(6.2) SPRINGS - Rainbow Springs vs. Silver Springs
Rainbow Springs vs. Silver Springs
Natural Rainfall Patterns and Man's Groundwater Withdrawals
In This Region of the Lowered Floridan Aquifer
Seem to be Favoring
Rainbow Springs (Elevation 30 Feet)
At the Expense of
Silver Springs (Elevation 40 Feet)
An Information, Opinion, & Sources Report
Compiled by Ocklawahaman Paul Nosca
Created: 09 July 2013
Last Revised: 29 May 2015
Historically, the Silver Springs Group of the Ocklawaha River basin and the Rainbow Springs Group of the Withlacoochee River basin are inland Florida's two greatest-flowing freshwater first magnitude artesian spring groups. Records of Silver Springs flow from 1906 to 1974 show an average discharge of 820 cubic feet per second (cfs) of freshwater while data of Rainbow Springs from 1898 to 1974 display an average discharge of 763 cfs.
However, more recent flow data has revealed the following:
Silver Springs Group from 2000 to 2012 discharged an average of about 520.5 cfs of water
Rainbow Springs Group from 2000 to 2012 discharged an average of about 588.9 cfs of water
Normandeau Associates, Inc. (2011) "Restoration Plan for the Rainbow Springs and River (June 12, 2011 Draft)" (page 33, 34):
"Scientists at the SJRWMD determined in late 2010 that flow data indicated the possible migration of groundwater from the Silver Springs basin towards Rainbow Springs perhaps due to the fact that Rainbow Springs is at a lower elevation than Silver Springs by 10 feet (unpublished data presented to the Silver Springs Basin Working Group by SJRWMD, November 2010)."
SPRING RECHARGE BASIN or SPRINGSHED
Scott et al. (2004) Springs of Florida, Florida Geological Survey Bulletin No. 66 (page 20):
"A spring recharge basin, or springshed, consists of 'those areas within ground- and surface-water basins that contribute to the discharge of the spring' (DeHan, 2002; Copeland, 2003). The spring recharge basin consists of all areas where water can be shown to contribute to the ground-water flow system that discharges from the spring of interest. Because karst systems frequently include sinking streams that transmit surface water directly to the aquifer, the recharge basin may include surface-water drainage basins that bring water into the spring drainage from outside of the ground-water basin."
RAINBOW SPRINGS and RAINBOW RIVER
Flow into the WITHLACOOCHEE RIVER (South)
The headspring pool of the Rainbow Springs Group has a usual surface water elevation of about 30 feet above mean sea level (NGVD 1929).
The Rainbow River begins there and then flows south about 5.7 river miles until its junction with the Withlacoochee River (south). The Withlacoochee River then flows mostly west some 25 river miles downstream until it empties into the Gulf of Mexico. About 13 river miles of the Withlacoochee River are impounded by the Inglis Dam as the 3,400 acre (at elevation 27.5 feet) Lake Rousseau a.k.a. the Withlacoochee Backwater.
WITHLACOOCHEE RIVER BASIN U.S.G.S. STREAMFLOW GAGES
USGS 02313000 Withlacoochee River near Holder, FL (Datum = 27.52 feet)
USGS 02313100 Rainbow River at Dunnellon, FL (Datum = 24.42 feet)
USGS 02313200 Withlacoochee River at Dunnellon, FL (Datum = 0.00 feet)
USGS 02313230 Withlacoochee R at Inglis Dam near Dunnellon, FL (Datum = 0.00 feet)
USGS 02313250 Withlacoochee R Bypass Channel NR Inglis Fla (Datum = 0.00 feet)
USGS 02313231 Withlacoochee R BL Inglis Dam NR Dunnellon, Fla. (Datum = 0.00 feet)
Scott et al. (2004) Springs of Florida, Florida Geological Survey Bulletin No. 66 (pages 233, 236):
"Group Description--Rainbow Springs Group forms the Rainbow River, which flows approximately 5.7 miles (9.2 km) south to the tannic Withlacoochee River. Surrounding land has high rolling sand hills with pine forest, agricultural fields and developed areas. Springs, in addition to those at and near the head of the Rainbow River, discharge from numerous limestone crevices and sand boils in the bed of the river and along the banks through the upper 2 miles (3.2 km)."
"Discharge- All discharge rates are measured in ft3/s.
Average 1965 - 1974 763(1) [763 cubic feet per second (cfs)]
Maximum (October 12, 1964) 1230(1) [1,230 cfs]
Minimum (October 3, 1932) 487(1) [487 cfs]
October 23, 2001 634(7) [634 cfs]"
Rosenau et al. (1977) Springs of Florida, Bureau of Geology Bulletin No. 31 Revised (pages 268, 269):
"The temperature of the water in the headwater springs ranges consistently between 23.0 and 24.0 deg. C. (73 and 74 deg. F.)."
"Studies made by the U.S. Geological Survey (Faulkner, 1973) indicate that the flow of Rainbow Springs is derived from local rainfall that infiltrates the aquifer over a catchment area of about 645 sq. mi. distributed mostly north and northeast of the springs."
