How a Dam Works

The Whitehorse Dam (officially known as the Whitehorse Rapids Generating Facility) is an interesting place to visit. If your class wants to come for a tour, please call beforehand and we will arrange a time that works best for both you and our employees.

If you study our facilities map before you come, it will help you understand how the different parts of our facility work together to make electricity.


Facilities Map

  1. Turbine #4, often referred to as the Fourth Wheel
  2. Spillway – water not needed to produce electricity is spilled into the Yukon River
  3. Fishladder – allows migrating salmon and other species of fish to travel past the dam
  4. Fish weir – directs fish towards the fishladder
  5. Fish screens – also help direct fish towards the fishladder
  6. Underwater canal – another aid to direct fish towards the fishladder
  7. Turbines #1, 2 and 3
  8. Switching station – sends electricity to various communities
  9. Back up diesel generators
  10. Diesel storage tank
  11. Substation – gives electricity a voltage boost to help it travel along power lines Yukon Energy's award-winning administrative building

Dam

One of the first things you'll notice if you come to visit is our dam. It's a huge steel, dirt and concrete structure that holds back the water from Schwatka Lake. It has to be pretty strong, since it holds back between 8 and 13 billion litres of lake water. The dam has flashing lights to warn airplanes of its location so they don't fly too low. In the summer and fall, when we sometimes have more water than we need to make electricity, we let some of the water from the lake spill over a part of the dam called the spillway (number 2 on map).

Power Canal

Our facility is built in such a way that most of the water from Schwatka Lake moves into a long and narrow area called a power canal. There are trash gates in the canal to catch any fallen trees or other things that shouldn't be in the water. If we allowed them to get into our turbines, it could cause a lot of damage. There are also a series of log booms in the canal that make the water calm, thus stopping the banks of the canal from eroding.

Turbines

From the power canal, the water falls through huge underground pipes and hits the blades of our four turbines, making the blades turn. Three of the turbines are at the end of the power canal (number 7 on map) and our newest turbine, which we call the Fourth Wheel, is at the top of the canal (number 1 on map).

The turbine blades are attached to generators that make electricity. Once the water hits the turbine blades, it flows back into the Yukon River.

Find out more about how electricity is produced.

Diesel Generators

We use water to produce almost all of our electricity, with a small amount of power coming from our two wind turbines on Haeckel Hill near Whitehorse. Once in a while we may have to use diesel fuel instead of or in addition to wind and water. For instance, if some of our equipment breaks down in winter, using diesel is our back-up plan so your homes can stay warm and you can still turn on your lights. We have seven diesel generators at our Whitehorse plant (number 9 on map). We also have a big diesel storage tank (number 10 on map) that holds enough fuel to keep all our diesel generators running one full day.

Substations and Switching Stations

Once electricity is produced, it moves through power lines to something called a substation. Substations are fenced-off areas that have lots of wires and power transformers (number 11 on map). They give electricity a voltage boost (voltage is the strength at which electricity moves) to help it travel along power lines to Yukon communities. Across the Yukon River is something that looks almost like a substation, but it doesn't have the ability to boost voltage. It's called a switching station (number 8 on map) and it sends the electricity to the various communities it needs to go to.

Fishway

When the dam was built, salmon and other fish couldn't travel this part of the river like they had in the past, so some special equipment was built to help them. A wooden fish ladder (number 3 on map) was made that allows the fish to move between Schwatka Lake and the part of the Yukon River below our dam. There's an interpretive centre at the fish ladder that tells the story of the migrating Chinook salmon, plus there are underwater viewing windows and TV screens so you can see the fish as they swim by. It's a great way to spend some time in the summer!

Find out more about the fishladder.

Fish screens and weir

There are other things that also help the fish find their way past the dam. Special screens are put in the water in the summer time to stop the fish from swimming into the water that's just run through our turbines (number 5 on map). There's a concrete dam or weir that also makes sure the fish swim towards the fish ladder and not our turbines (number 4 on map). There's even a special underwater canal (number 6 on map) that helps the salmon find their way.

Award Winning Building

Before finishing your tour, don't forget to take notice of our new office building (number 12 on map) that was built after our old one was destroyed in a fire on October 30, 1997. The new building has won a special award because the way it was designed helps us use as little energy as possible.