Waltham Forest Council Level 2 Strategic Flood Risk Assessment

Total Page:16

File Type:pdf, Size:1020Kb

Waltham Forest Council Level 2 Strategic Flood Risk Assessment Waltham Forest Council Level 2 Strategic Flood Risk Assessment Final Report May 2011 Prepared for Waltham Forest Council Level 2 Strategic Flood Risk Assessment Revision Schedule Level 2 Strategic Flood Risk Assessment May 2011 Rev Date Details Prepared by Reviewed by Approved by 01 October 2010 Draft Report for Emily Blanco Elizabeth Gent Elizabeth Gent Client Comment Senior Flood Risk Specialist Principal Consultant Principal Consultant Tom Edwards Jon Robinson Senior Consultant Technical Director 02 December Final Report Tom Edwards Elizabeth Gent Jon Robinson 2010 incorporating Senior Consultant Principal Consultant Technical Director client and EA comments 03 March 2011 Final Report Tom Edwards Jon Robinson Jon Robinson incorporating Senior Consultant Technical Director Technical Director further comments 04 May 2011 Final Report Tom Edwards Jon Robinson Jon Robinson with minor Senior Consultant Technical Director Technical Director amendments This document has been prepared in accordance with the scope of Scott Scott Wilson Wilson's appointment with its client and is subject to the terms of that 6-8 Greencoat Place appointment. It is addressed to and for the sole and confidential use and reliance of Scott Wilson's client. Scott Wilson accepts no liability for any use of London this document (or any model included or referred to herein) other than by its SW1P 1PL client and only for the purposes for which it was prepared and provided. No person other than the client may copy (in whole or in part) use or rely on the contents of this document, without the prior written permission of the Company Tel +44 (0)20 7798 5000 Secretary of Scott Wilson Ltd. Any advice, opinions, or recommendations within Fax +44 (0)20 7798 5001 this document should be read and relied upon only in the context of the document as a whole. The contents of this document do not provide legal or tax advice or opinion. © Scott Wilson [Ltd] 2011 www.scottwilson.com Waltham Forest Council Level 2 Strategic Flood Risk Assessment Executive Summary Scott Wilson has been commissioned to prepare a Level 2 Strategic Flood Risk Assessment (SFRA) on behalf of Waltham Forest Council. This assessment builds on the findings of the North London Level 1 SFRA1 and provides more detailed information regarding fluvial flood risk associated with the River Lee system along the western margin of the borough. The purpose of this increased scope Level 2 SFRA is to enable the application of the PPS25 Exception Test and to contribute to the evidence base for Waltham Forest’s Local Development Documents (LDDs), with particular reference to the Area Action Plans (AAPs) for the Blackhorse Lane Area and Northern Olympic Fringe Area. This study has utilised available hydraulic modelling information to produce mapping outputs which define the flood extents and provide further detail regarding the likely depth of flooding and flood hazard classification during a range of flood events. The mapping outputs should be used to refine and update the PPS25 Sequential Test process. If, as anticipated, this confirms that some development is required within flood risk areas to provide wider sustainability benefits to Waltham Forest then the outputs can be used to inform the PPS25 Exception Test. The Flood Depth and Flood Hazard mapping should be used to apply a sequential planning approach, whereby the most vulnerable development types are located within the lowest flood risk areas. In order to ensure that future development proposed within flood risk areas is safe, and does not increase flood risk in adjacent areas, a number of development control measures will need to be enforced, such as, the location and layout of different type of development according to vulnerability; setting of appropriate finished floor levels; provision of safe access and egress; the use of appropriate flood resistant and resilient construction techniques in accordance with expected flood depths; provision of safe refuge above the flood level; and identification of suitable evacuation procedures in the event of a flood. Specific guidance and recommendations with respect to flood risk mitigation measures for future development are provided within this report which should be addressed as part of a site specific Flood Risk Assessment to support the planning application. Information on when a Flood Risk Assessment is required, the varying levels of Flood Risk Assessments, and the minimum requirements of an FRA have also been outlined. A walkover of the main flood defence network has been completed to provide an indication of the current standard of flood protection. This suggests that the standard of protection associated with parts of the Ching Brook and Dagenham Brook is less than 1 in 20 years. The River Lee Flood Relief Channel offers a slightly improved standard of protection, estimated as approximately 1 in 50 years however these standards highlight the actual risk of flooding which is present within Waltham Forest. Additional investment in flood defence infrastructure will be required in the future to prevent the standard of protection reducing further in the face of increasing urbanisation, climate change and an ageing defence network. It is recommended that the areas highlighted as having the lowest standard of protection should initially be targeted for future improvements, and detailed studies will be required develop potential options and evaluate impacts. It is considered unlikely that construction of new, large scale flood defence infrastructure provides a sustainable flood risk management approach for Waltham Forest, as such measures can often relocate flooding problems