Local Flood Risk Management Strategy
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Denbighshire Local Flood Risk Management Strategy June 2014 Denbighshire County Council DenbighshECP ECPire LocalECP ECPFlood Risk Management Strategy 2013 - 2017 Denbighshire County Council Denbighshire County Council Department of Highways and Infrastructure Caledfryn Smithfield Road Denbighshire County Council LL16 3RJ Denbighshire Local Flood Risk Management Strategy Issue and revision record Document Title Local Flood Risk Management Strategy – Consultation Document Version 0.2 Status Final Document version Notes Date 0.1 Public Consultation January 2014 0.2 Final Version June 2014 Signature Name Date Prepared by A. Bebbington 27/6/14 Checked by W. Hope 27/6/14 Approved by W. Hope 27/6/14 This document is issued for the party which commissioned it We accept no responsibility for the consequences of this and for specific purposes connected with the above-captioned document being relied upon by any other party, or being used project only. It should not be relied upon by any other party or for any other purpose, or containing any error or omission which used for any other purpose. is due to an error or omission in data supplied to us by other parties. This document contains proprietary intellectual property. It should not be used by other parties without consent from us and from the party which commissioned it. Copyright of Denbighshire County Council Denbighshire Local Flood Risk Management Strategy Denbighshire Local Flood Risk Management Strategy Content Chapter Title Page Glossary and Abbreviations of words and phrases commonly used in flood and coastal erosion risk management ____ Foreword Executive Summary ii 1. Introduction 1 1.1 Introduction ________________________________________________________________________ 1 1.2 Lessons learnt from the November 2012 Floods ___________________________________________ 1 1.3 Structure of the Local Strategy _________________________________________________________ 1 1.4 Strategic Environmental Assessment ____________________________________________________ 2 1.5 Habitats Regulations Assessments ______________________________________________________ 2 2. Legislative Context 3 2.1 History of Flood Risk Management ______________________________________________________ 3 2.2 The Flood and Water Management Act 2010 ______________________________________________ 4 2.3 The Pitt Review _____________________________________________________________________ 4 2.4 The Flood Risk Regulations 2009 _______________________________________________________ 4 2.5 The National Strategy for Flood and Coastal Erosion Risk Management _________________________ 5 2.6 Other Legislation ____________________________________________________________________ 6 3. Flood Risk in Denbighshire 7 3.1 Introduction ________________________________________________________________________ 7 3.2 Local Flood Risk ____________________________________________________________________ 7 3.3 Types of Flooding ___________________________________________________________________ 9 3.3.1 Surface Water Flooding (pluvial) _______________________________________________________ 11 3.3.2 Groundwater Flooding ______________________________________________________________ 11 3.3.3 Fluvial Flooding ____________________________________________________________________ 12 3.3.4 Sewer or Highway Flooding __________________________________________________________ 13 3.3.5 Reservoir Flooding _________________________________________________________________ 13 3.3.6 Coastal Flooding ___________________________________________________________________ 14 3.4 Canal Flooding ____________________________________________________________________ 14 3.5 A Combination Event _______________________________________________________________ 14 3.6 Coastal Squeeze ___________________________________________________________________ 15 3.7 Factors Increasing Flood Risk _________________________________________________________ 16 3.8 Methodology for Identifying Areas of Risk ________________________________________________ 16 3.9 Limitations of data __________________________________________________________________ 17 4 Climate Change 18 4.1 Climate Change ___________________________________________________________________ 18 4.2 Climate Change in Wales ____________________________________________________________ 19 4.3 Key Projections for Western Wales River Basin District _____________________________________ 19 4.4 Key Projections for Dee River Basin District ______________________________________________ 20 4.5 Implications for Flood Risk ___________________________________________________________ 20 Denbighshire Local Flood Risk Management Strategy 5 Regional and Local Plans 21 5.1 Denbighshire