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The existing flood embankment provides an important role in reducing flood risk in Calstock, but surveys have shown it is in a poor condition. The Environment Agency is working hard to try to develop an affordable scheme to continue the standard of flood protection to properties within Calstock.
The Environment Agency carried out ground investigation and topographic surveys as well as heritage and ecological walkover surveys in autumn 2017. It used this to develop a hydraulic model and build an understanding of flood risk and the environment in Calstock.
The Environment Agency held a public drop-in in November 2017 to understand what the community of Calstock think about flood risk. The feedback, ideas and local knowledge have helped the Environment Agency design a scheme for people who live and work in Calstock.
If you missed the drop-in or would like to revisit the display materials, they can be viewed on Flickr. Please note that these drawings/information presented have been subject to change following the public drop-in as the design has developed and your ideas have been incorporated.
The Environment Agency listened to the feedback you gave in November 2017 and worked hard to see how its proposals could be adapted to align with the aspirations of the community. This has meant carrying out additional surveys, site visits and computer modelling as well as meeting with the local MP, parish council and individuals in the community.
The only way to fund a scheme that manages flood risk is to create reed bed habitat, as the latter provides approximately 75% of the funding for the work. A significant proportion of people welcomed the opportunities that the proposed habitat presented to attract wildlife to the area. However, a number of concerns/queries were also raised.
Will the habitat develop into reed bed or would it be muddy, unsightly and smell?
The Environment Agency carried out further work with its ecologists and other specialists as well as site visits to recently created areas of habitat upstream on the River Tamar. These demonstrate that the fields are highly favourable for the development of reed bed habitat. Reeds already grow on the margins of the existing flood bank and in ditches around the fields. Upstream examples of habitat creation suggest reeds will establish within 6 months and good coverage will be achieved within 2 years.
Will the intertidal habitat area attract flies and mosquitoes?
Environment Agency ecologists have looked at this and consider that the proposed reed bed is no more favourable to mosquitoes than the existing field. This is because the reed bed with its creek network will support a more diverse population of predators which will control insects – again this is confirmed by recent visits to local sites and discussions with landowners. Flies will be less prevalent on site as these are attracted by livestock which will no longer use the site following the creation of the habitat.
Will the reed bed habitat attract rats?
Reed bed habitat is not a favourable habitat for rats – these are attracted to landfill waste and livestock foodstuffs neither of which will be present within any area of habitat created.
The current footpath is permissive rather than a formal public right of way. At the drop-in event in 2017 the Environment Agency showed 2 potential options to try and ensure that a permissive path was maintained in some form. The options presented included an inland route and a route along the existing bank requiring a bridge (which the Environment Agency is not able to fund).
Residents had a strong preference for being able to continue to use the existing bank, the Environment Agency therefore asked its engineers to consider alternatives to a bridge and believe that a raised timber walkway could provide a suitable solution. The Environment Agency obtained a quote for the construction of a raised timber walkway and offered a contribution to the community so that it can be delivered and managed into the future (alongside the footpath itself) by the community/parish council. The Environment Agency also highlighted the opportunity for the community to take ownership of this pathway so that it could be designated as a public right of way – safeguarding the walk for the community into the future.
The field which is used informally for the annual bike show event was significantly impacted by the proposal put forward at the November 2017 drop-in. The Environment Agency heard of the importance of this to the local economy and community as a whole and is keen to ensure that there is still an area which may be available to hold community events following any proposed scheme. The alignment of the new flood banks was altered so that the key field is on the dry side.
Concerns were raised that the proposed work would be affected by any future discharge of sewage either from Harewood Road or from the wastewater treatment works itself. Changes to the waste water network are outside the scope of the project. However, concerns of unresolved pollution issues have been passed to both the Environment Agency’s enforcement team and South West Water. The proposed work will not increase the risk or impact of pollution incidents and by protecting the wastewater treatment works from flooding, the risk of environmental incidents will decrease.
The scheme will:
- protect community assets and reduce the risk to life which would result from a sudden failure of the embankment
- increase biodiversity through the creation of the area of intertidal habitat, which will be managed for the benefit of wildlife and local amenity
- support the community to construct and manage a crossing structure (enabling the continuation of the permissive footpath) by offering a financial contribution, materials and advice. The Environment Agency is also supportive of the path being designated as a Public Right of Way on completion of the project
- make the field adjacent to the football pitch available to the Tamar Community Trust such that it can be managed to the benefit of the local community
Planning permission was granted on 25 June 2019. This was a month later than was anticipated. However, the Environment Agency was not able to progress with work because the planning permission from Cornwall Council included a condition that the Environment Agency was unable to discharge due to the statutory limitations of its remit.
The Environment Agency has now received assurances from Calstock Parish Council that in the unlikely event that Tamar Community Trust is unable to maintain the redundant bank and footbridge, the parish council will use all reasonable endeavours and costs to undertake this maintenance. This agreement helps the Environment Agency discharge the problematic planning condition, providing a way forward for the scheme.
Calstock Parish Council has also agreed to take on the ownership of the section of the existing embankment which will no longer form a flood defence, but will continue to carry the existing permissive path. This is fantastic news as it puts control of this important local asset into the hands of the community, safeguarding it for the future.
The Environment Agency really appreciates the efforts that Tamar Community Trust and Calstock Parish Council have made in helping make the Calstock flood defence improvement scheme possible. It is also grateful for the key role the Tamar Area of Outstanding Natural Beauty (AONB) has taken in making sure the best outcome is delivered for the community, and acknowledges the continuing support of Cornwall Wildlife Trust and Calstock Footpath Society.
The outcome of this collaborative working means:
- Calstock will secure much needed investment in flood defences to protect properties, infrastructure and amenities in the village
- the Tamar Community Trust will construct and maintain the new bridge structure over the breach
- by taking ownership of the existing bank the parish council has safeguarded the riverside walk for the future
- intertidal reed habitat will be created in the existing fields attracting wildlife and supporting biodiversity in the area which will be managed by the Cornwall Wildlife Trust
- the field adjacent to the football pitch will be managed by Tamar Community Trust to the benefit of the community, helping to fund the maintenance works
The need to get a solution to the planning condition has meant that the Environment Agency has lost an additional month from its programme in the driest part of the year and as such the delivery of these works this year will now be even more challenging.
Work to reduce the risk of flooding to the community of Calstock is nearing completion. This means that there is a new more resilient defence protecting homes and community assets.
The Environment Agency has also created a habitat area with pools and creeks, which will support biodiversity, absorb carbon, off-set some of the impacts of sea level rise and provide a new amenity asset for the community.
Whilst the main construction work is nearly complete, there is still more to do. The Environment Agency plans to monitor and in places top-up the new banks as they consolidate. After the Tamar Community Trust have constructed the footbridge, the Environment Agency will return for 2 weeks to breach the former flood embankment; this is currently planned for October 2021. This will enable the habitat area to develop into a tidally-influenced reed bed, providing the benefits highlighted above whilst also enabling the continuation of the existing riverside foot path.
There are other benefits to the work: Calstock Parish Council are to take ownership of the former flood bank securing its future as a footpath for the community. The Environment Agency has agreed to lease land outside the habitat area to Tamar Community Trust so that this can be managed for local events and for the benefit of the community and the environment. First however, the Environment Agency plans to create a pond which can be used for ‘pond dipping’ by Calstock Primary School.
The Environment Agency thanks the community and partners Tamar Community Trust, Tamar AONB and Calstock Parish Council for their continuing support.