Report - Holloway, Holloway Extension, High Level and Ratcliff Storm Reliefs (aka Heavy Mettle), London 2018

[tallginge]

Heavy Mettle

Like most drainorz over the years I first set foot in the Holloway Storm Relief on a quest for Orly. It’s one of the most impressive junctions in the London Drainage System and didn’t disappoint. I did a report on it and the rest of Deep Ochre last year. At the time I found it hard to leave what looked like a clean 7ft brick pipe going off in both directions, east to west, but knew I’d get back to it eventually. I ended up doing most of this at least twice in the end and as usual some bits were on my own, some bits were with @TheVicar and some with @Ojay.​

History-wise there’s not much to go on but I found a useful table online with some construction dates. The whole article is in the link below but the following is from the appendices at the back​

High Level Interceptor completed and in full operation 1861
High Level and Ratcliff Relief 1881 to 1884
Holloway Storm Relief 1884 to 1887
Mare Street and Morning Lane Relief 1890
Holloway Storm Relief Extension 1893 to 1894
High Level to Mid Level No.2 Relief (aka High Level Relief) 1909 to 1911
North-East Storm Relief 1921 to 1925​

http://www.sewerhistory.org/articles/whregion/1930_abm1/article.pdf​

I’ve described it from the upstream end near Holloway to the downstream end at the Thames near Limehouse Basin as its simpler to understand. As usual I/we walked it over numerous visits.​

We’ll begin with what was my most recent visit on my own. I’d walked a large portion of this end with TheVicar last year but didn’t get many pics (which is probably why I then lost them). I’d also previously visited two adjacent overflows from the High Level but hadn’t got pics of that either so the plan was to go back, get pictures this time and see if I could get any further.​

This is the last pic I took before I got to some spiral stairs 100m or so further North West. The whole storm relief is very silted up along most of its length and the going is usually tough and slow. At this point, though, it’s also stoopy, it being only about 5ft high but at least 6 inches of that is soft, silty, festering shite (which makes it less than ¾ of a TG high – my limit ) I’d had enough by this point but the pipe continued. It must end at something, though, it being so deep still – likely just another shaft. The ladders at the end of the pipe (on the right) go 50ft up to a breather in the middle of the road. About 10ft below this breather on the opposite side of the shaft from the ladder (annoyingly) was an overflow from another large drain I could see into. Whether this is a local sewer or the Hackney Brook remains to be seen.​

I’d walked up from the pipe on the right and had a look up the shaft behind the railing before going to see what was up another 6ft pipe behind me.

There’s a brick dropshaft – something I wasn’t expecting to see, again, after all the concrete. It’s seen better days, though. I think the High Level Interceptor can overflow into it here but can’t be sure. There’s a large shaft nearby with nothing else in it but ladders and a split lid at the top. Disappointingly, I failed to get a reliable GPS from beneath the lid.​

This is where TheVicar and I turned back last time. Hardly surprising as we’d walked several miles by this point, stooping a lot through soft silt, having failed to find a useable exit west of Orly. We didn’t expect to find one further along either and the ladders in the next pic had a steady flow of shit raining on to them. This time they didn’t, though, so I went for a wander around the overflow at the top of them​

Turning around from where the ladders pic was shot is the High Level Interceptor (looking upstream) Note the shite left over from the last overflow event, through which the piss (and the rest of it) flows down the shaft and onto the ladders​

From the other end of the chamber you can see it wouldn’t take a lot of extra flow for it to be over the boards​

Just upstream and around the corner is a smaller overflow known as Parasite. Spill flows enter the Camden Road Relief which heads south west to join the Fleet. I grabbed a couple of rubbish pics of it and climbed up the step irons back in to the chamber. As I was doing so, I heard something fall out of my pocket onto the floor followed seconds later by a plop. By the time I realised I'd left my pocket unzipped and realised it was my lenser, it had disappeared into the plunge pool below. It’s still there now if anyone wants to go magnet fishing? Just behind where this pic was taken, quite a lot of flow joins the interceptor – I wondered if this is was where the Hackney Brook joined or if it was just another local sewer?​

Back to the mainline of the Holloway and there’s a bend. There’s not many of these so I stopped for a photo​

