RIVER DODDER CATCHMENT FLOOD RISK MANAGEMENT PLAN · A. Jackson A. Jackson West Pier 9/7/2010 River...

RIVER DODDER CATCHMENTFLOOD RISK MANAGEMENT PLAN

HYDRAULIC ANALYSIS REPORT

JULY 2010

DOCUMENT CONTROL SHEET

Client Dublin City Council

Project Title River Dodder Catchment Flood Risk Assessment and Management Study

Document Title Hydraulic Analysis Report

Document No. MDW0259Rp0021

DCS TOC Text List of Tables List of Figures No. of Appendices This Document

Comprises 1 1 125 1 1 4

Rev. Status Author(s) Reviewed By Approved By Office of Origin Issue Date

D01 Draft C.O’Donnell B. Elsaesser B. Elsaesser West Pier 01/08/2008

A01 Approval C.O’Donnell B. Elsaesser B. Elsaesser West Pier 16/12/2008

F01 Final C.O’Donnell/ C. Walsh A. Jackson A. Jackson West Pier 9/7/2010

River Dodder Catchment Flood Risk Assessment and

Management Study

Hydraulic Analysis Report

IMPORTANT DISCLAIMER – HYDRAULIC ANALYSIS

Please read below the disclaimer, and limitations associated with this report to avoid incorrect interpretation of the information and data provided. DISCLAIMER Dublin City Council, South Dublin County Council, Dun Laoghaire and Rathdown County Council and The Office of Public Works make no representations, warranties or undertakings about any of the information provided in this report including, without limitation, on its accuracy, completeness, quality or fitness for any particular purpose. To the fullest extent permitted by applicable law, neither the State, Dublin City Council, South Dublin County Council, Dun Laoghaire and Rathdown County Council nor The Office of Public Works nor any of their members, officers, associates, consultants, employees, affiliates, servants, agents or other representatives shall be liable for loss or damage arising out of, or in connection with, the use of, or the inability to use, the information provided in this report including, but not limited to, indirect or consequential loss or damages, loss of data, income, profit, or opportunity, loss of, or damage to, property and claims of third parties, even if Dublin City Council, South Dublin County Council, Dun Laoghaire and Rathdown County Council and The Office of Public Works has been advised of the possibility of such loss or damages, or such loss or damages were reasonably foreseeable. Dublin City Council, South Dublin County Council, Dun Laoghaire and Rathdown County Council and The Office of Public Works reserves the right to change the content and / or presentation of any of the information provided in this report at their sole discretion, including these notes and disclaimer. This disclaimer, guidance notes and conditions of use shall be governed by, and construed in accordance with, the laws of the Republic of Ireland. If any provision of these disclaimer, guidance notes and conditions of use shall be unlawful, void or for any reason unenforceable, that provision shall be deemed severable and shall not affect the validity and enforceability of the remaining provisions. UNCERTAINTY Although great care and modern, widely-accepted methods and modern software packages have been used in undertaking this hydraulic analysis there is inevitably a range of inherent uncertainties and assumptions made during the construction and calibration of the numerical models. These would include:

• An inaccuracies in the topographical and LiDAR survey data. • Selection of roughness values for the river channel and floodplain • Selection of friction coefficients for hydraulic structures • Assumptions in the hydrological analysis.

BEST AVAILABLE INFORMATION The Hydraulic Analysis described in this report used the best available information at the time utilising best practice methodologies and modern software packages but it is acknowledged that new methodologies/revised versions of software and/or recently recorded data could have a minor impact on the predicted flood levels. However under the requirements of the Floods Directive (2007/60/EC), and its transposing legislation (SI 122 of 2010) into Irish law, this report will be reviewed every 6 years and changes to methodologies, software and/or datasets will be incorporated within a subsequent revised version.

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TABLE OF CONTENTS

1 INTRODUCTION........................................................................................................................ 1 1.1 BACKGROUND ................................................................................................................. 1 1.2 OBJECTIVES OF REPORT.................................................................................................. 1

2 DATA COLLECTION ................................................................................................................. 2 2.1 TOPOGRAPHICAL SURVEY DATA ....................................................................................... 2

2.1.1 Existing Survey Data ........................................................................................ 4 2.2 CCTV SURVEY DATA....................................................................................................... 5 2.3 DIGITAL TERRAIN MODEL DATA ........................................................................................ 5 2.4 HYDROLOGICAL DATA ...................................................................................................... 8

3 MODEL CONSTRUCTION......................................................................................................... 9 3.1 1-DIMENSIONAL HYDRAULIC MODELS ............................................................................... 9

3.1.1 River Dodder Main Channel ........................................................................... 10 3.1.2 Tallaght Stream .............................................................................................. 15 3.1.3 Owendoher Stream ........................................................................................ 17 3.1.4 Whitechurch Stream....................................................................................... 18 3.1.5 Little Dargle Stream........................................................................................ 19 3.1.6 Dundrum / Slang Stream................................................................................ 21

3.2 2-DIMENSIONAL HYDRAULIC MODELS ............................................................................. 22 3.2.1 River Dodder Main Channel ........................................................................... 23 3.2.2 Tallaght Stream .............................................................................................. 26 3.2.3 Owendoher Stream ........................................................................................ 27 3.2.4 Whitechurch Stream....................................................................................... 28 3.2.5 Dundrum / Slang Stream................................................................................ 29

3.3 COUPLED HYDRAULIC MODELS ...................................................................................... 32 3.4 MODEL CALIBRATION ..................................................................................................... 33

4 SENSITIVITY ANALYSES....................................................................................................... 35 4.1 COUPLED HYDRAULIC MODEL ........................................................................................ 35

4.1.1 Discharge ....................................................................................................... 35 4.1.2 2-D Model Grid Resolution ............................................................................. 38 4.1.3 Floodplain Resistance .................................................................................... 41 4.1.4 Link Weir Roughness ..................................................................................... 44 4.1.5 Digital Surface Model (DSM) V Digital Terrain Model (DTM)......................... 46

4.2 HIGH END FUTURE SCENARIO ........................................................................................ 48 4.2.1 Dodder Upper ................................................................................................. 48 4.2.2 Dodder Middle ................................................................................................ 51

