Transmission (edit: subtitled SSFD (slip, slide and fall don)) is part of a storm water drainage system in the North of Sheffield. The section reported here is approximately one kilometre in length, leading from the outfall into the Don to the drain’s main feature - a large waterfall. Parts of this system were built towards the end of 1952, with some sections possibly being older.
The discovery of this drain was a proper team effort. After I initially came across evidence of the tasty looking slide section seen here (I’m being intentionally vague about my sources on a public forum), @tallginge did some work on locating a possible way in. One quick recce mission using his finely-honed drain talents and he had located a likely lid. We both reconvened with @Esoteric Eric who then took the lead, persisting down some really stoopy RCP towards what the conclusion of this section. We were all slightly taken aback, not only when @tallginge’s lid selection took us immediately to the exact section we were hoping for but also, a couple of hours later, when we were treated to the impressive man made underground waterfall.
I’ll take this from the furthest northern point to the furthest south, even though things didn’t quite proceed in that order.
So, firstly there’s a relatively unnasuming RCP that outflows to the Don. This is almost completely covered by a flap - I stuck my camera under to get a photo of the river beyond. The water level in the pipe was the same as the river itself, and this pipe was stocked full of healthy looking fish. Always good to see.
A small chamber. A lot of the ironwork in here has seen better days! Left leads towards the outfall whilst the RCP heads under the canal...
... and then up the other side of this slide. There’s a deep cushion pool at the bottom of the surface water ramp. This was what we had aimed to see...
To be honest if this had been the end of it we would have been satisfied, but there was more... the remaining walk was long and fairly uneventful for the most part, except for some nice looking chambers....
There were lots of pipes poking in from each side along the route, most of which we bypassed in favour of making progress as speedy as possible...
For the most part, @Esoteric Eric had gone on ahead. The main pipe had become progressively more stooptastic, and me and @tallginge started to wonder why he was still going... however, stopping to stretch our backs we realised that it was probably the deafening sound of roaring water ahead that was leading him on. Interesting! Just after this chamber we found the source of the sound...
As Eric commented, this but is probably one of our best (and least expected) finds in Sheffield...
A fast flow of water plummeted down a 10ft drop from a pipe above into a pit ahead of us that, measurement with a fully extended tripod suggested, was really fucking deep. To the right was some kind of slide, with a wooden barrier and metal handrail. Plants were growing through and you could just see the faint glow of the night making its way in from outside. It wasn’t long before someone found the way out for a bit of a pose...
The waterfall begs the question, if this is a storm water overflow and there hasn’t been any rain for at least a week, why is the flow so fast? There’s no sign of any buried rivers or streams nearby on archive maps, so this question can probably only be answered by pushing on further another time...
Anyways, after taking our pics, finally it was time to make our way out. Both @tallginge and @Esoteric Eric got some great photos around this bit which they may or may not want to add to the thread...
And back home we went. There’s further to go here, but this was enough for one evening. Hidden underground man-made waterfalls for the win...
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