Guidance Booklet to the Management of Flooding & Flood Risk

Transcription

1 3 rd EDITION OXFORD AREA FLOOD INFORMATION Guidance Booklet to the Management of Flooding & Flood Risk 1

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3 OXFORD AREA FLOOD INFORMATION Contents Section Page 1 INTRODUCTION 5 2 PARTNERING ORGANISATIONS 7 3 FLOOD RESPONSE INFORMATION - Contact Details for Partners 9 - Flooding Information 12 - Response to Flood Warning & Flooding 20 - Health Risks 28 4 ALLEVIATING THE CAUSES OF FLOODING - Definitions of Watercourses & Drainage Systems 30 - Powers and Responsibilities for Maintenance 33 - Maintenance Priorities 35 5 OTHER SOURCES OF INFORMATION 48 3

4 This document has been produced by the Oxford Area Flood Group. Organisation representatives sitting on the Group were: John Hill (Chair) Richard Gosling Steve Smith Gathorne Gough Peter Dela John Kelly Gordon Hunt Katharine Dolman Roger Penny Graham Long Oxford City Council Oxford City Council Oxford City Council Vale of White Horse District Council Vale of White Horse District Council Oxfordshire County Council Oxfordshire County Council Environment Agency Thames Water Utilities Ltd Network Rail The Oxford Area Flood Group aims to annually review this document. The current representatives sitting on the Group are: Richard Gosling Oxford City Council Town Hall, Blue Boar St, Oxford, OX1 4EY. Steve Smith Oxford City Council Ramsay House, 10 St Ebbe s St, Oxford, OX1 1PT. Andrew Burchett Oxford City Council Marsh Road, Oxford, OX4 2HH. Gathorne Gough Vale of White Horse DC Abbey House, Abbey Close, Abingdon, Oxon, OX14 3JE. Peter Dela Vale of White Horse DC Abbey House, Abbey Close, Abingdon, Oxon, OX14 3JE. Anthony Concannon Oxfordshire County Council Emergency Planning Unit, Woodeaton Manor, Oxford, OX3 9GU. Gordon Hunt Oxfordshire County Council Speedwell House, Speedwell St, Oxford, OX1 1NE. Katharine Dolman Environment Agency Red Kite House, Howbery Park, Wallingford, Oxon, OX10 8DB. Nigel Bray Environment Agency Red Kite House, Howbery Park, Wallingford, Oxon, OX10 8DB. Jenny Elliott Thames Water Utilities Ltd Sewage Works, Sandford-on-Thames, Oxford, OX4 4XU. Roger Penny Thames Water Utilities Ltd Sewage Works, Sandford-on-Thames, Oxford, OX4 4XU. Graham Long Network Rail Network Rail Didcot Depot, 18 Basil Hill Road, Didcot, Oxon, OX11 7HJ. 4

5 Section One 1. INTRODUCTION 1.1. The current decade has seen the worst floods in the Thames Valley since In July 2007 the Environment Agency issued a severe flood warning for Oxford. Large areas in South and West Oxford, together with areas in Wolvercote and the neighbouring villages of Kennington and South Hinksey, were severely affected for several days. There was considerable disruption to transport services and businesses and a number of properties had to be evacuated This FLOOD INFORMATION has been drawn up in partnership with the Environment Agency, Oxfordshire County Council, Oxford City Council, Vale of White Horse District Council, Thames Water Utilities Ltd and Network Rail. It aims to provide residents in and around Oxford with information about the roles and responsibilities of the partners for: Maintaining the complex network of rivers, brooks, culverts, sewers and drains, which are relied upon for removing rainwater from the areas in which we live and work. And what can be expected from the partners in a flooding emergency This information is provided in four sections: AN INTRODUCTION to the PARTNER ORGANISATIONS RESPONDING TO FLOOD EMERGENCIES ALLEVIATING THE CAUSES OF FLOODING OTHER SOURCES OF INFORMATION 1.4. The RESPONSE TO FLOODING EMERGENCIES section gives details of how residents can help themselves and how the partners come together to manage flooding emergencies. Flooding is not confined to the City Council s administrative boundaries. Agencies in the Oxford area have detailed emergency plans for all major incident types including flooding The section ALLEVIATING THE CAUSES OF FLOODING gives information about responsibilities for maintaining land drainage and flood defences in the geographical area of Oxford City, and the neighbouring parishes of North Hinksey, South Hinksey and Kennington in the Vale of White Horse District. A complex network of rivers, streams, culverts, highway drains, public surface water sewers and private drains drain the area. Responsibility for this network is shared between several 5