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4.2.3 Dodder Lower ................................................................................................. 53 4.3 SUMMARY AND CONCLUSIONS........................................................................................ 57

5 FLUVIAL DISCHARGE DESIGN EVENT ANALYSIS ............................................................ 58 5.1 METHODOLOGY.............................................................................................................. 58

5.1.1 Data Analysis.................................................................................................. 58 5.1.2 Joint Probability Analysis................................................................................ 58

5.2 RESULTS....................................................................................................................... 64 5.2.1 Dodder Main Channel and Tallaght Stream................................................... 66 5.2.2 Dodder Main Channel and Dodder Urban 1................................................... 68 5.2.3 Dodder Main Channel and Owendoher / Whitechurch................................... 70 5.2.4 Dodder Main Channel and Little Dargle ......................................................... 73 5.2.5 Dodder Main Channel and Dodder Urban 2................................................... 75 5.2.6 Dodder Main Channel and Dundrum / Slang ................................................. 77 5.2.7 Dodder Main Channel and Dodder Urban 3+4 .............................................. 79 5.2.8 Owendoher and Whitechurch Stream ............................................................ 80

6 DISCHARGE AND TOTAL COASTAL WATER LEVEL JOINT PROBABILITY ANALYSIS 83 6.1 DERIVATION OF EXTREME FLUVIAL DISCHARGES AND JOINT PROBABILITY TOTAL COASTAL

WATER LEVELS.................................................................................................................................... 83 6.1.1 Rainfall and Tidal Surge Joint Probability Analysis ........................................ 84 6.1.2 Relationship between Fluvial Discharge and Rainfall .................................... 87 6.1.3 Relationship between Tidal Surge and Total Water Levels ........................... 88 6.1.4 Design Event Extreme Fluvial Discharge and Total Coastal Water Level ..... 89 6.1.5 Future Scenario.............................................................................................. 90

6.2 DERIVATION OF EXTREME TOTAL COASTAL WATER LEVELS AND JOINT PROBABILITY FLUVIAL

DISCHARGES 92 6.2.1 Relationship between Total Water Levels and Tidal Surge ........................... 92 6.2.2 Rainfall and Tidal Surge Joint Probability Analysis ........................................ 93 6.2.3 Relationship between Fluvial Discharge and Rainfall .................................... 94 6.2.4 Design Event Extreme Total Coastal Water Levels and Fluvial Discharges . 94

7 HYDROGRAPH CONVOLUTION............................................................................................ 96 7.1 TRIBUTARY HYDROGRAPHS............................................................................................ 96

7.1.1 Tallaght NAM Present Day............................................................................. 97 7.1.2 Owendoher NAM Present Day....................................................................... 97 7.1.3 Whitechurch NAM Present Day...................................................................... 98 7.1.4 Little Dargle NAM Present Day ...................................................................... 99 7.1.5 Dundrum NAM Present Day........................................................................... 99 7.1.6 Tallaght URBAN Present Day ...................................................................... 100 7.1.7 Owendoher Whitechurch URBAN Present Day ........................................... 101 7.1.8 Little Dargle URBAN Present Day................................................................ 102 7.1.9 Dundrum URBAN 1+2 Present Day ............................................................. 102

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7.2 DODDER MAIN CHANNEL HYDROGRAPHS...................................................................... 103 7.2.1 Bohernabreena NAM Present Day............................................................... 105 7.2.2 Dodder Main Channel NAM Present Day .................................................... 105 7.2.3 Dodder URBAN 1 Present Day .................................................................... 106 7.2.4 Dodder URBAN 2 Present Day .................................................................... 107 7.2.5 Dodder URBAN 3+4 Present Day ................................................................ 108

8 FLOOD MAPPING ................................................................................................................. 110 8.1 FLOOD MAPPING METHODOLOGY ................................................................................. 111

8.1.1 1-D Flood Mapping Methodology ................................................................. 111 8.2 FLOOD MECHANISMS ................................................................................................... 111

8.2.1 Upper Dodder ............................................................................................... 111 8.2.2 Middle Dodder .............................................................................................. 112 8.2.3 Lower Dodder – Fluvial Scenario ................................................................. 113 8.2.4 Lower Dodder – Tidal Scenario.................................................................... 116 8.2.5 Tallaght Stream ............................................................................................ 116 8.2.6 Owendoher Stream ...................................................................................... 117 8.2.7 Whitechurch Stream..................................................................................... 118 8.2.8 Little Dargle Stream...................................................................................... 120 8.2.9 Dundrum / Slang Stream.............................................................................. 121

9 SUMMARY AND CONCLUSION........................................................................................... 125

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LIST OF FIGURES

Figure 1-1 Flood Damage from Hurricane Charlie.............................................................................. 1 Figure 2-1 Typical Survey Brief Drawing............................................................................................. 2 Figure 2-2 Typical ASCII File .............................................................................................................. 3 Figure 2-3 Typical AutoCAD drawing of river cross-section ............................................................... 3 Figure 2-4 Typical 3D AutoCAD model ............................................................................................... 4 Figure 2-5 Survey Extents................................................................................................................... 7 Figure 3-1 Example Simulation Editor File........................................................................................ 10 Figure 3-2 Dodder Upper 1D Model Extent and Boundary Locations .............................................. 11 Figure 3-3 Dodder Middle 1D Model Extent and Boundary Locations.............................................. 12 Figure 3-4 Dodder Lower – Fluvial Scenario 1D Model Extent and Boundary Locations................. 14 Figure 3-5 Dodder Lower – Tidal Scenario 1D Model Extent and Boundary Locations ................... 15 Figure 3-6 Tallaght Stream 1D Model Extent and Boundary Locations............................................ 16 Figure 3-7 Owendoher Stream 1D Model Extent and Boundary Locations...................................... 18 Figure 3-8 Whitechurch Stream 1D Model Extent and Boundary Locations .................................... 19 Figure 3-9 Little Dargle Stream 1D Model Extent and Boundary Locations ..................................... 20 Figure 3-10 Dundrum / Slang Stream 1D Model Extent and Boundary Locations ......................... 22 Figure 3-11 Dodder Upper 1D and 2D Model Extents.................................................................... 24 Figure 3-12 Dodder Middle 1D and 2D Model Extents................................................................... 25 Figure 3-13 Dodder Lower 1D and 2D Model Extents.................................................................... 26 Figure 3-14 Tallaght Stream 1D and 2D Model Extents................................................................. 27 Figure 3-15 Owendoher Stream 1D and 2D Model Extents ........................................................... 28 Figure 3-16 Whitechurch Stream 1D and 2D Model Extents.......................................................... 29 Figure 3-17 Dundrum Upper 1D and 2D Model Extents................................................................. 30 Figure 3-18 Dundrum Middle 1D and 2D Model Extents................................................................ 31 Figure 3-19 Dundrum Lower 1D and 2D Model Extents................................................................. 32 Figure 3-20 Example MIKE Flood Input Window............................................................................ 33 Figure 4-1 EVA Plot from Whitechurch NAM Model – Present Day Scenario .................................. 35 Figure 4-2 Flood Outline Comparison – Discharge Scenario ........................................................... 36 Figure 4-3 Difference in Water Levels for Discharge Scenario......................................................... 37 Figure 4-4 Difference in Velocities for Discharge Scenario. ............................................................. 38 Figure 4-5 Flood Outline Comparison – Grid Resolution Scenario................................................... 39 Figure 4-6 Difference in Water Levels for Grid Resolution Scenario. ............................................... 40 Figure 4-7 Difference in Velocities for Grid Resolution Scenario...................................................... 41 Figure 4-8 Varying Floodplain Roughness Data File ........................................................................ 42 Figure 4-9 Difference in Water Levels for Floodplain Roughness Scenario ..................................... 43 Figure 4-10 Difference in Velocities for Floodplain Roughness Scenario ...................................... 44

