Spruce Falls was the local name for a small waterfall where the Swan River empties into Duck Lake in northeastern Saskatchewan, near the Manitoba boundary. It is located at 55°37′ N and 102°7′ W.
The Swan River, about 6 kilometres (3.7 mi) in length, is the outlet channel from Birch Lake into Sisipuk (Duck) Lake. The water eventually flows into the Churchill River. It has a drainage area of 1,800 square kilometres (700 sq mi) consisting of a number of lakes, chief among which are Mari Lake, 49 square kilometres (19 sq mi), Barrier Lake, 140 square kilometres (55 sq mi), and Birch Burntwood Lake, 41 square kilometres (16 sq mi).
In 1928, Spruce Falls became the site of a temporary power plant supplying the Island Falls, Saskatchewan hydroelectric power development on the Churchill River.
A large amount of power is required for construction purposes on a job the size of the Island Falls development. As steam and gasoline units could be used only to a minor extent, owing to the high cost of transporting fuel, the only alternative was to find a site where hydroelectric energy could be generated. Engineers for the Churchill River Power Company determined that Spruce Falls, about 21.7 kilometres (13 1⁄2 mi) northeast of Island Falls, was suitable.
By utilizing the natural fall of 7.6 metres (25 ft) at Spruce Falls in addition to a 4.6-metre-high (15 ft) timber dam which impounded a small forebay, a head of 12 metres (40 ft) was developed. Water from the head pond was conveyed to generator turbines by two wood stave pipes 2.1 metres (7 ft) wide and 27 metres (90 ft) long.
The Spruce Falls temporary powerhouse was a frame building on the shore of Sisipuk Lake. It contained two small generating units and complementary equipment. These two 930-kilowatt (1,250 hp) vertical-type turbines, with propeller-type runners, were directly connected to 1,000 kV⋅A generators delivering power at 600 volts, 3 phase, 60 cycles to a bank of transformers.
The transformer bank was placed apart from the power-house and protected by a lightning arrester and fuses. Rated at 2,000 kV⋅A, these transformers stepped the voltage up to 26,400 volts for transmission to Island Falls. There, a sub-station stepped the current down to 600 volts for two motor-generator sets which supplied current for the electric locomotives used in hauling earth, concrete and other construction materials.