Sewers: technical term for ...

[N_Cook]

Holding "tank" /catchement chamber/ interceptor? back in the Victorian era and brick and clay pipe sewers era. The stooping-high chambers designed for holding extreme roof-run-off rainfall in volume, that would otherwise surcharge the main sewer system if allowed into it immediately if larger pipes/sewers were used and rhen would overwhelm sewage works. With frog-up for boot-grip, brick plinths running each side for stoop-walking along, rather than running sewer type slippery/sloping benching and sewermen then having to walk in the middle foul sewer recess. Built in the days before climate change and more monsoon-like rainfall events.

[The Natural Philosopher]

Oh a billion years old?

Wow!

[Bob Eager]

In the Brighton sewers, they call them 'overflow chambers'. I did a tour once, but as it happens saw a map last week.

[Tim Lamb]

In message <smm34m$sg3$ [e-mail], N_Cook [e-mail]> writes

Our second house (Edwardian) had a *soft water well*. Big brick underground chamber for gathering rainwater. Presumably pumped to an indoor tank for bath and toilet use. Pipes at high level to soaks when full. I don't know what they used for drinking water but an older house next door had a well.

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[N_Cook]

Ta for that, googlable term. "During a storm event, heavy or prolonged rainfall can rapidly increase the flow in a combined sewer and cause it to become overwhelmed. Storm overflow chambers are designed to release excess storm water into rivers or the sea when this happens." Explains the upper level 8 inch clay pipe assumed to be a disused entry pipe as no sludge discoloration at all, but is probably the upper level output pipe to the local river. So the chamber is roughly sorting the foul heavier stuff at the base outgoing to the sewer system , slowly, and the upper level relatively clean water but plus toilet paper out to the river.

[newshound]

My second (Georgian front but tacked on to older older cottages) had some sort of chamber underneath the patio behind it, which was about four feet above ground floor level. Evidently rainwater was still being fed into it, although I never quite figured out how, because you could hear it running in during rainstorms. The (below ground level) overflow probably ran next door to a lower property that was originally part of the same building. (In fact our foul drain simply ran into an old well on that property too, as the property developer who bought it discovered when he went to develop it).

There was a "classical" cast iron lift pump mounted on the front of the chamber, but with no innards. I'm not sure if that was the original route for extracting water (it would have been convenient for the adjacent kitchen), or whether it had been added recently as a decorative feature.