Providence Lake Dam a high risk to Greenwood residents

Mona Mattei
By Mona Mattei
October 15th, 2010

With files from Lori Culbert, PostMedia News Providence Lake Dam in the Phoenix mine area (also known as Marshall Lake) has been named one of nine “high risk” dams in danger of collapse. In an investigative story published in the Vancouver Sun, Ministry of Environment officials stated that they have reviewed the nine dams and there is little risk to those living downstream.   The City of Greenwood, located in a valley west of the lake, will be the most at risk should this dam collapse. According to Christopher Stevenson, a councillor for the city, the public works staff and the city’s administrator are at the dam site today to evaluate the potential dangers. Ministry of Environment staff  have been at the site over the last two days reviewing its condition as well.   “We still need more information. We’re not sure of what this means,” said Stevenson. “At this point all we can say is that if there is a problem that we’ll do what we can as a community to make sure that those risks are minimized and mitigated.”   B.C. Ministry of Environment audits of the 2,000 dams in B.C. found that of the nine “high risk” dams, five of them are additionally classified as “high consequence,” meaning they could cause significant damage if they failed.
The information was released last week in response to a freedom of information (FOI) request filed by the Vancouver Sun, following the collapse in June of the Testalinden Lake dam, which caused extensive damage to 14 private properties in Oliver, B.C.
In an interview Wednesday, a senior ministry official told the Sun most maintenance and inspection concerns have been addressed with the nine dams, and insisted no one living near them should be afraid.
“They were classified once based on the inspection or audit, and at that time classified as a high risk, and those risks have been dealt with,” said Glen Davidson, the ministry’s controller of water rights for B.C.
He said the provincial government is on the verge of releasing a new report based on the “rapid assessments” undertaken on every B.C. dam since the Testalinden accident. That report will contain even more up-to-date information about the safety of local dams.   The largest of the dams considered to be of both high risk and of high consequence in the FOI is the Providence Lake Dam, which ministry documents say is more than 10 metres tall.
The dam was built a century ago to create the lake, also known as Marshall Lake, for a mine near the now-razed town of Phoenix, in the mountains east of Greenwood.
The dam, which is now owned by the fish and wildlife branch of the Environment Ministry, is experiencing water seepage “that may get progressively worse,” says a letter dated May 12.   Marge MacLean, a local history buff who works at the Greenwood Museum, said the mine’s tailings pond, which is located beside Marshall Lake, gave way about 40 years ago and it flooded the town of Greenwood. She has wondered about the same thing happening again to the community of 600 people.
“We were always very concerned about that because (the tailings pond) went before and we often wondered how safe that thing was,” she said. “It would be probably the same size as the lake and they would be within a mile of each other.”   The FOI documents said the dam was in the process of being decommissioned, but Davidson said that decision hasn’t been made yet.
Davidson added the ministry would like safety upgrades to be made to the aging dam. But he insisted people who live in the area have nothing to fear because it is a rock-filled dam, which is more stable than earth-filled dams like Testalinden.   Mark Andison, director of planning for the Regional District of Kootenay Boundary agrees that the leakage alone is not a high risk situation. He also explained that the water would probably drain down the Providence Creek drainage which enters Greenwood at the north end of the small city.  

“If there was some leaking coming from that dam it heads down Providence Creek drainage. The creek comes across the highway (at the north end of the city) and enters Boundary Creek,” said Andison. “I guess if there were a total failure of the dam it would be a lot of water coming down. But from the sounds of it, because it’s a rock-filled dam, that’s not very likely.” 

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