The port city of Bristol in southwest England has many claims to fame. It was once home to Edward Teach – the pirate better known as ‘Blackbeard’ – while more recent products of Bristol include Banksy, as well as Dave Prowse: the bodybuilder who, alongside the voice of James Earl Jones, played one half of Darth Vader. Bristol also celebrates its history as the first UK city outside of London to call for the abolition of slavery (less celebrated today meanwhile, is its former pioneering role in the pro-slavery movement).

Historical accolades aside, Bristol is also beloved amongst the UK urban exploration community on account of its colossal storm relief drains; most notably, the “Malago Stormwater Intercept”… aka “The Dreadnought.”

The Malago Storm Water Intercept

I first heard about the Dreadnought Drain many years ago. I’d heard of it before I ever ventured into a drain myself, in fact, and the formidable name conveyed both a sense of danger and of awe. Since then I’ve explored storm drain networks in Australia, China and Russia; I’ve seen Victorian sewers beneath London, and the Soviet-era overflow systems under the streets of Kiev. It was only natural then, that sooner or later I would return to explore the Bristol Dreadnought.

The Malago Stormwater Intercept was constructed to manage the overflow of the River Malago, which rises from a spring on Dundry Hill near the Bristol-Somerset border. Both the Malago and its smaller tributary, the Pigeonhouse Spring, flow for five miles through the south of Bristol towards the city centre, where they eventually join the River Avon.

Flowing over an easily saturated terrain of limestone and Jurassic clay, the Malago is prone to bursting its banks during heavy rain; this in turn has historically caused regular flooding to areas of southern Bristol, and particularly in the area known as the Bedminster Basin. Partly in answer to this problem, the 19th century heralded the construction of brick drains and culverts which redirected the Malago beneath the streets of Bristol.

As early as 1880 though, the city engineer Dr. Joseph Yabbicomb had warned that it wasn’t enough. He foresaw the limits of the Victorian overflow and sewerage system beneath Bedminster, calling for further expansion and development of the tunnels – but his warning went largely ignored.

Bristol developed rapidly during the 20th century, including the construction of numerous new housing projects in the south along the course of the Malago. Just as Yabbicomb had predicted, the resultant increase in run-off, drainage and sewerage from these new residential districts was soon pushing the infrastructure to its limits.

In July 1968, Bristol was hit by the worst storm in over half a century. More than five inches of rain fell in the space of just 24 hours, causing a flash flood which swept along the Malago and quickly overwhelmed the drainage systems laid down by the Victorians all those many years before. The run-off from Dundry Hill devastated homes, shops and factories, in addition to claiming almost a dozen lives – as parts of the city became submerged beneath as much as ten feet of water.

In the days that followed, and as the city slowly recovered from the devastation of the Bedminster floods, plans were laid for the construction of a massive storm relief system; one capable of carrying the strain of even a freak, once-in-a-century storm like this.

The new Malago Stormwater Intercept was built from 1971-74, a vast concrete channel designed to collect overflow from both the Pigeonhouse Stream and the River Malago before redirecting it through subterranean tunnels running for two miles beneath the centre of Bedminster… and then safely out into the River Avon. It ran parallel to the Southern Foul Water Intercept – itself a solution to the 40 million gallons of untreated sewage which had, up until the 1960s, been flushed daily into the river. The system would later be nicknamed the “Dreadnought,” on account of the colossal scale of these tunnels.

Before venturing underground to meet the Dreadnought for myself, I decided first to try walking the course of the Malago and getting a feel for the route.

The drain collects from the Pigeonhouse Stream at an intercept just south of Crox Bottom, before meeting the Malago itself in the Manor Woods Valley Nature Reserve. In both places the natural streams collect into ‘shock ponds,’ small lakes designed to absorb the impact of flash floods; before the overflow is skimmed off and redirected through large, steel-barred interceptors and down into the drains below.

After Manor Woods Valley the Pigeonhouse joins the Malago, and the original course of the river weaves alongside the main road, ducking into culverts here and there, or flowing openly beside stretches of the cycle-path known as the Malago Greenway. One final culvert beneath Coronation Road allows the Malago to pour harmlessly out into the ‘New Cut’: a 19th century diversion to the River Avon which allowed for the construction of Bristol’s floating harbour.

A little way downstream meanwhile, the Dreadnought feeds out into the New Cut by way of a vast concrete outfall. Here the Malago outfall tide flap protects the drain in turn, closing at high tide to defend against tidal surges coming in from the estuary [1].

