Draft River Hull Flood Risk Management Strategy. May River Hull Flood Risk Management Strategy Report

Transcription

1 Draft River Hull Flood Risk Management Strategy May 2010 River Hull Flood Risk Management Strategy Report

2 River Hull Flood Risk Management Strategy Report

3 Draft River Hull Flood Risk Management Strategy Strategy Report May 2010 Halcrow Group Limited has prepared this report in accordance with the instructions of their client, for their sole and specific use. Any other persons who use any information contained herein do so at their own risk. Halcrow Group Limited Document History JOB CODE: WBRHPS DOCUMENT REF: RHFRMS Strategy Report v6.doc Revision Purpose Description Originated Checked Reviewed Authorised Date 0 DRAFT JHG AJT TM MM 18/05/10 River Hull Flood Risk Management Strategy Report

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5 Contents Section Glossary of terms At a glance Page i vii 1. Introduction The Environment Agency vision Creating a better place priorities and targets Strategy policy links Strategy aims and objectives Benefits of a strategic approach Strategy development and review 5 2. Catchment overview The River Hull catchment and definition of the study area Environmental context Definition of catchment areas Links to other plans opportunities and constraints Flood risk Definitions Causes of flooding Flood history Flood management in the River Hull catchment Assessment of current flood risk Flood risk in the future Appraisal of options Appraisal criteria for River Hull Strategy options Options for consideration Options appraisal Strategy elements and final options Summary of economics Summary of Strategic Environmental Assessment Impact of climate change Our Plan Introduction Proposed flood risk management measures Strategy action plan Procurement Strategy Strategy risks Strategy review 72 River Hull Flood Risk Management Strategy Report

6 List of Tables Table 1.1 Our objectives for the River Hull Flood Risk Management Strategy 3 Table 1.2 Reasons for a strategic approach 4 Table 2.1 River Hull Strategy area overview 7 Table 2.2 Hull and Coastal Streams CFMP Policy units and preferred policies 18 Table 3.1 Recorded flood events in the River Hull catchment 29 Table 3.2 River Hull flood defence assets 31 Table 3.3 Onset of fluvial flooding for River Hull catchment (taking into account the effect of the defences) 38 Table 4.1 Summary of initial flood risk management options 49 Table 4.2 Benefit cost ratio for pumping station appraisal in the maintain option 53 Table 4.3 Benefit cost ratio for pumping station combinations appraisal in the maintain option 54 Table 4.4 Summary of Strategy options (combinations of Strategy elements) 56 Table 4.5 Summary of economic damages (Whole Catchment) 61 Table 4.6 Summary of economic damages (upper and middle catchment areas only) Table 4.7 Summary of economic damages (lower catchment area only) List of Figures Figure 1-1 Stages in the development of the River Hull Flood Risk Management Strategy 6 Figure 2-1 Strategy location and study area 8 Figure 2-2 Topography of the Strategy area 9 Figure 2-3 Upper River Hull from Wansford Bridge 10 Figure 2-4 Lower River Hull through Kingston-upon-Hull 11 Figure 2-5 Key features of the River Hull system 12 Figure 2-6 River Hull catchment areas 16 Figure 2-7 Local Authority boundaries in the River Hull Strategy study area 20 Figure 3-1 Overtopping of River Hull at Wilfholme 26 Figure 3-2 Flooding near Wilfholme caused by Beverley and Barmston Drain being unable to discharge 27 Figure 3-3 Location of natural springs 28 Figure 3-4 Surface water flooding in Hull 29 Figure 3-5 Flood defences in the study area 33 Figure 3-6 Predicted extent of flooding (present day) 37 Figure 4-1 Options appraisal process 46 Appendices Appendix A Options Appraisal Report Appendix B Environmental Report River Hull Flood Risk Management Strategy Report

7 Glossary of terms Term Appraisal Biodiversity Action Plan (BAP) Catchment Catchment Flood Management Plan (CFMP) Conservation Area (CA) County Structure Plan Critical Ordinary Watercourse (COW) Environment Agency Environmental Vision Environmental Impact Assessment (EIA) Flood Alleviation Scheme (FAS) Flood Defence Floodplain Meaning / Definition The process of defining objectives, examining options and evaluating costs, benefits, risks, opportunities and uncertainties before a decision is made. The 1992 Biodiversity Convention in Rio led to the formation of the UK Biodiversity Steering Group which created action plans to conserve 116 species and 14 habitats together with recommendations for future Biodiversity Action Plans (BAPs) as well as a number of Local Biodiversity Action Plans (LBAPs). The Environment Agency has an obligation to report to Government on all losses and gains of habitats and species protected by Biodiversity Action Plans that result from its flood and coastal defence work, and therefore any flood defence policies that are formulated for the catchment should seek to protect, or where possible, enhance sites which are important for BAP habitats and species. A surface water catchment is the total area that drains into a river. Catchment Flood Management Plans (CFMPs) are a large-scale strategic planning framework for the integrated management of flood risks to people and the developed and natural environment in a sustainable manner. The Aire CFMP will incorporate flood risk policy into strategic and local plans and ensure its local implementation through development control. This will prevent inappropriate development in the floodplain, thereby reducing the risk of flooding. A Conservation Area is an area of special architectural or historic interest, the character or appearance of which it is desirable to preserve or enhance. A County Structure Plan sets out policies and major proposals to guide new development, and conserve the natural and built environment. It must implement national and regional polices, in particular the Planning Policy Guidance (PPG) notes, and shapes planning and development. A watercourse which is non main river, but which the Environment Agency and operating authorities deem critical as they have the potential to put large numbers of people and property at risk from flooding. Our vision for the environment and a sustainable future is: A healthy, rich and diverse environment in England and Wales, for present and future generations To achieve the targets that will make the vision a reality the Agency has identified nine key themes or frameworks for change through which it will work for a more sustainable future. 1. A better quality of life: the Agency will work with all sectors to enhance the quality of the environment and the services it provides for business, anglers, the boating community and other users of the waterways, farmers, planners and all sections of the community. 2. An enhanced environment for wildlife: the Agency will ensure that its activities and those it authorises do not threaten key species and habitats; 3. Cleaner air for everyone 4. Improved and protected inland and coastal waters: the Agency will work to clean up polluted waters and to reduce the risk of further pollution; 5. Restored protected land with healthier soils. 6. A greener business world 7. Wiser sustainable use of natural resources 8. Limiting and adapting to climate change 9. Reducing flood risk: the Agency will improve flood defences and information on flood risks For further information refer to our website And Environmental Impact Assessment is a statutory process for a development which is likely to have an adverse environmental impact, with the impacts identified and assessed to determine their significance. A scheme designed to reduce the risk of flooding in a specific location. A structure (or system of structures) for the alleviation of flooding. Any area of land over which water flows or is stored during a flood event or would flow but for the presence of flood defences. River Hull Flood Risk Management Strategy Report i

8 Term Flood Risk Management Flood Map Flood Storage Area Flood Zones Geographical Information System (GIS) Land Use Local Biodiversity Action Plan (LBAP) Local Development Framework (LDF) LiDAR Listed Building National Nature Reserve (NNR) National Property Database Meaning / Definition The activity of modifying the frequency or consequences of flooding to an appropriate level (commensurate with land use), and monitoring to ensure that flood risks remain at the proposed level. This should take account of other water level management requirements, and opportunities and constraints. Maps showing the Agency s best estimate of the extent of the floodplain. These cover all Main Rivers and some ordinary watercourses. The floodplain is defined as the area having a 1% per annum risk of fluvial inundation, or a 0.5%p.a risk of tidal inundation. Defended areas are also shown. These maps are sometimes referred to as the Indicative Flood Map. An area of land which may be used to temporarily store an increased depth or extent of floodwater to reduce flood risk to communities downstream. This map shows natural floodplain 'zoned' into three areas based on risk for the purpose of PPG25. They show the flooding that would occur if there were no flood defences and have been created from a combination of detailed models where available, generalised models based on the national Digital Terrain Model and relevant historic flood data. Watercourses that have a catchment size of less than 2 square kilometres have not been included. A GIS is a computer-based system for capturing, storing, checking, integrating, manipulating, analysing and mapping spatially referenced data. Various types of activities, developments, cropping types, etc, for which land is used. A local agenda (produced by the local authority) with plans and targets to protect and enhance biodiversity and achieve sustainable development. The Agency is committed to Biodiversity Action Plans and works with central government (Rio Earth Summit, 1992) to realise LBAP objectives. Biodiversity Action Plans are split into those concerning habitats (Habitat Action Plans) and those concerning species (Species Action Plans). While LBAPs may have been developed for species or habitats of particular local interest, those species or habitats for which there is a BAP on a national level will also be conferred protection even where a LBAP may not exist. The Local Development Framework (LDF) is a non-statutory term to describe a folder of documents which includes the local planning authority s local development documents. LiDAR (Light Detection and Ranging) is an airborne mapping technique which uses radar to measure ground elevation, resulting in a terrain map used to assess flood risk. In England, Listed Buildings are designated by English Heritage. They are buildings or permanent structures with special architectural or historic interest (exterior or interior), and are graded I, II* and II. National Nature Reserves are designated under the National Parks and Access to the Countryside Act 1949 or the Wildlife and Countryside Act 1981 (as amended) primarily for nature conservation, but can also include sites with special geological of physiographic features. All NNRs are nationally important and are all among the best examples of a particular habitat, They are usually owned or leased by Natural England, or managed in accordance with a Nature Reserve Agreement with the landowner or occupier or an approved body such as a wildlife trust. Further information about NNRs can be found on Natural England s website site: The National Property Database (NPD) gives address-point (location) data of all types of properties, in order to calculate economic damages of flood events. River Hull Flood Risk Management Strategy Report ii

9 Term Planning Policy Guidance Note 25: Development and Flood Risk (PPG25) Planning Policy Statement 25: Development and Flood Risk (PPS25) Preliminary Strategic Review (PSR) Ramsar Site Regional Spatial Strategy Scheduled Monuments (SMs) Site of Special Scientific Interest (SSSI) Meaning / Definition One of a series of Planning Policy Guidance notes (PPGs) issued by DTLR to advise local planning authorities and developers. While PPGs are not statutory, planning authorities are obliged to consider them in preparing plans and determining planning applications. PPG25, issued in July 2001, raises the profile of flood risk, which should be considered at all stages of the planning and development process and on a catchmentwide basis. It emphasises the need to act on a precautionary basis and to take account of climate change. It provides advice on future urban development in areas subject to flood risk, subjecting proposals to a sequential response (dependent on the degree of risk) and promotes the concept of Sustainable Drainage Systems (SuDS) in new development or re-development. For further information please refer to the Office of the Deputy Prime Ministers planning website: This is a draft revision of PPG25, to clarify and strengthen the core policies, making it easier and clearer to understand. This will include the clarification of the sequential test. For further information please refer to the Department for Communities and Local Government website: A high level review of flood risk management issues in a catchment or part of a catchment, based on existing information. Used by North-East region of the Environment Agency to identify urgent flood defence works to be progressed in areas of very high risk, and as a first step in preparing Flood Risk Management Strategies. The PSRs for the Upper Aire and Lower Aire have also provided information for use within the Aire CFMP. Ramsar sites are wetlands of international importance designated under the Ramsar Convention (1971) and meeting those criteria for identifying wetlands of international importance. The Ramsar Convention is an intergovernmental treaty providing the framework for national action and international cooperation for the conservation and wise use of wetlands and their resources, especially as waterfowl habitat. Ramsar sites previously received SSSI designation status but the majority of these sites are also designated under the EU Birds Directive, and are currently managed as protected areas through the Habitat Regulations. Further information can be located on the Ramsar convention on wetlands website: Regional Spatial Strategies (RSS) provide a spatial framework to inform the preparation of local development documents, local transport plans and regional and sub-regional strategies and programmes that have a bearing on land use activities (Government Office for Yorkshire and the Humber, 2004). To protect archaeological sites for future generations, the most valuable of them may be scheduled. Scheduling is the process through which nationally important sites and monuments are given legal protection by being placed on a list, or schedule. English Heritage identifies sites in England, which should be placed on the schedule by the Secretary of State for Culture, Media and Sport. The current legislation, the Ancient Monuments and Archaeological Areas Act 1979, supports a formal system of Scheduled Monument Consent for any work affecting a designated monument. Further information can be found on English Heritage s website: Sites of Special Scientific Interest (SSSIs) are notified under the Wildlife and Countryside Act 1981 (as amended) and the Countryside and Rights of Way (CROW) Act 2000 for their flora, fauna, geological or physiographical features. Notification of a SSSI includes a list of operations that may be harmful to the special interest of the site. The Wildlife and Countryside Act 1981 (provisions relating to SSSIs) has been replaced by a new Section 28 in Schedule 9 of the CROW Act. The new Section 28 provides significantly enhanced protection for SSSIs. Government policy is to give land, notified as SSSI, protection through the statutory planning system. Planning Policy Guidance on Nature Conservation (DoE, PPG No. 9, 1994) makes it clear that nature conservation can be a significant material consideration in determining planning applications, especially in or near to SSSI. It goes on to state, the key importance of SSSI means that development proposals in or likely to affect them must be subject to special scrutiny. The Agency is notified of SSSIs by Natural England under Section 8 of the Environment Act (1995). For further information refer to Natural England s website: River Hull Flood Risk Management Strategy Report iii