Further downstream is a side pipe entering from the left. This doubles back to run parallel to the Holloway for 30m or so, doubling in size before arriving at this huge shaft with a flap at the bottom. TheVicar and I didn’t bother with it last time as we’d too much to do still and on my own I couldn’t open the flap up enough to get through. I could get me camera through, though, so grabbed a pic. It’s just concrete and seems to go on forever. I suspect it meets up with another overflow from the High Level​

Back to the main line and there’s this chamber, not far from the Arsenal stadium. I went to see what was happening up top. The pipe enters the shaft horizontally and joins the vertical part by a plastic T junction. Through the top of the junction you can hear and smell the sewer behind but it was too high to reach over and take a pic (without dropping my camera 40ft down the pipe, anyway)​

Then there’s this old connection or one that was built but never used.​

Next up is the Orly junction. I didn’t even know Orly was a fuckin internet owl until recently, whatever one of them is. Oh really? The North East Storm Relief, which flows south from here, was one of the last storm reliefs to be built (1921-25). Essentially it intercepted the Holloway and takes all of its flow (and that of the two mid - level sewers) directly down to the Thames.​

In the pic below, storm flows go down the pipe on the right while another overflow from the High Level cuts across into another pipe just behind the horizontal bar. The tunnel continuing on straight ahead is the downstream Holloway. It’s unused for a short distance and therefore silty for a while.​

This pic might explain that a bit clearer. The flap in the pipe on the right used to be attached to the vertical iron beam in the pic above.​

This is the overflow from the High Level, ¾ of a mile from the Holloway, that enters Orly from the north. It used to be the last one before the Holloway rejoined the interceptor a mile or so further down. It was an obvious place to start the North East Storm Relief from.​

A short distance after Orly and we (me and Ojay this time) arrived at a split. But why, why is there a split? Well I don’t know. Usually where pipes split it’s because something big is in the way and can’t be moved but the flow still needs to get by. But for its 400m length it crosses no tube lines and no canals and besides, it’s still about 20m deep. The New River (an artificial waterway opened in 1613 to supply London with water) used to cross at the eastern end of the split but was culverted. Surely it wouldn’t have been that deep 400 years ago? Maybe the ground was so poor (because of the New River?) that the ground wouldn’t support a 7ft pipe but would support 2 x 4ft pipes laid side by side?​

Before Orly was built there would’ve been quite an amount of flow coming down here. The concrete balancer pipe looks like it’s been added in as an after-thought. We had no intention of seeing if there was anything else to see inside the split – not in a month of sundays!​

This end of the split marked the end of a different visit with TheVicar this time. We’d walked up from the start of the Holloway Extension. The silt, along this section, was particularly deep making the going slow and tough (for a change)​

This is an overflow from the London Bridge Sewer, I’m led to believe. Not been up it – maybe one day. Also, TheVicar in his T-shirt.....​

This is the end of a short storm relief from a trio of sewers that Ojay and I visited one rainy weekend.​

This is another overflow or branch off from the London Bridge Sewer. About 10ft along it another decent size pipe drops in from 10ft up. No way up to it from below, unfortunately.​

The Holloway Storm Relief used to rejoin the Northern High Level Interceptor here until the line was truncated 20m before it arrived. The Holloway was extended from here in 1894 and now flow goes down to the pipe on the right into the extension, which runs parallel to and deeper than the nearby Interceptor. Unlike the rest of the Holloway which is mostly more than 15m deep and tunnelled, the drains here are relatively shallow and likely dug cut and cover. I should think digging so close beneath the Northern High-level for several hundred meters gave some cause for concern for all involved.​

I’d been to this section four times in fairly quick succession and always wondered how the Holloway eventually met the High Level but couldn’t see properly for the damn dam boards in the way. With a bit of climbing up the lowest two I managed to lift off the upper two, somehow and took this pic. Whilst TheVicar said a prayer I climbed back and somehow struggled (a lot more) to put them back in their place so we could begin our days draining. On a nerdy note, the Interceptor is about 50ft above the Storm Relief only 2 miles away as the crow flies. The interceptor doesn’t follow the same, straight course as the storm relief and is perhaps twice as long (so 4 miles). I checked and “it’s fall is rapid, ranging at the upper end from 1 in 71 to 1 in 376 and from 4 to 5 feet per mile (1 in 1000) at the lower end.” Yeah I’d say 50ft over 4 miles is rapid for an interceptor that size – and that’s only if the Holloway is completely flat for two miles (which it probably nearly is). Presumably the penstock reduced flows to a sensible amount so the Holloway could be connected to the interceptor.​

