Manitoba has an abundant supply of surface water with many large lakes and thousands of smaller ones (chapter 2). However, much of the water is in the north or drains to the north where there is a sparse population. In the south dams and reservoirs have been constructed to conserve water in some areas, whereas in other places projects were designed to drain water from the land to make it suitable for cultivation. The province’s rivers offered enormous potential for hydroelectric power, much of which has now been exploited, starting with a small-scale project on the Little Saskatchewan River and progressing to large projects on the Winnipeg, Saskatchewan and Nelson rivers. Two thermal power stations at Brandon and Selkirk on the Assiniboine and Red rivers illustrate the need for an assurred water supply. Flooding has been a problem since the earliest days of the province, especially along the Assiniboine and Red rivers culminating in the 1997 “Flood of the Century” in the Red River Valley. Dams, diversions and ring dikes are used to divert the floodwaters to less critical areas.
All the dams illustrated in figures 16.1 to 16.10 were constructed, at least in part, to retain water for domestic, agricultural, or municipal use. But the St. Andrews Dam 1 across the northward-flowing Red River 2 was built between 1900 and 1910 primarily to allow river transport between Winnipeg (to the south) and Lake Winnipeg (to the north). The Lister Rapids on the Red River had hindered boat travel along the river since the time of the fur trade. The dam is one of only three camere-style removable structures in the world, the other two being on the Seine River in France. The design of the dam involved ingenuity, because a permanent dam structure would have caused ice jams during the spring leading to flooding upstream. The dam features “the French camere curtain design [that] uses wooden curtains to control water levels. The hinged slats of Douglas fir roll up and down as a blind does.”[i] The curtain is placed in the water during the navigation season and removed during the winter. A lock at the west end 3 allows boats to bypass the dam. Over the years commercial traffic between Winnipeg and Lake Winnipeg has declined, but the lock is still used by pleasure craft. A bridge deck was added to the dam in 1913 and now carries PTH 44 4 across the river linking west 5 and east 6 Lockport. Also the dam provides an artificial summer water level in the city of Winnipeg, the benchmark elevation for many structures along the river. There is good fishing for walleye and record-sized catfish in the rapidly flowing water below the dam 7. Note also, this area along the Red River is divided according to the French long lot system resulting in long narrow fields running back from the river 8 with houses at the narrow ends of fields in strip developments along roads running parallel to the river 9. The photograph was taken before construction of the Red River Floodway that enters the Red just downstream from the dam.
Figure 16.11: St. Andrews Dam and Lock
Vertical air photograph: A11911-305
Flight height: 9,350 feet a.s.l.; lens focal length: 152.4 mm
Scale: 1:17,000 (very approx.)
Date: May 24, 1949
Location of the west end of the dam 50º 05'N; 96º 56'W
Map sheets: 1:250,000 62I Selkirk
1:50,000 62I/2 Selkirk
[i] Lebrecht, S. Trans Canada Trail Manitoba. Ottawa: Canadian Geographic Enterprises, 2003, 266.