Water bodies, watersheds and storm water
Double Run Spring main view
Double Run Spring
Location
Double Run Spring is located about 1.0 mile north of Howey Height, to the west of County Road 561. The spring is located on private property.
Latitude 28°40’44” N, Longitude 81°44’31” W
Sec. 7, T 21 S, R 20 E
Double Run Spring run
Description
Double Run Spring is a third-magnitude spring that discharges in a swampy area. Permission to locate the spring source has not been obtained from the landowner. The spring may be a surficial aquifer seep.
Discharge
St. Johns River Water Management District (SJRWMD) has measured discharge at Double Run Spring from 1991 to 2010 and currently measures discharge twice per year. Discharge is measured at the location where the run crosses the road. The difference between the minimum and maximum discharges is 6.25 cubic feet per second (cfs) over the period. The maximum discharge of 6.98 cfs was measured in September 1999; the minimum discharge of 0.73 cfs was measured in May 2001. The mean and median discharges for the period from 1991 to 2010 are 2.50 cfs and 2.22 cfs, respectively (see the table below).
Double Run Spring Discharge Graph
Water quality
Double Run Spring was sampled 14 times by SJRWMD, from 1998 to 2005. The U.S. Geological Survey sampled the spring in 1997 and 1999, and Lake County sampled the spring twice in 2004. Summary statistics of the water quality data for selected variables are shown in the table below.
Double Run Spring Water Quality Graph
Summary statistics of water quality and discharge at Double Run Spring
| Double Run Spring | Min | Mean | Median | Max | Count | Period |
|---|---|---|---|---|---|---|
| Discharge, cfs | 0.73 | 2.50 | 2.22 | 6.98 | 30 | 1991–2010 |
| Alkalinity, total, mg/L as CaCO3 | 42.4 | 48.0 | 48.2 | 52.0 | 17 | 1998–2005 |
| Calcium, total, mg/L as Ca | 16.5 | 20.6 | 21.0 | 21.7 | 16 | 1998–2005 |
| Chloride, total, mg/L as Cl | 7.1 | 12.0 | 12.1 | 13.6 | 18 | 1997–2005 |
| Dissolved Oxygen | 4.30 | 5.45 | 5.64 | 6.28 | 10 | 1999–2004 |
| Fluoride, total, mg/L as F | 0.05 | 0.06 | 0.06 | 0.10 | 10 | 1998–2002 |
| Magnesium, total, mg/L as Mg | 6.7 | 8.7 | 8.6 | 10.1 | 17 | 1998–2005 |
| Nitrate + nitrite, total, mg/L as N | 2.82 | 4.14 | 4.04 | 5.28 | 15 | 1998–2005 |
| Orthophosphate, total, mg/L as P | 0.01 | 0.02 | 0.02 | 0.02 | 13 | 1998–2004 |
| pH, field | 6.77 | 7.25 | 7.21 | 8.10 | 17 | 1997–2005 |
| Phosphorus, total, mg/L as P | 0.01 | 0.04 | 0.03 | 0.11 | 14 | 1998–2005 |
| Potassium, total, mg/L as K | 2.3 | 3.1 | 3.0 | 3.9 | 16 | 1998–2005 |
| Sodium, total, mg/L as Na | 4.0 | 4.6 | 4.5 | 5.4 | 17 | 1998–2005 |
| Specific conductance, field, µmhos/cm at 25°C | 114 | 208 | 214 | 239 | 17 | 1998–2005 |
| Specific conductance, lab, µmhos/cm at 25°C | 305 | 307 | 307 | 309 | 2 | 1997–1999 |
| Sulfate, total, mg/L as SO4 | 10.3 | 17.9 | 18.8 | 20.2 | 16 | 1998–2005 |
| Total dissolved solids, mg/L | 123 | 144 | 137 | 191 | 18 | 1997–2005 |
| Water temperature, °C | 18.7 | 23.3 | 23.8 | 26.2 | 18 | 1997–2005 |
mg/L = milligrams per liter
cfs = cubic feet per second