10 Term Special Protection Area (SPA) Strategic Environmental Assessment (SEA) Strategic Flood Risk Assessment (SFRA) Sustainability Washlands The Wildlife and Countryside Act (WCA) 1981, and the Countryside and Rights of Way (CRoW) Act 2000 Meaning / Definition Special Protection Areas (SPAs) are strictly protected sites classified in accordance with Article 4 of the EC Directive on the conservation of wild birds (79/409/EEC), also known as the Birds Directive, which came into force in April They are classified for rare and vulnerable birds, listed in Annex I to the Birds Directive, and for regularly occurring migratory species. SPAs are designated for their international importance as breeding, feeding and roosting habitat for bird species. The Government is required to consider the conservation of SPAs in all planning decisions. SPAs receive SSSI designation under The Countryside and Rights of Way (CRoW) Act 2000 and The Wildlife and Countryside Act 1981 (as amended). For further details refer to the European Commission: website: environment/nature/spa/intro_en.pdf and The Joint Nature Conservation Committee website at A systematic appraisal of the potential environmental consequences of policy/ planning/ strategy decisions prior to approval. The SEA is, in effect, an environmental assessment of certain plans and programmes in compliance with the SEA Directive 2001/42/EC. The SEA directive is implemented through the Environmental Assessment of Plans and Programmes Regulations, making SEA mandatory for plans that are likely to have significant environmental effects. While it shares some similarity with Environmental Impact Assessment, the SEA goes further through considering wider impacts such as those on population, human health and cultural heritage. A Strategic Flood Risk Assessment (SFRA) is intended to provide an understanding of flood risk, outlining the extent and nature of flooding within the flood risk zones. Sustainable development is development which the meets the needs of the present without compromising the ability of future generations to meet their own needs (From Our Common Future (The Brundtland Report) Report of the 1987 World Commission on Environment and Development). The government s Securing the future: delivering UK sustainable development strategy report (March 2005) presents the set of shared UK principles that it will use to achieve the country s sustainable development purpose: - living within environmental limits, -ensuring a strong, healthy and just society, -achieving a sustainable economy, -promoting good governance, -using sound science responsibly. Washlands are the area of the floodplain where water is stored during flood events. Artificial structures can be added to control the amount of water stored and the timing of its release downstream. Under Section 28 of the Wildlife and Countryside Act 1981, areas of land considered to be of national importance for nature conservation, subject to a statement of their scientific value, are notified as Sites of Special Scientific Interest (SSSIs). Although SSSIs are notified by Natural England (EN), the Statutory conservation body, management of a SSSI is the responsibility of the landowner, who is provided with a list of Potentially Damaging Operations (PDOs), activities that may damage the scientific interest of the site. EN, as the regulatory body for SSSIs, must be given notice of any PDO which is proposed to take place on a SSSI. The CRoW Act 2000 increased the powers of statutory bodies to prevent damage to SSSIs, increased penalties for damage to sites and granted new powers to the courts to order the restoration of sites after they have been damaged. Statutory bodies have also been given new powers to refuse consent for PDOs without having to provide compensation payments to landowners. The Wildlife and Countryside Act is divided into four parts. Part I is concerned with the protection of wildlife, Part II relates to the countryside and national parks (and the designation of protected areas), Part III covers public rights of way, Part IV deals with miscellaneous provisions of the Act The designation of protected species is included in Schedules 1, 5 and 8 of the Act, which list protected birds, protected animals and protected plants, respectively. River Hull Flood Risk Management Strategy Report iv

11 Term World Heritage Sites Meaning / Definition World Heritage Sites receive designation from the United Nations Educational, Scientific and Cultural Organisation (UNESCO) which seeks to encourage identification, protection and preservation of cultural and natural heritage around the world considered to be of outstanding value to humanity. This is embodied in an international treaty called the Convention concerning the Protection of the World Cultural and Natural Heritage, adopted by UNESCO in They receive no additional statutory protection from such designation, although there is an assumption that they will already be of such importance to receive protection from their status alone, if not from existing Statutory arrangements and laws (such as Heritage, Conservation, Environmental, Planning etc. at national and local level). Planning authorities regard the status of World Heritage Sites as a material consideration in determining planning applications and applications for permission for development affecting listed buildings and their setting. For further details refer to the UNESCO website: River Hull Flood Risk Management Strategy Report v

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13 At a glance The River Hull forms part of a complex network of rivers, drains, pumping stations and flood defence banks and walls stretching from above Driffield in the north to the Humber estuary in the south. The network is managed to provide flood protection for around 100,000 properties and around 5,500 hectares of land. We have developed a draft strategy to identify the risk of flooding now and in the future, taking climate change predictions into account. We will use the findings to make the case for future investment in order to manage flood risk. In developing the draft Strategy we have carried out detailed technical and economic analysis. We have also met and talked with local people and partner organisations and have taken their views into account. Key characteristics and issues of the Hull catchment Much of the area is low lying and the relationship between the rivers and drains, the Humber Estuary, groundwater and surface water is very complex. Extensive flood defences along the River Hull and the Humber estuary frontage greatly reduce the risk of flooding to people, properties and land. Without these defences the area would be very vulnerable to flooding. The defences in the lower part of the catchment in Kingston upon Hull are largely privately owned and are in a variable state of repair. Some are in a very poor condition. The flood banks in the central part of the catchment are in reasonable condition. Some of the flood banks in the upper part of the catchment are in poor condition. The Environment Agency own and operate five pumping stations in the catchment. Some of these do not reduce the risk of flooding to property, although they do play an important land drainage role by reducing the frequency and duration of water logging of 1400 hectares of agricultural land in a typical winter. Much of this land is already prone to flooding. Challenges and opportunities Flood risk benefit to people and property in Kingston Upon Hull and surrounding area means flood protection schemes in this area are very likely to attract funding. Funding for flood risk management activities comes from tax payers and is given to us each year by government. We need to prioritise to make sure we get the best value for the money we have. The assessment process gives priority to work that protects people and property. Our maintenance policy ensures that we direct spending to the most important flood defences. In the longer term we can not continue to fund pumping stations that do not reduce the risk of flooding to property. These are Wilfholme, Hempholme and Tickton pumping stations. River Hull Flood Risk Management Strategy Report vii

14 The costs of maintaining some of the flood banks in the upper catchment are greater than the financial benefits of doing so. In situations where we can no longer justify long-term funding, we propose to provide funding for up to five years while we work with communities and partner organisations to explore options for alternative funding. Our proposed strategy We will continue to maintain and, in some areas, improve those flood banks, walls and other structures for which we are responsible and can obtain funding. This will require an investment of 109 million over the next 20 years and will protect the vast majority of people, property and agricultural land. We will continue to operate and maintain the Hull Barrier and our pumping stations at East Hull and Great Culvert. This will include work such as the 10 million investment currently underway at the Hull Barrier. We will work with Hull City Council and the owners of riverside land to develop a plan for repairing and improving the defences beside the River Hull through the city. We will continue to maintain and operate our other pumping stations for a period of up to five years while we work with the local authority, Internal Drainage Boards, landowners and others to find a longer term funding solution. We will continue to maintain the flood banks in the upper catchment for a period of up to five years while we work with East Riding of Yorkshire Council, Internal Drainage Boards, Natural England, landowners and others to develop a longer term plan for water level management in this area. We have produced a draft action plan to implement the Strategy. This is included in the draft Strategy and Strategy summary document. How to comment You can have your say on the draft Strategy by attending one of our events or sending us an or letter with your comments. You can view the draft Strategy documents including a summary document at: - Libraries at Hull Central, Beverley and Driffield; - in some East Riding of Yorkshire council and Hull city council Customer Service Centres; - some Environment Agency Offices. To find out more the consultation, including event and exhibition details or to obtain consultation documents visit our website or contact us on , riverhull@environment-agency.gov.uk River Hull Flood Risk Management Strategy Report viii

15 1. Introduction This section explains why we are developing a flood risk management strategy for the River Hull. It covers: our wider national vision, and how the Strategy can contribute to achieving its goals; the links to our wider work, which deal with flooding or other issues in the study area and the wider catchment; the aim and objectives of the Strategy; the reasons and benefits for taking a strategic approach to flood risk management; and the stages and timescales of the development of the strategy. 1.1 The Environment Agency vision We have a vision for the environment: a better place for people and wildlife, for present and for future generations. To achieve our vision, we will work towards the following five key areas, Key area Act to reduce climate change and its consequences Protect and improve water, land and air Work with people and communities to create better places Our aims We play our full part in helping England and Wales meet greenhouse gas emissions targets in ways that minimise other environmental impacts. We help people and wildlife adapt to climate change and reduce its adverse impacts. We put reducing and adapting to climate change at the heart of everything we do. The quality of surface, ground and coastal water and wetlands continues to improve for the benefit of people, the economy and wildlife. Land is managed sustainably; protecting soils, water and biodiversity and contributing positively to reducing and adapting to climate change. Biodiversity is enhanced and fish stocks are managed sustainably for the benefit of wildlife and people. Businesses and other organisations reduce the impacts of their activities on water, land and air and are responsible operators. We improve how we work as regulators to maximise environmental outcomes while minimising the cost to businesses. Flood risk and coastal erosion are effectively managed and people and property are better prepared and protected. Better local environments enhance people s lives and support a sustainable economy. New and existing developments have a reduced environmental impact and well-planned environmental infrastructure. All sections of society have opportunities to enjoy water and wetlands through angling, navigation, sport and other recreation. River Hull Flood Risk Management Strategy Report 1

