Planning for the Future River Wey Flood Risk Management Draft Strategy 2010 Public Consultation Document We Are the Environment Agency

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planning for the future River Wey Flood Risk Management Draft Strategy 2010 Public consultation document 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.

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Environment Agency Swift House Frimley Business Park Frimley GU16 7SQ Tel: 08708 506506 Email: [email protected] www.environment-agency.gov.uk

This consultation document summarises the work carried out to investigate and manage strategic flood risk in the River Wey catchment. Our preferred option is to maintain the river system and structures to meet existing flood risk standards. These standards will decrease with time due to climate change. Flood risk is the combination of probability (likelihood) and consequence (impact). We will reduce the impacts of flooding by: enhancing our flood warning and forecasting ability, influencing development planning and promoting flood proofing measures in homes. In this document the River Wey catchment has been divided in to five areas known as ‘reaches’ these are shown on Map 1.

Map 1 Wey Catchment Overall Map – 5 Reaches

Reach 5

Reach 4

Reach 3

Reach 1 Reach 2

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 1 Contents

Chapter 1 Introduction 3 Chapter 2 The River Wey 5 Chapter 3 Existing flood risk and strategic options 7 Chapter 4 Options considered and their effects 11 Reach 1: Alton/Haslemere to Tilford 12 Reach 2: Tilford to Shalford 14 Reach 3: Shalford to Send 16 Reach 4: Send to Wisley 18 Reach 5: Wisley to Weybridge 20 Chapter 5 The strategy plan 22

2 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 1.0

We are developing a strategy for managing the risk of flooding from rivers within the River Wey catchment in response to past flooding in the urban centres of: Farnham, Godalming, Guildford, Old Woking, Weybridge and Byfleet.

Introduction

This draft strategy sets out our plan for sustainable The Wey and Godalming Navigations were created flood risk management to people, property and the under Acts of Parliament and make the River environment over the next 100 years. Wey navigable from the Thames at Weybridge to Town Wharf, Godalming. This involved creation of We are able to look at flood risk management in locks, weirs, and in places, shorter channels. The a comprehensive way, by considering associated navigations were donated to the National Trust and impacts and interests of other parties. are now owned and operated by the National Trust to This strategy looks at the key issues we need to maintain navigation and channel depths. address. It outlines the options explored and details the preferred options. We have done a lot of work to Between 1930 and 1935 Surrey County Council come up with our recommendations but these are carried out the River Wey Improvement Scheme not yet finalised. You can find out how to send us (RWIS) to increase the flood flow capacity of the your comments on page 25. river whilst maintaining navigation depth. This involved removal of meanders, increasing channel This strategy will help to put into practice the Thames capacity and 14 new weirs between Godalming Catchment Flood Management Plan, which sets and Weybridge. A statutory agreement with the the strategic policies for flood risk management navigation trustees was made to ensure that the in the region. As well as this strategy, other plans new weirs would not affect navigation by siltation and policies we have developed have identified at ten key sites. Sand is removed at these annually long-term environmental improvement partnership to enable boats to navigate without grounding. opportunities that may also help to reduce flood risk. The RWIS has been handed down through various With predicted global warming and the increased organisations and we now own and are responsible frequency and intensity of storms, our environment is for these structures. We have an agreement with the likely to change. The number of flood risk areas may National Trust to operate these. increase and water shortages and dry periods are The riverside owners of channels and structures have expected to extend. These are all issues that affect a legal duty to pass flood flows, maintain the water the River Wey. levels for navigation and repair structures on the In addition to the flood risks in the catchment area, River Wey. there are many river control structures (weirs and sluices). These are used to maintain minimum water depths for navigation and control flow between the natural river and the navigation channels.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 3 We have permissive powers under the to reduce the likelihood and impacts of flooding at Water Resources Act 1991, to build flood the key flood risk areas on the River Wey. management structures to protect people and This is a public consultation document and we would property. Where these are economically viable and welcome your comments by Friday 14 May 2010. government funds are available. However, funding is Our contact details are on page 25. limited and competition from other areas in the UK for this money is high. We have investigated options

4 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 2.0

The River Wey is one of the larger rivers that flow into the lower River Thames, draining an area or catchment of 900 square kilometres over a length of 34km (21 miles).

