Update on the Floridan Aquifer System in SFWMD

1. Update on the Floridan Aquifer System in SFWMD Peter J. Kwiatkowski, P.G., Director Resource Evaluation Division, Water Supply Dept. Water Resources Advisory Committee Meeting West Palm Beach, Florida February 8, 2007

2. Lake Okeechobee West Palm Beach Labelle Ft. Myers WEST EAST 0 100 Biscayne Water Table Aquifer Aquifer 300 Lower Tamiami Aquifer Sandstone Aquifer 500 Mid Hawthorn Aquifer Hawthorn Confining Zone 700 Upper Floridan Aquifer 900 Middle Confining Unit 1100 1300 Middle Floridan Aquifer Middle Confining Unit 1500 Lower Floridan Producing Zone 1 1700 Lower Confining Unit Lower Confining Unit 1900 Lower Confining Unit 2100 Boulder Zone 3000 2300 Generalized Aquifer System Map of South Florida

3. Aquifer & Relative Yields in South Florida Aquifer Yield Depth (ft bls) Upper Floridan Moderate 800 to 1,500 Boulder Zone Very High 2,800 to 3,500 Biscayne Aquifer Very High 0 to 200 Surficial Aquifer Low 0 to 100 Tamiami Aquifer Low to Moderate 100 to 400

4. General Characterization of the Floridan Aquifer System • Recharge area in Central Florida • Confined in South Florida by several hundred feet of relatively impermeable sediments (Hawthorn Group) – isolated from Biscayne aquifer • Lower portion (Boulder Zone) used to dispose of treated effluent from wastewater treatment plants and concentrate from reverse osmosis facilities • Upper portions of Floridan aquifer system used for brackish (slightly saline) water supply (e.g., Town of Jupiter) since late 1980s • Formations extend offshore at depth (saline water) • Artesian Head – 20 to 30 feet above land surface

5. Geographic Differences of Floridan Aquifer System • Recharge Area in Central Florida • Confined Aquifer in South Florida – less water released from storage, greater drawdowns (USGS Circular 1278) (From USGS Circular 1278)

6. Floridan Aquifer Demands (2000) (USGS Circular 1278) Largest Public Water Suppliers (> 20 MGD)

7. Growth in Floridan Aquifer System Demands Total Demand from the Floridan Aquifer System from 1950 to 2000 (USGS Circular 1278)

8. Broward Palm Beach Miami-Dade Monroe FloridanAquifer LEC Projected Demands for Water Supply and FAS MGD

9. Approved Alternative Water Supply Projects FY07

10. Proposed Aquifer Storage and Recovery (ASR) Areas, Comprehensive Everglades Restoration Plan (CERP), (USACE, 1999) Lake Okeechobee Caloosahatchee Basin L-8 Canal C-51 Canal Central Palm Beach County Site# ASR Wells Lake Okeechobee 200 Caloosahatchee 44 L-8 Basin 10 C-51 Basin 34 Central PBC 15 Hillsboro 30 TOTAL 333 Hillsboro

11. General Characterization of the Floridan Aquifer System • Upper and Middle Floridan Aquifers can be used for both Aquifer Storage and Recovery and RO source water • Brackish quality requires membrane treatment to meet drinking water standards • Relatively stable water quality seasonally, but geographically variable • Some pumping wells become saltier (upconing of more saline water from below or laterally along coast)

12. Comparison to Biscayne Aquifer • Similarities • Variable well yields and water quality within wellfields • May require additional testing initially • Differences • Biscayne aquifer – more data, greater understanding • Biscayne aquifer recharged locally through rainfall, canals, Everglades seepage • Biscayne aquifer subject to contamination • Biscayne aquifer – much more likely to have water shortage restrictions imposed • Potential conflicting uses (RO vs. ASR)

13. Engineering Considerations • Greater Drawdowns • Increased energy costs associated with lifting water via pumps • Adjacent user effects • Potential for decline in water quality over time • Membrane design and periodic replacement • Blending with Biscayne water • Membrane Treatment • Estimated 125% of raw water to meet treated water demands • Concentrate disposal via deep injection wells

14. SFWMD Initiatives • 15 years ago to Present • Installed test well pairs in data gap areas (e.g., rural portions of peninsula) for long-term water supply planning • Conducted aquifer tests to obtain aquifer parameters at these sites • Installed data loggers onto existing and newly installed wells to obtain long-term water level data • 7 years ago to Present • Installed test and monitor wells as part of Aquifer Storage and Recovery (ASR) program for Everglades Restoration

15. SFWMD Floridan Well Network

16. SFWMD Initiatives (cont’d) • 2 years ago to Present • Obtain data from wells installed by utilities under Alternative Water Supply Program • Standardize data input for database purposes • Recruit groundwater data steward to provide quality assurance/quality control function for existing and future data

17. Models Developed • Lower West Coast Floridan • East Central Florida Transient (ECFT) Model • finalizing peer review process now • East Coast Floridan • Contract to be awarded to incorporate Upper East Coast (UEC) area into existing Lower East Coast (LEC) Floridan Model • Contract calls for recalibration with newly acquired data

18. Modeling Issues • Brackish quality of Floridan aquifer and saltwater boundary along the coast requires density-dependent modeling approach • More data intensive • Less data available • Greater uncertainty

19. Conclusions • Floridan aquifer system should be able to meet projected demands identified in LEC Plan • Greater Uncertainty • Initial water quality • Changes in water quality over time • Drawdown effects • Costs will be higher than traditional sources • Better understanding of regulatory framework for reclaimed water, ASR, and changes to C&SF project will likely result in reduced, projected Floridan demands