6 organisations, which have jointly drawn up this document for public information The South and West quarters of Oxford, Port Meadow, Lower Wolvercote and neighbouring Kennington, Old Botley and South Hinksey are located within the River Thames floodplain. Part of Oxford and neighbouring Kidlington are located within the Cherwell floodplain. The floodplain is a terrace of rich meadows that first attracted early settlers to build permanent dwellings in the area. It has been formed by a natural cycle of seasonal flooding, which began at the end of the Ice Age and continues today. As Oxford has expanded, development has encroached into areas of the floodplain. It is therefore natural that rivers should endeavour to reclaim these areas in times of exceptionally high rainfall Flood defence measures have been installed by previous generations of inhabitants to limit the harm flooding can cause to property and economic activity in the area. However, continued pressure to provide more homes and expected changes in the weather patterns will require further measures if serious flooding is not to become more frequent around the Oxford area Flooding will remain a risk that cannot be entirely eliminated. The planned maintenance of flood defences aims to reduce the risk of and mitigate the effects of flooding, by making the most of the existing natural and man-made drainage infrastructure The Land Drainage Acts 1991 & 1994 is the principal statutory legislation that defines the role of the Environment Agency, and local councils in managing land drainage in England and Wales Figure 1 shows the geographical area that this document covers. The map shows the River Thames, the River Cherwell and other Main River watercourses supervised by the Environment Agency. It also shows the extent of the indicative 1-in-100 and 1-in-1000 year flood zones. There are many watercourses not shown on the map. The District Council supervises these. 6

7 2. PARTNERING ORGANISATIONS 2.1. Environment Agency: Section Two The Environment Agency is responsible for protecting and improving the environment in England and Wales. One aspect of the Environment Agency s work is reducing risks to people and to the developed and natural environment from flooding through: Flood forecasting, flood warning and response. Discouraging inappropriate development in areas at risk of flooding. Managing flood risk. The Thames in Oxford is administered from the regional offices in Reading and the area office in Wallingford Oxfordshire County Council: Oxfordshire County Council is the Highway Authority for the districts of Oxford City, Vale of White Horse, South Oxfordshire, Cherwell and West Oxfordshire. The County has a statutory duty to maintain roads, bridleways and footpaths within its area registered as Highway Maintainable at Public Expense. The County Council does not have a responsibility for trunk roads or motorways in the County. These are the responsibility of the Department for Transport and its agent the Highways Agency Oxford City Council: Oxford City Council is the principal second tier Operating Authority in the Oxford District. The City does not have a statutory duty to maintain watercourses, but it can use certain provisions in the Land Drainage Acts to secure the proper function of minor watercourses in its area Vale of White Horse District Council: The Vale of White Horse District Council is the principal second tier Operating Authority in the Kennington, Botley, North and South Hinksey areas of Oxfordshire covered by this plan. The Vale does not have a statutory duty to maintain watercourses, but it can use certain provisions in the Land Drainage Acts to secure the proper function of Ordinary Watercourses in its area. 7

