Report - Dragons Tooth, Manchester - March 2012.

[Ojay]

Dragons Tooth, Manchester

My day of draining continued, and after a couple of fails and much driving/walking about I headed back to a place I had once recced for a closer look

Last time I was here it was dark and quite sketch so I figured it would be best attempted during the daylight

The first thing that hits you here is the smell, like most CSO's there is usually some vapoury fresh lingering about, but this was another stinker!

Sorry to disappoint, but no dragons in here, just some brown trout and enough lady towels to soak up the entire sewer should they end up back in



Covered by a 3m grille draped in fanny plasters which appeared to be grinning at me,
there didn't appear to be an easy way in

Luckily a manhole above had been pikeyed,
so I quickly dropped in and headed up the 4ft square concrete overflow

Further in, an impressive staircase which stretched into the distance

(It was very long & st00py and the picture doesn't really show the scale here)

Once up, a small chamber shrinking to a 3ft RCP, which elevated and curved off to the right

It was quite slippery, and getting up was jokes,
once up I had to squeeze past this jam rag infested catch chain

Ahead was the overflow weir,
it was filthy and full of crap so I scrambled up into the CSO chamber where it was much cleaner

As I shone my torch in to watch the turds, there was a loud noise followed by a sudden surge

Within a few minutes the level had risen a good 2ft which wasn't good considering there had been no rain..

No time to change the underpants I sat it out and continued to watch the flow, eventually it subsided, then within 5 minutes the process repeated itself.. Phew!

There must be some kind of detention tank/syphon upstream which fills and releases ?


CSO Chamber, from Left to Right

GTFO Manhole

Stairway to fresh AIR

I spent more time in drains than United Utilities by the time the day was done..

11 hours of solo draining, I'm f00ked, soaked, covered in crap, anti-vandal paint, cut to shreds by brambles and full of thorns, I've destroyed a pair of wellies in the proceedings.... Showertime and cold beer!​

 

[pastybarm]

That outfall is the spitting image of one in Bolton, now of course I am not claiming that they are one and the same, not at all, but I did find a drain many, many years back with a very similar outfall structure, I will add the pics, and please forgive their now poor quality, they were taken with a VGA camera, at the time, back in't day.

I think this could be controls for the CSO or telemetry for overflows or something?


Old view from the top:

And me stood on top of the grate:

It definitely had a strong smell of gas as I remember, all those years back, but not so much detritus on the grate, as in the pic.

Cheers and happy new years beers,
pb

 

[The Kwan]

Them stairs look amazing, hope the beer eased your pain ....top photos

 

[Dan1701]

You might like to have a look over here: http://www.hydrok.co.uk/wms.html

What is going on in that sewer is that the gradient is too shallow for the flow of water to keep the sewer clear of debris, so some sort of automatic flushing system has been installed. That web page is one of the first ones I found when looking for info on this. The problem has been known about since Victorian times, indeed it was a bigger problem then than now because the water supplies to houses in Victorian times were much poorer, hence there was more solid material and less water going into the sewers back then.

 

[f10w]

Hello from a new member with a morbid interest in sewerage (and other utilities). I live in Bolton and the town's drainage system interests me.

Dragon's Tooth had a (from memory) 6000m3 storm tank installed a few years ago, with a vacuum-operated flushing system to clear settled matter from the base of the tank to the pumping sump as the tank is pumped empty after a storm event. I'm confident that this storm tank was built after this thread was started.

The reason for the rise in level in the sewer every five minutes (in the original post) is because sewage is pumped from further up the system - a pumping station at Harwood Vale rings a bell, but my source for this nugget (old WAPUG reports as well as other internet sources) isn't specific enough to pinpoint its location accurately. There are quite a few pumps on the Bolton system, but the need for one above Dragons Tooth surprises me due to the topography of the town.

 

[Ojay]

@f10w @Dan1701

Here is the actual 'dragons tooth' CSO

http://www.28dayslater.co.uk/scavenger-cso-march-2012.t69545

I purposely swapped the names on the 2 systems at the time, the one you refer to has indeed been upgraded with an off line tank and a vac flush system, there is plenty of info available on the works.

Good to hear from people with a genuine knowledge and interest in local drainage

 

[f10w]

@Ojay

Thanks for the welcome and the references to Scavenger, I had been searching for Dragons Tooth on here to no avail .

 

[Ojay]

'The other one' isn't really documented, it's a bit of an embarrassment as far as UID's go, no doubt it will be fixed in round 7 or 8

 

[pastybarm]

Hello all, and happy new year fellow north westerners!

Thank you for clearing up any confusion Ojay, it is all clear to me now. An apt name for that particular outfall, I must say, "t'other one" is not really well documented as you rightly state. It must be a CSO though, for sure? Given the dubiousness of the surrounding vicinity, I would say it fits in perfectly, LOL! And I actually grew up not much further up the road

 

[Ojay]

Yes it's a CSO you can see from the pics me stood in the trunk attempting to grab a few shots, it wasn't pleasant at all, it seems anything associated with that entire region is Grim.. literally!

 

[pastybarm]

I think I remember seeing the manhole lids for the CSO in question, I am assuming that it serves the surrounding area or allows overflow into the brook to prevent overloading the system? The smell was grim as I remember it years ago, I would agree that below ground in that CSO is a good comparison for what is topside!

 

[UrbanCaving]

Cracking report mate, and your photos are your usual awesome standards

 

[Ojay]

Cracking report mate, and your photos are your usual awesome standards

It's 5 year old this

 

[UrbanCaving]

It's 5 year old this

See I pay attention to the dates me... not lol comment still applies though lol

 

[Snake Oil]

Bolton sewers.......