Looks like it has already been mentioned. We live in one of the richest fresh water regions on this planet. No amount of climate change will change this fact.
Also as mentioned Coquitlam lake can almost double our water reservoir capacity overnight, and its already set up. The problem is that BC hydro owns the water rights. At some point the province needs to do the right thing (for the greater good) and tell BC hydro to take a hike, decommission their little hydro facility and hand the water rights to metro Vancouver. This is a logical move that should have already happened. It is a protected water shed that is hooked up already, its crazy that we flush the water into the ocean for insignificant power generation.
Secondly something like a 2 or 3 meter dam rise at Seymour would (if I remember correctly) double its capacity, but with Coquitlam lake this is not needed for many more decades anyways. But the option is there. The Capilano Seymour reservoirs are I believe over a 100 years old now.
Lastly. The Fraser River discharges a average of 3,475 cubic meters of FRESH water into the ocean per second. The lowest ever recorded discharge was 575 cubic meters of water per second. The highest ever monthly consumption of water in metro Vancouver ever recorded was in
July 2003 and was a average of 1638 million cubic liters of water per day. Convert that to cubic meters of water per second and you get 18.9583 cubic meters of water per second. Less then 1/30th of the all time record low discharge of the Fraser river. Or one 184th of the average flow. And while on the topic Fraser River flow was over 17,000 cubic meters of water per second, at Hope.
And also to be clear, Stave lake, Alouett lake, Harrisson lake, Chechalis lake, Chilliwack lake, and all the other smaller lakes hold a incredible amount of fresh water. I mean we could provide water for probably all of North America easily if we utilized all our local sources.