8 2.5. Thames Water Utilities: Thames Water Utilities Ltd is a regulated utility company, which is owned by Kemble Water Limited. Kemble Water is a consortium led by Macquarie s European Infrastructure Funds, which is Australia s largest securities firm. The Secretary of State has appointed Thames Water Utilities as the statutory sewerage and water undertaker in the Thames Valley region. It is the largest UK water and wastewater company and is responsible for operating 31,000km of water mains and 66,000km of sewers in the Thames region Network Rail: Network Rail is a not-for-dividend company that is responsible for maintaining the entire railway infrastructure nationwide. The Thames Valley area office, which is part of the Western Territory of Network Rail, maintains the track in the Oxford area. The area office is located in Reading with a local depot at Didcot. Local bridges and other structures belonging to Network Rail are managed from the territory HQ in Swindon British Waterways: British Waterways is a public corporation that cares for over 3,000km of inland waterways in the UK. The Oxford Canal is managed from its South East Division Office in Milton Keynes. 8

9 FLOOD RESPONSE INFORMATION Contact details for each agency and other useful information Agency Daytime contact number Out of hours Thames Water Environment Agency Environment Agency Floodline Quickdial numbers Thames = Cherwell = Quickdial numbers Thames = Cherwell = Oxford City Council Oxford City Council City Works Engineering Services Cowley Marsh Depot Flooding office hours (Oxford City area) Flooding after hours (Oxford City area) Oxford City Council Via Control Centre Environmental Health on Oxfordshire County Highways Vale of White Horse District Council West Oxfordshire District Council South Oxfordshire District Council Cherwell District Council Scottish and Southern Electric Transco Gas Emergencies Meteorological Office British Waterways Network Rail Thames Valley Police Oxfordshire Fire & Rescue Local Media BBC Oxford 95.2FM Tele: Fox FM 102.6FM Tele:

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11 Section Three FLOOD RESPONSE INFORMATION 3.1 INTRODUCTION a) What this section does This section provides general advice about flooding and what you can do to help protect your property. It also provides information on the role of each agency that helps with flooding and how they might respond. b) Personal and public agency responsibility Whilst public agencies have a major role in the event of flooding, it is important to remember they cannot do everything. Individual householders and owners of land adjacent to certain watercourses have a responsibility too. Riparian owners and occupiers have particular responsibilities in respect of watercourses, and these are set out in the Environment Agency's publication Living on the Edge available from the Environment Agency national customer contact centre on , and website ( Owners of properties at risk of flooding have a responsibility to help themselves and protect their homes from flooding (Section 5 will help you to find sources of information about protecting your property). 11

12 3.2 FLOODING INFORMATION a) Weather warnings The Meteorological Office issues severe weather warnings that are distributed to the emergency services and local councils in the Oxford area. These include forecasts of very heavy rain or snow, which could lead to flash flooding of roads and watercourses. Under the National Severe Weather Warning System, advice of severe weather is provided to many agencies. These warnings will also be passed on to the public through national and local weather forecasts on TV, local radio, and Ceefax, which will mention potential flooding. The Meteorological Office also issue flash and early severe weather warnings via their website ( Early Warnings of Severe or Extreme Weather These are issued when the Met Office has 60% or greater confidence that severe weather is expected in the next few days. Flash Warning of Severe or Extreme Weather These are issued when the Met Office has 80% or greater confidence that severe weather is expected in the next few hours. Advisory Warning of Severe or Extreme Weather These advisories are issued by 1100 daily as routine and indicate confidence of expected severe or extreme weather. Early warnings and Flash Warnings supersede advisories when confidence levels are 60% or greater. b) Types of flooding The types of flooding that could occur in the Oxford area are: Fluvial Flooding Main River channels are unable to cope with the volume of water entering the river system. The river waters over-top the channel banks and the excess water is stored in the floodplain. Low-lying properties within the floodplain are at risk of flooding. As flooding gets worse floodwater will extend from the floodplain into other areas. Flash Flooding Road gullies and local watercourses are unable to cope with a downpour. Water collects in lower spots and local watercourses can be overwhelmed leading to floodwater flowing temporarily over ground. Properties adjacent to any water flowing over the ground are at risk of inundation. Groundwater There are no major aquifers in the Oxford area. However, there are isolated areas of an ancient gravel terrace in West and South Oxford, which are water bearing. The groundwater levels in the gravels do rise and fall as water levels in adjacent rivers change. Properties with cellars or suspended floors built on the gravels are vulnerable to groundwater leaking into them. Owners are strongly advised to obtain professional advice before considering any change of use of these areas. 12

