Estimate how much water is behind the barrier
To answer this question we first must find the volume of the Lake. When I looked for the dimensions I found that the surface area is 9.94km2 and the average depth is 199m2. We have to make everything the same unit (Liters).
9.94km/1m x 1000m/9.94km = 9940m
9940m/1L x 1000L/1m = 9940 000 L
9940 000 L x 119 m = 1 182 860 000 L
The volume is 1,182,860,000 L, 1 L of water = 1 Kg of water = 1 m3
The lake is 15.7 m deeper than the barrier. So 1 182 860 000 Kg = 75 341 401.27 Kg is about how much water is behind/against the barrier, and nothing bellow.
The measurement I have done is not fact due to the depth being inconsistent and not a 119m2 all over so its not the exact measurement.
If the barrier faulted, what do you think would happen? Consider how much water would escape, and what kind of power is the escaping water equivalent to?
Well, have you ever been at a beach and the waves were a bit stronger than normal and its knocks you over when you’re standing up? Yeah times that by like a million. It would leave a path of destruction! so like a tsunami.
Link
https://en.wikipedia.org/wiki/Garibaldi_Lake