This document is an output from the Devon and Cornwall Soils Alliance, delivered by Westcountry Rivers Trust.
Flood risk is a major issue for numerous communities across the South West and with the expected future impacts of climate change, as well as compounding factors such as population growth and development, it is a problem that is becoming all the more urgent. A number of projects are currently underway to understand the causes of flooding and investigate potential solutions. This includes the Upstream Thinking - Rapid Response Catchments project and Devon and CornwallSoils Alliance (more info on page 6).
A mapping exercise was carried out to identify all the micro catchments (5km2 or 10km2)above flood risk properties in Devon and Cornwall. The idea being that Natural Flood Management (NFM) measures and engagement with the local community weremost likely to be effective at this scale. These micro catchments were then prioritised according to a number of factors. The catchment described in this report, the catchment name, is one of those prioritised micro catchments.
The micro-catchment for Newton Poppleford’s Back Brook is 871.8ha and highlights 29 properties potentially at riskfrom surface water flooding, many of these are in Newton Poppleford. There are multiple possible contributing causes of this, including the topography and land use. The catchment is failing Water FrameworkDirective (WFD) regulations on ecological status and overlaps two Nitrate Vulnerable Zones (NVZs), two Ground Water Source Protection Zones (SPZs), and a Drinking Water Safeguard Zone at risk of contamination by nitrates. A rapid walkover survey wascarried out by an experienced surveyor from the Westcountry RiversTrust (WRT) to further inform potential issues and opportunities for flood riskmitigation. During the walkover, the micro catchment displayed localised flood risk.There is therefore opportunity to effect localised flood improvement although the ability to mitigate part of a larger flood riskdownstream (less localised) should not be discounted as further benefit. Additionally, the walkover presented opportunity to contribute towards WFD elemental improvement.
Implementation of Natural Flood Management (NFM) measures may have the potential to mitigate some of the flood risk and simultaneously make progress towards reaching “good” WFD status for the wider Lower Otter catchment that would ultimately benefit the local community. The NFM opportunities identified in this report include riparianwoodland planting and other habitat creation surrounding existing habitats across the catchment to slow surface water flow into watercourses and enhance habitat networks. More areas of land south of the A3052 entering into an agri environment scheme agreement could also contribute to improved soil health and biodiversity in the absence of significant habitats. There are opportunities for floodplain reconnection and runoff attenuation adjacent to the A3052 if carefully designed with stakeholders. Their proximity to the urban environment will need to be considered when designing these NFM measures, although this presents a major opportunity for community engagement to facilitate their delivery.
This documentisa study for causesof flooding,priorityconsiderations,and opportunitiesforNFMin the micro-catchmentforthe BackBrook, covering some of the Newton Poppleford urbanarea inEastDevon.
The study is builton multiple layersof mapped environmentalinformationand the results of the walkoversurvey. This informationhasbeenused to explore the current state of the catchmentand its environment, and then map areasfor further investigationand actionsto make improvements.
This micro-catchment scaleassessmentwillbe usedto guide efforts incommunityengagement andNFM.
The study has 5 key chapters,based on the current status of the micro catchmentand whatopportunitiesthere mightbe.
1. Micro-catchmentOverview
2. PriorityAreasand Drivers
• Flooding
• WaterQuality
• WaterQuantity
• Designated Sites
• Tourism and Recreation
3. Existing Natural Assetsand Their Condition
• Habitats
• Soils
• Crops
4. Issues
• Abstraction,Discharges,Pollution,and Runoff
• HydrologicalConnectivity
• Issues identified during Walkovers
5. Opportunities
• Existing Opportunities
• OpportunitiesIdentified during Walkovers
It isnot possible to map all aspectsof the status of the micro catchmentwithexisting datasets,and the true state of the catchmentmay not be fully reflected inthe datasetsforvariousreasons including the age of the data,the resolution, and the level of local knowledge takeninto consideration when the data has beencollected and mapped.
Assessing the qualityand conditionof natural assetsin particularischallenging due to the level of detail required.Nonetheless,the availabledata has beenreviewed and the bestdata currently availablehasbeenused. A full set of referencescan be found on pages36 38.
Flooding isa problem thatis experienced widelyacrossDevonand Cornwall,witha large portionof caseslinked to rivers(fluvial flooding as opposed to surface wateror sea).Riverwaterqualityisalso a key issue in the region,withall 381assessed rivers failing to achieve “good” statusin 2019.One importantreasonfor waterqualityfailure islinked to soil erosion.Soil erosioncan also contribute to increased fluvial flood riskdue to reduced channel capacitiesand blockages.Therefore,waterqualityand floodriskdriversare often interlinked and the solutionsto alleviate these pressures are often multifunctional.Two projectscurrentlyunderwayare aiming to tackle these issues by working withlocal communitiesto deliver small scale,land basedmeasures(“nature basedsolutions”).These projectsare Devonand Cornwall SoilsAlliance (DCSA) and Upstream Thinking
Afteritwas found that over 40%of soilsacrossDevonand Cornwall are degraded,the collaborativeprojectof the DCSA waslaunched inJune 2019. This aimsto build the capacityand capabilityinsoilsadvice forthe projectpartnersacrossthe 2 counties to work towards restoring degraded soils. One significantbenefitof improving soil healthisgreatersurface waterinfiltrationinto the ground before itreachesand overwhelmswatercourses, thereby reducing flood riskand preventing potential pollutantsfrom entering the water.Thisalso has the potential to make considerable Water FrameworkDirective (WFD) improvementsto waterquality.
AcrossDevonand Cornwall there are hundreds of Rapid Response Catchmentsthat are characterised byquicklydraining catchmentareasunder 10km2 (and under 5km2) , where during high rainfall eventssurface flowsand overland run off overwhelm small communities(1 50propertiesin flood zone 1).Flood eventshave increased inthese types of catchmentdue to degraded soilsthatno longerhave the infiltrationcapacity,simplified drainage patternsand more variable and extreme weatherpatternsassociated witha changing climate.UST RRCwill focusonworking withsmall communitiesinthese rapid response catchments to help them develop and delivertheirown climate resilience plansbyrestoring some of the hydrological functionalitywithinthe landscape.
