As part of our repair work on Helm Crag we identified a section, leading up towards the summit, that we'd been keeping a close eye on for many years that had steadily been deteriorating. The path would have been difficult to repair with stone as it's not particularly steep, meaning there would be plenty of opportunity for people to step off the path and walk beside it. There is also very little in the way of features, rough terrain or large rock about so it would have been difficult to landscape. This could have eventually ended up with an erosion scar (as you can see in the photo below) alongside the stone path, not ideal.
So we decided the best option to repair the path would be to create a sub-soil path. This technique, also known as soil inversion, is an ancient technique that dates back as far as Roman times.
Firstly we had to select the best route to take with the new path. The path will zig-zag up the hill crossing the original (eroded) path line. We have to snake the path like this to reduce the gradient which will mean once we've created the new surface the chance of it becoming mobile is greatly reduced. It will also make the path easier to walk on.
With the route decided, the first job was to remove the turfs from the line of the path and place them to one side so that we could use them later.
With this done, the next job was to dig off the topsoil, again this was placed to one side as it would also be needed later. This dark layer, rich in humus (organic matter), varied in depth, but beneath it was a layer of compacted red sub-soil. The idea is to remove this compacted soil, put the topsoil back on the path and then put the sub-soil on top of it. This new surface is much more hard wearing and compacts down well, creating a more sustainable surface.
Next a side drain was created on the top side of the path. This would catch any water that runs down the hill, and shed it away from the new path. Much of the drain went through areas of bedrock, so this all had to be chipped out with crowbars to make sure the drain would sit well below the surface of the path.
Once the drain was dug out, it was lined with turfs using the grass that had been originally dug off. This turf lining will provide a protective layer and prevent the soil in the drain from being washed out.