Agenda item

Natural Flood Defences - Presentations by Tom Cook (Environment Agency and Phil Williams (Natural England)


(1)       Both of the presentations for this item can be found in the electronic agenda papers for this meeting on the KCC website. 


(2)       Mr Tom Cook (EA Biodiversity Specialist) gave the first presentation.  He said that Defra had allocated £15m in 2016 to the EA for Natural Flood Management (NFM) across the UK.  £300k of this had been allocated to Medway NFM enabling the testing of nature-based techniques to contribute to the evidence base, whilst reducing the flood risk to properties, drawing in other funding, engaging with communities and delivering multiple benefits. 


(3)       Medway NFM was part of the Medway Flood Partnership.  It worked together with the South East Rivers Trust which was leading and co-ordinating delivery of the project which was currently match-funded by FRAMES (an EA interreg funded project) together with contributions from Maidstone BC and other partners (including KCC).   The EA also reported on the property benefits, biodiversity and landscape character, building up an evidence data bank for future NFM work. 


(4)       Mr Cook went on to say that the Medway Flood Partnership had begun its work by identifying the areas in the Medway where NFM would be most achievable.  The best place to start was in the upper catchment so that water could be stored before reaching the vulnerable villages and hamlets lower down.  The EA’s national mapping tool had been used to gather evidence, including mapping, elevations, soil types of all the water bodies.  This information was then mapped in conjunction with those properties which were known to be at risk.  This had yielded 10 water bodies located in the catchment area.  The South East Rivers Trust had then spent a great deal of time in discussion with local landowners as well as Natural England and other partners in order to ascertain where the monies could best be put to use during the project’s two-year life. 


(5)       The first project was at Bedgebury Forest, in partnership with the Forestry Commission.  This site had been planted with conifers over a period of a hundred years.  It had good drainage facilities which had enabled the landowners to maximise their profits.  The project involved slowing the waterflow by installing leaky wood dams to distrubute overflow on the forest land.  It would change the nature of the forest by enabling it to store more water.  It was an important demonstration site as it showed Forestry Commission staff what NFM could achieve.  At the same time, environmental surveys were being undertaken to assess the nature and level of change to the natural habitat.


(6)       The second demonstration site was at Sissinghurst Castle. The main partners were the National Trust who had a large estate beyond the gardens and had also decided to adopt NFM measures on their own land, locally and nationally.


(7)       Mr Cook explained that the EA’s site was at the Hammer Stream, which was an IDB watercourse where the riverbed lay some 3 metres below the flood plain, resulting in the water flowing very rapidly downstream.  The project had involved capturing some of the peak flow from the Sissinghurst Stream which joined the Hammer Stream on the estate.  The historic old channels were utilised to store water which was also able to infiltrate the soil.  Surveys had also been carried out to analyse the impact of the increased water on the soil’s quality.  


(8)       Mr Cook then said that the School Stream at Headcorn was the location of the third project.  A number of properties were at risk of flooding because, although the Stream was small, it was in a catchment area that was intensively used and had a high run-off rate from the escarpment – although it was prone to dry out completely during the summer.  A mature fallen willow upstream was almost blocking the watercourse and served an important NFM function.  South East Rivers had carefully mapped all the features, including pathways in order to develop the best site-specific option.  There had only been limited take up by the large number of landowners, but it was hoped to be able to adapt the pathways and install leaky wood dams and to encourage more landowners to participate as they saw the benefits occurring.   The work already carried out included digging out and extending a pond in order to increase its storage capacity.


(9)       Mr Cook said that the largest project was on the Alder Stream in Five Oak Green, where some 100 properties were at risk of flooding.  This was a very steep-sided valley of pasture and woodland.  A large proportion of the landowners were engaged and carrying out interventions.  The project involved the installation of several natural structures to slow down the water flow, which had proved successful during the recent storm events.


(10)     Mr Cook confirmed that the EA and the Forestry Commission had prepared a risk assessment guide for leaky wood dams to assess their safety.    


(11)     The outputs from the project were that the South East Rivers Trust had engaged successfully with landowners and developed two key demonstration sites.  It was hoped to secure further funding after it came to an end during the summer.  Meanwhile the data gathered would be collated in order to determine all its multiple benefits and would also be published on the internet.  The final report would inform the national debate about the role of NFM in flood prevention and mitigation.  


(12)     Mr Cook concluded his presentation by saying that the legacy of the NFM work with such organisations as Natural England, the Forestry Commission, the National Trust and the RSPB was that it would influence land management nationally and help inform targeting for future land management grants.  This was an opportunity to strengthen partnership working on water management to deliver multiple benefits to the communities. These included more drought and flood resilient farming, carbon offsetting, biodiversity and net gain through habitat creation as well as landscape and recreational benefits.


(13)     Mr Phil Williams (Natural England Conservation Advisor) began his presentation by explaining that that his purpose was to set out Natural England’s national policy on Natural Flood Management.  It was very important to ensure that NFM not only prevented or mitigated flooding, but also that it delivered significant environmental benefits. 


(14)     Mr Williams said that stakeholders had priorities which varied from the restoration of pristine wetland natural habitats on the one hand to hard engineering solutions on the other.  Natural England sought to persuade them that hard engineering would work better if more natural features were built into a project.  An example of this was that NFM could “de-synchronise” the discharge of tributaries into rivers.  If they could be made to discharge at different times, there would be a smaller peak downstream.


