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Marine and Coastal Topic Paper Series 2010 Coastal Defence

Dorset has a dynamic coastline: in the past, uninterrupted coastal processes created some of its most beautiful and important features . However, the issue of coastal retreat in this area was first recorded in 1366 at . Erosion and flooding by the sea are hazardous to property and infrastructure on the coast, and so there will always be demands for coastal defence works to protect property. This will mean that natural processes are inevitably interrupted. Data regarding climate change and sea level rise (SLR) suggest that these natural processes will accelerate during the 21st century and this will place greater pressure on both available finances and engineering solutions.

Balancing the desire to protect property whilst maintaining the integrity of the natural coast requires creative engineering solutions, and difficult decisions have to be made about where and how to protect.

• Coast protection works which protect the processes in neighbouring coastal against erosion. This is where the process units. land behind the works is higher than Sediment cell is a term frequently used any expected tidal flooding level. with regards to Shoreline Management These works are carried out under the Plans. It indicates a section of coastline Coast Protection Act 1949 and its associated nearshore area within which the movement of coarse sediment Coastal defence is a broad term used to (sand and shingle) is largely self- include both flood defence and coast contained. The movement and behaviour protection . of sand and shingle within one cell should Flood defence (river and sea) refers to not significantly affect beaches in a systems (including both hard engineering neighbouring sediment cell, but this

Gabion filed wire baskets. Copyright: as well as management methods) that demarcation is rarely clear-cut because a Dorset Coast Forum reduce the risk of flooding of land. number of cells might be arranged as part Coast protection refers to systems and of a single coastal process unit. Terminology structures such as sea-walls, promenades Coastal Change Management Areas There are two different types of coast etc, that stabilise the coastline and reduce (CCMA). Under new (July 2009) planning defence works and the terminology is the risk of loss to land and property policy, all inappropriate residential often used interchangeably. There are: caused by erosional processes and / or development, such as housing, will encroachment by the sea. continue to be banned in areas vulnerable • Sea defence works which are works Sea and tidal defence refers to systems to coastal erosion. But there will no longer which protect against flooding of the that prevent (usually temporary) flooding be a blanket ban on temporary land and are carried out in accordance of sea water over land. development that has wider economic with the Land Drainage Act 1991 Coastal process units are defined as a benefits, an acceptable coastal use and length of shoreline in which the physical could be relocated when required. processes are relatively independent from Planning authorities have to define the 1

Dorset Marine and Coastal Topic Paper Series 2010 Coastal Defence

'Coastal Change Management Area' in powers. The Environment Agency (EA) there are still a number of areas, such as which the policy applies. has the responsibility of approving all social benefit and public access, where it Shoreline Management Plans (SMP’s), is less straightforward to reach a Natural processes and natural hazards allocate funding for new or ongoing satisfactory assessment of costs vs Natural forces (wind, wave, tide and coastal defence works and assisting local benefits. The Dorset coastline is regarded current) shape Dorset’s coastline and give authorities in completing defence works. as probably the most valuable tangible rise to two groups of hazards which can asset that the County has in generating affect coastal property: Costs and Benefits tourism income. Therefore, the socio- Defra / EA policy is that publicly funded economic benefits /disbenefits must be • Coastal erosion is the process that coastal defence schemes must typically considered when new engineering cuts, shapes and retreats our cliff achieve a cost / benefits ratio of schemes are proposed, especially if ‘hard’ coastlines. On much of the Dorset approximately 1:5. This means that a schemes are being considered. coast, erosion is accompanied by £10M scheme must be able to landslips, including some of the largest demonstrate that £50M of infrastructure The legislative and grants application and most active in Europe. will be fully protected. National guidelines process for obtaining funds for coastal The lead responsibility for assessing and are set for the cost calculations. However defence works is becoming more stringent (where appropriate) controlling erosion (commonly referred to as coast protection ) lies with the District and Unitary Councils.

• Flooding - property can be affected by seawater inundation brought about by high tides or swamping with large waves - or often a combination of the two. The times of greatest risk are during spring high tides when accompanied by low-pressure storm surges and high winds from the south west, south or south east.

