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.
East of Brandon, the Assiniboine River 1 no longer flows on the floor of a glacial spillway; but is incised into the delta it deposited into Glacial Lake Agassiz. Even so the river has managed to create a narrow flood plain that is frequently inundated in spring. Nineteen -seventy-six was a bad year for floods by rivers in southern Manitoba. The photo shown here was taken on April 10 of that year, soon after the spring melt; in fact snow (very light-toned of course) can still be seen on the steep south wall 2 and the gentler north wall 3 of the valley. The river channel is imaged as a dull grey 4 except where specular reflection produces a light spot 5. At least five abandoned channels can be identified in this area 6, that in the southeast being Big Island 7, newer than that in the southwest DeGueldres Lake 8. They are both still partially ice covered, with snow on the surface producing a very light tone 9 compared with the grey of open water 10. Some fields are partially covered by water 11, whereas others are dry with dark-toned wet patches 12. Attempts—partially successful—have been made to protect fields from flooding; for example, a dike 13 encircles the abandoned meander loop inside DeGueldres Lake in the southwest. Another dike protects a field to the east 14, although judging by its dark tone, 15 it is very wet. North of these two areas, floodwaters have encroached behind another dike 16.
Vertical air photograph: A7612-00-123
Flight height: ; lens focal length:
Scale: 1:15,800 (approx.)
Date: April 10, 1976
Location: Township 8; Range 13WI
Map sheets: 1:250,000 62G Brandon
1:50,000 62G/11 Glenboro