Deep in the heart of Glen Sligachan on the Isle of Skye, work is about to begin repairing the path over Druim Hain to Loch Coruisk. This remote site, about an 8km walk from Sligachan, may not be the busiest or best known path in the UK, but the combination of foot pressure and, especially in this case, surface water has created a bare gully 7 metres wide and nearly a metre deep. In heavy rain, water cascades down the path line and, with no vegetation or roots to hold the soil together, more and more of the ground is…