(15) Natural England was interested in NFM that was holistic, sustainable, integrated, based on the principles of natural function and which delivered for the natural environment.  It should not just use nature as an engineering material.  An example of what was not required would be the creation of a reservoir surrounded by bunds, failing to deliver anything for nature.


(16)     Mr Williams described Natural England’s pyramid of what constituted an ideal project. It should be based on natural function, understanding the causes of the flooding within the catchment.  It should recognise the effects of previous flood alleviation by mitigating sustainability and building natural capital.  It should identify and take advantage of opportunities for environmental enhancement. There would always need to be compromises which would need to be explained to the local communities.  The project would need clear objectives and expectations based upon the principles of nature and the way in which the catchment worked.


(17)     Mr Williams said that the evidence for NFM was difficult to quantify in the way in which hard engineering solutions could be measured.  The evidence was necessarily “soft” as it could not clearly demonstrate cause and effect.   Nevertheless, it was clear that NFM was effective for flooding at moderate scales and could deliver wider biodiversity to the eco system in general.  More research was needed, including monitoring of the impact of pilot schemes.


(18)     Mr Williams said that NFM could not solve flooding on its own but that it could help where there was a viability gap in funding more expensive schemes.  NFM was worthwhile for the sake of the wider benefits to the countryside.  NFM should be undertaken on a “no regrets” basis for this reason, even if it transpired that the expected flood alleviation benefits did not result. 


(19)     NFM was relevant on a large or landscape scale.  This was difficult to achieve if there were several landowners.  It was preferable (if not always achievable) to carry out an NFM approach that benefited the whole catchment.  It was also relevant from the headwater source to the sea.  An example of the latter would be the encouragement of saltmarsh development to help prevent coastal erosion.  SuDS was also an NFM solution as it held up water in a controlled way which prevented a “boom and bust” effect. 


(20)     Mr Williams then said that the NFM measures did not necessarily have to be put in place at the point where the problem showed.  Work should often start at the top of the catchment in all the tributaries so that the effects were beneficial further downriver.  NFM was not a competing land use. It could be integrated into the existing use of the land quite easily.   He added that NFM was “a layer cake not a pie.”


(21)     Mr Williams gave an example of NFM using a leaky woody dam.  It could be said that this was an example of a feature that was more ecologically functional providing less flood risk benefit.  He added that river morphology, involving re-instating meanders and bends was more useful than de-straightening them through hard engineering.  There was also a lot of scope for the re-connection of rivers with their plains because so much of the river had been embanked.  Wet woodland was a priority habitat because it had the effect of slowing water as it passed through the rough terrain.


(22)     Mr Williams said that he worked in Land Management and was experienced in discussing flood alleviation measures with farmers.  The first consideration was whether NFM such as riparian buffer strips could be employed to improve the functionality of their land holdings.  Natural England was always keen to show how conservation management could reduce flooding.  It also promoted landscape-scale delivery in its C21 Strategy Document.


(23)     Natural England responded to consultations on planning applications which might affect designated sites.  This enabled them to push for sustainable planning decisions and to promote a greed infrastructure approach.  They advocated the use of Net Gain as a tool to build in NFM.


(24)     Mr Williams concluded his presentation by summing up Natural England’s future work. They would continue to advocate NFM to the Government and push for NFM principles in the new Flood and Coastal Erosion Risk Management (FCERM) Strategy.  They were shaping the approach to NFM in the new Environment Land Management Scheme (ELMS) which would soon replace the Countryside Stewardship Scheme.  More locally, it would support local teams through the development of an NFM toolkit and continue   to provide advice to farmers on Catchment Sensitive Farming on how to reduce soil erosion and flooding on their land as well as on a landscape-scale.  Finally, they would continue to gather evidence to demonstrate the benefits of NFM in alleviating flooding, which had often been a result of hard engineering.


(25)        Miss Carey (KCC Environment Cabinet Member) asked whether there were any NFM techniques were not recommended.  Mr Cook replied that the data was still being evaluated. He could provide data on case studies for information. In general terms, cost benefit analysis was important.  An apparently excellent project might be of less value if it was prohibitively expensive. Leaky Wood Dams were usually a very cheap and effective option.


(26)     The Chairman replied to a question from Mr Bowles by saying that the presentations given to the Committee enabled its Members to disseminate the information in their Districts, Parishes and the wider community as well as within KCC itself. 


(27)      Mrs Brown said that the KALC Area Committees were always looking to invite speakers.  She could ask the KALC Chief Executive to promote these presentations to them. 


(28)     Mr Mackonochie said that he had been invited to inspect the work at the Alder Stream at Five Oak Green (see para 9).  The work being undertaken there had impressed him, particularly in his capacity as a Flood Warden.  This was certainly an example that KALC would find interesting.  His only concern was that the leaky wood dams wood need community involvement to keep them up to scratch. 


(29)     Mr Brown said that Kent Fire and Rescue would like the presenters to provide input on NFM as part of their training programme for Flood Managers on Module 5 Water Incident Management. He asked whether Volunteers were used to help build the flood management dams. 


(30)     Mr Cook replied that some of the dams were built by contractors as they involved specialist skills such as chainsawing.  The scheme at Bedgebury was mostly carried out by Volunteers.


(31)     Mr Rogers said that one of the most difficult tasks was the identification of land that could be used for NFM projects.  He was aware in his capacity as Chair of the Upper Medway Drainage Board that there were conflicting interests for farming landowners between their aim of maximising crop output and the protection of their land from flooding. 


(32)     RESOLVED that Mr Cook and Mr Williams be thanked for their presentations and that their content be noted.

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