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Rivers Arun to Adur flood and erosion management strategy 2010 - 2020

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introduction

The Environment Agency, Arun District Council, Worthing Borough Council and Adur District Council in partnership have undertaken a review of how we manage the coastline between the River Arun and the River Adur, refer to Figure 1 for plan. The final River Arun to Adur Flood and Erosion Management Strategy sets out our plan to manage flood and erosion risks along this coastline. The final strategy was approved (April 2010) by the Environment Agency and Arun District, Worthing Borough and Adur District Councils. Through this management strategy, the partnership has identified ways to protect 9,800 properties that are at risk of flooding and erosion over the next 100 years. We plan to sustain or improve all of the defences between the River Arun and the River Adur, except for a small section of the River Adur east bank where we are investigating the potential to create some new intertidal habitat. We have already started to work on a number of the projects following on from the decisions made in this strategy. This strategy takes into account:

• a predicted increase in sea level rise due to climate change; • the need to evaluate options over the long term; • the impacts of implementation on the natural environment; • the Beachy Head to Selsey Bill Shoreline Management Plan; • the 120 responses to our public consultation carried out in 2008.

Our final strategy incorporates information and comments provided during that time. Comments from local communities were generally supportive of the proposed option for each frontage, although there were some concerns regarding the drainage of Ferring Rife and availability of funding for the works. Views from Natural England and English Heritage on how our strategy impacts the natural environment and archaeology in the area have also been taken into account during the development of the strategy and both support our approved options.

East End of Shoreham Beach

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This strategy covers the coastline between the River Arun at Littlehampton and the River Adur at Shoreham. This stretch of coast is characterised by shingle beaches, with a relatively low-lying coastal plain behind. The area includes large residential and commercial developments as well as important local infrastructure, such as roads and railway lines. At present the number of properties at risk of a 1:200 year flooding event is about 1,500. This is predicted to increase to about 7,600 over the next 100 years due to sea level rise, with an additional 2,200 properties at risk from coastal erosion. This strategy covers a number of areas that are environmentally important. The Adur Estuary Site of Special Scientific Interest (SSSI), which also includes a reserve managed by the Royal Society for the Protection of Birds (RSPB), is a nationally important site. Sites of regional importance include Shoreham Beach Site of Nature Conservation Interest (SNCI) and Local Nature Reserve (LNR), Widewater Lagoon SNCI and LNR and Ferring Rife SNCI. Rising sea levels could result in loss of saltmarsh habitat over the 100 year lifetime of the strategy. We are looking at sites locally that may be used to create replacement habitat. Work is currently underway investigating the potential for creating mudflat and saltmarsh, floodplain grassland and reedbed habitat at upstream sites on the River Adur, and mudflat and saltmarsh habitat on the east bank of the River Arun.

strategy area

River Adur

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Figure 1: Rivers Arun to Adur Strategy map

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who is involved in managing this coastline?

The Operating Authorities for managing flood and erosion risk for the coastline between the Rivers Arun and Adur are the Environment Agency, Arun District Council, Worthing Borough Council and Adur District Council. As Operating Authorities, we have permissive powers that allow us to protect both people and property where economically, technically and environmentally viable and where affordable within national budgets. Generally we have no legal duty on us to build and maintain coastal defences. In April 2008, the Environment Agency became responsible for overseeing the management of all flood and coastal erosion risk in England. Under the new arrangements the Environment Agency now:

• takes the lead for managing coastal flooding risk in England; • ensures that sustainable long-term Shoreline Management Plans are in place for our coastline and

approves them on behalf of Department for the Environment, Food and Rural Affairs (Defra). This coastline is covered by the Beachy Head to Selsey Bill Shoreline Management Plan;

• allocates flood and coastal erosion risk management capital funding. Under current policies the local authorities will continue to deliver their coastal erosion role as before, but now under the Environment Agency’s overarching management. The Environment Agency and local authorities are working hard to ensure that we deliver this new way of working in a true partnership approach. We work with other organisations, such as Natural England, to understand what effect our strategy will have on the local environment.

