Easton Broad Flood Management Project

Transcription

1 Easton Broad Flood Management Project Final - 27 July 2012 Title here in 8pt Arial (change text colour to black) i

2 We are the Environment Agency. We protect and improve the environment and make it a better place for people and wildlife. We operate at the place where environmental change has its greatest impact on people s lives. We reduce the risks to people and properties from flooding; make sure there is enough water for people and wildlife; protect and improve air, land and water quality and apply the environmental standards within which industry can operate. Acting to reduce climate change and helping people and wildlife adapt to its consequences are at the heart of all that we do. We cannot do this alone. We work closely with a wide range of partners including government, business, local authorities, other agencies, civil society groups and the communities we serve. Published by: Environment Agency Horizon house, Deanery Road Bristol BS1 5AH enquiries@environmentagency.gov.uk Environment Agency 2011 All rights reserved. This document may be reproduced with prior permission of the Environment Agency. Further copies of this report are available from our publications catalogue: Hhttp://publications.environmentagency.gov.ukH or our National Customer Contact Centre: T: Henquiries@environmentagency.gov.ukH. Easton Broad Flood Management Project

3 Contents 1 Introduction 1 2 Why is the proposed development required? 2 3 Alternatives 3 4 What is the existing environment at the proposed development site? 4 5 What does the proposed development comprise? 6 6 Consultation 8 7 What does the Environmental Impact Assessment Process involve? 9 8 What are the predicted likely significant effects of the proposed development? Recreation Biodiversity Landscape and visual effects Water resources and flooding Historic environment Cumulative and in-combination effects 17 9 Conclusions Where can more information be found? 20 Figure NTS 1 Figure NTS 2 Figure NTS 3 Figure NTS 4 Figure NTS 5 Figure NTS 6 Site Location Plan Existing Situation Site Boundary Statutory Designations Proposed Embankment Alignment and Construction Phases Preliminary Water Control Strucure Proposals Easton Broad Flood Management Project i

4 ii Easton Broad Flood Management Project

5 1 Introduction The Environment Agency is applying for planning consent for construction of an earth embankment and culvert improvements at Potter s Bridge, Easton Broad, Suffolk. These works comprise the Easton Broad Flood Management Project (FMP). Potter s Bridge and Easton Broad The planning application for this proposed development is accompanied by an Environmental Statement, as required under The Town and Country Planning (Environmental Impact Assessment) Regulations 2011 (SI 1824) (the EIA Regulations ). The preparation of this Environmental Statement forms part of the Environmental Impact Assessment (EIA) for the proposed development. This report is the non-technical summary of the Environmental Statement, and is provided both as a standalone report and at the beginning of the Environmental Statement. It summarises the content and conclusions of the Environmental Statement, to which readers should refer if more detailed information is required. The following sections of the non-technical summary describe: the reasons why the proposed development is required; the existing environmental conditions at the proposed development site; what the proposed development comprises; the EIA process; the likely significant effects of the proposed development; and the next steps and where the Environmental Statement can be viewed. Easton Broad Flood Management Project 1

6 2 Why is the proposed development required? The Easton River Valley, including Easton Broad which lies at the seaward end of the valley, supports the second largest freshwater reedbed in the United Kingdom, totalling 180 hectares. This reedbed lies within the Benacre to Easton Bavents Special Protection Area (SPA), a wildlife site of European importance, designated for its breeding and over wintering bittern and marsh harrier. Additionally, Easton Broad to the east of Potter s Bridge, is part of the Benacre to Easton Bavents Lagoons Special Area of Conservation (SAC) designated for its saline lagoon habitat. The freshwater reedbed is at risk from the ingress of sea water and the landward movement of the shingle ridge and saline lagoon as a result of a dynamic coastline and the cessation of management of the shingle ridge in The management of the shingle ridge was stopped based on Natural England s advice that the mechanical management of the shingle ridge was not consistent with the conservation objectives for the saline lagoon (SAC designated) and the on-going management practice of the frontage was not sustainable. Shingle ridge and coastal lagoon Under European legislation, there is a duty to take appropriate steps to prevent the deterioration of SPAs and SACs (collectively known as European sites). The purpose of the Easton Broad Flood Management Project is to protect as much of the Easton Valley reedbed as possible from deterioration. In addition, the scheme allows for sufficient time to identify and secure compensatory habitat in relation to the Suffolk Shoreline Management Plan 2 (SMP2) at a more sustainable site in advance of loss. 2 Easton Broad Flood Management Project