The Environment Agency has ultimate responsibility for managing coastal flood and erosion risk, although District/Unitary Councils do have some permissive

Beach replenishment at Overcombe Beach, Weymouth. Copyright: Dorset Coast Forum 2

Dorset Marine and Coastal Topic Paper Series 2010 Coastal Defence

and a points system is employed based maintenance requirement. The design life vulnerable to flooding include upon: requirement for a new sea-wall is usually Christchurch, West Bay, Chiswell and o The type of scheme: flood defence 60-70 years and this figure assumes full Weymouth. is the highest priority, and urban and ongoing maintenance throughout the coast defence is a higher priority working life of that structure. However, it is Within the last 10 years, new or upgraded than rural unlikely that those protecting the large coast protection schemes have been o The SMP2 policies for the coastal town will be abandoned. implemented at Ringstead, the Nothe cells involved, especially in the first (Weymouth), , , epoch (today until 2030) and . Flood protection o Urgency of work schemes have been built at Chiswell and o Shortfall in standard of protection Preston. Future schemes are currently (as defined by the Environment being appraised for Lyme Regis (Church Agency) Cliff and East Cliff), and West Bay. o The cost / benefits ratio At Chiswell, on Portland, the EA has put in Dorset’s coastal defences place a major flood defence scheme and The locations (where significant coastal maintains an advanced flood warning defences exist) reflect the geographical system for all local residents. They are extent of property along Dorset’s coast. seeking to further improve the The coastlines of urban Christchurch, effectiveness of the early warning system. , Poole, , Weymouth and Lyme Regis are almost Coast Protection: the historical legal entirely defended against erosion and Newtons Cove Sea Defence. Copyright: perspective Dorset Coast Forum flooding. There are sea-walls, artificial shingle banks and beaches retained by In and Wales, there is an historic Developments along the majority of the groynes. Solid walls can provide important common law duty on the Crown to protect Dorset coast is light, and open coast extra amenities such as level promenades. the coast (from loss) and this duty may be sections remain without man-made Such defences are usually well passed down to an appointed statutory defences. It is therefore the smaller established, but their use is more body. The right for landowners to protect coastal towns and villages which are most questionable now than in the past. The their property is a longstanding legal at risk from loss. Example include: Lyme cost / benefit of hard defences have to be principle. However, such individuals do not Regis, Seatown, West Bay, Portland and carefully calculated and the long-term have to exercise these rights and Swanage. At these there is a considerable sustainability of such structures is suspect landowners constructing sea-walls for their amount of property and infrastructure because there is usually a continual own benefit are not obliged to maintain threatened by landsliding. Towns more 3

Dorset Marine and Coastal Topic Paper Series 2010 Coastal Defence

these to protect others. Recent case law 2003. The aim is to ensure a better managing flood defences both inland as has further established that an occupier of quality of water within lakes, streams well as on the coast. This approach gives coastal land owes a measured duty of and rivers but also includes estuaries the EA a ‘gatekeeper’ role as compared to care at common law in this respect. Other and coastal waters (out to 1 mile from the previous arrangements whereby permissions such as planning permission low water). Plans for coastal defences grants were made by Defra directly to the and consent in relation to any are assessed against their likely Local Authority. environmental designations would impact upon water quality. normally be required before individuals • River Basin Management Plans (under • The Coast Protection Act, 1949 can commence with private defence the WFD) have to drawn up for every provides an integrated approach to works. river basin district in England and coast protection works. This embodies Wales. Coastal defences are deemed any construction, alteration, to be those that reach the tidal limit of demolition, modifications and repairs Sources of Coastal and Environmental a river or estuary and so are subject to for the purpose for protecting land from Law the controls set out in the WFD. erosion or encroachment by the sea. o International treaties (e.g. Law of Coincidentally, the same criteria are The power to undertake coastal the Sea) now used for defining the boundaries defence projects is vested in the o EU Legislation for Shoreline Management Plan (SMP) relevant Coast Protection Authority. o UK Primary legislation (Acts and coastal cells. Their functions are confined to the Statutes) open coast. The Act provides only o UK Secondary legislation • The Habitats (92/43/EEC) and Birds enabling legislation and does not set (Statutory Instruments) (79/409/EEC) Directives have down a duty upon the authority to o Case law implications for coastal defence protect. The Act does however, o Departmental notes (Planning management where protection of the provide for the compulsory purchasing Policy Statements etc coast may be restricted because of land where works or repairs are o Government Circulars, Codes of designations under these directives proposed. Section 34 of the Act was Practice may preclude the building of protection modified to extend its scope to include o Bye-Laws structures. provisions for an assessment of the environmental impacts of any The Regulations & Regulators National proposed works. The Act also The Environment Agency (since 2008) indicates that County Authorities do Europe has been the national lead agency on have some obligation to contribute to • The European Water Framework coast defence policy, and provides the coastal defence capital works but they Directive (2000/60/EC) (WFD) majority of funding through grant aid for rarely do. became part of UK law in December schemes. It is also responsible for 4