Looking back from the extension​

 

[tallginge]

This is where things got confusing for me, the first time I had a mooch around here. My last report from this end I now consider as something of a joke, it’s so full of errors. Here’s a link to it if you wanna laugh.​

https://www.28dayslater.co.uk/threa...ratcliff-storm-relief-london-aug-2018.114299/​

Basically, the map at my disposal (at the time) misled me in much the same way (I think) as it has misled others in the past. TheVicar kindly directed me to a certain post he’d found (amongst hundreds) on UER (which isn’t searchable) and all became clear. When we explored it all properly, lots of things slowly fell into place. I’ve produced a little sketch which kinda shows how the collection of sewers, storm reliefs and connecting pipes interact.​

This is the bottom of the reverse ramp – likely constructed between 1909 and 1911 (15 years after the extension) when the rest of the High Level to Mid Level No.2 Relief (aka High Level Relief) was built. The extension used to continue full bore before the dam boards and ramp were built which now restricts flows to a 6 inch diameter hole at the bottom. Sustained storm flows are now diverted up the ramp but it’d likely back up all the way to the truncation before it breached the top of the ramp. The whole 100m of extension here acts as a stilling pond and goes some way to explaining why the bottom of the ramp area was ‘anging when I went there with Ojay. We’ll come back to this blockage later…….from the other side…….​

This is from the top of the ramp, looking back towards the flap. Behind the flap is a short 4ft connection pipe, which carries overflows from the High Level Interceptor.​

The High Level and 4ft connection pipe​

The 7ft Pill shaped overflow heads south. It used to only go as far as the Mid Level No.2 but some time between 1933 and 1955 it was extended on to Deep Ochre. TheVicar and I went to see how far we’d get. My wadorz were leaking but it’d be fine right? It’s a storm relief……​

We could hear water falling for 10 minutes at least before we arrived at a large tumbling bay. We knew the storm relief used to join the Mid Level No.2 near here so where was the interceptor? Well, the tumbling bay takes the whole lot under the interceptor and it just carries on at a lower level. No nice connection or overflow weir to a new pipe then? The tumbling bay’s cool and all that but I was a bit disappointed. I wonder, though, what’s behind the small penstock? Perhaps the original connection exists after all.​

On a different (more recent) visit I went to see if anything else happened on the way to Deep Ochre, not expecting much. I was right to be pessimistic. Nothing at all happens, apart from a small overflow that joins from the west. Up it there’s a small chamber but I suspect it was just a local sewer that passes through, it’s only 4ft but it could’ve been the Ratliff Highway. I didn’t even get my camera out on that occasion.​

To the sound of music playing from some guy in the park above we made our way back north to see how much of the High Level and Ratcliff we could get done. We popped out further up in the park and surprised plenty as it was a sunny weekend.​

After a short walk above ground we descended into the Ratcliff at a decidedly busy lid - the best of a bad bunch. We walked northwards (upstream), passing bits and pieces until we arrived at the other side of them dam boards. At this point it’s still part of the Holloway extension. This photo was probably taken directly beneath the Interceptor, somewhere close to where their paths cross.​

We then retraced our steps for a while until we got to a feature we’d not expected – well I hadn’t. It’s another rather nice (and original) overflow from the High Level Interceptor.​

The bottom of the shaft marks the beginning of the High Level and Ratcliff Storm Relief and the end of the Holloway Extension as you can see by the different bricks used. Construction of the Ratcliff was completed in 1887 and the extension started in 1893 so for 6 years there would have been a shaft from the chamber above with just an outgoing pipe (and no incoming RBP as well). To enter this shaft the extension has to cross under the interceptor somewhere (see pics^^^^). That would’ve been some engineering feat, back then, digging underneath a 9ft 3in RBP almost lengthways, constructing a 5ft RBP as you went.​

A short way down there’s more engineering bricks around a new connection. This is the outfall of the Mare Street and Morning Lane Relief constructed in 1890. I don’t know for certain what it connects to at the other end but its probably worth seeing – at some point.​

This is one of the most calcified staircases I’ve ever seen but the sewer wasn’t much different.​

