A spectacular legacy of the last volcanic eruption in southwestern B.C. would be seriously impacted if a run-of-the-river power project proceeds on the upper Lillooet River.

Keyhole Falls, located about 60 kilometres northwest of Pemberton, is where the Lillooet River bursts forth from the volcanic rubble of Mount Meager's last eruption almost 2,400 years ago.

But the tap on the 25-metre-high falls would be turned down if Creek Power Inc. proceeds with plans for three independent power projects producing a total of 113 megawatts on the upper Lillooet River system.

The company wants to divert water above the falls and send it through a tunnel to a powerhouse downstream, thereby reducing the flow over the falls.

Joe Foy of the Western Canada Wilderness Committee called on his 28,000 members to demand the province reject the power project and urge an end generally to the costly continuing giveaway of public rivers to private business interests.

"This is crazy," he said. "It makes no sense to steal Keyhole Falls."

To date, 42 run-of-river power projects are in operation in B.C., about 70 per cent producing 10 megawatts or less each. Another 617 projects are in the application stage. A total of 289 water licence applications have been refused or abandoned.

Creek Power of North Vancouver is owned two-thirds by Innergex Renewable Energy Inc. and one-third by Ledcor Power Group Ltd. and is in the midst of a provincial environmental assessment.

Innergex's western region vice-president, Richard Blanchet, said consultants are looking into the impact of the diversion on fish downstream as well as on plants and animals.

They are also examining the river flows and levels of public visitation to the falls at various times of the year in hopes of coming up with a plan to alleviate any concerns.

"We may be able to provide esthetical flows," perhaps on weekends, he said, noting the river levels fluctuate but average about 45 cubic metres per second annually.

People visit Keyhole Falls in small numbers year round, including by snowmobile. "They say it's quite gorgeous during the winter months," Blanchet said.

The company would also be required to build a 230-kilovolt transmission line across 72 kilometres to connect with the grid at Rutherford Creek, south of Pemberton.

Frank Baumann of Squamish is a geotechnical engineer and outdoors enthusiast who has worked on about 30 independent power projects in B.C., including for Ledcor.

He has looked at the Creek Power proposal and believes it is generally a good one, the tunnel serving to lower the company's footprint on the site. Whether it's worth the impact on Keyhole Falls is something that the public and government must decide.

"It would definitely reduce the amount of water that goes over the falls," he said. "For certain parts of the year there would be a noticeable reduction."

Blanchard noted there is not good trail access to the falls, something the company could improve with its project, although he noted some people like it the way it is.

Paul Adam has visited Keyhole Falls several times while exploring the region's hotsprings and volcanic history. The best view involves more than two hours of bushwhacking to the base of the falls; the walk to the top of the falls takes only a few minutes from a logging road bridge, but can be dangerous due to steep drops and no guard railings. "You have to hang onto a tree and look down."

The Creek Power project would include the generation of 16 megawatts of electricity at North Creek, 23 megawatts at Boulder (Pebble) Creek, and 74 megawatts on the Upper Lillooet River, the two smaller facilities dependent on the larger being approved.

Creek Power was awarded three electricity purchase agreements for the respective hydroelectric facilities last March for a 40-year term in response to BC Hydro's 2008 Clean Power Call.