Dorset Marine and Coastal Topic Paper Series 2010 Coastal Defence

Planning permission will always be risks of flooding, erosion and land policies regarding developments required for any new coast protection instability, as well as coastal protection where flooding is a measurable risk. It works and to modify existing structures. and defence. It outlines policies for requires that flood risk is fully The Local Authority will need to determine developments which may specifically considered at all stages in the planning whether an Environmental Impact require a coastal location, including process and to generally direct Assessment (sic) is also necessary. tourism, recreation, mineral extraction, developments away from areas at energy generation and wastewater and highest risk. PPS 25 makes clear that • FEPA Licences (Food and sewage treatment plants. In mid-2009, the EA has the lead role in giving Environmental Protection Act (1985) the Department for Communities and advice on flooding matters at the A licence will be required if any part of Local Government indicated that there strategic level and for all planning a proposed construction will be was a need to update existing policy in applications. submerged at Mean High Water the light of better data regarding Spring (MHWS) tides. Construction climate change and sea level rise. • The Water Resources Act (1991) includes not only materials used during Revisions are likely to suggest that: and the Land Drainage Act (1991, construction of, for example, new o Modest developments (of a time- amended 1994) provide the primary harbour walls, offshore structures, limited nature) should be allowed in enabling legislation for sea defence pontoons, jetties, land reclamation or vulnerable coastal locations (e.g. works aimed at the prevention of private sea-walls but also their use in facilities for tourism such as cafés flooding. It also provides for the 'soft-engineered' sea defences, such etc) and that the original construction of drainage works for “the as beach nourishment, and associated presumption not to allow defence against sea water and tidal groynes and revetments. Such developments in such areas (as laid water.” The Water Resources Act licences are currently issued by the down in PPG20) should be (2003) adds important details Marine and Fisheries Agency (the rescinded regarding the funding for new flood MFA) but this power transfered to the o Specific coastal change defence works. Marine Management Organisation (the management areas (CCMA’s) be MMO) in the summer of 2010. identified for those locations that are • Land Drainage Act, 1991. Local particularly likely to be affected by a Authorities have the power to carry out • PPG 20 (Coastal Planning) planning rise in sea level or an accelerated works to improve safety and flood guidance document has been rate of coastal erosion control improvements along waterways superceded. It covered the character o The new policy statement will form and on the coast, but are also required of the coast, designated areas and an Annexe to PPS25 to ensure that the works do not hinder heritage coasts. It discusses types of navigation, obstruct channels or coasts, policies for their conservation • PPS25 (Development and Flood significantly damage habitats or other and development and policies covering Risk) explains the Government’s 5

