Knowing I’d be in Cardiff for a couple of days with a slim amount of spare time I’d been looking for possible explores within reach of the city centre. Although I’d not seen a report of this, the disappearing blue line on the map looked promising. I then remembered watching a documentary on ‘Hidden Cardiff’ that featured this culvert, so decided it was worth a look. Entry was a bit of a pain in the arse as the first time I was free there were far too many people about. However, an early alarm the following day allowed me to make my way in without being noticed.
The culvert runs for about half a mile under the centre of Cardiff, eventually emerging again before flowing into the Bute East Dock.
The Dock Feeder Canal runs along the eastern boundary of Bute Park from Blackweir at the north end, south to the Castle, where it turns east, and runs along the north side of the Castle to leave the park. It then passes under North Road and along the south edge of Cathays Park, until it is culverted upon reaching Park Place, and it finally emerges at the southern end of Churchill Way.
It was created in the 1830s, in connection with the construction of the West Bute Dock. The function of the Feeder Canal was to provide a constant supply of fresh water to the dock to keep the entrance channel clear. "This heavy and expensive piece of work was rendered necessary by the fact that the tidal water of the Bristol Channel is unsuited for use in a dock, owing to the large quantity of mud it holds in suspension, and the heavy deposit resulting from it when in a state of quietude."
The Feeder Canal terminated at a reservoir. "This reservoir can be discharged at low water, by means of powerful sluices, with cast-iron pipes, five feet in diameter, and by ten sluices at the sea gates, so as to deliver at the rate of 100,000 tons of water per hour."
(More info here: http://www.cardiffparks.org.uk/bute/info/dockfeedercanal.shtml)
At the entrance to the culvert, there’s a large stone and brick tunnel with a small gap before entry into a choice of two square concrete sections. I soon realised that this was going to be a lot deeper than I had expected as my first few steps ended up with me breaching my wellies and slowly walking through water that was, at times, up to my chest. Having not had space to pack my waders, however, it was either a case of putting up with getting wet, or not doing it at all....
Looking back to the entrance.
In the concrete section, I chose the left tunnel. This was a little less deep but still breached my wellies...
This then led into an interesting semi-open section, within walkways to the centre and above the canal. A double grate below stopped the larger detritus from going further....
Then onwards back into the darkness, into an older tunnel.
Having been channelled into a more narrow section the flow was faster here, and the water got really deep again.
Big pipe crossing above...
The brick soon turned into concrete again...
This seemed to go on forever into the distance. I kept waking as the water got deeper and the tunnel itself got shallower and shallower, until I was stooping in what had previously been a really large space. With no end in sight, and quite a way into the culvert in deep water, I decided it was sensible to bail and return the way I came.
This is the outfall, hidden in some bushes behind a hotel. I didn’t have time to check it out properly, so I’m not sure how big it is, or how far off I was when I gave up...
And here’s the Bute East Dock fed by the canal...
PS. The Hidden Cardiff doc is here:
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