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Figure 4-11 Difference in Water Levels for Link Weir Roughness Scenario .................................. 45 Figure 4-12 Difference in Velocities for Link Weir Roughness Scenario........................................ 46 Figure 4-13 Flood Outline Comparison – DTM V DSM .................................................................. 47 Figure 4-14 Dodder Upper Flood Outlines...................................................................................... 49 Figure 4-15 Difference in Water Levels for Dodder Upper Future Scenarios................................. 50 Figure 4-16 Difference in Velocities for Dodder Upper Future Scenarios ...................................... 51 Figure 4-17 Dodder Middle Future Scenario Flood Outlines .......................................................... 52 Figure 4-18 Difference in Water Levels for Dodder Middle Future Scenarios................................ 52 Figure 4-19 Difference in Velocities for Dodder Middle Future Scenarios ..................................... 53 Figure 4-20 Dodder Lower Future Scenario Flood Outlines........................................................... 54 Figure 4-21 Difference in Water Levels for Dodder Lower Future Scenarios................................. 55 Figure 4-22 Difference in Velocities for Dodder Lower Future Scenarios ...................................... 56 Figure 5-1 Rainfall-Runoff Sub-Catchment Diagram ........................................................................ 59 Figure 5-2 Example Contour Lines of Equal Probability ................................................................... 61 Figure 5-3 Example Unit Line............................................................................................................ 62 Figure 5-4 Example 1 in 100 Year Joint Probability Diagram ........................................................... 62 Figure 5-5 Rainfall-Runoff Catchment Locations .............................................................................. 65 Figure 6-1 Methodology Sequence ................................................................................................... 83 Figure 6-2 Probability Plot of Extreme Surge Residuals Used in Joint Probability Analysis ............ 84 Figure 6-3 Probability Plot of Extreme Rainfall Used in Joint Probability Analysis........................... 85 Figure 6-4 Joint Probability of Rainfall and Surge Residuals............................................................ 86 Figure 6-5 Discharge V Daily Rainfall ............................................................................................... 87 Figure 6-6 Methodology Sequence ................................................................................................... 92 Figure 7-1 Tallaght NAM Present Day Design Event Hydrographs.................................................. 97 Figure 7-2 Owendoher NAM Present Day Design Event Hydrographs ............................................ 98 Figure 7-3 Whitechurch NAM Present Day Design Event Hydrographs........................................... 98 Figure 7-4 Little Dargle NAM Present Day Design Event Hydrographs ........................................... 99 Figure 7-5 Dundrum NAM Present Day Design Event Hydrographs.............................................. 100 Figure 7-6 Tallaght Urban Present Day Design Event Hydrographs .............................................. 101 Figure 7-7 Owendoher Whitechurch Urban Present Day Design Event Hydrographs ................... 101 Figure 7-8 Little Dargle Urban Present Day Design Event Hydrographs........................................ 102 Figure 7-9 Dundrum Urban 1+2 Present Day Design Event Hydrographs..................................... 103 Figure 7-10 Bohernabreena NAM Present Day Design Event Hydrographs ............................... 105 Figure 7-11 Dodder Main Channel NAM Present Day Design Event Hydrographs ..................... 106 Figure 7-12 Dodder Urban 1 Present Day Design Event Hydrographs........................................ 107 Figure 7-13 Dodder Urban 2 Present Day Design Event Hydrographs........................................ 108 Figure 7-14 Dodder Urban 3+4 Present Day Design Event Hydrographs.................................... 109 Figure 8-1 Example Flood Map....................................................................................................... 110

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LIST OF TABLES Table 2-1 Topographical Survey Summary Table ............................................................................. 4 Table 2-2 CCTV Summary Table....................................................................................................... 5 Table 4-1 Bohernabreena NAM Rainfall-Runoff Model High End Future Scenario Design