The DCSA isworking in partnership with the UST RRCprojectacrossDevonto develop 24preparatoryinvestigationsonprioritised micro catchmentsto identifylikelyareasfornature based solutionsand NFM (Natural Flood Management) interventionswhere land ownership showsa willingnessand waterqualitycanbe improved.Communityengagementwill be criticalwhenimplementing NFMasmeasures need to be numerous and spread out across the catchmentto provide the greatestbenefits.If propertyowners and landownerscan work togetherand share perspectives, then measures canbe designed thatare agreeable to all stakeholdersinvolved.Thisalso helpsto fostera sense of community stewardship overtheir catchmentand NFM measuresthat would enhance theirlongevityand resilience.
OverviewThere may be opportunitieseverywhere forNFM measures and other nature-based solutionsatlow cost that also bring additional benefits to human health,biodiversity,and the aestheticsof the landscape. However,the scattered and fragmented locationsof propertiesat flood riskand the limited accessible fundsrequiresidentifying only the largestclustersof flood riskpropertieswiththe smallestupstream micro catchmentsto deliverthe mostimpactwiththe resources available.
The processof identifying priorityareasforopportunitiesto deliver improved waterqualityand quantityforclimate change resilience wasundertaken in four steps.
1. The South Westareasof Devonand Cornwall were modelled using GIS (Geographic InformationSystems) to identifywhere opportunityareaswere located.
2. The modelled opportunityareaswere ground-truthed in theory using desk based studies
3. The top prioritised opportunityareaswhere ground-truthed physicallyusing rapid walkoversurveys
4. Internal evidence reviews,external evidence reviews,and 2pagers summary documentswill be writtenfor24 trial investigationareas where physical interventionscan take place.
For more informationonthe first 3steps please see the appendix.
The final 24micro catchments,including the BackBrookwhichis shown in red.
Themicro-catchment was selectedin theGISmodelling step becauseit contains alarge numberof properties in NewtonPoppleford that are potentiallyat floodrisk.
The map below showswhichbuildingsoverlap withthe EA’s modelled “Flood Zone 2” area,specificallyareasatriskof flooding from rivers,as identified during the micro catchmentmapping process.
There are 29buildingspotentiallyatriskout of 123 in the catchment, approximately24%of them.
The catchment’ssize of 8.7km2 givesan area of 0.3km2 perbuilding at risk.
The waterframeworkdirective (WFD)statusinthe widerLowerRiver Otter catchmentis Poor.
If property ownersare willing to workwithland owners and vice versa, then small scale NFMmeasuresupstream in the catchmenthave the potential to benefita large numberof propertiesand improve water quality.
The micro catchment covers the urban areas of the towns of Newton Poppleford and Burrow, as well as several farms, and is intersected by the A3052 through the middle. The micro catchment forms the watershed for the Back Brook and its two main tributaries that flow northeast and southeast through Burrow and Newton Poppleford where it joins, as a tributary, the main River Otter. The total river length present in the catchment is approximately 17.8km. Overall, the micro catchment falls within the Newton Poppleford and Harpford County Parish and is administered by Newton Poppleford and Harpford Parish Council.
The map on the right shows the steepness of slopes. Back Brook is a confluence of two smaller unnamed streams, starting at the westernmost point of Burrow. These two streams lie at the bottom of shallow valleys that border a flat topped hill, Harpford Hill, in the centre of the catchment. These two streams converge in a flatter plain that continues until Back Brook exits the catchment. There are several more, smaller, flat topped hills in the catchment that border the streams. The town of Newton Poppleford is in the flattest partof the catchment.
The way the land is used has significant impacts on flood management. Land use has been mapped here using the Centre for Ecology and Hydrology’s (CEH) Land Cover Map 2019. This is a model derived from satellite imagery at 25m resolution.
The land use here is primarily arable and horticultural, accounting for 31% of the catchment, followed by the heather covering another 27%. Large areas of broadleaved and coniferous woodland border the heather in the western half of the catchment, making up another 25%. The rest of the catchment is made up from improved grassland and the urban areas. There is a single field of neutral grassland adjacent to the Back Brook on the western edge of the Burrow urban area.
It should be noted that this land cover map model is not a perfect representation of land use as it simplifies UK land cover into very broad classes.
Land use observed during the catchment walkover mostly matched the land use mapped here using the CEH Land Cover Map 2019.
There were conservation areas; an RSPB (Royal Society for the Protection of Birds) Aylesbeare Common Nature Reserve and a Clinton Devon Estates partneship Pebblebed Heaths Conservation Trust areas. These dominate the central upland Harpford Common heathland.
Harpford Common is surrounded by agriculture which was a mixture of beef, sheep and arable production. Some of the arable production noted on the map to the North of Newton Poppleford can be put to vegetables.
Copses of trees and woodland were interspersed throughout the catchment to the West of Newton Poppleford with some of the hedgerows now supporting corridors of mature trees.
The downstream rural valley sides next to the village were very oriented towards horse paddocks.
The base of Back Brook leaving Newton Poppleford and joining the main River Otter valley. This area is often flooded.
Flooding hasthe potential to negativelyaffectpeople and communities. Byconsidering boththe vulnerabilityof communitiesand the opportunitiesforland managementinterventions,actionscanbe targeted to have a positive impactoncommunitiesmostatrisk.
Flooding isone of a number of natural hazardswhichcan cause harm to people,the environmentand the economy.The primarydriverfor targeting thiscatchment isflooding.However,there are otherpriorityareasand driverswhich will be affected byNFMand candetermine the mostappropriate type of NFM forthe catchment. These are mapped inthe following pages.
