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A blueprint of the facility overlaid on an aerial photograph
Similar to the Cathedral, the Greenhill CSO tanks are designed as a storage mechanism for the Woodward Ave waste water treatment plant. The CSO holds excess storm/sanitary runoff until it can be properly processed at the WWTP. Without the CSO, a heavy storm would overburden the WWTP and send sanitary waste directly into the Red Hill Creek.
The Greenhill CSO is supplied by a combined 3×3.5m conduit under Fennel Ave on the east mountain, that carries combined sewage to one of Ontario’s deepest sewer dropshafts, below which it is intercepted at the end of Greenhill Avenue. A series of pumps at the interceptor send regular flow levels down to the Woodward WWTP— overflow is routed into two (or three?) cylindrical tanks, and overflow from those flows out into the Red Hill Creek.
It was through this outflow that we entered the system, having found all of the manholes in the park frozen shut. Dave and I had hip waders, so we volunteered to wade up the freezing cold creek and through the overflow drains to try and pop a manhole open from below.
Image may be NSFW.
Clik here to view.
Image may be NSFW.
Clik here to view.
Image may be NSFW.
Clik here to view.
Image may be NSFW.
Clik here to view.
The construction of the drain was not as exciting as some I have been in, but for some reason— maybe due to the sanitary nature of the overflow, or the geographical location of the drain— the mineral formations were unusually large, and the colors especially vibrant.
Image may be NSFW.
Clik here to view.
Image may be NSFW.
Clik here to view.
Image may be NSFW.
Clik here to view.
Image may be NSFW.
Clik here to view.
We were able to get a peek through the overflow grilles at the tanks, but found no way of accessing them from where we were. We spent a bit of time poking around the park, and eventually found the covers to the interceptor and pump rooms, but these were also inaccessible. We walked a way up Greenhill Ave, thinking that maybe we could follow the incoming flow from the dropshaft into the tanks.
The manhole we found open has some history— this was the place where, apparently, some kid a few years ago was messing around in the drain during heavy rains, slipped, and was swept down into the interceptor and killed. This is also where Kyle and Mel were caught by the police earlier this year, after a woman saw them near the drain and reported it. Needless to say, we proceeded with caution.
There was a strong current, with water about 8 inches deep, and a slippery floor. The slope towards the interceptor was steep enough that I knew, should one of us fall, we’d probably not be able to stop ourselves. I have no idea how the Greenhill interceptor functions, but if it’s anything like the Locke St. interceptor, it’s not something I’d like to fall into.
The wet air rushing at us came from uphill, towards the escarpment, accompanied by a loud rumbling. We walked towards the noise as the fog grew thicker. After maybe 100 meters, we came to one of the most beautiful sights I’ve ever encountered underground (unfortunately, there was too much water in the air for me to risk bringing out my camera).
Ahead, through a stone arch, was a dropshaft leading up into the dark, to the level of the escarpment roughly 300 feet above. Water fell in thick sheets, hitting the shallow basin at the bottom of the shaft with such force that we couldn’t hear eachother speak, even twenty feet away from the arch. We didn’t dare get closer, though I wish now we had. Visibility fell significantly with every step, so I suspect that we wouldn’t have known we’d arrived until we walked into the waterfall itself. I’d like to go back sometime, in drier weather, and try and photograph the engineering around the base of the shaft. It must have taken some clever planning to handle that much water at such velocities without experiencing significant erosion.
After reaching the ladder, we tried inching our way further down the passage, but the grade grew steeper and the floor got slipperier. We elected to be smart, and come back some other time with a rope.
Followup
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This image suggests a second tank, to the north, under the baseball diamond
I worked a little wizardry and merged the city of Hamilton’s GIS data onto a satellite image of the area, and found an unusual dark spot— four fair-sized drains seem to end under the baseball field, to the north of the area we’d been exploring.
I’d also like to return in drier weather and check out the dropshaft better, and attempt (maybe with the help of rope) to work my way down into the interceptors themselves— maybe gaining access to the pump rooms and tanks proper. This is certainly a complex facility, that calls for much more investigation.