Woodgreen - Demonstrating strategic restoration and management STREAM (LIFE05 NAT/UK/000143)
Woodgreen - Demonstrating strategic restoration and management STREAM (LIFE05 NAT/UK/000143)
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The FORECASTER Team
Key features of the case study
In the following section, background and motives of the restoration project which led to the initiation of the project are introduced
Drivers and pressures
The river Avon and its catchment faced many threats during the last decades. Aiming to turn wetlands into arable land, drainage were undertaken thus resulting in many parts of the river channels being widened, deepened and natural bed material removed. The river ecosystem also faced nutrients pollution due to an agricultural intensive use of fertilizers as well as significant water abstraction. Although agriculture was considered as the main human pressure, public water supply & sewage, diffuse pollution from tracks, roads, fishery management, etc. also affected the Avon river ecosystems.
Despite all those threats, the river Avon and its tributaries still contains some of the most rare threatened species and habitats in Europe and were thus designated as a Special Area of conservation (SAC) while the Avon Valley was designated as a special protection area (SPA) for birds (NATURA 2000). To protect those threatened species and habitats, a conservation strategy for the River Avon SAC was undertaken in 2003 to identify measures in place to address the impacts, but also gaps where new actions were needed. This conservation strategy generated two major partnership projects:
- the STREAM LIFE-Nature Project focusing on restoration of the river Avon SAC,
- the Living River Project which focused on wider biodiversity of the River Avon system and on engaging communities in its conservation.
A range of other projects were also underway to address threats to the river and its valley such as The River Avon Landcare and Catchment friendly farming addressing diffuse pollution as well as the advisory services of the Wessex Chalk Streams project and the Forest Friendly Farming project.
The Woodgreen on the river Avon restoration were undertaken in the framework of the LIFE project STREAM among five others restoration sites: Amesbury on the river Avon, Chilhampton on the river Wylye, Fovant on the river Nadder, Blashford on the Dockens Water, and Upper Woodford on the river Avon.
Global objectives
The LIFE project STREAM aimed to address the pressures inflicted upon river ecosystems by restoring habitats in River Avon and Avon Valley for protected species but also by integrating the management of the river and valley to the whole restoration planning.
Specific goals
In order to achieve those objectives, the STREAM project board set specific goals before implementing any restoration measures, which are introduced below.
First of all, the project planned to integrate the management valley to the whole restoration planning by addressing the effects of past engineering and land drainage and by demonstrating innovative techniques and proven habitat enhancement methods.
The project also foresaw to restore suitable conditions for the River Avon SAC habitats and species. Details of how the project was planned specie by specie are introduced below:
- River habitats improvement for the plant community by creating more suitable habitats through an increase of flow speed and cleaning gravels.
- Improvements of habitats for Bullhead (Cottus gobio) by developing ways to introduce and retain woody debris.
- Increase of the availability of habitats for Desmoulin's whorl snail (Vertigo moulinsiana) and work with Living River to remove invasive plant species.
- Establish more appropriate water level management in the Avon Valley for the Bewick’s swan (Cygnus columbianus) by developing hatch operating protocols and a ditch restoration programme.
- Establish more suitable habitat for breeding and for young Atlantic salmon (Salmo salar) and develop guidance on measures to reduce entrapment and facilitate fish passage.
- Sensitive management of ditch networks in order to provide spawning habitat for brook (Lampetra planeri) and sea lamprey (Petromyzon marinus)
- Establish more appropriate water level management in the Avon Valley and increase understandings in the effect of human disturbance to protect the Gadwal (Anas strepera) population.
With regards to Woodgreen on the river Avon restoration site, the project aimed to bring back healthy populations of Atlantic salmon, rare sea lamprey, and river plants.
Site description
Measures selection
The following section introduces which measures were prepared, implemented and whether they were successful in reaching their related goals
A broad range of restoration measures were implemented in the frame of the LIFE project. In total, restoration work led to the creation of 0.36 ha of new spawning area for Atlantic salmon, bullhead and lamprey and the enhancement of approximately 7 km of river and banks.
