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Balance of Power - The Waneta Power Project

Mar 1, 2011

When the Waneta Power Project is completed in 2015, British Columbia will have an additional 350 kilowatts of clean reliable hydroelectric power a year.

“It’s a large and very technically challenging project,” says Andrew Rule, Aecon Constructors’ contracts manager. “By the time we are finished we will have removed more than 500,000 cubic metres of overburden and rock – equivalent to about 50,000 truck loads.”

“But even though this is heavy civil work, it takes a sensitive touch. This is beautiful pristine wilderness and protecting the local plants, animals and fish is paramount.”

Originally built in 1954 just south of Trail, British Columbia, on the Pend d'Oreille River, the Waneta dam generates 450 megawatts a year, enough to power a city of 250,000 people. But even with that considerable generating capacity, the current generating plant does not use all of the available water flow at the dam, which gives the Waneta Expansion Limited Partnership a unique opportunity to add generating capacity without the need for new dam construction, new reservoir formation or additional flooding of existing reservoirs.

In October 2010, work started on the long awaited hydroelectric expansion at the Waneta dam.

Columbia Power Corporation, which is acting as a project manager for the joint venture that owns the dam, is building a second powerhouse downstream from the dam. Two large tunnels will carry the water from the dam to the new powerhouse, which will share the dam’s hydraulic head and generate power from water that would have otherwise been spilled.

A new 10-kilometre long transmission line will carry the electricity from the powerhouse to BC Hydro’s Selkirk substation.

When it is competed in 2015, the new powerhouse’s two Francis turbine units will be able to produce up to a combined maximum capacity of 335 megawatts a year of clean, renewable and reliable power.

A Major Project. A Challenging Environment.

In May 2009, the Waneta Expansion Limited Partnership chose SNC Lavalin as the preferred proponent for the design and construction of the expansion project. SNC Lavalin’s mandate included the engineering, design and construction of the facility, the installation of two turbine-generator units, plant equipment and power transformers, and the construction of a switchgear building. In turn, SNC Lavalin engaged the joint venture of Aecon Constructors and SNC Lavalin (Pacific) Inc. to design and construct the civil work and Voith Hydro to design, supply and install the water to wire work.

Almost a year and a half later, in October 2010, the Waneta Expansion Limited Partnership awarded SNC Lavalin a $587 million contract and the project was officially underway.

Aecon Constructors was able to hit the ground running, says Andrew Rule, the contracts manager.

“Typically for a job like this, you spend the first three to six months in engineering and design, but because we had a limited notice to proceed ahead of the award, we were able to get a head start on the preparation of the environmental work plans, hydraulic modelling, and engineering and design.

“So far, we have completed ninety percent of the site work and excavation designs and are well on our way for the powerhouse, intake and tunnel structural designs.”

By October, the construction crews started work on the temporary job site facilities, clearing the site, setting up security fencing, and installing site utilities.

It is a project in itself, Andrew says.

“We are going to be here for four years so calling this temporary depends on your perspective,” he says. “We are setting up our base on 10.3 hectares of land about six kilometres from the project. We will have all the contractors’ offices here as well as a carpenter’s shop, maintenance shop, and storage facilities for equipment and materials. We are also building a parking lot for the work force and employees will be taken to the site on buses.”

Work at the main site started in November with the installation of new security fencing and removal of existing structures. Site clearing and grubbing started in January.

“Basically what we are doing is creating a route to take the water from the head pond upstream of the dam through the powerhouse to the tail race downstream of the dam,” explains Andrew. “The water starts the journey at the intake structure, located adjacent to the existing dam, which houses trash racks and water control gates. It then flows through two tunnels, each one ten metres in diameter, that run from the bottom of the intake at a 17 percent grade through the bedrock to the powerhouse. The water is funnelled through the turbines, which convert the kinetic energy of the water into electric power through the generators.”

The excavation of the intake, which is 35 metres long, 24 metres wide and 40 metres deep, will start in February and the subcontractor, Emil Anderson Construction, should be completed by September 2011. The intake concrete construction will begin next year and will take 8 months to build. It will take almost another year and a half to line the intake with concrete up to 2 metres thick.

J. S. Redpath and Frontier Kemper Constructors (one of North America’s leading tunnelling contractors and a sub-contractor working with Aecon Constructors on the Capilano tunnel project) will start work on the tunnels in April. The two tunnels, each one 10 metres in diameter and 200 metres long, will be excavated using a drill and blast operation that will remove more than 55,000 cubic metres of rock. Tunnelling will be completed by next June after which the tunnels will be finished with a cast-in-place concrete liner.

The main component of the project, and the largest, is the powerhouse. Once the overburden is removed, a cofferdam will be built so that the rock can be excavated without the river flowing into the work site. The excavation for the powerhouse is expected to be completed by the end of October 2011, after which the concrete work can start.

Concrete work will take place in two stages starting with the bottom of the powerhouse up to where the turbine machinery sits. After Voith Hydro installs the turbine casing, crews will go back to do the second stage of the concrete work, encasing the casing and completing the powerhouse. The powerhouse is scheduled to be complete by mid to late 2013.

Carving a new power facility out of the granite rock that lines the Columbia River is heavy work but it takes a sensitive touch, Andrew says.

“This is beautiful pristine wilderness and environmental protection is paramount,” he says. “There are seasonal restrictions on what we can clear and when we can do work in the water. All the dredging has to be done behind a silt fence and turbidity curtains so we don’t get any sediment in the water. We are protecting some of the exotic plants found in the area. And I don’t think anybody will be doing any fishing during his or her lunch hour. The white sturgeon is a protected species and there are substantial penalties if we harm any of them.”

The Waneta Power project builds on Aecon’s legacy of successfully completed hydroelectric facilities in challenging environments and Andrew adds, “For me, the most rewarding and exciting part of this project is building Aecon’s next generation of hydro constructors to take advantage of the opportunities that lie ahead.”

Safety at Waneta

Even though both Aecon and SNC Lavalin have well-established environmental health and safety programs, the joint venture had to develop a stand alone EHS program to meet the project owner’s specific concerns.

“Relying primarily on Aecon’s Red Book, we spent months researching, developing and reviewing the new ASL-JV Health and Safety Program,” says Paul Amaro, the ASL-JV site safety manager.

The program was not only reviewed by the owner, who fully endorsed it, but also by several regulatory bodies including Worksafe BC, which enforces the provincial legislative requirements.

“Worksafe BC did have a concern about protecting hazardous conditions when the workers left the site,” recalls Paul. “We pointed out that our job analysis risk review card has a section that specifically asks if all hazardous conditions have been removed or protected prior to leaving the area and that satisfied the inspectors.”

Since the project began in October 2010, more than 350 workers (including visitors, suppliers and owners representatives) have taken the ASL-JV safety orientation, 48 workers have been trained in fall protection, and 16 workers have been trained in Level 1 first aid. Supervisors have completed more than 550 JARR cards have been completed and there have been more than 58 site inspections.