Discharges....................................................................................................................... 48 Table 5-1 Example Histogram ......................................................................................................... 60 Table 5-2 Example Probabilities ...................................................................................................... 60 Table 5-3 Example 1 in 100 Year Joint Probability Event Discharges ............................................ 63 Table 5-4 Dodder Main Channel and Tallaght Stream 2 and 5 year Return Period........................ 66 Table 5-5 Dodder Main Channel and Tallaght Stream 10 and 25 year Return Period.................... 66 Table 5-6 Dodder Main Channel and Tallaght Stream 50 and 100 year Return Period.................. 67 Table 5-7 Dodder Main Channel and Tallaght Stream 200 and 1000 year Return Period.............. 67 Table 5-8 Dodder Main Channel and Dodder Urban 1 - 2 and 5 year Return Period ..................... 68 Table 5-9 Dodder Main Channel and Dodder Urban 1 - 10 and 25 year Return Period ................. 68 Table 5-10 Dodder Main Channel and Dodder Urban 1 - 50 and 100 year Return Period ............... 69 Table 5-11 Dodder Main Channel and Dodder Urban 1 - 200 and 1000 year Return Period ........... 69 Table 5-12 Dodder Main Channel and Owendoher - 2 and 5 year Return Period ............................ 70 Table 5-13 Dodder Main Channel and Owendoher - 10 and 25 year Return Period ........................ 71 Table 5-14 Dodder Main Channel and Owendoher - 50 and 100 year Return Period ...................... 71 Table 5-15 Dodder Main Channel and Owendoher - 200 and 1000 year Return Period .................. 72 Table 5-16 Dodder Main Channel and Little Dargle - 2 and 5 year Return Period............................ 73 Table 5-17 Dodder Main Channel and Little Dargle - 10 and 25 year Return Period........................ 73 Table 5-18 Dodder Main Channel and Little Dargle - 50 and 100 year Return Period...................... 74 Table 5-19 Dodder Main Channel and Little Dargle - 200 and 1000 year Return Period.................. 74 Table 5-20 Dodder Main Channel and Dodder Urban 2 - 2 and 5 year Return Period ..................... 75 Table 5-21 Dodder Main Channel and Dodder Urban 2 - 10 and 25 year Return Period ................. 76 Table 5-22 Dodder Main Channel and Dodder Urban 2 - 50 and 100 year Return Period ............... 76 Table 5-23 Dodder Main Channel and Dodder Urban 2 - 200 and 1000 year Return Period ........... 76 Table 5-24 Dodder Main Channel and Dundrum / Slang - 2 and 5 year Return Period.................... 77 Table 5-25 Dodder Main Channel and Dundrum / Slang - 10 and 25 year Return Period................ 77 Table 5-26 Dodder Main Channel and Dundrum / Slang - 50 and 100 year Return Period.............. 78 Table 5-27 Dodder Main Channel and Dundrum / Slang - 200 and 1000 year Return Period.......... 78 Table 5-28 Dodder Main Channel and Dodder Urban 3+4 - 2 and 5 year Return Period ................. 79 Table 5-29 Dodder Main Channel and Dodder Urban 3+4 - 10 and 25 year Return Period ............. 79 Table 5-30 Dodder Main Channel and Dodder Urban 3+4 - 50 and 100 year Return Period ........... 80 Table 5-31 Dodder Main Channel and Dodder Urban 3+4 - 200 and 1000 year Return Period ....... 80 Table 5-32 Owendoher and Whitechurch - 2 and 5 year Return Period ........................................... 81 Table 5-33 Owendoher and Whitechurch - 10 and 25 year Return Period ....................................... 81 Table 5-34 Owendoher and Whitechurch - 50 and 100 year Return Period ..................................... 81 Table 5-35 Owendoher and Whitechurch - 200 and 1000 year Return Period ................................. 82

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Table 6-1 Joint Probability of Rainfall and Surge Residuals............................................................ 86 Table 6-2 Design Event Discharges and Daily Rainfall Totals ........................................................ 88 Table 6-3 Joint Probability Design Event Daily Rainfall Totals and Surge Residual Levels............ 88 Table 6-4 Joint Probability Surge Residual Levels (m).................................................................... 89 Table 6-5 Surge Residuals and Tidal Return Periods ..................................................................... 89 Table 6-6 Design Event Total Coastal Water Levels ....................................................................... 90 Table 6-7 Present Day Scenario Design Discharge Events and Associated Total Coastal Water

Levels............................................................................................................................... 90 Table 6-8 Future SUDS Scenario Design Discharge Events and Associated Total Coastal Water

Levels............................................................................................................................... 91 Table 6-9 Future No SUDS Scenario Design Discharge Events and Associated Total Coastal

Water Levels .................................................................................................................... 91 Table 6-10 Design Event Total Coastal Water Levels ....................................................................... 93 Table 6-11 Design Event Total Coastal Water Levels & Surge Residuals ........................................ 93 Table 6-12 Joint Probability Surge Levels and Daily Rainfall Totals ................................................. 94 Table 6-13 Daily Rainfall Totals and Associated Fluvial Discharges................................................. 94 Table 6-14 Design Event Total Coastal Water Level and Associated Fluvial Discharge .................. 95 Table 7-1 Summary Table of Time to Peak Durations from Historic Record at Waldron’s Bridge

Gauge. ........................................................................................................................... 104 Table 8-1 Flood Locations and Mechanisms from Upper Dodder Model ...................................... 112 Table 8-2 Flood Locations and Mechanisms from Middle Dodder Model ..................................... 113 Table 8-3 Flood Locations and Mechanisms from Lower Dodder Model – Fluvial Scenario ........ 116 Table 8-4 Flood Locations and Mechanisms from Lower Dodder Model – Tidal Scenario ........... 116 Table 8-5 Flood Locations and Mechanisms from Tallaght Stream Model ................................... 117 Table 8-6 Flood Locations and Mechanisms from Owendoher Stream Model.............................. 118 Table 8-7 Flood Locations and Mechanisms from Whitechurch Stream Model ............................ 120 Table 8-8 Flood Locations and Mechanisms from Little Dargle Stream Model ............................. 121 Table 8-9 Flood Locations and Mechanisms from Dundrum / Slang Stream Model ..................... 124

APPENDICES

APPENDIX A Topographical Survey Data

APPENDIX B Future Scenario Dependence Analysis Results

APPENDIX C Future Scenario Hydrographs

APPENDIX D Peak Water Levels and Peak Water Profiles

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EXECUTIVE SUMMARY

The River Dodder has overflowed its banks on numerous occasions, notably during the 1986 ‘Hurricane Charlie’ event and again in 2000 and 2002. Consequently the development of a Catchment Flood Risk Management Plan (CFRMP) for the River Dodder catchment has been identified as a priority project due to existing flood risk. The River Dodder Catchment Flood Risk Assessment and Management Study (CFRAMS), which will inform the River Dodder CFRMP, aims to assess the spatial extent and degree of flood hazard and risk within the Dodder Catchment, examine future pressures that could impact on flood risk, and develop a long-term strategy for managing flood risk that is economically, socially and environmentally sustainable.