Lancing Beach

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strategy development

For each frontage we have assessed flood and erosion risk management options, using technical, economic, social and environmental criteria. For each option we have considered:

• how it would address flood and erosion risk to people and properties; • whether it would work for the short, medium or long term given the effect of sea level rise; • the cost of the option and the value of damage avoided by providing such defences; • how it would be built or maintained; • how it would impact on people who live in, work in and visit the area; • the effect it would have on the natural environment.

Management Option

Description

No active intervention

Let nature take its course – no work will be carried out to maintain or repair defences, allowing them to deteriorate over time.

Active intervention to hold the line – by maintain, sustain or improve

Maintain – defences are maintained as they are but as sea levels rise, flood and erosion risk increases over time. Sustain – defences are raised and strengthened keeping the levels of flood and erosion risk the same as now. Improve – defences are improved to increase the standard of protection over time, beyond the requirements of rising sea levels.

Managed realignment

Improve coastal stability by managing and moving coastal defences to a more sustainable location further inland.

Adaptive management

Managing complex areas by monitoring changes and acting on them in a planned but flexible way, increasing our understanding over time.

Our final option for each of the frontages is generally to hold the line by improving or sustaining the current standard of defence against flood and erosion. The options were finalised after widespread consultation and review by local authorities, the Environment Agency and Defra. Now that they are approved, the schemes will need to qualify for national funding. They will be ranked against other nationally submitted proposals for flood and erosion risk management and funding will be allocated on a priority basis. We want communities to help in the design of flood risk management schemes to maximise the local benefits and we will seek feedback again when we are in a position to develop the options further.

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what we plan to do – river frontages

Implementation Plan

Frontage Approved strategy option

Planned work (subject to funding) Date

Raise defences where required 2010 – 2014* River Arun East Bank Hold the line –

Improve Replace steel sheet piling at end of residual life 2060

Raise defences of west bank tidal walls where required 2014*

Habitat creation works 2016

Raise sections of wall not requiring raising in year two 2031 and 2036

River Adur West Bank Hold the line – Improve

Tidal barrier (or further defence raising) 2060+

Raise Defences 2030 Hold the line – Improve (north) Tidal barrier (or further defence

raising) 2060+

Raise defences 2020 Hold the line – Sustain (central)

Raise defences 2060

River Adur East Bank

No active intervention (east) n/a n/a

*These schemes are in the Environment Agency’s Medium Term Plan (five year programme of Flood and Coastal Erosion Schemes 2010/2011 -2014/2015), published in April 2010. For these schemes we will produce a Project Appraisal Report which will look in detail at the costs and benefits and how to protect as many properties as we can economically justify. It will determine what materials to build any new defences from, what they will look like, the exact alignment and how high they need to be. This strategy does not guarantee funding for these planned works. Please see page 14 to read about how funding is allocated.

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Frontage Approved strategy option Planned work (subject to funding) Date

Beach nourishment, groynes and some sea wall improvements where required. (Littlehampton)

2045

Beach nourishment and sea wall construction

2025 Littlehampton to Rustington Hold the line – Improve

Replace groynes at end of residual life 2060

Rustington to Goring Hold the line – Sustain

Replace groynes at end of residual life; Further groyne replacement and beach nourishment, construction of sea wall

2016 2060

Replace all groynes at end of residual life; 2035

Ferring Rife Hold the line – Sustain Beach nourishment 2060

Replace groynes at end of residual life 2021 – 2025 Marine

Crescent, Goring

Hold the line – Sustain Beach nourishment 2060

Replace groynes at end of residual life (phased with five yearly intervals)

2016 – 2045 Worthing Hold the line – Sustain

Beach nourishment 2085

Brooklands to Shoreham Hold the line – Sustain Beach nourishment and rebuild

timber breastwork 2060

what we plan to do – coastal frontages

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River Arun East Bank

Littlehampton is a coastal town at the mouth of the River Arun with most of the town built on the East Bank. It is a busy seaside resort and a local commercial centre. There are a number of flood defences along the east bank of the river including earth embankments, sheet piled walls and a concrete apron with brick wall. The Environment Agency maintains some of the defences but the majority are privately owned, with Littlehampton Harbour Board also responsible for a significant frontage. As the majority of the defences currently provide a low standard of protection, they can expect to be overtopped with increasing frequency which may eventually lead to failure and flooding as sea level rises. River Arun West Bank is considered in the River Arun to Pagham Flood and Erosion Risk Management Strategy which can be viewed on the Environment Agency website.