An air shaft – the features were few and far between now……​

…..until after what felt like ages the pipe changed to 7ft egg, then RBP, which flattened as it turned sharply right and entered two wrought iron conduits barely 3ft high. It exits in a similar fashion but turned sharply left. The two parallel iron conduits carry what minimal flow there is under what I believe to be the Hammersmith & City and District tube lines – this part constructed in 1902. If my research (and theory) is correct the sewer was built first so the railway presumably could not be constructed to avoid clashing with the sewer. So, the sewer had to be altered to fit around the railway, hence the 100m section of 7ft egg upstream of the conduits. Either way you can’t stoop 3ft, the best you can hope for is to squat right down and try and walk like that or it’s hands and knees time. It’s no wonder Hackney used to flood. It may look smooth and curvy but it feels very confined and the twists are very tight. Unless I’m mistaken (and I might be) this tunnel took all overflows from the High Level Interceptor for 7 years until the High Level Relief (the pill) was built in 1909.​

From the other side, now, looking upstream. The pipe on the left goes to Deep Ochre. I went to check once. After 5 or so minutes going uphill in a 4ft 6in (at most!) empty pipe, I started to go downhill and this rat had joined me. The poor thing wouldn’t let me past for another 10 or 15 minutes. It was fucked by the end of it, as was I. Difference was, I didn’t leap off the 5ft staircase at the end and land belly first in Deep Ochre. It didn’t do that again…. The journey back to the Ratcliff was long and lonely. And still only about 4½ft high.​

We passed a lid that @siologen once helped me with (thankyou very much!) and around a few twists and turns until it started to get deeper. The Thames was now only half a mile or so away and nothing of much interest really presented itself until we got to the Low Level No.1. The huge flap to it had been raised since my previous solo visit and dam boards now diverted all the flow underneath. Naturally, we went for a look…not down the ladder to hell, though.​

This part of the sewer is also shown as a diagram on Ojays report. The diagram confusingly refers to the Ratcliff as the Holloway Storm Relief Sewer, which it isn’t any more, really, but the idea is that a new penstock and flap valve chamber will be built to divert flow down here permanently, avoiding the need to connect it with the Tideway Scheme.​

The old outfall flaps have been replaced with these modern looking duckbill valves, at least that’s what I think they are. You can hear the Thames lapping away behind them​

We exited nearby absolutely exhausted, gladly not to an audience this time. TheVicar kindly got us a taxi back to my van. We’d got a bag with us and shoes, thankfully. My shins were soaked and my socks went straight in the bin! I think we’d walked about 5 miles underground that day.​

Thanks for good times down there Ojay and TheVicar – top company, patience, lighting skillz and lid lookin for us, both of yers ​

Thanks for lookin’​

 

[Yorrick]

Christ! So much awesome! Stunning work man

 

[Ojay]

Yes great report and was a hard slog for much of it, the pics always make these places look cleaner and easier than they are in reality

The brick shaft that terminates that 'newer' concrete relief North of Holloway is a bit of a mystery as well, it runs up Tollington Way towards Shroud Green which is nowhere near the High Level Sewer

From my original recce's years ago with that lot never found anything sizable nearby either; the brickwork also doesn't look mega old either... Again more questions eh

Just a couple of bits of the Ratcliff for me to still see

Top notch as ever, that pic of @TheVicar behind them boards still makes me chuckle to this day

 

[TheVicar]

Another cracking report TG.
Reading this brightened up my morning, if felt like we were back underground slogging through the muck!
You were lucky to have no overflow down that shaft with the ladder where we turned around on our visit early last year, it's good to see what you found up there.
Doesn't seem that long ago when we did the High Level SR and the whole of the Ratcliff that day but it was a few months now and the weather was still warm.
That diagram you have done of the HSRE with the HL Interceptor and Storm Relief is top quality. There's a lot going on just there and you can barely see half of it at once in person so the diagram is very helpful.

I lolled when I read your comment "I didn’t even know Orly was a fuckin internet owl until recently, whatever one of them is. Oh really?"