The River Wey

There are about 1050 commercial and residential as in central Guilford, Woking and Byfleet. But properties at risk of flooding in the urban centres for development also presents the opportunity to a one percent annual probability flood event (1 in introduce flood mitigation to reduce the impact. 100 chance of occurring in any year). We have a major role in influencing development to reduce flood risk, and we are working to achieve this. The River Wey begins its journey at Alton (the North Wey) and near Haslemere (the South Wey), these two The Wey is navigable from Godalming to the River rivers combine at Tilford to form the main River Wey. Thames. Water levels, flows and distribution The Wey flows through the main urban centres of: are controlled by weirs along the river. We have Godalming, Guildford, Old Woking, Byfleet and finally produced an investment and maintenance plan through Weybridge and into the River Thames. Other for the weirs installed as part of the River Wey local centres and lower risk flood areas are in: Alton, Improvements Scheme. Farnham, Cranleigh, Rowley, Bramley and Haslemere. This investment and maintenance plan will ensure The river channel in the areas of the Wey and it’s these weirs and channels maintain their target tributaries furthest from the Thames remains mainly condition for the next 100 years. As part of our unaltered with natural earth banks. The floodplain review into the ownership and maintenance of is mostly undeveloped in these areas, except the RWIS weirs, we discussed potential transfer for a few small towns. Within the undeveloped of these to the National Trust. But concluded that floodplain there are important habitats that we aim we remain best placed to continue ownership and to protect and enhance. During summer, low flows maintenance. affect the upper and middle sections, furthest from As part of our review into maintenance activities, the Thames, meaning less water for wildlife and we looked at the existing RWIS agreement and recreation. sediment removal. We concluded that this work is In flood, the river overflows into the extensive natural principally to enable navigation and not to reduce floodplain. The majority of river flooding is shallow, flood risk. We have discussed this with the National slow-moving and mostly affects property in urban Trust who indicated that they are interested in taking areas. There are existing flood defences at Farnham, on responsibility for sand removal legally required Parnell Gardens (Byfleet) and Send Marsh. on the River Wey, as it gives them full control over works affecting their navigation interests. We will Planned developments in urban areas run the exercise our powers to remove sand for flood risk risk of increasing vulnerability to flooding, such management.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 5 Other structures on the river system are owned by The Wey also supports diverse and important the National Trust, private owners or a combination fisheries identified in our Wey Valley Fisheries Action of these. We work in partnership with them to Plan, from trout in the chalk-stream headwaters to maintain and operate these for navigation and high-quality course fisheries in the lower and middle to protect habitat areas sensitive to water level sections of the river. Improved fish passage through changes. Water level management plans have been weirs would help: migration and distribution of eel, developed with Natural England to protect these brown and sea trout, salmon, lamprey and barbel. nationally important habitats. In addition to the important ecological value, the Much of the habitat in the catchment has legal Wey provides a wealth of recreational opportunities. protection with nature conservation designations. There are many sites within the study area that are These include: important for both formal and informal recreation and tourism. Including a number of Rights of Way • Special Areas of Conservation (SAC) – Protected footpaths alongside the river. The river landscape by European Union (EU) Habitat Directive is central to the character of the reaches and also • Special Protection Areas (SPAs) – Protected by enhances urban centres, particularly in Guildford, EU Birds Directive Farnham and Godalming. • Ramsar Sites – Wetland protected in the Ramsar A significant area of the catchment is designated Convention as an area of outstanding natural beauty, or is in green belt. There are also Scheduled Monuments • Sites of Special Scientific Interest (SSSI) – Flora, and registered parks and gardens throughout the fauna, geological or physiographical features catchment. • National Nature Reserves (NNR) and Local Nature Reserves (LNR)

6 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 3.0

Existing flood risk and strategic options Reach 1: Alton/Haslemere to Tilford Reach 4: Send to Wisley Located in the upper Wey, there are two This reach is semi-natural and includes the Hoe watercourses, the North Wey and the South Wey. Stream at Woking, a tributary of the River Wey. This is largely a rural area and the river is mostly We are working with Woking Borough Council in a natural without navigation. A two-stage channel at proposed flood defence scheme which is due to Farnham, constructed in 1975, provides flood relief. begin in 2010. There are no other significant flood Increased flood storage capacity in this reach was defences in this reach. During flood events, the river investigated for local and catchment-wide reduction fills floodplain affecting properties, particularly in in flood risk. Old Woking. A scheme at Send Marsh (on the East Clandon Stream) has been completed by us. Reach 2: Tilford to Shalford Reach 5: Wisley to Weybridge This stretch is semi-natural, and is navigable from Godalming either in the river or along the navigation This stretch of river is semi-natural. The river flows channel. Two tributaries enter the River Wey in this through the centres of Byfleet and Weybridge reach, the Cranleigh Waters and the Tillingbourne. before joining the River Thames and is navigable During higher flow events the floodplain storage throughout. There are no significant or effective flood reduces flood risk. However some properties within defences within this reach. During high flow events this area still flood. There are no significant flood the river uses floodplain to store excess river flows. defences within this reach. Increased flood storage capacity in this reach was investigated for local and Strategic options catchment wide reduction in flood risk. We considered the local and strategic effectiveness (over the whole catchment) of a number of options Reach 3: Shalford to Send as described in table 1. This section of the river flows through Guildford, the county town and the largest urban centre in the catchment; although no significant flood defences exist. The floodplain is limited by development and by the North Downs. The river forms a central part of the character of Guildford.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 7

Table 1 Strategic Options Considered

Do nothing no further maintenance or repair work to the existing river or assets.

