Medmerry Managed Realignment Environmental Statement Non-Technical Summary. Final. Reference number/code IMSO Environment Agency Title

Transcription

1 Medmerry Managed Realignment Environmental Statement Non-Technical Summary Final Reference number/code IMSO Environment Agency Title

2 We are The Environment Agency. It's our job to look after your environment and make it a better place - for you, and for future generations. Your environment is the air you breathe, the water you drink and the ground you walk on. Working with business, Government and society as a whole, we are making your environment cleaner and healthier. The Environment Agency. Out there, making your environment a better place. Published by: Environment Agency Rio House Waterside Drive, Aztec West Almondsbury, Bristol BS32 4UD Tel: enquiries@environment-agency.gov.uk Environment Agency All rights reserved. This document may be reproduced with prior permission of the Environment Agency.

3 Non-Technical Summary i. Introduction and Background The aim of this Environmental Statement (ES) is to document the statutory Environmental Impact Assessment (EIA) of the proposed Medmerry Managed Realignment scheme. The screening process has identified that the works are likely to give rise to significant environmental effects and, therefore, require a statutory EIA under the Town and Country Planning EIA Regulations SI 99/293. The ES has been prepared with reference to the Environment Agency s EIA guidance and work instruction. Medmerry is located between East Head and Selsey Bill, on the Selsey Peninsula, in West Sussex on the south coast of England (see Location Plan below). Managing flood risk along this frontage is crucial to the future of the town of Selsey and the peninsula s low-lying villages and holiday parks. Without the existing shingle storm ridge defence, large areas of land would flood on each tide, Selsey s only road link would be severed and the waste water treatment works situated in the Medmerry floodplain would be flooded. Medmerry Location Plan Current management practices have not been completely effective in managing the risk along the entire frontage, and regular recycling of material and major beach re-profiling is needed at Medmerry each winter to maintain the existing shingle ridge defence. Even i

4 with this maintenance the shingle bank remains vulnerable and provides a low standard of protection, providing protection only for events, which could be expected to occur once every year. The local community remains vulnerable to more extreme events. As sea levels rise, holding the line of the shingle bank will become more costly and the risk of a breach and flooding will increase. The shingle bank will, therefore, not provide an effective defence over the next 100 years. The current and future risk along the Medmerry frontage has been investigated as part of the Pagham to East Head Coastal Defence Strategy (Environment Agency et al., 2008a). A number of flood risk management options were initially considered for the frontage in the Strategic Environmental Assessment (SEA) for the Strategy, including no active intervention, hold the line and managed realignment. The Strategy, supported by the SEA, concluded that a preferred option for the frontage was to manage coastal flood risk through managed realignment. This proposed scheme will implement the Strategy s preferred option and will provide a greatly improved standard of protection against coastal flooding (protection to at least 1 in 100 (1%) chance of flooding in any given year). The scheme will build new defences inland from the coast, undertaking a deliberate breach of the shingle bank and allow a new intertidal area to form between the shingle bank and these new defences. Drainage channels will be excavated behind the inland flood embankments to manage surface water flood risk and within the site to optimise the flooding and draining of the site, and ensure the breach remains open. As well as the significant flood risk benefit provided by the scheme, it will also create mudflats, saltmarshes, saline lagoons and transitional habitats which are under threat around the UK due to the effects of climate change and sea level rise. The objectives of the scheme are as follows: To provide a sustainable Flood and Coastal Erosion Risk Management scheme with an appropriate standard of protection as quickly and safely as possible; To maximise the creation of new intertidal habitat to offset losses across the Solent, taking climate change into account, and to optimise freshwater habitat creation, making best use of existing topography to provide a sustainable solution; and To encourage community participation during the planning and development phase to deliver a scheme that can be supported by the community. For this project a detailed options appraisal phase was undertaken on the findings of the Strategy to consider a number of rear wall alignments, breach scenarios and internal drainage designs with respect to technical, economic and environmental constraints. The preferred option and its key features are shown in the Landscape Masterplan on Page iii. Further details of the scheme are provided in Figures 1 and 2 in Appendix A of the ES. Detailed construction drawings are included in Appendix B of the ES. ii