to adjacent areas. It is therefore recommended that the regeneration plans throughout 1 Mouchel (August 2008) North London Strategic Flood Risk Assessment D133184 May 2011 i Waltham Forest Council Level 2 Strategic Flood Risk Assessment the study area should be viewed as a mechanism through which reduction in the level of flood risk can be achieved. This will require incorporation of flood storage and other on site mitigation such as use of sustainable drainage techniques to provide attenuation and reduce surface water runoff. D133184 May 2011 ii Waltham Forest Council Level 2 Strategic Flood Risk Assessment Table of Contents Acronyms & Abbreviations .......................................................................................................................... v Glossary ........................................................................................................................................................ vi 1 Introduction .................................................................................................................................... 1 1.1 Background ...................................................................................................................................... 1 1.2 Aims & Objectives ............................................................................................................................ 1 1.3 Methodology ..................................................................................................................................... 2 1.4 Previous Flood Risk Studies ............................................................................................................ 2 2 Study Area Characteristics ........................................................................................................... 4 2.1 Overview .......................................................................................................................................... 4 2.2 Topography ...................................................................................................................................... 5 2.3 River Network ................................................................................................................................... 5 2.4 Reservoir Network ............................................................................................................................ 7 3 Flood Risk in Waltham Forest ...................................................................................................... 9 3.1 Fluvial Flooding ................................................................................................................................ 9 3.2 Surface Water Flooding ................................................................................................................. 15 3.3 Groundwater Flooding.................................................................................................................... 16 3.4 Sewer Flooding .............................................................................................................................. 17 3.5 Artificial Sources ............................................................................................................................ 18 4 Specific Area Considerations ..................................................................................................... 19 4.1 Overview ........................................................................................................................................ 19 4.2 Sequential Approach ...................................................................................................................... 19 4.3 Key Flooding Mechanism ............................................................................................................... 19 4.4 Blackhorse
Recommended publications
  • Middlesex University Research Repository an Open Access Repository Of
    Middlesex University Research Repository An open access repository of Middlesex University research http://eprints.mdx.ac.uk Read, Simon ORCID: https://orcid.org/0000-0002-2380-5130 (2017) Cinderella River: The evolving narrative of the River Lee. http://hydrocitizenship.com, London, pp. 1-163. [Book] Published version (with publisher’s formatting) This version is available at: https://eprints.mdx.ac.uk/23299/ Copyright: Middlesex University Research Repository makes the University’s research available electronically. Copyright and moral rights to this work are retained by the author and/or other copyright owners unless otherwise stated. The work is supplied on the understanding that any use for commercial gain is strictly forbidden. A copy may be downloaded for personal, non-commercial, research or study without prior permission and without charge. Works, including theses and research projects, may not be reproduced in any format or medium, or extensive quotations taken from them, or their content changed in any way, without first obtaining permission in writing from the copyright holder(s). They may not be sold or exploited commercially in any format or medium without the prior written permission of the copyright holder(s). Full bibliographic details must be given when referring to, or quoting from full items including the author’s name, the title of the work, publication details where relevant (place, publisher, date), pag- ination, and for theses or dissertations the awarding institution, the degree type awarded, and the date of the award. If you believe that any material held in the repository infringes copyright law, please contact the Repository Team at Middlesex University via the following email address: [email protected] The item will be removed from the repository while any claim is being investigated.