Do minimum similar to ‘Do nothing’, with reactive works to river channels and assets undertaken when required.

Maintain maintaining the existing river and assets in their current form

Improve structural flood defences constructed to reduce the risk of flooding

Reduce consequences measures that reduce the damage caused by flooding

The following paragraphs describe the current Within reaches two to five there is normally time to situation and identify where properties will be at give warnings of potential flood events. This warning risk of flooding or where significant environmental time increases significantly in the lower reaches of impacts will occur if no action is taken. Higher flows the catchment. Under the ‘Do Nothing’ scenario flood predicted by climate change will increase flood risk warning would stop, so people would be unaware further. and unprepared for any flood events. If we do nothing, the impacts in reaches two to five are similar. The river channel will become overgrown Reach 2: Tilford to Shalford and silt up, reducing flood capacity, and increasing Typically, the river channel has capacity to contain flood risk to properties. River control structures flood flows up to a 20 percent annual probability would in time collapse, significantly reducing water event (1 in 5 chance of occurring in any year), beyond depths, stopping navigation, and increasing risk which the river generally gradually fills floodplain. of drying out during dry weather. This would cause There are about 125 residential properties at risk significant environmental impacts to protected water of flooding during the one percent annual probability level sensitive areas such as flood meadow, bogs event (1 in 100 chance of occurring in any year), and wet woodland. mainly located in and around the centre of The continued availability of floodplain is critical in Godalming. Typical flooding is less than one metre minimising flood risk throughout the catchment. and slow moving. Under the ‘Do nothing’ scenario an extra 60 properties may be at risk of flooding. Reach 1: Alton/Haslemere to Tilford The engineered channel at Farnham provides Reach 3: Shalford to Send estimated flood relief to around 150 properties Typically, the river contains flood flows up to a 20 from a two percent annual probability event (1 in 50 percent annual probability event (1 in 5 chance of chance of occurring in any year). Elsewhere, the rural occurring in any year) in the rural areas within this nature of the reach has more localised flood risk, so reach. maintenance will be targeted where needed.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 9 Flooding occurs in Guildford when the capacity of the event (1 in 100 chance of occurring in any year). confined river channel is exceeded, causing flood Typical flooding is less than one metre and slow water to flow out of the river and into the town. moving. Under the ‘Do nothing’ scenario the same number of properties have an increased risk of In Guildford, there are about 150 residential flooding. properties and 200 commercial properties at risk of flooding during a one percent annual probability event (1 in 100 chance of occurring in any year). Reach 5: Wisley to Weybridge Under the ‘Do nothing’ scenario an extra 90 Typically the river channel contains flood flows up to properties may be at risk of flooding. a 20 percent annual probability event (1 in 5 chance of occurring in any year), before entering floodplain. Reach 4: Send to Wisley There are about 489 residential properties at risk Typically, the river channel has capacity to contain of flooding during a one percent annual probability flood flows up to a 20 percent annual probability event (1 in 100 chance of occurring in any year). event (1 in 5 chance of occurring in any year), These are at various locations within this reach. Typical flooding is less than one metre and slow beyond which the river enters floodplain. moving. Under the ‘Do nothing’ scenario, the same There are about 34 residential properties at risk of numbers of properties have an increased risk of flooding during the one percent annual probability flooding.

10 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 4.0

For each of the reaches, a number of appropriate flood risk and river control structure options were short-listed, for further analysis and refinement. Options considered and their effects

Local and strategic affects were computer modelled • effect on surface water drainage. to test flood risk and identify any significant impacts. The impacts of these options are discussed overleaf. The analysis considered: Options we are already doing are shaded in grey, • flood risk to people, property and infrastructure those which are proposed are shaded in blue and • climate change those currently rejected are in green. • cost of the option and value of protected assets • impact on the natural environment, water level management and navigation

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 11 Reach 1: Alton/Haslemere to Tilford The reach has several habitat sites that are protected and are close to the watercourses. These include: The North Wey flows through Alton, in rural land • Thursley, Hankley and Frensham Commons through Farnham before joining with the South Wey SSSI and SPA at Tilford. The South Wey flows through Haslemere, again through rural land before joining with the North • Wealden Heaths Phase Two SPA Wey at Tilford. A number of tributaries join the North • East Hampshire Hangers SAC and South Wey including the Middle Bourne and the • Shortheath Common SSSI and SAC Lower Bourne. • Thursley, Ash and Chobham SAC A two-stage channel in Farnham is the only formal • Broxhead and Kingsley Commons SSSI flood defence in this reach. The river is not navigable and Moor Park SSSI. and is a prime example of a natural river. Several privately owned weirs maintain and control flows Sections of the reach are located in the East through mills. Hampshire and the Surrey Hills Areas of Outstanding

