(Including Thaw and Cadoxton) Catchment Flood Management Plan Summary Report January 2010 Managing Flood Risk We Are Environment Agency Wales

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Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Summary Report January 2010 managing flood risk We are Environment Agency Wales. 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. Environment Agency Wales. Out there, making your environment a better place.

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Environment Agency Wales Cambria House 29 Newport Road Cardiff CF24 0TP Tel: 0870 8506506 Email: [email protected] www.environment-agency.gov.uk

Front cover image: Glyn-neath flood alleviation scheme Introduction

I am pleased to introduce our summary of the Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan (CFMP). This CFMP gives an overview of the flood risk in the Ogmore to Tawe (including Thaw and Cadoxton) catchments and sets out our preferred plan for sustainable flood risk management over the next 50 to 100 years.

The Ogmore to Tawe (including Thaw and Cadoxton) influenced flooding a significant threat in the lower CFMP is one of 77 CFMPs for England and Wales. reaches of some rivers, for example the rivers Neath Through the CFMPs, we have assessed inland flood risk and Tawe. Following flooding in 1960, 1979 and 1998 across all of England and Wales for the first time. The a number of engineering schemes were constructed to CFMP considers all types of inland flooding, from rivers, reduce flood risk, for example at Bridgend, Glyn-neath groundwater, surface water and tidal flooding, but not and Cowbridge. flooding directly from the sea (coastal flooding), which is covered by Shoreline Management Plans (SMPs). Our We have worked with others to produce this CFMP, coverage of surface and groundwater is however limited including: local authorities, water companies, due to a lack of available information. environmental groups, land owners and land managers. Whilst there is broad support for this plan, The role of CFMPs is to establish flood risk management local authorities have raised concerns about limited policies which will deliver sustainable flood risk resources, prioritisation and the potential impact on management for the long term. This is essential if we current development and regeneration proposals. Also, are to make the right investment decisions for the land managers have raised concerns about how flood future and to help prepare ourselves effectively for risk is managed in rural areas. We cannot reduce flood the impact of climate change. We will use CFMPs to risk on our own. We will therefore work closely with all help us target our limited resources where the risks our partners to improve the co-ordination of flood risk are greatest. activities and agree the most effective way to manage flood risk in the future. This CFMP identifies flood risk management policies to assist all key decision makers in the catchment. It was This is a summary of the main CFMP document. If you produced through a wide consultation and appraisal need to see the full document, an electronic version process. However it is only the first step towards an may be obtained by emailing enquiries@environment- integrated approach to Flood Risk Management. As we agency.gov.uk. all work together to achieve our objectives, we must monitor and listen to each others progress, discuss what has been achieved and consider where we may need to review parts of the CFMP.

This CFMP covers eight main river catchments. River flooding is the main problem, with surface Chris Mills water flooding an issue in many areas, and tidally Director Wales

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 1 Contents

The purpose of a CFMP in managing flood risk 3

Catchment overview 4

Current and future flood risk 6

Future direction for flood risk management 12

Sub-areas 1 Upland Rivers 14 2 Tawe Valley 15 3 Lower Tawe 16 4 Upper Neath 17 5 Lower Neath 18 6 Port Talbot 19 7 Maesteg and Upland Valleys 20 8 Coastal Lowland 21 9 Bridgend Urban 22 10 Upper Thaw 23 11 Central Vale 24 12 Urban Cadoxton 25

Map of CFMP policies 26

Image: River Tawe, Swansea

2 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan The purpose of a CFMP in managing flood risk

CFMPs help us to understand the • internal drainage boards, water CFMPs aim to promote more scale and extent of flooding now companies and other utility sustainable approaches to and in the future, and set policies companies to help plan their managing flood risk. for managing flood risk within the activities in the wider context catchments. CFMPs should be used of the catchment; The policies identified in the to inform planning and decision CFMP will be delivered through making by key partners such as: • transportation planners; who a combination of different can use the plan to inform approaches. • the Environment Agency, who will their activities; use the plan to guide decisions Together with our partners, we on investment in further plans, • land owners, farmers and land will implement these approaches projects and actions; managers who manage and operate through a range of delivery plans, land for agriculture, conservation projects and actions. • local authorities, who can use and amenity purposes; the plan to inform spatial The relationship between the CFMP, planning activities and • the public and businesses to delivery plans, strategies, projects emergency planning; enhance their understanding and actions is shown in Figure 1. of flood risk and how it will be managed.

Figure 1. The relationship between CFMPs, delivery plans, projects and actions

Policy planning • CFMPs and SMPs. • Action plans define requirement for delivery plans, projects and actions.

Policy delivery plans (see note) Projects and actions • Influence spatial planning to reduce risk • Make sure our spending delivers the best and restore floodplains. possible outcomes. • Prepare for and manage floods • Focus on risk based targets, for example (including local Flood Warning plans). numbers of households at risk. • Managing assets. • Water level management plans.

• Land management and habitat creation. Note: Some plans may not be led by us – we may identify the need and encourage their development.

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 3 Catchment overview

The Ogmore to Tawe (including Approximately 70 per cent of the Tourism and recreation make Thaw and Cadoxton) CFMP is CFMP area is used for agriculture, a significant contribution to situated in South Wales. It covers whilst around 11 per cent is the local economy, due to the approximately 1,300 km2 and urban. The main towns include natural features of the area. around 196,000 properties, in an Swansea, Neath, Port Talbot, There are also a number of area extending from Swansea docks Bridgend, Llantwit Major, Dinas designated nature conservation, to Penarth point and the Brecon Powys, Cowbridge and Barry. landscape and heritage sites. Beacons to the north. Most are situated on river and Map 1 shows the location, tidal floodplains at the lower There are 429 kilometres of main extent and main features of reaches of the rivers. There are river including the rivers Tawe, the CFMP area. also a number of smaller towns Neath, Afan, Kenfig, Ogmore, established since the 18th and Ewenny, Col-huw, Thaw and 19th centuries around the historic Cadoxton. The catchments generally mining and metal working drain in a southerly direction, industries that developed in discharging into the Severn Estuary. South Wales.

