FDEP Report (Project AT#024)

The Florida Department of Environmental Protection (DEP) funded grant AT024 that provided resources to Sunfish Inc and the University of South Florida (USF) to comprehensively study the cave system associated with Lafayette Blue Springs (LBS) which drains the highly productive, karstic Floridan Aquifer System (FAS). The project consisted of two primary components. The first was to use the Sunfish Autonomous Underwater Vehicle (AUV) to map the location, geometry, and water quality of the cave system that supplies water to LBS. The conduit location information can be used to understand land use connections that contribute to water quality changes while the water quality and conduit geometry can be used in groundwater models to understand groundwater flow and solute transport dynamics. The second component was led by USF and utilized the high-resolution nitrate, specific conductivity, and temperature data collected by Sunfish AUV to identify areas of the cave system where more detailed geochemistry would be collected by scientific divers. The detailed geochemistry was used to more precisely inform pollution sources and identify controls on water quality variability across the LBS cave system.
The physical and geochemical data collected at LBS for this project provides results that can be directly used in water resource decision making and the development of detailed groundwater flow and solute transport models. The water quality mapping by SUNFISH AUV, water quality sampling from scientific diving, and geochemical analyses provided insight on the controls on nitrate variability within the cave system and subsequent geochemical analysis identified markers on the landscape contributing to groundwater contamination. Furthermore, the Sun SUNFISH AUV water quality mapping highlights the
utility in high spatial resolution water quality data collection that cannot be captured by discrete sampling from scientific diving alone. The physical conduit data can be used to not only understand land use influences on LBS, but also to develop a groundwater model to identify contamination storage and transport timescales, which is much needed for this impaired system. The groundwater model can also be used to test remediation strategies including turning off the nitrate source and quantifying timescales to improve water quality at LBS. Coupled robotic technology and scientific diving efforts to explore cave systems in the FAS can more precisely inform management of targeted land use remediation, and these results collectively highlight the need to know the location and geochemical characteristics of the cave systems that support critical spring ecosystems