The Neighbourhood Flood Vulnerability Index (NFVI) characterises vulnerability as communities likely to experience losses in wellbeing during flood events. This is based on their susceptibility, preparedness, responsiveness, and ability to recover, all without significant support from emergency services.
All of Newton Poppleford’s buildings are classed as “Relatively Low” in the Neighbourhood Flood Vulnerability Index (NFVI), meaning that they are slightly less vulnerable to losses in wellbeing from a flood event than the UK average. The catchment’s southwest corner overlaps with an area classed as “Very Low”.
The Social Flood Risk Index (SFRI) is a geographic measure of flood disadvantage. It identifies communities who are both exposed to flood risk by living on a flood plain and who are more vulnerable to the effects of flooding, due to factors such as health, preparedness and the availability of community support. Higher numbers of people living in a flood plain coinciding with high social vulnerability result in higher index values. The map highlights neighbourhoods identified as at riskof fluvial flooding higher than the national average. Please note that this is based on flood risk from rivers and the sea, so coastal areas may not be affected by changes in land management upstream.
At present, Newton Poppleford and its surrounding fields are classed as “Exposed” in the SFRI for river and coastal flooding, though the NFVI remains below the UK mean. This doesn’t increase in future projected scenarios of 2 and 4 degree temperature increases by the 2050s. The northern tributary upstream area of the catchment is classed as “Low” but this falls to “Exposed” but NFVI is still below the mean in future temperature increase scenarios.
When considering flooding, it is necessary to investigate records of previous flood events and combine this with modelled scenarios of what could happen, particularly in the face of the uncertainty of climate change affecting weather patterns.
The Back Brook has previously flooded in July 1968, July 1972, October 2008, March 2018, and February 2021 where channel capacity was exceeded. The March2018 flood resulted in lack of access to some local parks and the February 2021 flood caused evacuation of at least two residential properties. Six buildings fall within the recorded flood outlines. There are currently a bridge abutment, an embankment, and a series of linear natural high grounds that act as flood defences running approximately all the way from the catchment outlet to the confluence of the two upstream tributaries. These are not completely contiguous however. These are owned by a mix of private individuals and the local authority, were last inspected in May 2021, and are next due to be inspected in September 2022.
The EA’s modelled fluvial Flood Zone 2 dataset show areas predicted to flood from rivers in a storm event so severe it is likely to occur only once every 1000 years. This is also known as a 0.1% Annual Exceedance Probability. Flood Zone 2 was used to identify buildings potentially at flood risk as shown previously on page 8. Here, this covers the length of the Back Brook and extends nearly all the way up the northern tributary, as well as the full length of the southern tributary.
The EA’s Risk of Flooding from Surface Water (RoFSW) dataset shows the extent of flooding caused by rainwater flowing across the ground towards the nearestwater course in a 1 in 1000 year storm event. This overlaps frequently with Flood Zone 2, but also shows depressions in the ground where surface water will accumulate.
The modelled flood riskappears to be mostly accurate according to historic flood outlines and newer developments being built up from the Back Brook.
The village would appear to be at risk from large volumes of surface water as the valley, slopes, and impermeable surfaces such as roads are all fairly steep.
The Back Brook appears fairly marginalised and, in some places, channelised through Newton Poppleford although the extent of historic flooding wasn’t completely determined at the time of survey.
Surface water runoff and standing water was reported as a problem on the road network and could be a danger.
The Newton Poppleford & Harpford Parish Council meets on the last Monday of every month in the evenings at either Newton Poppleford Village Hall, the Pavilion or in Harpford Hall. The best contact is the parish clerk. The parish council have a neighbourhood plan which outlines measures to prevent future flooding (https://eastdevon.gov.uk/media/3720099/neighbourhood plan d51 final submission version.pdf) which is conveyed in the objective: protect and enhance the natural environment of the parish, and reduce vulnerability to impacts of climate change including minimising and managing flood risk.
The parish council has a community group on social media.
Clean and plentiful water is vital for a huge variety of our activities, and for supporting healthy ecosystems. Good water quality supports an efficient water supply, healthy natural habitats and cultural ecosystem services. A plentiful water supply is important for drinking water and household use, irrigation, industrial use and for maintaining habitats. Water quality is a key underpinning for the Water Framework Directive.
There are no Water Framework Directive monitoring sites in the catchment, but there is a very small priority wetland habitat in the form of a lowland fen just outside the catchment’s northern boundary. Another thin strip of lowland fen intersects the catchment boundary northwest of the Burrow urban area.
The catchment falls within the Mid Devon Nitrate Vulnerable Zone (NVZ) for Ground Water. The catchment is also adjacent to the Aylesbeare Stream NVZ for Surface Water in the northwest.
Much of the catchment, aside form the north and west, falls within a Ground Water Source Protection Zone III – Total Catchment area and there are Zone II Outer Protection Zones on the southeastern boundary. Furthermore, there is a Drinking Water Safeguard Zone for Ground Water in the eastern half of the catchment, identified as being at risk of failing the drinking water protection objectives due to contamination by Nitrates.
It is also important to note that there is a historic landfill site called Aylesbeare Quarry eastof Mount Pleasant just north of the A3052 For more information on water quality go to slide 29.
The amount of water available for abstraction is an indicator of how much drinking water is available for people. The catchment sits within an area not currently available for licensed water abstraction (left map) but is bordered to the west by areas where water is available for licensed abstraction.
In the context of NFM, it is also necessary to consider water availability for plants and wildlife. Drought can cause vegetation to die back, leaving bare soil exposed and more vulnerable to erosion and runoff when it eventually rains. The Vegetation Health Index (VHI) uses satellite data to combine temperature and vegetation condition to characterise vegetation health. Areas are scored between 0 and 1 with lower values indicating low drought risk to plant health and higher values indicating higher risk. The north of the catchment is scored low at 0.335 on the VHI (right map), indicating low risk to plant life from drought stress, while the central and southern areas score higher at 0.449, indicating relatively higher riskbut remains below the UK mean.
