© 2016 Lichfield & Hatherton Canals Restoration Trust
To be continued…
2015 - More clay, a slipway and a concrete base
As 2015 began our work party’s attention was focused on Summerhill - more on that elsewhere. Even so, work started on a canal concrete base and that continued through the year.
In the old days Navvies used to lay clay along the canal bed to prevent water loss. In those days labour was cheap and plentiful and large areas could be done at a time. Today however with only our small volunteer force to do this task we have to do it differently. When clay is laid it has to be kept wet. If it dries out it will crack and will not be any use for retaining water. Therefore we now must work on smaller areas at a time and have water available nearby with which to keep any newly laid clay wet.
We must now work along pound 27 in small sections. Once the concreting has been completed, the 'Big Pipe' can be taken out for say 40 to 50 meters. Concreting under where this pipe was then needs to be done. There is to be a clay infill between the concrete base and the base of the towpath wall. This infill measures approximately 1.5 meters wide and 0.5 of a meter thick. A clay platform is required so that if the canal water level falls any boats tied alongside the wall will just sink down onto that platform.
So, once all the concreting is done and the clay platform laid, and the bank opposite the towpath made waterproof we have to make a temporary dam from side to side. We can now flood the first section. Job done! The next section can now be prepared. Another length of the 'Big Pipe' can be taken out, say another 30 to 40 meters. Any flood waters will need to be channeled back into the big pipe again until these preparations are complete. The black pipe alongside the towpath wall has in the mean time been keeping the minimum permitted flow of water from pound 26 to the weir We then build the next dam a further 30 to 40 meters towards the weir and remove the first dam. So we now have two sections in water. And this sequence is repeated until we reach the weir down by the A38 corner.
Hugh and Terry and a fresh slab of concrete January18th 2015
The Team at Tamworth Road April 26th 2015
The slipway takes shape May 3rd 2015
Ready for concrete May 24th 2015
Photo Christine Howles
Concreting completed May 27th 2015
Photos: Christine Howles
June - The slipway wall
Most of our activities were centred around the slipway, where our normal wall construction methods, although a little slow, result in a very strong structure. In this case we build up a back wall of concrete blocks and a front wall of blue bricks, a course of headers and 3 courses of stretchers, filling the sandwich with reinforced concrete. By Mid-June the wing walls are almost up to the level at which we can lay the bull-nose top courses, after which it only remains to do the last bit of backfilling and tidy up the surrounding area.
The slipway was completed, the last brick laid, the last concrete poured, at the end of July.
More concrete slabs have been laid alongside the big pipe ready for its removal in, we hope, the not-too-distant future. Another important job has been the installation of a by-pass pipe from Lock 26 to the weir corner; this will provide the required dry-weather flow when we start to remove the big pipe.
By March the team were back in force at Tamworth Road. The dry conditions allowed us to move a lot more clay down to the winding hole but we still have problems actually spreading, levelling and compacting the stuff.
Work started on a slipway just below Lock 26. This will be essential if we are to hold the planned IWA Trail Boat Festival in 2018 (subsequently this ambition was put on hold but the slipway will still be a useful feature).
By mid-May great progress had been made in the slipway area, with brick-and blockwork already well advanced, more concrete laid and more ground prepared. In addition a lot of effort has gone into grass-cutting and strimming; the whole area looks very smart.
The slipway is shuttered and the reinforcement in place ready for a load of ready-mix, after which it only remains to build up the wing walls and another important part of the jigsaw will be in place.
August - the base advances
The concrete base is progressing at a relentless pace, although a slow relentless pace. About 4 metres a week in fact. We are now nearing the access ramp half way down towards the weir. Then we will have to continue working on the far side of this access ramp leaving a short section to be concreted after the big pipe is removed.
Soon we will be wanting to place, and work, clay alongside the towpath wall to form the seal between the concrete and the wall and form the platform for boats to rest on should there be a fall in the canal's water depth. A quantity of Hessian sand bags have been sourced, these need filling (2/3rds) and will be used to construct the temporary cross canal dam when we flood the first section.
This latest area now gives us an insight into to the task of lining, waterproofing and protecting this off side bank. We need to achieve a bank with a 2:1 batter (slope to the uninitiated) that is waterproof and will withstand the battering that the narrowboat brigade will undoubtedly give it We need to decide on this so that when the 'big pipe' is removed we know what we are doing and can proceed with the re-watering without delay.
Terry Brown, Site Manager for three years or so up to July 2015, a period of considerable achievement.
Hugh Millington then took over.
October - the pipe is still an obstruction
More progress was made on the concreting of the canal base in pound 27. Dried up clay that had been spread out on this concrete base and rolled to break the lumps had re-hydrated nicely with the rain. In fact almost too much so. I can see that this clay thing is going to tax ones patience in getting it just right. Too little water making it still crumbly and render it useless as a water barrier, too much water in its consistency will cause it to be unable to hold its shape.
Terry Brown made a good start on breaking the concrete around the 'big pipe' just below lock 27, but the concrete in places was at least 2 feet thick and it was hard going. The concrete cap on the inspection chamber half way down the 'big pipe' towards the weir was dislodged an awaits the attentions of the concrete breakers to break it down into smaller manageable pieces.
Over the weekend there was more progress on the concreting front. Terry deserves a mention in dispatches for the progress he made on breaking the concrete around the 'big pipe' on Sunday with a much larger breaker. He and Taxi George wrestled with this hefty machine and all but managed to complete the task before they ran out of time.
Other work on the site saw progress on the levelling of the bank on the left hand side to correspond to the height of the towpath. This will enable us to dress this bank to the required 2:1 batter when we have a digger capable of the task.
November - records are broken
November 25th saw a record-breaking turnout of volunteers. Our own regular workforce, this week there were seventeen of us, was supplemented by five able bodied men from Walton Homes.
Every one appeared good and early and by 10 am the concrete mixer was already in full swing. During the day a record length of concrete was laid, about 12 meters, this brought the concrete base to within another good days work to the weir,. The area around the weir itself is very wet and I fear that we will either have to wait till we have another dry spell or lay a hardcore base before we can concrete the last bit.
Also we moved clay from the storage area to the far side of the 'big pipe' for re-hydrating, where the Waker roller was put into good use to break down the hard lumps within the clay.
Photos: Christine Howles
December - Wet but business as usual
Another good length of canal base was prepared and the concrete laid. Concrete was also poured in the corner where the towpath swings round towards the A51. This left a rather short section of the canal base still awaiting concrete. With all the flood water the black pipe had clogged up and needed attention.
Bob W and crew completed the last bit of concrete down the towpath side. (One can almost hear the Champagne corks popping). But , sorry chaps , there's a lot more to do yet, and it will be hard work with that 'big pipe' still there impeding our progress.
The following week the ground was still pretty water-logged which made the going hard. Deliveries of more clay, more sand/ gravel mix and cement bags came on time. In the morning we were able to strike the previous concrete pour's shuttering and reassemble it just in front of the pipes leading into the weir. Ideally I would have liked to have assembled this shuttering immediately to the left of the big pipe but the soggy ground made this impossible. The concrete mixing gang swung into action after lunch and so another block was soon laid.
Watch the Wacker in action - short video by Paul Marshall
Watch the concrete base advance - short video by Paul Marshall from photos by Christine Howles
By the end of 2015 the concrete had reached the corner
Photo: Christine Howles