drought conditions, resulting in lowered water levels in our aquifers. The result was an outbreak of sinkholes when rainwater caused dry underground voids -- previously filled with water -- to collapse.

Benefits of the project include more effective mitigation planning to reduce loss of life and property by lessening the impact of sinkholes on Florida’s population and infrastructure; better understanding of sinkhole susceptibility; an increased understanding of Florida's karst terrain and hydrogeology, and how that affects the state. The assessment will help environmental regulators, growth management planners, the construction industry and local governments in developing protective designs as additional information about Florida's geology will facilitate planning for possible sinkhole occurrences.

For more information about sinkholes, visit DEP's Online Newsroom or the Florida Geological Survey website..

Contact person/info: Clint Kromhout 

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CONTACT: DEP Press Office, 850.245.2112, 



~Facts and information about encountering sinkholes in the state of Florida~

TALLAHASSEE – The Florida Department of Environmental Protection’s Florida Geological Survey has compiled the following information to provide a single point source for general knowledge about the nature of sinkholes in the state of Florida and additional information about proper protocol should you ever encounter a sinkhole in an urban area.

Facts about sinkholes in Florida:

-The entire state of Florida sits on top of several thousand feet of limestone. Limestone is a rock that can form with natural void spaces called porosity.  In limestone where the void spaces are connected, the rock is permeable.  Porous and permeable limestone makes great aquifers and provide millions of gallons of fresh drinking water for residents and agriculture. The most significant factor in the development of sinkholes is the dissolution of the limestone underlying Florida by naturally acidic groundwater.

 -Sinkholes are a natural and common feature of Florida's landscape. They are only one of many kinds of karst landforms, which include depressions, caves (both air and water filled), disappearing streams, springs and underground aquifer systems, all of which occur in Florida. Thousands of naturally occurring sinkholes can be seen throughout the state of Florida including many that connect underground to springs, rivers and lakes.

-Sinkholes form in karst terrain from the collapse of surface sediments into underground voids. In Florida one may see solution sinkholes, cover-subsidence sinkholes or cover-collapse sinkholes. The first two types will show very little topographical disturbance to the naked eye, while the third is the type which shows a abrupt change in topography and is most associated with the thought of sinkholes.  

Questions about sinkholes in urban and suburban environments:

-My yard is settling... Do I have a sinkhole? Maybe. But a number of other factors can cause holes, depressions or subsidence of the ground surface. Expansive clay layers in the earth may shrink upon drying, buried organic material, poorly-compacted soil after excavation work, buried trash or logs and broken pipes all may cause depressions to form at the ground surface. These settling events, when not verified as true sinkholes by professionals, are collectively called "subsidence incidents." If the settling is affecting a dwelling, further testing by a licensed engineer with a licensed geologist on staff or a licensed geology firm may be in order. Property insurance may pay for testing, but in many cases insurance may not cover damage from settling due to causes other than sinkholes.

-A sinkhole opened in my neighborhood... should I be concerned? Although sinkholes in Florida sometimes occur in sets, most are isolated events. The bedrock underlying the state is honeycombed with cavities of varying size, most of which will not collapse in our lifetimes. A quick inspection of your property for any sinking or soft areas might be prudent. Unless the sinkhole is very large, and extends to your property, there’s likely to be little reason for concern.

Should a sinkhole open in an area near you the hole should be immediately cordoned off and clearly marked to protect traffic. Contact local law enforcement to report the hazard and call your city or county road department to initiate repair work. If the road is private, repair of the hole is usually the responsibility of the landowner or property owners’ association.

-Is there a safe area of Florida where there is no chance of sinkholes? Technically, no. Since the entire state is underlain by carbonate rocks, sinkholes could theoretically form anywhere. However, there are definite regions where sinkhole risk is considerably higher. In general, areas of the state where limestone is close to surface, or areas with deeper limestone but with a conducive configuration of water table elevation, stratigraphy, and aquifer characteristics have increased sinkhole activity.

Additionally, the Department announced Friday that the Florida Geological Survey, in conjunction with the Florida Division of Emergency Management, has received a $1.1 million grant from the Federal Emergency Management Agency to address sinkhole vulnerability. Find more information here.

