The Springs Basin Story

Ichetucknee Springs Basin

Yesterday's rain is tomorrow's spring water.

Do you know why?

• The clear, blue waters of the Ichetucknee River are turning green?

• Floating mats of noxious algae are increasing in the Ichetucknee Spring Runs?

• Algae is coating and smothering the native eelgrass?

• Some swimmers and tubers are experiencing allergic reactions?

• The abundant populations of crawfish and musk turtles are disappearing.

The answers lie in the Ichetucknee Springs Basin.

The Ichetucknee Springs Basin is approximately 300 square miles located mostly in Columbia County. Small portions of the basin overlap into Suwannee, Baker and Union Counties. Ichetucknee Springs drains the basin (aquifer) and rainfall refills (recharges) the basin. During droughts, the water level in the aquifer drops and spring flow diminishes. During periods of heavy rainfall, the level of the aquifer rises and spring flow increases. Spring basin boundaries also migrate inward and outward somewhat as the level of the aquifer expands and contracts. The rate of groundwater flow through the porous limestone in most parts of the basin is slow, likely taking decades to reach Ichetucknee Springs.

The creeks and lakes in the basin drain through sinkholes into conduits in the limestone. These conduits are spaces within the limestone where the rock has been dissolved away and through which groundwater flows down gradient (southwesterly) to Ichetucknee Springs. In the southern part of the basin, groundwater flow is faster, especially through the caves. The caves are like superhighways that rapidly transport groundwater several miles to the springs. Yesterday's rain is tomorrow's spring water.

Sinkholes occur in Alligator Lake and in Lake Montgomery. In 1837, John Lee Williams wrote Alligator Lake drains into a sinkhole. Alligator Lake periodically drains through sinks into conduits in the aquifer. The lake's water has been found in monitoring wells three miles to the southwest near Cannon Sink. Just as the Okefenokee Swamp is the headwaters of the Suwannee River, Alligator Lake is the headwaters of the Ichetucknee River.

The Cody Scarp is a geological divide that separates lands to the north that are covered by a continuous layer of clay and lands to the south that lack the continuous clay layer. The clay layer north of the scarp protects groundwater somewhat from pollution; whereas, the absence of the clay layer south of the scarp enables pollutants to easily migrate through the soil to the groundwater.

Cannon, Clayhole and Rose Creeks are tributaries of the Ichetucknee River that was once a continuous surface river from Lake City to the Santa Fe River as shown in an 1829 map. Since then, sections of the river have been captured by sinkholes and are now flowing underground through caves. Today, the dry riverbed is called the Ichetucknee Trace. Under normal conditions, the creeks drain into the sinks and the water flows through the caves to the springs where the surface river reforms.

When the trace is flooded during hurricanes or other periods of heavy rain, the sinkholes and cave system cannot immediately drain the floodwater downstream to Ichetucknee Springs. Ten inches of rain during Hurricane Frances in September 2004 filled much of the trace with water and flooded numerous houses in the trace. During a future hurricane, the amount of rainfall will be sufficient to flood the entire trace and you will be able to motorboat the Ichetucknee River from Alligator Lake to the Santa Fe River.

Cannon Creek conducts surface water south from the urban development of Lake City and Clayhole and Rose Creeks flow west draining agricultural and other rural lands to the east. After these creeks cross the Cody Scarp, they flow underground through sinkholes into the conduits connected to Ichetucknee Springs. Separate dye trace studies have confirmed the connection of Rose Sink to the springs. A dye trace study has also confirmed the connection of Black and Dyal Sinks, located in Clayhole Creek, with Rose Sink and the springs. The sections of the trace between Clayhole Creek and Rose Sink and from Rose Sink to the springs are present day land bridges. No other creeks occur between Rose Sink and the springs which demonstrates that the clay layer is absent and rain flows directly through the soil to the aquifer. All of these geological features: Alligator Lake, Cannon, Clayhole, and Rose Sinks, and Ichetucknee Springs are probably aligned along a major northeast/southwest fracture in the limestone.

Cave divers are exploring this fracture by entering the cave system at Rose Sink. They have extended their exploration approximately one mile downstream beneath the Ichetucknee Trace at a depth of 140 feet. In time, they may travel as far as the limerock mines and beyond.