 

[tallginge]

Christ! So much awesome! Stunning work man

Thanks mate, glad yer enjoyed it

Yes great report and was a hard slog for much of it, the pics always make these places look cleaner and easier than they are in reality

The brick shaft that terminates that 'newer' concrete relief North of Holloway is a bit of a mystery as well, it runs up Tollington Way towards Shroud Green which is nowhere near the High Level Sewer

From my original recce's years ago with that lot never found anything sizable nearby either; the brickwork also doesn't look mega old either... Again more questions eh

Just a couple of bits of the Ratcliff for me to still see

Top notch as ever, that pic of @TheVicar behind them boards still makes me chuckle to this day

Yeah that was a tough one, the Ratcliffs easier though and yeah I'd like to revisit it from the three way split down. Didn't realise the Tubes newer (if it actually is) - I wanna walk back up that egg section and a short way up the stoopy third pipe (on the left). They'll be crackin' on with the new works by the low level as well. Regarding the upper section I've PM'd you with where I think it went and no the brickwork doesn't look that old - and only single skin on the base! Only one way to find out for sure what goes where.......Whatever's at the top of them ladders, across the shaft that I saw through the overflow didn't look small but I couldn't see it properly

Another cracking report TG.
Reading this brightened up my morning, if felt like we were back underground slogging through the muck!
You were lucky to have no overflow down that shaft with the ladder where we turned around on our visit early last year, it's good to see what you found up there.
Doesn't seem that long ago when we did the High Level SR and the whole of the Ratcliff that day but it was a few months now and the weather was still warm.
That diagram you have done of the HSRE with the HL Interceptor and Storm Relief is top quality. There's a lot going on just there and you can barely see half of it at once in person so the diagram is very helpful.

Haha pleased to have brightened up your morning. Yeah that ladders was slimy as fook but I got some elbow length gloves for xmas - they came in handy here. I'd forgotten my waterproof coat so was especially grateful for a lack of leakage from the interceptor. I went a lot later than when we did, which may have made all the difference. No it doesn't seem that long ago, does it but yeah long days and sunshine - been missing that for sure. Won't forget that blokes face on the bench - grumpy old scrote. Glad yer liked me 'lil sketch' of the junction - I couldn't remember if I'd shown it yer before. I wonder if the two interacted at all here before the reverse ramp and Pill were built to relieve them both - probably not.

 

[pastybarm]

Are the sections that are concreted for reinforcements for crossrail development above, or just because the old brickwork was no longer up to par? Looks look like a lot of twists and turns down there, but then I suppose it is a given the capital would have bigger sewers than other cities, or am I wide off the mark?

 

[tallginge]

The concrete doesn't have anything to with crossrail, no. Crossrail does er cross, though, somewhere near the double twist cast iron conduit section but i don't remember seeing evidence of it doing so from inside. Yeah many twists and turns and yes again, london has the biggest sewers or the most big sewers of any city in the uk, it being the capital.

 

[Speed]

More maps please.. I like it but I can't follow the descriptions half the time. Bloody drains are too complicated!

 

[tallginge]

@Speed It's a tricky one so have PM'd you. Google london sewer map or type abbey mills or northern outfall sewer into flickr for a clearer version. Yeah drains are complicated enough with maps, nigh on impossible to understand without one - fair point

 

[Speed]

That little map of the junction you have in this thread suddenly makes it obvious what's going on but trying to understand some of the other bits from the description is a bit of a mind bender. Guess i will have to go and work it all out in person..

 

[tallginge]

If I had a map as clear as what I produced for all of london i'd be a happy man. Maybe I should've included what I do have at the start of the thread.

 

[Ojay]

That little map of the junction you have in this thread suddenly makes it obvious what's going on but trying to understand some of the other bits from the description is a bit of a mind bender. Guess i will have to go and work it all out in person..

Yeah that’s the thing we do our best to explain but really you need to see this sort of stuff in the flesh to understand/appreciate it all

 

[tarkovsky]

Awesome, these photos are great and I had to read the words all the way through at least three times before I felt qualified to comment. Unfortunately now I’ve got nothing intelligent to comment, damnit. So many features in these London drains it puts Sheff to shame! That diagram is spot on too!

which makes it less than ¾ of a TG high

Good to see you using the official drain measurement terminology.

I’ve even been beaten to it with the Orly meme, so I’ll leave it with the ascii version instead.

,___,
{O,o}
|)``)
O RLY?

Keep ‘em coming.

 

[tarkovsky]

I actually can't get my head round that last picture though? What am I looking at?