Map 2 Reach 1: Alton/Haslemere to Tilford

Farnham Park

Moor Park SSSI

Waverley Abbey

Frensham Common SPA Bentley Station SSSI

Alice Holt Romano – Thursley SAC British Kiln Sites Wealdon Heath Phase 2 SPA

Broxhead Common SSSI Hankley Common Chawton House SSSI and SPA

Kinesley Common SSSI Binswood SSSI Wealdon Heath Phase 2 SPA Broxhead House

East Hampshire Shortheath Common SSSI and SAC Hangers SSSI

Wealdon Heath Phase 2 SPA

Legend Main River International Nature Conservation sites, SPAs, RAMSAR, SACs Flood Zone 2 and 3 Existing BAP Habitats English Heritage Sites and Scheduled Monuments

National Environmental Sites, SSSI

12 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 Table 2 Strategic Options and Actions – Reach 1

Do nothing ✕ No further maintenance or repair work to the existing river or assets. Do minimum ✕ Similar to ‘Do nothing’, with reactive works to river and assets undertaken when required. Maintain ✓ Maintaining the existing river and assets in their current form. The channel is maintained where necessary, including debris and sand removal, tree works and general clearance works. Channel maintenance will be targeted according to flood risk. Existing floodplain storage is protected. Reduce ✓ In addition to ‘Maintain’ activities consequences • Raise the awareness of river and surface water flooding. Improve flood warning and improve the responses to flood warnings. (through Surface Water Management Plans, Local Resilience Forums) • In the long-term, promoting improved flood resilience/resistance (flood proofing or protection) to properties through the opportunities of redevelopment and self help by property owners.

Natural Beauty and are in the green belt. In addition, Large flood storage areas, with banks up to nine the southern sections are located on the boundary of metres high, upstream of Farnham and Tilford were the South Downs National Park. modelled to see if they reduced flood risks lower in the catchment. We will continue to maintain the flood channel at Farnham to relieve flooding. Elsewhere, the These storage areas were rejected, as they do not rural nature of the floodplains has a more local significantly reduce flood risk. They would also have level of flood risk. Here we will implement a very significant and unacceptable impact on the targeted maintenance and promote flood landscape, river ecology and protected areas within awareness and resilience/resistance measures the reach. to individual properties.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 13 Reach 2: Tilford to Shalford Urban developments, located in the outer reaches of floodplain, are at risk from river flooding. In This reach comprises of developed and undeveloped addition, these properties could be at risk of surface floodplain areas extending from Tilford to Shalford. water flooding during heavy downpours. The reach This reach includes the Cranleigh Waters and the contains several important environmental protected Tillingbourne, rivers that join the Wey upstream of sites close to the watercourses including: Guildford. The river flows through Elstead, Eashing and Godalming. • Thursley, Hankley and Frensham Commons SSSI and SPA The reach contains several privately owned weirs • Thames Basin Heaths SPA, Thursley, Ash Pirbrite that control water levels on the way to Godalming. and Chobham SAC From Godalming, the river is navigable on the Godalming and Wey Navigations. • Charleshill SSSI, Charterhouse to Eashing SSSI • Wey Valley Meadows SSSI and Colyers Hanger There are no significant flood defences in this reach. SSSI. During high flow events the river enters floodplain.

Map 3 Reach 2: Tilford to Shalford

Combe Bottom SSSI Hackhurst and White Downs SSSI

Colyers Hanger SSSI Puttenham and Crooksbury Common SSSI Wey Valleys Meadow SSSI Charterhouse SSSI Chilworth Albury Park Hillbury Hillfort Westbrook Blackheath SSSI Eashing SSSI Charleshill SSSI Anglo-Saxon Fortified Centre

Thursley and Ockham Bogs SAC

Thursley, Ash, Pirbright Bramley and Chobham SAC Smokejack Claypit SSSI Thursley SPA

Medieval Moated Site

Godalming

Legend Main River International Nature Conservation sites, SPAs, RAMSAR, SACs Flood Zone 2 and 3 Existing BAP Habitats English Heritage Sites and Scheduled Monuments

National Environmental Sites, SSSI

14 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 Table 3 Strategic Options and Actions – Reach 2

Maintain ✓ • Channel maintenance is targeted according to flood risk. Conveyance through towns and villages is maintained by regular sand removal, debris removal, tree works and general clearance works. • River control structures on the RWIS navigation are repaired and replaced at the end of their life (in partnership with owners if they are not our responsibility). Opportunities to improve fish and otter passage when control structures replaced. • Existing floodplain storage is protected. Reduce ✓ In addition to ‘Maintain’ activities, consequences • Raise the awareness of river and surface water flooding, improve flood warning and improve the responses to flood warnings. • In the long-term, promoting improved flood resilience to properties through the opportunities of redevelopment and self help by property owners.

Structural ✕ Construction of large (banks up to nine metres high) flood storage areas upstream of improvement Godalming at Farnham and Tilford. To reduce flood flows at Godalming and areas lower in the catchment. flood storage area Structural ✕ Construction of 1.5 metre high flood walls and embankments along property improvement boundaries in the floodplain in Godalming to protect against river flooding up to flood walls a two percent annual probability event (1 in 50 chance of occurring in any year). and embankments Compensatory flood storage excavation in the Lammas Lands.

