But in contrast to England, Sepa, which seems to stand for the “Scottish Everything Prohibited Agency”, is intransigent in its refusal to let landowners clear such a build-up, even when there is a clear risk of a future Alyth-style event.
The River Druie at Coylumbridge is a case in point. Unprecedented river levels last winter caused widespread erosion of the banks and dumped huge mounds of the debris in the river course downstream.
After the event, the estate at Coylumbridge urgently needed to stabilise the bank next to the holiday lodges, where more than ten metres of banking had been lost.
Instead of working with the estate to resolve the problem in a reasonable manner, however, Sepa simply adopted a “gonnae nae dae that” mentality and made it as difficult as possible for the repair work to be undertaken while also prohibiting any attempt to clear the piles of uprooted trees and other debris from the river course.
The end result is unsightly and a loss of amenity, but the real concern is that this is a ticking time-bomb waiting for another big water to unleash a totally avoidable “Alyth event” on Inverduie and Aviemore.
Those communities might well ask why an apparently unaccountable quango can impose such a risk by diktat without so much as a word of explanation or consultation.
I was interested to read Eddie Palmer’s letter regarding blocked water courses. Although I welcome his implied defence of the beavers, I would also point out that fallen trees, and other woody debris, can have large benefits for river life.
They provide habitats for fish, reptiles, amphibians and aquatic mammals, as well as providing shelter for some species to lay their eggs.
Fallen trees also slow the flow of sediment and water, thus slowing floodwater. Only if and when they become a hazard, or a potential flood risk, should they be removed.
The sheer ferocity of flash floods can, of course, negate their mitigating effects.
As I said in my previous letter, the beavers were victims of a flash flood precipitated by a particularly heavy downpour in a short period of time, and they were not alone.
A tiny otter cub was found in a car park in Aberfeldy, presumably separated from its mother after being washed out of its holt by the floods.
Judging by past flooding events, there will have been many other unrecorded casualties.
We should prepare for further incidents of summer flooding.
Recent research carried out by the Met Office and Newcastle University, and published in the peer-review journal Nature Climate Change, found that our summers would become drier, but would be marked by more extreme downpours. Drier land means less absorption of rainwater.
Vulnerable areas are expected to experience a big increase in these incidents in future.
Summer downpours are harder to predict than winter rainfall, and their sudden onset, particularly after long dry periods, can have devastating effects on both wildlife and humans, as we have seen.
Let’s set the record straight with some facts about the flooding in Alyth (your report, 23 July).
The problem of flooding on the larger scale has to do with bare, unforested uplands.
Work done by the British Geological Survey has shown that soil under old deciduous woodland has 10-to-15 times the permeability of soils under neighbouring coniferous forest and pasture land.
Precipitation runs off open grass and moorland, and coniferous woodland, very fast.
The Alyth Burn catchment has the problem that a wide upper catchment feeds into the funnel of the Den and then into the canalised Burn that runs through Alyth. This was an accident waiting to happen.
The force of the flood was actually uprooting trees and sweeping them down from high up in the catchment.
(Dr) Elspeth Stirling