7 3 Alternatives The following options were identified and appraised for Easton Broad: Option 1 - Do nothing. Option 2 - Do minimum. No works on site but provide compensation measures as part of the Suffolk SMP2 to ensure compliance with European legislation; Option 3 - Do minimum (maintain). This option would involve repairing breaches in the shingle ridge after they have occurred. Option 4 - Reinstate beach maintenance (sustain). This option would involve raising the height of the shingle ridge to pre-2006 levels, and maintaining it at that level. Option 5 - Hold the line with hard defence (improve). This option would involve the construction of a hard defence, or combination of hard defences, such as rock groynes, breakwaters or revetments, to prevent roll back of the shingle ridge. Option 6 - Hold the line with soft defence (improve). This option would involve placing large quantities of marine dredged shingle along the shore to help replace that lost and to replace and maintain the shingle ridge. Option 7 - Managed realignment with secondary defence (improve). This option would accept the natural roll back of the shingle ridge over time and allow it to behave naturally whilst constructing a secondary (set-back) line of defence. All possible coastal defence options were assessed against a range of criteria, especially: Technical feasibility; Cost (both capital and maintenance); Maintaining favourable condition of European qualifying features; and Working with, rather than against, coastal processes. An initial assessment concluded that Option 2: Do minimum was the preferred option on the grounds of costs. However, during the development of the Suffolk SMP2 it was concluded that simply recreating the habitat elsewhere (Option 2) may be in breach of European legislation, and the Environment Agency should try to protect as much as of the European habitat as realistically possible in situ. Hence, the original Option 7 is now considered to be the preferred option, and this option is the subject of this EIA. Easton Broad Flood Management Project 3

8 4 What is the existing environment at the proposed development site? The Easton Broad Flood Management Project is located at Potter s Bridge, where the B1127 between the villages of Wrentham and Reydon crosses the Easton River, approximately 3km north of Southwold, Suffolk in the East of England (Ordnance Survey grid reference TM , Figure NTS 1). Potter s Bridge The proposed development site is located in the Easton River valley in an area specifically referred to as Easton Broad. The site is set within a gently undulating agricultural landscape. The majority of the site consists of reedbed to the north and south of the Easton River, which flows through the centre of the site to the coast which is about 1km to the east (Figure NTS 2). The proposed development area comprises 2.05 hectares, of which 2 hectares are to the east of the B1127 (Figure NTS 3) and encompasses a 26 metre wide corridor across the valley through the reedbed, parallel with the B1127, plus additional areas of arable land to the north and south. The proposed development site is located within a highly sensitive environment which is covered by a number of national and European designations (Figure NTS 4): Benacre to Easton Bavents SPA: This site is of European importance for its breeding populations of bittern and marsh harrier, two of Britain s rarest breeding birds; 4 Easton Broad Flood Management Project

9 Benacre to Easton Bavents Lagoons SAC: designated for its coastal lagoon habitat; Pakefield to Easton Bavents Site of Special Scientific Interest (SSSI): The site is nationally important for its coastal habitats, nationally scarce or rare plants, scarce breeding birds (including bittern, marsh harrier, little tern, water rail and bearded tit), and wintering bitterns; Benacre National Nature Reserve (NNR); Suffolk Heritage Coast; and Suffolk Coast and Heaths Area of Outstanding Natural Beauty (AONB). The site and surrounding area include habitats of importance for nature conservation, including reedbed and hedgerows, which support a number of protected or rare species, including otter, water vole, reptiles, and the narrow mouthed whorl snail, as well as the birds species for which the SPA and SSSI are designated. Easton Broad Flood Management Project 5