“Primary trunk roads run up the valleys alongside many of the main rivers, providing key transport links between the rural communities and the large towns.”

Swansea Marina at the downstream extent of the River Tawe

4 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Map 1. Location and extent of the Ogmore to Tawe (including Thaw and Cadoxton) CFMP area

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 5 Current and future flood risk

Overview of the current flood risk What is at risk?

Flood risk is the combination of The sources of flood risk are: CFMPs assess how flood risk is likely two components; the likelihood to change in the next 100 years. They • river flooding accounts for the (or probability) of a particular do this at a strategic level and not at majority of all recorded flood flood event occurring and the a detailed, local level. events, with all of the CFMP consequence (or impact) that the catchments affected to a greater We used computer models to flood event would have if it occurred. or lesser degree; simulate river flows and produce The probability of a flood event indicative numbers of properties, • tidally influenced river flooding is the likelihood of a flood of that infrastructure and environmental can significantly increase flood size occurring within a one year features at risk. These models take risk on a number of rivers in period. It is described as an annual in to account the benefit of current their lower reaches affecting, exceedance probability (AEP) and flood defences. Where applicable, for example, Neath, parts of is expressed as a percentage. tidal influences on river flows have Swansea and also some For example, a 1% AEP flood event also been modelled. Where models sensitive environmentally has a one per cent chance or are not available we have based our designated sites; 0.01 probability of occurring in flood risk estimates on our Flood any one year. • surface water flooding is difficult Maps, which do not include flood to quantify as many incidents defences. Numbers produced are Unless otherwise stated, numbers are masked by the impact of sufficient for the purposes of the in this report are based on the 1% river flooding. However, it is CFMP only. AEP river flood event. More extreme believed to occur fairly frequently events can occur at any time. The There are currently approximately in many of the Ogmore to Tawe likelihood of an extreme event 9,900 properties across the CFMP catchments, particularly within occurring is small, although the area at risk from flooding during the Vale of Glamorgan. Surface consequences are potentially very a 1% AEP flood event. water flooding poses a low serious, particularly where defences risk of loss to life but can be a Flooding has an impact on could be overtopped. significant contributory factor infrastructure, including several In the past, many catchments to flooding; major transport routes and experienced flooding. Notable flood emergency service centres as well as • sewer flooding is caused by events occurred in December 1960 many local services such as schools overloading of sewerage systems and 1979 and October 1998 and and health centres. Agricultural land and is particularly a risk in Barry 2000. Bridgend was particularly is also affected by flooding. and Briton Ferry; affected in 1960, following which There are six special areas for flood defences were constructed. • groundwater flooding is not well conservation, three national The Vale of Glamorgan was widely documented in the CFMP area, nature reserves, 37 sites of special affected in October 2000 when except in the Vale of Glamorgan scientific interest and 19 scheduled heavy rain fell on already saturated where localised flooding has monuments located within the ground. The unprecedented rainfall occurred in Ewenny Village, 1% AEP floodplain. There are also in June and July 2007 also caused St Brides Major, Rhoose and around 100 hectares of high grade surface water flooding in parts of Barry in the past. agricultural land (Grade 2 or above) the Vale of Glamorgan. at risk from the 1% AEP flood event.

6 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Depending on the nature of Table 1. Key locations currently at risk in a 1% AEP flood event the environmental feature, flooding may have a negative Number of properties at risk Locations or positive impact. For example, > 1,000 Port Talbot, Swansea Central (tidal) flooding may create or enhance a habitat in some areas e.g. a new flood storage wetland, 500 to 1,000 Pencoed, Bridgend, or have the potential to cause Dinas Powys, Neath physical damage to the historic environment e.g. listed buildings 100 to 500 Swansea Vale, Ystalyfera/ and scheduled monuments. Ystradgynlais, Pontardawe

50 to 100 Ogmore Vale Where is the risk? 25 to 50 Maesteg, Glyn-neath To assess flood risk at a strategic level we have identified a number of key locations where we have carried out a more detailed analysis of flood risk. These are presented Table 2. Infrastructure currently at risk in a 1% AEP flood event in Table 1 and Map 2. This is not an exhaustive list of locations. Flood 51 electricity/gas sub-stations risk in all other areas has been considered in the development 4 emergency services of the CFMP. 1 sewage treatment works The largest flood risk is in Port Talbot in the Afan catchment, along 7 surgeries/health centres with Swansea Central in the Tawe catchment. There are also a number 10 schools/colleges of communities at risk in the Neath, Ogmore and Cadoxton catchments. main railway line and local rail services We recognise that there is potential at least 20 ‘A’ Roads risk from surface water and groundwater flooding in other areas 9 landfill sites of the CFMP, but there is limited information currently available. 17 historic landfill sites Table 2 lists some of the infrastructure currently at risk in the CFMP area.