The objective of this report is to describe the hydraulic analysis undertaken as part of the River Dodder CFRMP on the River Dodder Main Channel and its five major tributaries (Tallaght, Owendoher, Whitechurch, Dundrum/Slang and Little Dargle Streams). The key purpose of the hydraulic analysis is to produce flood extent maps which will identify flood risk areas for a variety of Annual Exceedance Probability (AEP) events and will be used to inform the flood alleviation optioneering process.

Relevant data was collected for use in the hydraulic analysis which included topographical, meteorological, hydrometric, coastal, historical flooding and climate change information. Using this data individual 1-D and 2-D hydrodynamic models were established in MIKE 11 and MIKE 21, for the River Dodder Main Channel and each of the five major tributaries (Owendoher, Whitechurch, Dundrum/Slang, Little Dargle and Tallaght Stream). These individual MIKE models were then coupled in MIKE Flood producing hydrodynamic models that are fully dynamically linked, exchanging data in each time step of the simulation.

A thorough sensitivity analysis was undertaken on the Whitechurch coupled hydraulic model to ascertain the individual influence of a number of model parameters on the 2-D model results. A second sensitivity analysis was carried out on the High End Future Scenario model inputs for the River Dodder Main Channel hydraulic models.

Examination of the historic hydrological data has shown that flood events on the River Dodder main channel and those on its five major tributaries are relatively independent. To quantify the independence or conversely the dependence of one river or stream with another within the River Dodder catchment a dependence analysis was undertaken. The key objective of the dependence analysis is to derive the design flows for the hydraulic river models used in this CFRAMS.

The River Dodder is influenced by both tidal and fluvial events below the weir at Ballsbridge. While it is relatively easy to derive the return periods for each component separately, under certain circumstances both extreme coastal water levels (storm surge) and extreme discharges in the river can occur. This can result in back water effects potentially giving higher water levels compared to the levels expected from fluvial or coastal events on their own. For the purposes of this study the joint probability total coastal water levels associated with extreme fluvial discharges have been derived along with the joint probability fluvial discharges associated with extreme total coastal water levels. These data combinations will be used as boundary conditions in the lower Dodder hydraulic models to simulate extreme flood conditions.

Design event peak discharges were calculated for fourteen ‘sub-catchment’ rainfall-runoff models for present day and future scenarios in the Hydrological Analysis stage of the River Dodder CFRAMS. To create representative input boundary files for use in the hydraulic models, hydrographs were applied to these peak discharges using the linear reservoir equation.

Flood maps will be created based on the flood outlines produced from the coupled hydraulic models for the River Dodder main channel and its five tributaries. These maps will be contained in a separate Flood Mapping Report.

River Dodder Catchment Flood Risk Assessment and Management Study Hydraulic Analysis Report

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1 INTRODUCTION

1.1 BACKGROUND

The River Dodder has overflowed its banks on numerous occasions, notably during the 1986 ‘Hurricane Charlie’ fluvial event and again in 2002 in conjunction with a tidal event. During these events, particularly the 1986 event, extensive damage was caused in the lower reaches of the River, which flows through south Dublin to the river’s confluence with the Liffey Estuary.

The overriding purpose of the River Dodder Catchment Flood Risk Assessment and Management Study (CFRAMS) is therefore to assess the spatial extent and degree of flood hazard and risk within the Dodder Catchment, examine future pressures that could impact on flood risk, and develop a long-term strategy for managing flood risk that is economically, socially and environmentally sustainable. The outcome of the CFRAMS will be a Catchment Flood Risk Management Plan (CFRMP).

Figure 1-1 Flood Damage from Hurricane Charlie

1.2 OBJECTIVES OF REPORT

The objective of this report is to describe the hydraulic analysis undertaken as part of the River Dodder Catchment Flood Risk Assessment and Management Study project. The hydraulic analysis comprises the collection of relevant data, the construction of 1-D, 2-D and coupled hydraulic models, fluvial and coastal dependence analysis for boundary files, convolution of hydrographs and flood mapping. The key objective of the hydraulic analysis is to produce flood extent maps which will identify flood risk areas for a variety of Annual Exceedance Probability (AEP) events and will be used to inform the flood alleviation optioneering process.


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2 DATA COLLECTION

2.1 TOPOGRAPHICAL SURVEY DATA

Survey requirements for the Dodder River main channel and each of the five major tributaries (Owendoher, Whitechurch, Dundrum/Slang, Little Dargle and Tallaght Stream) were discussed and agreed with the Contracting Authority throughout the survey process. A survey brief including drawings of the Dodder Main Channel and all five tributaries was produced indicating the required cross-section locations. Figure 2-1 is an example drawing which formed part of the survey brief:

Figure 2-1 Typical Survey Brief Drawing

Dublin City Council Surveying and Mapping Section with the assistance of Paul Corrigan & Associates (PCA) Surveyors carried out the river surveys which took approximately 6 months to complete. The survey data package for each river includes the following:

• ASCII files for river cross-sections in two separate formats for import into the hydraulic

modelling software;

• AutoCAD drawing of river centreline (alignment);

• AutoCAD drawing of cross-section locations showing chainages;

• AutoCAD drawing of each cross-section;

• AutoCAD drawing of long-section through centreline of river;

• 3D AutoCAD model of river including structures;

• Photographs taken at each cross-section, structure and outfall ;

• Floor Levels.

Figure 2-2 to Figure 2-4 show examples of some of the survey data received.


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Figure 2-2 Typical ASCII File

Figure 2-3 Typical AutoCAD drawing of river cross-section

A Little Dargle Main Channel 10.000 COORDINATES 1 315815.75 226450.39 FLOW DIRECTION 0 DATUM 0 RADIUS TYPE 2 DIVIDE X-SECTION 0 SECTION ID L-047 INTERPOLATED 0 ANGLE 000 00 00 PROFILE 13 -7.01 86.61 0.03 -4.96 86.54 0.03 -1.19 86.26 0.03<#1> -0.61 85.74 0.03 -0.41 85.59 0.03 -0.00 85.57 0.03 0.00 85.57 0.03 0.10 85.57 0.03<#2> 0.52 85.55 0.03 0.61 85.55 0.03 1.04 85.73 0.03 2.45 86.42 0.03<#4> 2.90 86.45 0.03 ***********************


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Figure 2-4 Typical 3D AutoCAD model

A summary of the topographical survey data received is presented in the Table 2-1.