10 5 What does the proposed development comprise? The proposed development is illustrated on Figures NTS 5 and 6 and is expected to comprise the works and structures detailed below. Creation of two temporary construction compounds adjacent to the B1127 to the north and south of the reedbed. These will be provided for the duration of the works, and will be used for access, storage of machines and materials, and location of the site office and welfare facilities. They will be surfaced with crushed stone/concrete, which will be removed following completion of the embankment. Topsoil will then be replaced and the area sown with a species rich meadow grassland seed mix. Oak tree to be removed Removal of approximately 185m of hedgerows to provide safe access to the site compounds. These will be replanted once works are complete. Removal of one oak tree. This will be replaced by another oak tree which will be planted as close as possible to the location of the original once works are complete. Construction of a new clay embankment across Easton Broad reedbed (immediately adjacent to B1127). The embankment will be in two sections to the north and south of the Easton River (320 metres and 200m long respectively and 26m wide). The crest of the embankment will be 3.98m high (AOD 1 Above Ordnance Datum) and 4m wide falling to a 3m wide lower berm at 2m (AOD) on both the eastern and western sides. The embankment will be connected to the existing bridge using steel sheet piles which will be 3.68m high (AOD). The eastern wall of Potter s Bridge will be raised to this height with bricks matching the existing wall, making it about 2m high from the road surface. Following completion of the embankment, it will be covered with topsoil and sown with an appropriate grass seed mix. Where reeds do not establish naturally along the lower slope of the embankment, reeds will be planted to help integrate the structure within the existing landscape. Works to the culvert where the Easton River passes under the B1127 at Potter s Bridge including: 1 Ground levels and the heights of structures are often expressed as the height Above Ordnance Datum, which is the level from which altitudes on maps are measured, usually mean sea level. 6 Easton Broad Flood Management Project

11 o provision of a weed screen and hard standing to allow for weed removal (immediately upstream of the bridge), o installation of a water control structure on the upstream side of Potter s Bridge to allow water levels to be controlled in the reedbed upstream of the bridge. The structure will be constructed on a reinforced concrete slab placed on a steel sheet pile foundation, and will be connected to Potter s Bridge by steel sheet pile walls with a reinforced concrete cap. o provision of a secure pedestrian access platform over the structure to allow access to clear the weedscreen and operate the gate. o construction of access platforms either side of the water control structure. These will be raised to the height of the steel sheet pile wingwalls 2 (c m above ground level), and will provide vehicle parking and a machine working area to clear the weedscreen from heavy blockages. These will total c. 500m 2 and will be accessed via a new lay-by to be created adjacent to the B1127 north of Potter s Bridge. o Installation of a fish pass, allowing fish to travel along the Easton River through the new water control structure. o Installation of a new tidal flap, allowing for fish passage, on the downstream side of the bridge. Temporary diversion of the South Cove public footpath around the northern site compound. This footpath will be re-instated on its original route after the works are completed. This will take it over the top of the embankment. Provision of a viewing platform where the South Cove footpath and Suffolk Coast Path crosses the embankment. Provision of a footpath along the bottom of the embankment. This will follow the former route of the Suffolk Coast Path, and will run south from the South Cove Footpath, along the embankment, crossing the Easton River at Potter s Bridge. Provision of interpretation boards providing information on the habitats and species, landscape and history of the Easton Broad. It is proposed to undertake the works over six years during August to February (the exact timing will be dependent on when birds finish breeding and weather conditions) due to the potential for settlement of the embankment during the construction process. 2 Smaller retaining walls connecting Potter s Bridge and the water control structure. Easton Broad Flood Management Project 7