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 7 Map 2. Number of properties currently at risk in a 1% AEP flood event

How we currently manage the risk in the catchment

We can split the work we do to management of the consequences • encouraging land use planning manage flood risk into two types: of flooding. This will include: to take account of flood risk in determining the location, layout • work which helps us to reduce • promoting awareness of and design of new development; the likelihood of a flood flooding so that organisations, occurring, and communities and individuals are • flood proofing properties and aware of the risk and are better infrastructure to improve the • work which helps us to deal with prepared to take action in time resilience (reducing the damage the consequences of flooding. of flood; from flood water) and the In the past we have focused on resistance (keeping water out) • providing flood warning services to avoid harm. reducing the likelihood of flooding to those at risk, to enable them by building flood defences. Other to take action; In this CFMP area, current flood risk measures have been used but not management is mainly reliant on as a primary response to flood • improved incident and flood warning, development control risk. It is now widely recognised emergency response by the and local defences at communities that managing flood risk to provide emergency services and by such as Bridgend. safe and sustainable communities those at risk from flooding; will require more emphasis on the

8 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Some of the ways in which we • asset management and flood forecasting model on the currently manage risk in the CFMP maintenance (managing River Afan and are in the process area include: current risk); of developing and testing models on the rivers Tawe, Ogmore and • flood risk mapping and data We build, operate and maintain flood defences, for example in Ewenny. We use this information management (understanding the to inform our flood warning risks now and in the future); Port Talbot, Bridgend, Cowbridge and Glyn-Neath. procedures. Flood risk mapping is Approximately 20,000 properties fundamental to understanding Maintenance differs from catchment to catchment. The across the CFMP area are covered flood risk and managing it by our flood warning service. We effectively. work we carry out includes removing blockages and debris aim to increase coverage (using We have recently carried out a from watercourses, inspecting our Floodline Warnings Direct) number of flood risk mapping assets, managing flood storage to over 75 per cent of the at risk studies in key risk areas, for areas and inspecting and population by 2010. example, Ystradgynlais. This is cleaning grids and trash screens. part of our work to continually • flood incident management update our hydraulic models • flood forecasting and warning (responding to flooding events); with the latest data so we can (flood event management); Emergency response to flood understand flood risk better We have set up a Flood events is mainly co-ordinated and improve the quality of Forecasting Centre with the through Civil Contingency our flood maps. Met Office. This allows us to arrangements and Local Resilience Forums. • strategic planning and continually improve our flood development control (managing forecasting capability. Our role is to advise our partners future risk and adapting to We produce flood forecasting through these arrangements. climate change); models to forecast river levels We support and participate in emergency response exercises. CFMPs and SMPs are an and flows. We currently have a important part of strategic planning, allowing us to look at a range of strategic measures. These include looking for opportunities to reduce run-off through managing rural land better and restoring floodplains through redevelopment of properties and infrastructure. We work with local authorities to make sure their local development plans address flood risk. We are currently working with City and County of Swansea on measures to reduce flood risk in the Swansea Vale Development site. This may include raising flood defence bunds (walls) and introducing new flood warning and flood management procedures.

Upstream view of the River Tawe, Swansea

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 9 The impact of climate change and future flood risk

Climate change, changes in the way • 20 per cent increase in peak AEP flood event will increase from land is used (for example, urban river flows; approximately 9,900 to around development) and the way rural 16,300, unless actions are taken • a total sea level rise of one land is managed will all influence to manage the increasing risks. metre by the year 2100; flood risk in the future. Sensitivity Figure 2 shows the difference testing identified that the main • 10 per cent decrease in forestry between current and future flood driver of change to future flood coverage which will increase risks from a 1% AEP flood event, risk is climate change, but changes flows in the upper reaches of assuming current management in the way rural land is used, affected catchments. activities. The most significant particularly a decrease in forestry increases in future risk occur in cover, may have some effect. Assuming the current level of flood risk management continues, we Swansea, Resolven and Glyn-neath. The following scenario was used estimate that by 2100 the number to analyse future flood risk: of properties at risk from the 1%

Figure 2. Current and future (2100) numbers of properties at risk from a 1% AEP flood event

4500

4000

3500

3000

2500

2000

1500

1000

500

0 Bridgend Dinas Powys Glyn-neath Maesteg Neath Ogmore Vale Pencoed Pontardawe Port Talbot Resolven Swansea Swansea Ystalyfera/ Central Vale Ystradgynlais

Current Future

10 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Table 3 provides a summary of Table 3. Key locations at risk in a future (2100) 1% AEP flood event key locations at risk in the future. Although river flooding remains Number of properties at risk Locations the main source of flooding in > 1,000 Port Talbot, Swansea Central (tidal), the future, the rise in sea level Pencoed will have a major effect on tidal flooding, especially around Swansea, the Aberafan area of 500 to 1,000 Bridgend, Neath, Dinas Powys, Port Talbot and Neath. Resolven, Swansea Vale, Ystalyfera/Ystradgynlais Table 4 shows the infrastructure at risk in the future. The most 100 to 500 Glyn-neath, Pontardawe notable increase is in the number of surgeries/health centres at 50 to 100 Ogmore Vale risk (increased from 7 to 23), and there are more schools/colleges 25 to 50 Maesteg and electricity/gas sub-stations affected. Sewage treatment works and landfill sites will also be increasingly affected. Table 4. Infrastructure at risk in a future (2100) 1% AEP flood event No significant increase in flood risk to environmental sites has 62 electricity/gas sub-stations been identified. 8 emergency services including police and fire station in Neath and Across the CFMP area there is Central Swansea fire station up to 320 hectares of high grade agricultural land (Grade 2 or 9 sewage treatment works above) at risk from a future 1% AEP flood event. 23 surgeries/health centres and Neath Port Talbot Hospital We expect surface water and groundwater flooding will 19 schools/colleges increase. Organisations will need to work together to investigate main railway line and local rail services and manage this flood risk in the future. at least 20 ‘A’ Roads

19 landfill sites

21 historic landfill sites

Glyn-neath Flood Alleviation Scheme

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 11 Future direction for flood risk management

Approaches in each sub-area

We have divided the Ogmore to Tawe (including Thaw and Cadoxton) CFMP into 12 distinct sub-areas which have similar physical characteristics, sources of flooding and level of risk. We have identified the most appropriate approach to managing flood risk for each of the sub-areas and allocated one of six generic flood risk management policies. These are shown in Map 3 and Table 5.

To select the most appropriate policy, the plan has considered how social, economic and environmental objectives are affected by flood risk management activities under each policy option. Policy analysis and selection is based on flood risk across the entire CFMP area and not just the key locations referred to earlier.

