Green bank engineering using willow is a well-established technique on rivers across the UK. The approach uses long lengths of willow known as whips to weave around live willow stakes hammered into the riverbank. This approach known as spiling creates a strong barrier of living willow which diffuses the energy in the river or stream and reduces its impacts on the riverbank. Overtime these willow whips root and begin to grow, further securing their hold and that of the unstable riverbank. Using willow spiling has multiple benefits primarily stabilising riverbanks and reducing erosion, however this technique also creates cover and habitat for a myriad of fish species and life stages as well as invertebrates and other riparian wildlife.
On the Don we have been utilising locally won willow across several sites over the past few seasons with great success. However, we have been limited by the availability of materials to date and only managed to tackle small sections in the proximity of existing willow. Now thanks to Leys Estate who have supplied surplus willow material to the Don DSFB, we can now undertake larger and more significant sections of the catchment using this technique with excellent materials which would have been considered as waste.
Some images below illustrate the works undertaken at a site in Alford where significant bankside erosion was impacting spawning substrate. Coupled with bankside fencing this technique has already established well within a few months of installation having totally transformed the riverbank from a badly eroded bank bare bank into a lush thriving habitat.