Along the walk, I tried lifting various drain lids here and there; peering into manhole covers in the hope of finding an easy – yet discreet – way to access the network of huge tunnels down below. While the main inflows and outflows were secured with thick steel bars, it wasn’t long until I’d found an unlocked hatch; beneath which a cobwebbed ladder disappeared down into the darkness of the Dreadnought. At that point I pulled back, retreated, fetched reinforcements and waited for a dry day at low tide, before finally setting out to explore the inner workings of the Malago Stormwater Intercept [2].

A Dreadnought Under Bedminster

Bedminster has a peculiar reputation. Now undergoing the slow and inevitable process of gentrification (as the hipsters begin to move in en masse), this historically low-income area boasts more than its fair share of quirky character; but it also has more drugs, more drunken violence, and, some claim, more inbreeding, than perhaps the rest of Bristol’s suburbs put together.

Just a quick flick through some of the recent news headlines associated with Bedminster (“Body Lay Under Sofa for 10 Years in Shared Bristol Flat”; “Cannabis Factory in Bedminster”; “Cat Blamed for Stealing Female Neighbour’s Underwear”) hints at a place of rare and curious charm. It hardly came as a surprise then, when in February 2014 Bedminster once again made the headlines – after a local bus driver reportedly sighted a six-foot crocodile in the New Cut of the River Avon.

The story was covered both locally and in the national tabloids – with the Daily Mail naming it “The Beast of Bedminster.” Bristol Zoo apparently reported no missing crocodiles, while consulting reptile experts suggested that although the claim was unlikely, it was nevertheless not impossible for a crocodile (or more likely, an alligator) to have escaped from captivity somewhere and to have made its home in Bedminster. That initial bus driver’s report was later developed, as other inhabitants began to come forward with what they claimed was photographic evidence of the creature.

By the time I visited Bristol back in February 2014, just three weeks after the first reported sighting of the rogue reptile, crocodile-mania had reached fever pitch. It was with some trepidation then, that I stopped by on an old friend and persuaded him to join me on a mission down into the sewers of Bedminster.

We found the hatch, hidden in bushes out of sight from the main road, and prised it open to reveal the musty darkness beneath. The mildewed air inside carried the mixed aroma of wet leaves and the distant, spoiled-meat tang of raw sewage. We put on gloves and headed in, pulling the drain lid shut above our heads.

That first ladder brought us down onto a metal-barred gantry, an observation platform overlooking the drain itself. From here we climbed further, a long and slippery steel-runged ladder which took us down into a foot-or-so of rushing water. Here at the downstream end of the drain, the flow was at its strongest – strong enough to make for slow progress, as we began to wade through the wide concrete cylinder in the direction of the river’s source.

Not far past our point of entry, the passage split in two – and we stepped out of the stream to explore the dryer fork. This tunnel led up and away from the watercourse, and as I pushed through an archway hung with heavy plastic flaps I was met by an overwhelming stench: we’d found the sewers.

In this side passage, the tail end of the foul water intercept flowed along an open trough before reaching a sinkhole, where it disappeared down to lower levels in a gurgling whirlpool of liquid excrement. As curious as I was about the physics of the system (where this dirty stream came from, where it was going, and so on), the smell was overpowering, and the chamber was filled with the cloying miasma of airborne sewage. I didn’t linger long, before retreating back through the plastic flaps and into the relative freshness of the storm water channels.

We made it back to the fork, this time turning due south – to follow the rushing water to its source. The tunnel veered off ahead in a straight line, a concrete tube marked by occasional ladders climbing back up to the surface. In the distance we made out a dim pinpoint of light, which we guessed to be the infall.

Wading through the stream, we pushed our way through the oncoming torrents of the Malago. Slowly, the light drew closer… but as we approached it that light seemed to flicker, to move, even, swinging about from side to side. What we had assumed to be a fixed point of natural light was beginning to look more and more like a torch beam.

Time slowed as we marched on through the dark passage, and the light ahead became gradually more pronounced. There were voices, too; I’d first heard the soft, echoing murmurs a while back, and had assumed it was the effect of voices on the surface, echoing down through open drains. As we grew closer though, we came to the inevitable conclusion that we were not alone – there was definitely someone else down here, just a little way ahead of us in the darkness.