5 Landscape Masterplan iii

6 Consultation with internal and external stakeholders has been undertaken throughout the EIA, including a number of public exhibitions, meetings, a dedicated Medmerry webpage and press releases in local newspapers. A Medmerry Stakeholder Advisory Group (MStAG) and dedicated Habitat Creation Group have been established. These groups have worked with the Environment Agency as the scheme has progressed, providing feedback and assisting the selection of the preferred option, the design and development of the scheme and the EIA. Given the high risk of the shingle defence failing and the potential for flooding at Medmerry, there is a pressing need to carry out the scheme to improve flood protection as soon as possible. The Environment Agency is, therefore, seeking to commence construction in ii. The Existing Environment Medmerry is located between East Head and Selsey Bill, on the Selsey Peninsula, in West Sussex (National Grid Reference SZ834949) on the south coast of England (see Location Plan on Page i). A distinctive landscape feature of a large part of the surrounding area is its remote and tranquil character. The towns of Selsey and East Wittering are located to the east and west of the site respectively, and there are a number of smaller villages in the area, including Bracklesham and Church Norton. There are also a small number of neighbouring privately owned properties, namely at Ham and Earnley. Bunn Leisure is located southeast of the Medmerry Managed Realignment site, comprising four caravan parks and one of the largest holiday complexes in Europe. Sussex Beach Holiday Village lies to the west of the Medmerry Managed Realignment scheme. A major waste water treatment works is located between Selsey and Sidlesham, serving Selsey and the surrounding area. The principal roads in the area are the B2145, which links Selsey with the A286 and the A27 (T) Chichester By-Pass. To the northwest, the B2198 connects Bracklesham with the A286. Between these a network of minor roads and tracks provide access to the many farms in the area. From the east, access to the Medmerry frontage is provided by Medmerry Beach Road, which runs through the Bunn Leisure site, and there are public footpaths, which provide access to the site from Selsey, Earnley and the adjacent caravan park. The proposed site comprises primarily agricultural land (mainly Grade 3 according to the Department of Environment, Food and Rural Affairs (Defra) Agricultural Land Classification (ALC)), a small area of coastal freshwater wetland, the rifes (drainage channels) and associated reed beds, and some vegetated shingle habitat. The entire frontage at Medmerry is part of Bracklesham Bay Site of Special Scientific Interest (SSSI), which is designated for its unimproved grazing pastures that support important bird populations and also valued for its geological importance. This SSSI comprises a Royal Society for the Protection of Birds (RSPB) reserve, part of which falls within the Medmerry Managed Realignment site. There are no Scheduled Monuments, Listed Buildings, Registered Parks or Gardens, Registered Battlefields or Conservation Areas present in the proposed footprint of the Medmerry Managed Realignment scheme. A small number of low sensitive heritage assets have been identified in the proposed site, primarily products of the development of the Second World War defensive landscape (e.g. pill boxes). iv

7 iii. Environmental Impacts and Proposed Mitigation Measures The Environment Agency considers the environmental impact of its projects and seeks ways to improve the environment where possible. In November 2009 a Scoping Study was carried out to identify the key issues within the study area. A summary of the issues that were raised by consultees in response to the Scoping Consultation Document is provided in Appendix F of the ES. Following consultation, an assessment was undertaken to evaluate the impact of the Medmerry Managed Realignment scheme and identify ways to reduce any adverse impact. An Environmental Action Plan (EAP) has also been produced so that environmental issues identified in this assessment are managed before, during and after construction. The EAP is included in Appendix R of the ES. The Medmerry Managed Realignment scheme will provide a number of positive impacts both to the community and ecology of the area. The key significant (moderate to major) beneficial impacts that the scheme will result in are as follows: An improved standard of protection against flooding which will greatly reduce the risk of injury and potential loss of human life to the local community and general public. It will also reduce the risk of damage to property and infrastructure through flooding; Provision of a low impact green tourist attraction that will result in increased physical, quality of life and well being benefits to the local community and visitors, as well as a long term socioeconomic benefit to the area; An improved access network will be created as part of the scheme, linking Bracklesham and Selsey via Medmerry, which will provide major recreational benefits to both locals and visitors, with subsequent benefits to the local economy; The creation of a mosaic of different habitats, including intertidal habitat that is currently being lost across the Solent due to coastal squeeze; The creation of brackish and marine habitats will support a variety of marine fish and invertebrate species, which in turn will attract a variety of feeding, loafing and roosting waterbirds; Isolated areas of higher ground (e.g. islands) will provide a benefit to ground nesting birds; and The elimination of the physical disturbance resulting from existing re-profiling works along the shingle bank will provide the opportunity for the UK BAP priority habitat, coastal vegetated shingle habitat, to develop and become established. The key significant (moderate to major) adverse impacts have also been identified and are summarised below, along with ways to reduce their impact (mitigation measures). Table i. Summary of key adverse impacts, corresponding mitigation measures and residual impacts Impact Description (No Mitigation) Proposed Mitigation Residual Minor Moderate Major (Adverse) Minor Moderate Major (Beneficial) Negligible = Population Potential safety risks for local residents, construction workers and operations personnel Health and safety risk associated with the main All site compounds and working area boundaries will be clearly defined and signage will be placed at appropriate points warning of possible hazards. A construction management plan will also be produced. Signage clearly indicating the risks of the tidal flows and potential for stranding will be placed v