13 Sewerage There are two separate sewerage systems in the Oxford area. One collects and disposes of rainwater to the nearest watercourse. A separate system collects wastewater from within dwellings and delivers it to the Sandford Sewage works for treatment and disposal. Thames Water Utilities Ltd manages both systems. The waste water system also relies on a number of pumping stations, which have means of automatically warning in the event of a breakdown. The pipe-work that carries the wastewater to the local pumping station may become blocked, which in some circumstances can lead to over-ground flooding. Properties with sanitary fittings in the cellar are more at risk of internal flooding. Owners are strongly advised to obtain professional advice before considering any change of use, particularly if it is to be made into habitable space. Water Mains Fresh water is delivered to every dwelling in the City and surrounding district by a local network of pipes buried in the ground, typically about 90cm deep. Most of the pipes are relatively small in diameter. There are a number of breakages each year, the majority being the result of contractors excavating close to the pipes. While these breakages can cause disruption to the water supply, they rarely cause serious flooding. However, the local network is fed by a small number of large water mains that, if fractured, can cause serious flooding. c) Preparing for flooding To see if your home, business or land is near to a potential source of flooding, use the Environment Agency s What s in your backyard? web page at Wherever you live the following information will help you take steps to reduce risks and increase your protection from flooding. If you live in an area where there can be a high risk of flooding, whilst the emergency services and local authorities will do everything possible to help, it is your responsibility to look after your property. You might find the following advice helpful in case of flooding: Make a family flood plan Flooding often happens quickly and when you least expect it. Making a flood plan is an excellent way of preparing you and your family should a serious flood take place. When devising your flood plan, be sure to involve everyone in your home including your children. Make sure everyone knows what will happen should you need to put your flood plan into action. Practising it beforehand is one way for you to make sure everyone is prepared. A list of useful numbers Make sure you have a list of all the useful phone numbers that you need: for example your local council, the emergency services, your insurance company, the Environment Agency s Floodline number ( ) and the quickdial code relevant for your location (see page 9). 13

14 Useful contacts can also be found in the Oxfordshire Flood Directory, which can be ordered by calling the Environment Agency on Put together your own flood kit The first step in protecting and helping yourself before flooding is to make sure you have made your own flood kit and that everyone in your house knows where to find it. These can be made up from common items around the home such as: Important personal documents A torch and spare batteries A battery-powered or wind-up radio Rubber gloves A first-aid kit Baby essentials Pet essentials Important phone numbers A disposable camera Wellington boots Waterproof clothing Mobile phone and charger Blankets Toiletries Thermos. Children s essentials Make a list of the vital items you will need. For example, milk, baby food, sterilised bottles and spoons, nappies and wipes, nappy bags, spare clothing, comforter, favourite toy or best teddy. Medication Would you need to take any family medication? Valuable and sentimental belongings Get into the habit of storing them upstairs or in a high place downstairs. Flood boards and sandbags Have a few flood boards or sandbags prepared to block doorways and airbricks. There are more details about flood protection later in this document. Gas and electricity Do you know where and how to turn off supplies, even in the dark? Car Where would you move it to and at what point? 14

