Case study:Wild Wylye Phase 1

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Location: 51° 7' 55.89" N, 1° 55' 15.93" W

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Project overview

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Status	Complete
Project web site
Themes	Environmental flows and water resources, Fisheries, Habitat and biodiversity, Monitoring, Social benefits
Country	England
Main contact forename	Martijn
Main contact surname	Antheunisse
Main contact user ID	User:Martijnantheunisse
Contact organisation	Wiltshire Wildlife Trust
Contact organisation web site	http://www.wiltshirewildlifetrust.org
Partner organisations	Environment Agency, Wylye Fly Fishing Club, Natural England
Parent multi-site project
This is a parent project encompassing the following projects	No

The Wylye used to be over wide and straight, particularly on this stretch. Brushwood structures installed alternating on both banks have helped recreate (in-channel) sinuostity.

Project summary

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The overarching goal of this project was to enhance the river habitat quality of the Wylye over a length of 2000m. Within five years from project completion, once the effects of structures and planting have maximised, the river will provide a complete configuration of high quality habitats for key-species (i.e. Atlantic salmon, ‘wild’ Brown trout and River water-crowfoot), in all their lifecycle stages, but also incorporating the needs of a whole raft of supporting species. In addition, the river will provide a better, more challenging ‘wild’ fishing experience, the Wylye valley will be perceived as a more natural, aesthetic river landscape by river-owners and users and the whole system will be more resilient to short term incidents (droughts, floods) and long term changes (rising temperatures due to climate change).

A very important driver of this project was to bring together different stakeholders and interest groups on the river to make this project into a synergistically resounding success. Funding for the project come from the riparian owners, the Environment Agency and the Wylye Fly Fishing Club (WFFC). There was a contribution in time, free of charge, from WFFC and the Wessex Chalk Streams Partnership (hosted by Wiltshire Wildlife Trust, supported by the Environment Agency, Natural England, Wessex Water and the Wiltshire Fisheries Association). These two core partners have also provided and supported volunteer labour during the delivery process. Additional funding for specific parts of the work came from the Woodland Trust. The involvement and engagement of such a diverse group of organisations, people and professions ensured that we did not focus on just one specific outcome, but took all points of view into account. Furthermore, volunteers physically working on river enhancement projects took pride in their work (see the image gallery) and developed a feeling of ‘ownership’.

At the end of the project we had installed more than 60 ‘soft-engineering’ structures, ranging from simple log deflectors to large brushwood mattresses. Furthermore, we re-build riffles (by introducing fresh gravels) and we re-aligned the channel at two occasions.

Monitoring surveys and results

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Whilst empirical evidence relating to the success of the project is not yet available – the project was only finished by the end of 2014, certain indications were noticed within weeks of project completion and these suggest that we have achieved many of the goals set for the project.

For example, in more than 10 areas where structures have been installed to increase bed dynamics and re-energize erosion-deposition equilibriums, the evidence of scour, cleaning and sorting of gravels by the river is already clearly visible.

We cannot yet prove that this has led to an increase in fish spawning, but we can show that the gravels are now suitable for that purpose, whereas before they were concreted. Similarly, the dozen of brushwood structures installed to trap sediments and narrow the channel are clearly doing so. There is a higher flow velocity around the structures and the accretion of silt within them, is clearly visible. This has created in-channel sinuosity with the structures (woody debris and brushwood mattresses) deflecting flow from bank to bank from what was a uniform flow.

Further indication that the river restoration has already had a positive impact has been provided by chance meetings with fishermen on the river bank. Feedback has taught us that the fishing has become much more varied in the months after the work was delivered: a greater number of productive fish lies and much more variation in habitat and higher numbers of Grayling caught.

A more thorough evaluation of the project can (and will) be undertaken in the next year(s), when results from several monitoring efforts will become available. Prior to the project a topographical survey of the river bed and banks was undertaken. This survey will provide a baseline comparison when we repeat this survey in two and five years’ time. That will tell us whether we have indeed increased variation in channel morphology.

The long running Environment Agency programme for Atlantic salmon redd counting on the river will be continued. This will enable a pre- and post-project comparison of redd location and abundance telling us whether we have improved spawning conditions.

Repeated Fixed Point Photography (FFP) is being used to assess the establishment and development of river enhancement structures – such as hinged willows. Photos are taken at least twice a year. Although in itself very valuable, FPP cannot be used to evaluate the actual success in terms of reaching SAC, WFD targets. Data from biological monitoring are essential for that. Ultimately WFD and SSSI monitoring carried out on larger spatial and time scales will answer whether this project has contributed to the water body meeting these objectives.

Lessons learnt

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We did not encounter any major issues. Yes there were small hiccups during the delivery side of things (wrong gravel delivered, last-minute change of contractor), but not something that truly endangered the project.

