Fall Creek/White River Tunnel Evaluation Study

1. Fall Creek/White River Tunnel Evaluation Study CITY of INDIANAPOLIS DEPARTMENT of PUBLIC WORKS U.S. ARMY CORPS of ENGINEERS Clean Stream Team Advisory Committee Meeting – May 18, 2005 G.E.C., Inc. Black & Veatch Corporation

2. Presentation Overview • Project Team Members • Scope of Tunnel Evaluation Study • How a Deep Tunnel Works • Tunnel Project Screening Criteria • Geology and Hydrogeology • Tunnel Design Considerations • Next Steps & Committee Feedback

3. Project Team Members • Department of Public Works – Engineering • Department of Public Works – Operations • Department of Public Works – Environmental Services • U.S. Army Corps of Engineers – Louisville District • Indianapolis Clean Stream Team (CST) • Department of Parks and Recreation – Greenways • Indianapolis DMD Planning Division • Veolia Water Indianapolis • Indianapolis Water • United Water • Black & Veatch and G.E.C., Inc.

4. Pogues Run Tunnel Shaft Construction Tunnel Project Phases • Current Phase: Preliminary Study • Initial Geotechnical Exploration Program • Facility Planning • Detailed Design • Bid Phase / Contract Award • Construction • (10-15 Year Overall Schedule)

5. Scope of Preliminary Evaluation Study • Project Summary and Description • Construction and Project Considerations (size, length, alignment, staging areas, pumping stations) • Risk Management • Preliminary Geotechnical Reconnaissance • Preliminary Cost and Schedule • Decision Screening • Conclusions and Recommendations

6. Wet Weather Combined Sewer System - How It Works Combined Flow to WWTP and Outfall CSO Outfall Regulator WWTP River To WWTP Combined Sewer SOILS BEDROCK

7. Wet Weather Drop Shafts Deep Tunnel System - How it Works Combined Flow to WWTP and Tunnel CSO Outfall Regulators WWTP Consolidation Sewer River To WWTP Combined Sewer SOILS CSO to Tunnel SHALE CSO to Tunnel Working Shaft Storage Tunnel Deep Tunnel Pump Station to WWTP BEDROCK

8. Primary Decision-Making Criteria • Impacts to Water Supply • Geotechnical Risk • Underground Easement Acquisition • Population Impacts • Environmental Contamination • Tunnel/Sewer Flexibility • Operations & Maintenance • Others

9. Geology and Hydrogeology • Reviewed Available Literature on Regional Geology ~210’ below ground surface ~260’ below ground surface 7.5–10.5 miles

10. Groundwater Monitoring Plan • Goals of the Groundwater Monitoring Plan • Regional Cooperation to Monitor Groundwater Level and Quality before Construction • Develop Predictive Models as Tools • Develop Instrumentation and Control Specifications • Map Geology during Construction • Monitor the Drawdown and Recovery of Groundwater Level

11. Protecting Groundwater and Water Supply • Structural Controls During Construction • Short-Term: Pre-excavation and Cut-off Grouting • Long-Term: Contact Grouting and Permanent Concrete Liner • Operational Controls After Construction • Controlling Exfiltration • Limit Tunnel Fill Level and Duration of Storage • Minimize or Prevent Surges, Backflows and Rapid Pressure Changes

12. Tunnel Shaft Workers Overview of Tunnel Components • Tunnel Size, Length and Diameter • Alignments to Capture CSOs from 43 Outfalls • 27 along Fall Creek, 16 along White River • Working and Retrieval Shafts • Consolidation Sewers/Drop Shafts

13. Tunnel Size, Length and Diameter • Preliminary Sized for 95% (189.5 MG) or 97% (310 MG) Capture of CSO • Three Alternatives Evaluated • West, Central and East • Length from 7.5-10.5 miles • Diameter Varies based on Length and Capture % • Finished Diameters Range from 26 - 35 feet • Expandable Design for 99% (504 MG) Capture • Unprecedented Diameter for Alignments Evaluated (45 feet finished) • Design of “Extension” Shafts for Future Tunnel Expansion

14. Tunnel Alignments Evaluated

15. Consolidation Sewers and Drop Shafts • Sized for 99% CSO Capture • Consolidation Sewers • Used to Group CSO Outfalls • Direct Flows to Tunnel Drop Shafts • Cost Savings over Tunneling • Open-Cut Sewer Construction • Drop Shafts (21 Total) • Transfer CSO from Consolidation Sewers into Tunnel

16. Working Shaft Alternatives • Reilly Site, Southern Avenue, and Bluff Road ~210’ below ground surface ~260’ below ground surface 7.5–10.5 miles

17. Retrieval Shaft Alternatives • Keystone Dam and Sutherland Avenue Sites ~210’ below ground surface ~260’ below ground surface 7.5–10.5 miles

18. Recap:Primary Decision-Making Criteria • Impacts to Water Supply • Geotechnical Risk • Underground Easement Acquisition • Population Impacts • Environmental Contamination • Tunnel/Sewer Flexibility • Operations & Maintenance • Others

19. Decision Screening • Summary of Screening Factor • Results of the Decision Screening Process • Tunnel Alignment Preferred Alternative • West Alignment • Working Shaft Site • Bluff Road • Retrieval Shaft Site • Sutherland Ave. Considerations

20. Recommended Next Steps • Public Meeting on Preliminary Study • Geotechnical Exploration Program • Land Acquisition Study • Environmental Site Assessments • Groundwater Monitoring Plan • Continued Public Outreach and Stakeholder Involvement

21. Proposed Public Meeting Format Presentation Station #3: Wellfields Q&A Station #1: Why Build a Tunnel? Public Seating Station #2: Alt. Tunnel Routes Station #4: Construction Q&A Room Layout

22. Discussion / Q&A