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Whistler Creek Management and Debris Barriers
Winner of the Consulting Engineers of BC's
Award of Merit
Setting new design standards for debris containment, the Whistler
Creek debris barriers can withhold a volume equivalent to 12
Olympic-size swimming pools and withstand the impact of a two-meter
boulder travelling at five metres per second.
Enabling Whistler Creek Development
Intrawest's Whistler Creekside development will be a smaller,
more laid-back alternative to Whistler Village. Located on the
alluvial fan of Whistler Creek, a flood and debris flow hazard
zone, the development would have been impossible without the
Whistler Creek Management works designed by Kerr Wood Leidal
Associates (KWL).
Design Objectives and Features
The objectives of the project were to provide a high standard
of flood and debris flow protection, while improving fish and
wildlife habitat and creating a visually-attractive creek corridor.
The work centres around the creek above Highway 99 and consists
of: two debris barriers upstream of Whistler Creekside; over
600 metres of extensively upgraded creek channel; two bridges;
a secondary floodway for future emergency flood protection;
and an extensive landscaping program.
Debris Barrier System
The most difficult challenge was the design and construction
of the primary debris barrier. Due to its huge size and the
forces it had to withstand, no standard design guidelines were
applicable, making the structure a true custom-engineered solution.
The primary debris barrier is one of the largest in the province
at about 12.5 metres high, with a debris storage volume of 24,000
cubic metres. It consists of rugged structural steel grillage
supported by mass concrete abutments. The steel grillage is
sized to withstand the impact of a boulder two metres in diameter
travelling at a velocity of up to five metres per second. During
a major debris flow, most debris will be contained within a
bedrock ravine behind the primary debris barrier, protecting
the Whistler Creekside development.
Apart from its size, it is unique in that minimal blasting and
excavation was required to construct it. The minor amount of
excavation required not only improved the aesthetics of the
debris barriers, but also shortened the construction time and
saved the client considerable construction costs.
A secondary debris barrier, of similar construction but much
smaller scale, is located downstream of the primary barrier.
It is designed to arrest smaller sediment surges that pass through
the primary barrier thus enhanced fish habitat by reducing siltation
downstream of it. Both structures are designed to withstand
debris surges up to 400 cubic metres travelling at six metres
per second.
Effective Protection
The Whistler Creek works provide excellent flood and debris
flow protection to Whistler Creekside and other developments
downstream with the added benefits of an attractively restored
creek, improved fish habitat through silt interception and creek
channel enhancements, and improved wildlife habitat through
planting of fruit-bearing vegetation. In fact, the debris barriers
reduced the downstream risk to such an extent that no large,
and potentially unsightly, engineering works were required at
Whistler Creek.
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