Now, as regular readers of this blog will know, I’m not one to be controversial, but I do feel quite strongly about the tone of the latest updates on progress to repair that dirty great hole in the canal near Middlewich.No doubt based on a press release by Canal and River Trust, the Telegraph, Express, Nantwich News and others have reported that the March breach, which will cost around £3m pounds and will take until Christmas to repair, was caused by a boater leaving lock gates and/or paddles open on the upstream Stanthorne Lock.
Now, there’s no suggestion that this was deliberate vandalism, and no mention of damage to the lock itself, so I’m confused as to how water could have “ended up gushing down the canal, washing away the banks and leaving a huge gaping hole in the waterway”. After all, opening both lower gate paddles at once is normal practice when descending a lock…
Even if both top and bottom paddle paddles where opened at the same time, the flow would still be restricted by the size of the lower paddle opening, about 3 square feet in total. In operation it takes around 5 minutes to drain the lock through these openings, dumping around 360,000 gallons of water into the lower pound. But the turbulence caused is resisted by the construction of the wash walls below the lock. By the time the water has flowed down to where the breach occurred it would be a shallow wave, no more. Not at all of the Severn Bore proportions implied by water “gushing down the canal”.
Sorry CRT. I know that a lot of occurrences of structural damage on the canals can be placed at the doors (or bows…) of boaters, especially during the silly season, but I don’t believe this is one of them. Aqueducts over waterways are vulnerable from both the canal above and water erosion below, and as such need to be checked and maintained rigorously. With cut-backs in staff maybe that’s not possible any more…
OK, rant over.
Meg continues to improve, she’s getting about better now, is eating like a horse and is more alert. We’ll have another visit to the vet next week to check her vitals, but we’re cautiously optimistic.
And I’ve finally finished the saloon doors, and I’m quite pleased with the result.
Different, eh...
Locks 0, miles 0
9 comments:
Wow! Did you do the stained glass? I onviously missed some blogs. They are very nice indeed.
Kath (nb Herbie)
Well impressed with your glass work :)
Love your rant Geoff, well said!
Love your doors even more, as you say they are different, but they are beautiful, love the design, the craftsmanship and the colours are lovely too. Very well done!
Great to hear too that Meg is feeling more like her old self.
Love to you both. xx
Windows look outstanding Geoff!
Doors look Mint Geoff, glad to here Meg is better if only for now.
Regards to Mags.
Cheers
Ade
I think the explanation of paddles being left open is very plausible.
Paddles at both ends of the lock were found up by two boaters from the stranded boats investigating why the water was still flowing after the canal was empty, even before CRT arrived. It's not clear if three or four paddles were found up.
CRT's maintenance inspections had identified a slightly low spot on the towpath at the site of the breach some time ago. This was close to the aqueduct, but not at it. It had been listed as a maintenance task for the bank to be raised - at some time - but no urgency or need to use resources on it straight away as it was still six inches above normal water level.
There are many such low spots around the network and the lowest spot in every pound is a weak point and potential source of failure. If you raise them then the next lowest spot becomes the potential source of failure so you can never fix them.
With the pound gradually filling over many hours the water eventually reached the level of the low point on the bank and would have started to trickle over. That trickle gradually washes a little of the bank away and it flows faster and faster as more bank gets washed away and the water level continues to rise. Only lowering the water level quickly would have stopped the breach - but nobody knew of the problem until too late - except for the person(s) who left the paddles up.
A boater passing through the lock may just have through it slow to fill/empty if one paddle was inadvertently left up at the other end. If they are a lazy boater who leaves the paddles (and gates) open on departure, then the breach is almost inevitable. There was nothing special about this site, it will happen anywhere a boater (or vandal) leaves paddles open at both ends of a lock.
The breach was close to the aqueduct but that was merely coincidence and the damage to the aqueduct was caused by the breach and nothing to do with the original cause.
The breach a few years ago at Minworth was caused by vandals opening the paddles on the top lock. The pound between the top and middle locks filled until it over-topped the middle lock gates (which were the lowest point on that pound) and started to fill the pound between the middle and bottom locks. That pound breached when it started to trickle over the lowest point in the pound and the trickle gradually washed away more and more of the bank and became a torrent until it all ended up on the adjacent road.
The recent breach near Wordlsley Junction was caused when heavy rain caused the River Stour to overflow into the canal. The excess water flowed down the bywashes of the bottom locks of the Stourbridge 16, then filled the pound at the bottom until that reached the lowest point when it started to trickle back into the river. The trickle washed away the bank and, as before, it gradually became a torrent and it all ended up in the river.
Hi! long time no see. Do hope we will enjoy a catch-up,
when you are nearer.
I too, am a fan, of stained glass.
Think your efforts, are a huge success.
Love & Best-wishes to you both.xx
In addition to Paul’s explanation of the breach, I understand CRT believe it was vandalism — but don’t want to say so for fear of giving others the idea.
Thanks Adam, interesting observation. I'm not sure I'm happy that CRT are blaming an unknown boater instead of admitting that it may have vandalism. The excuse of not wanting to give others oiks the same idea doesn't wash though. Every year there are several incidents of this type of vandalism, all over the network. Not so much in Cheshire though, so maybe it's a local policy...
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