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Montgomery Canal Restoration Review 2016

 

The 2016 restoration season was productive to a degree that could only have been dreamt about some eighteen months ago. A full programme of nine three-day work parties ensured that all of the planned major works were completed and, for the first time, work extended beyond the confines of the first 75 metres of channel from Pryces Bridge. To top it all CRT were successful in their bid to the Heritage Lottery Fund for funding, some of which will be applied to the Pryces to Crickheath section.

March saw the start of construction of the permanent works – the retaining wall-cum-mooring adjacent to Pryces Bridge. The plan was to excavate for the foundations of the mooring and then use the resulting spoil to build up the badly subsided towpath – what could be simpler? We quickly discovered that an 8-tonne excavator could dig at a far greater rate than the power barrows could cart the spoil to the towpath and the site was soon covered with ‘temporary’ storage heaps - an unavoidable consequence of the small working area available. Elsewhere a second group of volunteers assembled four large reinforcement cages for the base of the mooring. This involved wiring up the individual pieces of pre-bent mesh which had been delivered to site in the autumn. This giant three-dimensional jigsaw puzzle took most of the weekend to solve.

‘Water, water, everywhere’ was the mantra for April. The work commenced on All Fool’s Day and the weather gods’ joke was a brief period of dry weather instead of the promised deluge. This allowed the completion of bulk excavation but the adjacent pile of spoil reached new heights. The rains came with a vengeance for the rest of the weekend making the digging out the base, blinding the excavation bottom, and installing the formwork a real test of the volunteer spirit. The rain ran down the sides of the excavation and caused a series of earth slippages which required remedial shoring. Groundwater began to appear in the bottom of the excavation making continuous pumping necessary. On the Sunday morning – still raining - attention turned to the problem of moving the reinforcement cages from the compound to the mooring – about 150 m. They were too big to go on the dumper so the only solution was to carry them! It took twelve volunteers just to lift them and shifting them all the way to the bottom of the channel was, well, pretty hard work. The last test of ‘volunteer spirit’ was to lift the cages into position and adjust them for final level and alignment; not something that many present would have bet on at the start of the work party.

So the base was finished and, bar the installation of expansion joints, ready for the concrete six days later. What could go wrong? Alas....... the next day a narrowboat somehow managed to hit the stop-planks at Redwith Bridge, damaging them and causing the level in the Redwith to Pryces section to rise to full height. This in turn caused increased leakage into the worksite at Pryces Bridge. There was a real fear of inundation but, in the absence of any further heavy rain, the pumps managed to cope with the inflows for the rest of the week. The following Saturday a dozen volunteers, aided and abetted by three large ready-mix trucks and a concrete pump, finally placed the concrete in the base. Relief all round!

The May work party is usually close to the top of any list of the most productive events during the Society’s restoration season and the 2016 edition was no exception. The four-day marathon (it included a Bank Holiday) made use of good weather to make substantial progress on the mooring and to commence work on two other major projects. Work got cracking on the blockwork walls of the mooring with the ambitious target of progressing to a point where concrete could be poured at the start of the next work party. A mighty collective effort achieved this half an hour before knocking-off time on the last day. Work also started on the second ‘big ticket’ items on the current section - the culvert which passes under the canal adjacent to our compound. Since the ‘day job’ of the culvert was to drain a substantial upstream area work in it had to be done in such a way as to preserve its drainage function. This caused a considerable amount of head scratching in planning the work. The first task was exploratory excavation of the old brick culvert to get information to inform the design of its replacement. Volunteers had the task of excavating, by hand, behind the culvert headwall. What they found was a 200 year old brick culvert in poor condition: penetrated by tree roots, prone to collapse and only held up by the surrounding earth. Total replacement with modern materials was necessary – a major task for a bunch of volunteers!