16 Key area Work with business and other organisations to use resources wisely Be the best we can Our aims Businesses and other organisations know what the best environmental options are for managing waste and using resources wisely. The right waste and resource management infrastructure is in place. Businesses and other organisations are resource efficient, minimise pollution and manage their waste responsibly. Safe, secure water supplies are used efficiently to meet the needs of the public, business and the environment. We will provide a first class customer service. We will work effectively with partners to deliver shared environmental outcomes. We will use evidence and knowledge to guide and inspire our own actions and the actions of others. We will equip and train staff to achieve their potential and maximise their productivity. We will be acknowledged as leaders in managing our own environmental impact. We will make the best use of our funding to deliver more for people and the environment. 1.2 Creating a better place priorities and targets Our Corporate Strategy 1 sets out what we need to do over the five years ( ) to work towards our vision. We have called our Corporate Strategy Creating a better place. It identifies priorities for action under each of the five key areas of the vision. For each of these priorities we have set national targets against which we will measure our results over the next five years. For example, one of our priorities for work with people and communities to create better places is to ensure flood risk and coastal erosion are effectively managed and people and property are better prepared and protected. We have set a national target of our flood and coastal risk management programme delivering at least 5 of benefits for each 1 invested. We will deliver part of our Corporate Strategy at a national level, for example by advising the Government on policy. However, many of the improvements that we desire must be achieved at a regional and local level, where people and wildlife live. Each of our seven English regions and Environment Agency Wales has prepared a local contribution. This shows how each region will create a better place locally, and contribute to the five key areas of our vision. Our local contribution for north east region sets out the targets and actions that we aim to achieve as our contribution to the national targets. 1.3 Strategy policy links In autumn 2004, the Government set out its new national strategy for flood and coastal erosion risk management, called Making Space for Water 2. This applies the principles of sustainable development to flood risk management. It considers how we should adapt to future climate change and seeks ways to help all communities and individuals prepare for and live with flooding. 1 Our vision and our corporate strategy creating a better place can be obtained from Or telephone Our north east local contribution can be found at under north east corporate strategy or telephone Defra (2004), Making Space for Water Developing a new Government strategy for flood and coastal erosion risk management in England: A Consultation Exercise. Also, Defra (2005), The Government s first response to the consultation exercise : River Hull Flood Risk Management Strategy Report 2

17 Making Space for Water promotes an integrated approach to flood risk management. This means considering whole river catchments and adopting flood risk management measures that provide environmental, social and economic benefits. As far as possible, solutions will work with natural processes and make more space for water in the floodplain. This may involve restoring wetlands or setting development back from river corridors, for example. Making Space for Water aims for flood risk management to be undertaken in ways that contribute to the implementation of the European Water Framework Directive. Catchment Flood Management Plans (CFMPs) form the highest level of flood management planning. The draft Hull and Coastal Streams CFMP sets the proposed overall direction of flood risk management at the catchment scale for the next 50 to 100 years. The draft Hull and Coastal Streams CFMP is to be subject to further consultation at the time we consult on our draft River Hull Flood Risk Management Strategy. The draft CFMP presents our recommended policies for flood risk management for the whole River Hull catchment and other areas, and provides a framework for this Strategy. Working together with the CFMP, we are committed to developing a single, integrated plan for flood risk management in the River Hull catchment. This Strategy seeks to encourage co-operation and partnerships, and we have consulted with a wide range of organisations. By considering issues other than flood risk, such as biodiversity, land use and management, natural resources, fisheries, amenity and development, we may be able to achieve wider benefits. Some of the other plans that we have taken into account in developing the draft River Hull Flood Risk Management Strategy are described further in Section 2.4. Any construction of flood risk management measures recommended by the draft River Hull Flood Risk Management Strategy will be carried out under our powers under the Water Resources Act (1991), and will be subject to all necessary approvals and availability of funding. We will continue to consult and work in dialogue with other organisations and local communities as we implement these measures. 1.4 Strategy aims and objectives Our overall aim for the River Hull FRM Strategy is to provide sustainable flood risk management for people, properties and the environment within the River Hull catchment over the next 100 years. We We have defined strategic objectives which are in line with our vision to set out what we will do to deliver our overall aim, these are listed in Table 1.1 below. Table 1.1 Our objectives for the River Hull Flood Risk Management Strategy To develop a plan for the catchment s flood risk management that is sustainable, taking into account future changes in the environment (human, built or natural) and the climate. To ensure that all proposals are technically feasible, economically viable, socially acceptable and environmentally appropriate (by meeting the strategic environmental objectives). To work in partnership with and encourage co-operation between other organisations. To understand and raise awareness of the risk of flooding within the River Hull catchment, both now and in the future. To seek environmental enhancement opportunities wherever possible through the recommendation of integrated flood risk management measures. To seek, where possible, economic development and employment opportunities, including in the wider countryside through diversification, tourism and recreation. River Hull Flood Risk Management Strategy Report 3

18 1.5 Benefits of a strategic approach We have adopted a strategic approach to flood risk management in the River Hull to fit with the Government s integrated approach promoted nationally in Making Space for Water. By a strategic approach, we mean looking at a problem in a comprehensive way, for example: taking account of all associated impacts; considering the interests of other parties; and, evaluating the widest possible set of potential options. We have prepared this strategy in accordance with Flood and Coastal Defence Project Appraisal Guidance (FCDPAG) 3 published by the Department for the Environment Food and Rural Affairs (Defra). Volume 2 of this guidance sets out the framework for this Flood Risk Management Strategy. A revised Appraisal Guidance was issued in March 2010 and is a living draft until December We will continue to review our work in light of the new guidance to satisfy ourselves that the strategy meets any changed requirements. We first had to determine whether it was appropriate to take a strategic approach for the River Hull. The guidance from Defra provides examples of when such an approach is recommended. We have listed these in Table 1.2, together with specific reasons to demonstrate why a strategic approach is appropriate for the River Hull. We will refer to strategic options throughout this report; this means an option that will deliver flood risk management benefits to several areas. When is it appropriate to develop a strategy? When problems are widespread across the catchment. When there is an advantage in considering problems and solutions in the long term. When works will be carried out over a long timescale. When there are multiple areas which may benefit from a single option. When there are connections between different parts of the catchment and different sections of work. Table 1.2 Reasons for a strategic approach How is this relevant to the River Hull? We estimate there are around 100,000 existing properties in the study area that would be at future risk of flooding from a 1 in 100 (1%) AEP flood event, taking into account climate change. Approximately 99% of these are protected by purpose-built flood defences, although the standard of protection varies. Flood risk may change in the future due to climate change and changes in the catchment such as urban growth. Our Strategy will help us identify and plan for these impacts. This Strategy also allows us to work at the same level with, and therefore influence, other long term plans such as Development Plans. We aim to set out a sustainable approach to flood risk management for people, property and the environment over the next 100 years. Due to the widespread nature of the flooding problems, investment to tackle these will need to be planned over the long-term. The Strategy will help us to prioritise investment, reflecting existing levels of flood risk. The catchment is very flat and there are several low lying areas which naturally act as floodplain. Utilisation of these natural floodplains could benefit other areas within the catchment. Flooding in the River Hull catchment is influenced by factors including natural floodplain storage and the contribution of flow from many tributaries. We are aware that our actions in one part of the catchment could affect flood risk elsewhere, so we must use a strategic approach to identify solutions. 3 FCDPAG is a series of documents that set out best practice in the evaluation of flood defence projects, with a view to promoting a consistent approach to the management of flood risk. The principal guidance document used for developing a flood risk management strategy is MAFF(2001), FCDPAG2: Strategic Planning and Appraisal. River Hull Flood Risk Management Strategy Report 4

19 When is it appropriate to develop a strategy? When several small problems can be tackled together. When environmental or other implications extend beyond the immediate area of a scheme. When there is the potential to achieve wider opportunities. How is this relevant to the River Hull? There are a number of distinct communities at risk of flooding along the course of the Hull and its tributaries, as well as interconnected flood risk areas. Considering flooding problems in an integrated way allows us to assess the impact of options across a wide area. An integrated study enables us to better understand the wider implications of the various approaches to flood risk management, in terms of their potential environmental impacts (positive or negative), as well as their effectiveness in reducing flood risk. For example, we look at the potential to improve the connectivity of river and wetland habitats along the Hull and its tributaries. The Strategy enables us to explore links and opportunities between flood risk management, environmental and amenity improvements, development planning and economic regeneration within a river basin context, bringing several local authority areas together. Consequently, a strategic approach to flood risk management in the River Hull catchment has been adopted. The benefits of a strategic approach include improved long-term planning of flood risk management and improved ability to work with natural flooding processes. We can also identify and achieve wider social and environmental opportunities, working in partnership with others. We have a target that all flood risk management projects will be identified through strategy studies or strategic thinking. 1.6 Strategy development and review The stages in the development of this Strategy are illustrated in Figure 1.1. This is our recommended Strategy which is published, in draft, with the Environmental Report for consultation so that individuals and organisations, who have an interest in the study area, can comment. We will consider all comments received during the consultation period and, where appropriate, amend our plan to address them. The requirements for flood risk management will almost certainly change over time. In addition, our knowledge of the processes within the study area and wider catchment will increase. To reflect this changing environment, we will review and update the findings of this strategy every five years or as appropriate to reflect changes in flood risk management policy, for example. River Hull Flood Risk Management Strategy Report 5

20 Figure 1-1 Stages in the development of the River Hull Flood Risk Management Strategy Flooding and environmental problems examined and better understood, including the potential future impacts of climate change Potential options developed and evaluated to form a shorter list of feasible options. Consultation undertaken to agree the key issues to be considered when assessing the impact of the options on the environment. (Scoping Stage). Scoping report produced in May Comments received from consultees during the ongoing development of the strategy. Options assessed for technical feasibility, their impact on the environment, and for economic viability. Consultation workshops held to gain views on appraisal process. Where we are now Our preferred Strategy and Environmental Report will be published in draft for consultation and includes: Recommendations for short, medium and long-term investment in flood risk management Recommendations for further studies/detailed appraisals Other recommendations to achieve long term success in managing flood risk River Hull Flood Risk Management Strategy The Strategy is a live document which will be reviewed approximately every 5 years or as appropriate, for example, to reflect major policy changes. River Hull Flood Risk Management Strategy Report 6

21 2. Catchment overview This section describes the River Hull Flood Risk Management Strategy study area. It includes: a brief description of the catchment of the River Hull, its tributaries and associated drainage system, and a definition of the boundary of the River Hull study area; a summary of the environmental issues, drawing on the Strategic Environmental Assessment process; details on how the study area is divided up for the purposes of identifying and assessing flood risk and flood risk management options; an explanation of the links with other plans and policies, and where these may provide opportunities or present constraints. 2.1 The River Hull catchment and definition of the study area The study area The River Hull FRM Strategy location and study area is shown in Figure 2-1. The study area covers approximately 980km 2, with the Yorkshire Wolds to the west and north and the Humber Estuary to the south. The main catchments within the study area are the River Hull and the Holderness Drain catchments. These catchments fall within the administrative areas of Kingstonupon-Hull City Council, East Riding of Yorkshire Council and a small area of Ryedale District Council/North Yorkshire County Council. Kingston-upon-Hull is the main urban centre within the study area. Other settlements within the catchment include the market towns of Beverley and Driffield as well as many small villages. Table 2.1 provides a summary of the key physical and environmental features of the Strategy area. This should be used as an approximate overview of the catchment, the derivation of the at risk of flooding values is discussed in Section 3.5. Watercourse Average annual rainfall Geology Urban areas Table 2.1 River Hull Strategy area overview 233 km designated as main rivers Between 625 to 825mm Chalk underlies most of the River Hull Strategy area; away from the Wolds the chalk is buried under a layer of glacial deposits. Kingston-upon-Hull, Beverley, Driffield Assets Total for Strategy area At Risk of flooding* At risk of flooding (%)* Population 386, , Area 980 km km 2 16 Agricultural grade land (1-3) 858 km 2 96 km 2 11 Residential properties 165,000 99, Motorway 0.0 km 0.0 km - A-class roads 202 km 30.5 km 15 Railway 56.7 km 13.8 km 24 Canals 13.3 km 7.5 km 56 Sites of Special Scientific Interest (SSSIs) (ha) 415 ha 66 ha 16 Schedule Monuments (SMs) (number) River Hull Flood Risk Management Strategy Report 7

