Sir, – Myths and fallacies don't become true just because they are repeated carelessly by prominent people, such as Professor Matthews and Roseanna Cunningham.

It should be obvious that to mitigate flooding downstream due to an extreme rainfall event, water has to be stored upstream in any affected catchment. Beavers might be able to help with this if they kept their ponds at a low level most of the time – but they don't.

Beaver build and maintain their dams to keep their lodge entrance below the water surface and the living chambers within above that level. This means they are constantly working to keep their ponds at that level and no higher (or lower).

Even then, the surface area of all the land affected by beaver activity is small in comparison with that of the whole catchment. They would have to tolerate level changes measured in metres, not centimetres to have any effect downstream.

Worse than that, even beaver dams can be breached if the water flow is large enough, so some of the water normally held back by the dam gets added to the flood and actually worsens the threat of damage.

Sandy Henderson

Faulds Farm,