Peat Hags

A peat hag is a type of erosion that can occur at the sides of gullies or seemingly in isolation.

They often arise as a result of water flow eroding downwards into the peat or where a fire or overgrazing has exposed the peat surface to dry out and blow or wash away. Once a hag has formed, the bare peat face can be further eroding by the wind, sheltering livestock, continuing water flow along a channel, water dripping from the overhanging vegetation, or a combination of these factors. These erosive forces undercut the vegetation further and large pieces of overhanging peat and vegetation can fall off be eroded into the watercourses.

Hags are too steep and too unstable for vegetation to establish so the the following reprofiling technique is necessary for restoration.

How is a peat hag restored?

Where the sides are steep or undercut with overhanging vegetation, the hags should be reprofiled to a more stable slope to enable revegetation.

Vegetation on the top of the hag should be “rolled” back or undermined with the root structure intact to enable the underlying peat to be removed to create a 33-45o sloping bank from the top of the hag to the base. The vegetation should then be rolled back and compacted to cover the newly profiled slope.

Where the vegetation does not completely cover the newly re-profiled slope and natural re-vegetation is deemed unlikely, further treatment will be needed using the brashing technique described on the ‘Bare Peat’ page of this website. [link]

For more details of the reprofiling technique, see’Technical Specification 5 – Gully & Hag Reprofiling’.