12 6 Consultation In recognition of the sensitive nature of the environment within which the site is located, extensive consultation has been undertaken with statutory bodies and stakeholders from the earliest stages of the Easton Broad Flood Management Project. Consultation undertaken included: Scoping Consultation Document issued (April/May 2011). The purpose of the document was to consult with statutory bodies and stakeholders on the key environmental issues that could require further consideration as part of the Environmental Impact Assessment for the Easton Broad Flood Management Project. Scoping Report Issued (January 2012). The purpose of the report was to confirm the proposed scope of work following feedback on the Scoping Consultation Document. The Scoping Report was issued to Waveney District Council with a request for a scoping opinion. Meeting with Natural England and RSPB (28 March 2012). Public drop-in at Reydon village hall (12 April 2012) to allow members of the public to find out more about the scheme and provide any comments. Meeting with the Suffolk County Council Highways Department (19 April 2012). Throughout the project the Environment Agency have worked particularly closely with Natural England and the RSPB in order to obtain information about the site and ensure that the scheme was designed in such a way as to avoid significant effects on the bird species or habitats for which the SPA, SAC and SSSI are designated. Key areas in which the scheme design has been influenced by consultation are summarised below. The timing of construction works has been designed to avoid effects on breeding birds (especially bittern and marsh harrier), following consultation with the RSPB and Natural England. A footpath is being provided along the lower berm of the new embankment, providing a safe route for pedestrians and allowing the reinstatement of the original route of the Suffolk Coast Path. The proposed footpath and the reinstated South Cove public footpath and Suffolk Coast Path will be fenced to prevent pedestrian access to the top of the embankment, which could disturb birds breeding within the adjacent reedbed. Where the reinstated South Cove public footpath and Suffolk Coast Path will cross the top of the embankment it will be screened to prevent disturbance to birds breeding within the adjacent reedbed. A water control structure at Potter s Bridge has been incorporated into the scheme design following feedback from Natural England to allow better control of water levels within the Easton Valley reedbed. A fish and eel pass will be incorporated into the proposed water control structure at Potter s Bridge to allow fish and eels to travel past the structure. The size of the working platforms adjacent to the water control structure have been minimised to reduce loss of reedbed habitat. Access to the working platforms will be directly off the B1127 for the same reason. Access to the site will be via the north only, following consultation with Suffolk County Council Highways Department, to avoid impacts on buildings within Reydon to the south. 8 Easton Broad Flood Management Project

13 7 What does the Environmental Impact Assessment Process involve? At an early stage in preparing its proposals for the proposed development, the Environment Agency recognised that, given the scale of development proposed and the sensitivity of the surrounding environment, the development required Environmental Impact Assessment under the EIA Regulations. A Scoping Consultation Document was prepared by the Environment Agency in April 2011 to identify the potentially significant environmental effects of the proposed scheme that needed to be assessed further and to outline the approach to undertaking the assessments of these effects. The report enabled statutory and non-statutory organisations and others with an interest in the proposed scheme ( stakeholders ) to comment on the proposed scope of the assessment. A Scoping Report was prepared by the Environment Agency in January 2012, which outlined the work that it was considered, at that time, was needed to assess the potentially significant effects of the proposed development. This report was issued to Waveney District Council (WDC) with a request for a scoping opinion. The scope of the assessment was refined in response to comments received on the Scoping Consultation Document, Waveney District Council s scoping opinion, and also in response to comments received through subsequent consultation, environmental information obtained from further survey and assessment work, and changes that were proposed to the proposed development design. The subsequent Environmental Statement includes an impartial assessment of the predicted environmental effects of the proposed development. To meet the requirements of the EIA Regulations, the assessment focuses on those effects that are potentially significant (both positive and negative), with a comparison being made between the likely environmental conditions in the presence of the proposed development and in its absence (i.e. the baseline situation). The Environmental Statement considers only the effects on the topics set out in Table 7.1, which were scoped into the Environmental Impact Assessment. 7.1 Issues scoped into the Environmental Impact Assessment of the Easton Broads Flood Management Project Environmental Topic Recreation Issue Effects on walkers using the Suffolk Coast Path due to the reinstatement of the path over Potter s Bridge. Effects on users of the Benacre NNR due to the provision of new facilities (a screened viewing platform and interpretation board). Biodiversity Effects on otter. Effects on water vole. Effects on reptiles. Effects on narrow-mouthed whorl snail. Effects on breeding and wintering bittern. Easton Broad Flood Management Project 9

