Finally got a shot of this odd door near Cleveland Dam in Capilano Canyon this morning. I'm not sure what it's for... presuming it's an emergency exit or something similar.
One interesting item of note in the canyon is the existence of this “door to nowhere” over looking Ring Bolt Pool and the base of Cleveland Dam. This door protects the end of a tunnel built during the construction of Cleveland Dam in the 1950’s. Originally there was a ladder from the base of the canyon up to this door to allow access for workers. Now it is an area where the dam and canyon can be visually inspected as required.
Searching “Cleveland Dam Secret Door” returned a Reddit post from a couple years ago. A commenter, who says they work for the local utility company, identified this as the “lower gallery portal” and it’s used for inspecting the dam.