22 * Based on 1% Annual Exceedance Probability (AEP) fluvial flood extent for the River Hull and Holderness Drain system if flood defences are not present (based on future climate), this does not include smaller areas of more localised flooding on smaller tributaries away from the main river valley Topography Figure 2-1 Strategy location and study area Topography has a direct impact on flood risk through its influence on catchment response to rainfall. Steeper slopes tend to cause a faster speed of flow, both below and over the ground surface. Topography also influences the extent of flooding as in flat areas floodwaters can spread over much larger extents than in narrow valleys. This is particularly relevant in the River Hull Strategy area. The land in the River Hull Strategy area rises from mean sea level (or just below) to nearly 250m above sea level (see Figure 2-2). The highest land is in the Yorkshire Wolds, which run in an arc across the north and west of the catchment. The topography of the Wolds is typical of chalk landscapes with a gently rolling plateau that falls gently eastward towards the low flat area of River Hull Flood Risk Management Strategy Report 8

23 Holderness. A complex network of often steep-sided and deep valleys run out of the Wolds to the low lying areas. Away from the Wolds the remainder of the River Hull Strategy area is dominated by flat and low lying land. Much of this land is only just above mean sea level. The River Hull has almost no slope in the middle and lower reaches and the tidal influence extends up to Hempholme Weir 30km upstream of the Humber. Figure 2-2 Topography of the Strategy area The river system The River Hull is fed by a number of springs and becks within the Yorkshire Wolds, which join together south of Driffield. The river flows through open countryside before it skirts past the eastern edge of the town of Beverley and reaches Kingston-upon-Hull. It flows through the centre of the heavily populated and industrial area of the City of Kingston-upon-Hull before joining the Humber estuary at Victoria Pier near to The Deep and the Tidal Surge Barrier. The River Hull is River Hull Flood Risk Management Strategy Report 9

24 embanked for most of its length, in some places the embankments are over 5m high and the bed of the river is above the level of the surrounding land. The River Hull s main tributaries are West Beck, Kelk Beck, Old Howe, Frodingham Beck, Driffield Beck, Skerne Beck, Nafferton Beck, Scurf Dike, Mickley Dike, Watton Beck and Catchwater Drain/Arram Beck. Together with the River Hull, these form the River Hull high level system. The numerous drains in the low lying land predominantly to the west of River Hull, including Beverley and Barmston Drain form the River Hull low level system. Holderness Drain is not a tributary of the River Hull but is an important part of the drainage network in this area as it discharges flows from areas to the east of the River Hull directly into the Humber estuary. Similarly to the River Hull, Holderness Drain comprises a high level and a low level system. Monk Dike, Catchwater Drain, Bowlams Dike and the lower part of Holderness Drain form the Holderness Drain high level system. The numerous drains in the low lying land to the east of River Hull, including the upper and middle parts of Holderness Drain form the Holderness Drain low level system. The embankments on the Holderness Drain high level system are much lower than those on the River Hull high level system, typically 1 or 2m high compared to 4m high. Many of the river systems are complex due to a long history of modification. The response of the catchment to extreme rainfall is also complex because of the interaction of ground and surface water as well as the large tidal influence of the Humber Estuary. Figure 2-3 Upper River Hull from Wansford Bridge River Hull Flood Risk Management Strategy Report 10

25 Figure 2-4 Lower River Hull through Kingston-upon-Hull Most of the land adjacent to the river is low lying, including the majority of the City of Kingstonupon-Hull and significant parts of the East Riding of Yorkshire, and would suffer from frequent flooding without the presence of a variety of flood defences. This low-lying area is typically at risk from both fluvial and tidal flooding although in the north of the catchment, the risk is just from fluvial flooding. Coastal flooding, i.e. flooding directly from the Humber, is covered by the Government approved Humber Strategy. The River Hull FRM Strategy focuses on fluvial flooding in the inland parts of the catchment. A map of the various key components of the River Hull and Holderness Drain system is shown in Figure 2-5. The River Hull Tidal Surge Barrier, at the mouth of the River Hull, can be used to prevent surge tides overwhelming river defences. At the mouth of Holderness Drain and where Beverley and Barmston Drain, Scurf Dike and Watton Beck enter the River Hull, structures are installed which prevent reverse flow up the channels causing flooding. The figure also shows the pumping stations on the River Hull system. It should be noted that the River Hull high and low level systems are only connected at Wilfholme, Waterside and Hempholme Pumping Stations (PS) and High Flags outfall. On Holderness Drain, Tickton PS and Great Culvert PS pump flows along the drain to enable it to discharge into the Humber estuary. Great Culvert PS connects the Holderness Drain high and low level systems. East Hull PS can be used to pump flows into Humber estuary during high flows when the tide is too high for Holderness Drain to discharge. We are spending 900k on refurbishment of East Hull PS and also have a project underway looking at the best way of providing pumping capacity at East Hull PS into the future. River Hull Flood Risk Management Strategy Report 11

26 Figure 2-5 Key features of the River Hull system 2.2 Environmental context This section outlines the main strategic features of the natural and human environment within the River Hull catchment. You can find further details in the Strategic Environmental Assessment (SEA) Environmental Report in Appendix B of this Strategy People and property The main centre of population is the urban area of Kingston-upon-Hull where approximately 243,600 people live in the city, in 104,300 households (2001 census). The area is a major focus for jobs, commercial interests, services and facilities, and has diversified into smaller industries to replace the loss of the fishing industry. High profile industrial and residential areas are also being developed to attract people to the city. Most of the city lies in the indicative floodplain. River Hull Flood Risk Management Strategy Report 12

27 Smaller market towns of Beverley and Driffield (with population levels of about 25,000 and 11,000, respectively), and a number of villages e.g. North Frodingham, Leven and Wansford are within the study area. Beverley and Driffield have experienced significant growth over recent years, with new housing increasing commuters Land use and landscape Land form in the study area is generally low-lying and flat, which creates a broad and shallow river valley that is only perceptible on a local scale. The flat landscape offers few natural barriers to the flow of flood water on the floodplain. Trees and hedgerows are generally sparse, as agricultural improvement has led to the loss of most areas of semi-natural vegetation. There are smaller areas of pasture and parkland towards the towns of Beverley and Driffield. Greater coverage of vegetation is found to the north of the catchment, with plantations on the lower slopes of the Yorkshire Wolds. Much of the study area is in agricultural use; the Agricultural Land Classification of the land is mostly grade 2 (very good, 55%) and grade 3 (moderate, 42%), with small areas of grade 4 (poor, 3%) and non-agricultural land. Most of the holdings are large-scale, mixed arable cultivations with some intensive livestock farming. Kingston-upon-Hull is a major urban area, with industrial, commercial and residential land use. There are also large areas of contaminated/derelict land in Kingston-upon-Hull Recreation and amenity There are various sites that are important for formal and informal recreation and tourism in the study area, for example nature reserves such as Tophill Low, and disused gravel pits where sailing and fishing now takes place. Recreational activities along the River Hull include walking, bird watching, boating and fishing. There is a network of public footpaths including the regional Trans-Pennine Trail. To the south of the study area, a green network of footpaths and cycleways link the settlements in this area. The River Hull is navigable for leisure craft from Hull to beyond Beverley, along spurs to Corps Landing, Brigham and North Frodingham (freight can only go as far as Beverley). The Driffield Navigation Trust has been undertaking various restoration works to locks on the Driffield Canal for recreational usage Material Assets There are a number of transport routes in the study area, linking the urban centre of Kingstonupon-Hull and other settlements, and linking these to urban areas outside of the study area. The main east-west route is the A63(T), and this forms the boundary between the River Hull FRM Strategy and the Humber Estuary FRM Strategy study areas. The A63(T) links Kingston-upon-Hull with Manchester and Leeds via the M62, and the A1033. North-south connections are provided by the A1079(T), A165, A1035 and A164. A rail link connects Driffield and Beverley to Kingston-upon-Hull. The River Hull is navigable for freight barges through Kingston-upon-Hull, as far as Beverley, with wharf facilities along the river in Hull and Beverley. The river connects to the busy commercial waterway of the Humber Estuary, and this provides access to the international ports of Hull (and others around the estuary), which are of prime importance to the regional and national economy Natural environment The whole of the Humber Estuary, which abuts the southern boundary of the study area, is internationally and nationally designated for its nature conservation importance (Site of Community Importance (SCI); Special Protection Area (SPA); Ramsar site; and Site of Special Scientific Interest, (SSSI)). There are no National Nature Reserves within the study area. There are 15 SSSIs within the study area. Of these, four are in or immediately adjacent to the River Hull corridor: River Hull Flood Risk Management Strategy Report 13

28 The River Hull Headwaters are designated as the most northerly chalk stream system in Britain, and include adjacent remnants of ecologically important habitats, such as riverside wet grassland, woodland and fen. Tophill Low consists of two artificial storage reservoirs 10km south west of Driffield. The site is one of few inland standing open water bodies in the sub-region suitable for wintering wildfowl. Pulfin Bog is 16.8 Ha of the last remnants of a fenland reed swamp community in the Hull Valley, with botanical and ornithological interest. Leven Canal is a is 5km length of canal which cuts across marshland and meres of the Hull Valley, and following drainage of the surrounding land, is now a refuge for wetland plants. The water is fed by calcareous springs and is of very high quality. The following priority species in the study area have been identified as requiring protection and enhancement nationally by the UK Biodiversity Action Plan (BAP) short list Fisheries otter and water vole - we are the lead partner for otter and water vole UK BAP species plans, and for the chalk rivers habitat plan; great crested newt; The River Hull Headwaters are recognised as a valuable salmonid/fly fishery, with the main species in these upper reaches being brown trout, grayling and pike. A good coarse fishery is supported in the middle and lower reaches of the Hull, which are more embanked and canalised with some saline influence, and in the agricultural drains and ditches where flows are slower. Species include perch, roach, gudgeon, dace, chub, bream and occasional flounder upstream of the confluence with the Humber. Eels are found throughout the system but in common with most of Europe, populations are believed to be a small fraction of their historic levels, Cultural heritage There are no World Heritage Sites in the study area. There are a significant number of Scheduled Monuments (16 of which are within 1km of the River Hull), which are nationally important and protected by law. Many of the existing settlements, for example Beverley, are Medieval in origin, and there are several settlements that failed and became deserted. These are mainly located in the headwaters but also extend as far south as Eske near Beverley. There are five Registered Parks and Gardens of Historic Interest wholly or partly in the study area, as listed below. East Park, Hull Grade II; registered April 2001; 48.64ha. Pearson Park, Hull Grade II; registered April 2001; 9.41 ha Risby Hall - Grade II; registered March 1999; 33.31ha. Dalton Hall Grade II*; registered May 1984; ha. Sledmere House Grade I; registered May 1984; ha. The Conservation Areas wholly or partly within the study area are listed below, Hull City contains 21 Conservation Areas, covering 6% of the city; 2 of which, Charterhouse and Old Town, are in the immediate vicinity of the River Hull corridor. Beverley Borough - Beverley, Bishop Burton, Lockington, and Walkington; River Hull Flood Risk Management Strategy Report 14

