INNOVATIVE INVESTIGATIVE APPROACH TO ASSESSING THE CULTURALLY-INDUCED WATER-QUALITY CHANGES IN WAKULLA AND MANATEE SPRINGS, FLORIDA

Florida is one of the fastest growing states in the country. Karst terrain predominates in much Florida where the carbonate Floridan aquifer system is at or near the land surface. Geologists have inventoried more than 700 springs in Florida. A trend of declining quality of water emanating from many of Florida’s springs was recognized. With funding from the Florida Springs Initiative, two first magnitude springs, Wakulla and Manatee, were selected for a unique investigative approach to water-chemistry provenance. Both springs have on-going water-quality sampling programs. The springsheds of these springs are being delineated based on extensive water-level data, chemical and physical parameters. Both springs have extensive underwater cave systems with multiple conduits. Individual conduits have different water quality indicating different source areas. As such, cultural activities may affect the water quality in one portion of the system but not another. Through water-quality monitoring and springshed delineation, the effects of cultural activities on groundwater and the springs can be better understood.

Historically, water samples gathered from individual conduits had to be taken by cave divers, a time-intensive and dangerous undertaking. Discussions between scientists and managers concluded that drilling wells into selected conduits at Wakulla and Manatee Springs would provide a new and innovative way to access the conduits for periodic sampling and monitoring instrument placement. Wells were drilled into three conduits at Manatee Springs during May and June 2003. Placement of the wells was accomplished by divers placing an oriented radio beacon in a conduit and a surface receiver pinpointing the vertical location. The FGS drill rig cored each hole approximately 23 meters deep. Wells up to 100 meters deep will be drilled into the conduits at Wakulla Springs in July and August 2003. Probes to continuously measure flow, temperature, nitrate and other parameters will be placed in the conduits by divers and will be connected to the surface through the wellbore. Water-quality samples can now be obtained to study short-term responses to storm events and for comparison to long-term data sets. This data will allow geologists to assess the degradation of Florida’s springs and assist the State in developing BMPs.