Regarding to Woodgreen on the river Avon restoration site, part of the river bed was raised, existing gravel was reshaped and large woody debris was installed. Details of how the measures were implemented are introduced below.
- re-instating the gravel shallows in two places
- using deflectors to vary flow and clean the gravel bed
- coppicing some willows and planting riverside shrubs
In order to avoid damaging environmental effects during the restoration work, specific measures were put in place to minimize silt release and transport, disturbance to protected species and to ensure use of local materials.
Success criteria
Regarding to the whole LIFE project, although no biological targets were used since it is difficult to set meaningful criteria when monitoring only for 2 years, suitable spawning area targets were set by estimating how much spawning gravels could be created.
Ecological response
Because rivers are complex and take several years to respond to restoration, it is not possible to draw any definite conclusions yet. However, there are encouraging signs that have already highlighted STREAM project restoration successes such as improvements in the plant community at all six restoration sites with the settlement of the water crowfoot (Ranunculus aquatilis) as well as more marginal habitats observed in the riparian zone. Precise results site by site are available here [1], [2] and [3]
Hydromorphological response
Hydro-morphological encouraging signs were seen through improvements in the gravel river bed at all six restoration sites. More spawning gravel beds were actually created than foreseen.
At Woodgreen on the river Avon, the main bed raising created good flow diversity, providing spawning habitats for fish. The reshaped gravel has also created habitats diversity. The woody debris is creating local flow variation. Nevertheless, despite observed encouraging signs, some issues remain and the state restoration work could be improved. More, bigger woody debris would be needed to be effective. Practical limitations such as the availability and size of large trees that can still be moved with machinery may limit the use of woody debris in deep wide channels.
Monitoring before and after implementation of the project
Monitoring against project aims was considered as a key issue to evaluate how successful the restoration has been, and to identify any problems with the restoration techniques used while carrying the LIFE project. Hence, a programme of survey and monitoring were carried out as part of the of the STREAM river restoration work by an independent organization. All six rivers restoration sites were then monitored pre and post restoration. The surveys investigated the restoration works and identified their possible influence on physical habitats and ecology on the sites by collecting the following data:
- Physical Biotope Mapping and Fluvial Audit
- River Corridor Survey
- Repeat Fixed Point Photography
Besides, specific data were also collected at two reference sites that both have comparable gradient, width and flow to restored river stretches. Those two reference sites (Upper Woodford control site and Seven Hatches control site) are slightly more natural but project board pointed out that it is almost impossible to find a pristine reference site.
- Channel cross-section survey
- Physical habitat survey and depth
- Velocity and substrate measurements
- Detailed macrophyte survey
- Fisheries survey
The detailed monitoring protocol is available here [4]
Even though a large monitoring was carried in the frame of the LIFE project, the project board faced constraints such as timing and funding. Timing made it tricky to collect long-term pre-data as LIFE funding were only received 6 months before the official project start. Besides, funding was not available to carry a relevant post-restoration monitoring to find out river restoration successes.
In addition to the monitoring programme, an audit was also carried by the River restoration Centre (RCC). This audit aimed to assess the project design and objectives using expert judgments and the experience of the River Restoration Centre; it actually compared the work on the ground and the monitoring programme results with findings from other projects (reports available here [5]).
Socio-economic aspects
In the following section, ways of cooperation, interaction and information with partners, stakeholders and wider audience of the project are introduced as well as their related success in reaching their participation objectives.
A large participation process was developed in the frame of the LIFE project STREAM as introduced in the following table and further below.
Cooperation
The project built partnerships between several organizations with different backgrounds. Natural England was the project leader while the Environment Agency, Wiltshire Wildlife Trust, Hampshire & Isle of Wight Wildlife Trust and Wessex Water were partners. The LIFE project cooperation helped in building strong partnerships in the Avon catchment. Currently, those partners are still working together to undertake further actions.
Interaction
During the entire STREAM project, managers worked closely with the Living River Project which aimed to increase local people’s awareness and appreciation of the River Avon System. This interaction led to several achievements from the implementation of restoration (e.g., invasive plants forum and actions), to the development of best practices, or the education of communication part.
