Thames River Basin District Flood Risk Management Plan 2015- 2021 PART B – sub areas in the Thames river basin district March 2016 Page 1 of 153 Published by: Environment Agency Further copies of this report are available Horizon house, Deanery Road, from our publications catalogue: Bristol BS1 5AH www.gov.uk/government/publications Email: enquiries@environment- or our National Customer Contact Centre: agency.gov.uk T: 03708 506506 www.gov.uk/environment-agency Email: [email protected]. © Environment Agency 2016 All rights reserved. This document may be reproduced with prior permission of the Environment Agency. Page 2 of 153 Contents Glossary and abbreviations ......................................................................................................... 6 The format of the flood risk management plan ........................................................................... 9 1. Sub-areas in the Thames river basin district ........................................................................ 11 Introduction ..................................................................................................................... 11 Flood risk areas ............................................................................................................... 11 Management catchments ................................................................................................ 11 Strategic areas ................................................................................................................ 12 2. Conclusions, objectives and measures to manage risk for the flood risk areas in Thames river basin district ......................................................................................................... 23 2.1 The London flood risk area .................................................................................................. 23 Introduction to the London flood risk area ........................................................................ 23 Flood risk statistics .......................................................................................................... 26 Conclusions and objectives for the London flood risk area .............................................. 29 Measures across the London flood risk area ................................................................... 30 2.2 The Medway flood risk area ................................................................................................. 32 Introduction to the Medway flood risk area ...................................................................... 32 Flood risk statistics .......................................................................................................... 33 Conclusions and objectives for the Medway flood risk area ............................................. 35 Measures across the Medway flood risk area .................................................................. 35 3. Conclusions, objectives and measures to manage risk in the Thames river basin district catchments ..................................................................................................................... 37 3.1 The Cherwell and Ray catchment ........................................................................................ 38 Introduction to the Cherwell and Ray catchment .............................................................. 38 Flood risk statistics .......................................................................................................... 40 Conclusions and objectives for the Cherwell and Ray catchment .................................... 41 Measures across the Cherwell and Ray catchment ......................................................... 42 3.2 The Colne catchment ............................................................................................................ 44 Introduction to the Colne catchment ................................................................................ 44 Flood risk statistics .......................................................................................................... 46 Conclusions and objectives for the Colne catchment ....................................................... 47 Measures across the Colne catchment ............................................................................ 48 3.3 The Cotswolds catchment .................................................................................................... 50 Introduction to the Cotswolds catchment ......................................................................... 50 Flood risk statistics .......................................................................................................... 52 Conclusions and objectives for the Cotswolds catchment ................................................ 53 Measures across the Cotswolds catchment ..................................................................... 54 3.4 The Darent and Cray catchment .......................................................................................... 56 Page 3 of 153 Introduction to the Darent and Cray catchment ................................................................ 56 Flood risk statistics .......................................................................................................... 59 Conclusions and objectives for the Darent and Cray catchment ...................................... 60 Measures across the Darent and Cray catchment ........................................................... 61 3.5 The Gloucestershire and the Vale catchment ..................................................................... 63 Introduction to the Gloucestershire and the Vale catchment ............................................ 63 Flood risk statistics .......................................................................................................... 65 Conclusions and objectives for the Gloucestershire and the Vale catchment................... 66 Measures across the Gloucestershire and the Vale catchment ....................................... 67 3.6 The Kennet and tributaries catchment ................................................................................ 69 Introduction to the Kennet and tributaries catchment ....................................................... 69 Flood risk statistics .......................................................................................................... 71 Conclusions and objectives for the Kennet and tributaries catchment ............................. 72 Measures across the Kennet and tributaries catchment .................................................. 73 3.7 The Loddon and tributaries catchment ............................................................................... 75 Introduction to the Loddon and tributaries catchment ...................................................... 75 Flood risk statistics .......................................................................................................... 77 Conclusions and objectives for the Loddon and tributaries catchment ............................. 78 Measures across the Loddon and tributaries catchment .................................................. 79 3.8 The London catchment ......................................................................................................... 81 Introduction to the London catchment .............................................................................. 81 Flood risk statistics .......................................................................................................... 83 Conclusions and objectives for the London catchment .................................................... 84 Measures to manage risk across the London catchment ................................................. 87 3.9 The Maidenhead to Sunbury catchment .............................................................................. 89 Introduction to the Maidenhead to Sunbury catchment .................................................... 89 Flood risk statistics .......................................................................................................... 91 Conclusions and objectives for the Maidenhead to Sunbury ............................................ 92 Measures across the Maidenhead to Sunbury catchment ............................................... 93 3.10 The Medway catchment ...................................................................................................... 95 Introduction to the Medway catchment ............................................................................ 95 Flood risk statistics .......................................................................................................... 98 Conclusions and objectives for the Medway catchment ................................................... 99 Measures across the Medway catchment ...................................................................... 100 3.11 The Mole catchment .......................................................................................................... 102 Introduction to the Mole catchment ................................................................................ 102 Flood risk statistics ........................................................................................................ 104 Conclusions and objectives for the Mole catchment ...................................................... 105 Measures across the