Contact person/info: Clint Kromhout 

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Florida beach sand

Desalination of seawater using the reverse osmosis process can be made less costly by the use of subsurface intake systems along sandy beaches. Quality of the raw water can be greatly improved by the use of subsurface intakes, substantially reducing treatment cost. The active shorelines of Florida are well-suited for the development of beach gallery intake systems. These systems are installed beneath the active beach between the high and low tide zones. These galleries are simple to construct and the active wave action within the intertidal zone continuously cleans the filter face.  

A comprehensive study of the grain-size characteristics of Florida beaches conducted by the Florida Geological Survey has allowed an assessment to be made of the hydraulic conductivities of Florida beach sands. Hydraulic conductivity values generally range from 1.8 to 24 meters per day, which is sufficient to allow the design and construction of high-capacity galleries at reasonable cost. This type of intake is particularly relevant to the Northeast Florida shoreline adjacent to an area being considered for development of a large-capacity seawater desalination system.

For more information see:

Missimer T.M., Maliva, R.G., Dehwah, A.H.A., and Phelps, D.C., 2013, Use of beach galleries as an intake for future seawater desalination facilities in Florida and globally similar areas: Desalination and Water Treatment,

Contact person/info: Dan Phelps 

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CONTACT: DEP Press Office, 850.245.2112, 



~Association of American State Geologists elect Dr. Jonathan Arthur to executive office~

TALLAHASSEE – The Florida Department of Environmental Protection’s Florida Geological Survey Director Dr. Jonathan Arthur was chosen as president-elect of the Association of American State Geologists on Wednesday. The election took place at the association’s 105th annual meeting in South Dakota.

“Under the leadership of Dr. Arthur, the Florida Geological Survey has provided the Department and state’s water management districts with an exceptional understanding of Florida’s complex geology through extensive research,” said DEP Deputy Secretary of Regulatory Programs Jeff Littlejohn. “This honor is a testament of his commitment to contributing research that helps the Department better protect Florida’s environment.”

Arthur joined the association as Florida’s state geologist in 2009 and served as the association’s vice president for the 2012 term. The association’s members voted based on the nominating committee’s recommendation of Arthur, who will take office July 1. In his new role as president-elect, Arthur will be responsible for coordinating two national strategic meetings that will serve as a platform for liaisons of federal and state agencies to discuss the growing natural challenges society faces and develop strategies to efficiently combine research efforts and resources to provide solutions.

Arthur has dedicated his time and knowledge to the Department for more than 30 years, beginning his tenure at the Florida Geological Survey as a research assistant in 1984. Now as director, Arthur is responsible for the oversight and direction of the state’s premier institution specializing in geosciences research and assessments. As state geologist, Arthur represents Florida regarding geological issues at a local, state and national level. In March, Arthur participated in a national sinkhole briefing for the House of Natural Resources Committee in Washington, DC.

In addition to his role within the Department, Arthur is also a member of the Florida Board of Professional Geologists, a fellow of the Geological Society of America and served as past president of the Florida Association of Professional Geologists.  

"The Association of American State Geologists Foundation supports the mission of the Association especially with regard to education and outreach activities," said president of the Association of American State Geologists Foundation David Wunsch. "Jon is nationally recognized for his outreach skills as demonstrated by his activities related to sinkholes, so I look forward to developing programs to educate the public and policy makers with regard to natural hazards."

The Association of American State Geologists was founded in 1908 for the purpose of advancing the science and practical application of geology in the United States. The objectives of the association are to improve the work of State Geological Surveys, improve methods of assembling data and disseminating the results and to achieve effective coordination of work with federal and state agencies. The association is made up of the chief executives of each state’s geological survey who meet annually to discuss issues and share resources.

For more information on the Association of American State Geologist’s activities and research, please visit

For a photo of Dr. Jonathan Arthur, please visit

Contact person/info: Jon Arthur 

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FDEP Office of the Florida Geological Survey | 903 W. Tennessee Street. MS 720 | Tallahassee | FL | 32304 | 850-617-0300 |