It has been almost 20 years since Trail has drawn water for municipal use from an open water source known as the Cambridge reservoir in the area of Violin Lake.
Now, the city is investigating measures to decommission the Cambridge Dam, a barrier to water drawn from Violin Lake and stored in the reservoir, historically known as the mill pond.
“The dam is in good shape and kept up to specifications,” said Warren Proulx, Trail’s working foreman and engineering technician. “But we want to eliminate this responsibility because it no longer has value to the city.”
In 1994 Trail established the Columbia River as the city’s main water supply source and built modernized water treatment facilities, in part due to the 1990 community outbreak of giardiasis (beaver fever) a parasitic gastrointestinal infection traced to inadequately treated drinking water pulled from the reservoir.
After the treatment plant using the Columbia River was completed, the city decided to maintain the infrastructure of the Cambridge Creek/Violin Lake water system as a back up water supply.
However, four years later, Trail’s conditional water license was cancelled by the Ministry of Environment (MOE), under the Water Act, because the water system was deemed no longer actively used for domestic water supply purposes.
The reservoir is still active as a man-made lake (on private property) and the city is responsible for monitoring the dam.
However, in light of increased costs and tightened government regulations to maintain privately owned dams, council has backed the decision to decommission the Cambridge Dam, said Proulx.
“There is a cost to inspect and maintain the dam,” he explained. “It would save us time and time is money,” Proulx continued. “And it would release the city of any liability if the dam ever burst.”
Since the breach of the privately-owned Testalinden Creek Dam eight kilometres south of Oliver in 2010, which caused enormous debris and mud torrent that impacted homes and agriculture in the area, the ministry has stepped up efforts to monitor B.C. dams to mitigate loss of life and damage to property and the environment in cases of a dam break.
According to the MOE, the Cambridge Dam is classified as high consequence, meaning if it ever breached, downstream impacts would be devastating.
“There is no fear of that right now,” said Proulx. “Other than it being beautiful up there, we don’t need it, so let’s get rid of it.”
Proulx accompanied a team of engineers to the dam last week and expects an expansive report in the next six weeks, detailing how the dam can be retired and the reservoir drained according to ministry regulations.
“We don’t know what the costs will be,” he said, adding, “but it will include reverting the area back to its natural state.”
Once an engineering plan and costs for decommissioning the dam are determined, the project will be submitted to council for consideration in the 2014 capital budget.
Since the 1920’s the area around Cambridge Creek and Violin Lake was the primary source of water to half of the city’s annual water demand.
At that time, the city purchased the lands, and over the decades, built infrastructure to draw water from creeks, lakes and reservoirs in that area.
Included was an intake on Cambridge Creek, with a pipeline to reservoirs and a chlorination plant, with the city maintaining water licences for diversion use and storage of the water in the area.