Our riverside wall collapsed on 2/1/23 and the trench wall is cracked and bowed. We believe the damage is due to the tar floor between the walls preventing water soaking down into the ground, forcing the top of the walls out, causing the trench wall to bow and the river wall to collapse. The tar floor has a layer of soil above that absorbs water, but it prevents water draining into the ground below. On 18/3/23 we manually removed some of the debris to prevent it affecting the river flow and to show we had started to deal with it.
We had to cross the blacksmith’s shop with digger, tractor and trailer to clear all the debris so we covered the blacksmith's area with soil to give access to the fallen wall. We decided to permanently cover the area, as severe deterioration had already taken place. We had to temporarily remove the boiling house foundation bracket and cover for this work, it will be put back when the works are completed.
We had to wait for dry conditions to get machines on site, as the track to the mill becomes slippery in winter. On 10/6/23 the digger was taken to the mill and debris from the fallen wall was removed from the river, most was taken away to be crushed for ballast, some was left at the mill to use for wall repairs. The area between the walls was fenced off with Keep Out signs as the fallen and cracked walls were unsafe and the ground between them was badly churned up by machinery, making it difficult to walk on.
On 24/10/23 we had a meeting about the damaged walls. Rebuilding the river wall with bricks and mortar would be too expensive due to the materials and time involved, I looked into grant funding but no suitable grants were available. There were also concerns a brick wall might fall down again without major modifications and strengthening. Options considered were: A cement bag wall which was also expensive, not environment friendly and they don't look very good; a sloping river bank to match all the surrounding banks with smaller brick corner which was the lowest cost option; and Gabion Baskets filled with rock. Now the wall has been down for over 3 years, nature has taken over with tall vegetation growing in front of it and wildlife nest holes in the exposed soil, which looks much better than when the wall fell, so another option is leaving it but making the top safe by removing the overhanging soil and tar floor.
We originally decided to replace the fallen wall with Gabion Baskets filled with similar colour rock to the original wall. However after 2.5 years we have still not managed to start the works due to Fred's high workload. We then considered a Sloping River Bank which would be much less work and hardly any brickwork, as the curved wall would just be made good instead of fully rebuilt to meet gabion baskets. This would also save a lot of money as no materials would be needed because bricks and cement for the curved wall are already on site. This option would allow natural water drainage. There is a Carrstone wall next to the fallen wall, we will expose as much of this as possible. We are now considering leaving the wall as it is but making the top safe by removing the overhang, removing the small brick end section next to the carrstone wall and minimal brickwork to finish the curve. The fence could be left in place.
The trench wall was perfectly straight when built in 2017 but has been bowed since early 2019. I suggested supporting it with wall anchor plates, but this was not done and it has got much worse. The top of the end of the wall is now leaning out and there is a large crack, it could fall at any time. Repair options are: Build a frame using scaffold or timber to support the wall, dig a trench the other side, insert wedges to straighten the wall (Lime mortar is flexible), backfill, use Wall plates & anchors to hold it in place, then repoint the crack; the other option is to remove and rebuild the bowed section using bricks already on site, but as the bowed section is now so large, this would be an enormous task.
The tar floor between the damaged walls, which we believe caused the wall problems, will be either broken up and removed, or have holes drilled in it for drainage to prevent further damage to the trench wall. The area will then be grassed over again when work is finished. We don't like removing original features but we have no choice when it could cause major damage, the tar is not visible anyway as its under soil and grass. We have other tar floors running up to the boiling house, also grassed over, the boiling house foundation bracket cover shows a small part of the floor, the bracket and cover will be put back after the works are complete.
When work starts this page will be kept up to date. Volunteers will help with repairs and preliminary work, we have already started to make preparations for repairs:-
On 20/2/25 we checked to see if the Carrstone wall is within the fallen wall area by digging into the exposed soil, we couldn't find it but we plan to expose as much of the Carrstone wall as possible on the other side of the fallen wall.
On 2/9/23 we refurbished the boiling house corner bracket surround and cover, as it was removed so we could access the fallen wall to clear up debris. We filed off splinters, sanded it down and painted it ready to put back after works are finished.
In November 2023 we modified a Kingfisher nest tunnel so it can be built into the new river wall. I held this one back hoping to build it into the new wall as its the ideal location, as Kingfishers like vertical banks or walls by slow flowing water with enough height above and below their nest tunnel. If a sloping river bank is created instead of rebuilding the wall we will find another location for the nest tunnel.
The Grey Wagtail box was removed when the middle of the wall collapsed, in case the end also fell down, which it did when clearing debris. The box will be put back up when works are complete, either on the wall or another location. There is still a Grey Wagtail box at the other end of the site which we believe was used. All nest boxes are from our Green Community Grant project.
Graham Bartlett
Interactive Plan Collapse Activity Green Grant Clear Debris Gallery Volunteer Preservation
