After spending hours looking for a way into this CSO tank and being unsuccessful, only finding an overflow tunnel system for it in part 1 ( @terrywayne/a-journey-into-darkness-part-1). We returned and opened another manhole. This one had a gross ladder but as soon as we got down it, we were greeted by the massive underground room!
We found it! And right away notice how much larger it is than any other CSO that I have been into! Built in 1988, this tank is shaped in a half circle rather than the usual rectangle style and holds 75,000 cubic meters or75000000 liters.
In the center of the flat wall was this structure.
I have no idea what it does, but after reading the city's information about the tank. I'm going to assume it has to do with cleaning the water before it is released into the surround wetlands and creeks.
There was no way that we could leave this room without using it for at least one steel wool shot!
We noticed an opening in a wall for a tunnel and decided to investigate.
It was a quite large tunnel with a staircase that went about 100 feet before turning to a second staircase.
At the top of the staircase was a solid metal door. With so much water running behind it that you could feel the vibrations in cement walls of the tunnel. Hearing and feeling that was enough of a que for me to end the explore. I have zero interest in being caught in there when that door opens!
This was on heck of a 2 day explore and I am so thankful to get another glimpse into this underground world! It really is incredible to see what makes our cities work. Structures and systems that no one ever thinks about. They walk on top of, or in this case play baseball on top of on a regular basis. Never giving it a thought, yet without them our city does not function! It really is wild!