The 90th anniversary of Shoal Lake aqueduct–ruote went over swamp, muskeg, sand and rock

By admin

Actual construction on the aqueduct began after the opening of tenders on September 19, 1914. Three major Winnipeg-based companies — Tremblay McDiarmid Company, Thos. Kelly & Sons Ltd., and the Winnipeg Aqueduct Construction Company — were awarded the contracts for the aqueduct. The first phase involved the diversion of the Falcon River, which had previously flowed into Shoal Lake at Indian Bay. The diversion was a key to the project as it allowed the development of the Indian Bay source without the need for treatment based on aesthetics (colour), ac cording to Ron Sorokowski and Duane Griffin, from the city’s water and waste department, and Chris Macey and Ken Skaftfeld, of UMA Enìgineering Ltd., the authors of the 2008 article Winnipeg’s Aqueduct.

On July 5, 1915, the Free Press re ported that prior to the diversion, the Falcon River discharged dirty-looking water into a corner of the bay, as a result of swamp water draining into the river.

Before construction on a gate house and pumping station at Indian Bay commenced large boulders at the intake site were removed by blasting and a dike was built near the entrance of the bay to divert the Falcon River.

Fuertes and Chace were on-hand when the first earth for the Falcon diversion into Snowshoe Bay was lifted by a steam shovel on June 17, 1914.

The Winnipeg Free Press on March 13,1918, reported building the 7,000 foot long (2,133.6 metre) dike required “about 230,000” yards of material, all of which was obtained from a borrow pit and quarry located at the north end of the dyke (sic).

“A large number of drainage and offtake ditches were necessary in order to drain the country properly before actual construction of the aqueduct was commenced” on May 15, 1915.

Although the route for the aqueduct was over swamp, muskeg, sand and rock, overall construction was alleviated by the fact that it was downhill for most of its length with the exception of 14 kilometres from Indian Bay. A deep cut several metres down in the rough land was made during this initial phase of the aqueduct construction.

The aqueduct was built under the Whitemouth and Falcon rivers using inverted siphons. In total, four rivers were burrowed under at six locations by using inverted siphons, a process used in Roman aqueduct construction.

The trench running the aqueduct’s length was rough-cut using steam shovels, dredges and dragline scrapers with workers trimming away the remaining 150 millimetres by hand. By the end of the project, 1.65 million cubicmetres of earth had been excavated.

Less than a year into the project, the First World War intervened. The March 13, 1918, Free Press, when reporting on the history of the aqueduct, said the war had the “effect of making it much more difficult to secure money and also causing a scarcity of labor.”

Despite the pressures of the war effort depleting the available labour pool, over 2,500 workers would be involved at the peak of the project’s construction phase.

The Free Press said over the course of the first year, 21.4 kilometres (13.3 miles) of the aqueduct were built, or 14.6 percent. During the 1916 season, 37 kilometres (23 miles) were built, so that the project was by then 41.6 per cent complete.

The method used to build the aqueduct was cut-and-cover. A one-metre trench was dug and a horseshoe-shaped conduit, averaging about 2.7 metres in height, was poured between steel forms. When the concrete cured, the forms were stripped and the pipe was covered by earth, which was necessary to prevent the water from freezing during Manitoba’s cold winters.

Every 1,524 metres, manholes were installed to allow for maintenance inspections. Surprisingly, early inspections of the aqueduct’s interior involved lowering the water level and men then boating through the sections.

“The invert slabs were poured in alternating 4.5-metre-hng sections and screeded to a smooth surface,” said the authors of Winnipeg’s Aqueduct. “Once these sections were cured, closure sections were poured. Following immediately after the completion of the invert slabs, the arch was built in 13.7-metre- long sections, also in an alternating pat tern, using an inner and outer slip form. The forms were advanced along sets of rails on the middle and outside edge of the completed invert. Several reinforced crossings were provided within the up per reaches in anticipation of future road crossings

“The specifications also required that between the walls of the trench and the aqueduct select earth backfill would be tamped carefully in 150 millimetre lifts to a depth of 1.2 metres. As the designers explained, this precaution was taken in conjunction with a. moderately light design of arch.”

However, the arch was “quite safe against the pressures of earth backfill even without packed earth at the haunches.”

A steam shovel was then used to place the remainder of the backfill over “the aqueduct to a depth of 1.2 metres in the case of solid material or 1.5 metres in the case of peaty material.”

The GWWD supplied all the cement required for the aqueduct, but contractors were charged for any wasted cement.

“All aggregate (mixed with the cement to make concrete) is supplied by the district (GWWD) and delivered to the camp sites of the contractors,” reported the Free Press. “This is obtained from gravel pits along the route of the (Greater Winnipeg) Water District rail way. Machinery is maintained at the pits to crush and mix the pit run gravel, so that the aggregate is graded in such a manner to make the densest and most watertight concrete.”

By controlling the cement and aggregate, the GWWD was ensuring the concrete used in the aqueduct was of the highest quality.

As was the case in aqueducts serving ancient Rome, water from the Shoal Lake aqueduct was channeled to a massive reservoir. At Deacon, 13 kilometres east of Winnipeg, water from the cistern was distributed via pipelines to the city and the several municipalities making up the GWWD. Over the years, the main Winnipeg reservoir has been expanded to the point that it now can hold 8.8-billion litres of water, the equivalent of a 20-day supply, according to the city of Winnipeg.

The February 1,1919, FreePressre ported figures on the performance of the aqueduct: “Eighty-five million gallons (386.4 million litres) would fill Portage Avenue between the building lines from Main Street to Sherbrook Avenue to a depth of 20 feet (six metres); the con tents of the (Deacon) reservoir … combined with the contents of the reservoir now owned by the city of Winnipeg (McPhillips), would fill this same area to a depth of 63 feet (19.2 metres), or to the height of the fourth story (sic) windows.”

Chief engineer Chace explained at a meeting of the Winnipeg Rotary Club on October 2, 1918, how the water was to be piped under the Red River. “As you know, we broke through the last portion of rock bore under the Red last Saturday night. The bore, which was made through the uneven starts of lime stone rock, will be lined with cast-iron pipe 60 inches (1.524 metres) in diameter, the joints of which will be caulked from the inside. On the St. Boniface (then a separate municipality) side this will be connected with the 66 inch (1.678.4 metres) reinforced concrete pipe forming that portion of the aqueduct; and on the Winnipeg side it will be joined up with the 48 inch (1.219.2 metres) reinforced concrete pipe running along Pacific Avenue to McPhillips Street (then the site of the only reservoir within the city’s boundaries).

“After the pipe is laid along the (24- metre-deep) tunnel, we propose filling in the overbreak, which has been fairly regular, by pouring in concrete, in its thin state, from the surface of the ground down a shaft, guiding it by pipes which can be shortened as the overbreak is gradually filled.”

The scope of the project was such that a motion picture was advertised to run at the Dominion Theatre in February, “showing the construction, engineering, works, aqueduct and district from Indian Lake (sic) right through to Winnipeg.”

The advertisement said every resident of the city should view the film to obtain “a proper understanding of the importance and magnitude of Winnipeg’s great water scheme. It ranks among the major undertakings of the world.”

By the end of March 1919, the aqueduct was essentially completed.Wesley College and Students Quarters Winnipeg MB

Wesley College in Winnipeg Manitoba