Case study:Swindale Beck Restoration: Difference between revisions
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Revision as of 10:08, 10 November 2016
Project overview
| Status | Complete |
|---|---|
| Project web site | http://https://naturalengland.blog.gov.uk/2016/10/13/putting-the-bends-back-into-swindale-beck/ |
| Themes | Fisheries, Flood risk management, Habitat and biodiversity, Hydromorphology, Land use management - agriculture, Monitoring, Water quality |
| Country | England |
| Main contact forename | Lee |
| Main contact surname | Schofield |
| Main contact user ID | User:Leeschofield |
| Contact organisation | RSPB |
| Contact organisation web site | http://www.rspb.org.uk/ |
| Partner organisations | RSPB, Environment Agency, United Utilities, Natural England |
| Parent multi-site project | |
| This is a parent project encompassing the following projects |
No |
Project summary
A partnership project by RSPB, EA, UU & NE to re-meander a historically straightened section of the Swindale Beck, an upstream sub-catchment of the River Eden in Cumbria. The channel had been straightened at least 160 years ago, appearing on the 1859 Ordnance Survey map in its straightened position. The beck was heavily rock armored on both sides with pronounced levees resulting from generations of farmers clearing it out and depositing material on the banks. These resulted in the straightened channel being effectively cut-off from the surrounding floodplain which not only accelerated flow through the valley, but also meant that when the banks were over-topped, water wasn't able to flow back into the channel and pooled on the meadows either side reducing their value both botanically and agriculturally. The straightened channel was very uniform both in terms of width and depth and bed substrate size. There were no riffles, gravel bars or pools within the straightened channel. Smaller gravels and silts were regularly carried during high flows and deposited at the drinking water intake immediately downstream.
In addition to the obvious engineering present in the channel, there was further evidence that the river had been modified in the shape of many paleochannels visible in the surrounding grassland. Using these, and detailed topographic mapping, a more appropriate route was designed by EA geomorphologists. Much of this new/restored route ran through areas of permanently wet and relatively species poor parts of the surrounding grassland. By reinstating the straightened channel after in-filling as hay meadow, the area of botanically rich and agriculturally utilizable land has been increased in the phase 1 area of the project.
Part of the new route of the channel ran through a SSSI hay meadow, so measures had to be put in place to protect this area. These included not storing any excavated spoil on the SSSI and only allowing machines to track within the footprint of the channel and on a specifically created haul route of bog mats and terram membrane. While these measures increased cost and complexity of the project, they were highly effective at protecting the SSSI meadow.
Work started in March 2016 and was completed in September 2016. The project resulted in 890m of new/restored sinuous channel being created, replacing a 750m length of straightened channel, so a gain of 140m in length. A further 110m of smaller sinuous channel was also created to connect two tributaries into the restored route. A relatively simple channel was dug by contractors, entrusting natural process to create specific in-channel features and morphological variation. This has happened with incredible speed. A significant rainfall event two days after connection of the first phase of the work helped to form new gravel bars, riffles and pools and populated parts of the new channel that were somewhat lacking in gravel with material from upstream. The new channel is already considerably more morphologically diverse than the straightened route and we are confident that increased ecological diversity will follow. The photographs give a flavor of diversity of the restored channel.
The old channel was in-filled and re-seeded with brush harvested seed from the SSSI meadow.
A bridge was removed as part of the project, and to enable access across the new channel, two ford crossing were installed. These will allow the river more potential for movement than bridges would. Crossing will only be required when hay is due to be cut, so the fords will likely only be used less than 10 times per year.
A further 436m of channel upstream of the main restoration area also had work carried out. This reach, although also rock armored and embanked had greater sinuousity, so instead of creating a new/restored channel for it, a less-interventionist and lower cost approach was taken. Key sections of the rock armored banks were removed by an excavator working from the bankside. The rocks that were removed were placed in the channel to create riffles. This work immediately added morphological diversity to the channel and will enable the river to further weaken remaining sections of the banks over time.
Whilst contractors were on site, the opportunity was taken to block up artificial drains on an adjacent area of valley mire, further contributing to slowing the flow of water through the valley.
Fencing the channel and tree planting are not compatible with the SSSI interest features, but in the phase 2 part of the project which falls outside of the SSSI, tree planting within a fenced river corridor was carried out. This will mean that roughly half the length of the restored channel will be wooded with the other half open. The surrounding meadows are managed in a traditional way with light sheep grazing and no spreading of manure or artificial fertilizers and no pesticides are used.
The restoration of Swindale Beck fits within a wider set of works that are helping us to use the valley to demonstrate a broad range of management techniques that can be considered as best practice land management for flood alleviation. In the highest part of the catchment, through their Sustainable Catchment Management Programme (SCaMP), United Utilities have restored a significant area of Mosedale, the Lake District's largest area of blanket bog. In this area, 47km of grips have been blocked and all livestock have been removed for a 10 year period. A number of other areas of bog and mire within the Swindale catchment have also been restored through grip blocking in recent years. Also through SCaMP, approximately 40,000 trees have been planted in Swindale and many small watercourses have been fenced to encourage natural riparian woodland regeneration. The drinking water intake just downstream of the restored section of Swindale Beck has recently been replaced, incorporating a new fish pass and features to benefit the downstream section of the river (part of the Eden & Tributaries SAC). We are also developing plans to create two areas of flood water storage in Swindale. There can be few places in the UK where such a range of interventions are being carried out within such a small area. A robust monitoring and research package is being developed to ensure that the maximum range of benefits are captured.
The Swindale Beck Restoration Project has received a great deal of attention both locally and nationally and we have hosted a large number of visitors to come and see the work over recent months. It has been featured in a range of media publications, e.g. https://inews.co.uk/essentials/news/environment/mankind-helping-lake-district-river-meander/ A short film has been produced about the project by Unitied Utilities (https://www.youtube.com/watch?v=jt2pdqnYmJc)and we plan to produce a more detailed film in spring to help disseminate the benefits of river restoration projects.
A new permissive footpath and on-site interpretation will be installed to help visitors to the valley understand what has been done and why.
Swindale valley forms part of RSPB Haweswater, land managed by the RSPB and owned by United Utilities. RSPB and UU are working in partnership to improve biodiversity and raw water quality alongside other ecosystem services. Further information about our work at Haweswater can be found here - http://www.rspb.org.uk/Images/HWR-0629-15-16%20Haweswater%20management%20plan%2016pp%20low%20res_tcm9-412269.pdf
Monitoring surveys and results
Lessons learnt
Image gallery
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Catchment and subcatchmentSelect a catchment/subcatchment
Catchment
Subcatchment
Site
Project background
Cost for project phases
Supplementary funding informationMain Contractor cost for delivery - £205,000 Geomorphological clerk of works - £6,200 Access & Interpretation - £2,000 Staff time for partner organisations is not included in these costings.
Reasons for river restoration
Measures
MonitoringHydromorphological quality elements
Biological quality elements
Physico-chemical quality elements
Any other monitoring, e.g. social, economic
Monitoring documents
Additional documents and videos
Additional links and references
Supplementary InformationEdit Supplementary Information
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