Map 3. Sub-areas in the Ogmore to Tawe (including Thaw and Cadoxton) CFMP

12 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Table 5. Policy options ➜ Policy 1 Areas of little or no flood risk where we will continue to monitor and advise This policy will tend to be applied in those areas where there are very few properties at risk of flooding. It reflects a commitment to work with the natural flood processes as far as possible.

➜ Policy 2 Areas of low to moderate flood risk where we can generally reduce existing flood risk management actions This policy will tend to be applied where the overall level of risk to people and property is low to moderate. It may no longer be value for money to focus on continuing current levels of maintenance of existing defences if we can use resources to reduce risk where there are more people at higher risk. We would therefore review the flood risk management actions being taken so that they are proportionate to the level of risk.

➜ Policy 3 Areas of low to moderate flood risk where we are generally managing existing flood risk effectively This policy will tend to be applied where the risks are currently appropriately managed and where the risk of flooding is not expected to increase significantly in the future. However, we keep our approach under review, looking for improvements and responding to new challenges or information as they emerge. We may review our approach to managing flood defences and other flood risk management actions, to ensure that we are managing efficiently and taking the best approach to managing flood risk in the longer term.

➜ Policy 4 Areas of low, moderate or high flood risk where we are already managing the flood risk effectively but where we may need to take further actions to keep pace with climate change This policy will tend to be applied where the risks are currently deemed to be appropriately-managed, but where the risk of flooding is expected to significantly rise in the future. In this case we would need to do more in the future to contain what would otherwise be increasing risk. Taking further action to reduce risk will require further appraisal to assess whether there are socially and environmentally sustainable, technically viable and economically justified options.

➜ Policy 5 Areas of moderate to high flood risk where we can generally take further action to reduce flood risk This policy will tend to be applied to those areas where the case for further action to reduce flood risk is most compelling, for example where there are many people at high risk, or where changes in the environment have already increased risk. Taking further action to reduce risk will require additional appraisal to assess whether there are socially and environmentally sustainable, technically viable and economically justified options.

➜ Policy 6 Areas of low to moderate flood risk where we will take action with others to store water or manage run-off in locations that provide overall flood risk reduction or environmental benefits This policy will tend to be applied where there may be opportunities in some locations to reduce flood risk locally or more widely in a catchment by storing water or managing run-off. The policy has been applied to an area (where the potential to apply the policy exists), but would only be implemented in specific locations within the area, after more detailed appraisal and consultation.

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 13 Sub-area 1

Upland Rivers

Our key partners are: Flood risk is relatively low and • increasing community and is not expected to increase individual awareness of flood Local authorities and communities significantly in the future. The risk and the actions both can level of flood risk is considered take to help themselves. Landowners and managers to be appropriately managed. Emergency services Actions to implement The vision and the policy include: preferred policy The issues in this Review and rationalise our sub-area Policy Option 3 – areas of low to current actions to ensure they moderate flood risk where we are are appropriate and targeted to This area includes the upland generally managing existing flood locations of greatest risk. reaches of the Rivers Tawe, Neath risk effectively. and Afan in the western part of Encourage and support our the CFMP area. The rivers are Our vision is to ensure the range partners to produce local long fast responding due to the steep of our actions is appropriate and term plans to manage all sources topography. Overtopping of river proportionate to the risks, now and of flooding, particularly at defences or natural ground levels in the future. Glyncorrwg and Pontneddfechan. is the primary cause of flooding. These plans should include an It is unlikely that we will be able to assessment of the consequences Approximately 90 properties justify construction of significant of flooding and actions to manage are currently at risk from the 1% new defences. We will continue to these. They should consider future AEP flood event, rising to around maintain existing defences, but it options and investment needs for 120 properties in the future. may not be justifiable to increase defences, emergency planning Affected communities are mostly their height in the future. Our vision and response, and development small geographically dispersed also includes: control issues. hamlets, but include the villages of • increased emphasis on actions Glyncorrwg in the Afan Valley and Engage and advise the local to manage the consequences Pontneddfechan in the Neath Valley. communities to encourage people of flooding; at risk to take action to help themselves e.g. to sign up to and respond to flood warnings.

Encourage and support land use and management changes by others, where these deliver flood risk management and wider environmental benefits e.g. in the upland and forested areas.

Glyncorrwg in the Afan Valley

14 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Sub-area 2

Tawe Valley

Our key partners are: The vision and Actions to implement

Local authorities and communities preferred policy the policy include:

D∑r Cymru Welsh Water Policy Option 5 – areas of moderate Encourage and support our to high flood risk where we can partners to produce local long term Infrastructure owners/operators generally take further action to plans to manage all sources of reduce flood risk. flooding, particularly at Ystalyfera, Land owners and managers Ystradgynlais and Pontardawe. Defences will continue to have a Emergency services These plans should include an role in reducing the likelihood of assessment of the consequences flooding. Overtopping of defences, of flooding, including from now or in the future, by extreme overtopping of defences, and The issues in this flood events could have serious actions to manage these. They sub-area consequences. We will continue to should consider future options and maintain our defences, but it may investment needs for defences, Historic development of the not be justifiable or acceptable to emergency planning and response, Tawe Valley has resulted in dense increase their height in the future. and development control issues. urbanisation along the valley floor. The outcome we seek is a The main river channel is highly Encourage and support studies by complementary set of flood risk modified with poor connectivity partners to identify surface water management actions by all partners with its natural flood plain. The and sewer flooding issues and at a local community level. These main source of flooding is from management options, particularly will include: the River Tawe. at Ystradgynlais and Ystalyfera. • increased emphasis on actions Approximately 440 properties are Engage and advise the local to manage the consequences currently at risk from the 1% AEP communities to encourage people of flooding from all sources; flood event, rising to around 700 at risk to take action to help properties in the future. Flood risk • increased community and themselves. is considered to be high, with a individual awareness of their flood Encourage and support owners majority of properties in Ystalyfera risks and adoption of actions both and operators of important and Pontardawe affected by flood can take to help themselves. infrastructure, to plan for and depths of more than 0.5 metres. manage their current and future There are a number of community flood risks. assets at risk, several utility Encourage and support land services premises and a number use and management changes of main roads affected. by others, where these deliver flood risk management and wider environmental benefits e.g. in the upland and forested areas.