14 Environmental Topic Issue Effects on breeding marsh harrier. Effects on breeding water rail and bearded tit. Effects on breeding bird assemblages of scrub and open water and their margins. Effects on Easton Valley reedbed (all 180ha), through improved management of water levels and enhanced fluvial drainage. Effects on Easton Valley reedbed (130ha) upstream of B1127, as a result of protection of the reedbed from saline intrusion. Landscape and visual impact Effects on landscape character. Effects on recreational users of the Benacre NNR as a result of changes in views. Effects on motorists using the B1127 as a result of changes in views. Water Effects of reduction in tidal flood risk as a result of the increased standard of protection. Effects of residual risk of flooding due to overtopping and/or breaching of the proposed embankment. Effects of potential increase in flood risk from the Easton River due to impedance for flood water flows and loss of floodplain storage arising from construction of the embankment. Effects of reduction in flood risk as a result of improved clearance of blockages at Potter s Bridge due to the installation of a weedscreen. Effects of surface water flood risk due to increased run-off. Effects of decreased flood risk arising from changes to the water level regime of Easton Broad Effects of changes in ground stability as a result of the weight of the embankment Effects of changes in water quality arising from the chemical nature of the materials used to construct the embankment Heritage Assets and Archaeology Effects on the undated embankment carrying the Lowestoft Road (B1127) due to the loss of archaeological information following the construction of hardstanding areas and/or surface levelling. Effects on medieval and Post-medieval land reclamation, including the drainage dykes and sluice structures, due to the loss of archaeological information following the construction of hardstanding areas and/or surface levelling. Effects on Post-medieval monumental features (Potter s Bridge) Effects on deposits of palaeoenvironmental and/or geoarchaeological significance due to loss as a result of ground compaction following embankment construction. Effects on previously unrecorded archaeological activity due to the loss of research materials and unknown assets through construction activity As the various elements of the proposed development will be built over a period of up to six years and then operated indefinitely, it cannot be assumed that existing environmental conditions in the absence of the proposed development will be the same as at present. This reflects changes resulting from human influences, such as new development, or natural processes which have the potential to modify current environmental conditions. Therefore, where existing environmental conditions are likely to change over these six years (for example as a result of coastal erosion), the assessment has predicted these future baseline conditions and the effects of the proposed development have been assessed against these. Where baseline conditions are unlikely to change, the effects of the proposed development are assessed against the existing baseline. Reaching a conclusion about which effects, if any, are likely to be significant is the result of an iterative process that involves the following stages: 10 Easton Broad Flood Management Project

15 1. identifying those effects that may be significant; 2. assessing environmental changes and any consequent effects on people, animal/ plant species or other receptors (for example archaeological remains); 3. determining whether or not these effects are likely to be significant; 4. identifying mitigation measures to avoid, or reduce any adverse effects identified (focussing on those considered to be significant); and 5. assessing the residual effects after implementation of mitigation measures. The findings of the assessment will assist Suffolk Coastal District Council, those that it consults and other stakeholders in coming to a view about whether or not and, if appropriate, how the proposed development should proceed. This decision-making is also part of the EIA process. All mitigation measures identified during the assessment process are included in an Environmental Action Plan, which must be complied with throughout the project, and will ensure that the measures to avoid and reduce environmental effects identified in the Environmental Statement are implemented. Easton Broad Flood Management Project 11

16 8 What are the predicted likely significant effects of the proposed development? The Environmental Statement has assessed the potentially significant effects, whether adverse or beneficial, on the human population (including visual effects and effects due to changes in recreational opportunities), plants and animals, soil, water, air, climate, material assets (such as archaeology or listed buildings - the historic environment ), landscape and the interrelationship between all of these factors. In this section, an overview of the baseline is provided followed by the likely significant effects identified, measures to minimise these effects (mitigation measures) are discussed and the effect with these measures in place (residual effect) is then provided. The results of the assessment are summarised below. 8.1 Recreation South Cove Public Footpath No.8 crosses part of the site immediately to the south of the northern construction compound. At the start of 2012 this footpath also formed part of the inland route of the Suffolk Coast Path, a 50 mile long distance route running between Felixstowe and Lowestoft. From the South Cove Public Footpath No.8 at Potter s Bridge, the Suffolk Coast Path continued southwards on the B1127 Lowestoft Road, before following a further footpath heading west past Smear Farm. However, since the start of 2012 the Suffolk Coast Path inland route has been temporarily diverted away from the Easton Broad and no longer follows this route. The majority of the site lies within the Benacre NNR, which provides recreational opportunities for visitors. Benacre National Nature Reserve 12 Easton Broad Flood Management Project