The approach we took - project delivery mainly by volunteers - was so successful that we will endeavour to make that an important part from all future projects.

Image gallery

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Large Woody Debris Secured on the inner bend propagates sedimentation, eventually leading to channel narrowing.

Large scale ‘hinging’ of willows to provide additional in stream habitat.

Looking upstream before the work…

... same view after the work.

Re-opening of a back-channel provides shelter for juvenile fish.

Small in-stream structures can have significant effect on low-discharge flow patterns

Securing a log deflector to the riverbed.

During the process: narrowing at one side of the channel has already been undertaken (by installing a brushwood mattress), now waiting for the digger driver to finish the job by…

… bank regrading to finish small scale channel re-alignment.

Bed raising by introducing new gravels (from a local quarry).

Volunteers and tools ready for a day’s work on the river.

Volunteers building a natural revetment out of hazel screens to narrow the river and in the process remove rubbish (radiators) used as river bank protection.

Catchment and subcatchment Select a catchment/subcatchment Edit the catchment and subcatchment details (affects all case studies in this subcatchment) Catchment River basin district South West River basin Hampshire Avon Subcatchment River name Wylye (Middle) Area category 100 - 1000 km² Area (km2) Maximum altitude category 200 - 500 m Maximum altitude (m) 247247 m <br />0.247 km <br />24,700 cm <br /> Dominant geology Calcareous Ecoregion Great Britain Dominant land cover Arable and Horticulture Waterbody ID GB108043022550 Other case studies in this subcatchment: Langford Lakes project Site Edit site Name WFD water body codes WFD (national) typology WFD water body name Pre-project morphology Reference morphology Desired post project morphology Heavily modified water body National/international site designation Local/regional site designations Protected species present Invasive species present Species of interest Dominant hydrology Dominant substrate River corridor land use Average bankfull channel width category Average bankfull channel width (m) Average bankfull channel depth category Average bankfull channel depth (m) Mean discharge category Mean annual discharge (m3/s) Average channel gradient category Average channel gradient Average unit stream power (W/m2) Project background Edit project background Reach length directly affected (m) 20002,000 m <br />2 km <br />200,000 cm <br /> Project started 2014/01/01 Works started 2014/08/16 Works completed 2014/10/31 Project completed 2015/03/01 Total cost category 50 - 100 k€ Total cost (k€) 8181 k€ <br />81,000 € <br /> Benefit to cost ratio Funding sources Environment Agency, landowners Cost for project phases Phase cost category cost exact (k€) Lead organisation Contact forename Contact surname Investigation and design 1 - 10 k€ Wiltshire Wildlife Trust Martijn Antheunisse Stakeholder engagement and communication 1 - 10 k€ Wiltshire Wildlife Trust Martijn Antheunisse Works and works supervision 50 - 100 k€ Wiltshire Wildlife Trust Martijn Antheunisse Post-project management and maintenance 1 - 10 k€ Wiltshire Wildlife Trust Martijn Antheunisse Monitoring 1 - 10 k€ Wiltshire Wildlife Trust Martijn Antheunisse Supplementary funding information The capital costs (and part of staff time) was funded by the Environment Agency and the landowners. The two main project partners (Wylye Fly Fishing Club and Wessex Chalk Streams Project - hosted by Wiltshire Wildlife Trust) provided staff time in-kind. The total value of volunteer labour was conservatively estimated at £9250 (appr. 12500 EUR) Reasons for river restoration Edit reasons for restoration Mitigation of a pressure Hydromorphology Quantity & dynamics of flow, Width & depth variation, Continuity of sediment transport Biology Fish Physico-chemical Nutrient concentrations Other reasons for the project Measures Edit Measures Structural measures Bank/bed modifications Bed-raising, rebuilding riffles Floodplain / River corridor Lowering of floodbanks Planform / Channel pattern Channel realignment, Introducing large woody debris, Deflectors, in-channel remeandering Other Non-structural measures Management interventions Influence management by fisheries manager Social measures (incl. engagement) Involve local community with delivery, involve Well-Being group with delivery Other Monitoring Hydromorphological quality elements Edit Hydromorphological quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Channel pattern/planform Yes Yes No Yes No Awaiting results Width & depth variation Yes Yes No Yes No Awaiting results Biological quality elements Edit biological quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Fish Yes Yes No Yes Yes Awaiting results Physico-chemical quality elements Edit Physico-chemical quality elements Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Any other monitoring, e.g. social, economic Edit Other responses Element When monitored Type of monitoring Control site used Result Before measures After measures Qualitative Quantitative Monitoring documents Upload monitoring documents Additional documents and videos Upload additional documents Maps with the final designs A selection of social media interactions during the project Additional links and references Edit links and references Link Description Supplementary Information Edit Supplementary Information