River Tawe, Pontardawe

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 15 Sub-area 3

Lower Tawe

Our key partners are: induced flooding is predicted to Actions to implement increase at the lower reach, with City and County of Swansea increasing sea levels. There are also the policy include: surface water flooding issues that Local communities Encourage and support our we do not yet fully understand. partners to produce local long term D∑r Cymru Welsh Water plans to manage all sources of Flood risk is considered to be flooding, particularly at Tawe Vale Infrastructure owners/operators high at present with people, and Swansea Central. These plans properties, community assets should include an assessment Emergency services and infrastructure at risk. of the consequences of flooding, Defences will continue to have a including from overtopping of role in reducing the likelihood of defences, and actions to manage The issues in this flooding. Overtopping of defences, these. They should consider sub-area now or in the future, by extreme future options and investment flood events could have very needs for defences, emergency This area covers the main urban, serious consequences. planning and response, and commercial and redevelopment development control issues to areas of Swansea. The Tawe River is avoid inappropriate development the dominant source of flooding to The vision and in high risk areas. the north of the area, whilst at the downstream end, tidal flood risk is preferred policy Encourage and support studies by partners to identify surface water more significant. Policy Option 5 – areas of moderate to high flood risk where we can and sewer flooding issues and Approximately 1,910 properties are generally take further action to management options. currently at risk from the 1% AEP reduce flood risk. flood event, rising to around 3,440 Engage and advise the local properties in the future. Tidally We will continue to maintain communities, to encourage people our defences, but it may not be at risk to take action to help justifiable or acceptable to increase themselves e.g. to sign up to their height in the future. and respond to flood warnings.

The outcome we seek is a Encourage and support owners complementary set of flood risk and operators of important management actions by all partners infrastructure to plan for, and at a local community level. These manage, their current and will include: future flood risks.

• increased emphasis on actions to manage the consequences of flooding from all sources;

• increased community and individual awareness of their flood risks and adoption of actions both can take to River Tawe, Swansea help themselves.

16 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Sub-area 4

Upper Neath

Our key partners are: Approximately 20 properties Actions to implement are currently at risk from the 1% Neath Port Talbot County AEP flood event, rising to over the policy include: Borough Council 650 properties in the future. Encourage and support our partners The increasing future flood risk Local communities to produce local long term plans comes primarily from overtopping to manage all sources of flooding, D∑r Cymru Welsh Water of existing defences in a future particularly at Glyn-neath and 1% AEP flood event as a result of Resolven. These plans should Infrastructure owners/operators climate change predictions. The include an assessment of the A465 (T) road is also currently at Land owners and managers consequences of flooding, including risk of flooding. from overtopping of defences, and Emergency services actions to manage these. They should consider future options and The vision and investment needs for defences, The issues in this preferred policy emergency planning and response, and development control issues. sub-area Policy Option 4 – areas of low, moderate or high flood risk where Encourage and support studies by There are over seven kilometres of we are already managing the flood partners to identify surface water raised defences providing varying risk effectively but where we may and sewer flooding issues and standards of protection. The main need to take further actions to keep management options. urban areas of Glyn-neath and pace with climate change. Resolven are protected to a 1% Engage and advise the local AEP flood event standard from Our vision includes improved communities to encourage people main river flooding by recent integration of actions by all parties at risk to take action to help defence schemes. to manage all sources of flood risk. themselves.

We will continue to maintain Encourage and support owners our defences, but it may not be and operators of important justifiable or acceptable to increase infrastructure to plan for, and their height in the future. Our vision manage, their current and future also includes: flood risks, e.g. the A465(T).

• increased emphasis on actions Encourage and support land to manage the consequences use and management changes of flooding; by others, where these deliver flood risk management and wider • increased community and environmental benefits e.g. in the individual awareness of their upland and forested areas. flood risks and adoption of actions both can take to help themselves.

River Neath at Pont Walby, Glyn-neath

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 17 Sub-area 5

Lower Neath

Our key partners are: The vision and Actions to implement

Neath Port Talbot County preferred policy the policy include: Borough Council Policy Option 4 – areas of low, Encourage and support our partners Local communities moderate or high flood risk where to produce local long term plans we are already managing the flood to manage all sources of flooding, D∑r Cymru Welsh Water risk effectively but where we may particularly at Neath Town Centre, need to take further actions to keep Briton Ferry, Fabian Way/Red Jacket Network Rail pace with climate change. Pill (including the flood risk via Emergency services the canal system to Neath and Our vision includes improved Fabian Way). These plans should integration of actions by all parties consider climate change impacts to manage all sources of flood risk. and include an assessment of the The issues in this It may not be justifiable construct consequences of flooding, including sub-area significant new defences in the from overtopping of defences, and future to manage the impact of actions to manage these. They Dense urban areas dominate sea level rise and increased tidal should consider future options and the lower reaches of the Neath flooding. Our vision also includes: investment needs for defences, catchment. Tidal influence and • increased emphasis on actions emergency planning and response, overtopping of Tenant canal are to manage the consequences and development control issues to the main sources of flood risk. of flooding; avoid inappropriate development in Future increase in tide levels will high risk areas. result in tidal flood risk extending • increased community and further upstream. individual awareness of their Encourage and support studies by flood risks and adoption of partners to identify surface water Approximately 280 properties are actions both can take to help and sewer flooding issues and currently at risk from the 1% AEP themselves. management options. flood event rising to around 1,570 properties in the future. The main Engage and advise the local urban settlements at risk are Neath, communities, to encourage people Briton Ferry and Jersey Marine. Parts at risk to take action to help of the SA1/Fabian Way development themselves e.g. to sign up to and corridor are also shown to be at respond to flood warnings. greater risk in the future. The main Flood risk management actions London to Swansea railway is will be informed by the Swansea predicted to be at risk during the and Carmarthen Bay SMP review, future 0.5% AEP tidal flood event. currently being undertaken. The impact of tidal flooding on the lower reaches of the River Neath is the main risk. The natural ground level currently provides a level of protection to the majority of the area against current flood risk, however this protection will reduce in the future. Lower Neath River

