Hydrogeochemistry

Evaluating surface water and groundwater chemistry is critical to ensure good quality drinking water. Research in this area includes water-rock interaction and metals mobilization during Aquifer Storage and Recovery (ASR); Florida springs and aquifer system ambient geochemical data collection and interpretation; and water quality trends analysis. See below for more detailed information regarding Aquifer Storage and Recovery in Florida.

Florida Aquifer Storage and Recovery (ASR) and Aquifer Recharge (AR)

Direct injection of treated domestic wastewater and/or reclaimed water into confined or semi-confined permeable formations for later recovery and use, a technique known as Aquifer Storage and Recover (ASR), is becoming a widely accepted practice for water resources management. Multiple ASR facilities are either under construction or are in operation in Florida to help meet increasing demands for drinking water, agricultural production and environmental restoration. Additional aquifer recharge (AR) sites are operational throughout the state where withdrawal and saltwater intrusion have increased over the past several years.

Biogeochemical reactions between native groundwater and recharge water can alter the groundwater chemistry and can create other problems such as mineral precipitation and mobilization of trace elements (e.g. arsenic). Therefore, better understanding the water quality changes during ASR will assist in mitigating any potential adverse reactions and render ASR a more useful water management tool for guiding regulatory policy.

Over the past 20 years, the Florida Geological Survey has worked with the DEP Underground Injection Control Program (Division of Water Management) to investigate:

• Chemical (including isotopic) variability existing within ground water and the carbonates of the Floridan Aquifer System.
• Variability that may result in site-specific geochemical processes affecting ASR/AR wells and water quality.
• Capacity for injectable to cause the release of trace metals into the recharged (and eventually recovered) waters.
• Design of recharge-storage-recovery cycle tests and the location of monitor wells as important aspects of understanding these geochemical processes.

The most recent study, review of selected Florida Aquifer Storage and Recovery (ASR) sites and their geochemical characteristics, was completed and published in 2015 as FGS Report of Investigation 112.

Multiple FGS contract deliverables related to ASR and aquifer research can be found on Contract and Grant Deliverables.