8 Impact Description (No Mitigation) Proposed Mitigation Residual Minor Moderate Major (Adverse) Minor Moderate Major (Beneficial) Negligible = breach during operation Extinguishment and diversion of footpaths no. 70 and 75 respectively during operation Permanent loss of existing emergency access between Selsey and Earnley Permanent loss of existing (informal) coastal access route Flora & Fauna Loss or damage of unimproved grazing pastures and lowland wet grassland SSSI features Loss or damage of unimproved grazing pastures and lowland wet grassland SSSI features during operation Physical disturbance to habitats that support birds Permanent loss or damage of Nationally Scarce plant species Permanent loss or damage of Nationally Scarce plant species during operation UK Biodiversity Action Plan (BAP) terrestrial invertebrate species on either side of the main breach. A new and improved extensive footpath network has been included in the design of the scheme, in discussion with the Public Rights of Way Officer, which will provide alternative routes to walkers. Viewpoints will also be provided at certain points along the new flood embankment. / / In discussion with the emergency services, a new and improved emergency vehicular access route will be provided by the scheme. In discussion with Natural England, a new coastal access route will be provided by the scheme, which will avoid areas that are considered particularly sensitive for wildlife. In consultation with Natural England and RSPB, areas of coastal grazing marsh habitat will be created to compensate for the loss of this habitat within the SSSI. This habitat will be designed to maximise biodiversity benefits and will include the provision of undisturbed wildlife areas. All works will be undertaken in line with Environment Agency requirements, including an environmental clerk of works. Areas where construction work is proposed will be cleared of vegetation outside the main bird nesting season and the main breach will be undertaken outside the winter and spring period to minimise disturbance to both breeding and overwintering birds. Gas guns will be deployed, as necessary, to create regular loud bangs that will further deter ground nesting birds from using areas that are being worked. Work patterns and timings will also be varied to avoid damage or destruction of nesting attempts during the land profiling. Areas of higher ground within the site will be maintained as both grazed and ungrazed grassland to mitigate for the loss of existing grassland and farmland habitat supporting protected plant species. The areas of freshwater habitat that will be created to = compensate for the loss of SSSI coastal grazing marsh habitat will also have the potential to support these protected plant species. Suitable nesting areas for the UK BAP saltmarsh bee will be established away from the future high water line prior to construction. The existing nesting area will be removed prior to the breach and translocated onto suitable / = vi

