Project Background:
For over 20 years, residents in the Columbia Basin had been looking at ways to generate power at the Hugh Keenleyside Dam, a water storage dam, near Castlegar BC. Due to costs and environmental impacts, it was determined that installing turbines in the existing dam was not feasible.

Columbia Power Corporation (CPC) and the Columbia Basin Trust (CBT) began the process of determining whether the construction of a second powerhouse, 400 metres downstream of the existing Keenleyside Dam, would be feasible.

The Arrow Lakes Generating Station began as a proposal to construct a two-turbine facility 400 metres downstream from the Hugh Keenleyside Dam. A 1500 metre approach channel would divert water through the new powerhouse from upstream of the existing dam, and a short tailrace channel would return the water to the Columbia River. The project also included the construction of a 48-kilometre transmission line to link the powerhouse to BC Hydro’s Selkirk Substation.

In order for the project to proceed, several criteria had to be met. The project had to receive approval from the BC Environmental Assessment Office; a power sales agreement had to be in place; and a final design, to be decided through a design-evaluate-build process, had to be chosen.

Construction
After four years of public consultation, environmental approvals and studies, construction of the project began in 1999. To accommodate the project, a short portion of the adjacent Broadwater Road had to be relocated. In the fall of 1998, work began to move 740 metres of Broadwater Road. Relocation was necessary to make room for the approach channel to the new powerhouse. A public safety and traffic management plan, developed with interested local residents and agencies, was used throughout road construction.

Construction of the Arrow Lakes Generating Station began in March 1999. Removal of the tailrace plug was completed in the summer of 2001, and the removal of the intake channel plug was completed that fall.

The first unit began generating power in February 2002, and the second unit achieved commercial operation in May 2002. Both units were completed months ahead of schedule.

A Certificate of Completion under the Builders Lien Act was issued for the Arrow Lakes Generating Station on June 24, 2002. CPC and CBT took back management of the powerhouse from the design/build contractor on January 1, 2003.

The project created over 1000 person-years of direct, indirect and induced employment. At the peak of construction, over 400 workers were employed on site. Over $45 million in wages and $25 million in other spending flowed into the regional economy from the project. The project remained on budget and on schedule throughout construction.

Commitment to the Environment
Throughout construction there was minimal river sedimentation and impact to aquatic habitat, reflecting CPC’s and CBT’s commitment to environmental responsibility. Once construction of the Arrow Lakes Generating Station was complete, the project site and much of the surrounding area was restored, contoured and seeded. A new 1.4 hectare wetland area was created upstream of the project, which has become home to birds, small mammals, reptiles and fish. In all, over 67 thousand native shrubs and trees have been planted, and over 50 hectares of land have been returned to a near original state.

Environmental Benefits
Several independent studies have confirmed that the Arrow Lakes Generating Station will produce positive environmental benefits. Air quality will benefit from displacing new fossil fuel generation in the Pacific Northwest. Also, by directing water through the powerhouse instead of spilling it over the Keensleyside Dam, downstream TGP (Total Gas Pressure) is reduced.

TGP is a water quality condition that occurs downstream of dams when air bubbles trapped in water released over the dam's spillway plunge into deep water below the spillway. The bubbles are then forced into solution, which "supersaturates" the water with dissolved gases (oxygen and hydrogen) and results in TGP. Gas supersaturation affects fish by a condition called "gas bubble trauma" which occurs when the bubbles cause traumatic damage in fish tissue, similar to "the bends" suffered by human scuba divers.

Community Input
During the four year construction period, 17 members of the local community, comprised of representatives from local, municipal and regional government, local businesses, stakeholders and area residents, formed a Community Impact Management Committee (CIMC). Throughout construction, monthly meetings were held and members were given the opportunity to voice any concerns from local communities, while providing CPC with valuable community input.

Summary Socio-Economic Monitoring Report Arrow Lakes Generating Station - Final Report (PDF)