Hydrological and geotechnical studies have found no “show-stoppers” so far to excavating Grohman Narrows, BC Hydro told a public meeting Monday.
But the 80-plus people who turned out at the Prestige Resort to pose questions expressed skepticism and little overt support for the project.
The crown corporation is considering deepening the Kootenay River channel along a two kilometre stretch west of Nelson to improve flood control and power generation. It follows last year’s unusual lake and river levels, which were the highest since 1974, due largely to record rainfall.
Scenarios under consideration would see the Narrows dredged one to three meters (three to nine feet) and about 600,000 cubic meters of material removed. Project managers said it could reduce peak levels by 1.5 to 2.5 feet (0.5 to 0.8 meters) and also their frequency and duration.
Additionally, it would increase power generation by one to 1.5 per cent per year for BC Hydro’s Kootenay Canal, the four FortisBC plants, and Brilliant dam.
The Corra Linn dam would remain the key controller of water levels. Presently it regulates the river about eight months of the year, but Grohman Narrows is a constraint from mid-March until the freshet ends in July.
However, some downstream residents questioned the project’s drivers and called it an inordinate amount of work for a problem that only occurs once every few decades.
“I see no point in this other than economics for Hydro and the locals get upset every 30 years,” one man said. “This has nothing to do with us. It’s for BC Hydro and the public purse.”
BC Hydro systems manager Kelvin Ketchum insisted flood control is the main goal but “there’s no question there are energy benefits.”
He said preliminary work conducted last fall and this past spring concluded bedrock beneath the channel is deeper than first thought. “The bedrock issue could have been a show-stopper, but I think we’ve eliminated that one,” he said.
Rod Retzlaff of Glade said he’s concerned the project will negatively affect the community’s ferry: “If you dredge the Narrows, you’re going to increase the flow at Glade and the ferry may not be able to operate during the freshet.”
BC Hydro engineer Dave Straijt responded they would have more flexibility to space out water releases at freshet, preventing extremely high peaks.
Rural Kaslo regional director Andy Shadrack said he hasn’t decided whether he supports the project, but pointed to Lardeau Valley farmers inundated last summer. “This is not just a Hydro generation issue, this is a flooding issue,” he said. “We have to look at everybody impacted around this lake.”
Others said they were concerned about maintaining fishing and recreational values on the West Arm.
While supporters weren’t as vocal Monday, they do exist.
“I think it’s a worthy project. Go for it,” Beasley resident Al Craft said. “It’s not going to make mudflats, it’s just going to better regulate [the river]. With the bottleneck removed it’s going to be easier to control [and mean] better management of the water system.”
Project manager Radmila Krzman told reporters the meeting gave her a good indication of where concerns lie.
“When we started, the information we were getting was the community was overwhelmingly in favour because of flooding issues,” she said. “What I heard tonight is there are people for whom flooding is not necessarily an issue, but there might be other [issues] like potential for lower water levels.”
BC Hydro still has to figure out how much the work will cost and weigh that against the potential benefits. The first phase runs until October after which Hydro will decide on the project’s feasibility. Any physical work wouldn’t begin for another two to three years.
The Narrows were last dredged and widened in the 1930s. BC Hydro says the focus this time would be on deepening the channel.
Previous excavation efforts at Grohman Narrows
1890: An estimated 18,000 cubic yards of blasted rock, boulder and gravel removed from the riverbed.
1931: Approximately 350,000 cubic meters of rock and 200,000 cubic meters of boulders and gravel removed from six locations between Corra Linn dam and Grohman Narrows.
1939: Approximately 14,000 cubic meters of rock removed from the left bank of the river opposite Grohman Creek and 256,000 cubic meters of boulders and gravel removed from the Grohman Creek fan and from either side of the wooded island in the Narrows.
Source: BC Hydro