29 2.2.8 Water Holderness District - Aldbrough, Bewholme, Brandesburton, Seaton, Dunnington, Hatfield, Sigglethorne and Swine East Yorkshire Borough - Kilham, Cranswick, Hutton, Driffield (one covering North of town centre and market area, one covering south of town centre including upstream end of Driffield Canal), Nafferton, Garton on the Wolds, North Dalton and Wetwang. There are 1296 Listed Buildings in the study area. Of these, 36 are Grade I, 77 Grade II*, 1171 Grade II and 12 De-Listed. Listed Buildings are concentrated in Hull, Beverley and Driffield, with smaller clusters associated with Conservation Areas in Nafferton, Lockington, Bishop Burton, and Walkington. There is an Area of Archaeological Importance identified in the Hull Local Plan. There is also known to be a high density of heritage features and archaeological remains within the Hull valley, many of which are unusually well preserved. Therefore, there are likely to be other historic environment assets that are, or could be, considered significant. There has been a long history of modifying the rivers within the catchment mainly to improve drainage so the catchment now is a network of largely artificial channels contained within embankments, often above the surrounding land, and low lying drainage channels. Only sections of river on the higher ground are in largely natural channels. The higher ground to the north and west is mainly chalk which has a major influence on water in the catchment. Rain easily soaks into the ground where it remains as groundwater. Where the level of groundwater is higher than the surrounding land it emerges as springs which feed the headwater streams and the main river. River levels in these chalk rivers are generally steady and rarely rise or fall quickly after rain. Most of the low lying ground is formed of poorly draining soils overlying the chalk and rain water mainly remains on the surface until it reaches the network of drains. Water from the chalk springs is usually very high quality, but as the rivers flow to the sea, water quality is influenced by fertilisers and agricultural chemicals, discharges from sewage works, fish farms, businesses, drainage from urban areas and finally, tidal water. Water quality in the low lying drains is moderate to poor. As the quality and quantity of groundwater is high, there are several abstractions for drinking water and spray irrigation. Water is also abstracted from the river at several locations for fish farming, drinking water, spray irrigation and industrial use. Under the Water Framework Directive, we published River Basin Management Plans for the whole of England and Wales in December This gives us a new way of measuring the quality of the water environment, in which we have to consider the chemical, physical and biological quality of each separate waterbody. The Directive requires us to identify the current condition and establish actions to restore natural waters to good ecological status and heavily modified or artificial waterbodies to good ecological potential by 2015, or later where this is not practical. The River Hull forms part of the Humber River Basin District. Of the 40 waterbodies (lengths of river, drain, or canal) in the Strategy study area, the majority (32) are classified as artificial or heavily modified The Humber River Basin Management Plan sets out what we and others will do to improve the quality of waterbodies across the whole district. We have assessed how the Strategy might influence how these actions are carried out in this catchment. 2.3 Definition of catchment areas One of the main benefits of developing a flood risk management strategy is that we can consider flooding processes in the study area as a whole, and understand how actions or changes in one part of the catchment may affect flooding in another area upstream or downstream. However, for some of our analysis we have divided the River Hull and its floodplain into 3 catchment areas, to River Hull Flood Risk Management Strategy Report 15

30 allow us to evaluate flood risk and possible alleviation measures at a suitably detailed level. The River Hull catchment areas are illustrated in Figure Lower catchment area Figure 2-6 River Hull catchment areas The lower catchment area covers the River Hull from the northern city limits of Kingston-upon- Hull, just downstream of Wawne on the east side of the River Hull and downstream of the B1233 / A1165 on the west side of the River Hull, to the Humber Estuary. The River Hull is embanked down to the industrial estate at Vulcan Road from which point the river s defences become a mixture of concrete and timber walls. This area also includes the downstream reaches of Beverley and Barmston Drain and Holderness Drain where they outfall to the River Hull and Humber, respectively. These reaches and the River Hull are far more influenced by the tide than by fluvial flows in this area. The tidal surge barrier is dropped into the river during high tidal surges to protect parts of the city from flooding. The barrier is raised when tide levels have dropped enough to allow the river to discharge to the estuary. River Hull Flood Risk Management Strategy Report 16

31 This area is predominantly urban and generally has a lower risk of fluvial flooding than the upper and middle catchment areas Middle catchment area The middle catchment area covers the River Hull from Hempholme Weir down to the city limits of Kingston-upon-Hull, just downstream of Wawne on the east side of the River Hull and to the B1233 / A1165 on the west side of the River Hull. The River Hull is heavily embanked through all of the middle catchment area with embankments 5m higher than surrounding ground levels in places. This area also includes the two major drains in the study area, Beverly and Barmston Drain and Holderness Drain, which both start near the northern boundary of the middle catchment area and flow in a southerly direction through to the lower catchment area. The River Hull and Beverley and Barmston Drain are tidally influenced in this area and the Holderness Drain is influenced by pumping. The middle catchment area contains the lowest lying land in the whole study area; the largest of which is Leven Carrs where ground levels are typically -0.5 to 0.0m AOD. This land is drained by Holderness Drain, which is pumped at Tickton and Great Culvert to maintain gravity discharge into the Humber. The middle catchment area includes the Orchard Park area of Kingston-upon-Hull, which lies between the A1079 and B1233 roads to the west of the River Hull. We have included this urban area because the flood risk here, particularly in the future, is influenced by the flood risk from Beverley and Barmston Drain further upstream due to the drain culverts through the A1079 road embankment. Including this urban area within the middle catchment area enables the full economic benefits of flood risk management options in the upper and middle areas to be properly considered Upper catchment area The upper catchment area covers the River Hull Headwaters down to Hempholme Weir. In this area the chalk streams and becks of the headwaters combine into the West Beck reach of the River Hull near Driffield and Frodingham Beck further east. The upper reaches of the River Hull are not embanked because the surrounding ground is naturally higher. The River Hull starts to become embanked approximately 2km downstream of Wansford as the surrounding ground levels drop below 5m AOD. Further downstream, the surrounding ground levels drop to less than 0.5m AOD in places, therefore the embankments of the River Hull and Frodingham Beck can be up to 4m high. The lowest lying land in this area is the North Frodingham Carrs where ground levels are typically 0.25 to 0.5m AOD. This land is mainly drained by Roam Drain, which flows under the River Hull and into the top of Beverley and Barmston Drain near Hempholme Weir. Water in Roam Drain can also be pumped into Mickley Dike at Hempholme pumping station. The rivers and drains in the upper catchment area are generally not tidally influenced beyond Hempholme Weir only a small influence is felt during floods. The southern embankments of Scurf Dike and Mickley Dike form the boundary between the upper and middle catchment areas Connectivity Although the three Strategy catchment areas have different characteristics, they are hydraulically connected in several places. This means that flooding in one catchment area can cause flooding in another. The main connections between the three catchment areas are: Main watercourses that flow between catchment areas, these include the River Hull, Beverley and Barmston Drain and Holderness Drain Smaller drains such as Engine Drain, which flows between the middle and lower catchment areas and Nafferton Drain, which flows between the upper and middle catchment areas connecting the floodplain in the Upper catchment area with Beverley and Barmston Drain. River Hull Flood Risk Management Strategy Report 17

32 Natural low ground between the middle and lower catchment areas, where water could flow during a flood. Flood risk management measures in parts of the River Hull system could produce environmental, social or economic impacts that extend into other areas of the study area due to the interconnectivity of the system. Where necessary, these wider consequences have been considered in our options appraisal. 2.4 Links to other plans opportunities and constraints This section explores opportunities and constraints that could arise from other studies, strategies and plans. (See Section 1.4 for links with these other plans). Opportunities and constraints that relate to particular flood risk management options are discussed further in Section 4. Flood Risk Hull and Coastal Streams Catchment Flood Management Plan As noted in section 1.4, the draft Hull and Coastal Streams CFMP sets out our policies for the long-term management of flood risk in the whole of the River Hull catchment. In the CFMP, recognition of our strategy areas has been used to help determine policy unit areas. However, because the upper and middle strategy areas are so closely linked, these two areas have been combined to form one policy unit. The recommended policies for the River Hull Strategy area have been developed in conjunction with the findings of the draft strategy and are presented in the following table and further described below: Table 2.2 Hull and Coastal Streams CFMP Policy units and preferred policies Policy Unit Preferred Policy Upper and Middle Hull Lower Hull P3 P5 P1. No active intervention- no active intervention (including flood warning and maintenance), but continue to monitor and advise. We could select this policy for natural catchments where the river is connected to the floodplains and flooding has beneficial effects for habitat. P2. Reduce existing flood risk management actions- reduce existing flood risk management actions (accepting that flood risk will increase over time). We may select this policy where the current and future risks in all or part of these areas do not warrant as much intervention (for example on maintenance) and we can allow the risk of flooding to increase naturally over time. P3. Continue with existing or alternate actions to manage flood risk at the current levelcontinue with existing or alternative actions to manage flood risk at the current level. We may select this policy where the risks are currently managed appropriately and where the risk of flooding is not expected to increase significantly in the future. P4. Take action to sustain the current scale of flood risk into the future- take further action to sustain the current level fo flood risk into the furure (responding to the potential icreases in risk from urban development, land use change and climate change). We could use this policy where the risks are deemed to be currently managed in an appropriate manner, but where the risk of flooding is expected to significantly ris in the future. In this case we would need to do more in the future to reduce the increases in risk. P5. Take further action to reduce flood risk- take further action to reduce flood risk. This policy is about reducing the flood risk in areas where the existing flood risk is too high. We need to take action in the short term to reduce this level of risk. Alternatively it may be about reducing flood risk in locations where the future flood risk is high. We will need to take longer term action to recude flood risk in these locations. River Hull Flood Risk Management Strategy Report 18

33 P6. Increase the frequency of flooding to deliver benefits locally or elsewhere- fthe aim of this policy is to attenuate water in those parts of the sub-area where there are multiple benefits from doing so. This could include storing water in part of the catchment in order to reduce flood risk to downstream communities. Alternatively it could include reducing run-off, restoring floodplains and improving habitats that contribute to reduce risk elsewhere. These policies recognise that there are many areas within the Hull and Coastal Streams catchment where existing (and potential future) flood risk to people, property and the built environment is a concern. The River Hull FRM Strategy is one of the first steps in taking further action. It provides a more detailed understanding of the nature and extent of the flood risk, and proposes our preferred measures for tackling flooding Other studies Within the strategy area the Environment Agency are currently working on a flood alleviation scheme at Western Drain, where in June 2007 heavy rain resulted in flooding to a large number of properties in Hessle and the tragic loss of a life. We are also carrying out a 10 million refurbishment of the Hull Tidal Surge Barrier and spending 900k on a refurbishment of East Hull Pumping Station. We also have a project underway looking at the best way of providing pumping capacity at East Hull pumping station into the future. Other organisations in the catchment are also involved in managing flood risk. Other flood related work being carried out in the strategy area includes the following: Surface Water Management Plan (SWMP) (Kingston-upon-Hull): this study was led by Hull City Council with involvement from a number of partners including Yorkshire Water, the Environment Agency, ERYC and Halcrow. The SWMP identified areas at highest risk of surface water flooding, and developed mitigation solutions. The objective of this project was to provide a long-term strategy for the City of Hull s surface water management including an action plan. The use of Aqua Greens (dual purpose public recreation and surface water storage areas) were considered alongside other options. Hull City Council Aqua Greens Feasibility (Kingston-upon-Hull): this project leads on from the first two items on the SWMP action plan and is to look at the feasibility of providing aqua greens to mitigate flooding (specifically surface water flood risk) for two areas in the city Hull Flood Mitigation Investment Plan: this project is being led by Hull City Council in conjunction with the Environment Agency, Yorkshire Water, ERYC and Halcrow. The objective is to review all sources of flood risk (fluvial, pluvial, coastal, sewerage and groundwater) in the Hull and Haltemprice catchment (much of our lower catchment area), identify and evaluate mitigation options, identify existing and potential sources of funding and produce a programmed flood mitigation investment plan. East Riding Flood Review (East Riding of Yorkshire Council): following the flooding during June and July 2007 East Riding carried out a flood review to identify the source and potential causes of flooding. As a result of this review a number of potential improvement projects were identified and are currently being investigated further. Our partners in the local authorities, Yorkshire Water, and Internal Drainage Boards in rural areas have been involved in developing this Strategy. This has helped to identify interactions between sources of flooding, and the constraints to solving the problems. Constraints include the limited budget available for sewer and drainage improvement works. In Yorkshire Water s case, investment is restricted by the price limits for water services imposed by Ofwat. There are important opportunities for the Environment Agency, Yorkshire Water and local authorities to work together to find the most effective solutions to flooding, particularly where flooding from drains, watercourses and surface run-off interact. These detailed solutions will not be identified within this high level strategy, which only deals with river flooding. However, they will be included in subsequent design of flood management schemes for local sites. River Hull Flood Risk Management Strategy Report 19