River Name

Approx. Length of Channel Surveyed

(m)

No. Cross-Sections Surveyed

No. of Bridges

Surveyed

No. of Other Structures Surveyed

No. Photos Taken

Dodder Main Channel 15,670 253 22 15 489

Dundrum / Slang 5,215 83 22 36 184

Little Dargle 4,240 47 9 24 76

Owendoher 4,080 99 26 23 150

Tallaght Stream 5,800 110 18 19 207

Whitechurch 3,355 92 39 16 142

Total 38,360 684 136 133 1248

Table 2-1 Topographical Survey Summary Table

2.1.1 Existing Survey Data

Topographical survey data for two sections of the River Dodder were already in the possession of RPS before starting the River Dodder CFRAMS. These surveys were carried out for two separate flood impact assessments for private developers in 2005 and 2006.


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The first section is between Ballsbridge and Anglesea Road Bridge and includes 21 river cross-sections and details of the 3 bridges along this reach. The second section is between Orwell Weir and the Milltown Viaduct and includes 20 river cross-sections and details of 4 bridges. These sections of the river were not re-surveyed for the River Dodder CFRAMS. RPS provided Dublin City Council Surveying and Mapping Section with the existing survey data so that it could be incorporated into their data.

A digital copy of all topographical survey data collated for use in this study is contained in Appendix A. The extent of existing and newly commissioned topographical survey data is shown in Figure 2-5.

2.2 CCTV SURVEY DATA

A CCTV survey was commissioned to provide details of those stretches of the major tributaries which are culverted / piped and where the topographical survey was unable to provide sufficient detail for use in the hydraulic models. Table 2-2 presents a summary of the culvert / pipe lengths surveyed for each tributary.

Tributary CCTV Survey Length (m)

Dundrum Slang 830

Little Dargle 2130

Owendoher 110

Tallaght 260

Whitechurch 225

Table 2-2 CCTV Summary Table

Insituform Technologies Inc. carried out this survey and provided details of culvert / pipe sizes and lengths which were used in the hydraulic models. The survey also provided the CA and relevant County Councils with details of the condition of these pipes / culverts which can be used to inform any maintenance plans for the areas.

2.3 DIGITAL TERRAIN MODEL DATA

Airborne laser scanning technology was utilised to provide the required digital terrain model data for use in the River Dodder CFRAMS. It is a recent technology for capturing topography data of the earth and offers highly accurate height information.

The Contracting Authority (CA) supplied the following data from a specially commissioned LiDAR (Light Detection and Ranging) survey:

• 2m, 5m and 10m grid Digital Terrain Model (DTM);

• 2m grid Digital Surface Model (DSM);

• Contour Data


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The data was supplied in ASCII, AutoCAD and MapInfo formats. The DSM identifies raised objects on the ground surface while the DTM is a “bare-earth” model. The 2m grid provides a detailed resolution of the topography which is vitally important for an accurate representation of the two dimensional flood flow computation. The extent of initial LiDAR data provided for use in this study is shown in yellow in Figure 2-5.

However, initial hydraulic model results indicated that the extent of the DTM was inadequate in some areas to depict the full river floodplain. For this reason additional DTM data was procured by the CA for the relevant areas and this data was added to the 2-D hydraulic models. The additional DTM areas are shown in pink in Figure 2-5.


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Figure 2-5 Survey Extents


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2.4 HYDROLOGICAL DATA

Details of the hydrological data collated for use in this study are presented in a separate Hydrological Analysis Report. The data includes meteorological, hydrometric, coastal, historic flooding and climate change information.


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3 MODEL CONSTRUCTION

The MIKE Flood modelling system was utilised for the hydraulic analysis component of the River Dodder CFRAMS. MIKE Flood is a software shell comprising the following three components:

• A hydrological model (MIKE 11 Rainfall-Runoff Editor) to describe the hydrological processes in the river catchment. A detailed description of the hydrological modelling carried out for the River Dodder CFRAMS is presented in a separate Hydrological Analysis Report.

• A one-dimensional river model (MIKE 11 HD) to describe the flow in linear rivers and channels.

• A two-dimensional model (MIKE 21 HD) to describe the free surface flow in the river flood plain.

3.1 1-DIMENSIONAL HYDRAULIC MODELS

Individual 1-D hydrodynamic models were established in MIKE 11 for the River Dodder Main Channel and each of the five major tributaries (Owendoher, Whitechurch, Dundrum/Slang, Little Dargle and Tallaght Stream). The MIKE 11 models comprise:

• A Simulation Editor file which contains details of the simulation and provides a link to other MIKE 11 editor files. For the hydraulic models created in this study, the simulation editors have the following input files:

• A Network Editor file containing the location of the river channel and any branches and details of hydraulic structures on the river (weirs, culverts, bridges etc.);

• A Cross-Section Editor file containing all river channel cross-sectional information. This information was taken from the topographical survey data prepared for this study;

• A Boundary Editor file containing all boundary conditions applied to the model. For the models created in this study the boundary editor file normally contains an upstream input discharge hydrograph, a specified downstream water level and some point discharge hydrographs along the length of the river. The downstream water levels are constant values to ensure that peak discharge coincides with peak water level and have been derived from joint probability analysis;

• A Hydrodynamic Editor file containing details of the hydrodynamic parameters adopted in the simulations.

Figure 3-1 presents an example Simulation Editor file showing each of the input files used in the hydraulic models.


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Figure 3-1 Example Simulation Editor File

Nine MIKE 11 Hydrodynamic models were prepared for the River Dodder CFRAMS and each of them is discussed in more detail below:

3.1.1 River Dodder Main Channel

The River Dodder Main Channel 1-D model was split into three separate models to make the simulation run times more manageable. The three models are named Dodder Upper, Dodder Middle and Dodder Lower.

