10 KM N of NORTH END OF KOOTENAY LAKE
Operator: BC Hydro
Type: Storage facility earth fill dam
The Duncan Dam was the first of the three Columbia River Treaty dams to be built in the Canadian section of the Columbia River Basin. Construction began on the dam in 1965 and was completed and operational in 1967, ahead of schedule.
Duncan is an earthfill dam with no power generation facilities. Its purpose is to control the flow of water from the Duncan River into Kootenay Lake in conjunction with the Libby Dam to assure operational water levels for the Kootenay Canal and the Corra Linn projects downstream.
Duncan Lake was originally 25 km (15.5 mile) long, the reservoir is now 45 km (28 miles) in length. Water fluctuates up to 30 metres (98 feet) in elevation annually. Prior to the building of the dam, Duncan Lake and River were main navigation routes used by the mining and logging industries to extract valuable natural resources from the valley. Two competing railroads that traveled north from the head of Kootenay Lake to the town of Howser, where there was a thriving sawmill, post office, store, assay office and small farms. Some buildings were relocated to higher ground prior to the flooding, but most were left to be cleared away or burnt before flooding. The reservoir was cleared of large trees. As the water levels go down in the fall and winter, the ghostly stumps are revealed. Traces of prior settlement, with the railway bed, old roads and some foundations, are also visible at low water. When it is full for a few summer months each year the reservoir resembles the size of the original Duncan Lake only now it is surrounded by stumps rather than the abundant wetlands that once created ideal waterfowl habitat.
Duncan Dam, Declared operational on July 31, will be officially dedicated by Premier WAC Bennett at ceremony to be held at the dam site Thursday, August 17. Aerial photo shows 130-foot high structure with British Columbia's newest lake in background. Discharge tunnels are on left and spillway is on extreme right. The public is being invited to a free Bar-B-Q following the 2:00 p.m. ceremony that will feature unveiling of plaque attached to a huge rock in centre of dam. Duncan Dam is 26 miles north of Kaslo.
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