Dorset Marine and Coastal Topic Paper Series 2010 Coastal Defence

aspects of the environment (such as lead role in developing Shoreline The Policy Base historical settings etc). Management Plans and other Strategy The Environment Agency has overall Plans. They are also responsible for responsibility for policy development and • Coastal Habitat Management Plans producing and implementing planning flood defence and coast protection in (ChaMP’s). These plans consider the policies through the local plans. England and Wales. They can dispense long-term cumulative impacts of flood grant aid for new defence schemes and and coastal defence schemes in • Beach Management Plans (non- would oversee the implementation. The relation to habitats and the impacts of statutory) are often commissioned by EA can provide grants for defence climate change. ChaMPs can also District Authorities to manage coastal structures, but not for associated land recommend modifications to a defence areas and produced by local instability works which are frequently scheme to help minimise habitat loss authorities and the Environment required to complete a successful coastal and to identify where habitat agency defence project. The Department for restoration is feasible. Information Communities and Local Government derived from these sources can all be • The Regional Strategic Monitoring (DCLG) have this power though it is rarely fed into the SMP review process. Programmes (conducted by the exercised. The basis for national (England Channel Coast Observatory in the and Wales) policy for coast defence was South and West) provide the data for originally embodied in the EA Strategy for County SMPs and other coastal defence work. Flood and Coastal Defence , published in • The County Structure Plan has a Digital ground modelling is used to 1993. The core aims (for coast defences) statutory role in setting over-arching determine beach volume changes and are outlined as: planning policies for Dorset, including the resulting data can be used to those influencing the pattern of identify and quantify areas of erosion • Environmentally acceptable: natural development and environmental and accretion. processes should not be disrupted protection. There is also a except where life or important man- responsibility to support and uphold • Water Level Management Plans. made or natural assets are at risk. such items as the EU Water Especially important in estuarine Framework Directive, Shoreline floodplain locations such as Radipole • Technically sound: a range of Management Plans and AONB on the River Wey at Weymouth options should be considered, and Management Plans. schemes should be sustainable and • The Parish Council would normally work with natural processes as far as • Coast Protection Authorities be consulted on coast defence possible. (Coastal District/Unitary Councils) plans/schemes relating to their parish. have a statutory lead responsibility for • Economically viable: the benefits of coast protection including having a defending must be equal to or exceed 6

Dorset Marine and Coastal Topic Paper Series 2010 Coastal Defence

the costs. The Environment Agency the next 100 years. The first iteration of the coast can provide the sediment which will undertake a series of financial Shoreline Management Plans for England forms beaches elsewhere. On Dorset’s tests during the planning phase of a and Wales was carried out in the late rural coast the issue of coastal defence is new project and a cost / benefit ratio of 1990’s (SMP1). The second iteration also set within long-term conservation 1:5 is considered reasonable before began in 2008 and completion of all SMP objectives. In particular there is a need to approval can be granted. reviews is scheduled for 2010 (SMP2). In protect the natural processes that both a number of cases coastal cell boundaries underpin the coast’s internationally Environmental Impact Assessments have been altered since round one. The important geomorphology and to maintain (EIA) and ‘Appropriate Assessments’ other distinct difference of note is that the the exposures of Triassic, Jurassic and Coast Protection works (other than plans have to extend up to all tidal limits Cretaceous geology which form the basis maintenance or refurbishments) fall within within rivers and estuaries; this was not of the UNESCO World Heritage Schedule 2 of the Town and Country the case with SMP 1. designation awarded in December 2001, Planning Regulations (1999) and may (in and also the post-Cretacaeous strata advance of any works) require an EIA to The four main options available for any which form the cliffs east from to be carried out. This is most probable if the given coastal cell are: Chewton Bunny. site of any proposed works is • Advance the existing defence line environmentally sensitive. If the location is • Managed realignment (either of Two SMP2 documents cover the Dorset a ‘Natura 2000’ site designated under the existing defence measures or by coast: European Habitats Directive (1994), then managing and manipulating natural an ‘Appropriate Assessment’ must also be processes • Hurst Spit to Durlston. The Two Bays carried out. • No active intervention (meaning that SMP no financial obligations are intended) • Durlston-Rame Head. Plymouth. Flood risk may also be a material • Hold the line (where existing (South and Dorset SMP) consideration for certain developments for measures to defend the coast and which an EIA will be required especially if property are to be continued and The lead authority for the Two Bays SMP the impact of development on flood risk is maintained) is Bournemouth Unitary Authority and for likely to affect a designated conservation the South Devon and Dorset SMP, it is site or compromise the SMP-preferred The review process recognises that Teignbridge District Council. option for a given cell. coastal defence works need to be conceived in a way that takes due regard The EA have indicated that a further level Shoreline Management Plans (SMPs) for the natural processes operating at sea of more detailed ‘Strategy Plans’ may be SMPs are high level strategic documents and on the coast. These processes can required for some sections of the coast in that set the framework for the way that operate over large stretches of coastline, the future. These aim to ensure more coast defence matters are managed for for example eroding cliffs on one part of detailed strategic consideration of the 7

