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 prevents it draining into the ground below. On 18/3/23 we manually removed some of the debris to clear the river and show we had started to deal with it.
We had to cross the blacksmith’s shop with digger, tractor and trailer to clear the large 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 temporarily removed the boiling house foundation bracket and cover for this work, it will be put back when 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 damaged walls were fenced off as these areas were unsafe.
On 24/10/23 we had a meeting about the damaged walls. Rebuilding the river wall with bricks would be too expensive, I looked into grant funding but none were available. There were concerns a brick wall might fall down again without major modifications. The options 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; 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 first fell, so another option is leaving it as it is with minimal extra work.
After 3 years we have still not managed to start the works due to Fred's high workload. We were planning a Sloping River Bank but we are now considering Leaving the Wall As It Is but making the top safe by removing the overhanging soil and tar floor, removing the small brick end section to expose the Carrstone wall and minimal brickwork to finish the curve (bricks and lime mortar are already on site).
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 scaffold or timber frame to support the wall, dig a trench the other side to relieve pressure, insert wedges to straighten the wall (Lime mortar is flexible), backfill, use Wall plates & anchors to hold the wall 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. The boiling house foundation bracket cover near the bridge shows a small part of the tar floor which will be left, 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 to be fitted into the river bank. I held this back to build into the new wall, as its the ideal location in a vertical bank by slow flowing water with enough height above and below their nest tunnel.
On 19/1/23 we started measuring the bow in the trench wall by stretching cotton between two points and measuring the distance to the wall, the bow was 185mm. We can no longer do this as the end of the wall is now leaning out at the top, so we have lost a reference point, but it is visually much more bowed out.
The Grey Wagtail box was removed when the wall collapsed in case the end fell down, which it did when clearing debris. The box will be put back when works are complete, either on the wall or another location. There is another Grey Wagtail box at the other end of the site which we believe was used. All nest boxes are from our Green Grant.
Graham Bartlett
Interactive Plan Collapse Activity Green Grant Clear Debris Gallery Volunteer Preservation
