1. AQUIFER STORAGE AND RECOVERY DESIGN CONCEPTS- KEYS TO SUCCESS Thomas M. Missimer, Ph.D. Missimer Groundwater Science, A Schlumberger Company Fort Myers, Florida Thomas M. Missimer, Ph.D. Missimer Groundwater Science, A Schlumberger Company Fort Myers, Florida

2. PURPOSEPURPOSE To assess ASR feasibility methods that should be used for providing assurance in the development of successful ASR projects that meet water resource management goals

3. PROBLEM: WHY DO MANY ASR PROJECTS FAIL TO MEET PRE- PROJECT PLANNING GOALS 1) Goals are set with unrealistic expectations 2) Poor initial selection of the storage aquifer or zone 3) Inadequate aquifer characterization 1) Goals are set with unrealistic expectations 2) Poor initial selection of the storage aquifer or zone 3) Inadequate aquifer characterization

4. PLANNING AN ASR PROJECT Set goals for capacity and recovery percentage Assessment of potential storage aquifers/zones using existing data Assessment of water use from potential storage aquifers Assessment of desired ASR storage capacity Set goals for capacity and recovery percentage Assessment of potential storage aquifers/zones using existing data Assessment of water use from potential storage aquifers Assessment of desired ASR storage capacity

5. PLANNING AN ASR PROJECT Assess potential water quality problems in storage aquifer (i.e. saltwater intrusion, contamination Arsenic) Geochemical assessment of proposed storage water and aquifer water and matrix Economic assessment Preliminary cost projections Assess potential water quality problems in storage aquifer (i.e. saltwater intrusion, contamination Arsenic) Geochemical assessment of proposed storage water and aquifer water and matrix Economic assessment Preliminary cost projections

6. City of Daytona Beach, FL ASR System, Aquifer to Aquifer ASR

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

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

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

10. Types of Tank “Walls” in Useful Storage (Continued) n 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

12. FUNDEMENTAL ASR ISSUES Aquifer Heterogeneity Scaling Aquifer Characterization/Hydraulic Properties ASR Performance Analysis Geochemical Issues Aquifer Heterogeneity Scaling Aquifer Characterization/Hydraulic Properties ASR Performance Analysis Geochemical Issues

13. AQUIFER HETEROGENEITY “ Geology is ubiquitously heterogeneous, exhibiting both discrete and continuous spatial variations on a multiplicity of scales. It is therefore natural to expect that hydrogeologic and other geophysical variables would due likewise.” Neuman and Federico, 2003 “ Geology is ubiquitously heterogeneous, exhibiting both discrete and continuous spatial variations on a multiplicity of scales. It is therefore natural to expect that hydrogeologic and other geophysical variables would due likewise.” Neuman and Federico, 2003

14. ASR CONCEPTS: “THE BUBBLE” ASR WELL CONFINEMENT

15. ASR CONCEPTS: THE REAL WORLD ASR WELL CONFINEMENT FRESH WATER MIXING ZONE BRACKISH WATER CONFINEMENT

16. ASR WELL

18. HOW HETEROGENEOUS ARE AQUIFERS? Siliciclastic aquifers-kh/kv ranges from 5 to 12 in clean beach sands, kh/kv ranges from 10 to 100 in alluvial sands, fluvial depsoits, and glacial deposits Carbonate aquifers-typical range of Kh/kv is 20 to 200 Fractured rock aquifers-typical range is 0.5 to 100 Siliciclastic aquifers-kh/kv ranges from 5 to 12 in clean beach sands, kh/kv ranges from 10 to 100 in alluvial sands, fluvial depsoits, and glacial deposits Carbonate aquifers-typical range of Kh/kv is 20 to 200 Fractured rock aquifers-typical range is 0.5 to 100

20. THE SCALE FACTOR 1.Effects plume geometry 2.Effects recovery 3.Extremely important in carbonate aquifers 4.Extremely important in alluvial aquifers containing channel deposits 1.Effects plume geometry 2.Effects recovery 3.Extremely important in carbonate aquifers 4.Extremely important in alluvial aquifers containing channel deposits

21. THE SCALE FACTOR: TESTING AND PROJECT SIZE 1.The larger the scale of testing – the larger the hydraulic conductivity measured. 2.The larger the scale of an ASR project – the larger the influence area. 1.The larger the scale of testing – the larger the hydraulic conductivity measured. 2.The larger the scale of an ASR project – the larger the influence area.

