Garibaldi Lake
You can estimate the volume of the lake by multiplying the Surface Area of the lake by the depth of the lake. We can estimate that the shape of the lake is close to a rectangular shape.
The volume formula of a rectangular prism is W x L x H which is basically the area of the base x height.
The surface area is given : 9.94 
First, convert the surface area to m:
then multiply it by the height or depth, and convert the unit to litres because we are measuring liquid.
So by estimation, the volume is 1200000000000 litres, so we can write it as 1.2 x 
How much water does the Barrier contain behind it in the lake?
To find how much water the Barrier contains, we multiply the surface area by the depth. The surface area is in Km and the depth is in m, so we have to first covert the surface area to m.
and then, we do SA x H
Water is measured in Litres, so we change this to Litre.
So in total there are about 1182,860,000,000 litres of water in the lake. Or we can write it as 1,18286 x
If the Barrier collapsed, the water from the lake would flow out, and flood nearby towns and cities, such as town of Squamish, and possibly Howe Sound and Vancouver Island. This would also affect the Cheakamus and Squamish Rivers. The barrier is affected by wet weather or earthquakes.
I think more than half of the water in the lake would flow out, it would be enough to flood nearby towns and rivers, it would do great damage to it’s surroundings. According to this article by Michael Powel, Steve Quane from Quest University stated that the water flowing out of the Garibaldi Lake would be 120 metres high, if the Barriers were to collapse in an earthquake. Knowing that the surface elevation is 1484 m, and the volume is more than 1 trillion litres, the power would be 200 times the energy of the bomb in Hiroshima.
References:
Article by Michael Powel: http://www.squamishchief.com/news/garibaldi-lake-a-ticking-time-bomb-1.1753732
Wikipedia: https://en.wikipedia.org/wiki/Garibaldi_Lake
