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Tuesday, July 01, 2008

Fanning Springs

Recently I saw information in the news and subsequently posted information about how Fanning Springs no longer emits enough water to be categorized a first-magnitude spring. I contacted Tom Greenhalgh at the Florida Geological Survey in regards to this to get further information. Below is some of the information that I received.

Fanning Springs is now a “historical” first magnitude spring. The median discharge value is now being used for classification (Copeland, R.E., comp. 2003. Florida Spring Classification System and Spring Glossary Tallahassee: Florida Geological Survey, Special Publication no. 52, 17 pp. - PDF) not, classifying any spring with a historical discharge measurement that exceeded 100 cubic feet per second (cfs) as a first magnitude spring. Discharge data in Fanning Springs between 1997-2008 had a median discharge of 71.38 cfs.

Most springs have only a limited number of historical discharge measurements. Now, with real-time discharge measurements being collected at some springs we are obtaining daily discharge measurements. I recently compiled the available discharge data for Fanning Springs and have provided preliminary statistical results from Dr. Rick Copeland for you below. Duplicate measurements in the dataset were not eliminated. Also, there is some debate on whether Fanning Springs backflows.

1. There is a near natural break in discharge at the end of December 1998 and January 1999.

2. Flow from October 1930 through December 1998 (68 years)
Mean = 104 cfs (discharge)
Median = 108 cfs (discharge)
Max = 188 cfs (discharge)
N (no. of samples) = 23

3. From January 1999 through June 9, 2008
Mean = 65 cfs (discharge)
Median = 69 cfs (discharge)
Max = 247cfs (discharge)
N = 2646

4. Of 2464 daily measurements (including dupes) since January 1, 1999, 136 measurements were negative. That is surface water flowed into Fanning Spring
Mean = 54 cfs (recharge)
Median = 62 cfs (recharge)
Max = 108 cfs (recharge)
N = 136

The Florida Geological Survey does not have a publication planned that will reclassify the first magnitude springs based on the 2003 definition and currently available discharge data.

If you have additional comments or questions, please feel free to contact me.

Tom Greenhalgh, P.G.
Florida Geological Survey
Hydrogeology Section
Department of Environmental Protection
903 West Tennessee Street MS#720
Tallahassee, Florida 32304-7700

Related Info:
Excerpts from editorials in Florida newspapers
Nelson wades into watery woes

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