||Jones, A, Stethem, C and Fogolin, K. 2010. Avalanche hazard management at the East Toba River and Montrose Creek hydroelectric projects, south Coast Range, British Columbia. Presented at International Snow Science Workshop.
|Abstract/Description or Keywords
||The East Toba River and Montrose Creek Hydroelectric Project is located in the South Coast Range 100 km north of Powell River, British Columbia. The project incorporates run-of-river intakes at East Toba River and Montrose Creek connected by 156 km of 230 kV transmission line, as well as diversion dams, penstocks, powerhouses and roads. 101 avalanche paths were identified in the project area capable of affecting facilities. These paths were mapped on a GIS and used for location planning of facilities, planning for mitigation and ultimately the avalanche atlas for the construction avalanche safety program. Due to other site constraints (engineering, hydrology, etc.), the Montrose Creek intake was located in the runout zone of a very large avalanche path which has the potential to produce Size 5 avalanches. Size 3-4 avalanches reached the intake site during each of the last 4 winters. The intake design was modified to account for impact pressures from direct avalanche impacts as well as large vertical snow loads from deposits and snow fall. The intake design included the construction of a 120 m long by 15 m high deflection berm that will keep more frequent avalanches out of the intake reservoir and reduce the impact pressure of less frequent, larger avalanches. Construction of various aspects of the project, including work at the Montrose intake site, was conducted during 2009-2010 and required an active avalanche safety program. On overview of the avalanche safety program is provided in this paper.