The majority of the reach is located in the Surrey The preferred option is to reduce the consequence Hills Area of Outstanding Natural Beauty in the of flooding by: raising awareness, improving our green belt. flood warning and forecasting service, influencing spatial planning and promoting flood resilience and New flood walls and embankments are not resistance measures to individual properties. economically viable, even with a lower standard of protection. Storage areas were rejected, as they We can reduce the consequences of flooding, and do not significantly reduce flood risk. They would therefore the risk, through our ongoing partnerships also have an unacceptable visual impact on the with Local Authorities and our advice to public and landscape, river ecology and protected areas. developers. The continued availability of floodplain is critical in reducing the flood risk in this catchment.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 15 Reach 3: Shalford to Send (around a 20 percent probability in any one year). This reach comprises developed and undeveloped Due to a relatively flat floodplain, flooding can floodplain areas extending from Shalford to Send. be extensive even for low level events. Much of Within this reach the river flows through Guildford. Guildford is heavily developed with both commercial and residential development built up to the The river is navigable throughout this reach, with river banks. So a significant reduction in future water depths maintained by weirs and locks. development in the floodplain is unlikely. The River Wey is split into the natural river and Floodplain management is the most sustainable way the Wey Navigation Channel. The channel has of managing flood risk in Guildford. man-made sections of river constructed to ease navigation, typically taking a shorter route than the The reach contains two environmental designations natural river. which are situated in close to the rivers: • Sutton Place Registered Park and Garden There are no significant flood defences within this reach. Guildford is a historic county riverside town, • Riverside Park Local Nature Reserve in Guilford. where flooding from the Wey happens frequently

Map 4 Reach 3: Shalford to Send

Woking Palace

Papercourt SSSI

Thames Basin Heaths SPA

Sutton Place Ash to Brookwood Heaths

Medieval Moated Site Hackhurst Whitedowns SSSI Jelicoe Roof Garden Combe Bottom SSSI Guildford Castle

Colyers Hanger Henley Fort

Wey Valley Meadows SSSI Chilworth Albury Park Gunpowder Works

Legend Main River International Nature Conservation sites, SPAs, RAMSAR, SACs Flood Zone 2 and 3 Existing BAP Habitats English Heritage Sites and Scheduled Monuments

National Environmental Sites, SSSI

16 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 Table 4 Strategic Options and Actions – Reach 3

Strategic Option Action Do nothing ✕ • No further work on the river system – flood risk increases. • River structures are not repaired or replaced, and in time collapse. • The channel becomes overgrown, silts up causing a reduction in capacity. Do minimum ✕ • Blockages removed when and if they occur, reactive maintenance only Maintain ✓ • Channel maintenance is targeted according to flood risk. Conveyance through towns and villages is maintained by regular sand removal, debris removal, tree works and general clearance works. • River control structures on the RWIS navigation are repaired and replaced at the end of their life (in partnership with owner if they are not our responsibility). Opportunities to improve fish and otter passage when control structures are replaced. • Existing floodplain storage is protected. Reduce ✓ In addition to ‘Maintain’ activities, consequence • Raise the awareness of river and surface water flooding, improve flood warning and improve the responses to flood warnings. • In the long-term, promoting improved flood resilience to properties through the opportunities of redevelopment and self help by property owners. Reduce consequences ✓ Flood risk management in the Guildford urban area by using spatial planning to make Guilford sure that risk is managed and reduced as redevelopment takes place.

Structural improvement Construction of a large bypass tunnel to divert flow away from Guildford by taking tunnel bypass ✕ flow upstream of Guildford and releasing it back into the river downstream. Structural improvement Two metre high flood walls through Guildford providing a standard of protection above flood defence walls ✕ the two percent annual probability event (1 in 50 chance of occurring in any year).

Structural improvement Construction of large (banks up to nine metre high) storage areas in the upper upstream storage ✕ catchment (upstream of Farnham, Tilford and Elstead) to reduce flood flows Upper Wey in the lower catchment.