Dorset Marine and Coastal Topic Paper Series 2010 Coastal Defence

long-term and knock-on effects of Effective coastal defence relies on the and is hosted by New Forest District proposed schemes, and to ensure related coastal authorities having access to good Council, in partnership with the University schemes are tackled in an integrated way. quality information about the development of and the National and use of the coast, and a good scientific Oceanography Centre, Southampton. The Planning Issues understanding of the coastal processes Data Catalogue is a searchable database The justification to defend a section of which are operating. Achieving this is a of coastal data (bathymetric, beach coast is generally determined by the considerable and continuing task. The profiles, aerial photographs, LIDAR, etc) presence or absence of valued structures Shoreline Management Plans assist by collected by the Strategic Regional and infrastructure. Thus the planning collating available information and Coastal Monitoring Programmes. Data are system has an important long-term role to informing communities and planners of freely available for download. play. Land-use plans need to ensure that specific issues at specific locations along inappropriate development does not take the coast. place where it would increase the risk to other properties or cause erosional There is a growing need for the coast Coastal Partnerships problems further along the coast. protection authorities to hold and manage Coastal Partnerships, including the Dorset This position is supported by Government the data being produced and to co- Coast Forum, involve people with diverse planning guidance and Environment ordinate their efforts to avoid duplicating skills and interests but all with a keen Agency policies for protecting flood plains, effort. Much of the information being interest and concern for the coast. and by the Dorset Structure Plan. gathered is potentially relevant to wider Members of local communities, clubs and interests than coastal defence authorities, user groups to local authorities, statutory Construction of coastal defences normally such as coastal planning, emergency agencies, industries, businesses, water requires planning permission and may planning, tourism development, leisure companies, port & harbour authorities and also require a Food and Environmental pursuits, pollution control, nature NGOs are all likely to be in membership. Protection Act (FEPA) licence. conservation and geological interpretation. The general working principles that a Constructions may also require permission The role of computer-based geographical coastal partnership would adopt include: under the Coast Protection Act (1949). information systems (GIS) is of increasing The statutory Local Plans need to provide value, sophistication and importance. • Impartiality and a proven role in and implement policies to restrict conflict resolution and consensus inappropriate defence schemes, ensure The research work carried out by the building quality of schemes when implemented and Channel Coast Observatory (CCO) and • The ability to work across sectors and provide for access to maintain defences. the Plymouth Coastal Observatory (PCO) between all levels of decision-making is of great value in this context. The CCO • Raising awareness of issues and a The Information Base is the data management centre for the mechanism for community Regional Coastal Monitoring Programmes engagement 8

