SWRBD CFRAM Study
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SWRBD CFRAM Study Inception Report - Unit of Management 18 September 2013 Office of Public Works SWRBD296235 IWECFRAM CCW StudyR003 C 296235/IWE/CCW/R003/C February 2013 Inception Report - Unit of Management 18 September 2013 Office of Public Works Jonathan Swift Street Trim Co. Meath SWRBD CFRAM Study Issue and Revision Record Revision Date Originator Checker Approver Descript ion A May 2012 M. Piggott B. O’Connor F. McGivern Initial Issue T. Donovan B November 2012 M. Piggott B. O’Connor F. McGivern Revised Issue T. Donovan C February 2013 M. Piggott B. O’Connor F. McGivern Revised Issue A. Lambe D May 2013 T. Donovan B. O’Connor F. McGivern Revised Issue E September 2013 T. Donovan B. O’Connor F. McGivern Revised Issue Please read carefully the following statements and conditions of use of the data, contained in this report. Accessing the information and data denotes agreement to, and unconditional acceptance of, all of the statements and conditions. 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No part used for any other purpose. of this report may be copied or reproduced by any means without prior written permission from the Office of Public Works. We accept no responsibility for the consequences of this document being relied upon by any other party, or being used Legal Disclaimer for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other This report is subject to the limitations and warranties contained parties in the contract between the commissioning party (Office of Public Works) and Mott MacDonald Ireland. This document contains confidential information and proprietary intellectual property. It should not be shown to other parties without consent from us and from the party which commissioned it. 296235/IWE/CCW/R003/E 296235-IWE-CCW-R003-E HA18.doc SWRBD CFRAM Study Content Chapter Title Page 1. Introduction 1 1.1 Aims and Objectives _________________________________________________________________ 1 1.2 Description of the South Western Study Area ______________________________________________ 2 1.3 Unit of Management 18 _______________________________________________________________ 4 1.4 Areas for Further Assessment _________________________________________________________ 4 1.5 SW CFRAMs Project Delivery __________________________________________________________ 4 2. Data Availability and Requirements 6 2.1 Data Collection _____________________________________________________________________ 6 2.2 Hydrometric Data ___________________________________________________________________ 6 2.3 Meteorological Data _________________________________________________________________ 6 2.4 Coastal Data _______________________________________________________________________ 7 2.5 Survey Data (including LIDAR & IFSAR) _________________________________________________ 7 2.6 Environmental Data _________________________________________________________________ 7 2.7 Receptor Data ______________________________________________________________________ 9 2.8 Flood Event Data __________________________________________________________________ 11 2.9 Flood Defence Asset Data ___________________________________________________________ 12 2.10 Outstanding Data __________________________________________________________________ 13 2.11 Unavailable Data ___________________________________________________________________ 14 3. Survey Requirements 15 3.1 River Channel Survey _______________________________________________________________ 15 3.2 Floodplain Survey __________________________________________________________________ 16 3.3 Flood Defence Asset Condition Survey _________________________________________________ 16 3.4 Property Level Survey _______________________________________________________________ 18 4. Preliminary Hydrological Assessment 19 4.1 Hydrometric Data Review ____________________________________________________________ 19 4.2 Metrological Data Review ____________________________________________________________ 22 4.3 Coastal Data Review _______________________________________________________________ 24 4.4 Physical Catchment Descriptor Review _________________________________________________ 24 4.5 Historical Flood Events ______________________________________________________________ 26 4.5.1 Review of Historical Flood Data _______________________________________________________ 26 4.5.2 Historical Flood Event Summaries _____________________________________________________ 26 4.5.3 Selection of Calibration/Verification Events ______________________________________________ 31 4.6 Flooding Mechanisms _______________________________________________________________ 32 5. Detailed Method Statement 34 5.1 Flood Risk Review Approach _________________________________________________________ 34 5.1.1 Site Visits ________________________________________________________________________ 34 5.1.2 Flooding History ___________________________________________________________________ 34 5.1.3 Flood Risk Review Report____________________________________________________________ 34 5.2 Survey Approach __________________________________________________________________ 34 5.2.1 Channel and Structure Survey ________________________________________________________ 34 5.2.2 Defence Asset Condition Survey ______________________________________________________ 34 296235/IWE/CCW/R003/E 296235-IWE-CCW-R003-E HA18.doc SWRBD CFRAM Study 5.3 Hydrology Approach ________________________________________________________________ 35 5.3.1 Overview _________________________________________________________________________ 35 5.3.2 HEP Conceptualisation ______________________________________________________________ 37 5.3.3 Rating Reviews ____________________________________________________________________ 38 5.3.4 Approach for Gauged Fluvial Locations _________________________________________________ 40 5.3.5 Approach for Ungauged Fluvial Locations _______________________________________________ 42 5.3.6 Approach for Tidal Locations _________________________________________________________ 43 5.3.7 Future Scenarios ___________________________________________________________________ 45 5.4 Hydraulic Analysis Approach _________________________________________________________ 46 5.5 Flood Risk Assessment (FRA) ________________________________________________________ 50 5.5.1 Social Risk _______________________________________________________________________ 51 5.5.2 Risk to the Environment _____________________________________________________________ 51 5.5.3 Risk to Cultural Heritage _____________________________________________________________ 51 5.5.4 Risk to the Economy ________________________________________________________________ 51 5.5.5 Indicators of Vulnerability ____________________________________________________________ 52 5.5.6 Risk Assessments __________________________________________________________________ 52 5.6 Strategic Environmental Assessment (SEA) ______________________________________________ 52 5.6.1 Phase I Screening Assessment _______________________________________________________ 52 5.6.2 Phase II Constraint and SEA Scoping Study _____________________________________________ 52 5.6.3 Phase III Option Appraisal Study ______________________________________________________ 53 5.6.4 Phase IV SEA Report _______________________________________________________________ 54 5.6.5 Phase V Update of SEA Report _______________________________________________________ 54 5.6.6 Production of the SEA Statement ______________________________________________________ 54 5.7 Appropriate Assessment _____________________________________________________________ 54 5.8 Development of Flood Risk Management Options