Strategic felling on the River Feshie helping to fight flooding

A natural solution is being used to combat issues caused by frequent flooding and help protect rare species and designated habitats at the confluence of two Strathspey rivers.

The River Feshie is a highly dynamic river with its origins in the upper Cairngorms.

Part of it is a braided river with extensive gravel beds and home to rare species such as the Northern silver stiletto-fly (Spiriverpa lunulata), that and its history of movement makes this active river an important designated habitat.

Unfortunately, the large amounts of gravel that the river can transport regularly causes flooding issues.

“Where the River Feshie meets the River Spey, the gravel is deposited and forms an alluvial fan that creates a plug effect. This underwater dam can raise the river levels and flood land both upstream and downstream,” explains our Environment Advisor Colin Leslie who oversaw the project. 

For many years we’ve been working our Cairngorms Connect partners, Cairngorms National Park Authority, and NatureScot to try and find a natural solution to reduce this problem.

The previous management involved building hundreds of metres of flood defences (some built by Napoleonic prisoners of war) and dredging the river channel.

Neither of these activities are suitable in such important habitats.

Around 30 years ago, we started removing a small area of trees to allow the river to overtop the flood defences and spill onto our land, while this was partially successful it was not really at a large enough scale to make a significant difference.

So, last summer we expanded this area by felling a further 40 ha of mature conifers. 

We hope the newly created open space, together with the regeneration of native species will help slow the Feshie when in full flow to let suspended gravel deposit safely and water disperse more widely.   

“The area will now be left to regenerate with native species and the combination of riparian woodland, and the open area should create a nature-based solution to a long-term problem” added Colin.

To achieve this was potentially a tricky operation, working in a flood plain with large machinery, near highly designated habitats but our delivery, environment and planning teams worked together to ensure the work was completed to a very high standard preventing large amounts of woody debris being washed into the riparian areas.

Colin added that the work also revealed the source of a local legend.   

“A large mound – fabled to be the burial site of a Viking ship – was uncovered in the middle of the felled area. Despite archaeological investigations having shown it to be a natural feature there are some still to be convinced and they're keeping a close eye on it” 

The development and effectiveness of the site will be monitored as part of the Cairngorms Connect project over the coming years.