REWIGGLING A RIVER

Restoring rivers to more natural shapes has huge benefits for wildlife - as one project in the Cairngorms demonstrates

- PETER CAIRNS

OVER CENTURIES, WE'VE PROFOUNDLY CHANGED Scotland's rivers - pacifying them and bringing them under our control. We've felled native woodlands to 'tidy' riverbanks, disconnected watercourses from their floodplains, and dredged and straightened river channels. For most people today, these simplified riverscapes are normal, and reflect their expectations of nature. As a society, we are blind to ecological loss and celebrate neat, orderly landscapes, where nature's inherent dynamism is put in a box.

But things are changing. Responding to a free fall in wild salmon numbers, coupled with the growing frequency of major flood events, river scientists and land managers are increasingly embracing natural river processes. ‘Stage zero’ is a concept being applied to rivers and watercourses that have been straightened or otherwise modified. It recognises that rivers don’t naturally follow the linear channels we have allocated to them but, instead, want to weave across a loosely defined river-wetland corridor that features ever-shifting channels, wooded islands, backwaters and ponds. In time, a more dynamic and diverse mosaic of habitats develops, boosting biodiversity and retaining water at times of extreme high and low flows.

My first experience of this approach was at the Rottal Burn in Angus, one of the primary salmon spawning tributaries of the River South Esk, which flows through Glen Clova on its way to the Montrose Basin.

“The Rottal was straightened for drainage in the 1840s,” says Dee Ward, the landowner. Dee was a pioneer in restoring natural processes to a river for the benefit of the now-endangered Atlantic salmon. “Every time the burn flooded, young fish, eggs and gravel were just washed away,” he recalls.