9 Impact Description (No Mitigation) Proposed Mitigation Residual Minor Moderate Major (Adverse) Minor Moderate Major (Beneficial) Negligible = protected reptile species and their supporting habitat protected reptile species and their supporting habitat during operation protected great crested newts and their supporting habitat protected great crested newts and their supporting habitat during operation Notable aquatic beetle species during construction protected water voles and their supporting habitat protected water voles and their supporting habitat during operation / / substrate. The UK BAP saltmarsh bee forages on sea aster, which is also very palatable to grazing animals, and so part of the site will remain outside any grazing regime between June and October, when these bees are active. Construction works will be undertaken in line with Environment Agency requirements, including an environmental clerk of works. Displacement techniques will be used to mitigate for the construction impacts on key areas of suitable reptile habitat. The main breach of the shingle bank will take place on a neap tide, which will enable reptiles to be displaced from the inundation zone in a progressive manner. Reptiles will also be trapped in key areas and released to suitable areas of higher ground, which will be maintained as both grazed and ungrazed grassland. All works will be undertaken in line with Environment Agency requirements, including an environmental clerk of works. A site-specific European protected species licence will be required from Natural England. Mitigation will involve the installation of exclusion fencing, trapping, translocation and habitat creation. Suitable potential receptor sites will be created within the managed realignment site to compensate for the loss of supporting habitat. Temporary and permanent pollution prevention measures, in accordance with the Environment Agency s Pollution Prevention Guidelines will be incorporated into the construction methods. Best practice guidelines will be adhered to, and effective sustainable urban drainage systems will be used during the construction phase to minimise pollution, contamination and sedimentation impacts on receiving waters. Construction works will be undertaken in line with Environment Agency requirements, including an environmental clerk of works. In consultation with water vole experts and Natural England, exclusion techniques will be used to mitigate for the construction impacts on key areas of suitable water vole habitat, particularly on watercourses impacted during the construction of flap valves, excavation of material and where the construction of embankments impinges upon ditch habitats. Water vole habitat will be created as part of the scheme to mitigate for the loss of supporting habitat within the realignment site. A system of ponds and ditches will be created at suitable locations both inside and outside the embankments. The ditch that will be constructed around the perimeter of the flood embankment will also be designed to support water voles and minimise fragmentation of populations. Water voles can also use intertidal habitats and, therefore, the saltmarsh and vii

10 Impact Description (No Mitigation) Proposed Mitigation Residual Minor Moderate Major (Adverse) Minor Moderate Major (Beneficial) Negligible = Fisheries Disturbance to fish in the rifes as a result of reduced water quality during construction Air, Climate & Noise Temporary elevated noise at Bunn Leisure site, Sussex Beach Holiday Village and Greenwood Farm Temporary elevated vibration at Bunn Leisure site Soil, Geology & Hydrogeology Loss or disturbance to geological SSSI features Landscape & Visual Amenity Visual impact of site compound and associated access road to footpath no. 76 Landscape and visual impact of car parks Visual impact of flood embankment on footpaths no. 70 and 75 / / / transitional grassland habitats resulting from the scheme are expected to provide additional, alternative supporting habitat (Charlie Smith, Environment Agency, pers. comm.). Temporary and permanent pollution prevention measures, in accordance with the Environment Agency s Pollution Prevention Guidelines will be incorporated into the construction methods. Best practice guidelines will be adhered to, and effective sustainable urban drainage systems will be used during the construction phase to minimise pollution, contamination and sedimentation impacts on receiving waters. A construction management plan will be developed in consultation with Chichester District Council. This is anticipated to include an agreed schedule for noise and vibration monitoring and established noise and vibration limits, as well as a number of potential mitigation measures. Following advice from Natural England, the footprint of the construction works along the foreshore will be kept to a minimum. Shingle blankets or protective mats will be used on new areas of plant movement along the beach to reduce compression and disturbance of the clay layer underneath the sand. Any geological interest features that are exposed will be carefully stored, in order that they can be examined and recorded. = A number of mitigation measures are proposed to reduce the adverse visual and landscape impacts to an acceptable standard. These include localised hedgerow planting between / the footpaths and the flood embankment, grass =/ seeding the embankment and the provision of at least one viewpoint south of Ham Farm to mitigate for the extinguishment and diversion of / the footpaths within the footprint of the scheme. =/ = iv. Environmental Enhancements The Medmerry Managed Realignment scheme as a whole is considered to be an environmental enhancement and is based on the desire to achieve a natural and sustainable environment, building on 20 years of experience of managed realignment work in the UK. viii

