June 24, 2011

PHOTOS: CITY OF THUNDER BAY

Modern aerial view of the system.

FEATURE | Sewer and Watermain/Water & Wastewater

Genivar engineer compiles history of Thunder Bay, Ontario water supply tunnel

PETER KENTER

correspondent

If there’s one thing that structural engineer Larry Betuzzi believes in, it’s keeping accurate project records. The structural engineer with Genivar’s Thunder Bay office has logged the details of the city’s Loch Lomond Water Supply System, right down to the salaries paid to local workers to complete the project.

Top mechanics on the job earned 40 cents per hour, while project superintendents raked in $150 a month — pretty good for a project completed in 1909.

Betuzzi became interested in the story of the city’s first modern water system when his company worked on a contract to brace a century-old sluice gate at the Loch Lomond Gate House.

“Before that time, I wasn’t even aware that there was a tunnel carved through the rock from Loch Lomond,” says Betuzzi. “While I was inspecting the gate house, the City of Thunder Bay Public Works manager, Mike McLeod and I got into a discussion about the history of the water system and the rest is history.”

PHOTOS: CITY OF THUNDER BAY

Engineering drawings of the Loch Lomond water system, circa 1900.

Loch Lomond is a spring-fed lake about 10 kilometres south of Thunder Bay, with an elevation about 100 metres above Lake Superior, making it an ideal gravity-fed water source. When the area was hit by a typhoid epidemic in 1905, the city of Fort William moved on plans to switch water sources from the polluted Kaministiquia River to Loch Lomond.

With persistence and repeated trips to the Thunder Bay library and city archives, Betuzzi compiled a history of the system, from design through to commissioning. The best resource, he says, was a book by Fort William city engineer, H. Sidney Hancock Jr.

“The writing in those days was quite a bit different in terms of the details and structure,” says Betuzzi.

PHOTOS: CITY OF THUNDER BAY

A tunnel carved through rock connecting the lake and the city water system.

“The book told the story of the system, but not in chronological order, so it took a bit of work to organize the details.”

Work began in 1906, but since it would take several years to complete, the city constructed a temporary water works using Crescent Lake, five kilometres away, as the source. The Contractor, Wm. Newman & Co., of Winnipeg was awarded the project at a price of $118,000, including construction of a road, reservoir and mains. The project was plagued by problems.

“The pressure main was made of tongue-and-groove wood staves, tightened at the joints with metal hoops,” says Betuzzi. “Unfortunately it leaked like a sieve, losing about 375,000 gallons per day. As one city manager was quoted: ‘...under these circumstances, I do not think the pipeline can be said to be very efficient.’ ”

The Loch Lomond contract included construction of the tunnel and tunnel shaft, gatehouse and intake pipe. The work also included 4.5 miles of road, constructed through bedrock, swamps, muskeg and steep hills. Among the positions filled: drillers, muckers, landers, hoistmen, blacksmiths, compressor men and mechanics.

A tunnel was cut through solid granite, using dynamite in a typical “drill-and-blast” operation at 5.5-foot intervals. The minimum finished cross section of the tunnel was four feet wide by five feet, three inches high at a grade of 0.10 per cent. Work on the tunnel began in June 1907, constructed from a 60-foot shaft near the gatehouse.

“The intention was to line the entire tunnel with concrete, but, during construction, it was determined that only those portions indicating ‘signs of weakness’ needed to be lined,” says Betuzzi.

The 750-foot intake pipe was installed in January 1908, lowered to a depth 42 feet below lake level at the intake point. The contractor constructed a cofferdam from the gatehouse to a point about 275 feet into the lake.

“The remaining 473 feet of intake pipe was lowered in one piece from the ice,” says Betuzzi. “Water began flowing through the tunnel on June 21, 1909. Considering the fact the work was carried out in the early 1900s, this was truly an amazing feat of engineering and construction.”

Total cost of the project: about $500,000, or close to $10 million adjusted for inflation.

The system supplied water to parts of the city for almost a century. The city decommissioned the Loch Lomond water system in 2007, when it moved to a single-source system pumping water from Lake Superior through the Bare Point Water Treatment Plant.

The original rock tunnel?

“It’s still there,” says Betuzzi. “The 100-metre difference in elevation between the level of the lake and the elevation of the lowlands below is significant enough that there’s always a possibility that the Fort William First Nations may want to resurrect the system as a hydro-generating facility.”

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