15 Evacuation If the flooding is severe, you may be evacuated. What would you need to take with you and what provision can you make for family pets? If you choose to leave the house (without being evacuated) do you know where you would go and how would you get there? If you decide to stay in the house but decamp upstairs, make a list of all the things you will need. Advice and guides There is a range of fact sheets, advice and guides available from the partner organisations. These are designed to help you prepare for flooding and a list can be found in Section 5. The Environment Agency has produced a comprehensive range of guides and flooding advice and information. These are listed in Section 5 but further information that is frequently updated can be found on the website at d) Flood protection products A range of products is available to help reduce or prevent flooding of homes and businesses. Barriers, boards and covers are more suited to areas where there is a history of flooding, usually each year. The Environment Agency is supporting the Kite Mark scheme, which ensures that flood protection products are fit for their purpose. A number of products bearing the Kite Mark are already on the market and these are listed on the Environment Agency website at The National Flood Forum publicises regular Flood Fairs where visitors can seek expert advice, talk to retailers and buy flood protection products. The National Flood Forum lists non-kite-marked flood protection products on its website at Retailers are represented by a trade organisation, the Flood Protection Association. e) In the event of flooding If flooding occurs you might find the following advice helpful: 1. Take all practical steps to prevent water from entering your property 2. Do your best to put moveable belongings at a higher level 3. Be prepared to move upstairs or to leave your home. Pack a suitcase with spare clothing, wash kit, valuables and medicines 4. If you decide to leave, turn off electricity and gas at the mains 5. Make certain that you have home contents insurance (and building insurance if you are a house owner) and take the policy details with you 15

16 6. Lock your house before leaving and tell the police as soon as possible that you have moved out for the foreseeable future (t: ) Remember floodwater is dangerous take care of children and pets When appropriate, flood warnings and advice will be broadcast on local radio so stay tuned! f) Flood Warnings and what they mean The Environment Agency s Local Flood Warning Plan for Oxfordshire provides details of the Flood Warning arrangements for Oxfordshire. The River Thames and the River Cherwell are the two largest rivers in the area covered by this plan where there is a risk of flooding. The Environment Agency is responsible for issuing Flood Warnings to the public, businesses, local authorities, utilities and the emergency services and the media. There are four warning codes, which can be issued in any order. These are: 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! Flood Watches and Flood Warnings are no longer in force in this area. Flood Watch is issued for areas of the floodplain within a catchment or group of catchments at risk from minor impact flooding from Main Rivers and Ordinary Watercourses. It is generally only issued to those people closest to the river or rural landowners, local authorities and emergency services. When a Flood Watch is issued people may consider taking the following action where they can: Ring Floodline on for up-to-date flooding information Tune in to weather and travel bulletins (Radio Oxford on 95.2FM or Fox FM on 102.6FM) Keep a watch on the weather and water levels Tell your family, friends and neighbours 16

17 Drive carefully roads may be flooded Check livestock and keep pets safe Check availability of torches and batteries Be prepared be aware watch out! Check where to turn off your gas and electricity supply. Flood Warning and Severe Flood Warning relate to specific Flood Warning areas at risk of flooding from rivers. Oxford falls within two Flood Warning areas. They are: Lower Heyford to Oxford on the River Cherwell and Eynsham Lock to Sandford Lock on the River Thames. Flood Warnings are issued when the Environment Agency is expecting property to flood. When a Flood Warning is issued people may consider taking the following action where they can: Ring Floodline on for up-to-date flooding information Stay tuned to radio (Radio Oxford on 95.2FM or Fox FM on 102.6FM) and television weather, news and travel bulletins Move family, pets and valuables to safety Farmers move livestock to higher ground Help neighbours Use sandbags or flood boards to block doors and airbricks Don t drive through floodwater Be prepared to turn off gas and electricity supply. Severe Flood Warnings are issued when extreme danger to life and property within a Flood Warning area is anticipated. When a Severe Flood Warning is issued people may consider taking the following action where they can: Protect yourself, your family, pets and valuables floods can kill Co-operate with emergency services and the authorities people may be evacuated from their homes to emergency centres Ring Floodline on for up-to-date flooding information Stay tuned to radio (Radio Oxford on 95.2FM or Fox FM on 102.6FM) and television weather, news and travel bulletins Turn off power supplies and be ready for power cuts and loss of services including water supply 17

