In reply to Bob Bennett aka Last Thursday:
In the Lake District erosion, caused by over-grazing, land cultivation, drainage and human trampling, has resulted in soil loss and excessive sedimentation of watercourses, leading to local increases in flood risk and damage to important habitats and several freshwater priority species. The Forestry Commission (FC), Cumbria Woodlands, the National Trust, The Woodland Trust and Natural England, have come together in joint initiatives to address issues such as water quality, soil erosion and flooding across the National Park. As part of this work, Forest Research has created maps for Lake District National Park that identify land with vulnerable soils at risk from hill slope and stream bank erosion, where woodland creation has the potential to reduce diffuse pollution and improve water quality.
http://www.forestry.gov.uk/fr/INFD-7T9JRD