11 Medmerry has been highlighted as one of the main potential sites for intertidal habitat creation that will aid in offsetting coastal squeeze losses brought about by the implementation of Environment Agency and other Local Authorities flood and coastal erosion risk management schemes elsewhere within the area covered by the North Solent Shoreline Management Plan (SMP). It will also help improve the condition of the coastal SSSIs in the Solent area, a large percentage of which are in unfavourable condition, largely due to coastal squeeze. The scheme will, therefore, also contribute to the Government s Public Service Agreement (PSA) target to bring into favourable or recovering condition 95% of the area of SSSIs in England by December An integrated public access network will be provided as part of the scheme to provide enhanced access for multiple users, including walkers, cyclists and horse riders. Opportunities to integrate the scheme into the landscape and visual setting through habitat creation and planting will be achieved to further improve the recreational and health value of the site, and reduce any visual disturbance to adjacent properties. A Health Impact Assessment (HIA) has been undertaken which has identified the physical, quality of life and well being benefits of the scheme through the provision of a green tourism feature to the region. This is included in Appendix I of the ES. Additional areas for habitat creation will be provided as part of the Medmerry Managed Realignment scheme. The excavation of creek systems within the site, for example, have been designed to help the site flood and drain, and, therefore, ensure the breach remains open, but they also provide additional intertidal habitat. Freshwater habitat that will be created in order to compensate for the loss of SSSI coastal grazing marsh habitat within the site will also be designed to enhance biodiversity benefits and include the provision of undisturbed wildlife areas. The drainage ditch that will be created along the perimeter of the flood embankment will be designed sensitively for water voles, and landscaping provisions around the edges of the tidal influence will provide additional potential mitigation habitat for water voles, as well as new habitat for a range of lagoonal species. Further sheltered and isolated habitat for birds, such as islands, will also be created as part of the scheme. Their design and location will be considered further during the construction phase, and will need to take account of the objectives of the scheme, as well existing ground conditions. v. Conclusion The Medmerry Managed Realignment scheme will fulfil its ultimate objective and provide a sustainable Flood and Coastal Erosion Risk Management scheme with an improved standard of protection against flooding. The new realigned defences will provide protection to at least 1 in 100 (1%) chance of flooding in any given year over the next 100 years for properties at Selsey, Bracklesham, Ham and Earnley, and the Sidlesham waste water treatment works and B2145. In addition, the scheme has incorporated a range of surface flood drainage solutions to ensure the Medmerry Managed Realignment scheme maintains and potentially improves the management of surface water flood risk for the surrounding area. The Medmerry Managed Realignment scheme has also sought to maximise (in terms of greatest extent) the creation of new compensatory intertidal habitat to offset losses across the Solent and optimise freshwater habitat creation, taking climate change into account, and making best use of existing topography to provide a sustainable solution. A naturally functioning complex mosaic of habitats will be created by the scheme, including tidal channels, mudflat, saltmarsh, saline lagoons, freshwater ponds and ditches, isolated areas of habitat (islands), transitional grassland and terrestrial grassland. These habitats have been designed to maximise biodiversity benefits, support protected species that ix

12 have been relocated as a result of the scheme and include the provision of undisturbed wildlife areas. One of the defined project objectives is to encourage community participation during the planning and development phase to deliver a scheme that can be supported by the community. In order to do this, an extensive programme of stakeholder engagement was developed through written and verbal consultation with both statutory and non-statutory consultees, as well as the general public. This has assisted the selection of the preferred option and its design, and the development of the EIA, and will be continued during the construction phase. The Environment Agency has also facilitated the formation of an aspirations group, involving a range of statutory and non statutory consultees, including local community interest groups, to discuss further aspirations for the surrounding area that will make links with the scheme. In addition to the flood risk management benefits provided by the scheme, the proposed environmental enhancements will improve recreational facilities, wildlife habitats and landscape quality. The scheme will, however, also give rise to a number of adverse impacts. The majority of these impacts will occur during the construction phase, and as such will be temporary in nature. Mitigation measures will be employed to manage and reduce the impacts wherever possible. The residual adverse effects that remain following mitigation are on the whole considered not to be worse than minor adverse. Overall, the Medmerry Managed Realignment scheme will have a long-term beneficial impact for the area. x

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