18 Avoid contact with floodwater it may be contaminated. All Clears are issued when floodwaters have subsided and there is no longer considered to be a risk of flooding. When an All Clear is issued people may consider keeping an eye on the weather and water levels in case the situation deteriorates and new Flood Watches or Flood Warnings are issued. Flood Warnings are issued via the Environment Agency s Flood Warning System; Floodline Warnings Direct, and also displayed on their website: Floodline Warning Direct is a multi media messaging system used by the Environment Agency to provide a free Flood Warning service to people who have registered with the Agency to receive this service. If you live in or have a business in an area that could flood, you are strongly advised to register for this free service. Telephone: g) Sandbags Whilst local authorities have no statutory obligation to provide material for flood protection, some, as far as their resources will allow, will supply sandbags as an emergency measure. Telephone your District Council for the latest information about availability of sandbags and where they can be collected from. You will find their number on the contact details sheet. The current policy of each local authority is summarised below: 18

19 Local Authority Oxford City Council Vale of White Horse South Oxfordshire Cherwell District West Oxfordshire County Council Policy (see websites for further details) Will supply sandbags free of charge resources permitting. The Council will always try to provide assistance where it is considered most needed and if resources, circumstances and budgets permit. It has a limited supply of sandbags, which are used primarily for the protection of vulnerable homes when occupied homes are in imminent danger of flooding or have a history of flooding. We cannot provide sandbags for protecting gardens or outbuildings. The Council provides sandbags free of charge to residential properties that are in imminent danger of flooding. Sandbags are also available to commercial properties for a small charge ( 5 per bag). The primary responsibility for the protection of his/her property lies with the householder. The Council will keep stocks of filled sandbags with which to respond in cases of flooding emergencies. These stocks will be replenished as soon as practicable as they are used. The Council s powers in helping to relieve flooding and prevent flood damage are permissive. The Council will respond to calls for assistance as much as possible consistent with its resources at the time and the circumstances of the flooding. The Council will not promise to deliver sandbags but it will do so as far as resources and circumstances allow. The Council will deliver sandbags free of charge to private householders in times of emergency but may make a small charge to businesses. The Council will not collect used sandbags. Householders will be expected to dispose of these themselves. The Council has no legal responsibility to provide assistance to residents of the district during times of flood; however, the Council has provided emergency assistance on an ad hoc basis dependent upon local knowledge and experience of the situation. The Council will provide sandbags or other such equipment as it feels appropriate, if they are available, to assist with the defence from flooding to persons or property within the district. May provide back-up supplies, resources permitting. County Council will also co-ordinate the acquisition of further supplies from sources such as the Army, if these are available. 19

20 However, householders are advised not to rely on the Council being able to respond to all needs in an emergency and should consider measures that can be taken now to prepare for potential flooding in the future. Householders and businesses should make their own plans to handle a flood emergency, including providing their own sandbags. You can buy sandbags from builders' merchants. However, there is nothing special about sandbags. Other types of bag like growbags, bin liners or plastic bags filled with earth can also help to keep water out. The Environment Agency provides comprehensive information about how both to protect your property from flooding and what to do if you are affected (see information on publications in Section 5 or the Environment Agency s website at RESPONSE The response to a major flooding incident involves a number of organisations working together at a local level, namely the police, fire service, local authorities, Environment Agency and other bodies such as British Waterways, public utility companies, the communications media, voluntary organisations and the public. Outlined below are the broad roles and responsibilities of these organisations. In most cases the scale of flooding in the area will dictate the available resources. a) Emergency Response Most agencies have generic emergency plans to deal with the consequences of any major incident and most contain additional information on specific incidents such as flooding. These plans are regularly exercised and many of the agencies deal with emergencies on a day-to-day basis. These plans provide details of available resources and contacts to enable additional resources to be made available. These could include rest centres to accommodate evacuated residents, transport, sandbags, helplines etc. There is a nationally agreed Command and Control system for major incidents and the same principles would apply in the event of major flooding. The response is organised at three levels: Bronze the operational level Bronze is the level at which the management of immediate hands-on work is undertaken at the site(s) of the emergency. Personnel first on the scene will take immediate steps to assess the nature and extent of the problem. Bronze commanders will concentrate their effort on the specific tasks within their areas of responsibility for example, the police will concentrate on establishing cordons, maintaining security and managing traffic. In most instances, the police will co-ordinate the operational response at the scene to ensure a coherent and integrated multi-agency response. 20