Garibaldi Lake is located north of Squamish and south of Whistler. Two of the nearby volcanos have created a blockade (a dam) for the lake due to their lava flows. The lava dam is over 300 m thick and about 2 km wide where it encloses the lake.
In math class we were asked to find how much water the lake contained, using the skills we have been learning in our measurement unit including measurement and conversions. The exact questions we had to answer were:
“How much water does the barrier contain? If the barrier faulted, what would happen? How much water would escape, and what kind of power is the escaping water equivalent to?”
I started off by finding some basic information about the lake. I found that it had a surface area of 9.94 km^2 and had an average depth of 119 m. I decided to use these two measurements to find an approximate calculation of the lake’s volume. My calculation would not be exact because the lake has an irregular shape and is not a perfect prism or cone.
How Much Water does the Barrier Contain?
I started off by converting the surface area to square meters so I could have the same units that I have for the depth of the lake.
Surface Area = 9.94 km^2
Surface Area = 9,940,000 m^2
Surface Area = 9.94 • 10^6 m^2
From there I was able to easily find the amount of water the lake contains by using the formula for finding volume.
Volume = SA • Average Depth
Volume = (9.94 • 10^6 m^2) (119 m)
Volume = 1,182,860,000 m^2
Volume = 1.2 • 10^9 m^3
From there all I had to do was convert the volume in cubic meters to liters, because water is measured in liters.
1 m^3 = 1000 L
1.2 • 10^9 m^3 = 1.2 • 10^12 L
So to answer the first question “How much water does the barrier contain?” The barrier contains approximately 1.2 • 10^12 L of water.
If the Barrier Faulted what would Happen?
If the barrier faulted the amount of water that would escape depends on where the barrier faulted. If it faulted near the bottom, or at the bottom, for example not all of the water from the lake would escape. This is because the floor of the lake is not perfectly even, so some of the water would stay stuck in pools were the ground dented inwards. Another factor that would contribute to this is also that the ground isn’t angled towards the barrier, so once the pressure decreased some of the water would just stay where it was. However, if the barrier broke further up near the top not a lot of water would would escape because anything below the fault would be unaffected and just lay dormant.
If the barrier broke it would definitely effect it’s surroundings and environment as well, because it is filled with so much water. The water would damage the surrounding trees and plant life, it would disrupt nearby animals and their habitats, and it would also greatly effect the people that live nearby in Squamish. Steve Quane from Quest University’s research confirms that if the barrier ever breaks it would be catastrophic for the people in Squamish.
What Kind of Power is the Escaping Water Equivalent to?
Steve Quane also talks about what the force of the water would be if the barrier faulted. He says “The potential energy at 1,400 meters elevation, of 1 trillion liters of water, is 200 times the energy released by the bomb on Hiroshima”. That means that if the barrier were to fault the force from the water would be 200 times the energy released by the bomb on Hiroshima!!
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SOURCES:
https://en.m.wikipedia.org/wiki/Garibaldi_Lake
http://www.squamishchief.com/news/garibaldi-lake-a-ticking-time-bomb-1.1753732
REFLECTION:
Overall I thought it was very interesting to learn more about the Garibaldi Lake and the lava dam. I thought is was really cool that I got to put my measurement and conversion skills into use to find more information about the lake. Overall if I was to do this project again I would measure the volume of the lake using the formula for the volume of a cone, because when I think about it more the lake is surrounded by mountains so it would most likely go to a point near the bottom and the sides would come up on an angle towards the top (like an upside-down cone).
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