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Ponce de Leon Springs main view
photo by T. Scott, FGS
Ponce de Leon Springs pool
Ponce de Leon Springs boil
Ponce de Leon Springs
Ponce de Leon Springs is a second-magnitude spring with a semicircular pool about 190 feet from north to south and 170 feet from east to west. Spring flow is from a cavern and chimney opening in the north-central part of the pool. A low boil is visible at the surface above the opening in the limestone rock. The pool is enclosed by a low concrete wall and bordered by a concrete walk. A large bathhouse and snack bar are on the north side of the pool. The spring water flows through a concrete weir on the west wall of the pool, then down a 3-foot drop into a wide spring run. The broad but short run carries flow westward through a chain of three lakes (Spring Garden, Woodruff, and Dexter), then to the St. Johns River.
Ponce de Leon Springs is the centerpiece of De Leon Springs State Park. Swimming, boating, fishing, picnicking, and camping are a few of the attractions at this historic site. Facilities include bathhouse, refreshment stand, pancake house, and souvenir shop.
Ponce de Leon Springs spillway
Discharge at Ponce de Leon Springs was measured by the U.S. Geological Survey (USGS) from 1929 to 2002. St. Johns River Water Management District has measured discharge from 1983 to 2010 and currently measures discharge monthly. The difference between the minimum and maximum discharges is 49.4 cubic feet per second (cfs) over the period. The maximum measured discharge of 61.6 cfs occurred in August 2004; the minimum discharge of 12.2 cfs occurred in November 1997. The mean and median discharges for the period from 1929 to 2010 are 27.8 cfs and 27.1 cfs, respectively (see the table below).
Ponce de Leon Springs was sampled by USGS from 1956 to 1990, with periodic field measurements only at other times since 1932. The district sampled Ponce de Leon Springs from 1984 to 2010 and currently samples the spring four times per year. Summary statistics of the water quality data for selected variables are shown in the table below.
Summary statistics of water quality and discharge at Ponce de Leon Springs
|Ponce de Leon Springs||Min||Mean||Median||Max||Count||Period|
|Alkalinity, total, mg/L as CaCO3||99.0||119.8||120.0||184.0||109||1956−2010|
|Calcium, total, mg/L as Ca||44.0||51.4||52.0||59.0||85||1993−2010|
|Chloride, total, mg/L as Cl||39.0||131.3||120.0||272.0||211||1956−2010|
|Fluoride, total, mg/L as F||0.07||0.10||0.10||0.12||51||1989−2009|
|Magnesium, total, mg/L as Mg||9.4||13.5||13.0||19.0||86||1992−2010|
|Nitrate + nitrite, total, mg/L as N||0.25||0.83||0.85||1.36||95||1984−2010|
|Orthophosphate, total, mg/L as P||0.03||0.05||0.05||0.06||62||1972−2010|
|Phosphorus, total, mg/L as P||0.03||0.05||0.05||0.07||49||1972−2010|
|Potassium, total, mg/L as K||3.3||4.4||4.2||5.9||85||1992−2010|
|Sodium, total, mg/L as Na||46.8||84.8||80.0||137.0||86||1992−2010|
|Specific conductance, field, µmhos/cm at 25°C||378||779||755||1129||87||1984−2010|
|Specific conductance, lab, µmhos/cm at 25°C||256||663||630||1200||192||1956−2010|
|Sulfate, total, mg/L as SO4||10.0||27.0||26.5||43.0||112||1956−2010|
|Total dissolved solids, mg/L||203||416||405||612||105||1960−2010|
|Water temperature, °C||21.0||23.0||23.0||25.0||243||1932−2010|
mg/L = milligrams per liter
cfs = cubic feet per second
Age of discharge water
The age of water discharging from Ponce de Leon Springs was determined by measuring the concentration of tritium, delta carbon-13, and carbon-14 in the spring discharge, which was measured in May 1995, and tritium and helium-3, as measured in July 1995. Ponce de Leon Springs had a tritium concentration of 2.1 tritium units, which suggests that the water is less than 42 years old. The tritium/helium-3 age of the water was 28.6 years. Ponce de Leon Springs had a delta carbon-13 value of −7.96 parts per thousand and a carbon-14 concentration of 35% modern carbon, which results from the mixing of Upper and Lower Floridan aquifer water. The adjusted carbon-14 age of is recent.