Equus Beds ASR Program – Wichita’s Future Water Supply

1. Equus Beds ASR Program – Wichita’s Future Water Supply September 6, 2012

2. Wichita Public Works & Utilities • 186 mi2 Service Area • 425,000+ Served • 128,905 Residential Customers • 13,291 Commercial Customers • 160 MGD Lime Softening Plant • Average Day Demand 60 MGD

3. Wichita Water Utilities Sources of Water Equus Beds Well Field – 1940s+55 Wells – 78 MGD Burrton Wichita Well Field Arkansas River Cheney Reservoir – 1965 80MGD Little Arkansas River Local Well Field 19 Wells – 34 MGD Bentley Reserve Well Field Cheney Reservoir Local Well Field Bentley Well Field6 Wells – 10 MGD Wichita

4. Equus Beds Aquifer • 1,400 square miles • 4 Counties • 2,000 Non-Domestic Water Wells • 157,000 acre-feet Withdrawn Annually

5. Projected Water Supply Demands Average Day Demand Projections 250 Peak Day Demand Projections 200 150 Average Day Capacity Million Gallons per Day 100 Max Day Capacity 50 0 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050 YEAR

6. Integrated Local Water Supply Plan (ILWS Plan) • Approved 1993 • Meet 2050 Water Demands • Principle Component 100 MGD ASR Program

7. Equus Beds – Water Level Decline • Since 1940 agricultural and municipal pumping created a depression • 65 billion gallons available for storage (to return to 1940 water levels) More than 30 feet of water-level decline since 1940

8. Equus Beds – Chloride Migration • Studies demonstrate chloride will migrate into the well field by 2050 • Chlorides will exceed 250 ppm

9. Decline in Storage Volume

10. ASR A Win-Win Project • Reliable & Sustainable Water Supply Source through 2050 • Water Quality Protected from Salt Water Contamination • No Requirements to Curtail Irrigation • Irrigators Have Lower Pumping Costs • Improves Low Flows in Little Ark. River • Less Land Required

11. Challenges to ASR Project • 1st ASR Project in Kansas • No Regulations in Place to Administer • No Proof that Water can be Diverted from River by Wells • No Regulations in Place to Administer Bank Storage Wells • No Documentation that ASR would not Contaminate Shared Aquifer • Poor Image of City in Project Area

12. Scale of ASR Program • Ultimate Capacity to Recharge & Recover 100 MGD • 80 mi2 area • Recharge Facilities at Build-out • 97 ASR Wells • 2 Recharge Basins • ASR Wells • Average Depth ~ 200 ft • Average Injection Rate ~ 1 MGD • 134 Monitoring Wells

13. Source of Recharge Water • Surface Water can only be diverted at Above Base Flow Conditions • Expect to Recharge 120 days/year • Spring & Early Fall • Little Arkansas River • High Turbidity • Varies from 8 - 2000 NTUs • High Atrazine Concentration • Varies from >1 – 50 mg/L

14. Typical Storm Event Minimum Flowrate for Diversion

15. ASR Program Schematic

16. Recharge Basin • Area • 4.5 acres • Recharge Rate • ~ 1.5 in/day

17. Typical ASR Recharge Well Recharge Tubes (3-4 per well)

19. ASR Phase I • Location selected to prevent migration of chlorides into the Equus Beds • Constructed to establish a hydraulic barrier Phase I Phase I City Wells City Wells

20. ASR Phase I • Recharge & Recovery Capacity of 10 MGD • ASR Facilities • 7 MGD River Intake • SWTP (7 MGD) • 15 miles of pipeline • 3 Diversion Wells • 4 ASR Wells • 2 Recharge Basins

21. ASR Phase I • Award Winning Project • Has established the hydraulic barrier

22. ASR Phase II • Recharge & Recovery Capacity of 30 MGD • ASR Facilities • River Intake (60 MGD, Equipped for 30 MGD) • SWTP (30 MGD) • 31 ASR Wells • Recharge Basin (~ 7 MGD) • 31 miles of Pipelines • Vital Statistics • 950 Sheets of Design • 43 Permits Obtained • 51 Easements Acquired

23. ASR Phase II • ASR Phase II SWTP Treatment Process • Pre-Sedimentation & Ultrafiltration Membranes to remove suspended solids • Advanced Oxidation Processes (AOP) for Virus Inactivation & Destruction of Atrazine (and other pesticides)

24. Intake Site

25. Intake Structure Model 1:5 Scale

26. ASR Phase II SWTP

27. Regulatory Controls • First ASR project in Kansas – NO regulations existed to administer • Project includes restrictions on flow conditions in the river. • Class V permit from KDHE controls water quality to wells and basins. • Establishment of index well network. • Installation of numerous monitoring wells near diversion wells and recharge sites.

28. Diversion Wells • Appropriations require at least 56 cfs in the river during irrigation season • Drawdown less than 10 feet 660 feet from well • Recovery to regional water level in less than 7 days • No impairment to other groundwater users

30. ASR Phase II – Geochemical Evaluation • Evaluate Mixing of Surface Water, Groundwater and Equus Beds Aquifer Matrix • Preliminary Predictions: • Pyrite (if present) within the aquifer matrix, may oxidize releasing arsenic • Iron will also precipitate and form a rust coating on matrix • Arsenic is absorbed onto rust

31. ASR Phase II – Geochemical Evaluation: Pilot Study Filters

32. Recharge Quantity • 2006 – No recharge because of low flows in river. • 2007- 369 million gallons recharged. • 2008 – 319 million gallons recharged • 2009 – 170 million gallons recharged • 2010 – 89 million gallons recharged • 2011 – No recharge – low flow and construction issues • 2012 – 33 million recharged to date To date – 978 million gallons (over 3,000 AF) has been recharged.

33. ASR Phases III & IV • Recharge & Recovery Capacity of 60 MGD • ASR Facilities • To Be Determined • Likely to consist of Diversion Wells and/or additional diversion capacity at Phase II River Intake • Possible expansion of Phase II SWTP

34. Questions?