34 2.4.3 Planning and development The majority of the study area falls within East Riding of Yorkshire Council, with Hull City Council covering the urban area of Hull. A very small area to the north west of the study area falls within the administrative boundary of Ryedale District Council and North Yorkshire County Council. These local authority boundaries are shown in Figure 2-7. Figure 2-7 Local Authority boundaries in the River Hull Strategy study area The existing statutory development plan for East Riding of Yorkshire and Kingston-upon-Hull Unitary Authorities is the adopted Joint Structure Plan (JSP), which functions as a Joint Core Strategy for both authorities until it is reviewed and replaced as part of the Local Development Framework (LDF). The JSP sets the framework for the development and use of land up to 2016 in the combined area of Hull and the East Riding of Yorkshire. East Yorkshire Borough, Beverley Borough, Boothferry and Holderness District Councils were amalgamated when the East Riding of Yorkshire Council was created in April 1996, but their Local Plans are still in force, as is the Local River Hull Flood Risk Management Strategy Report 20

35 Plan for Hull City, until the East Riding LDF and the Hull City LDF are adopted. In addition, the Yorkshire and Humber Regional Spatial Strategy (RSS) provides the higher level strategic framework for planning decisions, and all Local Plans must conform to this. We have considered these plans, as well as the RSS, in developing this Strategy. The Local Plans and the JSP will eventually be replaced by the emerging LDFs for both East Riding of Yorkshire and Kingston-upon-Hull. The LDFs will be made up of various Development Plan Documents (DPDs) and Supplementary Planning Documents (SPDs), with the stages of adoption varying between the two authorities. The relevant LDF documents in the study area have yet to be adopted and are at the early consultation stages, although Hull is close to adopting its City Centre Area Action Plan (AAP). The AAP contains proposals for environmental enhancements, economic and retail regeneration and residential development in the city centre of Hull. Given the focus of development in the urban area of Hull we have considered the implications of the proposed development and potential concurrence between the emerging spatial plans and the flood risk management options recommended by this Strategy. Some of the opportunities and constraints are described below. Opportunities greater awareness of flood risk Both regional and local development plans take direction from national government Planning Policy Statement PPS25 - Development and flood risk. This states that the potential for flooding of land is a significant consideration in the planning process. A sequential risk-based approach is set out for determining whether new development is appropriate in areas prone to flooding. To assist with testing the suitability of sites at flood risk, local authorities are encouraged to carry out Strategic Flood Risk Assessments (SFRA) for their area. Hull City Council has completed its SFRA and it is available on the Council website, the SFRA was produced in close collaboration with Yorkshire Water, the Environment Agency and East Riding of Yorkshire Council, to enable a thorough and detailed understanding of flood risk to be presented, along with some recommendations to minimise these risks. East Riding of Yorkshire Council is currently reviewing its SFRA (2002) and it is expected to be published some time in Following the principles set out in PPS25, the Yorkshire and Humber RSS states its preferred approach for development to occur outside the Flood Zone (areas of flood risk defined by PPS25). As the RSS guides the formulation and development of the Local Plan in the study area the emerging LDFs will follow this philosophy. We have updated our Flood Zones for the River Hull using information from the assessment of flood risk carried out for this Strategy (see section 3.5) and for the Hull SFRA. Flood Zones are maps showing areas at risk from flooding, which are used by local authorities for development planning purposes. Opportunities and constraints previously developed land in the floodplain The adopted statutory development plans, as well as the emerging LDF documents, identify a priority to develop land that has been previously developed on in order to create sustainable and unified central urban areas. New development will use the sequential approach to development in order to focus development away from areas at risk from flooding. This creates the opportunity to utilise existing Flood Zones, and to some extent open space and green infrastructure, for flood management purposes. This has the added benefit of preventing new building being placed at risk of flooding whilst providing more space for floodwater together with wildlife and recreation corridors. This may ultimately reduce flood levels elsewhere. Whilst the focus of development is within principal towns, urban centres and settlements, there is pressure for significant development in the region from the local and regional development strategies. This pressure for regeneration, particularly in terms of the economy, forms a significant constraint on the Strategy. For example, the Joint Structure Plan does not rule out the possibility for urban extensions which may require the release of green field land, which makes up a large amount of the Flood Zone. The Hull Local Plan provides particular focus for urban regeneration on the river corridor which is listed as a strategic regeneration site (and includes the Kingswood area). Where development in the Flood Zone is essential, we are encouraging planners and River Hull Flood Risk Management Strategy Report 21

36 regeneration agencies to fully consider the implications of flood risk and design appropriately as well as leave a strip of land adjacent to the river. We also have powers under our land drainage bye-laws to prevent building within this strip. This provides space for flood flows or for construction and maintenance of flood defences. Such strips of land may have added benefits as a wildlife corridor or for walking and cycling along the waterfront. The recently adopted Hull SFRA and the review of East Riding s SFRA is an opportunity to influence the expansion of areas designated as functional floodplain. We are also exploring the scope of negotiating planning contributions, as well as other means, with developers on brownfield sites in the floodplain. This would require the developer to contribute to investment in flood risk management at their sites or elsewhere in the catchment; this is particularly relevant with the recent publication of the Community Infrastructure Levy (CIL). Opportunities and constraints environmental enhancement and protection Planning policy, particularly within Kingston-upon-Hull, places great emphasis on the River Hull corridor and the Humber estuary for the focus of environmental improvement and, particularly in the case of Hull city centre, the location of waterfront development. For example, the Hull Local Plan identifies the River Hull corridor as an Area of Potential Change with the potential to develop the waterfront with emerging economic development such as office, residential and leisure development. This principle has been carried forward into the emerging City Centre AAP and Core Strategy for Hull. The potential to utilise flood management works for environmental improvements is recognised in the Joint Structure Plan, which states that environmental management methods will be promoted where possible to reduce the risk of flooding and enhance biodiversity by creating new habitat and protecting the integrity of existing watercourses, washlands and land drainage systems. It is also identified in the Hull Local Plan that the urban green space forming river corridors and other waterside areas will be protected from development and their improvement supported. The Strategy can help to protect and enhance existing green corridors along the River Hull (for example by creation of wildlife habitat and leisure facilities) by providing protection against flooding. Given the focus of Hull s regeneration around the waterfront, the need to work in partnership with this regeneration is key; therefore there are potential opportunities to develop flood management schemes as part of the waterfront improvements in the study area. This approach should be taken throughout the catchment area, should the opportunity arise. Constraints local planning policies and the historic environment Local development plans may restrict our options for flood risk management schemes through policies that protect designated nature conservation sites, Scheduled Ancient Monuments, Conservation Areas, and Historic Parks and Gardens. The development limits of local planning policy and proposed development, in the green belt and on the waterfront in particular, may restrict the flood risk management in the study area. Constraints key transport movement The Joint Structure Plan designates strategic public transport corridor and multi-modal freight transport corridor which follows the River Hull. This designation may restrict a flood risk management scheme in that it will restrict the options which may impact upon the operation of these key transport corridors Environmental Issues There are many strategies and plans, both national and local, which consider environmental issues. There are both opportunities and constraints in linking these plans with flood risk management. The key strategic issues and opportunities identified for the Strategy study area are listed below, and these are the issues that have shaped our Strategic Environmental Assessment (SEA). Safety, security and well-being of the population Properties and material assets in the floodplain Proximity of Humber Estuary, which is of international importance for nature conservation River Hull Flood Risk Management Strategy Report 22

37 Sites of Special Scientific Interest (SSSI) located close to the River Hull; and the opportunity to improve their condition Opportunities to create new habitats, particularly wetlands or green corridors Good quality agricultural land Industry and port facilities in Kingston-upon-Hull, and the opportunity to improve Brownfield sites Scheduled Monuments and Listed Buildings in the study area Recreation and amenity facilities in the study area. Opportunities for better access to the riverside with footpaths and cycle ways, opportunities to create recreational corridors ( linear parks ) that link in to national networks Maintaining water quality, and minimising pollution We have identified the following strategies and plans that are relevant to the key strategic issues, where there might be opportunities or constraints. However, the potential for any opportunities to be delivered is dependent on the combination of Strategy elements and the preferred Management Approach. UK Biodiversity Action Plan (BAP), Hull Local BAP and East Riding local BAP - The UK BAP is the UK s initiative to maintain and enhance biodiversity (the variety of flora and fauna). BAPs are also prepared at a local level. There could be opportunities associated with UK / local BAP habitats and species through the delivery of the River Hull FRM Strategy, or constraints where the Strategy may not assist with BAP targets. However, these opportunities or constraints have not been considered at the Strategy level, and would need to be considered as part of project level Environmental Impact Assessment (EIA). Humber Eel Management Plan - Any improvements to habitats and water quality, and the naturalness of the river system are likely to contribute positively to the Eel Management Plan. There is a potential constraint for the River Hull FRM Strategy to hinder Eel management plan if migration of eel is in any way inhibited. The provision of eel passes at sluices and obstructions and screens at pumping stations will need to be considered either as stand- alone measures or when implementing the River Hull FRM Strategy. Pulfin Bog Water Level Management Plan (WLMP) - opportunities could be sought to improve the SSSI by contributing to the WLMP. However, at present we have also identified the potential for negative effects, directly or indirectly, on the Pulfin Bog SSSI for a number of the Strategy elements being considered. At the Strategy level, we cannot be sure what change may result, therefore, we have had to assume a worst case, which is that long-term increased flooding of the SSSI has the potential to have a negative effect on the habitat types present. Further detailed work is needed by ourselves, with Natural England, to consider this and we will be actively pursuing alternative partnerships and funding sources for actions that could minimise the impacts. Hull Headwaters SSSI WLMP - An objective of the River Hull FRM Strategy is to avoid damage to SSSIs, and so there should be no conflict with the Headwaters WLMP. Some River Hull FRM Strategy elements may also contribute, to some degree, to the objectives of the WLMP. In order to make an informed decision on whether certain Strategy elements could be implemented in the future, we would need to consider potential impacts on the River Hull Headwaters SSSI in more detail, as well as having more certainty on the role of other organisations and alternative funding River Hull Flood Risk Management Strategy Report 23

38 sources. This could be achieved by linkages to the actions identified in the River Hull Headwaters Restoration Plan. River Hull Headwaters Restoration project - Some River Hull FRM Strategy elements may also contribute, to some degree, to the objectives of the Restoration Plan. River Hull Flood Risk Management Strategy Report 24