    [Show full text]
  • Thames River Basin Management Plan, Including Local Development Documents and Sustainable Community Strategies ( Local Authorities)
    River Basin Management Plan Thames River Basin District Contact us You can contact us in any of these ways: • email at [email protected] • phone on 08708 506506 • post to Environment Agency (Thames Region), Thames Regional Office, Kings Meadow House, Kings Meadow Road, Reading, Berkshire, RG1 8DQ The Environment Agency website holds the river basin management plans for England and Wales, and a range of other information about the environment, river basin management planning and the Water Framework Directive. www.environment-agency.gov.uk/wfd You can search maps for information related to this plan by using ‘What’s In Your Backyard’. http://www.environment-agency.gov.uk/maps. Published by: Environment Agency, Rio House, Waterside Drive, Aztec West, Almondsbury, Bristol, BS32 4UD tel: 08708 506506 email: [email protected] www.environment-agency.gov.uk © Environment Agency Some of the information used on the maps was created using information supplied by the Geological Survey and/or the Centre for Ecology and Hydrology and/or the UK Hydrographic Office All rights reserved. This document may be reproduced with prior permission of the Environment Agency. Environment Agency River Basin Management Plan, Thames River Basin District 2 December 2009 Contents This plan at a glance 5 1 About this plan 6 2 About the Thames River Basin District 8 3 Water bodies and how they are classified 11 4 The state of the water environment now 14 5 Actions to improve the water environment by 2015 19 6 The state of the water
    [Show full text]
  • LONDON METROPOLITAN ARCHIVES Page 1 BRITISH WATERWAYS BOARD
    LONDON METROPOLITAN ARCHIVES Page 1 BRITISH WATERWAYS BOARD ACC/2423 Reference Description Dates LEE CONSERVANCY BOARD ENGINEER'S OFFICE Engineers' reports and letter books LEE CONSERVANCY BOARD: ENGINEER'S REPORTS ACC/2423/001 Reports on navigation - signed copies 1881 Jan-1883 Lea navigation Dec 1 volume ACC/2423/002 Reports on navigation - signed copies 1884 Jan-1886 Lea navigation Dec 1 volume ACC/2423/003 Reports on navigation - signed copies 1887 Jan-1889 Lea navigation Dec 1 volume ACC/2423/004 Reports on navigation - signed copies 1890 Jan-1893 Lea navigation Dec 1 volume ACC/2423/005 Reports on navigation - signed copies 1894 Jan-1896 Lea navigation Dec 1 volume ACC/2423/006 Reports on navigation - signed copies 1897 Jan-1899 Lea navigation Dec 1 volume ACC/2423/007 Reports on navigation - signed copies 1903 Jan-1903 Lea navigation Dec 1 volume ACC/2423/008 Reports on navigation - signed copies 1904 Jan-1904 Lea navigation Dec 1 volume ACC/2423/009 Reports on navigation - signed copies 1905 Jan-1905 Lea navigation Dec 1 volume ACC/2423/010 Reports on navigation - signed copies 1906 Jan-1906 Lea navigation Dec 1 volume LONDON METROPOLITAN ARCHIVES Page 2 BRITISH WATERWAYS BOARD ACC/2423 Reference Description Dates ACC/2423/011 Reports on navigation - signed copies 1908 Jan-1908 Lea navigation/ stort navigation Dec 1 volume ACC/2423/012 Reports on navigation - signed copies 1912 Jan-1912 Lea navigation/ stort navigation Dec 1 volume ACC/2423/013 Reports on navigation - signed copies 1913 Jan-1913 Lea navigation/ stort navigation
    [Show full text]
  • Lee Valley Regional Park Strategic Planning Evidence and Policies
    Lee Valley Regional Park Authority Park Development Framework Strategic Policies April 2019 Lee Valley Regional Park Authority Park Development Framework Strategic Policies Prepared by LUC Planning & EIA LUC LONDON Offices also in: Land Use Consultants Ltd Design 43 Chalton Street Bristol Registered in England Registered number: 2549296 Landscape Planning London Edinburgh Registered Office: Landscape Management NW1 1JD Glasgow 43 Chalton Street Ecology T +44 (0)20 7383 5784 Lancaster London NW1 1JD GIS & Visualisation [email protected] Manchester FS 566056 EMS 566057 LUC uses 100% recycled paper Executive Summary Extending north from East India Dock Basin for 26 miles, and broadly aligned with the natural course of the river Lea through east London and Essex to Ware in Hertfordshire, the Lee Valley Regional Park presents a rich tapestry of award winning international