Two large weirs were impounding large sections of the River Beane, a chalk stream. Salix were appointed as principle contractor to create 1.5km of bypass channels via Affinity Water’s National Environment Programme framework.
The driver for the project was to improve ecological, hydromorphological and geomorphological processes.
River Beane is failing to meet Good Ecological Status under the Water Framework Directive. The River Beane is a chalk stream, which are globally recognised for their rarity.
Chalk streams are naturally very biodiverse, offering habitats to a wide range of species from macroinvertebrates to otter. However, the two weirs were having a detrimental impact on the natural function of the River Beane.
Weirs act as a physical barrier on watercourses which cause a significant number of issues for the natural processes. Weirs impound water, limiting sediment transport downstream and subsequently reducing the water quality behind the weir.
Weirs are also impassable to fish, which is particularly problematic salmonid species which instinctively swim upstream to spawn or reproduce.
What was the solution
Under the National Environment Programme, Affinity Water and the Environment Agency identified an opportunity to improve over 1.5km of watercourse through creating two bypass channels. Salix were appointed as principle contractor to provide a low carbon, nature-based solution.
Two bypass channels were constructed to improve the connectivity of the river. Pools, riffles and glides were formed to help initiate natural processes. Both weirs and the broadwater are listed, meaning bypass channels provided not only the best solution for the river, but preserved the heritage value. This solution has seen improvements to biodiversity as well as significant improvement in river function.
LiDAR data indicated that the River Beane had historically meandered through nearby pastureland. The Estate agreed to rearrange land use to accommodate for the restoration project, enabling the creation of the bypass channel whilst also retaining the heritage value of the weirs and broadwater.
What was the outcome
The site is being surveyed over the next 5 years to monitor its success, however the results from Phase 1 are already showing positive results, with the local Riverfly Group reporting 80% of species expected in a chalk stream.