39 3. Flood risk This section highlights the flood risk within the study area. It includes: definitions of flood risk and probability; a brief explanation of the causes of flooding in the River Hull catchment; a summary of the history of flooding; an overview of current flood risk management practices; a summary of the Summer 2007 flood and the work we have carried out since then; assessment of the current extent and frequency of flooding, and the level of flood risk; the likely changes to flood risk in the future, including climate change and change in land use. 3.1 Definitions Flooding and risk We frequently refer to flood risk and the probability of flood events, but what do we mean by these terms? As with all risk analyses, there are two elements that need to be considered, namely probability and consequence. 1. What is the probability that a flood event with a specified water level will occur? 2. What are the consequences of the flooding and what damage will result? When considering flood risk, and how best to manage it, we need to examine both of these elements. Flooding and probability Historically, the likelihood of a flood event was described in terms of its return period. For example, a 1 in 100-year event could be expected to be equalled, on average, once every 100 years. However, there is a tendency for this definition to be misunderstood. There is a perception that if a 1 in 100- year flood occurs; a repeat of the event will not be experienced for another 100 years. This is not the case; the key words in this example are on average. To try to avoid this misunderstanding, we now express flood events as the chance of them occurring in any one year at a given location. This can be stated in two ways, either as a chance or as a probability. Taking the above example, we would say that this event has a 1 in 100 chance or a 1% probability of being equalled in any year. We refer to this as the 1 in 100 (1%) annual exceedence probability (AEP) flood. 3.2 Causes of flooding This section explains the causes of flooding and illustrates where these flooding processes occur within the study area. Flooding processes When rain falls on land, it may either seep into the soil or run-off the surface. Generally speaking, when it flows over the surface or through the ground, it will eventually reach a drainage system, such as a ditch, stream or drain. These usually flow into larger drains or rivers downstream. If the quantity of water running off the land is greater than the capacity of the drainage system, flooding will occur. On a catchment scale, flooding of this nature from streams and rivers is known as fluvial flooding. It may affect widespread areas for periods of days or weeks. Generally the duration of flooding is shorter on small, steep tributary catchments and longer on larger, flatter rivers like the Hull and in places where floodwater River Hull Flood Risk Management Strategy Report 25

40 ponds on areas of floodplain. At the other end of the scale, localised flooding from drains and sewers can occur in built-up areas or on roads. This type of flooding is known as urban drainage flooding and is often caused by short, very heavy rain storms where flooding usually lasts for a matter of hours. Sometimes these processes interact. Drains or sewers may be unable to discharge due to high water levels in the watercourse at their downstream end. In some cases, direct run-off from steep rural hill slopes or from urban ground surfaces can cause flooding of roads or properties before it reaches a drainage system. This is called surface water flooding. Again it is often caused by short, very heavy rain storms and lasts for a few hours. However, sometimes it can be caused by prolonged periods of rainfall and can last for several days like in June Often the processes of urban drainage flooding and surface water flooding are difficult to distinguish Fluvial (river) flooding Some flooding occurs when high flows in the river cause water to overtop low spots in the flood defences. This mainly occurs in the upper reaches of the River Hull between Driffield and Hempholme Weir and on Frodingham Beck, Driffield Canal and Old Howe near Brigham and North Frodingham. A significant number of defences here overtop relatively frequently, every few years on average. The defences overtop to a lesser extent at several locations further downstream, these include Watton Beck, Catchwater Drain and Monk Dike. Flooding due to the River Hull overtopping as a result of tidal surges no longer occurs as the Hull Tidal Surge Barrier is closed when a tidal surge is forecast. Figure 3-1 Overtopping of River Hull at Wilfholme Much of the flooding in the Hull valley is caused by the low level drainage system not being able to discharge floodwaters quickly enough, causing the surrounding land to flood. This is mostly due to the flatness of the catchment and the influence of the tide at the downstream end. Although there are pumping stations that can pump water from Beverley and Barmston Drain into the River Hull, these are turned off when the River Hull water levels get too high during a flood. Flooding occurs along some parts of Beverley and Barmston Drain and Holderness Drain relatively frequently, every 2 to 5 years in places. River Hull Flood Risk Management Strategy Report 26

41 Figure 3-2 Flooding near Wilfholme caused by Beverley and Barmston Drain being unable to discharge Generally, the worst fluvial flooding in the catchment is caused by long duration floods that have a large total volume of rainfall and resulting runoff instead of short more intense storms; this is due to the watercourses and ground having little or no gradient. We are currently developing techniques to improve the flood forecasting and warning service for flooding from the main rivers and drains in the River Hull catchment Tidal flooding Tidal flooding in the River Hull catchment is primarily from the Humber Estuary. Flooding from the Humber can occur either because the tide level in the estuary rises above the level of the defences along the estuary shoreline (including those along the various dock frontages within the city of Hull), or because water from the estuary flows up the river and causes water levels to rise above the river defences. The River Hull Strategy does not address either form of tidal flooding because: A separate government approved Humber Strategy deals with the management of flood risk along the estuary shoreline and is now being implemented. The Hull Barrier is closed when a tidal event that could overtop the river defences is predicted, preventing any flow from the estuary causing flooding further upstream Groundwater flooding Another source of flooding in the study area is groundwater flooding. This has occurred in areas to the west of the River Hull along the edge of the Wolds where the water table in the chalk aquifer is close to the ground level and where natural springs can occur (Figure 3-3). Flooding usually takes place a few days or weeks after the rainfall has occurred as it takes time for the rainwater to percolate through to the chalk and the water table to rise. As the water drains out so the water table will fall again and the flooding will stop, although this can take several weeks to happen. Areas at risk include Cottingham, Dunswell and south of Driffield. River Hull Flood Risk Management Strategy Report 27

42 Figure 3-3 Location of natural springs Surface water flooding Surface water run-off has led to flooding in towns and villages, particularly where they are located close to the Wolds to the west of the River Hull. In these areas, surface water can flow down from the Wolds and through and into the more built-up areas below. Surface water flooding has occurred in Cottingham, Willerby, Beverley, Leconfield, Beeford and the Orchard Park and Derringham areas of Kingston-upon-Hull. Local surface water flooding occurs relatively frequently and generally causes only minor disruption and little if any damage to property. Extreme and large scale surface water flooding, such as that which occurred in June 2007, can cause widespread property damage. This scale of flooding is much more unusual and is estimated to only occur once every 100 to 200 years, on average. Flooding of main road routes from surface water flooding can cause major traffic disruption and make access difficult for emergency services. River Hull Flood Risk Management Strategy Report 28

43 Although the River Hull Strategy does not address surface water flooding, we are currently working with Local Authorities and other partner organisations to identify how best to manage it in the future. Hull City Council have been funded by Defra to prepare a Surface Water Management Plan and future actions and we have been involved in its development to ensure that our work is complementary. In the East Riding of Yorkshire the local authority have set up a Flood Liaison Panel which we are part of, along with other partner organisations such as Yorkshire Water. The purpose of this group is to look at all flooding issues across the area and to ensure we are joined up in our approach to reducing this risk Figure 3-4 Surface water flooding in Hull 3.3 Flood history Agricultural land and urban areas have been flooded from the River Hull, Holderness Drain, the Beverley & Barmston Drain and their tributaries throughout recorded history as well as in recent years. Some of the recent significant flood events are listed in Table 3.1. Date of Event January 1953 Table 3.1 Recorded flood events in the River Hull catchment Details Weather and tidal conditions combined to produce an extreme storm surge that affected many parts of the east coast. This surge travelled up the Humber Estuary causing catastrophic flooding to coastal areas A tidal surge caused widespread flooding to areas adjacent to River Hull and Holderness Drain through the City of Hull. This event resulted in flood damage to 855 houses. November 2000 Flooding occurred due to a long duration rainfall event, following one of the wettest autumns on record with twice the expected monthly rainfall in September resulting in ground saturation. An average rainfall of 250mm fell across areas of Yorkshire between the 26 th October and 8 th November resulting in widespread and prolonged flooding. Flooding occurred on the River Hull when the raised high level system was full of water and could not drain fast enough into the Humber Estuary. When this happened, the pumps draining the low level system into the River Hull had to be turned down as the high level system was full. This meant that the low level system (Beverley and Barmston Drain, Holderness Drain etc.) filled up until the low lying areas along side these drains started to flood. The flood water was stationary and mostly of shallow depth but the duration of flooding was in excess of 10 days at some locations. River Hull Flood Risk Management Strategy Report 29

44 Date of Event June 2007 Details Flooding took place in Hull at Setting Dyke at Coronation Road and Western Drain at Astral Close. Flooding was experienced in the East Ridings area from the Beverley and Barmston Drain, the Holderness Drain, the River Hull and Burstwick Drain owing to water levels overtopping the embankments (particularly at low spots). The flooding seen during this period was the most recent fluvial event of a significant magnitude. During June 2007, the River Hull catchment area was affected by a period of heavy and sustained rainfall causing some of its worst ever flooding with 8,657 houses, 1,300 businesses being inundated and 600 roads affected. Over 70mm of rain fell in part of the Hull area on the 15 th June and over 100mm of rain fell in parts of the Hull area on the 25 th June. The intensity of the rainfall overwhelmed ditches, drains and sewers and the low lying nature of the catchment exacerbated the problem. River levels on the River Hull reached 0.4 metres higher than previously recorded which would have led to some localised flooding, however, the severity of the surface water flooding caused the majority of problems within the Hull catchment. The difference between the November 2000 floods and the June 2007 floods was that flooding in November 2000 was as a result of increased river levels and not surface water flooding. Prior to the floods in 2000 and 2007, the worst flooding has been associated with tidal flooding such as the east coast floods of 1953 and the 1969 Hull Flood which swamped 855 houses. Tidal flooding has since been prevented by the construction of the Hull Tidal Surge Barrier which was commissioned in April 1980 and is currently undergoing an extensive mechanical and electrical refurbishment. The flooding in the summer 2007 highlighted the threat of surface water and sewer flooding to Kingston-upon-Hull and the surrounding area. During this event Yorkshire experienced flooding in a total of 27,197 properties with 8,476 being from fluvial flooding and 18,472 estimated to have been from surface water flooding. Of these a total of 7,208 residential and 1,300 commercial properties were located in Hull and these were primarily affected by sewer flooding. 3.4 Flood management in the River Hull catchment Responsibilities for flood management Several organisations are responsible for the management of watercourses and flood defences. We have legal powers to carry out works on designated main rivers, which are predominantly the larger rivers, although an increasing number of the smaller watercourses have recently been enmained. Main rivers are shown on a main river map. Our local Environment Agency office has a copy of this. All other rivers are referred to as ordinary watercourses. At present, other organisations with responsibilities and powers to manage watercourses and associated structures are: Internal Drainage Boards (IDBs) have responsibility for ordinary watercourses identified as main drains, located in areas known as Internal Drainage Districts. The IDB within the River Hull study area is the Beverley and North Holderness IDB and Preston IDB. In addition to the Environment Agency s powers to carry out flood defence works, the Kingston-upon-Hull Act 1984 gives Hull City Council certain powers to serve notices on the owners of land adjoining the River Hull requiring them to carry out works to prevent the overflow of the River Hull. If the landowner does not carry out the works the Council has the power to do the works itself and recover its costs from the landowner Maintenance of ordinary watercourses, which are not located in an Internal Drainage District, falls under the permissive powers of local authorities. River Hull Flood Risk Management Strategy Report 30

