40. Cedar Close Weir Bypass Channel
Themes: Flow; Water Quality, Habitats and Wildlife
- That whatever the flow level, the river and its associated habitats, including banks and floodplains, are managed to support chalk stream species
Our preferred option to achieve the objectives of the project is a bypass channel within Millmead open space. This will follow the course of a relic channel, rejoining the river immediately downstream of the weir.
The main section leading from the upstream end will be designed to appear as natural as possible. Banks will have a natural gradient where possible, and the bed of the stream will be lined with gravels. There will be occasional pools and boulders to create diverse flow conditions and to aid the movement of fish, and the banks will be planted with native bankside plants.
A short second section adjacent to the weir will be more engineered, incorporating a technical fish pass and an eel pass. The fish pass uses baffles to create flow conditions which fish can move through on a relatively steep slope. The incorporation of a fish pass into the design enables the remainder of the bypass to have much more natural characteristics.
In association with the bypass channel construction and as part of wider habitat improvements we also propose some thinning of trees along the riverbank within the open space to allow more light to reach the river and further contribute to the diversity of habitats within the channel and along the riverbanks.