23. AQUIFER CHARACTERIZTION Phased Field Investigations Go/No Go Decision Process Test Drilling -Hydraulic Rotary -Coring -Reverse Circulation Drilling -Reverse-air Drilling Phased Field Investigations Go/No Go Decision Process Test Drilling -Hydraulic Rotary -Coring -Reverse Circulation Drilling -Reverse-air Drilling

24. AQUIFER CHARACTERIZATION Geophysical logging Preliminary Modeling ASR Test Well and Monitoring well Construction Preliminary Pumping Tests Injection/Recovery Cycle Testing – Scale Issue Geophysical logging Preliminary Modeling ASR Test Well and Monitoring well Construction Preliminary Pumping Tests Injection/Recovery Cycle Testing – Scale Issue

25. AQUIFER CHARACTERIZATION Geochemical Testing Water Quality Interactions/Mixing Analysis Aquifer Matrix Interaction/Leaching Tests Aquifer Performance Modeling Geochemical Testing Water Quality Interactions/Mixing Analysis Aquifer Matrix Interaction/Leaching Tests Aquifer Performance Modeling

26. ASR MODELING EXAMPLE SEAWAT. Three-dimensional, variable- density, transient groundwater flow code, developed by combining MODFLOW and MT3DMS programs. Model based on hydraulic parameters of an existing operational ASR system (Collier County Manatee Road). Model scenario is based on reasonable operational mode for a utility system. SEAWAT. Three-dimensional, variable- density, transient groundwater flow code, developed by combining MODFLOW and MT3DMS programs. Model based on hydraulic parameters of an existing operational ASR system (Collier County Manatee Road). Model scenario is based on reasonable operational mode for a utility system.

27. BASE MODEL 121 rows and columns. 50 ft spacing (x,y). T = 18,000 ft 2 /day. SC = 1 X 10 -4. Leakance (upper and lower) = 4.7 X 10 -5 day -1. Dispersivity = 30 ft. Native water = 5,000 mg/L TDS. Recharge water = 200 mg/L TDS. 121 rows and columns. 50 ft spacing (x,y). T = 18,000 ft 2 /day. SC = 1 X 10 -4. Leakance (upper and lower) = 4.7 X 10 -5 day -1. Dispersivity = 30 ft. Native water = 5,000 mg/L TDS. Recharge water = 200 mg/L TDS.

28. MODELING ASR RECOVERY EFFICIENCY

29. AQUIFER SYSTEM CONSIDERATIONS Geology controls reservoir type and behavior Carbonate aquifer systems Siliciclastic aquifer systems Fluvial Systems Alluvial Systems Marine Systems Fractured rock aquifer systems Geology controls reservoir type and behavior Carbonate aquifer systems Siliciclastic aquifer systems Fluvial Systems Alluvial Systems Marine Systems Fractured rock aquifer systems

30. Confining Beds Vertical Pipe Preferred Flow Corridor Aquifer ASR WELL

31. CARBONATE AQUIFER SYSTEMS

32. ALLUVIAL AQUIFER SYSTEMS

33. CONCLUSIONSCONCLUSIONS Proper planning is a critical factor in ASR system design Hydrogeology of an aquifer effects its potential use for ASR The scale of a test program affects the accuracy of projected ASR system efficiency Proper planning is a critical factor in ASR system design Hydrogeology of an aquifer effects its potential use for ASR The scale of a test program affects the accuracy of projected ASR system efficiency

34. CONCLUSIONSCONCLUSIONS The key to developing a successful ASR project is the aquifer characterization and determination of the aquifer reservoir properties. Insufficient aquifer hydraulic assessment leads to unsuccessful ASR projects.

35. Hillsborough Co., FL ASR Failure Due to Lack of Aquifer Characterization

36. CONCLUSIONSCONCLUSIONS The quality of water in the storage zone is another critical factor in determining ASR system efficiency. The higher the difference between the salinity of the storage aquifer and the injected water, the lower the recovery rate. Trace metals can also create operating issues.