The Oakley Stream is a modified channel forming part of the Middle Test SSSI Unit 89. This unit was assessed as Unfavourable – no change. The assessment cited the following as reasons for unfavourable status;
- The unit did not comply with river profile or river plan-form targets;
- The unit did not comply with either the river bank vegetation or the riparian zone targets.
The restoration of the Oakley Beat was driven by the recommendations of the Test and Itchen Restoration Strategy undertaken by Atkins in 2012. The aim of the recommendations was to rectify bed gradient of the long-river profile by bed raising and removal of impounding features, and to improve the channels habitat features.
The project was further informed by bed level surveys and water level calculations undertaken by Southampton University who used cutting edge GPS hydrological data gathering craft.
A 10m impounding weir was removed by hand from within the channel by water safety trained Aquascience staff and the adjacent river bed was re-profiled. 55m of the left hand river bank was scraped using a 14t excavator, the bank profile was regraded in order to allow better access for anglers.
A 40m gravel bar required 350mm of angular gravels to be removed after being raised too high by previous works carried out by another contractor. Aquascience re-profiled the gravel bar to reduce the invert level and used the generated material from this scrape to extend the bar downstream. Finally, 1600t of bed gravel were imported into the channel using a 30t long reach excavator moved to specific stationary positions on large bog mats, minimising disturbance to the embankment. Finishing and tidying of the new gravel bar was completed by the 14t excavator working within the channel.
The project was successful in its aim of reprofiling the river bed channel and moving the river reach towards favourable condition.