18 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Sub-area 6

Port Talbot

Our key partners are: The vision and Actions to implement

Neath Port Talbot County preferred policy the policy include: Borough Council Policy Option 5 – areas of moderate Encourage and support our partners Local communities to high flood risk where we can to produce local long term plans generally take further action to to manage all sources of flooding, D∑r Cymru Welsh Water reduce flood risk. particularly at Port Talbot centre and Aberavon. These plans should Infrastructure owners/operators This area is very dependent on flood include an assessment of the defences to reduce the likelihood of Emergency services consequences of flooding, including flooding. Overtopping of defences, from overtopping of defences, and now or in the future, by extreme actions to manage these. They flood events could have serious should consider future options and The issues in this consequences. We will continue to investment needs for defences, sub-area maintain our defences, but it may emergency planning and response, not be justifiable or acceptable to and development control issues to This is a high density urban area. increase their height in the future. avoid inappropriate development in Fast responding rivers with a risk of The outcome we seek is a high risk areas. overtopping of defences on the Afon complementary set of flood risk Afan and Ffrwd Wyllt. We will continue to maintain management actions by all partners our defences and provide flood Approximately 3,840 properties at a local community level. These warnings. are currently at risk from the 1% will include: AEP flood event, rising to around Encourage and support studies by • increased emphasis on actions 5,790 properties in the future. The partners to identify surface water to manage the consequences of predicted flood extents during and sewer flooding issues and flooding from all sources; the 1% AEP flood event cover a management options. significant part of Aberavon as well • increased community and Engage and advise the local as Port Talbot centre. There are also individual awareness of their communities to encourage people surface water flooding issues that flood risks and adoption of at risk to take action to help are not well understood. actions both can take to help themselves e.g. to sign up to and themselves. People, properties, community respond to flood warnings. assets and infrastructure in Port Encourage and support owners Talbot, Aberavon, Tai Bach and and operators of important parts of Cwmafan are at risk. There infrastructure to plan for, and is an increasing risk of overtopping manage, their current and future of current defences in the future flood risks, particularly, utility due to climate change. This will services, Network Rail and Neath substantially increase the number Port Talbot Hospital. of properties at risk.

Afon Afan at Port Talbot Town Centre

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 19 Sub-area 7

Maesteg and Upland Valleys

Our key partners are: The vision and Actions to implement

Bridgend County Borough Council preferred policy the policy include:

Local communities Policy Option 3 – areas of low to Review and rationalise our moderate flood risk where we are current actions to ensure they are D∑r Cymru Welsh Water generally managing existing flood appropriate and targeted to locations risk effectively. of greatest risk. Infrastructure owners/operators Our vision is to ensure the range Encourage and support studies by Land owners and managers of our actions is appropriate and partners to identify surface water Emergency services proportionate to the risks, now and sewer flooding issues and and in the future. management options, particularly at Maesteg and Ogmore Vale. It is unlikely that we will be able to The issues in this justify construction of significant Engage and advise the local sub-area new defences. Where defences communities to raise awareness and exist we will continue to maintain encourage people at risk to take action The area contains scattered them but it may not be justifiable to help themselves e.g. to sign up to urban areas in the upper reaches to increase their height in the and respond to flood warnings. (Maesteg, Pontycymer, Pontymoel) future. Our vision also includes: Encourage and support owners and and ribbon development towards • increased emphasis on actions operators of important infrastructure Bridgend. Generally low risk with to manage the consequences to plan for, and manage, their current the main source of flooding from of flooding; and future flood risks. fast responding rivers in steep topography, although there is • increased community and Encourage and support land some risk of surface water flooding individual awareness of their use and management changes in Maesteg and Ogmore Vale. flood risks and adoption of by others, where these deliver actions both can take to help flood risk management and wider Within the urban centre of Maesteg themselves. environmental benefits e.g. in the there is a flood risk due to culvert upland and forested areas. blockage, as the River Llynfi threads its way through the town.

Approximately 30 properties are currently at risk from the 1% AEP flood event, rising to around 50 properties in the future. The main flood risk areas are Maesteg and Ogmore Vale.

Flood risk is contained in localised areas and we consider it to be appropriately managed at present.

River Llynfi, Maesteg

20 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Sub-area 8

Coastal Lowland

Our key partners are: The vision and Actions to implement

Local authorities preferred policy the policy include:

