| The Coanda intake system was chosen
by project engineer Jorgen Jensen (Villholth Jensen & Associates,
Ltd. http://www.vja.bc.ca) for its’ ability to
finely screen intake water to the extent that collection
pits were eliminated. Mr. Jensen researched existing
Coanda intakes in the United States and made several
changes; the acceleration plate radius was increased
and the
lower end of the Coanda moved downstream. These changes allow the Brandywine
Creek Coanda to operate at river flows substantially higher than the design flow.
Utilizing tilted wedge wires and all stainless steel
construction, the Coanda intake self-cleans and screens
minus 2.0 mm particles (Typical hydroelectric screening
is 1.0 mm to 2.0mm). A municipal coanda can utilize
screens as fine as 0.25 mm.
The first-generation Coanda intake was damaged during
the massive floods of 2003. Originally designed for
100-year flood conditions, flows were estimated to
have reached 500-year levels.
The second-generation coanda was redesigned to be substantially
heavier and grizzly bars added for further protection.
The
intake is located on Brandywine Creek, which flows
into the heakamus River near the resort municipality
of Whistler, BC. The project was a result
of a contract between Rockford Energy Corp and Ledcor
Power to design/build a 7.6 MW hydroelectric power
station. As part of the agreement, 100% of the electricity
generated will be purchased by BC Hydro and will serve
Western BC.
The Coanda is positioned atop a concrete weir where
up to 4 CM/s of water is diverted into a 1.1 meter
diameter penstock. The powerhouse is located approximately
4.5 kilometers downstream.
The IPP project was well received by the local municipality
of Whistler as part of British Columbia’s Green
Power Initiative. It will seek “Ecologo”
certification under Environment Canada’s
“Environmental Choice Program”.
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