17 The following likely significant effects were identified. The provision of a footpath along the embankment which will allow the reinstatement of the Suffolk Coast Path along its original route, but in a safer location off the B1127, will have a significant beneficial effect on users of this long distance path. No mitigation is required as this is a beneficial effect. 8.2 Biodiversity The proposed development site is located in an area with a number of nature conservation designations, as set out in section 4. The reedbeds within and adjacent to the site provide habitat for the bird species for which these sites are important, including bittern, marsh harrier, water rail and bearded tit. The site also provides habitat for a number of species which are either protected or which are of nature conservation importance, including otter, water vole, reptiles (slow worm, common lizard and grass snake) and invertebrates (specifically the narrowmouthed whorl snail). The site also contains the following habitats which are a priority for nature conservation; hedgerows and arable field margins. The following likely significant effects were identified. Fragmentation of otter habitat as a result of the new embankment. It is not possible to mitigate for fragmentation of otter habitat by providing, for example, an otter pass under the embankment, as this would allow seawater to pass through the embankment. Disturbance to resting otter due to human activity, noise and vibration during construction. A predevelopment check will be undertaken before commencement of each phase of works to determine whether otters are using any resting places within the site. If an active resting place is found, no works will be undertaken within 50m of this site. As a result there will be no significant effect. Risk of destruction/damage to water vole nests and/or burrows and/or accidental killing or injury of water voles during construction. Measures will be taken to exclude water voles from the area of works. As a result there will be no significant effect. Risk of accidental killing or injury of reptiles during construction. Measures will be taken to exclude reptiles from the area of works. As a result there will be no significant effect. Risk of accidental killing and loss of habitat for narrow-mouthed whorl snail (a UK Biodiversity Action Plan species) due to habitat loss during construction. Vegetation containing snails will be removed from the area of works and scattered in a number of pre-agreed receptor sites. As a result there will be no significant effect. Increased availability of habitat for narrow-mouthed whorl snail due to the creation of the embankment. Improved quality of habitat for narrow-mouth whorl snail due to improved management of water levels in 130ha of reedbed habitat (for up to 50 years). Easton Broad Flood Management Project 13

18 Disturbance of wintering bittern during construction. Bittern are particularly vulnerable to disturbance during freezing weather when feeding conditions are poor. Construction will cease during freezing weather to avoid disturbance to bittern. As a result there will be no significant effect. Protection (for up to 50 years) of 130ha of reedbed habitat for bittern, marsh harrier, water rail, bearded tit, breeding birds for which the Pakefield to Easton Bavents SSSI is designated, otter, water vole and which would otherwise deteriorate in quality and eventually be lost as a result of flooding by seawater. Protection of 130ha of reedbed habitat for up to 50 years by preventing seawater travelling upstream of Potter's Bridge. Improved quality of 130ha of reedbed due to improved management of water levels. After implementation of the mitigation described above, the following residual significant effects are likely. Permanent further fragmentation of otter habitat as a result of the new embankment. Permanent increase in the availability of marginal habitat for narrow-mouthed whorl snail due to the creation of the embankment. Improved quality of habitat for narrow-mouth whorl snail due to improved management of water levels in 130ha of reedbed habitat (for up to 50 years). Protection (for up to 50 years) of 130ha of reedbed habitat for bittern, marsh harrier, water rail, bearded tit, breeding birds for which the Pakefield to Easton Bavents SSSI is designated, otter, water vole and which would otherwise deteriorate in quality and eventually be lost as a result of flooding by seawater. Protection of 130ha of reedbed habitat for up to 50 years by preventing seawater travelling upstream of Potter's Bridge. Improved quality of 130ha of reedbed due to improved management of water levels (for up to 50 years). 8.3 Landscape and visual effects The site is located within an area designated as the Suffolk Coast and Heaths AONB and Heritage Coast and forms part of the rural landscape which separates the settlements of Reydon (approximately 1km to the south) and Wrentham (approximately 2km to the north). Although the landscape surrounding the site is typically pastoral fields, much of the site itself, which is centred on Easton River, is within a localised lowpoint and is wetter than the surroundings resulting in the creation of a reedbed landscape. As such, the site has a very tranquil and remote character. 14 Easton Broad Flood Management Project

