Forums Forums Wirral History : Chasing the Past Wirral History Overflow Tunnel Borough Rd 1930s

Other schemes on the Wirral side (in chronological order) were Wallasey Interceptor Sewer, Green Lane IS (Birkenhead), and Beaconsfied South IS (which took flows down to Dock Road South in Bromborough).
As for Beaconsfield North, I can't remember what happened to the flows after they left The Dell pumping station (may have gone to Beaconsfield South outfall off the end of Dock Road South?).

I have a couple of comments on the original topic of the sewer overflow.

I remember that the manhole chambers around the top of Everest Rd / Victoria Park were amongst the deepest on Wirral - unfortunately I can't precisely recall the depths, but I think they are 15m+.

This whole area was modelled on a computer in the early 1990s which required an accurate idea of pipe sizes, manhole depths, catchment areas etc. The accuracy of the computer model was verified by collecting actual flow measurements in the various pipes during heavy rainfall, together with rain gauge information collected from several nearby roofs (one was on the Crosville Depot on New Chester Road).

The reason for the modelling was the design of a new "interceptor" sewer to carry flows from the end of St Paul's Road next to the roundabout and then south beneath the Rock Ferry / New Ferry bypass to the pumping station at The Dell. This scheme was called "Beaconsfield North Interceptor Sewer" and was part of the MEPAS (Mersey Estuary Pollution Alleviation Scheme) initiative to clean up the river Mersey.

Other schemes on the Wirral side (in chronological order) were Wallasey Interceptor Sewer, Green Lane IS (Birkenhead), and Beaconsfied South IS (which took flows down to Dock Road South in Bromborough).
As for Beaconsfield North, I can't remember what happened to the flows after they left The Dell pumping station (may have gone to Beaconsfield South outfall off the end of Dock Road South?). The outfalls at Tranmere and the Dell (extended to mean low water spring tides) were retained as overflows in case the system was 'beaten' during rain storms. I think all the drainage from the Rock Park frontage may have been picked up (previously it just went out part way across the foreshore to discharge)and taken via tunnel back to the main Interceptor Tunnel under the by-pass.

That was how the design was being progressed but I don't know what was finally actually constructed, but I suspect it wasn't too different.

Up until a few years ago I had access to A0 size linen original "OS" plans of Wirral from about 1900 on which had been inked in all sewer lines, pipe sizes, invert and cover levels etc. I could have looked at these and maybe given a more definitive response but I do seem to recall the bottom of Everest Road/Borough Road being important - there may have been a weir/overflow there with excess flows diverted towards the Mersey via the Everest Rd/Victoria Park/St.Pauls Road route (your first photo in your first post)- I remember someone going down that manhole and the safety rope on the harness nearly ran out (deeper than thought); unfortunately I can't recall precise details of the findings.

I used to have a nice coloured drawing on linen of a sewer vent along Borough Road (looked like a cast iron lamp column, but the top was open to the atmosphere) - I think some of the vents are still in-situ.

21 metres depth wouldn't surprise me, I thought I'd better under- rather than over-estimate the depth in my original post. I remember a flow monitor going in to that deep manhole to record storm flows - this of course resulted in one of the driest spells for a long time, and when it did rain all the equipment got washed away (and probably out under Tranmere Oil Terminal outfall).

Which manhole was it where the rope nearly ran out? Not Borough Rd. surely?

I know where the original plans went to, if I get a chance in the next couple of weeks I'll try and see if they're retrievable.