In this section
Shands Bridge Spring lies under this section
of the St. Johns River.
Shands Bridge Spring
St. Johns County
Shands Bridge Spring is a submerged third-magnitude spring. The St. Johns River is about 17 to 20 feet deep near the spring. An almost circular depression (recorded by Fathometer) was observed in the bottom of the river at the spring (Spechler 1996). Groundwater is discharged from a vent at the deepest point in the spring, about 30 feet below the surface.
No actual discharge measurements have been done at Shands Bridge Spring. Discharge was estimated at 1 cubic foot per second (cfs) in 1995 (Spechler 1996).
Shands Bridge Spring was sampled by St. Johns River Water Management District in 1994 and 2007. The water quality data for selected variables are shown in the table below.
Summary statistics of water quality data at Shands Bridge Spring
|Shands Bridge Spring||Min||Mean||Median||Max||Count||Period|
|Alkalinity, total, mg/L as CaCO3||99.1||99.1||99.1||99.1||1||2007|
|Calcium, total, mg/L as Ca||92.0||92.0||92.0||92.0||1||2007|
|Chloride, total, mg/L as Cl||12.0||12.4||12.4||12.7||2||1994−2007|
|Fluoride, total, mg/L as F||0.52||0.52||0.52||0.52||1||2007|
|Magnesium, total, mg/L as Mg||42.0||42.0||42.0||42.0||1||2007|
|Potassium, total, mg/L as K||2.6||2.6||2.6||2.6||1||2007|
|Sodium, total, mg/L as Na||10.0||10.0||10.0||10.0||1||2007|
|Specific conductance, field, µmhos/cm at 25°C||826||886||886||945||2||1994−2007|
|Specific conductance, lab, µmhos/cm at 25°C||810||810||810||810||1||2007|
|Sulfate, total, mg/L as SO4||337.0||338.5||338.5||340.0||2||1994−2007|
|Total dissolved solids, mg/L||595||595||595||595||1||2007|
|Water temperature, °C||25.1||26.1||26.1||27.0||2||1994−2007|
mg/L = milligrams per liter
cfs = cubic feet per second