Nadder & Wylye at Quidhampton, Salisbury 2015

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Nadder & Wylye at Quidhampton, Salisbury 2015 The site The site at Quidhampton is 400m of the River Wylye and 1300m of the Nadder at their confluence near Salisbury (fig. 1). The upstream limits are at NGR: SU 10681 30924 (R. Wylye) and SU 10631 30777 (R. Nadder). The downstream limit is at NGR: SU 11659 30586. The land at this site is primarily owned by Wilton estate, and tenanted out to farmers and a local fly fishing club.

Process Time Process Time Stakeholder engagement Jul 2013 – Oct 2015 Channel survey Jan-Jul 2015 Invasive species treatment Jun-Aug 2015 Protected species survey August 2015 Design Jan-Sept 2015 Flood Defence Consent Sept 2015 Volunteer recruitment Aug-Oct 2015 Delivery Oct 2015 Monitoring Oct 2015 - ongoing Reporting Jan 2016

Fig. 1 - Map with site location marked Table 1 – timing of processes involved in delivery

Project Aim This project aimed to rehabilitate a stretch of the Rivers Wylye and Nadder, from Netherhampton road, to over 1km below their confluence at Quidhampton. Unsympathetic historic management of the river has led to overwidening and has made the channel profile more uniform. Additional historic bankside management (revetment structures) have also started to fail, at some points causing significant erosion behind the structures. This project is made up of parts of reaches N52 an W19 as identified in the Directory of Actions. This is part of the Strategic Framework for the Restoration of the River Avon, a document commissioned by a number of organisations to develop a strategic approach to getting the SSSI / SAC into favourable condition. Due to its priority (high) within this document, funding was forthcoming from the Environment Agency to assist in delivery of this project.

Overseen by Wiltshire Wildlife Trust’s Water Team, the project aimed to restore the channel morphology and create/enhance habitat for plants, fish, birds and mammals that are present along the river corridor. In addition to this, a number of potential spawning riffles had become compacted and silted up, making them unsuitable for salmon and trout to breed on. Part of the project’s aim was to restore the suitability of this habitat.

Wiltshire Wildlife Trust is a Company Limited by Guarantee and registered as a charity. No. 266202. Registered Office: Elm Tree Court, Long Street, Devizes, Wiltshire, SN10 1NJ. Limited Company No. 730536 (01380) 725670 | [email protected] | www.wiltshirewildlife.org facebook.com/WiltsWild @WiltsWildlife Wiltshire Wildlife Trust’s Water Team Project Completion Report

Delivery detail This project was instigated at the request of the Environment Agency, and with the support of the local landowners and the Wylye Fly Fishing Club, who lease the fishing rights to this reach. The designs were drawn up by WWT and the Wessex Chalk Streams and Rivers Trust (WCSRT). Funding was provided by WWT, the Environment Agency and the Catchment Partnership Action Fund (CPAF) (a fund awarded by DEFRA to the Hampshire Avon Catchment Partnership to deliver habitat improvement projects) . Delivery was undertaken by volunteers and independent contractors, led by WWT, as well as a representative from the Wild Trout Trust (WTT). The general theme of the works was the installation of large woody debris, brushwood berms and flow deflectors to narrow the channel, improve flow velocity and variability, create in-stream habitat and improve the channel’s resilience to extremes of high and low flow. Gravel cleaning was conducted on the riffles to loosen the gravel and remove silt, restoring its suitability for salmonid spawning. The tackling of the non-native, invasive species Himalayan balsam (Impatiens glandulifera) was also a central part of this project, as it outcompetes native flora and undermines the integrity of the river banks.

Stakeholder consultation was crucial in the on-going development of the project and the WFFC were involved throughout the planning and delivery process. Due to this consultation and the opportunities available, a bold and significant project was delivered which will have wide-ranging environmental benefits.

Fig. 2 Volunteers and stakeholders installing a brushwood berm (©WWT)

In all, a total of 73 interventions were implemented throughout the reach. The size and type of these interventions were bespoke to the localised conditions, but with an overarching view of what was needed within the reach as a whole. It is too early to see the full benefits of the project; however changes in channel morphology could be seen to be occurring even while the project was being delivered.

The removal of the failed revetments at the downstream section of the reach has been delayed until 2016 due to time and financial pressure, as has work on two cattle drinks which currently contribute to sediment inputs into the river; however once these are completed, this project will be a prime example of best practice chalk stream restoration.

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Wiltshire Wildlife Trust’s Water Team Project Completion Report

Due to the presence of a number of landowners along this stretch, stakeholder consultation was crucial in the on-going development of the project. As a result of this consultation, as well as the presence of a number of protected species (including bats, Water vole and Otter), designs had to be adapted several times during the project, leading to a bespoke, dynamic restoration which should be readily able to withstand the variety of pressures faced by the river. Monitoring

Monitoring of the site will consist of fixed point photography and long-sectional channel surveys, which were begun prior to project delivery. Invertebrate monitoring and fish catch recording will be conducted over a number of years by the fishing club. In this way, any changes in channel morphology and biodiversity will be picked up and provide an indicator for the success of the project. Project value

Contributors Value of Contribution (£) Environment Agency 29500 Wessex Chalk Streams and Rivers Trust 2500 Wiltshire Wildlife Trust 4747 Volunteer hours 1800 Total 38547

Expenditures Planning Delivery Comments Staff Time 7000 12824 Project management, volunteer management and training, in-stream labour Consultants 1120 Protected species survey Contractors 5900 Tree surgery and in-channel labour Materials and Other Site 9903 Stakes, wire, PPE etc. Costs Volunteer contribution 1800 Volunteer delivered in-stream works Total £8120 £30427 £38547

Summary Phase 1 completed. Revetment to be removed and cattle drinks installed in 2016.

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Wiltshire Wildlife Trust’s Water Team Project Completion Report

Appendix The table below provides a breakdown of the interventions used within this project, and the benefits expected to be gained from them. Details per structure Structure Materials Fixings Channel Flow Silt Habitat type narrowing deflection trapping creation

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