The Glenmore Reservoir is a large manmade reservoir on the Elbow River in the southwest quadrant of Calgary, Alberta. The Glenmore Dam is the concrete structure that holds back the reservoir. The reservoir is the primary source of drinking water to the city. Built in 1932, with a cost of $3.8 million, the dam controls the downstream flow of the Elbow river, thus allowing the city to develop property near the river's banks with less risk of flooding2.
The City of Calgary offers sailing lessons and boat rentals on the reservoir.
The reservoir has a water mirror of 3.84 km² (1.48 sq mi) and a drainage basin of 1,210 km² (467 sq mi).1 It has a mean depth of 6.1 m (20 ft) and reaches a maximum depth of 6.1 m (20 ft).
Calgary pioneer Sam Livingston originally settled at the location of the reservoir, and he gave the name Glenmore (Gaelic for "big valley") to this area.
The dam was completed on 31 January 1933.1 When the area flooded (by the summer of 1933), part of the Livingstone house was preserved and now stands in Heritage Park, which borders on the reservoir.
2005 flood
Although the dam usually provides effective flood protection, a major flood in June 2005 caused the reservoir to exceed its capacity. The excess spilled over the dam and into the river3. The flow downstream increased from its normal average of 20-30 cubic metres per second up to 350 cubic metres per second. As a result, some roads were closed and 2,000 Calgarians who lived downstream were evacuated. The Glenmore water treatment plant had difficulty treating the heavily silted water. Ironically, this caused the municipal government to issue water restrictions. The Albertan government estimated the floods in the area to be the heaviest flooding in at least two centuries.
The Glenmore Water Treatment Plant, constructed in three phases in 1933, 1957 and 1965, is a conventional treatment plant that gets its water from the Elbow river. The Glenmore plant supplies drinking water to south Calgary.
The reservoir is maintained at a level, depending on the flow rate of the Elbow river, that minimizes the risk of flooding around the reservoir and downstream of the dam to the greatest degree possible.
The dam, one of the heaviest in North America, is 320 metres long with a base width of 21 metres.
Dams such as Glenmore use the downward force (gravity) of the weight of the construction materials,(concrete), to resist the horizontal force of the water they hold. These massive dams resist the thrust of water entirely by their own weight.
In deep water, there is more water "piled up,"causing the pressure to be greater at the bottom than at the surface. A dam's design must enable it to withstand greater pressure at the bottom than at the top.
Dams such as the Glenmore store water for drinking and for recreation, while others make electricity. They also help control flooding, although the Glenmore was not specifically built for this purpose.
During periods when the rate flow of the Elbow River reaches dangerous levels, water may be released from the dam to prevent overflow4.
