Shropshire Union Canal Society – May 2024 work party report

May 3-6

Success! We finally managed to access the wharf wall area and, in good weather, made substantial progress elsewhere.

The May work party was extended to four days to include bank holiday Monday. Although Monday was mainly given over to cleaning, tidying and various preparations for next time, this did allow for three very full days of activities on site with high numbers attending. Work continued with lining and blocking – a further 30 metres was completed. For the entire 90 metres length that is now lined and blocked, riprap (medium-sized aggregate) was placed over the liner on the towpath bank. This will be covered with soil at a later date. Work continued to profile the channel in readiness for lining and blocking at future work parties. The area south of the compound is now almost complete.

In the same area on the offside bank, a start was made to install the retaining wall to create the ‘soft bank’. This is achieved with two courses of specialised, interlocking hollow concrete blocks. No mortar is used, and the blocks must be carefully positioned and level for the interlocking to produce a robust result. A very satisfying 43 metres of the first course was carefully laid. The first course needs to be filled with earth within the blocks and immediately behind before the second course can be laid but the picture below gives an idea of how the interlocking works. When complete, both courses will be below water level and the area behind filled with earth fully covering the liners. This creates a deep, soil bank encouraging a diverse range of water margin plants whilst still minimising the risk of bank erosion.

Due to the exceptionally wet winter this year, it has been a struggle to drain the northern section of the site by the former tramway wharf. Last month’s attempt, using six different pumps, proved unsuccessful so before this work party, a large 165 cubic metre per hour industrial pump was installed to clear the channel and allow access. This worked! Our existing submersible pumps are now keeping up with the continuing inflow of ground water.

With access now possible, albeit it extremely muddy in the centre of the channel, it was possible to restart work on the wharf wall. The wall itself has now been repaired so the next task is to place coping stones back on the top. These are large and heavy and lifted by machine. Where possible, we are reusing the existing copings although a number are no longer serviceable and new, hand tooled replacements have been sourced. This time, existing, somewhat irregular, copings were used including around a tricky corner. This takes considerable time, effort, and skill to ensure they are stable and level but after 3 days 14.3 metres had been completed. Thanks, as ever to members of the Dry-Stone Walling Association for their assistance with this.