This winter, Dorset Wildlife Trust has been deliberately installing dead trees in a valley near Ansty, says conservation officer Stephen Oliver
Implementing nature-based solutions to reduce the flood risk from surface water and improving water quality and habitat for wildlife are the two main objectives of river restoration work.
Dorset Wildlife Trust’s rivers conservation officer, Stephen Oliver, describes the work involved in the Devil’s Brook project:
‘This exciting partnership project involved two kilometres of river restoration work completed on Devil’s Brook, a 14-kilometre long watercourse rising in the chalk hills near Higher Ansty and flowing south to join the River Piddle near Athelhampton. Much of the river has, over time, been heavily modified, straightened and over-widened, which has significantly reduced the habitat quality and biodiversity of the river.’
‘A partnership of organisations – including Wessex Water, Wild Trout Trust, Farming and Wildlife Advisory Group Southwest – with the support of Environment Agency and Natural England, has been working with local landowners and managers to look at the opportunities to undertake river restoration work.
Trees, whether standing or fallen, provide vital habitat along a watercourse. Unfortunately, modern land management practices mean that fallen trees are often removed. Our Rivers and Wetlands team, with the help of local land managers, trustees and Wessex Water volunteers, have installed 33 Large Woody Debris (LWD) features along a two-kilometre targeted reach to replicate fallen trees. The LWD consists of locally-sourced trees of different shapes that are positioned in the river and pinned in place using chestnut stakes.
Fallen trees naturally provide much needed shelter and food for an array of wildlife. But this necessary habitat is often lacking due to our tendency to ‘tidy up’ and remove these features, fearing that they are causing a problem.
In fact, nine times out of ten, a fallen tree along a watercourse causes no hazards and should be left in place to encourage natural processes along our modified rivers and streams.‘
Riffles and scours
‘The LWD features that have been installed will dramatically transform the current uniform habitat (same flow, same depth) in this area – they will physically change water flow and direction. This will allow gravel riffles and scour pools of varying depths to form, increasing the diversity of wildlife that can make its home in and around the river.
‘Dorset Wildlife Trust staff and volunteers working on site were treated to excellent views of kingfishers and dragonflies, who were quick to perch and admire these newly-installed habitat features! Now that the project has been completed, we will be carefully monitoring for changes to the habitat and wildlife abundance in order to see what impact the work has had.’
Find out more about Dorset Wild Rivers: dorsetwildlifetrust.org.uk/DorsetWildRivers