2005 Salt Lake City Annual Meeting (October 16–19, 2005)

Paper No. 6
Presentation Time: 1:30 PM-5:30 PM


DAVIES, Gareth J.1, KINCAID, Todd R.2, HAZLETT, Timothy J.3, LOPER, David4, DEHAN, Rodney5 and WERNER, Christopher4, (1)Tennessee Department of Environment and Conservation, DOE Oversight Office, 761 Emory Valley Road, Oak Ridge, TN 37830, (2)Hazlett-Kincaid Inc, 27 Keystone Av, Reno, NV 89503, (3)Hazlett-Kincaid, Inc, 6753 Thomasville Road, Suite 108-213, Tallahassee, FL 32312, (4)Geophysical Fluid Dynamics Institute, Florida State Univ, Tallahassee, FL 32306-4360, (5)Florida Geol Survey, Gunter Building MS #720, 903 W. Tennessee St, Tallahassee, FL 32304-7700, gareth.davies@tn.gov

Wakulla Spring, in the Woodville Karst Plain (WKP) of northwest Florida, is the third largest spring in the state and possibly the largest single-vent spring in the world. The discharge varies between 0.5 and 50 cubic meters/sec. Florida has over 1,000 first magnitude springs that are treasured recreational locations for water sports, diving, and watching a wide variety of wildlife. The majority of eastern Florida's coastline and the majority of the west side of the peninsular is dominated by carbonate rocks at the surface and a karst landscape with water filled sinkholes, karst windows, sinking streams and springs. Recharge is a combination of mostly swampy, tannic, sinking stream water and good-quality groundwater that moves rapidly through conduits to discharge at springs. Over the past several decades there has been a noticeable decline in water quality at Florida's springs. Wakulla Spring, the “Crown Jewel” of the State Park System, has, over the last several decades, shown increased nitrate levels, algal mat, non-native plant growth, and discharges of larger amounts of dark tannic waters. Other springs in Florida have shown similar changes. More than 60 km of flooded caves have been mapped by divers in the WKP with explored sections connecting to Wakulla Spring. Tracing and in-situ data from cave tunnels have been used to study the flow. Results show that surface water from the swamps and the streets of Tallahassee, as well as the deeper groundwater rapidly discharges through conduits to Wakulla Spring 15 - 20 km away. In fact whatever water recharges the WKP and enters the flooded conduits (regardless of age) discharges rapidly, within a few weeks, at Wakulla and other springs. Innovative modeling has been done using FEFLOW and detailed measurements show a complicated vertical hierarchical flow system. These and other data suggest that if water quality at the springs is to be revived there have to be significant changes made in the way the landscape is managed.