Deep Tunnel, Shallow Pipe - How the City of Hamilton, OH plans to save millions on SSO control. Glenn Weist, P.E.

Transcription

1 Deep Tunnel, Shallow Pipe - How the City of Hamilton, OH plans to save millions on SSO control Glenn Weist, P.E. Columbus, Ohio May 10, 2012

2 Agenda Background Project Description Regulatory Synopsis Stakeholder Engagement Tunnel and Pipe Designs Construction Challenges Scope Change Summary

3 Background Founded in ,000 Economically Challenged Provides water, sewer, gas and electric utilities First Consent Order from the State in 1991

4 Project Description SSO pipe into 24 Siphon SSO , 15 and 12 into 2x16 Siphon Existing 60 Interceptor Dual barrels, single structure OhioEPA Modified Consent Order Capture the 10 year 4 hour storm event Convey to the WRF Great Miami River Buried Valley Aquifer WRF

5 Regulatory Synopsis 1991 first State Consent Order, 26 SSO locations I/I studies, improvements, and O&M reduced the locations to Revisions to Consent Order 2002 Collection System metering and model building 2007 Modified Consent Order Remaining 2 SSOs (027 and 037) Flow limited by Siphon Phase 1 Capture and Convey Phase 2 Treatment Increased Flow 2007 System Evaluation and Capacity Analysis Plan Tunnel recommendation 2009 Prefeasibility Study Deep Tunnel Storage - $45M 2010 Sewer Feasibility Study - $25M 2014 OCtober - construction must be complete

6 Stakeholder Engagement City of Hamilton Great Miami River is a Recreation Destination Miami Conservancy District In response to the Great Flood of 1913 Ground Water Consortium Public and Private partnership OhioEPA Director s desire is timely compliance USACOE CSXT Sit at the same table early in project

7 Deep Tunnel Design Black River limestone 500 to 700 feet Propane storage since the 1960s Watertight and strong Unconfined Compression Test up to 28,000 psi Drop Shaft small foot print - <2 acres Pump Station required Feasibility Study Cost Estimate - $45M

8 Shallow Pipe Design 16,000 feet 60, 2500 feet of 48 Convey and Store All Gravity Real Time Control Inside conservancy property 5 Private Easements 2 River Crossings Limited Relocation of Utilities Flow limit at WRF = 62 MGD Feasibility Study Cost Estimate - $25M

9 Pipe Design Performance Based Water tight design Infiltration and Exfiltration Stiffness 72 psi on flexible pipe MH material matching PCCP, AWWA C-301, with ConShield Fiberglass, AWWA C-950 Centrifugally Cast Fiberglass Mortar Pipe Filament Wound Competitive Pricing Desired Invited to meet with the City

10 PCCP Advantage Excellent Water tightness Robust Established design Initial Bedding only Custom Fittings Lower buoyancy Weakness Steel could corrode if exposed Price could fluctuate with steel price Heavy 60 /20 /25k# 20 laying length

11 Fiberglass - CCFRPM Advantage Excellent Water tightness Lower weight 60 /20 /5k# Superior corrosion OD held true Possibly higher erosion resistance 40 laying length Weakness Bedding is crucial Proper storage for shape Exposure to sunlight Outer coupling Concrete collars required for buoyancy

12 Fiberglass Filament Wound Advantage Excellent Water tightness Lower weight 60 /20 /5k# Superior corrosion ID held true Vinyl Ester is standard Push-on Joint Elliptical/Egg Shaped 40 laying length Weakness Bedding is crucial Proper storage for shape Exposure to sunlight OD can be variable Concrete collars required for buoyancy

13 Construction Challenges River flooding Working inside the Levee Existing Horizontal and Vertical Revetment Equipment fueling spill containment Soil Conditions Shoring Dewatering Existing Utilities Potholing by City Bypass Pumping for WRF tie-in Power supply challenging Unique Requirements in Specification for Scope Definition

14 River Flooding

15 GREAT MIAMI RIVER LEVEL COLUMBIA BRIDGE ARCH STREET RR BRIDGE HIGH MAIN BRIDGE BLACK STREET BRIDGE LOW LEVEL DAM RIVER LEVEL WITH GATES INPLACE EL 562 FEET SMART PAPER INTAKE TWO MILE DAM RIVER LEVEL WITH GATES REMOVED EL 555 FEET FIGURE 2

16 Soil Conditions WRF L E V E E LOW LEVEL DAM SMART TWO MILE PAPER INTAKE DAM FIGURE 3

17 Soil Conditions

18 Original Levee Construction 1922 High Main Bridge Black Street Bridge 18

19 1922 Levee Construction

20 1922 Levee Construction

21 Revetment Replacement Detail

22 Revetment Replacement Detail

23 Flexible Concrete Revetment installed 1920 s River Crossing

24 Scope Change All permits received, easements in place, Bidding Significant Industrial User Closes Plant Loss of 250 jobs 3 MGD water usage Possible Use of 42 /48 Interceptor 2 nd SIU closes 2 weeks later Change from convey/ store to conveyance Reduce pipe diameter (reduce $) Move all storage to WRF Opening up the pipe design Preliminary Cost $16M

25 Existing Interceptor

26 Summary Open process Early action with Stakeholders Make decisions consultants advise, owners decide Contingency Allowance Separate line item on Bid Form Unique Requirements in Specifications Defines Contractor Scope Bidding Fairness

27 Questions