Water bodies, watersheds and storm water
Sharks Tooth Spring main view
A view of Sharks Tooth Spring run
Sharks Tooth Spring
Location
Sharks Tooth Spring is located in the Seminole State Forest about 2 miles southeast of Cassia. From the south entrance of Seminole State Forest on State Road 46 (about 0.4 mile west of the Wekiva River), turn north and drive past the stop sign, through the gate, and cross the bridge over Black Water Creek. Drive about 0.2 mile from the bridge to the next intersection, then turn right and go another 0.9 mile. Park by picnic table area, and walk on trail for about 500 feet to spring. Access and fee information can be obtained at the Seminole State Forest south entrance.
Latitude 28°52’23.73” N, Longitude 81°26’24.10” W
SE¼ SW¼ SW¼ sec. 32, T 18 S, R 29 E
Description
Sharks Tooth Spring is a fifth-magnitude spring that emerges from the weathered limestone and clay at the base of a hillside. There is no pool at the spring head. The spring run is about 2 feet wide and flows about 800 feet toward the northeast to Sulphur Run. Camping, hiking, and equestrian trails are nearby within the Seminole State Forest.
Another view of Sharks Tooth Spring run
Discharge
Discharge at Sharks Tooth Spring was measured by the U.S. Geological Survey (USGS) in 1997 and 2001 and by St. Johns River Water Management District (SJRWMD) in 2005 and 2008. The mean discharge was 0.18 cubic feet per second.
Water quality
Sharks Tooth Spring was sampled by USGS in 1997 and 1999, twice by Lake County in 2004, and by SJRWMD in 2005 and 2008. A summary of the water quality data for selected variables is shown in the table below.
Summary statistics of water quality and discharge at Sharks Tooth Spring
| Sharks Tooth Spring | Min | Mean | Median | Max | Count | Period |
|---|---|---|---|---|---|---|
| Discharge, cfs | 0.10 | 0.18 | 0.18 | 0.28 | 6 | 1997–2008 |
| Alkalinity, total, mg/L as CaCO3 | 105.0 | 107.3 | 106.7 | 110.0 | 5 | 2004–2005 |
| Calcium, total, mg/L as Ca | 54.4 | 56.5 | 56.5 | 60.5 | 5 | 2004–2005 |
| Chloride, total, mg/L as Cl | 79.9 | 95.1 | 91.3 | 110.0 | 6 | 1997–2005 |
| Dissolved Oxygen | 1.50 | 1.55 | 1.55 | 1.60 | 2 | 2004 |
| Magnesium, total, mg/L as Mg | 15.1 | 17.1 | 16.4 | 20.8 | 5 | 2004–2005 |
| Nitrate + nitrite, total, mg/L as N | 0.01 | 0.15 | 0.14 | 0.32 | 5 | 2004–2005 |
| Orthophosphate, total, mg/L as P | 0.03 | 0.04 | 0.05 | 0.06 | 3 | 2005 |
| pH, field | 7.11 | 7.50 | 7.56 | 7.90 | 7 | 1997–2005 |
| Phosphorus, total, mg/L as P | 0.05 | 0.06 | 0.06 | 0.07 | 4 | 1999–2005 |
| Potassium, total, mg/L as K | 1.4 | 1.9 | 2.0 | 2.5 | 5 | 2004–2005 |
| Sodium, total, mg/L as Na | 46.9 | 50.0 | 50.6 | 51.9 | 5 | 2004–2005 |
| Specific conductance, field, µmhos/cm at 25°C | 677 | 689 | 680 | 710 | 5 | 2004–2005 |
| Specific conductance, lab, µmhos/cm at 25°C | 612 | 700 | 657 | 817 | 5 | 1997–2005 |
| Sulfate, total, mg/L as SO4 | 82.3 | 111.8 | 93.7 | 200.0 | 5 | 1997–2005 |
| Total dissolved solids, mg/L | 349 | 396 | 396 | 430 | 6 | 1997–2005 |
| Water temperature, °C | 22.2 | 22.8 | 22.7 | 23.6 | 7 | 1997–2005 |
mg/L = milligrams per liter
cfs = cubic feet per second
Age of discharge water
The age of water discharging from Sharks Tooth Spring was determined by measuring the concentration of tritium, carbon-14, and carbon-13 in the spring discharge, which was measured in March 2005. Sharks Tooth Spring had a tritium concentration of 1.43 tritium units, a carbon-14 concentration of 34 percent modern carbon, and a delta carbon-13 value of –10.14 parts per thousand. The tritium concentration suggests that the water is less than 50 years old. The carbon-14 concentration of 34% modern carbon can result from the reaction of rainfall with calcite, dolomite, and soil organic matter, and the mixing with Lower Floridan water.
