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. Published by: Environment Agency Wales Cambria House 29 Newport Road Cardiff CF24 0TP Tel: 0870 8506506 Email: [email protected] www.environment-agency.gov.uk © Environment Agency Wales All rights reserved. This document may be reproduced with prior permission of the Environment Agency. January 2010 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 © Crown copyright 2009. All rights reserved. km Licence number 100026380 0 1.25 2.5 5 7.5 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.