The City of Grande Prairie retained SNC-Lavalin Inc. to carry out an independent Dam Safety Review (DSR) for the Bear River Control Structure. Some key findings of the DSR were:
- The zone of influence (the area that is impacted by the dam operation) of the Bear River control structure is as follows:
- Under low flow conditions (<5-year flood) the zone of influence extends 800 metres upstream of the Bear River control structure (just downstream of the 108 Street bridge). During these flow conditions the operation of the gates has no influence on the surface water upstream of the 108 Street bridge.
- During higher flow conditions the zone of influence can reach up to 3 kilometres upstream of the Bear River control structure, which is approximately in line with Royal Oaks Drive. Due to the shape of the river valley and slope of the river channel, the operation of the control structure has no influence on the surface water beyond this point.
- The Bear River Control Structure is in satisfactory condition and there are no critical dam safety deficiencies that will require immediate action.
- The review of the reservoir indicated that there is adequate available capacity during the design storm event; therefore, there is no need for an additional overflow structure.
- The structural analyses concluded that the spillway concrete structure meets all the stability criteria set forth in the Canadian Dam Association Guidelines.
- A full list of recommendations is listed within the report.
Also Known As
Bear River Control Structure, 2020 Inundation Study and Dam Safety Review