Designated habitat sites, from small local nature reserves all the way up to large national parks, need to be protected for the wealth of benefits they provide to people and the environment, including already providing some degree of NFM. A site being designated can be an indicator of habitat health.
Nearly all the catchment falls within the East Devon Area of Outstanding Natural Beauty (AONB).
Much of the catchment is designated as Sites of Special Scientific Interest (SSSI) and Special Areas of Conservation (SAC).The collective name for these sites is East Devon Pebblebed Heaths. The largest SSSI/SAC site in the north of the catchment is also an RSPB reserve, known as RSPB Aylesbeare Common.
There are some areas in the west of the catchment that fall outside of any designation.
Clean air is important for people’s health and for healthy ecosystems. Air quality is the term used to describe the levels of pollution in the air. When air quality is poor, pollutants in the air may be hazardous to people, particularly those with lung or heart conditions. In the past, the main air pollution problem was smoke and sulphur dioxide from fossil fuels such as coal. Now, the major threat to clean air is from traffic emissions. Petrol and diesel motor vehicles emit a variety of pollutants, principally carbon monoxide (CO), oxides of nitrogen (NOx), volatile organic compounds (VOCs) and particulate matter (PMx).
A growing body of researchsuggested that smaller particles, in particular PM less than 2.5μm in diameter (PM2.5), is a metric for air pollution which is closely associated with the adverse health effects of poor air quality. Therefore, this section will use data relating to PM2.5 where relevant.
Improvements to the soil and surrounding environment have the potential to also deliver improvements to air quality through natural filtering processes.
The central Burrow and Newton Poppleford areas have a relatively low concentration of air particulate matter of 6.97PM2.5 from emissions. The highest concentration of 7.11PM2.5 is found in the centre of the catchment, west of the urban areas on the A3052 road. The restof the catchment is also relatively low in air particulate concentrations, with the lowest recorded at 6.64PM2.5 in the south.
Areas and features important for tourism and recreation may also be at flood risk and it is necessary to protect them for a healthy society and environment.
There are two greenspaces within Newton Poppleford, one is a cemetery, the other an allotment plot.
The main tourism feature of the catchment is the RSPB Aylesbeare Common area of the East Devon Pebblebed Heaths SSSI and SAC, with its neighbouring non RSPB sites a close second. These areas are also Countryside Right of Way (CRoW) Access Land and Registered Common Land.
A series of Public Rights of Way (PRoW) go through these areas. The most notable PRoW path runs from the west border of the catchment down to just north of Burrow, crossing through the RSPB reserve/SSSI/SAC. Two PRoWs also run between Newton Poppleford and Burrow connecting the two urban areas.
Biodiversity,the varietyof life of earth,is valuable initsown right. Italso supports recreation,food,flood protection and climateregulation. This sectionwill predominantlyexplore whathabitatsand othernatural assetsare presentin the catchmentthat will already be contributing to NFM and could be improved withfurther NFM measures.Water, soilsand crops are natural assets in themselvesand will also be investigated.
The natural assets mapped below are habitats which have the potential to support thriving plants and wildlife. Thriving vegetation is very valuable for NFM as it roughens the ground, thereby slowing down surface water flow, meaning water courses are less likely to be overwhelmed in a storm. In addition, plant roots provide structural support for the soil and prevent surface water washing soil into water courses.
Where the assets are present the landscape is likely to be contributing to the provision of habitats, biodiversity and even NFM. Where assets are absent there may be a lack of habitats which contribute to or support thriving plants and wildlife. Assets may still be present however in the form of crops and soils which are mapped in the following pages.
Multiple patches of broadleaved woodland are scattered about the catchment, particularly in the land parcels to the north and west surrounding the heathlands. Much of these are deciduous woodland priority habitats. Coniferous woodlands also feature in the west and southwest, with other smaller patches in the north and centre.
There is a small traditional orchard in the northwest, another on the southwestern catchment boundary, and a third immediately north of Newton Poppleford and just outside of the boundary.
The habitat that covers the most area in the catchment is lowland heathland, corresponding with the East Devon Pebblebed Heaths SSSI and SAC. The SSSI in the north, covering the largest continuous area (and the RSPB reserve), has been assessed as in Favourable condition. The two sites south of this are both in Unfavourable Recovering condition, and the site in the very north, mainly outside of the catchment is in Unfavourable No Change condition.
It is important to determine the current condition of water quality. Poor water quality can be detrimental to people, wildlife, and may cause other negative effects during a flood event. Good water quality should always be protected. A key set of evidence used to assess the water quality in a catchment is the Water Framework Directive (WFD). The status of a waterbody is measured using a series of parameters and is recorded on the scale: high; good; moderate; poor; bad (with moderate and worse being regarded as a failure).
The micro catchment sits within the larger Lower River Otter WFD river waterbody catchment, accounting for 11% of its area.
The Lower River Otter is overall classed as Poor meaning it is failing WFD regulations. It is currently failing on several categories. In 2019, 100% of waterbodies in the UK failed on chemical status after the EA included monitoring “mercury and its compounds” and “Polybrominated diphenyl ethers (PBDE)” into its water quality monitoring methodology.
The Lower River Otter has been classed as Moderate for Fish, and Poor for Phosphate, Macrophytes, and Phytobenthos. It is classed as “does not supportgood” for its Hydrological Regime, but is classed as Good or High for other ecological elements. Nevertheless, the overall ecological status is Poor and therefore failing WFD regulations on ecological grounds.
It is failing for phosphate due to poor livestock management and ground water abstraction by South West Water. It is failing for Macrophytes and Phytobenthos because of poor livestock and soil management, and sewage discharge and ground water abstraction by South West Water. No reason is currently given for why it is failing on Fish.