Local communities Policy Option 2 – areas of low to Work with partners to determine moderate flood risk where we can how the policy of reducing actions is D∑r Cymru Welsh Water generally reduce existing flood risk most appropriately communicated management actions. and implemented. Land owners and managers Our vision is to reduce the overall Encourage and support our level of our flood risk management partners to produce local long term activity over time. We will follow a plans to manage all sources of The issues in this risk based approach to rationalise flooding, particularly at defended sub-area our current activities and target communities. These plans should our actions and limited resources include an assessment of the Predominantly rural with scattered to locations of greatest risk. consequences of flooding, including settlements located mainly at from overtopping of defences, and the lower end of the catchments. It may not be justifiable to actions to manage these. They Tidally influenced river flooding is continue to maintain our defences, should consider future options and the dominant source at low return to replace them or to increase their investment needs for defences. periods, with surface water flooding height in the future. Our vision an issue in some areas, particularly also includes: Engage and advise the local in the East Vale. Groundwater communities to encourage people flooding is also believed to be • increased emphasis on actions at risk to take action to help an issue in some areas. to manage the consequences themselves. of flooding; Approximately 130 properties Carry out a modelling study at are currently at risk from the 1% • increased community and Ham Manor Caravan Park, to better AEP flood event, with little or no individual awareness of their understand the flood risk and increase expected in the future. flood risks and adoption of encourage and support our partners Ham Manor Caravan Park is also actions both can take to help to produce a plan to manage the believed to be at risk. The balancing themselves. current and future risks. ponds above Porthcawl help manage flood risk within the town. Encourage and support studies by partners to identify surface water and sewer flooding issues and management options, particularly East Vale.

Flood risk management actions will be informed by the findings of the Swansea and Carmarthen Bay SMP.

Ogney Brook, Llantwit Major

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 21 Sub-area 9

Bridgend Urban

Our key partners are: The vision and Actions to implement

Local authorities preferred policy the policy include:

Local communities Policy Option 4 – areas of low, Encourage and support our moderate or high flood risk where partners to produce local long D∑r Cymru Welsh Water we are already managing the flood term plans to manage all sources risk effectively but where we may of flooding, particularly at Infrastructure owners/operators need to take further actions to keep Wildmill Estate, Bridgend town Emergency services pace with climate change. centre and Pencoed. These plans should include an assessment Defences will continue to have a of the consequences of flooding, role in reducing the likelihood of including from overtopping of The issues in this flooding. Overtopping of defences, defences, and actions to manage sub-area now or in the future, by extreme these. They should consider flood events could have very serious future options and investment This is a highly urbanised area and consequences. We will continue to needs for defences, emergency includes the towns of Aberkenfig, maintain our defences, but it may planning and response, and Bridgend and Pencoed. The main not be justifiable or acceptable to development control issues to source of flooding is the Ogmore increase their height in the future. avoid inappropriate development River and its tributaries. Surface The outcome we seek is a in high risk areas. water flooding is also a key issue. complementary set of flood risk The Ogmore River and its tributaries We will continue to maintain management actions by all partners respond quickly to rainfall events, our defences and provide flood at a local community level. These while saturated ground following warnings. will include: prolonged rainfall is more Encourage and support studies by significant to the response in • increased emphasis on actions partners to identify surface water the Ewenny catchment, especially to manage the consequences and sewer flooding issues and at Pencoed. of flooding from all sources; management options. Approximately 2,000 properties • increased community and Engage and advise the local are currently at risk from the 1% individual awareness of their communities to encourage AEP flood event. However, with the flood risks and adoption of people at risk to take action impacts of climate change, this could actions both can take to help to help themselves. rise to at least 2,500 properties themselves. in the future with major transport Encourage and support owners routes increasingly affected. and operators of important infrastructure to plan for, and Defences currently reduce the manage, their current and future likelihood of flooding to the centre flood risks. of Bridgend and the settlements of Pencoed and Aberkenfig.

Flooding in Pencoed, 1998

22 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Sub-area 10

Upper Thaw

Our key partners are: Flood risk is considered to be Actions to implement managed appropriately at Vale of Glamorgan Council present with the operation the policy include: of the Cowbridge FAS. Local communities Review and rationalise our current actions to ensure they D∑r Cymru Welsh Water are appropriate and targeted to The vision and locations of greatest risk. preferred policy Encourage and support our The issues in this Policy Option 3 – areas of low to partners to produce local long sub-area moderate flood risk where we are term plans to manage all generally managing existing flood sources of flooding, particularly A recently constructed Flood risk effectively. at defended communities. Alleviation Scheme (FAS) has These plans should include an reduced the level of flood risk Our vision is to ensure the range assessment of the consequences within the main urban settlements of our actions is appropriate and of flooding, including from of Cowbridge and Llanblethian. proportionate to the risks, now overtopping of defences, and Elsewhere, informal defences and in the future. actions to manage these. They provide protection where individual We will continue to maintain the should consider future options and properties are at risk. The main Cowbridge FAS but it is unlikely investment needs for defences. source of flood risk is failure or we will be able to justify overtopping of these defences. Encourage and support studies by construction of significant new partners to identify surface water Approximately 20 properties are defences. Our vision also includes: and sewer flooding issues and currently at risk from the 1% AEP • increased emphasis on actions management options. flood event, rising to around 30 to manage the consequences properties in the future, assuming Engage and advise the local of flooding; continued operation of the FAS. communities to encourage people The FAS provides protection to at • increased community and at risk to take action to help least 185 additional properties. individual awareness of their themselves. flood risks and adoption of Develop a Reservoir Flood Plan for actions both can take to help Cowbridge FAS. themselves. Investigate options to improve flood forecasting and warning.

Cowbridge storage reservoir

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 23 Sub-area 11

Central Vale

Our key partners are: The vision and Actions to implement

Vale of Glamorgan Council preferred policy the policy include:

Local communities Policy Option 2 – areas of low to Work with partners to determine moderate flood risk where we can how the policy of reducing actions is D∑r Cymru Welsh Water generally reduce existing flood risk most appropriately communicated management actions. and implemented. The impacts Land owners and managers of significant change must be Our vision is to reduce the overall understood before implementation level of our flood risk management of change. activity over time. Typically this will The issues in this be achieved through a reduction Engage and advise the local sub-area in our routine maintenance. We community to encourage people will follow a risk based approach at risk to take action to help Predominantly rural with the main to rationalise our current activities themselves, particularly at sources of flooding from lowland and target our actions and limited Llancarfan. rivers and moorland runoff. resources to locations of greatest Flood risk from the main river is risk. Our vision also includes: Encourage and support studies by considered to be low with the partners to identify surface water majority of flooding contained to • increased emphasis on actions and sewer flooding issues and grazing pasture. There is a faster to manage the consequences of management options. catchment response after prolonged flooding; rainfall due to saturated ground Support opportunities to store water conditions which may cause some • increased community and or manage run-off to provide flood localised issues. individual awareness of their risk and environmental benefits, flood risks and adoption of e.g. in the upper catchments. Approximately 15 properties actions both can take to help are currently at risk from the 1% themselves. AEP flood event with no increase expected in the number of properties affected in the future. This is generally a low risk area with only a few properties in the village of Llancarfan affected.