19 View of the site from Potter s Bridge Within the site itself, open and expansive views across the reedbeds to the surrounding landscape are possible from the B1127 and from the paths through the Benacre NNR. Despite the open views within the site itself, the site as viewed from the surrounding landscape is well screened. This is due in part to the topography, as the site lies in a low point, with land rising to the north and south, away from the site containing views. Vegetation in the form of overgrown hedgerow and hedgerow trees also plays a key role in containing views and providing screening. The following likely significant effects were identified. Temporary changes to the landscape character of the local area during construction of the embankment. Measures will be implemented to minimise these effects, including appropriate location of contractors compounds and material stock piles, and regular removal of construction related litter. However, effects during construction are still considered to be significant. Permanent changes to the landscape character of the local area immediately following construction of the embankment. Measures will be implemented to minimise these effects, including ensuring that the proposed fencing and gate along the edge of the lay by area to the west of the road are constructed of materials to compliment the landscape. As a result there will be no significant effect. Temporary changes to the views experienced by people using the Benacre NNR during construction of the embankment. Measures will be implemented to minimise these effects, including appropriate location of material stock piles and buildings within contractors compounds. However, effects are still considered to be significant. Permanent changes to the views experienced by people using the Benacre NNR immediately following construction of the embankment, and 15 years after Easton Broad Flood Management Project 15

20 completion. Measures will be implemented to minimise these effects, including; replacement reed planting along the embankment if reeds do not establish naturally; seeding of the embankment with grass seed; cladding of the sheet piling with brick matching the existing Potter s Bridge. As a result there will be no significant effect. After implementation of the mitigation described above, the following residual significant effects are likely. Temporary changes to the landscape character of the local area during construction of the embankment as a result of the presence of construction compounds, machinery and the embankment in construction. Temporary changes to the views experienced by people using the Benacre NNR during construction of the embankment as a result of the presence of construction compounds, machinery and the embankment in construction. 8.4 Water resources and flooding The Easton River flows through the centre of the site, and a number of small drainage ditches are also to be found across the site. The majority of the site is low lying, and water levels are maintained a slightly above ground level throughout the reedbeds. Anecdotal information on historical floods provided by Natural England suggests that the B1127 road floods approximately six to seven times a year from the Easton River, and three to four times over the past decade from the sea. The following likely residual significant effects were identified. Reduced risk of flooding of the reedbed upstream of Potter s Bridge, the Easton River, B1127, footpaths, Potter's Bridge and residential properties and land by the sea due to the creation of the embankment. Reduced risk of flooding of the Easton valley reedbed due to improved control of water levels. No mitigation is required as these are beneficial effects. The scheme is considered to be compliant with the requirements of the Water Framework Directive. 8.5 Historic environment The site is unlikely to be a location for early settlements, due to its location in a lowlying, waterlogged valley. The site is part of an early sea defence embankment and formed a route through the marshes, with links to local villages and market towns, including Easton Bavents. The existing, Post-medieval Potter s Bridge (an undesignated historic asset) is likely to exist on an earlier river crossing point. There is cropmark evidence to suggest that phases of drainage and peat extraction may have begun in the medieval period. Historically, reclaimed marshlands were important pastures, although there is a possibility that the fen peats in the valley bottom have also been extracted. 16 Easton Broad Flood Management Project

21 Easton Bavent (Bowen and Hodskinson maps, 1755) The following likely significant effects were identified. Permanent adverse effects on the historic integrity and setting of Potter s Bridge (a Post-medieval monumental feature) due to the construction of the embankment. Measures will be implemented to minimise these effects, including use of matching bricks to face the adjacent piling. As a result there will be no significant effect. Potential loss of unrecorded archaeological activity due to construction activity. To mitigate for this, and archaeological watching brief will be implemented during any excavation. As a result, there will be no significant effect. As a result of implementation of the mitigation described above, there are no predicted residual significant effects after mitigation. 8.6 Cumulative and in-combination effects Cumulative effects The EIA Regulations require that cumulative effects (i.e. the combined effects of the proposed scheme with other developments or environmental changes which will occur during the construction or operation of the proposed scheme) are assessed within an EIA. Cumulative effects have been considered in this ES through the inclusion of other schemes and/or other land use/environmental changes that are likely to happen over the same time period as the proposed scheme within the future baseline for each environmental topic, against which the effects of the scheme are assessed. There are no developments or other schemes which may affect the future baseline. However, environmental changes resulting from the removal of maintenance to the shingle ridge have been considered in the future baseline, and are therefore included in the assessment of effects provided above. Easton Broad Flood Management Project 17

