BC Hydro says it could cost as much as C$70 million (US$66 million) to mitigate piping and seismic risks at 67.5-MW Strathcona Dam, an earthfill dam constructed in the 1950s.
BC Hydro previously acknowledged its dam did not meet modern-day standards, noting internal erosion could occur within the dam core. Over time, the utility said, erosion could result in sinkholes or subsidence of the crest and lead to dam overtopping.
In its 2007-2010 service plan, the province-owned utility said it is studying how best to mitigate piping and seismic risks at the dam. In addition to possible internal erosion and degradation in the dam, BC Hydro said the concrete intake structure, the adjoining conduit through the base of the dam, the dam itself, and the spillway might be at significant risk in an earthquake.
BC Hydro estimates the total cost for a Strathcona Dam seismic and seepage project could range from C$50 million to C$70 million (US$47 million to US$66 million). It also set a targeted completion date of 2010 for the work.
BC Hydro upgraded the dam’s crest in 2005 to provide the Campbell River hydroelectric system with increased capacity to accommodate extreme floods. (HNN 11/23/05) The Strathcona powerhouse is one of three generating stations in the utility’s Campbell River System, on British Columbia’s Vancouver Island. (HNN 7/26/06)