sports venues, attractive parklands and areas of significant ecological importance. The Park attracts over 7 million visits each year largely drawn from London, Hertfordshire and Essex but given the international status of its venues increasingly from across the United Kingdom and abroad. The Regional Park lies at the centre of one of Europe’s largest regeneration areas which includes London 2012 and its Legacy, major developments in the lower Lee Valley, Meridian Water and a range of large schemes coming forward in Epping Forest District and the Borough of Broxbourne. The Authority’s adopted policies date from 2000 and, given the Regional Park’s rapidly changing context, a new approach is required. The Strategic Aims and Policies, Landscape Strategy and Area Proposals included in the Park Development Framework are designed to respond to this changing context to ensure that the Regional Park can maintain its role as an exciting and dynamic destination which caters for leisure, recreation and the natural environment over the next 10-15 years.
    [Show full text]
  • E Guide the Travel Guide with Its Own Website
    Londonwww.elondon.dk.com e guide the travel guide with its own website always up-to-date d what’s happening now London e guide In style • In the know • Online www.elondon.dk.com Produced by Blue Island Publishing Contributors Jonathan Cox, Michael Ellis, Andrew Humphreys, Lisa Ritchie Photographer Max Alexander Reproduced in Singapore by Colourscan Printed and bound in Singapore by Tien Wah Press First published in Great Britain in 2005 by Dorling Kindersley Limited 80 Strand, London WC2R 0RL Reprinted with revisions 2006 Copyright © 2005, 2006 Dorling Kindersley Limited, London A Penguin Company All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without the prior written permission of the copyright owner. A CIP catalogue record is available from the British Library. ISBN 1 4053 1401 X ISBN 978 1 40531 401 5 The information in this e>>guide is checked annually. This guide is supported by a dedicated website which provides the very latest information for visitors to London; please see pages 6–7 for the web address and password. Some information, however, is liable to change, and the publishers cannot accept responsibility for any consequences arising from the use of this book, nor for any material on third party websites, and cannot guarantee that any website address in this book will be a suitable source of travel information. We value the views and suggestions of our readers very highly. Please write to: Publisher, DK Eyewitness Travel Guides, Dorling Kindersley, 80 Strand, London WC2R 0RL, Great Britain.
    [Show full text]
  • Regional Flood Risk Assessment
    London Regional Flood Risk Appraisal First Review August 2014 Contents Page Updating the January 2014 Consultation Draft 3 Executive Summary 4 Chapter 1 - Introduction 1.1 Wider Policy Background 5 1.2 The London Plan 6 1.3 The Sequential Test 8 1.4 How to use this RFRA 9 Chapter 2 - Overview of Flood Risk to London 2.1 Tidal Flood Risk 10 2.2 Fluvial Flood Risk 15 2.3 Surface Water Flood Risk 23 2.4 Foul Sewer Flood Risk 27 2.5 Groundwater Flood Risk 28 2.6 Reservoir Flood Risk 29 Chapter 3 – Spatial Implications of Flood Risk 3.1 Introduction 32 3.2 Specific Development Areas 33 3.3 Main Rail Network and Stations 47 3.4 London Underground & DLR Network 48 3.5 Main Road Network and Airports 49 3.6 Emergency Services 51 3.7 Schools 52 3.8 Utilities 53 3.9 Other Sites 55 Chapter 4 – Conclusions and Look Ahead 56 Appendix 1 List of Monitoring Recommendations 57 Appendix 2 Glossary 59 Appendix 3 Utility Infrastructure within Flood Risk Zones 60 Appendix 4 Comparison of Flood Risk Data with 2009 RFRA 66 Appendix 5 Flood Risk Maps Separate Document London Regional Flood Risk Appraisal – First Review – August 2014 page 2 of 66 Updating the January 2014 Consultation Draft This document represents an update of the draft, that was published in January 2014, in the light of a three-month consultation. Alongside further assistance by the Environment Agency, this final version of the First Review was also informed by responses the Mayor received from TfL as well as the London Boroughs of Richmond, Havering and Southwark (see Statement of Consultation provided separately).