45 Water companies, such as Yorkshire Water, have responsibility for public sewerage systems. They have a statutory duty to effectively sewer an area. Highway authorities have responsibility for highway drainage. These will normally be the County Councils or Unitary Local Authorities, but in some cases it is the Highways Agency. Highway authorities and the Highways Agency are also responsible for some structures such as bridges and culverts. Landowners have certain rights and responsibilities 4 in relation to a watercourse flowing through or adjacent to their properties. These riparian rights are based on common law and have been developed as a result of legal cases over many years. These rights are not absolute, and riverside landowners may, in any event, have to obtain consent from the Environment Agency, local authority, or another body for certain activities connected with the watercourse. The Pitt Report recommends that local authorities should lead on the management of surface water flooding and drainage at the local level with the support of all responsible organisations including the Environment Agency, water companies and internal drainage boards, the Highways Agency and British Waterways 5. The government reviewed these responsibilities and the Flood and Water Management Act 2010 was passed in April It is due to be commenced in October 2010, but in the interim, Defra are expecting the Environment Agency to undertake an overseeing role for all aspects of flood risk. Proposals were published by Defra in March for a more holistic approach to flood management. Defra has taken an integrated approach to drainage management in high-risk urban areas through Surface Water Management Plans. These cover flooding from fluvial, drainage, surface water and groundwater sources. This will enable the authorities responsible for different parts of the drainage system to work together to assess and manage flood risks, taking a longterm strategic approach Flood defences Figure 3-5 shows the extent of purpose-built, maintained flood defences in the study area. Details of these flood defences are given in Tables 3.2. Table 3.2 River Hull flood defence assets Asset Description Amount (km) or Main river channels River Hull Beverley & Barmston Drain Holderness Drain Others Capacity (m 3 /s) 50 km 23 km 23 km 136 km Flood banks/walls 7 River Hull Others 75 km 86 km Main pumping Hempholme 1.9 m 3 /s stations Wilfhome 8.5 m 3 /s Tickton 2.5 m 3 /s Great Culvert 12 m 3 /s East Hull 7.5 m 3 /s Outfall structures Hedon road outfall, 1 no Average spend per year ( 000) 180 (Kingston-upon- Hull and urban area); 180 (Kingston-upon- Hull to Hempholme Weir); 80 (Upstream of Hempholme Weir) For further information refer to our free leaflet Living on the Edge An updated guide to the rights and responsibilities of a riverside owner available from our General Enquiry Line on Cabinet Office (December 2007), The Pitt Review, Interim Report 6 Defra (March 2005), Making Space for Water. Taking forward a new Government strategy for flood and coastal erosion risk management in England. First Government response to the autumn 2004 Making Space for Water consultation exercise km of the River Hull and 8km of other rivers are maintained by third parties River Hull Flood Risk Management Strategy Report 31

46 Asset Description Amount (km) or Holderness Drain: Pointing doors Mickley Dike Watton Beck Scurf Dike High Flags outfall, Beverley and Barmston Drain: Pointing doors Capacity (m 3 /s) 2 no 2 no 1 no 2 no Average spend per year ( 000) Other assets Hull Tidal Surge Barrier 100 In general, the River Hull catchment system can be split into three main sections: The high level system, formed by the River Hull headwaters and the River Hull (the main river into which the headwaters flow). The river discharges to the Humber Estuary through the tidal surge barrier, except during high tides when the barrier is closed. The low level system, which is formed predominantly by the artificial agricultural drainage network, including the Beverley and Barmston Drain. Flows are transferred from the low level system to the high level system via Wilfholme, Waterside and Hempholme pumping stations. This regulates water levels in the drains, whilst also influencing flow in the River Hull itself. The drain discharges to the River Hull by gravity at High Flags. Holderness Drain is predominantly a low level carrier draining the catchment to the east of the River Hull, including Lambwath Stream, New Drain, Stream Dike and Monk Dike. Holderness Drain runs parallel to the River Hull from just north of Wilfholme to the Humber where it outfalls through pointing doors at Hedon Road. To increase flow and reduce water levels in the drain upstream of the city, the drain is pumped from upstream to downstream at Tickton and Great Culvert pumping stations. East Hull pumping station is operated to enable discharge to the estuary during high tides. River Hull Flood Risk Management Strategy Report 32

47 Figure 3-5 Flood defences in the study area It is the high level system where the channels have historically been embanked. They have developed as perched systems in which the channel bed often now sits above the surrounding land. Through the urban area of Kingston-upon-Hull, the River Hull is highly engineered with hard bank protection. This high level system has the majority of the catchment s formal flood defences. There are approximately 160km of formal flood defences in the Hull catchment. Along the reaches of the river in the East Riding of Yorkshire and in the northern parts of Kingston-upon-Hull, the flood defences largely comprise earth embankments ( soft defences). Through the city a variety of steel sheet piling, concrete/timber wharves, stone walls, buildings and other structures form the hard defences along the river. The maintenance that we carry out varies between different watercourses and stretches of watercourses within the River Hull Strategy study area. River Hull Flood Risk Management Strategy Report 33

48 We inspect pumping stations at least once a week and carry out various electrical and mechanical maintenance between once a month and once a year. We clear weed screens as necessary. We regularly inspect flood defence embankments, which includes an annual inspection for vermin damage. Routine works on rivers and drains includes grass cutting, aquatic weed control/spraying and clearing debris out of urban watercourses. In addition we cut back vegetation between mid October and mid March. We remove any obstructions such as cars, fallen trees and any rubbish that may have been dumped. We also repair embankments and channel slips when needed Flood warning and forecasting We issue flood warnings to give residents and businesses that are at risk time to take action and help minimise the impacts of flooding on their property. There are four levels of flood warning, which are given below, together with their meanings: Flooding of low lying land and roads is expected. Be aware! Be prepared! Watch out! Flooding of homes and businesses is expected. Act now! Severe flooding is expected. There is extreme danger to life and property. Act now! Previous flood watches or warnings are no longer in force for the area. We issue flood warnings by a variety of means, including: Local media - We make extensive use of local media, including radio and television, to disseminate flood warnings. Floodline - Residents and businesses concerned about flood risk may telephone Floodline ( ) to obtain current flood warning information and general advice. A quick-dial number is available for each flood warning area, to allow callers to quickly access relevant information. Internet All flood warnings are noted on our website ( Floodline Warnings Direct (FWD) - This is the UK s first integrated multi-channel warning system and provides flood warnings and information to the public, professional partners and media across England and Wales. In addition to phone and fax messages which the AVM provided, FWD can now warn via SMS text messages and . Residents and businesses need to be registered with us to receive FWD; this can be done by contacting Floodline on At the moment we provide flood warnings to several communities along the River Hull, Beverley and Barmston Drain and Holderness Drain. The flood warning areas and associated trigger levels are currently under review. We have prepared local flood warning plans for Hull City Council and East Riding of Yorkshire Council. These provide local authorities and emergency services with information about flood risk and flood warning operations in their area. Hull City Council has prepared a Major Incident Plan for Kingston -upon-hull. This describes the actions to take during a major flood Development control and flood mapping Through encouraging appropriate development, we use development control principally to minimise increases in future flood risk, rather than to tackle existing flood risk. Section 2.4 notes some of the links between planning, development and flood risk. Although we currently have no River Hull Flood Risk Management Strategy Report 34

49 wider legal powers to control development in floodplains, we are consulted on planning applications as statutory consultees on any development in Flood Zone 3 and 2 (high and medium risk) and any development in Flood Zone 1 (low risk) over 1 hectare. A Flood Risk Assessment has to be submitted with all the applications and part of this is restricting the amount of surface water run-off from the development site. All new developments where we are consulted have to restrict the amount of surface water run-off as the existing drainage systems are at capacity, as you stated. Usually this can be done by using sustainable drainage techniques such as a balancing pond or underground storage tanks. This means that for any new developments where we are consulted there will be no extra pressure on the existing drainage infrastructure. For future land allocations we would ask the Local Planning Authority to look at the Flood Zones and to favour low risk areas as opposed to the high risk. We have also mapped Areas Susceptible to Surface Water Flooding. These are to be used by the LPA's when they are looking at sites for development allocations. We work with the planners on their allocations and policies in their Local Development Framework to ensure that future development does not add to the existing problem. We provide information on flood risk in the form of the Flood Map and the Flood Zones which are produced on a national scale by a flood mapping model. We provide them directly to local authorities for their planning work, and to individuals via our website. The Flood Zones show areas at risk from: i) A 1% AEP river flood event or 0.5% AEP tidal flood event (Flood Zone 3) ii) An extreme 0.1% AEP river or tidal flood (Flood Zone 2). iii) Land outside of the 0.1% AEP river or tidal flood (Flood Zone 1) The Flood Map is available on our website and provides additional information to the Flood Zones. The Flood Map classifies the likelihood of flooding into three categories (low, moderate or significant) taking flood defences into account, and it shows which areas benefit from flood defences. We update the national data based on more detailed local knowledge. The Flood Zones for the River Hull in the study area has been updated based on the detailed modelling and mapping work carried out for this Strategy (see section 3.5). 3.5 Assessment of current flood risk We have developed a computer-based hydraulic model of the River Hull system, which includes the main rivers, drains and floodplains in the Hull and Holderness Drain systems as well as numerous structures (including the pumping stations) and some smaller drains and culverts to be able to model the movement of the water around the catchment. Data used in the hydraulic model includes river cross-section surveys, ground levels of all the floodplain areas, and embankment levels from high resolution surveys. We have also completed a detailed hydrological analysis of the catchment to calculate the flood flows and volumes of water entering the rivers and drains at various locations during different magnitude floods; these flows are then input into the hydraulic model. Some of the flows include a component to represent groundwater flow in the river. The model has been developed and tested by simulating flood levels recorded in several real past flood events, including summer We have also spent a significant amount of time working with people who live and work in the area to test that our model accurately reflects what happens on the ground. The model has then enabled us to: Estimate flood levels for a range of events from the 1 in 2 (50%) AEP event to the 1 in 200 (0.5%) AEP event. Investigate possible future flood risk due to climate change. Test the effectiveness of possible flood risk management measures. River Hull Flood Risk Management Strategy Report 35

50 We have overlaid the model s predicted flood levels onto a ground elevation map of the River Hull catchment, to show the extent of land at risk from flooding. Figure 3-6 shows the predicted extent of flooding for a 1 in 2 (50%) AEP fluvial flood event and the 1 in 200 (0.5%) AEP fluvial flood event, for present day water levels taking into account the effect of the defences. More detail on the hydrology and hydraulic model are included in the Options Appraisal Report. Onset of flooding and standard of protection It is important to understand the likelihood of flooding occurring in our communities. For example, is there a 1 in 10 (10%) chance or a 1 in 100 (1%) chance of flooding occurring in any given year? When averaged over the long term, this corresponds to the frequency of disruption and flood damage likely to be experienced by a community. We have used the modelled flood levels to estimate the frequency with which the flood defences and the banks of the main drains would be overtopped by flooding. We call this frequency the onset of flooding. In some locations in the catchment, flood water can overtop a defence and then flow behind the defence parallel to the river causing flooding adjacent to higher defences that are not overtopped. Also, in some locations flooding can be caused by overtopping from more than one river or drain. For this reason we have used flood extents in combination with the onset of flooding of each watercourse to assess the flood risk to different parts of the catchment. The onset of flooding is not the same as the term standard of protection often used for a purpose-built flood defence, which refers to the event that the defence is designed to protect against. The height of designed defences includes an allowance for uncertainties in the estimated peak flood level, known as a freeboard allowance. This means that the standard of protection reported for a flood defence is usually lower than the onset of flooding due to overtopping. River Hull Flood Risk Management Strategy Report 36

51 Figure 3-6 Predicted extent of flooding (present day) River Hull Flood Risk Management Strategy Report 37