1. Assessment of Aquifers for ASR Use: Hydrogeology Does Matter!
Thomas M. Missimer, Ph.D., P.G.
Robert G. Maliva, Ph.D.
Weixing Guo, Ph.D.
CDM Missimer
Fort Myers, Florida

2. Purpose
To discuss fundamental principles involving the successful development of ASR systems in carbonate aquifers.

3. The Concept of Useful Storage in ASR Systems
The tank must have walls.

4. Useful Storage Concepts
Gain of actual storage
Reduction of dry season adverse impacts
Movement of saline/freshwater interface seaward
Recovery of water with no treatment

5. Types of Tank “Walls” in Useful Storage
Saline-water aquifers
Provide “real” storage for freshwater injection of all types

6. Types of Tank “Walls” in Useful Storage (Continued)
Fresh-water aquifers
Provides no storage, except for potable water when it can be recovered without treatment
Injection of stormwater or reclaimed water is useful if it contains or eliminates saline- water intrusion

8. Effects of Aquifer Anisotropy on ASR Plume Geometry
Fact
“Hydraulic conductivity is lognormally distributed in carbonate sediments.”

10. Causes of Aquifer Anisotropy
Primary Depositional Features
Bedding
Sequence stratigraphy
Diagenesis
Dissolution (vertical and horizontal)
Change in mineralogy (dolomitization)

11. Effects of Bedding
kx/k2 = 1
kx/k2 = 100

14. Effects of Sequence Stratigraphy

17. Sandy Molluscan Wackestone
Subfacies 4
Sandy Molluscan Wackestone
Diagnostic Characteristics
Quartz sand
Carbonate mud matrix
Mollusks (open marine)
Corals
Environmental Interpretation
Inner ramp
Green algae
Burrows
Lag deposits

19. W
1 mm

20. W
1 mm

22. Scaling Factor in Measurement of Aquifer Hydraulic Conductivity
Up to 9 orders of magnitude difference in calculated hydraulic conductivity

24. Conclusions
In carbonate aquifers, hydraulic conductivity is lognormally distributed.
ASR plume geometry is greatly affected by the distribution of hydraulic conductivity within all carbonate aquifers.

25. Conclusions (Continued)
On a regional scale, flow through carbonate aquifers does not conform to typical transmissivity or hydraulic conductivity contour maps, but moves more quickly (e.g. Floridan Aquifer System). This greatly affects the design of large-scale projects, such as the Everglades ASR project.

26. Conclusions (Continued)
Anisotropic distribution of hydraulic conductivity requires a higher degree of hydrogeologic evaluation in the early stages of ASR system design.
Hydraulic conductivity in carbonate aquifers is not randomly distributed and models can be developed to predict plume geometry by placing emphasis on quality hydrogeologic investigations of potential ASR sites.