Dodder Upper

The Dodder Upper model stretches from below Bohernabreena Reservoirs to upstream of Firhouse Weir beside the M50 motorway. The total length of the modelled river is 6.1km and includes 66 topographical survey cross-sections. There are 3 weir structures along this length that affect the hydrodynamic characteristics of the river and have been included in the model. The Boundary Editor file in this model contains 5 boundary files:

1. Input discharge hydrograph from Bohernabreena NAM hydrological catchment

Point Source: Chainage 750

2. Input discharge hydrograph from Dodder Main Channel (MC) NAM hydrological catchment



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3. Input discharge hydrograph from Dodder Urban 1 hydrological catchment

Distributed Source: Chainage 750 to 6630

4. Input discharge hydrograph from Tallaght Stream hydraulic model


5. Downstream water level.

Water Level: Chainage 6820

Figure 3-2 presents the 1D model extent for the Dodder Upper as well as identifying the boundary locations. The boundary numbers in the diagram refer to the numbers in the text above.

Figure 3-2 Dodder Upper 1D Model Extent and Boundary Locations


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Dodder Middle

The Dodder Middle model stretches from upstream of Firhouse Weir (end of Dodder Upper model) to downstream of Rathfarnham Road Bridge. The total length of the modelled river is 5km and includes 62 topographical survey cross-sections. There are 2 weir structures along this length that affect the hydrodynamic characteristics of the river and have been included in the model. The Boundary Editor file in this model contains 4 boundary files:

1. Input discharge hydrograph from Dodder Upper hydraulic model


2. Input discharge hydrograph from Dodder Urban 2 hydrological catchment


3. Input discharge hydrograph from Owendoher / Whitechurch hydraulic model




Figure 3-3 presents the 1D model extent for the Dodder Middle as well as identifying the boundary locations. The boundary numbers in the diagram refer to the numbers in the text above.

Figure 3-3 Dodder Middle 1D Model Extent and Boundary Locations


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Dodder Lower – Fluvial Scenario

The Dodder Lower model stretches from Rathfarnham Road Bridge (end of Dodder Middle model) to the confluence with the River Liffey in Ringsend. The total length of the modelled river is 7.9km and includes 83 topographical survey cross-sections. There are 11 weir structures and 11 culvert / bridge structures along this length that affect the hydrodynamic characteristics of the river and have been included in the model. The Boundary Editor file in this model contains 5 boundary files:

1. Input discharge hydrograph from Dodder Middle hydraulic model


2. Input discharge hydrograph from Little Dargle hydraulic model


3. Input discharge hydrograph from Dundrum / Slang hydraulic model


4. Input discharge hydrograph from Dodder Urban 3+4 hydrological catchment




Figure 3-4 presents the 1D model extent for the Dodder Lower Fluvial Scenario as well as identifying the boundary locations. The boundary numbers in the diagram refer to the numbers in the text above.


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Figure 3-4 Dodder Lower – Fluvial Scenario 1D Model Extent and Boundary Locations

Dodder Lower – Tidal Scenario

The Dodder Lower model, as described in the previous section, is also used to model Tidal Scenario events. The Boundary Editor file in this model contains 2 boundary files:

1. Input discharge as a constant value




Figure 3-5 presents the 1D model extent for the Dodder Lower Tidal Scenario as well as identifying the boundary locations. The boundary numbers in the diagram refer to the numbers in the text above.


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Figure 3-5 Dodder Lower – Tidal Scenario 1D Model Extent and Boundary Locations

3.1.2 Tallaght Stream

The Tallaght Stream model stretches from Jobstown Road in Jobstown to the confluence with the River Dodder in Firhouse. The total length of the modelled stream is 4.7km and includes 95 topographical survey cross-sections. There are 27 weir structures and 11 culvert / bridge structures along this length that affect the hydrodynamic characteristics of the river and have been included in the model. A tributary branch of the stream is also modelled which is 0.6km long and includes 7 topographical survey cross-sections. The branch joins the main channel downstream of Whitestown Way Bridge. The Tallaght Stream is a small watercourse which increases in dimensions as it flows downstream toward the River Dodder. A number of significant inflows discharge to the stream along its length and for this reason there are a large number of boundary files associated with the model. The Boundary Editor file in this model contains 9 boundary files as follows:

1. Input discharge hydrograph from Tallaght NAM hydrological catchment – Split in 5

Point Source: Chainage 0 (Main Channel)


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2. Input discharge hydrograph from Tallaght NAM hydrological catchment – Split in 3

Point Source: Chainage 0 (Side Channel)

3. Input discharge hydrograph from Tallaght NAM hydrological catchment – Remainder


4. Input discharge hydrograph from Tallaght Urban hydrological catchment – Split in 4

Distributed Source: Chainage 10 to 4720 (Main Channel)

5. Input discharge hydrograph from Tallaght Urban 1 hydrological catchment










Figure 3-6 presents the 1D model extent for the Tallaght Stream as well as identifying the boundary locations. The boundary numbers in the diagram refer to the numbers in the text above.

Figure 3-6 Tallaght Stream 1D Model Extent and Boundary Locations


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3.1.3 Owendoher Stream

The Owendoher Stream model stretches from the M50 bridge in Edmonstown to the confluence with the River Dodder in Bushy Park, Rathfarnham. The total length of the modelled river is 4.1km and includes 118 topographical survey cross-sections. There are 10 weir and 16 no. culvert structures along this length that affect the hydrodynamic characteristics of the river and have been included in the model. The Boundary Editor file in this model contains 4 boundary files:

1. Input discharge hydrograph from Owendoher NAM hydrological catchments


2. Input discharge hydrograph from Whitechurch hydraulic model


3. Input discharge hydrograph from Owendoher Whitechurch Urban hydrological catchment


4. Downstream Water Level


Figure 3-7 presents the 1D model extent for the Owendoher Stream as well as identifying the boundary locations. The boundary numbers in the diagram refer to the numbers in the text above.


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Figure 3-7 Owendoher Stream 1D Model Extent and Boundary Locations

3.1.4 Whitechurch Stream

The Whitechurch Stream model stretches from the M50 bridge in Kilmashogue to the confluence with the Owendoher Stream in Willbrook. The total length of the modelled river is 3.4km and includes 112 topographical survey cross-sections. There are 4 weir structures and 6 culvert / bridge structures along this length that affect the hydrodynamic characteristics of the river and have been included in the model. The Boundary Editor file in this model contains 3 boundary files:

1. Input discharge hydrograph from Whitechurch NAM hydrological catchment – Split in 2


2. Input discharge hydrograph from Whitechurch NAM hydrological catchment – Split in 2



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3. Input discharge hydrograph from Owendoher Whitechurch Urban hydrological catchment




Figure 3-8 presents the 1D model extent for the Whitechurch Stream as well as identifying the boundary locations. The boundary numbers in the diagram refer to the numbers in the text above.