County Council Preliminary Flood Risk Assessment ____________________________ 21 5.2 Conwy and Clwyd Catchment Flood Management Plan _____________________________________ 22 5.3 River Dee Catchment Flood Management Plan ___________________________________________ 22 5.4 North West England and North Wales Shoreline Management Plan SMP2 ______________________ 22 5.5 River Basin Management Plan – Western Wales River Basin District and Dee River Basin District ____ 23 5.6 Denbighshire Strategic Flood Consequence Assessment ___________________________________ 23 5.7 The Tidal Clwyd Flood Risk Management Strategy ________________________________________ 24 5.8 Rhyl – Prestatyn Coastal Defence Strategy Study Report ___________________________________ 24 6 Managing the Likelihood of Flooding 25 6.1 Responsibilities of Natural Resources Wales _____________________________________________ 26 6.1.1 Coastal Erosion Risk Management Authority _____________________________________________ 27 6.1.2 Emergency Planning ________________________________________________________________ 27 6.1.3 Main Rivers _______________________________________________________________________ 28 6.1.4 Coastal __________________________________________________________________________ 28 6.1.5 Reservoirs ________________________________________________________________________ 29 6.2 Powers and Responsibilities of Denbighshire County Council ________________________________ 30 6.2.1 Highways & Environmental Services ___________________________________________________ 32 6.2.1.1 Strategic Leadership ________________________________________________________________ 32 6.2.1.2 Recording of Flood Incidents _________________________________________________________ 33 6.2.1.3 Investigation of Flood Incidents________________________________________________________ 33 6.2.1.4 Register of Flood Risk Assets _________________________________________________________ 35 6.2.1.5 Sustainable development ____________________________________________________________ 35 6.2.1.6 Designating Assets _________________________________________________________________ 35 6.2.1.7 Meeting the Flood Risk Regulations ____________________________________________________ 35 6.2.1.8 Consenting Works on Ordinary Watercourses ____________________________________________ 36 6.2.1.9 As SuDS Approval Body (SAB) ________________________________________________________ 36 6.2.3 Joint Emergency Planning Unit ________________________________________________________ 37 6.2.4 As a Planning Authority ______________________________________________________________ 40 6.2.4.1 Strategic Planning/Planning Policy Function ______________________________________________ 40 6.2.4.2 Development Control Function ________________________________________________________ 40 6.3 Water and Sewage Companies _______________________________________________________ 41 6.3.1.1 Dŵr Cymru – Welsh Water ___________________________________________________________ 41 6.3.1.2 Dee Valley Water __________________________________________________________________ 42 6.3.2 Flood Risk Management _____________________________________________________________ 42 6.4 Denbigshire County Council as a Highways Authority ______________________________________ 43 6.4.1 Responsibility to maintain the Highways _________________________________________________ 44 6.4.2 Adoption of SuDS __________________________________________________________________ 44 6.4.3 Powers to deliver works _____________________________________________________________ 45 6.4.4 Response in an Emergency Flooding Event ______________________________________________ 45 6.4.5 North and Mid Wales Trunk Road Agency on behalf of the Welsh Government ___________________ 46 6.4.6 Powers and Responsibilities of Denbighshire’s Citizens (Businesses, Landowners and Local Households) _ 47 Property Owners and Residents __________________________________________________________________ 47 6.4.7 Riparian Ownership ________________________________________________________________ 48 6.4.8 Utility and Infrastructure Providers _____________________________________________________ 48 6.4.9 Reservoir Undertaker _______________________________________________________________ 49 6.5 Other Bodies ______________________________________________________________________ 49 Denbighshire Local Flood Risk Management Strategy 7 Local Objectives and Measures 50 7.1 Denbighshire County Council’s Flood Risk Management Objectives ___________________________ 50 7.2 Outcomes from Denbighshire County Council’s Objectives : __________________________________ 51 7.3 Potential Measures _________________________________________________________________ 53 7.4 Compatibility Matrix _________________________________________________________________ 71 7.5 Adopt