The waterbody is classed as Good for nearly all chemical classifications, except for mercury and its compounds, and PBDEs, where it is classed as Failing. It is also Failing for Perfluorooctane sulphonate (PFOS). The waterbody’s overall chemical status is consequently Failing and is therefore failing WFD regulations on chemical grounds as well as ecological.
The are over 60 metrics that the EA can use to monitor waterbody catchment statuses. For more information and a breakdown of this catchment’s status go to link.
Crops can be a natural assetin themselves, providing the food we eat and storing carbon. Some crops however, could be considered natural liabilities. One such crop is maize which is planted in wide rows, leaving bare soil exposed and without structural supportfrom roots. Furthermore, it is often harvested in late Autumn when the weather becomes wetter, meaning little to no vegetation can regrow to protect it over Winter. This leaves the soil much more susceptible to being carried away by surface water runoff. Despite this, maize can be successfully managed to grow and harvest while minimising runoff.
The Crop Map of England (CROME) dataset is derived from satellite data and generalised to hexagons. It identifies the villages of Newton Poppleford and Burrow as non vegetated with the majority of the catchment classed as grassland, and various scattered clusters of trees. Some maize, spring barley, and spring wheat are grown in the east.
The nature of the soil can determine how much surface water infiltrates into the ground, as well as what plants will growand where. Understanding soils is vital to providing effective NFM and improving water quality. The aim with water quality improvements is to keep the soil on the land and improve groundwater infiltration and recharge, therefore allowing a slower and more naturally filtered water route to the river.
Degraded soil structure, where the soil profile is compacted at shallow depths or capped at the surface and impermeable can lead to excessive unnatural run off of surface water instead of percolation and infiltration. More than 60% of soils in Devon and Cornwall are naturally well drained and should rarely become saturated.
The Farming Rules for Water (FRFW) were introduced at the start of 2018 as legislation to help protect surface water quality. The regulations are designed to help manage cultivated agricultural land well, without over management, nutrient run off, or waste affecting surface water.
The diagram above shows good soil structure on the left and compacted soil structure on the right. In compacted soil, little surface water can infiltrate into the soil subsoil due to surface capping or compacted layers, while vegetation can be deprived of oxygen due to compression of pores that normally transport air and water (sourced from SEPA NFM Handbook).
The NATMAP soils dataset from Cranfield University shows that the catchment is primarily composed of the soil series Bromsgrove in the eastern half of the catchment, followed by a mix of Brockhurst and Goldstone in the west. The soil series Conway is present at Newton Poppleford at the catchment outlet. There is also an area of Whimple 3 on the catchment boundary in the west.
At the time of the walkover survey, soil health in the catchment was considered good in some places and adequate, or possibly poor, in others through general observation and further investigation would be needed to conclusively determine the soil status.
Compaction wasn’t determined at the time of survey but could be considered when looking at soil health to help the overall productivity and function.
Geological conditions impacts groundwater and soil type. When rocks are sufficiently permeable it can lead to groundwater flooding. If local flooding is caused be groundwater levels then it is unlikely that changes to land management and NFM will improve flood resilience.
According to the British Geological Survey, the east of the catchment is predominantly sandstone with areas of colluvium and river terrace sand/gravel interspersed. The west of the catchment is composed of a mix of conglomerate, colluvium, claystone, and mudstone.
The Back Brook itself and its two main tributaries have underlying riverine clay and floodplain sands and gravel.
The walkover didn’t uncover any initial suspicion of groundwater flooding and the perception is that any flood risk would originate from surface flow.
Multiple issues have already been mentioned and mapped that could be contributing to flood risk and WFD failures. However, there are further potential issues that may be influential which will be explored in the following pages.
Pollution incidences themselves will directly affect water quality, but consented discharges into watercourses and chemical runoff from roads exacerbated by rainwater may also be sources of pollution.
There is one recorded pollution incident in the catchment in the northwest. This was caused by diesel in April 2007 and was classed as a Category 1 Major water pollution incident, the most severe possible. It was also classed as Category 2 Significant to land pollution and and Category 3 Minor to air pollution.
Three sources of consented discharges are present in the catchment. The site in the southwest is for a domestic property discharging treated effluent into ground water via a soakaway. The site in the north west by Mount Pleasant is for a restaurant also discharging treated effluent into ground water via a soakaway. The third site is in Newton Poppleford belonging to SWW for a storm tank discharging storm sewage overflow into the Back Brook.
There are two further consented discharge sites just outside of the catchment boundary in the east and west. Both are for farms discharging treated effluent into soakaways.
Licensed water abstraction points may serve as sources of risk to ground water quantity and availability. There is one located in the centre of the catchment adjacent to the A3052 for agricultural use for direct spray irrigation.
Surface flow pathways are the routes rainwater accumulates and follows when it lands to the nearest depression or watercourse. As it flows, surface water can pick up any number of chemicals, soil, and debris and carry them into the watercourse with it. This serves to demonstrate why community engagement and working with land owners is so important, as the effects of practices upstream in the catchment cascade down via these routes. Pathways have been modelled in 2 different ways here.
The first are modelled using topographic data and software called SCIMAP (left). Only the routes with above average wetness are shown. The flat topography of floodplains skews the modelling process and the pathways in these areas should be considered unreliable.
The second method uses SCALGO Live (right). Flow routes with at least 1km2 upstream area are shown. Areas that would be flooded if 15cm of rain were to fall during a storm event are also mapped. Flooded areas are coloured by their water volume from light to dark.
During the walkover surveys, experienced surveyors at WRT recorded points of interest and concern, as well as potential natural flood management opportunities. The results are mapped (right) but it should be noted that the map is by no means exhaustive.
The river through Newton Poppleford appeared to be heavily incised in places and disconnected from the floodplain.
The waterway had been marginalised and channelised in places which forces water to take one restricted pathway.
