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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. Presentation Overview. Project Team Members - PowerPoint PPT Presentation
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1
Fall Creek/White River Tunnel
Evaluation Study
CITY of INDIANAPOLIS DEPARTMENT of PUBLIC WORKSU.S. ARMY CORPS of ENGINEERS
G.E.C., Inc.Black & Veatch Corporation
Clean Stream Team Advisory Committee Meeting – May 18, 2005
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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.
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Current Phase: Preliminary Study
Initial Geotechnical Exploration Program
Facility Planning
Detailed Design
Bid Phase / Contract Award
Construction
(10-15 Year Overall Schedule)
Tunnel Project Phases
Pogues Run Tunnel Shaft Construction
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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
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Combined Sewer System - How It Works
River
CSO OutfallRegulator
WetWeather
Combined SewerTo WWTP
WWTP
Combined Flow to WWTP
and Outfall
SOILS
BEDROCK
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Deep Tunnel System - How it Works
CSO to Tunnel
River
CSO Outfall
Storage Tunnel
Drop Shafts
Consolidation Sewer
Regulators
WetWeather
Deep Tunnel Pump Station to WWTP
Working Shaft
Combined SewerTo WWTP
WWTP
CSO to Tunnel
Combined Flow to
WWTP and Tunnel
BEDROCK
SHALE
SOILS
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Impacts to Water Supply
Geotechnical Risk
Underground Easement Acquisition
Population Impacts
Environmental Contamination
Tunnel/Sewer Flexibility
Operations & Maintenance
Others
Primary Decision-Making Criteria
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~260’below
groundsurface
Geology and Hydrogeology
Reviewed Available Literature on Regional Geology
7.5–10.5 miles
~210’below
groundsurface
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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
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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
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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
Overview of Tunnel Components
Tunnel Shaft Workers
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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
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Tunnel Alignments Evaluated
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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
Consolidation Sewers and Drop Shafts
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~260’below
groundsurface
7.5–10.5 miles
~210’below
groundsurface
Working Shaft Alternatives
Reilly Site, Southern Avenue, and Bluff Road
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~260’below
groundsurface
Retrieval Shaft Alternatives
7.5–10.5 miles
~210’below
groundsurface
Keystone Dam and Sutherland Avenue Sites
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Impacts to Water Supply
Geotechnical Risk
Underground Easement Acquisition
Population Impacts
Environmental Contamination
Tunnel/Sewer Flexibility
Operations & Maintenance
Others
Recap:Primary Decision-Making Criteria
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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.
Decision Screening
Geotechnical Risk
Impacts to Water Supply
Underground Easement Acquisition
Population Impacts
Environmental Contamination Risk
Tunnel/Sewer Flexibility
Others
0.0
0.1
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0.7
0.8
0.0
0.1
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East Alignment West Alignment Central Alignment
Considerations
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Public Meeting on Preliminary Study Geotechnical Exploration Program Land Acquisition Study Environmental Site Assessments Groundwater Monitoring Plan Continued Public Outreach and Stakeholder
Involvement
Recommended Next Steps
21
Proposed Public Meeting Format
Room Layout
Presentation
Public Seating
Station #1: Why Build a Tunnel?
Station #2: Alt. Tunnel Routes
Station #4: Construction Q&A
Station #3: Wellfields Q&A
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Discussion / Q&A