cbec applied a full ‘process restoration’ strategy on a tributary of the River Dulnain, with the aim of reinstating dynamic geomorphic and ecological processes
We identified the dominant constraints to natural process and implemented associated measures to reduce these. This involved the addition of large wood and gravel augmentation and the removal of flood embankments. Assessments of sediment transport processes guided the optimal locations for gravel augmentation so that the introduced material could be redistributed throughout the site to create a new spawning habitat. High-flow events subsequent to construction have already begun a trajectory towards the desired physical and ecological state. This has included the development of alluvial (gravel) bar features, greater channel heterogeneity, increased lateral geomorphic process (increased sinuosity) and greater channel–floodplain connectivity. The development of gravel bar features has been associated with increased spawning habitat that has already been utilised by sea trout and Atlantic salmon. We will monitor the site over the next few years to quantitatively determine how the channel adjusts to the restoration works.
This project won the 2020 UK River Prize for reach scale project; details can be found here.