One of the ways that springs are classified is by the volume of the water they discharge. Many springs are measured regularly, while some have never been measured. The largest springs are called "first-magnitude," defined as meaning they discharge at least 100 cubic feet of water per second (cfs), or about 64.6 million gallons per day (mgd). The scale for spring flow is as follows:
0 Magnitude - no flow (sites of past/historic flow)
1st Magnitude - > 100 cubic feet per second (cfs)
2nd Magnitude - 10 - 100 cfs
3rd Magnitude - 1 - 10 cfs
4th Magnitude - 100 gal/min (gallons per minute) - 1 cfs (448 gal/min)
5th Magnitude - 10 to 100 gal/min
6th Magnitude - 1 to 10 gal/min
7th Magnitude - 1 pint to 1 gal/min
8th Magnitude - Less than 1 pint/min (Rosenau et al., 1977, p. 4, as adapted from Meinzer, 1927, p. 3)
The 1977 update of Springs of Florida (Rosenau et al.) identified and measured 27 first-magnitude springs. Since the 1977 publication, 4 of the original 27 "springs" (Kini, Riversink, Falmouth, and Natural Bridge) have been reclassified as "karst windows" rather than as true springs (Wilson & Skiles, 1989). Formerly called "spring-sink combinations," karst windows are characterized by water that rises from underground, flows a short distance (typically between 100 and 300 yards), and then drains back underground again into a sinkhole. Karst windows have also been described as "long sinkholes"--sites where the surface collapsed above a several-hundred-foot section of the Floridan Aquifer instead of over a pinpointed spot. Scott et al., define karst windows as sites "where the roof of a cave collapsed exposing an underground stream for a short distance" (2002, p. 6). Rhodes Springs (Leon County), Double Spring (Jackson County), and Owens Spring (Lafayette County) have similar characteristics and should more properly be called karst windows..
In another and related classification development, hydrologists now characterize river rises as springs. These are sites where some or all the water from a river (e.g., the Santa Fe, Steinhatchee, Alapaha, Aucilla, and St. Marks) re-surfaces after flowing some distance underground. Several river rises occur along the western edge of the Ocala uplift, an upward bulging of the limestone layer that overlays the Floridan Aquifer. The Suwannee is the only river that traverses the Ocala uplift without flowing underground. Over time, the Suwannee cut through the limestone, which is one of the reasons it has 200 springs in its watershed. Although they are classified as springs, these river rises have water that has not undergone the filtration of that in traditional springs and is not clear.
Hornsby and Ceryak have since classified several other first-magnitude springs along the Suwannee River basin, increasing the total number of such springs to the current count of 33. The total flow from these springs likely exceeds the flow of all the other springs in the world combined.
Which Spring is Biggest?
Not that it matters, really . . . after all, this is not some sort of hydrologic contest. But, lots of people want to know. The answer is that it all depends on how spring flow is measured, where it is measured from, and how many flow points are counted as a (as in a single) spring. Silver Springs is often called the largest freshwater spring in Florida if not in the U.S., with an average flow of 820 cfs or about 530 MGD. However, as noted in both the 1947 and 1977 editions of Springs of Florida, only about half of this total is from the main spring vent at the headwaters of Silver River. The rest of the flow is from other springs as far as 3,500 feet below the headspring (Rosenau et al., 1977, pp. 276-79). Therefore, the total flow from the main spring at Silver Springs is probably more like 400-500 cfs. These various vents have water with different temperatures, which means the waters come from different depths or directions and are, in essence, different springs.
The total flow from King's Bay (Crystal River) is averages between 800-900 of 820 cfs, but that amount represents the combined output of over a dozen'--some say as many as 100'--springs. The story is similar for Rainbow Springs, which has an average flow of 760 cfs but which must be divided by at least a dozen springs stretched over 1.5 miles.
Several river rises have average flows that exceed 400 cfs (St. Marks, ALA112971, Santa Fe Rise, Alapaha Rise, and Nutall Rise), but some purists do not truly consider these quite the same way as clear-water springs that have undergone more filtering and spent more time underground. For the most part, water in the river rises is basically the same water that was flowing aboveground, upriver, just a few hours or days before.
Then there is the special case of Spring Creek in Wakulla County. This cluster of submarine springs'--most of them just offshore'--has a total flow of about 2,000 cfs. The upper section of these springs, with at least five springs of which two are likely 1st magnitude, has a total flow of 764 cfs. The middle section, with at least four springs of which two are likely 1st magnitude, has a total flow of 346 cfs. The lower section, with an unknown number of springs (note: the authors have only found descriptions of two vents), has a total flow of 893 cfs. There is no measurement of the individual springs, but some of them could be as large as 400 cfs or larger. In addition, these springs appear to flow with a mixture of fresh and salt water, although they have been very little studied. The flow from these spring varies greatly, depending on the tide and other conditions.
So again, which is the largest single freshwater spring? If river rises are counted, it is Alapaha Rise in Hamilton County. If it is a clear-water spring, the "winner" is probably Silver Springs, with Wakulla Springs close behind, the latter of which has an average flow of 390 cfs. And where do the large flows at Spring Creek fit, all of which have huge flows (at least, under certain tidal conditions), but none of which has been measured independently?
In other words, it depends on how you look at it, and you're safest bet is to not get caught in this silly discussion in the first place.