22 In-combination effects Effects on a number of environmental receptors have been assessed in relation to more than one environmental topic. A summary of the significant residual effects which are predicted to occur on these receptors is provided below. Users of Benacre NNR Temporary changes to the views experienced by recreational users of the Benacre NNR during construction of the embankment as a result of the presence of construction compounds, machinery and the embankment in construction. Users of the Suffolk Coast Path Increased safety of walkers using the reinstated Suffolk Coast Path. Reduced risk of flooding by the sea due to construction of the embankment. Users of the B1127 Reduced risk of flooding by the sea due to construction of the embankment. Easton Valley reedbed Protection of 130ha of reedbed habitat for up to 50 years by preventing seawater travelling upstream of Potter's Bridge. Improved quality of 130ha of reedbed due to improved management of water levels (for up to 50 years). Potter s Bridge Reduced risk of flooding by the sea due to construction of the embankment. B1127 and embankment Reduced risk of flooding by the sea due to construction of the embankment. 18 Easton Broad Flood Management Project

23 9 Conclusions The assessment has shown that the following temporary and permanent significant adverse residual effects are likely. Temporary effects: Temporary changes to the landscape character of the local area during construction of the embankment as a result of the presence of construction compounds, machinery and the embankment in construction. Temporary changes to the views experienced by recreational users of the Benacre NNR during construction of the embankment as a result of the presence of construction compounds, machinery and the embankment in construction. Permanent effects: Further fragmentation of reedbed used by otters for foraging and resting as a result of the new embankment. The assessment has shown that the following permanent significant beneficial residual effects are likely. Increased safety of walkers using the reinstated Suffolk Coast Path. Protection of 130ha of reedbed habitat for up to 50 years by preventing seawater travelling upstream of Potter's Bridge. Improved quality of 130ha of reedbed due to improved management of water levels. Protection (for up to 50 years) of 130ha of reedbed habitat for bittern, marsh harrier, water rail, bearded tit, breeding birds for which the Pakefield to Easton Bavents SSSI is designated, otter, water vole and which would otherwise deteriorate in quality and eventually be lost as a result of flooding by seawater. Increased availability of habitat for narrow-mouthed whorl snail (directly affected by the scheme) due to the additional marginal habitat area provided by the creation of the proposed embankment. Improved quality of habitat for narrow-mouth whorl snail (directly and indirectly affected by the scheme) due to improved management of water levels in 130ha of reedbed habitat (for up to 50 years). Reduced risk of flooding of the B1127, footpaths, Potter's Bridge and residential properties and land by the sea. Easton Broad Flood Management Project 19

24 10 Where can more information be found? For more details on this project, please contact the Environment Agency s Project Manager: Adam Thurtle Environment Agency Dragonfly House 2 Gilders Way Norwich NR3 1UB Telephone: Easton Broad Flood Management Project

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28 N Benacre to Easton Bavents SPA Outer Thames SPA Key: Site Boundary Pakefield to Easton Bavents Site of Special Scientific Interest (SSSI) Benacre to Easton Bavents Special Areas of Conservation (SAC) Benacre National Nature Reserve (NNR) Special Protection Areas (SPA) Ramsar Sites Note - The Suffolk Coast and Heaths Area of Outstanding Natural Beauty covers the whole of the area shown. Environment Agency Crown copyright All rights reserved. Special licence number Z Kilometres Scale: A3 Easton Broad Flood Management Project Environmental Statement Non-Technical Summary Figure NTS 4 Statutory designations June L56.mxd tugwc

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