Land use changes and groundwater quality in Florida

Land use changes around 26 karstic cave–spring systems in Florida were evaluated using geographic information system. Located in the unconfined or semiconfined zones of the Floridan aquifer, some of the cave–spring systems are directly connected to the surficial land use processes by sinking streams, whereas others receiving diffuse recharge are still vulnerable to contamination due to a thin sandy cover overlying the aquifer. Comparison of nitrate-producing land use practices between 2004 and 2013–2014 shows increasing risks of groundwater contamination in the Floridan aquifer. Proliferation of septic systems and wastewater treatment sites due to growing residential areas, increased use of fertilizers for farming and landscaping stand out as major causes of nitrate overload in the both surface and groundwater.