Cheakamus included in BC Hydro licence review
Whistler to participate
By Chris Woodall
The Daisy Lake hydro dam and the Cheakamus watershed it is part of will be one of 10 initial BC Hydro developments under licence review, the province announced last week.
The province will eventually review all 34 BC Hydro water licences, but the Cheakamus River development heads the list of the government's first priorities.
Whistler has already undertaken its own study of the Cheakamus watershed and will take part in the review process.
"The municipality will want to look at a lot of the issues associated with a healthy river," says municipal engineer Brian Barnett, who'll be on the watershed management review committee.
The committee will involve Whistler, Squamish and other affected communities or groups. Its initial stages will determine what it will do and how it will do it.
There has been concern for many years that BC Hydro has abused its licence when it comes to regulating water flow out of Daisy Lake dam. Most of the water behind the dam goes through the tunnel under Cloudburst Mountain to the generating station on the Squamish River. What BC Hydro doesn’t need for power generation is allowed to continue down the Cheakamus River.
Some of BC Hydro's water licences are decades old and were developed at a time when fishery values or flood control were not priorities, says a Ministry of Environment, Lands and Parks news release.
"BC Hydro has exceeded its Daisy Lake dam licence for 36 of 38 years it's had it," Barnett says of the utility diverting water to the generating station.
"It's important that they're not following their own guidelines," Barnett says. "More importantly, we have to understand that impact on fish stocks, which need certain water flows for spawning and for the growth of fish food."
One of the problems with BC Hydro's licence is that it does not determine a minimum flow rate into the Cheakamus River.
The current licence of 700,000 acre feet per year could be poured through in two months or 12. High flows of water strip algae off rocks and force fish to relocate further downstream.
Whistler's study will add ammunition to the review process.
The $150,000 study by Vancouver firm Limnotek will be completed by the end of this year with a report due by May, 1997, Barnett says.
"It's one of the leading studies of watershed management in B.C.," Barnett adds.
Ongoing tests in the study sample such things as water temperature, nitrogen content, sediment levels and the effect of sediment on the amount of light filtering through the river water.
"It's a really complicated process," Barnett says.
Tributaries of the Cheakamus, for example, have different water temperatures. Rubble Creek has a higher temperature than other creeks because of thermal heating.
If more Rubble Creek water is allowed to flow into the Cheakamus relative to the over-all volume, then the average temperature rises, Barnett says. Temperature levels affect the ability of algae — fish food — to grow.
Instruments at various locations are sampling changes in temperature every 30 minutes. That information is combined with data from other sensors to provide a picture of the health of the river being tested, Barnett says. One type of sensor calculates the amount of light reaching the river bed.
"There's only a certain band of light frequency that stimulates algae growth," Barnett explains. Higher silt content darkens the river bed.
The outflow from Whistler's sewage treatment plant may have downstream effects on watershed health, too.
"It's a very fun, interesting study," Barnett says.
The province promises that the general public will be involved in developing facility-specific plans and to review water use plan guidelines.