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Manhole Chamber Query

Does what it says on the tin
TurboukToo2
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Manhole Chamber Query

#210579

Postby TurboukToo2 » March 27th, 2019, 9:21 am

Hi

We are looking to put down a 5.4m * 3.5M concrete hardstanding for a a shed/gazebo structure to sit on. In preparing the ground we have uncovered a 700m * 700m iron manhole cover. We opened it up and below was a rather large chamber lined by 8 layers of bricks (good condition) plus a then a further drop to a wider area with a large pool of standing water in it - no smells or signs of toilet paper etc so guessing not a foul drain. Approx 2 meters depth overall I would guess. The manhole cover sits away from the proposed hardstanding location by approx 250mm so no question or need to build directly on top of it.

Couple of questions as not sure where to start:

How would I get information on the purpose this drain?
Is the standing water anything to be concerned about?
Does the proximity to the proposed location of the hardstanding mean seeking approvals or put any kind of stress on the chamber structure?

Not even sure if there is anything to worry about at all to be honest but it was a bit of a surprise finding such a large chamber under the flower beds!

Thanks

sg31
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Re: Manhole Chamber Query

#210592

Postby sg31 » March 27th, 2019, 9:43 am

My first thought is that it may be an old well. Much more likely in a country area.

I had a C16 cottage in Lincolnshire many years ago and found something similar which did turn out to be the well for the cottage.

dspp
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Re: Manhole Chamber Query

#210606

Postby dspp » March 27th, 2019, 10:15 am

It may well be an old cess pit. I have previously excavated one and it was absolutely clean and smell free, yet I know it had been in long use.

regards, dspp

Dod101
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Re: Manhole Chamber Query

#210617

Postby Dod101 » March 27th, 2019, 10:37 am

My money would be on a well. I live in an extended 19th century cottage and like others on my road, it had a well. I think mine has been fiiled in but there are still several around. Can you use a plumbline to see how deep the standing water is?

Dod

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Re: Manhole Chamber Query

#210625

Postby pochisoldi » March 27th, 2019, 10:53 am

Would it be worth pumping out the water, to (1) see what's in the hole, and (2) to see if it refills with ground water?

redsturgeon
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Re: Manhole Chamber Query

#210646

Postby redsturgeon » March 27th, 2019, 11:43 am

Soakaway?

John

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Re: Manhole Chamber Query

#210651

Postby kempiejon » March 27th, 2019, 11:52 am

Could one re-purpose it as a wine cellar, grey water reservoir, nuclear bunker, a zombie apocalypse hide away, underground lair, bondage dungeon what a useful find.

sg31
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Re: Manhole Chamber Query

#210807

Postby sg31 » March 27th, 2019, 5:06 pm

redsturgeon wrote:Soakaway?

John



Most of them are filled with rubble when they are built.

redsturgeon
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Re: Manhole Chamber Query

#210827

Postby redsturgeon » March 27th, 2019, 5:57 pm

sg31 wrote:
redsturgeon wrote:Soakaway?

John



Most of them are filled with rubble when they are built.


I'd agree but I just uncovered on in my garden, empty with a concrete roof to prevent collapse.

John

TurboukToo2
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Re: Manhole Chamber Query

#210847

Postby TurboukToo2 » March 27th, 2019, 7:33 pm

redsturgeon wrote:
sg31 wrote:
redsturgeon wrote:Soakaway?

John



Most of them are filled with rubble when they are built.


I'd agree but I just uncovered on in my garden, empty with a concrete roof to prevent collapse.

John



I did wonder if was a soak away too. How did you determine yours actually was a soak away especially in the absence of the rubble usually used in them?

I think I will need to get a drain firm to take a look. The standing water maybe be fine but I can other pipes come into the chamber - I think from drainpipes - and if it’s a drain then I would expect it to ...drain.

redsturgeon
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Re: Manhole Chamber Query

#210850

Postby redsturgeon » March 27th, 2019, 8:03 pm

TurboukToo2 wrote:
redsturgeon wrote:
sg31 wrote:

Most of them are filled with rubble when they are built.


I'd agree but I just uncovered on in my garden, empty with a concrete roof to prevent collapse.

John



I did wonder if was a soak away too. How did you determine yours actually was a soak away especially in the absence of the rubble usually used in them?

I think I will need to get a drain firm to take a look. The standing water maybe be fine but I can other pipes come into the chamber - I think from drainpipes - and if it’s a drain then I would expect it to ...drain.


The pipes running into it from my down pipes.

John

malakoffee
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Re: Manhole Chamber Query

#210855

Postby malakoffee » March 27th, 2019, 8:46 pm

Another possibility : some sort of ground water attenuation structure.

i.e. in days of old people tended not to built in places that flooded or had a high water table ( near the surface ).

Then came the pressure to build loadsa houses in these margin places.

The developers aid "We have the technology." "We can manage the water table : we can attenuate the flooding."

And thus SUDS Sustainable Urban Drainage Systems gave rise to the possibility of all sorts of underground structures.
e.g. some of these can be like cavernous underground lakes.

My late mother's last house had a mystery manhole in the garden. This contained a dark pit of water, of unknown depth.
That ( modern ) estate was build on a water meadow.
No sign of flooding, even in the worst of the heaviest rainfall.

TurboukToo2
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Re: Manhole Chamber Query

#211279

Postby TurboukToo2 » March 29th, 2019, 1:37 pm

To close this one off - Just had the inspection done and it’s a double width soakaway 2.7metres deep and 3 metres wide. Bit odd as it’s only serving two rainwater downpipes. Not shared and as it doesn’t extend under the area I am laying concrete all is good. Looking forward to receiving the CCTV footage which I found fascinating.

scotia
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Re: Manhole Chamber Query

#211684

Postby scotia » March 31st, 2019, 3:25 pm

I'm glad the problem has been solved, so I hope I'm allowed to be a bit flippant. When working with a communications company which was installing fibre optics cables around the country, we were advised not to use the sexist description "Manhole". They were to be called underground chambers - or UGCs.
:)


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