Canada’s BC Hydro plans to reduce levels at Hayward Lake reservoir to below 41.4m for an interim period of three to five years, until a permanent seismic reinforcement of Ruskin dam is designed and implemented.
This measure is being implemented as BC Hydro has recently determined that the 59.4m high concrete dam does not meet the most recent and more stringent dam safety earthquake standards.
‘Public safety is BC Hydro’s top priority and lowering the reservoir until a permanent solution can be implemented will improve the safety of people fishing downstream of the facility in the unlikely event of a large earthquake affecting the dam,’ said BC Hydro’s General Manager of Generation, Coastal Region Chris O’Riley.
Normal reservoir operations under BC Hydro’s existing water license range between a high of 42.6m and a low of 41.08 or 39.5m, seasonally dependent. Between 15 February and 15 May, and 15 October and 30 November annually, the minimum reservoir elevation is 39.5m; the remainder of the year it is 41.08m. Pending an amendment to the water license, which will allow reduction of the reservoir elevation to 40.7m, the reservoir level will be held at the low end of the level approved in the water license.
Water supplies originating from Hayward Lake Reservoir are not expected to be impacted at these levels because their intake levels are below the proposed minimums, and environmental impacts are anticipated to be minimal as a result of limited exposure from the reduced reservoir level.
Ruskin dam impounds Hayward Lake reservoir on the Stave river, downstream of the 105MW Stave Falls power plant.