    [Show full text]
  • Appendix B: Baseline Data
    London Borough of Waltham Forest Submission Local Plan Part 1 Sustainability Appraisal Report Appendix B: Baseline Data Date: 28th April 2021 Prepared by: ClearLead Consulting Limited The Barn, Cadhay, Ottery St Mary, Devon EX11 1QT www.clearleadconsulting.com 01404 814273 Quality Management Issue/revision Issue 1 Issue 2 Report Status Draft Final Date 23/04/21 28/04/21 Prepared by I Teague I Teague Signature Checked by J Mitchell V Pearson Signature Authorised by J Mitchell V Pearson Signature Project number C0093 LIMITATIONS This report has been prepared by ClearLead Consulting Limited solely for the use of the Client and those parties with whom a warranty agreement has been executed, or with whom an assignment has been agreed. Should any third party wish to use or rely upon the contents of the report, written approval must be sought from ClearLead Consulting Limited; a charge may be levied against such approval. ClearLead Consulting Limited accepts no responsibility or liability for: a) the consequences of this document being used for any purpose or project other than for which it was commissioned, and b) the use of this document by any third party with whom an agreement has not been executed. The work undertaken to provide the basis of this report comprised a study of available documented information from a variety of sources (including the Client) and discussions with relevant authorities and other interested parties. The opinions given in this report have been dictated by the finite data on which they are based and are relevant only to the purpose for which the report was commissioned.
    [Show full text]
  • Leyton Jubilee Park I Marsh Lane Bridge Reconstruction
    http://mspweb.walthamforest.gov.uk/Planning/lg/GFPlanningDocumen... 1 0 JAN 2013 London Borough of Wnltham Forest Leyton Jubilee Park I Marsh Lane Bridge Reconstruction Flood Risl< Assessmen t Highways Mainlenance Group Euvirotunen(al Services LONDON SOUROUGH WALTBAM FOREST Low Hall Depol Argall Avenue Lcylon London E I07AS 1 of 1 23/02/2013 15:19 http://mspweb.walthamforest.gov.uk/Planning/lg/GFPlanningDocumen... ~·!}\( :~ ~ . DOCUMENT CONTROL SHEET Project Name Leyton Jubi ee Park I Marsh Lane Bridge Reconstruction Project TUie Rood Risk Assessment OS Map Rei 537076 E. 186955 N Location Le'yton E17 Orgamsat1on Contact Date Copms Waltham Forest A Prud'homme 24/12/12 1 1 of 1 23/02/2013 15:20 http://mspweb.walthamforest.gov.uk/Planning/lg/GFPlanningDocumen... Leyton Jubilee Park I Marsh Lane Bridge Reconstruction Flood Risk Assessment Contents 1.0 Executive Summary 1 2.0 Location 1 3.0 Geographical Area 1 4.0 Environmont Agency Requirement 2 5.0 Available Information 4 6.0 Flood Risk at Bridge Location 5 7.0 W alkover Survey 5 7.1 Habilats 5 7.2 Protected and Notable Species 5 7.3 Invasive Species 6 8.0 Topographical survey 6 9.0 Utilities Survey 6 10.0 Habitat Survey and Protectod Spoclos Assossment 6 11.0 Flood Risk Assessment, Footbridge Dovelopment and Constrain!$ 7 11.1 Flood Zone 7 11.2 Appropriate uses 7 11 .3 Dimensional Requirements of the Proposed Footbridge 7 11.4 Watercourse Reprofiling and Clearances 8 11.5 Flood Risk AsseSSI)lont and Mitigation 8 Appendices AppendiM A - Drawing No: A308·FRA·01 • Topographical Survey -Drawing No.