Additionally southern sections of the reach are The preferred option is to: reduce the consequence located in the Surrey Hills Area of Outstanding of flooding by raising awareness, improving our Natural Beauty. flood warning and forecasting service, influencing spatial planning and promoting flood resilience and A bypass tunnel is a high-risk option that is not resistance measures to individual properties. economically viable and will become less effective with flow increases due to climate change. Large We are working with Guildford Borough Council to flood storage areas in reach one and two were maximise opportunities to reduce flood risk through tested to see if they reduce flood risks lower in the redevelopment in Guilford town centre. The advice catchment. These were rejected, as they do not we give developers, the public and Local Authorities significantly reduce flood risk. They would also have helps reduce the risk of flooding and reduces the an unacceptable visual impact on the landscape, impacts when flooding does occur. The continued river ecology and protected environmental areas. availability of floodplain in the catchment is critical to flood risk management in this reach.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 17 Reach 4: Send to Wisley This reach contains developed and undeveloped Urban developments in the outer floodplain are at floodplain areas extending from Send to Wisley. risk of flooding, which is typically shallow and slow This reach also includes the Hoe Stream, a major moving. tributary to the west of the River Wey that flows We are working in partnership with Woking Borough through Woking and Old Woking. Council, to deliver flood defences on the Hoe Stream The River Wey is separated between the natural river through Woking. Construction is due to start in 2010. and the man-made Wey Navigation Channel which The reach contains a number of protected typically shortens the river route. environmental sites close to rivers, including: There are flood defences that reduce the likelihood • Woking Palace and Moat, Newark Priory, Pyrford of flooding at Send Marsh on the East Clandon Court Scheduled Monuments Stream. In other locations the river flows to • Thames Basin Heaths SPA floodplain. • Papercourt SSSI

Map 5 Reach 4: Send to Wisley

Woburn Farm Oatlands Place

Brooklands Racing Circuit

Pyrford Court Hillfort St George’s Hill

Brookwood Cemetary Papercourt SSSI Wisley Common SSSI Smarts Heath SSSI Ockham Common SSSI Reach 4 Newark Priory

Woking Palace Prey Heath SSSI

Papercourt SSSI

Combe Bottom SSSI Whitmore Common SSSI Sutton Place Hackhurst Whitedowns SSSI Thames Basin Heaths SPA Thursley, Ash, Pirbright Colyers Hanger and Chobham SAC

Wey Valley Meadows SSSI Albury Park Chilworth Gunpowder Works

Legend Main River International Nature Conservation sites, SPAs, RAMSAR, SACs Flood Zone 2 and 3 Existing BAP Habitats English Heritage Sites and Scheduled Monuments

National Environmental Sites, SSSI

18 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 Table 5 Strategic Options and Actions – Reach 4

Structural improvement ✕ 1.5 metre high flood walls and embankments along property boundaries in Old Woking floodplain providing a standard of protection of two percent annual probability event (1 in 50 chance of occurring in any year).

Structural improvement ✕ Large flood storage areas (banks up to nine metres high) in the upper catchment upstream storage upstream at Farnham, Tilford and Elstead to reduce flood flows in the lower Upper Wey catchment.

• Ash to Brookwood Heath SSSI The preferred option is to reduce the consequence • Whitmoor Common, Smarts and Prey Heaths and of flooding. We will do this by: continuing our Ockham and Wisley Common SSSIs. partnership with Woking Borough Council, raising awareness, improving our flood warning and Southern sections of the reach are also located in forecasting service, influencing spatial planning the Surrey Hills Area of Outstanding Natural Beauty. and promoting flood resilience and resistance New walls and embankments along property measures to individual properties. boundaries in Old Woking are not economically The new flood model from Tilford through Godalming viable. Storage areas were rejected, as they do not to the Thames will improve flood warnings. We have significantly reduce flood risk. They would also have completed and will continue to maintain channel an unacceptable visual impact on the landscape, improvements and flood walls that reduce the river ecology and protected areas within reach one. likelihood of flooding to 140 properties at Send Marsh on the East Clandon Stream.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 19 Reach 5: Wisley to Weybridge Urban developments at Brooklands Museum and Brooklands Road Weybridge risk flooding, which This reach comprises developed floodplain areas would typically be below one metre and slow moving. of Byfleet and Weybridge, extending from Wisley to the River Thames, and including the M25 motorway. As well as river flooding, low-lying properties risk The river flows through Byfleet, Brooklands, and surface water flooding during intense rainfall. Similar Weybridge. to what happened in 2000 at Sanway Road and Viscount Gardens near Byfleet. The natural river forms the main navigation channel, with water depths maintained by sluices, weirs or There are two protected sites that are situated close locks. to watercourses: There are no significant flood defences in this reach. • Woburn Farm Registered Park and Garden Apart from a minor section of earth bank upstream of • Brooklands Motor Racing Circuit Scheduled the Brooklands Museum and flood storage for recent Monument. developments at Brooklands. In flood, the river overflows onto the floodplain, which provides storage.