SILVER SPRINGS and SILVER RIVER
Flow into the OCKLAWAHA RIVER thence to the ST. JOHNS RIVER
The headspring pool of the Silver Springs Group has a usual surface water elevation of about 40 feet above mean sea level (NGVD 1929).
The Silver River begins there then flows east about 5 river miles until its junction with the Ocklawaha River. The Ocklawaha River then flows mostly north some 51 river miles downstream until it empties into the tidal St. Johns River. About 21 river miles of the Ocklawaha River are impounded by the Rodman (Kirkpatrick) Dam as the 13,000 acre (at elevation 20 feet) Lake Ocklawaha a.k.a. Rodman Reservoir or Rodman Pool. Massive amounts of Ocklawaha River basin freshwater are lost to evapo-transpiration in the man-made Lake Ocklawaha--possibly up to 100 cubic feet per second!
OCKLAWAHA RIVER BASIN U.S.G.S. STREAMFLOW GAGES
USGS 02238500 Ocklawaha River at Moss Bluff, FL (Datum = 0.0 feet)
USGS 02239500 Silver Springs near Ocala, FL (Datum = 38.6 feet)
USGS 02239501 Silver River near Ocala, FL
USGS 02240000 Ocklawaha River near Conner, FL (Datum = 31.79 feet)
USGS 02240500 Ocklawaha River at Eureka, FL (Datum = 0.0 feet)
USGS 02243959 Ocklawaha R above Rodman Dam near Orange Springs, FL (Datum = 0.0 feet)
USGS 02243960 Ocklawaha R at Rodman Dam near Orange Springs, FL (Datum = 0.0 feet)
Scott et al. (2004) Springs of Florida, Florida Geological Survey Bulletin No. 66 (pages 244, 245):
"Group Description-- The Silver Springs Group, flowing from numerous vents, forms the headwaters of the Silver River, a major tributary of the Oklawaha River. There are numerous smaller springs in the bed or at the edges of the spring run within about 3,500 ft (1,066.8 m) of the main orifice. The run is usually clear and the bottom at all locations in the springs and run is easily visible. The Silver River flows from its headspring eastward for approximately 5 miles (8 km) through a dense mixed hardwood and cypress swamp to the Oklawaha River. The Oklawaha River flows northward and is a tributary to the St. Johns River. Higher sandy terrain with pine and the Silver Springs community lie to the west of the springs."
"Discharge--Silver Springs Group
October 1932 to September 1974: 820 ft3/s(1) average [820 cubic feet per second (cfs)]
Maximum October 7, 13-17, 20, 1960: 1,290 ft3/s(1) [1,290 cfs]
Minimum May 7, 1957: 539 ft3/s(1) [539 cfs]
November 15, 2001: 556 ft3/s(7) [556 cfs]"
Rosenau et al. (1977) Springs of Florida, Bureau of Geology Bulletin No. 31 Revised (pages 25, 26, 278, 279):
"The flow of Silver Springs is derived from recharge by rainfall within the bounds of the catchment area."
NOTE: An illustration of this Silver Springs catchment area shows its size to be about 54 miles north to south (from near Keystone Heights in Clay County to near Lady Lake in Lake County) but only about 15 miles east to west at its widest point (in Marion County from the west side of the Ocklawaha River to just west of the city of Ocala).
"The temperature of the water a few feet below the surface in the pool ranges consistently between 23.0 and 24.0 deg. C. (73 and 74 deg. F.)."
"Investigations by the U.S. Geological Survey indicate that the flow to the springs in from recharge by local rainfall in a catchment area of 730 sq. mi. that lies mostly north, west, and south of the springs (Faulkner, 1973)."
"Silver Springs as a group has the largest long-term, measured average flow of any freshwater spring group in Florida and possibly in the United States. However, some spring groups along the Florida coast that have little or no discharge records may discharge greater quantities of water."
Knowles, L., Jr. 1996. Estimation of evapotranspiration in the Rainbow Springs and Silver Springs basins in north-central Florida. Water-resources investigations report 96-4024. United States Geological Survey.
Normandeau Associates, Inc. 2011. Restoration plan for the Rainbow Springs and River (June 16, 2011 draft). Prepared By Normandeau Associates, Inc., Gainesville, FL for Ground Water and Springs Protection Section, Florida Department of Environmental Protection, Tallahassee, FL.
Rosenau, J. C.; G. L. Faulkner, C. W. Hendry, Jr.; & R. W. Hull. 1977. Springs of Florida. Bureau of Geology: Bulletin No. 31 Revised, Florida Department of Natural Resources, Tallahassee, FL. 461 pp. Available as a hardcopy.
Scott, T. M. (PG #99); G. H. Means; R. P. Meegan; R. C. Means; S. B. Upchurch; R. E. Copeland; J. Jones; T. Roberts; and A. Willet. 2004. Springs of Florida. Florida Geological Survey: Bulletin No. 66, Florida Department of Environmental Protection, Tallahassee, FL. 677 pp.
REFERENCE AS: Nosca, P. 2015. "Rainbow Springs vs. Silver Springs" webpage report. "Ocklawahaman Paul Nosca reports" website. Paul Nosca, Eureka, FL.