North West river basin district Flood Risk Management Plan 2015 to 2021 PART B – Sub Areas in the North West river basin district March 2016 1 of 139 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: [email protected] or our National Customer Contact Centre: www.gov.uk/environment-agency T: 03708 506506 Email: [email protected]. © Environment Agency 2016 All rights reserved. This document may be reproduced with prior permission of the Environment Agency. 2 of 139 Contents Glossary and abbreviations ......................................................................................................... 5 The layout of this document ........................................................................................................ 8 1 Sub-areas in the North West River Basin District ......................................................... 10 Introduction ............................................................................................................................ 10 Management Catchments ...................................................................................................... 11 Flood Risk Areas ................................................................................................................... 11 2 Conclusions and measures to manage risk for the Flood Risk Areas in the North West River Basin District ................................................................................................ 12 2.1 The Greater Manchester Flood Risk Area ...................................................................... 13 Introduction to the Greater Manchester Flood Risk Area ........................................................ 13 Flood risk maps and statistics ................................................................................................ 15 Conclusions for the Greater Manchester Flood Risk Area ...................................................... 16 Measures across the Greater Manchester Flood Risk Area ................................................... 18 2.1 Liverpool and Sefton Flood Risk Area ........................................................................... 21 Introduction to the Liverpool and Sefton Flood Risk Area ....................................................... 21 Flood risk maps and statistics ................................................................................................ 24 Conclusions for the Liverpool and Sefton Flood Risk Area ..................................................... 25 Measures across the Liverpool and Sefton Flood Risk Area .................................................. 26 3 Conclusions and measures to manage risk in North West River Basin District catchments ...................................................................................................................... 28 3.2 The Derwent Catchment .................................................................................................. 31 Introduction to the catchment ................................................................................................. 31 Flood risk maps and statistics ................................................................................................ 34 Conclusions for the Derwent Catchment ................................................................................ 37 Measures across the Derwent Catchment ............................................................................. 38 3.2 The South West Lakes Catchment ................................................................................. 40 Introduction to the catchment ................................................................................................. 40 Flood risk maps and statistics ................................................................................................ 43 Conclusions for the South West Lakes Catchment................................................................. 46 Measures across the South West Lakes Catchment .............................................................. 47 3.3 The Kent and Leven Catchment ..................................................................................... 49 Introduction to the catchment ................................................................................................. 49 Flood risk maps and statistics ................................................................................................ 52 Conclusions for the Kent and Leven Catchment .................................................................... 55 Measures across the Kent and Leven Catchment .................................................................. 57 3.4 The Lune Catchment ....................................................................................................... 59 Introduction to the catchment ................................................................................................. 59 Flood risk maps and statistics ................................................................................................ 61 Conclusions for the Lune Catchment ..................................................................................... 64 3 of 139 Measures across the Lune Catchment ................................................................................... 65 3.5 The Wyre Catchment ....................................................................................................... 67 Introduction to the catchment ................................................................................................. 67 Flood risk maps and statistics ................................................................................................ 71 Conclusions for the Wyre Catchment ..................................................................................... 74 Measures across the Wyre Catchment .................................................................................. 76 3.6 The Ribble Catchment ..................................................................................................... 78 Introduction to the catchment ................................................................................................. 78 Flood risk maps and statistics ................................................................................................ 80 Conclusions for the Ribble Catchment ................................................................................... 83 Measures across the Ribble Catchment ................................................................................. 84 3.7 The Douglas Catchment .................................................................................................. 86 Introduction to the catchment ................................................................................................. 86 Flood risk maps and statistics ................................................................................................ 89 Conclusions for the Douglas Catchment ................................................................................ 92 Measures across the Douglas Catchment .............................................................................. 93 3.8 The Alt Crossens Catchment .......................................................................................... 95 Introduction to the catchment ................................................................................................. 95 Flood risk maps and statistics ................................................................................................ 98 Conclusions for the Alt Crossens Catchment ....................................................................... 101 Measures across the Alt Crossens Catchment ..................................................................... 102 3.9 The Irwell Catchment ..................................................................................................... 104 Introduction to the catchment ............................................................................................... 104 Flood risk maps and statistics .............................................................................................. 107 Conclusions for the Irwell Catchment ................................................................................... 109 Measures across the Irwell Catchment ................................................................................ 111 3.10 The Upper Mersey Catchment ...................................................................................... 113 Introduction to the catchment ............................................................................................... 113 Flood risk maps and statistics .............................................................................................. 116 Conclusions for the Upper Mersey Catchment ..................................................................... 118 Measures across the Upper Mersey Catchment .................................................................. 120 3.11 The Lower Mersey Catchment ...................................................................................... 121 Introduction to the catchment ............................................................................................... 121 Flood risk maps and