Map 6 Reach 5: Wisley to Weybridge

Oatlands Place

Woburn Farm

Brooklands Racing Circuit

Hillfort St George’s Hill

Wisley Common SSSI Ockham Common SSSI

Royal Horticultural Society (RHS)

Legend Main River International Nature Conservation sites, SPAs, RAMSAR, SACs Flood Zone 2 and 3 Existing BAP Habitats English Heritage Sites and Scheduled Monuments

National Environmental Sites, SSSI

20 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 Table 6 Strategic Options and Actions

Strategic Option Action Do nothing ✕ • No further work on the river system – flood risk increases. • River structures are not repaired or replaced, and in time collapse. • The channel becomes overgrown, silts up causing a reduction in capacity. Do minimum ✕ • Blockages removed when and if they occur, reactive maintenance only Maintain ✓ • Channel maintenance is targeted according to flood risk. Conveyance through towns and villages is maintained by regular sand removal, debris removal, tree works and general clearance works. • River control structures on the RWIS navigation are repaired and replaced at the end of their life (in partnership with owner if they are not our responsibility). Opportunities to improve fish and otter passage when control structures are replaced. • Existing flood plain storage in protected. Reduce consequences ✓ In addition to ‘Maintain’ activities, • Raise the awareness of river and surface water flooding, improve flood warning and improve the responses to flood warnings. • In the long-term, promoting improved flood resilience to properties through the opportunities of redevelopment and self help by property owners. Structural improvement ✓ Up to 1.5 metre high Flood walls and embankments along property boundaries in flood walls and the floodplain at Brooklands Road and Museum to protect against flooding above embankments one percent annual probability event (1 in 100 chance of occurring in any year). Structural improvement ✕ Construction of large (banks up to nine metres high) flood alleviation storage upstream storage areas in the upper catchment (upstream of Farnham, Tilford and Elstead) to Upper Wey reduce flood flows in the lower catchment.

Storage areas were rejected, as they do not Schemes at Brooklands Road and Brooklands significantly reduce flood risk. They would also have Museum are viable to provide protection for 205 an unacceptable visual impact on the landscape, residential properties, and to protect the Brooklands river ecology and protected areas. Museum against the one percent annual probability event (1 in 100 chance of occurring in any year). The preferred option is to reduce the likelihood These schemes are economically viable, but have and consequences of flooding. We will do this by: low national priority. raising awareness, improving our flood warning and forecasting service, influencing spatial planning and The Brooklands Museum scheme will need to be promoting flood resilience and resistance measures carried out by the museum. The Brooklands Road to individual properties. scheme priority will be monitored, to see if funding is available in future programmes.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 21 5.0 The strategy plan

The following three tables outline our draft strategy for the River Wey in the short, medium and long-term.

Table 7 Short-term Measures (0-5 years)

Measure Details

Maintain existing • Targeted maintenance and dredging to maintain the existing level of river standard capacity. Keeping the existing channels clear and free from obstruction to reduce the impacts from low order events (up to approximately five percent annual event probability a 1 in 20 chance of occurring in any year).

• Continue to develop System Asset Management Plans, in line with the strategy

and implement the Third Party Asset Policy. Ensuring systems and structures affecting flood risk perform to standards and third party structures are maintained. Heading • Continue to maintain, refurbish and replace river control structures, that we own, to maintain minimum depth for navigation and flow control in the main river. Carry out health and safety and motorisation improvements on structures to improve operation. Opportunities taken to improve habitat and fish passage when control structures are replaced.

• Develop further partnerships with the National Trust to best manage the operation and ownership of river control structures.

• As part of our Fisheries Action Plan, Biodiversity Action Plans (to maintain and improve SACs and SSSIs) and Water Level Management Plans, investigate and manage river flow control with partners to improve and create environmental habitat, improve and promote flood risk management. Identify degraded sections of river for enhancement and seek to control pollution and invasive species.

Reduce/improve Flood warning, flooding task group for Surrey and flood awareness consequences and emergency planning • Participation in Local Resilience Forums and the development of Multi-Agency Flood Plans with our partners that also identify critical infrastructure at risk of flooding and encourage appropriate action. • Work with partners, including the media, to make sure effective communication plans are in place before, during and in the recovery phase of a flooding incident. • Increase public awareness including encouraging people to sign-up for the free Floodline Warnings Direct service. We have revised flood warning areas so they are targeted to include communities and we carried out ‘door knocking’ to over 2,500 properties to increase sign up in late 2008. • Identify communities where an adequate flood warning service is not currently provided and investigate whether this situation can be improved. • Improve extreme rainfall event forecasting/warning and defining areas at risk of surface water flooding. Working with community partners to develop Surface Water Management Plans (produced by Local Authorities). • Encourage communities to work together with parish councils to produce Community Flood Plans.

22 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 Table 7 (continued) Short-term Measures (0-5 years)

Measure Details

Land use planning • Seek commitments from planning authorities to retain the remaining floodplain for flood risk management uses. • Encourage partners to develop methods, policies, strategies and initiatives that seek to increase the resistance and resilience of existing development at risk of flooding. • Agree the scale at which we are aiming for flood risk reduction through planning in the Guildford urban area. • Influence local authorities to adopt and apply local development framework policies, that make sure all new development in the floodplain is resistant and

resilient to flooding.

• Develop an enhanced flood risk hydraulic model from Tilford, through Guildford to the Thames, to improve flood warning and the advice we give Local Authorities, developers and the public.