By now we were no more than fifty feet away, and I turned off my torch. We heard the voices again, just ahead, and the other light cut out too. My mind was racing through all the various possibilities – smugglers, bandits, terrorists – but none of them seemed to make much sense. The rushing waters and damp atmosphere would make this drain a terrible place to hide stolen or imported contraband, while the slim chances of meeting anyone worth mugging rendered it an exceptionally poor location to try staging an ambush. I could only conclude that this other party up ahead were here for the same reason as us: innocent curiosity.

I switched my torch back on, the light ahead reappeared, and we pushed on through the rushing water, closing the distance between us.

As we approached I saw that the light was coming not from the main passage of the drain, but rather from an alcove set into a side wall. We got to perhaps twenty feet away from the source before the muffled voices spoke some fast and agitated command, and the light retreated – moving upwards, quickly, and disappearing through the ceiling. Slowly we moved closer to the alcove, until we stood directly beneath the shaft where the torch had been.

“Who’s that there?” a voice called down to us, in a thick Bristolian accent. Above us the ladder passed through a long concrete cylinder before eventually reaching the surface. At the top, we saw daylight – and three heads peering down over the rim of an open manhole cover. Halfway up the shaft, a platform extended from the wall and on it squatted a figure dressed in overalls and a neon-yellow waistcoat: the uniform of the Bristol & Wessex Water Board. The man was visibly scared, clinging onto the ledge as he tried to make us out in the inky darkness.

“Hello,” we said.

“What’re yow up to then, boys?” asked one of the heads at the top of the shaft.

We told them we were exploring the drains, taking a few photos, and trying to follow the water to its source. Obviously these activities were completely illegal, but there didn’t seem much point in hiding our intentions at this stage – we’d already been spotted after all, while the physics of the situation we found ourselves in would have made it very difficult for these men to enforce the law on us.

Instead, we got a surprisingly sympathetic response.

“Nice one, lads,” said one of the workers. “Good tunnels these. Stay safe down there, mind.”

The man with the flashlight had recovered a little, and sat at the edge of the shelf above us catching his breath after a fast and panicked climb.

“Us’d thought you’m be a crocodoile,” he explained, as he peered down cat-like from his high perch.

Poopsicles and Slurry-go-Rounds

The Dreadnought tunnel, for the most part, is long and straight and smooth. After our encounter with the maintenance workers we walked perhaps another thirty minutes in a straight line. The base of the drain curved down into the centre of the passage, where the stream water flowed around a foot deep; at the sides though, the concrete basin raised to meet the walls and we were able to make faster progress walking on this slippery pavement.

Here at the water’s edge lay a crust of twigs and leaves and muck deposited by the stream. Amidst the refuse we’d find other things – bottle tops and cigarette packs, scraps of paper, hairbands, and occasionally, broken children’s toys.

At one point, a sound like an exploding engine erupted somewhere in the tunnels behind us, turning into a deep, guttural roar which bounced and echoed along the drain. After a momentary panic, we quickly realised what it was – our friends from the water company, doing their best effort at a crocodile impression [3]. It reminded me why I like Bristol quite so much… had this been London, chances are the workers would have reported us to the police force’s terrorist response unit. But here they were instead, playing pranks on us in the drain.

A little further down the tunnel, we climbed a ladder that fed up and into one of the overflow passages connecting to the foul water system. The ladder rose to around fifteen feet, after which we climbed through an arch in the brickwork and onto a steel gantry suspended above the sewer. Long sections of the Malago Stormwater Intercept run parallel to the sewer; although the foul water streams lay deeper in the earth, disappearing from openings like this one into closed passages full of rushing brown liquids.

The chamber was a reasonable size, divided halfway up by the gantry we now stood on. Above us, heavy pipes fed down from the surface to spill their murky contents into the sewer. Most likely we were right beneath a housing estate, watching surface-level sewerage meet the main foul water intercept for south Bristol. The air was heavy with miasma, so I pulled my collar over my mouth to avoid breathing it in directly. The walls around us were slick with grimy residue, a slime which had dripped down from the ceiling over the years to form low-hanging stalactites of semi-hardened slurry. I poked one with the tip of my camera tripod – it fell heavily to the ground with a loud yet strangely satisfying splat, and left a nasty brown streak across the gantry.

Below us meanwhile, just visible through the metal grating, the foul water disappeared down a well and into the deep recesses of the sewer. It was revolting and yet strangely hypnotic; even as I began retching from the stink, it was impossible to look away. I wondered what it would be like to explore those filthy passages – but even with a full body suit and gas mask, the deep and rapid flow of sewage would be almost impossible to navigate safely. For a lingering moment I imagined buying a rubber boat and sailing down the river of sludge – brown-water rafting – before reminding myself that this would be perhaps the worst possible place to die.