Will there be More than 33?
There is a good chance that there are other first-magnitude springs yet to be discovered or measured. Moreover, as scientists learn more about the springs of Florida, there may be additional reclassifications. For example, the Crystal River, Wacissa, Chassahowitzka, Rainbow, and Spring Creek spring groups each contain over a dozen springs, but their flow is measured as a total amount for each group. In some cases, springs within a group may be miles apart and have different content characteristics and recharge areas. Traditionally, this flow-combining was done because of the difficulty of differentiating the individual flows from springs that were near to each other or just because there was not the person-power or money devoted to studying them. More advanced methods of measurement may now be employed for precise flow figures.
The authors argue that springs within such groups should be measured separately. Doing so will give a clearer picture of the flow of individual springs of Florida, their fluctuations, sources, flow patterns, chemical components, and impacts on them. And while the authors accept that river rises meet the technical definition of a spring, this acceptance is a little begrudging. Lacking the filtration and clear water of other springs, river rises simply do not have the aesthetic, personal, or visual appeal of "traditional" springs.
And although a number of submarine spring have been identified--some were known to early explorers in the 1500s and 1600s--they have been little studied to date. It is a virtual certainty that some of these offshore springs would have first-magnitude flow.
The following chart lists the currently identified first-magnitude springs in Florida, in order by size, with notations of their classification type and their ownership status. Note that ownership status does not necessarily translate to accessibility or level of protection. Many privately owned springs are easy to reach and see, while some in public hands require strenuous effort to locate. In the main document, there is detailed information on these individual first-magnitude springs regarding use, access, and protection.
It is also worth noting that large springs, like small springs, have fluctuations in the volume of their flow. During 1998-2001, north and central Florida underwent a sustained period of drought. Flows from most springs were lower than historic levels. Three large flow sites--Falmouth Spring (now classified a Karst Window), Lime Spring, and Hornsby Spring--stopped flowing altogether. Wakulla Spring holds the distinction of having the greatest recorded range of flow of any spring in the world--from a low of 25 ft3/sec. (or 16,150,000 gallons per day) to 1,910 ft3/sec. (or about 1,230,000,000 gallons a day).
First-Magnitude Springs and Spring Groups in Florida
|1||Spring Creek||Spring Group||Wakulla||
||State & Private|
|2||Crystal River (King's Bay)||Spring Group||Citrus||
||State & Private|
|4||Alapaha Rise||River Rise||Hamilton||
|5||St. Marks Rise||River Rise||Leon||
||State & Private|
|6||Nutall Rise (Aucilla River)||River Rise||Jefferson||
|8||Santa Fe Rise||River Rise||Columbia||
|9||Santa Fe Spring (ALA112971)||Single Spring (+River Rise)||Alachua||
|10||Steinhatchee Rise||River Rise||Taylor||
||State & Private|
|13||Siphon Creek Rise (Santa Fe River)||River Rise||Gilchrist||
|16||Columbia||Single Spring (+River Rise?)||Columbia||
|18||Lime Sink Run||Single Spring||Suwannee||
|19||Holton Creek Rise||River Rise||Hamilton||
|24||COL 61981||Single Spring||Columbia||
|27||Silver Glen||Single Spring||Marion||
|29||Devil's (Little, Ear, Eye)||Spring Group||Gilchrist||
|30||Weeki Wachee||Single Spring||Hernando||
*The springs identified as being privately owned are accessible by water, as they form navigable waterways. On occasion, such as in times of drought, their runs are too shallow to navigate. Private individuals cannot "own" a spring that is along/accessible from a navigable waterway. They own the land around it above the normal high water mark. Access to some springs adjacent to private land can create confrontations, and spring visitors should be wary and keep off private land, especially if it is posted.
These data are based the January 2000 flyer from the Florida Department of Environmental Protection, "Status of the First Magnitude Springs in Florida," compiled by Jim Stevenson and Frank Rupert. The compilers of this flyer cite the references below. Additional narrative is added by JF.
Ferguson et al., 1947, Springs of Florida. Tallahassee, FL: Florida Geological Survey Bulletin #31.
Hornsby, D., & Ceryak, 1998. Springs of the Suwannee River Basin in Florida. Live Oak, FL: Suwannee River Water Management District. (Phone: 800-226-1066)
Hornsby, D., & Ceryak, 2000. Springs of the Aucilla, Coastal, and Waccasassa Basins in Florida. Live Oak, FL: Suwannee River Water Management District. (Phone: 800-226-1066)
Lane, E., 2001. The Spring Creek Submarine Springs Group, Wakulla County, Florida. Tallahassee: Florida Geological Survey.
Rosenau et al., 1977. Springs of Florida. Bulletin 31 (Revised). Tallahassee: State of Florida, Department of Natural Resources, Division of Resource Management, Bureau of Geology. (Available on the Internet at http://www.flmnh.ufl.edu/springs_of_fl/aaj7320/index.html)
Wilson, W.L., & Skiles, W.C., 1989. "Partial Reclassification of First-Magnitude Springs in Florida," in Beck, B.F. (ed.), Engineering and Environmental Impacts of Sinkholes and Karst. Proceedings of the Third Multidisciplinary Conference on Sinkholes and the Engineering and Environmental Impacts of Karst, pp. 65-72.