Following Jean Cass's excellent history of the Rivelin Tunnel, published here in August 2010, hildweller posted a comment and a photo of the tunnel exit. His last two sentences referred to the tunnel’s entrance, somewhere in the wood behind the Ladybower Fisheries Office.He wrote “Has anyone ever seen this portal I wonder. I’m afraid exploring up there is beyond me nowadays.”
Please see the attached photo, taken from the woods behind the Fisheries. I was surprised to find that the Rivelin junction is open to the elements, outside the Valve House. The flow from right to left is the gravity fed flow from Derwent to Bamford filters. The flow towards the bottom right of the photo is Sheffield’s supply, about to enter the Rivelin Tunnel.