Whitehorse Rapids Generating Station


Description: This photo is an aerial view of the Whitehorse Rapids Generating Station in the beautiful capital city of Whitehorse Yukon! The photo was taken in late July when water levels are at their highest on the Yukon River and significant spill takes place at the dam.

Construction of the facility was completed in 1958. The original powerhouse building hosts three units and is located at the bottom right of the picture. A fourth unit was installed in 1985 in a new powerhouse and can be seen just to the right of the spillway. The facility operates under approximately 18 m of head, with a maximum turbine flow of 240 m³/s for an installed capacity of 40 MW. There is water storage for winter generation approximately 30 km upstream on Marsh Lake with a storage range of 2.5 m (within the natural range of the lake). Storage is limited and as such it still results in significant spill during the summer months. Winter generation only averages about 25 MW due to limited water availability.

The facility is also home of the longest wooden fish ladder in the world! The fish ladder is designed for chinook salmon passage and has been operating since 1958. It is seen on the left side of the river extending up to the main dam. The river wide weir some distance downstream of the spillway was constructed to direct salmon to the entrance of the fish ladder.

Description: Cette photo est une vue aérienne de la centrale de Whitehorse Rapids dans la belle capitale de Whitehorse au Yukon! La photo a été prise à la fin de juillet, lorsque les niveaux d’eau sont à leur plus haut sur le fleuve Yukon et qu’un déversement important a lieu au barrage.

La construction de l’installation a été achevée en 1958. Le bâtiment original de la centrale électrique accueille trois unités et est situé en bas à droite de l’image. Une quatrième unité a été installée en 1985 dans une nouvelle centrale électrique et peut être vue juste à droite du déversoir. L’installation fonctionne sous une hauteur de tête d’environ 18 m, avec un débit de turbine maximal de 240 m³/s pour une puissance installée de 40 MW. Il y a un stockage d’eau pour la production hivernale à environ 30 km en amont sur le lac Marsh avec une aire de stockage de 2,5 m (dans l’aire de répartition naturelle du lac). L’entreposage est limité et, à ce titre, il en résulte encore des déversements importants pendant les mois d’été. La production hivernale n’est en moyenne que d’environ 25 MW en raison de la disponibilité limitée de l’eau.

L’installation abrite également la plus longue échelle à poissons en bois au monde! L’échelle à poissons est conçue pour le passage du saumon quinnat et fonctionne depuis 1958. On le voit sur le côté gauche de la rivière s’étendant jusqu’au barrage principal. Le déversoir large de la rivière, à une certaine distance en aval du déversoir, a été construit pour diriger les saumons vers l’entrée de l’échelle à poissons.

(Ceci a été traduit automatiquement)

Submitted By: David Morissette

City: Whitehorse

Region: Territories

Benefits to society [Translate]

The Whitehorse Rapids Generating Station was built in 1958 to supply electricity to a growing Yukon population especially in Whitehorse. To this day, it remains one of the most important pieces of infrastructure of Yukon, providing approximately 40% of the total electricity in the territory. It provides Yukoners with reliable energy at some of the lowest cost in the north.

The facility provides significant recreation opportunity within the city. The upstream headpond Schwatka Lake is a popular recreational area for boating and swimming, and also serves as the local floatplane base. Downstream of the facility, the Yukon River flows through the city and provided good recreation opportunity. It includes fishing, kayaking and walking trails along the river.

Recreation on the Yukon River is done in accordance with Yukon Energy public safety program and adequate development and signage had been developed over the year. The Whitehorse dam is a landmark within the city of Whitehorse and residents enjoy walking and biking along the numerous trails near the facility and the river. It also provided very good learning opportunities for students who can visit the facility and learn more about renewable energy and hydropower development. A visitor center at the fish ladder with a viewing chamber is also open during the summer months to learn more about salmon migration on the river.

Economic benefits [Translate]

The development of the Whitehorse Rapids Generating Station has been instrumental in the economic development of Yukon and its capital city. It provides long term stable and reliable energy to yukoners, at some of the lowest costs in the north. The location of the site directly in Whitehorse provided favorable economics for the project since only very short transmission lines was required to send electricity to Whitehorse.

It also contributed significantly to the industrial development of Yukon, especially mining development and associated infrastructures. The available energy allowed mines to go ahead with development and operation as a result of construction of the hydro facility. The importance of the facility is even higher today since renewable energy is in limited supply in Yukon. Producing electricity locally in Yukon has allowed expenditures to stay within Yukon and booster local economy for decades. The facility remains is an essential to Yukon and will remain for many decades to come.

Technical merits [Translate]

The construction of the Whitehorse Rapids Generating Station presented numerous challenges, especially in a remote northern environment with limited local resources in the 1950’s. The construction of the Alaska Highway during World War 2 provided road access to Yukon. The road was however narrow, rough and slow. As such transporting equipment and materials to Whitehorse for construction of the dam presented significant challenges and was time consuming.

The main dam and spillway are built on basalt, which is heavily fractured. The rock outcrop is limited to the main river bed and thick alluvial deposits cover the sides of the river as a result of glacial action in the past. Significant foundation treatment took place and long term monitoring of the dam performance has been key to its long term stability and integrity. The construction of the dam and creation of Schwatka Lake upstream also allowed to provide a safe and reliable unlimited groundwater supply to the city of Whitehorse.

The fish ladder that is adjacent to the facility is the longest wooden fish ladder in the world. It provides reliable upstream migration to the longest chinook salmon migration in the world on the Yukon River (close to 3000 km). A fish hatchery was also created following the construction of the dam. The fish hatchery remains operational to this date and has provided benefits to the salmon stocks of the upper Yukon River.

Historical background [Translate]

Construction of the facility began in 1957 and was completed in 1958. It constructed for Northern Canada Power and Commission (NCPC) at a cost or $7.2 million. Poole Construction built the facility employing approximately 80 people on the project. Design of the facility was led by an electrical engineer, W.I. Lowe, from the Montreal Engineering Company. The decision to build the dam was based on a growing Whitehorse that needed more electricity than a local small power plant provide. Diesel generation was also considered, but the large potential of the Whitehorse Rapids was identified as the most attractive option. Little environmental studies took place prior to construction.

At first, the facility had 2 turbines for a total capacity of 12 MW. With growing demand especially from the Faro Mine 250 km north of Whitehorse, a third turbine was installed in the original powerhouse in 1969 bringing the total installed capacity to 20 MW. A control structure at Marsh Lake 30 km upstream of the facility was also constructed to provide water storage for increased winter generation. In 1985, a fourth turbine of 20 MW was added in a new powerhouse building, largely to provide power to the growing Faro mine.

In 1997, a fire completely burned the original powerhouse. The three turbines survived the fire and remained largely intact and are still operational to this date in a new building. The facility is now nearly 70 years old and remains in good shape. It continues to operate safely and reliably.

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