Furthermore, STREAM project board consulted local people, key stakeholders before carrying out the restoration works, explaining aims and expected results and giving them a chance to raise any concerns they may have. Landowners and fishery managers were involved in the project detailed design.
Communication
Besides restoration measures, the STREAM project aimed to share its experience at three different levels which are further down developed: other river restoration practitioners, local river users such as fishermen and landowners and broader general public. First of all, the project aimed to develop best practices and share them with landowners and anglers mainly with regards to the three following issues
- Identifying ways to stop fish species getting trapped in the valley ditch networks
- Developing a strategic programme of ditch restoration
- Developing operating regimes for key sluices in the river and valley
Project experiences and advices were compiled and shared in published guidance which is now used to achieve appropriate water level management at another 32 structures in the Avon catchment and are being used in other parts of the UK.
- Guidance on operating sluices and hatches which can be used to help manage water levels for river and floodplain habitats and species. Further details are available in the following reports: Taylor N. (2008) STREAM Action C2: Hatch Operating Protocols. Environment Agency technical Report and Guidance on Developing Structural Operating Protocols (2009)
- Planning floodplain restoration which is a way to plan floodplain restoration works whilst avoiding trapping fish in the valley ditch network. This involves using available fishery data to generate color coded maps, which are then used to assess the potential impact on fish of measures such as ditch reinstatement and new structures. Further details are available in Salomon D. (2007). Method for prioritizing fisheries in floodplain restoration
The STREAM project also aimed to share its experience, lessons learnt while carrying the project, with UK and European river managers and experts by publishing advices note:
- Advice note Planning River Restoration
- Advice note Linking River and Floodplain Management
- Advice note River restoration
Site visits, workshops and seminars (e.g., UK River Restoration Centre annual conference) with other rivers practitioners were also carried. Over a hundred river experts attended the STREAM international conference in July 2009. All the events gave people a chance to discuss technical aspects of the STREAM project, visit the restoration sites and pick up tips on how to restore Europe’s rivers.
Finally, besides the development of best practices, raising awareness of the river system and the project in the local community was also targeted. This public awareness were developed through project website, workshops, leaflets, posters, media publicity, open days and seminars, signs and display boards, layman’s report, community events, etc. The public joined successfully the project with more than 6000 people attending to the events, more than 17 000 people visiting the website and more than 700 volunteers participating in the restoration works.
Funding
The following section gives an overview of cost and funding of the project
Approximate cost: £1, 2 million
%EU Funding: 40%
%State: £980,000
%Water authority: co-finance £10,000
% Other partners: £27,000
Contact person within the organization
Nature England
Jenny WHEELDON, project manager/coordinator
Telephone: xxx
E-mail: xxxx
Extra background information
As introduced above, the ecological and hydromorphological state of the Avon ecosystems can still be improved. Besides, the project managers brought up the importance of the scale of a restoration project. They came up with the conclusion that the strict interpretation of SAC boundaries is not always the most beneficial for the SAC interest species/habitats. Implement river restoration measures at a larger scale (floodplain for e.g.) would actually be way more effective and cost-effective than simply limiting the works to a tightly defined river corridor. For those reasons, project partners decided to continue the restoration work at a larger scale through the implementation of long term strategy setting out the priorities for the future (available here [6])
The project team made available many technical lessons learnt from every site and some tips to improve river restoration knowledge as well as guidance in most of the reports available at [7]. Besides, specifics are available in the RRC audit report and Haskoning monitoring report.
References
- STREAM project website
- Project leaflet (language: English)
- Demonstrating strategic restoration and management of the River Avon SAC. Layman’s report (language: English)
Related Measures
- Establish environmental flows / naturalise flow regimes
- Initiate natural channel dynamics to promote natural regeneration
- Introduce large wood
- Develop riparian forest
Related Pressures
- Channelisation / cross section alteration
- Alteration of instream habitat
- Sedimentation and sediment input