Thaw Valley in flood

24 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan Sub-area 12

Urban Cadoxton

Our key partners are: The vision and Actions to implement

Vale of Glamorgan Council preferred policy the policy include:

Local communities Policy Option 5 – areas of moderate Encourage and support our to high flood risk where we can partners to produce local long term D∑r Cymru Welsh Water generally take further action to plans to manage all sources of reduce flood risk. flooding, particularly at Barry and Infrastructure owners/operators Dinas Powys. These plans should Our vision includes improved Land owners and managers include an assessment of the integration of actions by all parties consequences of flooding, including Emergency services to manage all sources of flood risk, from overtopping of defences, and particularly local surface water actions to manage these. They and sewer flooding in Barry and should consider future options and Dinas Powys. The issues in this investment needs for defences, emergency planning and response, sub-area A reduction of constrictions to flow and culverts. Particularly in urban and development control issues to avoid inappropriate development in The Cadoxton is a small catchment areas, e.g. Barry and Dinas Powys. high risk areas. with a high proportion of We will continue to maintain urbanisation. Barry and Penarth our defences, but it may not be Encourage and support studies by are the main urban centres. justifiable to increase their height in partners to identify surface water Flooding from lowland rivers is the future. Our vision also includes: and sewer flooding issues and the main source of risk. This can management options. be combined with surface water, • increased emphasis on actions sewer flooding and culvert to manage the consequences of Engage and advise the local blockage. Flooding can be flooding from all sources; communities to encourage people locally deep. at risk to take action to help • increased community awareness themselves. Approximately 1,130 properties are of their flood risks and adoption currently at risk from the 1% AEP of actions they can take to help Encourage and support owners flood event, rising to around 1,350 themselves. and operators of important properties in the future. The main infrastructure to plan for, and areas of flood risk are located in manage their current and future Dinas Powys and Barry. In the future flood risks. Particularly the Dow there is a significant increase in Corning Complex. risk to the Dow Corning chemical Investigate the potential for utilising complex and around Barry Dock storage within Cog Moors and Sully commercial areas. Moors upstream of the Dow Corning Flood risk management actions will chemical complex to reduce future be informed by the findings of the flood risk. Swansea and Carmarthen Bay SMP review, currently being undertaken.

Sully Moors, July 2009

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 25 Map of CFMP policies

4 2

3 5

6 7

10 8

11 12

Legend

Preferred Policy

■■ Policy 2

■■ Policy 3

■■ Policy 4

■■ Policy 5

River Network

26 Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan ■■ Sub-area 1 – Upland Rivers ■■ Sub-area 7 – Maesteg and Upland Valleys Flood risk is relatively low and is not expected to Flood risk is relatively low and is not expected to increase significantly in the future. The current level of increase significantly in the future. The current level of flood risk management is considered to be appropriate flood risk management is considered to be appropriate but will be reviewed and reprioritised to ensure our but will be reviewed and reprioritised to ensure our activities remain appropriate to the risk. activities remain appropriate to the risk.

■■ Sub-area 2 – Tawe Valley ■■ Sub-area 8 – Coastal Lowland Flood risk is high and is expected to increase Flood risk is low and is not expected to increase significantly. There is a risk of harm to life, risk to significantly in the future. Flood risk management infrastructure and community disruption. Further will be reduced over time in a managed way but flood risk management action is required in order to flood warning and maintenance of existing defences reduce flood risk to an appropriately managed level. will continue.

■■ Sub-area 3 – Lower Tawe ■■ Sub-area 9 – Bridgend Urban Flood risk is high and is expected to increase Flood risk is considered to be managed appropriately significantly. There is a risk of harm to life, risk to at present. Further flood risk management actions infrastructure and community disruption. Further will be required to sustain the current level of risk flood risk management action is required in order to into the future. reduce flood risk to an appropriately managed level. ■■ Sub-area 10 – Upper Thaw ■■ Sub-area 4 – Upper Neath Flood risk is currently managed by a new Flood Flood risk is considered to be managed appropriately Alleviation Scheme. Future levels of risk will remain at present. Further flood risk management actions similar assuming that this stays operational. We will be required to sustain the current level of risk will continue with the current level of flood risk into the future. management activity to manage flood risk at the current level. ■■ Sub-area 5 – Lower Neath Flood risk is considered to be managed appropriately ■■ Sub-area 11 – Central Vale at present. Further flood risk management actions Flood risk is low and is not expected to increase will be required to sustain the current level of risk significantly in the future. Flood risk management into the future. will be reduced over time in a managed way.

■■ Sub-area 6 – Port Talbot ■■ Sub-area 12 – Urban Cadoxton Flood risk is high and is expected to increase Flood risk is high and is expected to increase significantly. There is a risk of harm to life, risk to significantly. There is a risk of harm to life, risk to infrastructure and community disruption. Further infrastructure and community disruption. Further flood risk management action is required in order to flood risk management action is required in order to reduce flood risk to an appropriately managed level. reduce flood risk to an appropriately managed level.

Environment Agency Wales Ogmore to Tawe (including Thaw and Cadoxton) Catchment Flood Management Plan 27 Would you like to find out more about us, or about your environment?

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