When this route is overwhelmed by water volume, there is risk of the water topping out in places and causing flooding.
Depending on the time of year, bare soil or exposed soil during seasons of high rainfall can be high riskto water quality and flooding with no vegetation to slow the surface water.
This map of issues was generated after one walkover survey, reflecting the situation at the time of survey. It is not exhaustive and doesn’t reflect all issues present in the catchment which will take much more effort to determine. A greater range of all the issues is present within the previous section. Any projects delivering in the catchment should undertake their own walkovers for confirmation and addition to the list.
There are many options to reduce flood and coastal erosion risk across the country which involve implementing measures that help to protect, restore and emulate the natural functions. These options are known as Working With Natural Processes (WWNP) or Natural Flood Management (NFM). These measures increase flood resilience by slowing the flow of water and disperse energy to keep the water at the top of the catchment or to improve groundwater infiltration and recharge, therefore allowing a slower and more naturally filtered water route to the river.
Where rapid surface water run off has been noted there may be opportunities for WWNP to mitigate both water quality and to regulate flow. An example of some NFM interventions are given below. They are intended to slow water, store water, increase infiltration and intercept rainfall.
The illustration above shows various natural flood management techniques (sourced from CIRIA).
The Environment Agency have mapped potential opportunities for WWNP to reduce flood and coastal erosion risk across the country. These include opportunities for different types of woodland planting, floodplain reconnection features like restored riverside wetlands and meadows, and runoff attenuation features which aim to slow pathways of water across the land, like storage ponds or leaky barriers. Anumber of areas are also excluded from the woodland maps such as urban areas and existing woodland. These are mapped separately on page 40.
The greatest opportunity identified by these WWNP datasets for the catchment is construction of smaller scale runoff attenuation features in or near the streams that are strategically placed to slow the flow of surface water before it reaches the water course, allowing excess water to dissipate rather than flood during a storm event. These opportunities are most concentrated in the southwest and north of the catchment, with some on the central heathlands.
There are also opportunities for riparian tree planting along the small streams further up the catchment before they converge to form the Back Brook. Much of this could be combined with floodplain woodland planting. Furthermore, it may be possible to reconnect some small areas of floodplains upstream in the catchment along the two main tributaries.
There may be current habitat creation and river restoration projects where opportunities exist to work together with organisations to provide simultaneous benefits to habitats, rivers, and flood resilience.
Natural England have also identified opportunities to expand on existing habitats to create habitat networks across the landscape.
Habitat restoration and creation is knownto occurin some small areas in the north of the catchmentunder agri environmentschemes explored on the next page.
There are significantopportunities for expanding habitat networks around existing priority habitats (see page 24).
Some small areas in the south and southwest have been identified as Restorable Habitat defined as “Areas of land,predominantly composed of existing semi natural habitat where the primary habitat is present in a degraded or fragmented form,and whichare likely to be suitable for restoration.”
There are Fragmentation ActionZones in the north of the catchmentsurrounding some of the heathland. Natural England defines these as “Landimmediately adjoining existing habitat patches that are small or have excessive edge to area ratio where habitat creation is likely to help reduce the effects of habitat fragmentation.”
Most of the area surrounding the SSSI and SAC areas in the catchmentare Network EnhancementZone 1, defined as “Land withinclose proximity to the existing habitat componentsthat are more likely to be suitable for habitat re creation for the particular habitat. These areas are primarilybased on soils but in manycases has been refined by also using other data such as hydrology,altitude and proximity to the coast.”
In the agriculturalareas southwest of and surrounding the urban areas are the Network Expansion Zones, defined as “Land withinrelatively close proximity to the Network Enhancement Zones that are more likely to be suitable for habitat creation for the particular habitat and identifying possible locationsfor connectingand linkingup networks across a landscape.”
Very limited patches inbetween the other zones are classed as Network EnhancementZone 2, “Land withinclose proximity to the existing habitat componentsthat are unlikelyto be suitable for habitat re creation but where other types of habitat may be created or land management maybe enhanced including delivery of suitable Green Infrastructure.”
Agri environment schemes are government initiatives that aim to financially compensate farmers for providing benefits to wildlife on their land. Areas under agri environment scheme agreements may provide opportunities simultaneously for the landowner to meet the agreement’s objectives and deliver NFM to benefit the catchment community.
Some of the land parcels bordering the SSSI and SACs in the centre and north of the catchment are under Environmental Stewardship Scheme Agreements.
There are opportunities for landowners in the rest of the catchment to enter into agri environment schemes. Habitat creation in the east of the catchment in the Network Enhancement and Expansion Zones may be facilitated if landowners were to enter into an agri environment scheme.
A further consideration for the targeting of NFM via soil improvement,habitat enhancements,restoration or creation is existing areas whichmaynot be suitable for changes in land use or land management.This maybe because they are already valuable sites for wildlife (e.g.designated wildlife sites), because the land use is difficultto change (e.g. urban land) or because the land is highly valuable for farming(high grade agricultural land).There may be further historic or natural heritage designations to consider.
The SSSI designations (see page 20) covering most of the central catchmentmay provide administrative challenges, as will the deciduous woodland and traditional orchard priority habitats. However, there is still the opportunity to improve these habitats and designated sites further by getting more partner organisations involvedin the process and even access additional sources of funding.
The WWNP woodland constraints dataset highlights any urban areas and existing woodlands (includingwoodlandsnot listed as priority habitats not shownhere) where additional tree planting maybe difficult.Thisexcludes muchof the urban areas. Thisdoes not mean urban tree planting is impossible, and would also provide another avenue to get the communityinvolvedthecloser the planting is. The southeastern areas of the catchmenton the other hand have few to no constraints.
