by Mike Willmets, City of Ottawa Derek Potvin, P.Eng., Robinson Consultants

1. City of Ottawa’s Lemieux Island Transmission Main Replacement ProgramLow and High Pressure Transmission Mains by Mike Willmets, City of Ottawa Derek Potvin, P.Eng., Robinson Consultants

2. Presentation Outline • Water Works History • Existing Conditions • Construction

3. Project Location

4. Project Overview 5 km of 1200, 1675, 1980 mm diameter Transmission Main • Serves 400,000 people within City of Ottawa. • Replaces three discharge mains from Purification Plant. • One of the Transmission Mains operates as a low pressure (gravity) suction supply for a Fleet Street Pumping Station and the other operates at distribution system pressure.

5. Water Wagon – Pre 1874

6. Why Supply Drinking Water? • Water delivered by horse & wagon in wooden barrels • Era of Great Fires: Quebec City in 1845, Montreal in 1852, Carleton County in 1870, Chicago in 1871 • Fire Insurance Underwriters • Toronto - 1841, Kingston - 1850, Hamilton - 1860

7. Thomas Coltrin Keefer1821 - 1915 • Father of the Ottawa Water Works • One of Canada’s greatest engineers • Built similar water systems in Montreal, Hamilton & Toronto

8. Harnessing the Chaudiere Falls

9. Fleet Street Pumping Station • Commissioned 1874 • Utilizing hydraulic energy of Chaudiere Falls • 765m open aqueduct built • Capital Cost of $266,000

10. Ottawa Fire Brigade 1874

11. Great Fire of Ottawa-Hull 1900

12. Ottawa’s Great Fire - 1900

13. Typhoid Epidemics • 1 epidemic in 1911, 2 epidemics in 1912 • 1900 to 1915 - 512 related deaths • 1916 to 1925 - 18 related deaths • Nepean Bay pollution

14. ABC Lines Lemieux WPP Fleet P.S. • Three of the most important mains • Critical to operation of system • Unique Pipes in a Unique Setting

15. Lock Bar Pipe • Two semi-circular sections joined by a ‘lock bar’ • Lock bar is long strip of metal with an ‘H’ shaped cross section • Riveted joints to join pipe to pipe

16. Delivery of “A” Line Piping 1915

17. “C” Line Construction 1937 - 50

18. Existing Pipe Condition • Corrosion pitting leads to leakage. • Corrosion of rivets & lock bar can lead to pipe failure. • “A” & “B” Line’s cement lining (circa 1950) was delaminating which accelerated internal corrosion. • “C” Line was in good condition but required relocation for planned development.

19. Site Constraints • Federal Land • LeBreton Flats Development • Past Land Uses • Breezehill/Scott Feedermains • Subsurface Conditions

20. Existing Site Conditions • Adjacent to former Municipal Waste Site » Contaminated Soils and Groundwater » Highly Corrosive Environment. • Area formerly part of Ottawa River » Significant area of unconsolidated fill material. • Adjacent to Ottawa River » Dewatering issue during construction. • Area formerly an industrial development » Subsurface remnants and contamination. • Crossing major transportation corridors » Traffic Implications. • Construction within existing aqueduct channel » Protection of watermain. • Construction within existing AWWA Canadian Waterworks Landmark and Heritage Structure » Fleet Street Pumping Station. Lemieux Island WPP Fleet Street Pumping Station

21. Historical Land Uses

22. Lemieux Island WPP Bayview Yards Low Pressure WM Nepean Bay High Pressure Transmission Main Wellington Street Albert Street Subsurface Conditions

23. Geotechnical Conditions • Unconsolidated fill from Nepean Bay and Ottawa River Parkway over bedrock • Long term settlement concerns and significant dewatering

24. Dynamic Compaction • Large Un-consolidated Fill Zone on reclaimed land » former bay of the Ottawa River. • Dynamic Compaction used to prepare watermain alignment prior to construction. • Large steel weight dropped from crane to achieve consolidation. • Compaction can be achieved to over 10m depth. • Compaction carried out using grid pattern to cover area. • Compaction testing carried out after completion.

25. Corrosion Potential Investigation

26. Preferred Alignment

27. Design Requirements • 100 Year Design Life Required. • Must maintain water supply to customers. • LPTM to serve dual purpose » Operate primarily at low pressure with conversion to high pressure based on demand. • HPTM to supply water to distribution system from pumping station at WPP. • Must maintain access to existing purification plant. • Must protect existing heritage structures » Fleet Street Pumping Station and Open Aqueduct.

28. Watermain Materials • Concrete encased, polyurethane coated, steel pipe and concrete pressure pipe utilized to protect against corrosion. • Gasketless, double lap welded, bell and spigot joints specified to protect against groundwater ingress in landfill zones. • Transition between material types at valve chambers. • Cathodic protection installed throughout.

29. Ruins from Previous Development • Previous railway structures, bridge abutments, building foundations and superstructure debris uncovered in the watermain excavations. • Previous factory foundation and tunnel uncovered within the excavations.

30. Concrete Encasement • 150 mm concrete encasement • Pipe strapped to concrete slabs to counterbalance buoyancy

31. Open Aqueduct Installation • Coated concrete pressure pipe installed in existing open aqueduct channel. • Channel is a “neighbourhood feature” and a designated heritage structure. • High density polyethylene shield added to protect watermain from objects falling or being thrown into water. • Gasketless expansion joints used between fixed supports to allow for temperature movements.

32. Fleet Street Pumping Station • Existing AWWA Canadian Water Works Landmark and heritage structure. • Turbine pumps driven by water from Ottawa River » fed by aqueduct system. • Connection of new transmission main with valve chamber to switch to high pressure operation » by-passes pumping station. • Included replacement of existing suction header piping in station. • Installation of sluice gates to isolate pump turbines from aqueduct flows during maintenance. • Included measures to protect existing structure from damage during construction.

33. Bridge Pipe Rehabilitation • Couplings repaired and internal joints seals installed.

34. Tunnel Construction • Transmission Main constructed in casings across major roads, parkways, railways and rapid transit bus route. • Steel pipe electrically isolated from casing pipe via casing spacers. • Annular space grouted.

35. Ottawa River Parkway Crossing • Crossing of existing federally owned four-lane, divided parkway required. • Open trenching construction due to presence of methane from landfill » explosion hazard during jacking and boring operation. • Existing fill material not suitable for jacking and boring » large boulders. • Installation of concrete casing pipe completed over one weekend road closure. • Welded steel watermain inserted by jacking methods after completion of casing.

36. Not all goes as planned! • Steel pipe partially collapsed during grouting. • Protrusion cut out, grout removed and new repair sleeve welded in place.

37. Valve Chambers • Steel pipe continued through the valve chambers. • Features: air valves, drain valves, line valves, branches and access manholes

38. Thank you ! Merci !