    [Show full text]
  • Lee Valley Regional Park Landscape Character Assessment
    LCT C: Urban Valley Floor with Marshlands SPA, which provides a nationally important habitat for overwintering birds. Cultural Influences 4.64 The low-lying land of rich alluvial deposits supported a system of grazing, referred to as the Lammas system5 from the Anglo-Saxon period to the end of the C19th. Grazing rights on the marshes were extinguished by the early C20th and a substantial proportion of the marshlands, with the exception of Walthamstow Marshes, were then modified by industrial activities and landfill, including the dumping of bomb rubble after WW2. In the 1950 and 60s the construction of flood relief channels ended the periodic inundation of the marshlands. 4.65 Communication routes through the valley floor proliferated over the C20th, including pylons, roads and railway lines mounted on embankments, but residential and industrial development remains largely confined to the margins. 4.66 Public access and recreation now characterises much of the marshlands, with some areas managed as nature reserves. However substantial infrastructure, such as the railway lines and flood relief channels and adjacent industrial development, means access through and into the marshes from surrounding urban areas is often severed. The tow-path following the River Lee Navigation provides a continuous link along the valley for visitors to enjoy the landscape. 5 A system of grazing whereby cattle was grazed only after the cutting and collection of hay Lee Valley Regional Park Landscape Strategy 85 April 2019 LCA C1: Rammey Marsh Lee Valley Regional Park Landscape Strategy 86 April 2019 LCA C1: Rammey Marsh Occasional long views out to wooded valley sides between Residential properties overlooking the southern area across the riverside vegetation.
    [Show full text]
  • List of Buildings Files Containing Secondary Sources
    Waltham Forest Local Studies Library- List of Buildings files containing secondary sources. Please note this list is a work in progress and some building files contain limited information. Searchroom access is by appointment only. Telephone: 020 8496 4381 or email: [email protected]. Buildings File (always check at 72.2 as well) Name Other Dates File started Abbey Injection Moulding Company, Higham’s Park 1986 Abrahams Estate see Great House & Estates, Leyton E10 Adoption Society Orphanage see Hutchison House, Browning Road, Leytonstone African Caribbean Centre, Ive Farm Lane, Leyton closed 2000 Ainslie House, 140 Chingford Mount Rd, E4 Ainslie Wood Farm see Rolls (or Rolles) Ainslie Wood Gardens Albert Road, E10 (No. 170) Built c1896 by Abrahams 2014 Albert Whicher House, 46-80 Church Hill Road E17 Built c1962 2014 Aldriche Way Estate Aldridge, Laurie (glassworks), Leyton 1986 Alice Burrell Centre, Sidmouth Road, Leyton (for adults with learning difficulties) 1996 Alliston House, Church Hill Road, Walthamstow (Old people’s 2003 home) Alpha Business Centre, South Grove E17 see also South Grove, demolished 2017 1992 Alpha Road (sheltered scheme), Chingford al-Tawhid Mosque see Leyton high Road Mosque Amman Temple see Hindu Temple, 271 Forest Road E17 Amenia Cottage, West Avenue, E17 (built c 1860) Ancient House, Church Lane E17 (2 files) Arcade Shopping Centre, E17 see also Cleveland Place Army Sports Ground, Leyton 1925 ASDA, 1 Leyton Mills, Marshall Road (opened 2001) previously National School, from 2016 Waltham Asian Centre, Orford Road E17 Forest Community Hub Asian Cricket Club, Low Hall Park (opened 1970) Assembly House, Whipps Cross Road see L72.2 Assembly Row/ Forest Place see L72.2, see also Whipps Cross Road Austinsuite (furniture company), Argall Avenue Estate, Leyton (closed 1986) Last updated 15/18/2019 1 Waltham Forest Local Studies Library- List of Buildings files containing secondary sources.