The agriculturalland grade is considered grade 4, whichis poor, or ungraded non agricultural land in the protected heathland areas. The land surrounding these in the west of the catchmentis grade 3 whichis considered average. The farmland in the east is considered grade 3 immediatelysurrounding Burrow and Newton Poppleford, grade 2 (considered good) adjacent to the heathland, and grade 1 (considered very good) on the northeastern and southeastern boundaries. Changingthe land use from farming to other habitat creation in these grade 2 and 1 areas may prove difficultwith suchhigh quality agricultural land. However,there is no high grade land in the west of the catchment.
There are two scheduled monumentspresent. One is in the form of two bowl barrows on the RSPB reserve immediatelynorth of the A3052. The other is a bowl barrow on the heathland by the northern boundary.
During the walkover surveys, experienced surveyors at WRT identified opportunities for NFM measures and improvements to other key considerations mentioned. The results are mapped (right) but it should be noted that the map is by no means exhaustive.
Dry crested barrier in stream next to road and bridge.
May be opportunity to remove barrier and reduce the backing up effect with ability to affect the road network or other downstream consequences.
Upper catchment road drainage ditch and old hedge line in field.
May be opportunity by agreement with respective landowners to blind ditch the road drainage and take the water back to the fields or attenuation features.
May also be the possibility of restoring old hedge lines across contours to attenuate or interrupt overland flow.
This map of opportunities was generated after one walkover survey, reflecting the situation at the time of survey. It is not exhaustive and doesn’t reflect all opportunities present in the catchment which will take much more effort to determine. A greater range of all the opportunities is present within the following section. Engagement with landowners and stakeholders is required for a more comprehensive list of opportunities and ascertain if suggestions can be implemented in conjunction with current land use, future land use and business plans.
It
also be
farm
an important way of
water to improve flood resilience and to form a buffer for water quality. Ponds provide settlement
bioremediation for water quality if designed
the
and promoting a slower release
or into groundwater, is more desirable for future flood resilience and could add value to a climate
response for local and downstream beneficiaries.
opportunity and willingness in the catchment for this type of intervention.
are some opportunities to improve flood resilience in the Newton Poppleford Back Brook through increasing channel and floodplain roughness to slow the
catchment is quite steep in places where it comes of the heathland so interventions in the steepest areas will be of limited value, but the key to slowing the flow is likely to be multiple features working in sequence and synchronicity to hold back pockets of water in less steep areas.
Large woody debris, leaky barriers, or floodplain reconnection could be a good opportunity in the rural area if it fits with the land manager’s business model and has complementary topography.
some areas the river is too “squeezed” and marginalised to allow channel restoration in between built infrastructure.
There are 27 landowners in the catchment. The 3 largest landowners own 29.89% of the catchment. WRT has engaged with farmers managing 51.15% of the total farm area under UST.
There is no evidence of a community climate group in Newton Poppleford or Burrow, other than the already identified parish council community group.
As well as the opportunities identified in the previous section, there may be opportunities for you to get involved as an individual.
WRT runs a Citizen Science Investigation (CSI) team of volunteers across the south west, whereby volunteers receive a testing kit and training to procure water samples from a watercourse. Westcountry CSI aims to engage people with their local environment, and produce water monitoring data that can identify pollution events quickly and target improvement work.
There is an active CSI sampling site just outside of the catchment on the Back Brook. There may be the potential for more sampling sites along the main Back Brook stream in Burrow or Newton Poppleford and further up the catchment if there is suitable access to the water.
For more information about Westcountry CSI, including instructions on what’s involved and how to sign up, visit our website at wrt.org.uk/westcountry csi
Another opportunity for you to get involved in is the Riverfly Partnership’s Anglers’ Riverfly Monitoring Initiative (ARMI). This recognises that anglers are very well placed to monitor river water quality and facilitates communication between them and their local Environment Agency contact.
There are no riverfly survey sites within the micro catchment, but, as with CSI sites, it may be possible to start a new site if there is suitable access to the water and with communication with the Environment Agency.
For more information on ARMI, visit their website at riverflies.org/anglers riverfly monitoring initiative armi
Multiple reasonsforthe possible causesand remediesforflooding inthe micro catchmentforthe NewtonPoppleford BackBrookhave been mapped inthis study, as have other factorsthat are key to considerwhen making NFM decisions.
It islikelythat a combinationof causesare at playhere contributing to there being propertiesatflood risk,including the topographyand land use.
It has beenestablished thatthere iswaterqualityissues through WFD failuresand problemswithsurface waterflooding,althoughthe full extent of flooding will need furtherinvestigationto ensure the effortof reductionis proportional. Ithasalso beenconfirmed thata solutionexistswithin the community,through a willingnessfrom the rural communityto make adjustmentsto the waythe land is managed providing the proposals allow beneficial integrationwiththe land manager’sbusinessmodel.
The nextsteps are to confirm how many propertiesinNewton Poppleford are definitelyimpacted,oratriskof impactinmore extreme weather, and to engage and empowerthe communityin the catchmentto discuss and work towardsbuilding flood resiliencethroughsome of the opportunitiesmapped inthe previouspages.It isimperative thatpropertyownersand landownersshare perspectivesand work togetherto find solutionsagreeable to all sides.Some opportunitieswillprovidesecondarybenefitstowardsimproving the catchment’sWFD ecologicalstatus.
The processforidentifying the highest impacting locationsof NFMmeasures acrossDevonand Cornwall involved several stepsin a Geographic InformationSystem (GIS).The first step was to identifywatercourseswithan upstream watershed less than 10km2 and less than 5km2 in size,then to identifypropertiesadjacentto these watercoursesthat overlapped withthe EnvironmentAgency’s (EA) fluvial “Flood Zone 2”dataset.Next,pour pointswere placed onthe watercoursesin front of the furthest downstream flood riskproperties.These pourpoints were thenused to delineate the upstream micro catchmentboundaries.A total of 1270micro catchmentswithpropertiespotentiallyatriskwere identified across the 2counties.
