Sooke Flowline

Sooke Flowline

A section of the Sooke Flowline
Official name	Sooke Flowline/Aqueduct
Begins	Sooke Lake Reservoir
Ends	Humpback Lake, Sooke Hills Regional Park Reserve
Owned by	CRD Water District
Length	44 km (27 mi)
Diameter	1.07 m (3 ft 6 in)
Construction began	1913
Opening date	1915-1970 (East section) 1915-2009 (North Section)

The Sooke Flowline is an abandoned 44-kilometre (27 mi) concrete aqueduct that snakes through the Sooke Hills from Sooke Lake to the Humpback Reservoir near Mt. Wells Regional Park. From this reservoir, a buried, riveted steel pressure main transported water to Victoria. In between 1994 and 2007, this main was replaced since it was long past its useful life. The flowline was vital to the continued growth of the City of Victoria as it provided a reliable water supply.

Elk Lake used to be the water supply for Victoria and when the Colquitz River was dammed, it merely flooded the swamp and merged Elk and Beaver Lakes. Unfortunately the intake was at the swampy, shallow end of the reservoir. In the early 1900s, it was determined that Elk/Beaver Lake could no longer meet Victoria's water needs. The daily draw from the lake was just too great and despite measures taken to buy time, such as filter ponds, the pressure and supply was too little and sediment and amphibians were getting drawn out through the lake's intake.

During the year of 1912, the city expropriated 40 property owners on Sooke Lake and on the proposed flowline right-of-way (ROW) at great cost. The city hired the Pacific Lock Joint Pipe Company to cast the pipe segments and using their patented design, constructed the pipeline. In between 1911–1915, this major engineering project employed over 400 workers and housed their families in rural Sooke. The pipe is almost completely at a constant elevation. Although figures vary, the slope from Sooke Lake to Humpback is between 0.0947% and 0.119% when the inverted siphons are excluded.

At the factory located at Coopers Cove, at the site of today's Stickleback Bar and Grill, round concrete segments, 36,000 in all, were mass-produced. The engineering firm, Sanderson and Porter, specified 40-inch pipe, but the company already had 42-inch molds made up so they decided to use them instead. The factory was very efficient and used steam to accelerate the curing of the concrete segments. In one 8-hour shift, 150-160 segments were produced. The segments were winched up the hill 450 feet (137 m) above the construction site. Three small locomotives were used to bring segments to both ends via a temporary 2 ft (610 mm) gauge railway and the pipe was constructed from the ends to the midpoint. At the ends, tripod derricks would unload the segments and placed them on the crushed railbed while the tracks were removed. All trees on the 100 ft (30.5 m) right of way were cleared so that they could not fall and crush the pipe.