    [Show full text]
  • Thameswater Tida L T Hames Defence Levels Preliminary Report on River Lee Flows and Levels
    ThamesWater Tida l T hames Defence Levels Preliminary Report on River Lee Flows and Levels August 1987 A R CHI VE : PLEA SE D O N OT DES TR O Y ThamesWater Tidal T ha mes Defe nce Levels Preliminary Report on River Lee Flows and Levels August 1987 Sir William Ha !crow & Partners Ltd Institute of Hydrology PREL IMINARY RIVER LEE ANALYSIS CONTENT S Page No GLOSSARY SUMMA RY 1. INTRODUCT ION 1 1.1 Objectives 1 1.2 The Lower River Lee Sys tem , 1 1.3 Da ta Availability 2 2 . DATA COLLECT ION 3 2.1 Tida l Wa ter Level Data 3 2 .2 Flood Da ta for the Lower Lee and Tribu taries 3 2 .3 Sub-catchment Area s 3 2 .4 Urban Area s 4 3 . TR END ANALYSES 5 3 .1 Water Leve l Trend s 5 3 .2 Flood Trend s 5 4 . FREQUENCY ANA LY SES OF T IDAL WATER LEVELS 6 4 .1 Frequen cy of Tida l Wa ter Leve ls 6 4 .2 Adj ustment to Lee Mouth 6 7 . FLOOD FREQUENC IES AT RIV ER GAUGING STAT IONS ON THE LOW ER LEE 7 5 .1 General Approach 7 5.2 Flood Frequencies Based on Data Ana lyses 7 5.3 Flood Frequencies Using FSR P rocedures 8 5.4 Propo sed Flood Frequenc ies for Ga uging Station s 9 6 . FLOOD FREQUENC IES IN LOW ER LEE CHA NNELS 10 6 .1 Flood Freq uencies in Lee Flood Relie f Channe l 10 6 .2 Flood Frequenc ies in Lee Nav iga tion Chan ne l 11 FIGURES 1.1 Diagramma tic Sys tem o f the Lower Lee 3.1 Flood Trends 4 .1 Concurren t Peak Water Leve ls at Brunsw ick Wha rf and Tow er P ier 5 .1 Feildes Weir Con current Flood s , Instan taneous and Mean Da ily 5.2 Flood Frequency Ana ly ses 5.3 G row th Fac to rs fo r Main Lee 5.4 G rowth Fac tors fo r Low er Lee Tributaries
    [Show full text]
  • London in the Thames Catchment
    NOT PROTECTIVELY MARKED London in the Thames catchment Business Case: Flood Risk and the six year investment programme London in the Thames catchment 1. Summary, Headline facts and statistics London’s flood risk Surface Water Rivers/Sea Residential Non Total Residential Non Total residential residential High 59,000 7,000 66,000 11,000 3,000 14,000 Medium 96,000 13,000 109,000 29,000 5,000 34,000 Low 445,000 54,000 499,000 423,000 56,000 485,000 Total at 600,000 74,000 674,000 465,000 65,000 536,000 risk The Six Year Investment Programme The Thames Regional Flood & Coastal Committee decide (RFCC) which projects make up the programme. The allocation of central Government funding to the projects is based on Defra Policy. £180m of Flood Defence Grant in Aid (FD GiA) investment planned in the Thames Estuary to maintain the World Class standard of protection for London from tidal flooding. £77m of FD GiA investment within London in the next six years to directly protect 10,000 properties from tidal flooding £36m of FD GiA investment planned to reduce the risk of river and surface water flooding to 6,800 properties in London At least £25m of contributions are required to unlock all of this investment over the next six years. Levy provides a mechanism for local authorities to pool resources to achieve this. The return on the investment in flood risk management is high. Within Thames the average benefit to cost ratio’s for schemes within the six year investment programme are; Protecting London from tidal flooding: 117:1 Reducing the risk from river flooding: 10:1 Reducing the risk from surface water flooding: 7:1 Levy The levy is used only to part-fund capital projects led by either local authorities or the Environment Agency.
    [Show full text]