Between Littlehampton and Rustington is East Beach, a sand and shingle beach frontage. There are significant residential and commercial properties immediately behind the beach and promenade. The coastline is protected by a range of defences including a low concrete seawall and a shingle bank with timber groynes. The groynes immediately adjacent to the river have reached the end of their life. However, they will not be replaced immediately as the beach and sea wall currently provide an acceptable defence.

Approved Strategy Option – Hold the Line - Improve Improve the current defences through beach nourishment, replacement of groynes at the end of their residual life (see table on previous page for timings) and reconstruction of the concrete wall, to increase protection to Littlehampton.

Approved Strategy Option Hold the line - Improve Improve the current standard of protection by raising the level of the walls and embankments immediately. Replace the steel sheet piling at the end of its residual life, in approximately 50 years.

Littlehampton to Rustington

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Approved Strategy Option – Hold the line - Sustain Sustain the current standard of protection by raising defences over time as sea level rises. Replace the groynes at the end of their residual life (in approximately five years), with further groyne replacement, beach nourishment and the construction of a sea wall in approximately 50 years.

Ferring Rife

This frontage includes the residential areas of East Preston, Kingston and Ferring and the large area of open space and agricultural land around Kingston Gorse. The urban areas are immediately behind a low vegetated bank at the back of the beach. The primary defence is the shingle beach with a number of timber and rock groynes, maintained by Arun District Council and Worthing Borough Council. They currently provide an acceptable standard of protection to this area and will not require major investment in the immediate future.

Ferring Rife is in the low-lying area in South Ferring. It is a wide channel between two grassy embankments which flows beneath a beachfront car park to a sea outfall. Immediately adjacent to the channel are the residential properties of Ferring. The primary defence is a timber wall protected by a wide shingle beach. The defences are maintained by the Environment Agency and they currently provide an acceptable standard of protection. Approved Strategy Option

Hold the line - Sustain Sustain the current standard of protection by raising defences over time as sea level rises. This will require maintenance of existing groynes, and replacement at the end of their residual life in approximately 25 years, as well as beach nourishment.

Rustington to Goring (excluding Ferring Rife)

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This frontage runs from the west end of Marine Crescent in Goring to the western suburbs of Worthing and consists of mainly residential properties. This beach is a major local attraction for fishing, sailing, jet skiing and kite surfing. Between the beach and Marine Crescent is open space, beachfront parking and a yacht club. The primary defence is the shingle beach which is held in place by timber and rock groynes. Particularly vulnerable areas are protected against erosion and flooding by rock armouring and splash walls. The defences are maintained by Worthing Borough Council and currently provide an acceptable standard of protection to this area.

Worthing is a town with a large population and busy commercial centre. A wide promenade stretches along the coast with a pier near the town centre and theatres and restaurants nearby. The primary defence between West Parade and Brooklands Pleasure Park is a shingle beach held in place by timber and rock groynes. Particularly vulnerable areas are protected against erosion and flooding by rock armouring and sea walls. The defences are maintained by Worthing Borough Council and they currently provide an acceptable standard of protection to the town.

Approved Strategy Option – Hold the line - Sustain Sustain the current standard of protection by raising the defences over time as sea level rises. This will require replacement of groynes at the end of their residual life, in approximately 11 to 15 years, and beach nourishment.

Approved Strategy Option – Hold the line - Sustain Sustain the current standard of protection by raising these defences over time as sea level rises. This will require ongoing and future works to replace and improve groynes over the next 6 to 35 years, beach nourishment, protecting vulnerable sections of the defences from erosion.

Marine Crescent, Goring

Worthing

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This frontage protects residential properties with some commercial and industrial properties. It includes the Brooklands Pleasure Park, Widewater Lagoon and Shoreham Beach. The primary defence between Brooklands Pleasure Park and the mouth of the River Adur is a concrete sea wall with some timber sections, protected by a shingle beach held in place by timber and rock groynes. The beach and groynes are maintained by the Environment Agency and have recently been improved to provide an acceptable standard of protection to the local communities. Parts of this frontage are vulnerable to flooding from the west bank of the River Adur. Please see page 13 for our proposals for this frontage.

