Environment Agency Kent Area I Autumn 2000 Floods Review Rea Report
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Environment Agency Kent Area i Autumn 2000 Floods Review rea Report E n v ir o n m e n t Southern Region Ag en c y E n v ir o n m e n t Ag e n c y NATIONAL LIBRARY & INFORMATION SERVICE SOUTHERN REGION Guildbourne House. Chatsworth Road, Worthing. West Sussex BN 1 1 1LD Published by: Environment Agency Rio House Waterside Drive Aztec West Almondsbury Bristol BS32 4UD Tel: 01454 624400 Fax: 01454 624409 www.environment-agency.gov.uk ISBN 1 -85-705668-X © Environment Agency All rights reserved. No part of this document may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise without prior permission of the Environment Agency. Printed on recycled paper Environment Agency Kent Ai XX) Floods Review FOREWORD The dramatic events experienced last winter have deeply affected all those involved. The extent of the flooding and speculation regarding climate change have devastated the confidence of those living in flood risk areas, the effects of which will be felt long after the physical damage has been repaired. We must now work together to face up to the challenge of managing the risk of flooding. To ensure that the Environment Agency delivers the best possible service to our customers, it is essential that we continually review our performance to identify any areas for improvement. This report has been produced to provide an accurate and clear understanding of the events that occurred during the Autumn floods in the Kent Area. Throughout the report issues are raised and recommendations have been made. From the list of recommendations an Action Plan will be produced in order to address the recommendations proposed. The Action Plan will include a detailed programme for introducing the improvements. We expect to produce the Action Plan by August 2001. In the meantime, much is being done to repair the defences damaged over the Autumn and Winter period and to increase the number of people who receive warnings directly from ourselves. Copies of this review are being circulated to interested groups including Local Authorities, Emergency Services, Local MPs and members of the public on request. If you would like further information relating to content of this review, we would welcome your written comments at the address below. Andrew Pearce Kent Area Flood Defence Manager July 2001 Andrew Pearce Kent Area Flood Defence Manager Orchard House Addington Kent ME19 5SH ENVIRONMENT AGENCY 9 0845 933 3111 1 01732 875 057 062142 S [email protected] Version 1.0 Page i 19/08/01 Environment Agency Kent Area Autumn 2000 Floods Review Kent Area J ^ * °NMENT autum n 2000 FLOODS IN SOUTHERN REGION FLOOD EVENTS 15 SEPTEMBER -15 NOVEMBER No Properties Flooded Hampshire and Isle of ■ Up to 20 Wight Area | >20 to <100 100 or greater ^ R e g io n a l WM Boundary w Main River Urban Areas MAP 1.1 R*S»\G«_P«OJECTS\OCT_Fl DJVTCMTT Version 1.0 Page ii 19/08/01 Environment Agency Kent Area Autumn 2000 Floods Review CONTENTS 1 Executive Summary........................................................................................ 1-1 2 Flood Forecasting and Hyrdological Response............................................2-1 2.1 Forecasting............................................................................................. 2-1 2.2 Rainfall...................................................................................................2-4 2.3 River Flows............................................................................................2-6 2.4 Issues and Recommendations............................................................... 2-16 3 Flood Warning.................................................................................................3-1 3.1 Trigger/Threshold Levels for Warnings................................................. 3-1 3.2 Trigger levels for Specific Sites............................................................. 3-2 3.3 Warnings Issued.....................................................................................3-2 3.4 Automated Voice Messaging (AVM) Use and Effectiveness.................3-3 3.5 AVM Availability and Reliability...................................... .'............ ......3-4 3.6 ‘Floodline’..............................................................................................3-4 3.7 Issues Arising and Recommendations.................................................... 3-6 4 Emergency Response/Standards of Defence................................................ 4-1 4.1 Major Incident Plans Activated.............................................................. 4-1 4.2 Gold and Silver Controls with Agency Attendance............................... 4-1 4.3 Agency (staffing, equipment and plant)..................................................4-2 4.4 Adequacy of Agency Resources............................................................. 4-4 4.5 Numbers of Staff Deployed.................................................................... 4-4 4.6 Range of Functions and inter Regional Co-Operation........................... 4-5 4.7 Emergency Services, Local Authority, Other Response Organisations.. 4-5 4.8 Property evacuated (no. of people) and type.......................................... 4-6 4.9 Issues And Recommendations................................................................ 4-8 5 Event Impact and Data Collection................................................................ 5-1 5.1 Sources of Flooding................................................................................5-1 5.2 Number of Properties not Flooded due to Agency Defences................. 5-7 5.3 Number of Properties not Flooded due to Third Party Defences............5-8 5.4 Number of Properties Flooded due to Failure (not exceedence) of Agency Defences.................................................................................................5-9 5.5 Number of Properties Flooded due to Failure (not exceedence) of Third Party Defences........................................................................................5-9 5.6 Number of Properties Flooded due to Exceedence of Agency Defence Standards................................................................................................5-9 5.7 List of Towns Affected Without Adequate Defences............................5-9 5.8 Major Infrastructure Affected..............................................................5-10 5.9 Incidence of Repeat Flooding...............................................................5-11 5.10 Issues and Recommendations...............................................................5-12 6 Subsequent Events of Importance................................................................. 6-1 6.1 December 2000.......................................................................................6-1 6.2 January 2001...........................................................................................6-1 6.3 February 2001.........................................................................................6-1 6.4 Rivers Affected.......................................................................................6-2 6.5 Operational response..............................................................................6-9 6.6 Issues and Recommendations...............................................................6-11 Version 1.0 Page iii 13/08/01 Environment Agency Kent Area Autumn 2000 Floods Review APENDICES Appendix A : Development in the Floodplain Appendix B : Public Response Appendix C : History of Flooding Appendix D : Views of Professional Partners Appendix E : Telemetry Appendix F : Severe Flood Warnings Issued Appendix G : A VM Statistics Appendix H : Rainfall Isohyets FIGURES Figure 2.1: An Aerial view o f Penshurst on Friday 13th October 2000 at the confluence between the River Eden with the River Medway...................................................................................................................2-6 Figure 2.2: An aerial view of the Leigh Barrier in operation on the afternoon of the 12 th October 2000 ..................................................................................................................................................................................2-7 Figure 2.3: View across the floodplain of the River Medway with the Hop Farm at Stilstead in the distance...................................................................................................................................................................2-7 Figure 5.1: The High Street bridge in Yalding with the River Beult in flood. .........................................5-1 Figure 5.2: One of the culverts taking the River Rother flood flows beneath the A21 bypass embankment downstream of Robertsbridge................................................................................................... 5-2 Figure 5.3: Aerial view of the River Medway floodplain downstream of Tonbridge 13th October......5-4 Figure 5.4: Aerial view o f Colliers Land bridge on the Upper Medway, the gauging station is a key element of the Leigh Barrier operating system..............................................................................................5-5 Figure 5.5: General view of Yalding. The River Beult is in the foreground............................................5-5 Figure 5.6:Aerial view of the River Teise and the Lesser Teise on Friday 13°' October, showing Colliers Street and