We left the sewer before we could breathe too much more of the foul air, climbed back down into the Dreadnought, and headed on upstream towards the Malago infall.

Of Pigeonhouse and Malago

Time always seems to go so much slower underground. That’s one of my favourite things about exploring drains – in many ways it feels like stepping into another dimension. You lose sense of time, but also of place; these self-contained networks exist alongside the street plan up above, but aside from a handful of contact points they spread out to form new, unique geographies.

There’s also a refreshing sense of lawlessness. The feeling of having escaped the confines of the city up above, with its rules, its hierarchies, its surveillance systems and its appointed guardians, to venture instead into a parallel realm where all are equal; where titles and property become irrelevant in the face of exploration and camaraderie. Our encounter with the workers from the water board had reinforced that feeling. Up above they had uniforms, jobs and responsibilities – but spying us down here in the bowels of the city, they had known that such things made no difference. It was clear that these men understood the rules of the underground.

We must have been in those tunnels for several hours at least, before we again spied light up ahead of us; and this time it was a soft, natural luminance, the gentle translucent glow of daylight at the end of the drain.

We heard the interceptor almost as soon as we could see its light – a roar of falling water, made all the louder as it echoed down the passage towards us. On the edge of Manor Woods Valley Nature Reserve, the River Malago pours through a cage into a concrete-bottomed pool from where the overflow is skimmed off, falling down a series of steps into the Dreadnought. Joggers and dog walkers out in the park would never have imagined how grand a thing this infall was, to behold it from within. The oversized staircase, the mouldy brickwork arches, had an air of ancient ruin about them; of classical architecture lost beneath a sea of moss and churning water.

We climbed the steps from the drain floor, up slippery, flooded slabs to find ourselves inside the cage of the interceptor itself: sunlight, at last, and the fresh waters of the River Malago. There was no exit to be found from the cage however, the bars sealed closed to keep out trespassers. Besides which, we still had a further length of drain to explore – the final section of our route, leading beneath Crox Bottom to the Pigeonhouse interceptor a little way upstream.

By now I was becoming acutely aware of the time, as well; we had entered the drain just a little before the low tide, but now that tide was on its way back in.

It took perhaps another ten, another fifteen minutes from there. In this section of the drain a wide pavement had been built beside the water; parts of it had already cracked away from the wall however, to leave a precarious ledge jutting out above the stream. I soon grew tired of hopping over the cracks, and chose instead to wade deep in the murky torrents. Early on, we’d tried our best to avoid getting wet and dirty; we’d long since passed the point of no return though, soaked to the skin and plastered head to toe in unspeakable filth.

Eventually we made it – coming out of the tunnel into a chamber much similar to the one before, but this time with no through-passage. It was a dead end, the Dreadnought’s brick-walled terminus, where the Pigeonhouse Stream poured into the drain from the steel-barred interceptor above. Someone had written “The Sex Pistols” across a green-tinted wall beside the infall, in graffiti so faded that it could easily have been there since before real punk went out of fashion.

Two miles might have never seemed so far… but after all that, we were still only halfway through our journey: trapped underground breathing fresh air stolen through metal bars.

We didn’t emerge from the Dreadnought until late that afternoon, finally heaving up the manhole cover from beneath to roll out onto the grass, smeared in moss and silt and sewage, coughing, shivering and laughing. By the end of it all, we hadn’t found the crocodile – the elusive Beast of Bedminster – but it certainly hadn’t been for lack of trying.

[1] I’d like to thank Steve “Not The Wrestler” Austin over at the Malago in Bedminster blog, for some excellent background information on the original watercourse. His detailed work in mapping the overground landmarks of the River Malago gave me a much clearer understanding of the interplay between Bedminster’s rivers and drains.

[2] Having already described the function of the Malago outfall tide flap, it could be argued that I didn’t need to wait until low tide to explore the drain – I just didn’t want to take any chances, though. Even though the Dreadnought outfall closes at high tide to prevent backflow from the Avon, presumably the water level inside rises as a result of being trapped.

[3] I’m going to state the obvious here, before someone else does: crocodiles don’t roar. Neither do they wear headlamps, or have the ability to squeeze between the narrow bars of the Malago outfall tide flap.