Approved Strategy Options - Hold the line - Sustain Sustain the current standard of protection by improving the defences as sea level rises. This will require beach management and maintenance of the existing groynes and rebuilding of the timber breastwork in approximately 50 years.

Brooklands to Shoreham By Sea

River Adur

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River Adur This frontage includes the east and west banks of the River Adur from the A27 southwards. The west bank is one frontage from the A27 to the river mouth. The east bank has been divided into three sections:

• north section, A27 to footbridge; • central section, footbridge to Kingston Beach lighthouse; • east section, Kingston Beach lighthouse to the lock gates (does not include Shoreham Port).

Along the River Adur there are significant areas of residential and commercial property, many historic and modern buildings, as well as public open space and agricultural land. The north section of the east bank includes the urban area of the town and the central and eastern sections feature mainly light commercial and leisure properties and the Port facilities. Shoreham airport and the houseboat community are on the west bank. The banks of the River Adur include a variety of defence types including steel sheet piling, concrete walls, rock revetments and timber groynes. The defences on the west bank are mostly maintained by the Environment Agency and provide a very low standard of protection with the possibility of regular overtopping and defence failure. The river, from the footbridge to upstream of the A27 is designated as a Site of Special Scientific Interest (SSSI); there is also an RSPB reserve to the west of the footbridge. To keep pace with predicted sea level rise, defences would need to be raised by up to 1.5m in some places over the 100 year strategy period. An adaptive approach is therefore proposed with defence raising over the first 50 years of the strategy period. Sea level rise beyond that time would be addressed by either further defence raising or by giving consideration to the construction of a tidal barrier in the latter half of the strategy. This approach will be kept under review as sea level rise predictions are confirmed or amended.

Approved Strategy Options Improve the defences on the west bank and east bank (north section only) to provide a higher standard of protection. Sustain the east bank, central section, by raising the existing defences to take account of sea level rise while providing the same standard of protection. There will be no active intervention for the east bank, east section, due to the current low flood risk in this area.

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Implementing this flood and erosion risk management strategy depends on the availability of funding from central government. Funding is allocated nationally and priority given to schemes protecting large numbers of houses, where flooding and erosion are an immediate risk and likely to cause significant damage. In this document, we set out how we intend to manage flood and erosion risk over the next 100 years. In these cases, exposure to flood or erosion risk could increase over time in the absence of investment. To help us to do more to manage flood and coastal erosion risks we will look for contributions from private, public or voluntary organisations or communities who will benefit the most from our work. By reducing our costs, a contribution will help to improve the chances of the work happening at an earlier date than would otherwise have been possible. In addition, a contribution could fund additional work to increase the standard of protection over those which we would otherwise have delivered. Sources of contributions may include infrastructure levies, Section 106 funding under the Town and Planning Act (1990) and precepts at parish council level, as well as contributions from local commercial interests which would benefit directly from a reduction in flood risk.

funding for flood and erosion risk management

Worthing Beach

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This final strategy and the Strategic Environmental Assessment Post Adoption Statement were published in November 2010 and can be downloaded from the Environment Agency website. www.environment-agency.gov.uk/yourenv/consultations/ You can keep up to date with the Environment Agency's progress on implementing this strategy on our website: www.environment-agency.gov.uk/homeandleisure/floods and clicking on “flood schemes and strategies in your area”. You can also access these documents and find out about progress on implementing the strategy from the partners websites: www.arun.gov.uk and follow the links to Engineers (under the A to Z of services) and then Coast Protection www.worthing.gov.uk www.adur.gov.uk

where can I find out more?

River Arun (north of the A259 bridge)

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Would you like to find out more about the Environment Agency? Then call us on 08708 506 506 (Mon – Fri 8-6) email enquiries@environment-agency.gov.uk or visit our website www.environment-agency.gov.uk incident hotline 0800 80 70 60 (24 hrs) floodline 0845 988 1188 Would you like to find out more about Arun District Council? Then call us on 01903 737500 email info@arun.gov.uk or visit our website www.arun.gov.uk

Would you like to find out more about Adur District Council? Then call us on 01273 263000 email info@adur.gov.uk or visit our website www.adur.gov.uk

Would you like to find out more about Worthing Borough Council? Then call us on 01903 239999 email enquiries@worthing.gov.uk or visit our website www.worthing.gov.uk