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Montgomery Canal Restoration Review 2011

 

The end of the ‘restoration season’ gives us a chance not only to rest our collective weary limbs but also to reflect on the Society’s restoration effort during 2011. As most readers will know the work is concentrated on 430 m of the Montgomery between Redwith Bridge and Pryces Bridge. The work started in March 2008. By the start of 2011 the entire 414 m of stone wash wall on the towpath side was finished, together with 90 m of reinforced concrete retaining wall located on the offside at the Redwith end. Much of the work on Pryces Bridge itself, including the invert, was also complete.

The first three work parties in January, February and March included both hedge-laying and work on the channel. Some 150 m of hedge along the towpath was finished (just!) by the end of March under the watchful eye of Margaret Powell. The work was difficult because some of the hedge was disturbed during the work by contractors to pile and rebuild the bank in this area prior to 2008, with the result that the hedge growth appeared at different levels on the embankment. The result, however, is a very high quality piece of hedge-laying and is a tribute to the 40 volunteers who contributed to the work over the course of the winter.

The other department was less successful in those first three months of the year. Work on shaping the channel literally got stuck in the mud. The problem was not only the rain (not a common occurrence in Shropshire!), but also both the volume of ground water and the resulting level of the water table. A technique had been developed in 2010 of excavating the base of the canal and then installing a land drain which permitted water to be pumped away. Although the idea of putting a drain in the bottom of a canal might sound a bit counter intuitive, it in fact works. The drain enables water to be disposed of quickly and hence permits vehicle movement without excessive damage to the base of the channel. The problem in those early months was that it was so wet that we decided to dig out the base and leave the drain until later. Big mistake..... We arrived in March to find our carefully excavated channel looked like, of all things, a canal! It took us a whole day to pump that lot out and we learnt the lesson.

From April onwards all the workforce returned to construction or channel shaping work. But something else happened in April – our luck with the weather changed. The work party was held in glorious sunny dry weather and this pattern continued more or less for the whole of the restoration season. It had a major influence on progress.

Initially the construction element was finishing the facing of the offside retaining wall with stone and this continued until the topping-out ceremony in July. This brought to an end the stone wall building which commenced on our first day on the site in March 2008. Just about every volunteer contributed to the wall construction in some way over this time. At the start only a couple of volunteers actually laid the stones but by the end some 25 had (aided by training and experience) become competent in this task. The wall builders were backed up by the unsung heroes of the mortar mixing and transport gang who did one of the hardest physical jobs on site. The retaining wall construction involved varied expertise in excavation, reinforced concrete and blockwork as well as stonework, and all were done to a high standard.

The output of the channel shaping gang from April onwards accelerated with every passing dry month. The work consisted initially of excavating the bottom of the channel to just above finished grade and making sure that this was level. The french drain was then constructed. This esoteric sounding device consists of a half metre deep trench which is then lined with a geo-textile. A perforated plastic drain pipe is inserted and the trench refilled with small sized stone known as ‘pea gravel’. A sump, also made of plastic pipe, is constructed at intervals to enable water to be pumped out. The fact was though that very little pumping was necessary and then only to lower the groundwater levels rather than to dispose of rainwater. The other two parts of the digging gang’s task was shaping the sloping banks of the channel, and building about 80 m of bank where none existed. The latter is in the centre of the length adjacent to the culvert. Two slopes had to be formed – one about three metres long on the offside and a smaller version on the towpath side. Each had to be shaped accurately to provide the profile of the finished channel. As with all jobs practice made perfect. The spoil from the excavation was moved by dumper to the site of the new bank, and spread in layers and compacted. Care was taken to make sure that the bank was constructed to more or less its finished slope so as to minimise the amount of subsequent work necessary. It is fair to say that progress on all parts of the earthmoving exceeded all expectations during the year with well over 100 m shaped.

Many of the erstwhile wall-builders were redeployed onto the work on the towpath. A new fence was completed along the whole length. Its design was such that work could be done on the towpath without adjusting the position of the fence. The other effect was to make the towpath into a more walker and cycle friendly corridor judging from the many complimentary comments people from both groups. The surface of the path also received attention. In the first instance it was thoroughly weeded. If anyone has doubts about the dedication of the Society’s volunteer this should dispel it, since the task involved kneeling on the rough stone surface and removing the offending plants by hand! The final task was surfacing with stone dust dressing and rolling the surface. This job was in fact finished about one hour before knocking-off time on the last day in November. The rolled stone dust is a very effective surface as demonstrated by the fact that completed sections are still, at the time of writing, in pristine condition undamaged by foot or cycle traffic.

And finally, the bit we had all been waiting for, the lining of the channel. Two small lengths of channel were lined in 2008 (at Redwith Bridge) and last year (at Pryces Bridge), but these were, respectively, a trial and a demonstration. In October we did the first ‘production run’ of lining. The work party got off to a hectic start with the arrival of 2 trucks carrying 2000 concrete blocks. Also arriving was a mini-bus carrying 17 personnel from RAF Shawbury. Each course run at Shawbury undertakes a community day and we benefited from the combined muscle of No 386 Joint Air Traffic Control Course. The result of this was to smash the record for attendance on a single day with 44 people on site. Just over 15 m of channel at the Pryces Bridge end was lined and it is fair to say that by close of play on Sunday there were some very tired volunteers on site. However this task will, like all the others we have tackled, speed up as our accumulated experience guides us to improved working methods.

So, those are the highlights of a restoration year that has been both successful and great fun. Roll on 2012.

 

David Carter

 

 

I feel I must also give a message of thanks to all the volunteers who have attended 'Our Length of Canal' over the year. Every work party exceeds my expectations, the 'jobs up my sleeve' to prevent anyone standing around getting bored (can’t have that!) are usually completed as well as the planned works.

It might be totally wrong to single out one effort in the year for particular praise, but I have to say the work on the Sunday of the November work party, completing the towpath, was certainly at the next level as far as effort and commitment was concerned. It also got praise for quality from the BW engineer during his inspection! What a team! My thanks to all concerned throughout the year and hope to see you all again in 2012.

 

Mike Friend

 

 

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Mike                                               Penny Welfare case
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Sacrifice to the weather gods The other diners were impressed by our sophistication
November 2011 March 2012
2012 Review

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