Middlewich breach caused by lock paddles left open

The canal breach wasn’t caused by an embankment collapse but by a ‘tsunami’ of up to 3 million gallons of water sweeping down from the lock above – where all four paddles had been left open.

Early reports said that a 70-metre section of an embankment on the Middlewich Branch of the Shropshire Union Canal between Wardle Lock and Stanthorne Lock had ‘collapsed’ overnight on Thursday 15th March. A mile of the canal between the locks had been dewatered, marooning about 20 boats on the short 1 mile pound, leaving one Springer narrowboat and its sleeping occupant perilously close to an enormous hole where 2,800 cubic metres of the embankment (equivalent to over 200 lorry loads) had been washed away into the River Wheelock below.

Most reports said the embankment had collapsed, drawing parallels to the embankment breach at nearby Dutton which closed the Trent and Mersey canal for 7 months in 2012. Various social media commentators blamed collapse on the sandy nature of the embankment at that point, damage done by badgers from a local sett, lack of dedicated canal lengthsmen or planned maintenance failings by CRT. The MailOnline got appropriately hysterical reporting a 100 foot wide sinkhole appearing at 11.40pm. ‘A sailor was nearly sucked down … while he was boating…. the sailing boat just feet away from being sucked down sinkhole.’

It now appears that the breach was more likely to have been caused by extra water flooding into the pound running across a low section of the towpath, ‘overtopping’, which started to wash away the towpath and then increasingly rapidly gouging out the side of the embankment. The reason for the excess water is that four paddles had been left raised at at Stanthorne Lock and four at Wardle Lock. This would have had the effect of running large volumes of water down from the 5 mile pound above, eventually dropping the level of the upper pound by about 8 inches, probably over 3 million gallons!

However this excess water should not have been able to flood and then overtop the canal bank to such an extent. Most lengths of canals are equipped with weirs to run off surplus water, but because this pound is short it appears that there were none here. More importantly, if the paddles were also raised at Wardle lock, why did water levels build up at all? Water should run through both locks and flooding would be more likely in the next pound down. But it appears that when the raised Wardle paddles were noticed they were dropped – without realising that the Stanthorne paddles were also up. The flooding water instead found the lowest section of the bank, a low section on the embankment of which CRT was reportedly already aware.

So overtopping is the likely cause of the breach. But who left 2 sets of top and bottom paddles open? There was a report of a boat speeding up the length that night, possibly carelessly leaving paddles raised. But of course a boat could never get out of the top of a lock if the bottom paddles were raised, the lock simply would not fill. Vandalism is a more likely possibility; drained pounds at Middlewich are nothing new and perhaps the intention was to cause flooding in the town? Top and bottom paddles are also raised by CRT staff to move water to sections short of water. Could this have been done overnight to avoid disrupting boat traffic and left too long, and the problem compounded by someone then dropping the Wardle paddles and the low towpath? That seems highly unlikely, the most likely conclusion must be that the breach was the work of vandals.

The IWA reports that ‘by Wednesday 21st March, CRT had installed a temporary dam on the Middlewich side of the breach site, to enable water to be pumped from the Trent & Mersey Canal into the Middlewich Branch over the following few days, to refloat the 20 or so boats in the affected section and to give them access, via Wardle Lock, to the waterway system again. The boat that was between the breach site and Stanthorne Lock remains marooned.’

A CRT 20th April update states that ‘The design to repair the breach is progressing well. The topographic survey information shows that 2,800m3 of the embankment has been washed away … and it will need to be replaced. Our engineers are assessing the condition of the arch of the aqueduct, currently there has been no structural damage to the arch, however due to the loss of ground, a careful assessment is needed to confirm whether construction vehicles can safely cross it. ‘

‘We’re hoping to confirm realistic budgets and timescales by the end of May but, at the moment, our best estimate is that repairs will take six months from June at a cost of between £2m and £3m.’

This means that the stretch is unlikely to be open until 2019. The Middlewich Branch or ‘New Cut’ is very popular with boaters, forming an essential part of one of the network’s most popular cruising routes, the Four Counties Ring. It also links northern canals to popular western cruising areas like the Llangollen Canal and the Shropshire Union Canal. Alternative routes add about 6 days to the journey. The affected canals contain marinas with thousands of private boats, and there are numerous holiday hire companies whose fleets use the closed canal. Many hire firms were already having difficult times, local Middlewich Narrowboats went into receivership over the winter, and loss of their most popular holiday routes will hit hire firms hard, some already reporting cancellations. Most are hoping hirers will explore the other routes they offer.

As they did for the Dutton breach in 2012, raising £22k towards the £2.4 million cost of repairs, CRT has launched an appeal for donations towards the cost of the repairs.

Thanks to Roger Evans for use of the photos.