The June and July gatherings were dominated by work on the mooring and the culvert. Construction of the mooring settled into a pattern of two months worth of block laying followed by a concrete pour, whereupon the process was repeated. The attention of the bulk of the workforce was centred on the culvert. The detailed design of the work was done by Society members and when the mass of pipework and fittings was delivered it was great fun trying to work out which bit fitted into which. Installation work quickly got underway. After seemingly endless chiselling, sawing, drilling, grinding and filling, the back of the headwall on the Lloyd’s side was judged to be in a state to take a plastic pipe coupling. This was fixed to the headwall using a variety of bolts, washers and two types of mastic. Meanwhile excavation of the old culvert yielded large quantities of 200 year old bricks, some still in surprisingly good condition. The new 450 mm diameter pipe sections were assembled ‘on dry land’ before being lowered into the trench and bedded in pea gravel. By the end of the June work party the pipework reached its lowest intended point beneath the bed of the channel on the Lloyd’s side. On the other side of the canal the search began for the other headwall. Eventually, with a little help from the 8-tonne digger, the top of the culvert, a headwall and a manhole were uncovered. All were unceremoniously removed and a temporary bridge erected over the big hole in the towpath. No going back now.

We all started in July knowing that the culvert had to be finished in the next three days. As they say – no pressure. A reinforced concrete base was constructed for the replacement towpath side manhole. Work started to extend the pipe beneath the canal bed from the point reached in June. However there was a problem – there always is! Soon after the last work party, heavy rain had flooded the site (together with much of the local area) and a thick layer of silt covered the location of the pipe. Eventually the missing connection was found, cleaned out and the next length of pipe attached. The rest of the day was occupied with two things. The first was shifting an enormous volume of earth from the bed of the canal to permit the safe installation of the remaining pipe sections. The second was keeping our collective fingers crossed for another day of dry weather. Sunday morning and – big sigh of relief - no rain. The blocklaying gang had been transformed overnight into the bricklaying gang and they immediately started work on the new manhole on the towpath side. Meanwhile after a small amount of extra excavation sections of pipe were installed to bring the culvert to a point beneath the towpath. These sections were duly surrounded with pea gravel and backfilled. The final task was the pipe connection under the towpath to the manhole so that it was capable of performing its drainage function. There it was – all 24 metres of it. We had done it!

The August work party literally broke new ground as well as making progress on the mooring and finishing work on the culvert. Patient work by CRT had resulted in the acquisition of land for newt ponds, these being a pre-requisite for a newt licence application for the next phase of the restoration. The site of the new ponds is familiar to the Society since it is the site of our old Redwith base. After being set out with the help of CRT ecologists, excavation of the ponds started and 20 tonnes of puddle clay was delivered. We soon found out that the job of puddle clay lining is not as simple as it seems. Suffice to say we had learned the hard way that bulk clay must be broken up, followed by lots of water and boots to get it watertight. Messy but fun! Back at the mooring the third and final concrete pour completed the filling of the blockwork. The stone walling gang had the damp-proof course on the wall and the first stones laid before the end of the weekend.

After the high jinks of the three previous months the remaining work parties were more sedate affairs. In September three visitors from the Heritage Lottery Fund were shown some of the Society’s work in connection with the CRT bid for funding for the restoration. The stone facing on the mooring was completing. Elsewhere the second newt pond was lined, and the bricks salvaged from the old culvert together with assorted tree trunks transported to Redwith. These were used the next month to construct newt terrestrial habitats. This rather grand sounding activity involved digging a shallow trench, filling it with a mixture of the tree trunks and bricks, and then adding a covering of soil. The remaining major job was the completion of the French drain using the Society’s latest secret weapon. To date gravel has been delivered to the drain trench manually using buckets and a pipe as a gravel chute. A Mark 2 gravel chute was constructed which allowed gravel to be tipped direct from the dumper into the drain excavation. Ten metres of drain was installed in just 2 hours using the new system, a massive improvement on the old method.

The remarkably dry weather during the November event made earthmoving possible even at this late stage in the year. Full advantage was taken of this complete work on both the mooring and the towpath. The mooring was backfilled with concrete and compacted soil, and the building up and surfacing of the Phase 1B towpath to grade was completed. This is certainly a great improvement on the muddy switchback which was there before. The other big news at the November work party was, of course, the award a couple of weeks earlier of the Heritage Lottery Fund grant to CRT, some of which will be used to fund future work on the Pryces to Crickheath section.

The overriding impression left by this year’s efforts is the enthusiasm of, and amount of work completed by, the volunteers. The upshot is that all of the programmed items for this year have been completed. Work continues throughout the winter on clearance work for the next (HLF funded) phase of the works which should give us a flying start for 2017!

 

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Culvert head-wall shenanigans
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French drain construction with the new gravel funnel
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Newt ponds
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Newt terrestrial habitats under construction
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Wharf wall nearing completion
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John appears to be demob happy
November 2016
2015 Review
March 2017

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