Qing Ya Zi Options Appraisal Project

Description

The principal aim of this project is to carry out an options appraisal for fish/eel passage and habitat restoration opportunities at Qing Ya Zi on the River Itchen.
Brambridge Lock is a large structure spanning the Itchen Navigation at SU4681722613. It incorporates undershot sluices and an eel / fish trap and is in poor repair. It impedes free passage for migratory fish, and there are signs of a previous eel pass having been installed that no longer functions.
The structure is not an EA asset and is within the landholding of Qing Ya Xi. The head drop over the structure is ~1.5m with the impoundment extending approximately 1 km upstream, influencing several offtake structures including; to Rosemary's Leet at SU4718622977, to the main River Itchen at SU4718423034, and potentially the Southern Water Service's (SWS) surface water abstraction at SU4703823264.
Given its current state of repair there is a risk the structure will fail without intervention and the resultant loss of water level would have significant consequences for the upstream environment, including important SSSI wetland habitat that supports the protected Southern Damselfly plus a range of terrestrial species. Reduction in water levels may also have a negative impact on the stability of the artificial banks. Maintenance of water levels within the Navigation is a particular concern, for environmental, economic, and heritage interests. This is particularly relevant for the true right bank along which the Itchen Way footpath (a public right of way) runs.
At the downstream end of the project area, an artificial rock ramp impounds Rosemary's Leet which could otherwise provide a valuable alternative route for salmonid migration. The lack of attractant flow as a result of the impoundment, and the substantial sedimentation of the channel in the mid-section of the leet, is one probable cause for poor records of salmon use of this otherwise suitable channel. Easing passage for chalk stream salmon is a particular focus of the Itchen Salmon Delivery Plan which helps address the poor numbers of salmon returning to the Itchen - currently around 40% of those needed to meet conservation limits.

Controlling the removal of this significant impounding structure along with providing a more natural hydrological regime will improve conditions for a range of priority species and habitats.
To confirm the project reach for this options appraisal is from SU4702023575 & SU4725223529 (upstream) to SU4668222207 (downstream).