Dorset Marine and Coastal Topic Paper Series 2010 Coastal Defence

• Horizon scanning to inform SCOPAC (Standing Conference on threats posed by sea level rise and /or organisations of coastal issues Problems Associated with the Coast) erosion. The Dorset and • Attracting project funding and initiating SCOPAC was inaugurated in 1986 to Pathfinder examined the issues at collaborative ventures facilitate co-ordination and joint research Swanage, Ringstead, Preston, Seatown, • Providing a gateway service and ‘one- between coastal operating authorities from Charmouth, and in detail. stop-shop’ for information, contacts to West Sussex. The core and project report production aim of the group is to provide a strong High Quality Defence Schemes • Filling gaps where there are no political forum for these authorities and This stage is reached when it is judged sectoral responsibilities and mobilising other organisations that have a that a replacement or extension to existing voluntary support and involvement responsibility and interest in coastal risk defences is essential. Dorset’s coast can • Providing a (bottom-up) conduit to management. The group also assists demonstrate several schemes, which regional and national government coastal stakeholders by disseminating exemplify good practice in design and advice and good practice through the implementation, including the Lyme Regis Partnership approaches have been tried publication of advice and guidance, the Phase 1-3 coast protection works and tested in many fields and are holding of conferences, field meetings and constructed between 1995 and 2004, becoming increasingly popular. Coastal events. which has attracted national awards. partnerships specialise in providing Since 1997, other significant and services to help organisations deliver The full conference meets regularly, and is successful projects have been carried out Integrated Coastal Zone Management supported by an officers’ working group, at Charmouth, and (ICZM). There are other organisations and and a research sub-group. SCOPAC has Preston Beach. some partnership initiatives that deliver commissioned or supported a range of ICZM (e.g. AONB’s with sections of coast, valuable research projects on behalf of its The 2001 award by UNESCO of World the European Marine Sites and Shoreline members since its formation. The value in Heritage Status for the Dorset and East Management Groups) but they don’t offer working jointly with other professionals has Devon coast has added a new constraint the same core services which the existing been recognised by Dorset’s coastal to the planning and construction of new voluntary arrangements provide. Coastal engineers for many years. defence schemes. WH status is now a Partnerships are thus at the forefront of material consideration when new schemes providing mechanisms to help deliver Defra ‘Coastal Pathfinder’ Projects are being evaluated. ICZM. This is a series of highly focussed projects (to be completed by Spring 2011) that There are also some schemes, which Groups/Projects associated with looks at the issues surrounding coastal have damaged the quality of the coast. coastal defence loss, coastal ‘squeeze’ and the Well-designed coastal defences have the development of tools necessary to help potential to create and protect wildlife local coastal communities to adapt to the resources, as well as providing access, 9

Dorset Marine and Coastal Topic Paper Series 2010 Coastal Defence

securing coastal paths and providing other from offshore dredging areas although property will become subject to flood and amenity benefits. Schemes need to be quarried material can also be used. erosional risk. Whilst most urban coastline increasingly sensitive to the ecological and Material sourced from dredged navigation will continue to be defended, there are landscape aspects of the coast, and channels (e.g. from ) has likely to be some places where property should seek to enhance these features. been used to recharge beaches at could not be defended without unjustifiable Finally schemes need to be properly Bournemouth, and Swanage. costs or environmental damage. maintained and monitored after they have been built. Generally, new schemes have Soft coast defence techniques have the Such situations must be handled with a design life of some 60-70 years and benefit of conserving sediments for great sensitivity. Acceptable solutions for funds need to be allocated towards defence use rather than erecting solid the owners affected will be difficult. The ongoing maintenance. Increasingly, linear barriers along the shoreline. review of the Shoreline Management considerations have to be given to However, groynes are often required to Plans (SMP2) provides a suitable preparing ‘exit strategies’ that can be Beach repl opportunity to consider these issues in implemented at the end of the design life stabilise the recharge material and to detail and to communicate directly with period. prevent drift. In recent years, the those communities likely to be affected. sustainability of soft engineering schemes The DEFRA ‘Coastal Pathfinder’ and C- ‘Soft’ Coastal Defences has been brought into question. Typically, SCOPE research projects offer similar Natural features already provide coastal beach recharge schemes have to be opportunities. defence capacity over large parts of the repeated (or at least replenished) every 4- Dorset Coast. and Studland 10 years. The current direction for coastal defence Dunes are two examples of large features policies is to move away from the use of which protect the land behind them from ‘hard defences’ (concrete, metal, stone erosion and flooding and elsewhere Sea-Level Rise: current research etc), but to use natural processes smaller beaches provide some measure of Coastal sea levels in the western counties wherever possible to reduce flood risk. natural protection. There is a growing of Britain have been rising at Throughout England and Wales there are recognition of the value of natural coastal approximately 2.5mm per year during the some 24,000 miles of flood defences. In defences and of the need to work with and 20th century but this rate is now 2010/11, the EA plan to spend £161 protect natural processes. accelerating rapidly. Predictions for the million maintaining existing flood defences next 100 years suggest a rate of up to 1cm and £270 million building new and Soft engineering techniques typically per annum (averaged over the whole improved ones. involve the use of sand, shingle or larger period). It is also likely that the frequency aggregates to replenish beach sediments. of extreme storm events will also increase. Contribution to Paper: Tony Flux The materials used are typically imported In the long-term, an increasing amount of

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