Conserving the peat cliff at Malham Tarn

Views across the moorland at Malham in the Yorkshire Dales

In 1791, Lord Ribblesdale raised the water level of Malham Tarn by approximately 1m, to increase the area available for fishing. In doing so, he unwittingly caused serious damage to the area of raised peat bog on the northern shore of the tarn, which we are now trying to address.

Rising water levels

The western edge of the tarn forms the edge of the Malham Tarn National Nature Reserve. When the water level was raised, the vegetation around the shore was flooded.

This area of reeds and fen vegetation acted as a natural barrier, protecting the peat cliff from the wave action of the water. Without the barrier and with the water at a higher level, there is nothing to protect the exposed peat face from both water and wind erosion.

Preventing erosion

The edge itself is now a peat cliff, in some places 3m high. The cliff face is eroding by as much as half a metre per year.

With a Biffaward grant, we are attempting to stop this erosion by creating a new barrier. The barrier will work initially by breaking up the wave action hitting this western edge, reducing the force of the water. Behind this barrier we can then re-introduce marginal vegetation that, once established, will again protect the cliff face.