Flood proofing and flood resilience to existing properties • Encourage property owners to take up resistance and/or resilience grants to protect existing properties at risk from flooding. Individual flood protection and

flood resilience measures are recommended where structurally sound. Possible measures include: raised finished floor levels, raised cupboards and electrical circuits, water resistant door frames, non-return valves on drainage pipes, water resistant plaster, air brick covers and tanking (waterproofing internal walls).

Structural Hoe Stream Flood Risk Scheme measures • Progress the Hoe Stream Flood Risk Management Scheme with Woking Borough Council. This is due to begin construction in 2010.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 23 Table 8 Medium-term Measures (6-25 years)

Measure Details

Local flood protection The Wey strategy identified locations at Brooklands Road and Brooklands Museum in Byfleet and Weybridge where it may be possible to reduce the probability of flooding. Actions include: • Progress those defence schemes that become more viable and are in areas where little redevelopment is expected. Advise Brooklands Museum of the flood risk

scheme details and encourage self protection.

• Safeguard land where appropriate.

Improve/reduce Land use planning, long-term adaptation of the urban environment to be more consequences flood resilient/resistant

• Progress Regional Biodiversity Action Plans for the River Wey, to enhance the environment.

• Establish and agree a long-term vision for the adaptation of urban floodplain and

river corridors, linked to redevelopment. For example:

– Encourage refurbishment of existing buildings that increases resilience and

resistance to flooding.

– Identify opportunities to recreate river corridors and wetland habitats in urban areas. Encourage new development and any redevelopment of these areas to

acknowledge these opportunities in their site layouts and set development back,

allowing space for water, habitat, wildlife and recreation.

– Encourage partners to assess the viability of future land swapping opportunities

in those areas where there is a risk of flooding.

Flood proofing and flood resilience to existing properties • Individual flood protection and flood resilience measures are recommended where structurally sound. Possible measures include: raised finished floor levels, raised cupboards and electrical circuits, water resistant door frames, non-return valves on drainage pipes, water resistant plaster, air brick covers, and tanking (waterproofing internal walls).

Table 9 Long-term Measures (25-100 years)

Measure Details

Maintain existing standard • Targeted maintenance to the existing level of river capacity. Keeping existing of protection (Do minimum) channels clear and free from obstruction to reduce the impacts from low order up to approximately five percent annual probability event (1 in 20 chance of occurring in any year). • Continue to maintain, refurbish and replace river control structures to maintain minimum depth required for navigation and flow control in main river. Opportunities taken to improve fish and otter passage when control structures replaced. • With partners investigate and manage river flow control through Water Level Management Plans to improve the environment, and promote flood risk management. Identify degraded sections of river for enhancement.

Improve/reduce • Review research on land use management to identify if this is effective in consequences reducing flood risk. • Continue to influence local, regional and national planning policy to achieve reductions in flood risk from development and redevelopment. • Promote Environmental Stewardship Schemes which have the potential to reduce flood risk by decreasing the volume of soil and water entering rivers from surrounding rural land.

24 Environment Agency River Wey Flood Risk Management Strategy Summary 2010 Have your say

This document has been designed for public consultation to inform people of the key issues and explain the recommendations set out in the draft strategy. If you know of someone who you think should see this document, please refer them to our website for an electronic copy: www.environment-agency.gov.uk/consultations If you do not have access to a computer, additional hard copies are available at the following libraries: Farnham, Godalming, Guilford, Byfleet, West Byfleet, Bramley, Cranleigh and Woking. Or you can call us on 08708 506 506 or write to us at the address below. We have completed a Strategic Environmental Assessment of our draft strategy. You can review copies of this report on our website and at the libraries listed above. This is a draft strategy and no final decisions have been made. We want to hear from you to help us to identify anything we may have missed in the preparation of this draft strategy. Please share with us your views of our recommended management options and any concerns you may have regarding strategy funding and implementation by Friday 14 May 2010. Your opinions on the recommended options are important: • What are your views on the preferred options? • What are your views on our partnership with the National Trust? • Do you have ideas for improvements? • Is there anything we’ve missed? • Do you have any other comments? By email: [email protected] Or by writing to: River Wey Draft Strategy Consultation 2009 Environment Agency Swift House Frimley Business Park Camberley Surrey GU16 7SQ What happens next?

Please let us have your comments by Friday 14 May 2010. We will consider all of the responses before making our final strategy recommendations later in the year. Your comments will help define the improvement and maintenance works that are required on the River Wey within the next five years, and inform the overall 100 year flood risk management strategy. We will keep you informed of our progress and share the outcomes of this consultation with you.

Environment Agency River Wey Flood Risk Management Strategy Summary 2010 25 Would you like to find out more about us, or about your environment? Then call us on 08708 506 506* (Mon-Fri 8-6) email [email protected] or visit our website www.environment-agency.gov.uk

Environment first: This publication is printed on a recycled paper using 100 per cent previously used waste. By-products from making the pulp and paper are used for composting and fertiliser, for making cement and for generating energy.

* Approximate call cost : 8p plus 6p per minute (standard landline). Please note, charges will vary across telephone providers.

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