For every micro catchmentidentified,itsarea wasdividedbythe number of flood risk propertieswithinitto calculate the area perproperty atrisk foreach micro catchment.Those withthe lowestarea perpropertyindicated higherpotential forsmall scaleNFMmeasuresto benefitthe greatest number of flood riskproperties.
Lastly,additional factors,suchas WFD classificationsand previousWRT engagementwithfarmers,were considered alongsidethe area perproperty atflood risk toprioritise a small numberof micro-catchmentsto targetcommunityengagementand NFM delivery.
➢
Due to the large geographic extent(Devonand Cornwall)and the manual elementof the mapping (bothcausing the mapping processto be time consuming),the resolution/accuracyof some datasetsmaybe compromised.
➢ The buildingsdataset(OS VectorMap Buildings) isnotasaccurate as OS MasterMap some propertiesare amalgamatedinto a single polygon and very small buildingsare notshown. Therefore propertiesatriskof flooding maybe underestimated.
➢ Potential flood riskisidentifiedbyselecting building polygonsthatintersectthe flood zones;no detailed local information (e.g.drainage or defences) ormodelling hasbeenused.
➢
The spatial resolutionof the topographydata iscoarse (50m).Thisisused to calculate the upstream catchmentarea foreach communityat-risk. Therefore,some errors mayoccur (additionsoromissions) whenidentifying micro-catchments.
➢ The mapping method involvesanelementof manual validation,whichhasthe potential to be subjective and/orpossible errors.
Once catchmentswere modelled and the informationtabulated to show theoretical flood risk in conjunctionwithWFD failures, a systematic approach to ground truthing was adopted.
Catchmentsthat were perceived to have elevated water quality and water quantity risks were discussed with local land management advisors and regulators to determine if the modelled risk was likely to be correct.
Upon a theoretical, or desk based ground truthing,the catchmentswere then surveyed using a rapid walkover survey to observe run off pathways and confirm if useful managed interventions could be implemented to reduce flood risk locallyand improvewater quality in the process.
A further modelling process using SCIMAP was undertaken to identify high risk run off pathways of the specific micro catchmentbeingsurveyed to assist the surveyor in locating issues within a <10km2 area.
Where possible, surveyors reacted to high rainfall predictions and went out to observe the catchmentwhen the conditions were right.
Walkover surveys were undertaken noting observations about surface water run offand taking photographs of key areas and issues. All walkovers aimed to provide:
Dry or Wet weather photos,
Identify stakeholder PROVIDERS where NFM can be instigated,
Identify stakeholder BENEFICIARIES by property and number people,
Establish opportunities in each catchmentand feasibility of action.
Georeferenced photos were taken to provide a visualoverview of issues, opportunities, and as general reference notes.
Where issues and opportunities existed, further investigation was made or attempted to establish the realistic chances of further action. This was achieved by either speaking withthe localcommunityor contacting communitygroupsor key landowners.
All 1270 micro catchments with properties potentially at risk were identified across the 2 counties.
CIRIA (Slide 43)
The Construction Industry Research and Information Association’s (CIRIA) Natural Flood Management Manual (C802) (PDF)
FRFW (Slide 32)
Statutory guidance for Farming Rules for Water (FRFW) (Webpages)
https://www.ciria.org/Books/Free_publications/C802F.aspx
https://www.gov.uk/government/publications/applying the farming-rules-for-water/applying-the-farming-rules-for-water
SEPA NFM Handbook (Slide 32)
Handbook describing various natural flood management interventions and case studies (PDF)
https://www.sepa.org.uk/media/163560/sepa-natural-floodmanagement-handbook1.pdf
Dataset Source AttributionStatement
Agricultural Land Classification Natural England © Natural England copyright. Contains Ordnance Survey data © Crowncopyright anddatabase right2022.
Air Quality Management Areas UKAIR
© Crown copyright and database rights licensed under Defra's PublicSectorMapping Agreementwith Ordnance Survey(licence No. 100022861) and the Land andProperty Services Department(Northern Ireland) MOU206.
Ancient Woodland Natural England © Natural England copyright. Contains Ordnance Survey data © Crowncopyright anddatabase right2022.
AONB Natural England © Natural England copyright. Contains Ordnance Survey data © Crowncopyright anddatabase right2022.
Areas Benefitting fromFlood Defences EnvironmentAgency
© EnvironmentAgency copyrightand/or database right 2018. Allrights reserved.Some features of this mapare based on digital spatial data from the Centre for Ecology & Hydrology,© NERC (CEH) © Crowncopyright anddatabase rights 2018Ordnance Survey 100024198
Bathing Water Monitoring Locations EnvironmentAgency © EnvironmentAgency copyrightand/or database right 2015. All rights reserved.
Country Parks NaturalEngland © Natural England copyright. Contains Ordnance Survey data © Crowncopyright anddatabase right2022.
Countryside StewardshipScheme Agreements
Natural England © Natural England copyright. Contains Ordnance Survey data © Crowncopyright anddatabase right2022.
Crop Map of England Rural Payments Agency © Rural Payments Agency
CRoW Access Land NaturalEngland © Natural England copyright. Contains Ordnance Survey data © Crowncopyright anddatabase right2022.
CRoW RegisteredCommonLand NaturalEngland © Natural England copyright. Contains Ordnance Survey data © Crowncopyright anddatabase right2022.
DetailedRiver Network EnvironmentAgency © EnvironmentAgency Crown copyrightand databse right 2022.
Drinking Water Safeguard Zones (Ground Water)
EnvironmentAgency © EnvironmentAgency and/ordatabase rights. Derivedfrom BGSdigital data under licence from British Geological Surveycopyright NERC.
Drinking Water Safeguard Zones (Surface Water) EnvironmentAgency
© EnvironmentAgency copyrightand/or database right.All rights reserved. Derived fromBGS digitaldata underlicence fromBritish Geological Survey ©NERC. Derived fromCentre
Flood
Flood
Historic
by
in part from data
SPAs