Figure 3-8 Whitechurch Stream 1D Model Extent and Boundary Locations

3.1.5 Little Dargle Stream

The Little Dargle Stream model stretches from Marley Park to the confluence with the River Dodder in Churchtown. The total length of the modelled river is 4.2km and includes 35 topographical survey cross-sections. There are 3 weir structures and 5 culvert / bridge structures along this length that affect the hydrodynamic characteristics of the river and have been included in the model. The Boundary Editor file in this model contains 3 boundary files:


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1. Input discharge hydrograph from Little Dargle NAM hydrological catchment (83.33%)


2. Input discharge hydrograph from Little Dargle NAM hydrological catchment (16.67%)


3. Input discharge hydrograph from Little Dargle Urban hydrological catchment




Figure 3-9 presents the 1D model extent for the Little Dargle Stream as well as identifying the boundary locations. The boundary numbers in the diagram refer to the numbers in the text above.

Figure 3-9 Little Dargle Stream 1D Model Extent and Boundary Locations


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3.1.6 Dundrum / Slang Stream

The Dundrum / Slang model stretches from Wesley College in Ballinteer to the confluence with the River Dodder in Milltown. The total length of the modelled river is 4.6km and includes 70 topographical survey cross-sections. There are 3 weir structures and 7 culvert / bridge structures along this length that affect the hydrodynamic characteristics of the river and have been included in the model. A tributary branch of the stream is also modelled which is 0.8km long and includes 22 topographical survey cross-sections. There is 1 weir structure and 2 culvert / bridge structures along this tributary branch that have been included in the model. The branch joins the main channel at Ballinteer Road bridge in Dundrum. The Boundary Editor file in this model contains 4 boundary files:

1. Input discharge hydrograph from Dundrum NAM hydrological catchment (Portion)


2. Input discharge hydrograph from Dundrum NAM hydrological catchment (Portion)

Point Source: Chainage 0 (Tributary)

3. Input discharge hydrograph from Dundrum Urban 1+2 hydrological catchment




Figure 3-10 presents the 1D model extent for the Dundrum / Slang Stream as well as identifying the boundary locations. The boundary numbers in the diagram refer to the numbers in the text above.


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Figure 3-10 Dundrum / Slang Stream 1D Model Extent and Boundary Locations

3.2 2-DIMENSIONAL HYDRAULIC MODELS

Individual 2-D hydrodynamic models were established in MIKE 21 for the River Dodder Main Channel and four of the major tributaries (Owendoher, Whitechurch, Dundrum/Slang and Tallaght Stream). A 2-D model was not established for the Little Dargle as little flooding is expected on this tributary. The significant inputs to the MIKE 21 models are as follows:

• Bathymetry

The bathymetry files used in the MIKE 21 models are based on the Digital Terrain Model (DTM) data supplied for this study. This data provides details of the river floodplains and facilitates modelling of out of bank flow. The bathymetry files are composed of square cells of a specified size which dictate the resolution of the output flood outlines. The bathymetry files for some models have been trimmed to an expected floodable area to improve run times.


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The cells describing the topography of the river beds have been blocked out to avoid double counting the flow in the streams.

• Flooding / Drying Depths

The MIKE 21 models provide a facility for specifying the depth at which the model cells are identified as wet or dry.

• Floodplain Resistance

The resistance or roughness of the floodplain surface can be specified in MIKE 21 as either a Chezy Number or a Manning’s Number. For the purposes of this study a Manning’s number (M) has been adopted. Manning’s ‘M’ is the inverse of the commonly used Manning’s ‘n’ number.

Ten MIKE 21 Hydrodynamic models were prepared for the River Dodder CFRAMS and each of them is discussed in more detail below:

3.2.1 River Dodder Main Channel

Three separate 2-D models were created for the River Dodder Main Channel and were named Dodder Upper, Dodder Middle and Dodder Lower as per the 1-D model set-up.

Dodder Upper

The bathymetry file used in the Dodder Upper 2D model is approximately 5.8 x 0.95 km in size with cell dimensions of 4x4 m for the higher frequency events (2, 5, 10, 25, 50 and 100 year) and 6x6 m for low frequency events (200 and 1000 year). The reason for the change in cell size relates to the stability of the MIKE 21 model when there is a large amount of flooding. The flooding and drying depths are set to 20mm and 10mm respectively and the floodplain resistance has a Manning’s Number of 32. Figure 3-11 presents the 1D and 2D model extents for the Dodder Upper model.


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Figure 3-11 Dodder Upper 1D and 2D Model Extents

Dodder Middle

The bathymetry file used in the Dodder Middle 2D model is approximately 4.2 x 1.2 km in size with cell dimensions of 4x4 m for the higher frequency events (2, 5, 10, 25, 50 and 100 year) and 6x6 m for low frequency events (200 and 1000 year). The reason for the change in cell size relates to the stability of the MIKE 21 model when there is a large amount of flooding. The flooding and drying depths are set to 20mm and 10mm respectively and the floodplain resistance has a Manning’s Number of 32. Figure 3-12 presents the 1D and 2D model extents for the Dodder Middle model.


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Figure 3-12 Dodder Middle 1D and 2D Model Extents

Dodder Lower – Fluvial Scenario

The bathymetry file used in the Dodder Lower 2D model is approximately 15.9 km2 in size with cell dimensions of 4x4 m for the higher frequency events (2, 5, 10, 25 and 50 year) and 6x6 m for low frequency events (100, 200 and 1000 year). The reason for the change in cell size relates to the stability of the MIKE 21 model when there is a large amount of flooding. The flooding and drying depths are set to 20mm and 10mm respectively and the floodplain resistance has a Manning’s Number of 32. Figure 3-13 presents the 1D and 2D model extents for the Dodder Lower model.


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Figure 3-13 Dodder Lower 1D and 2D Model Extents

Dodder Lower – Tidal Scenario

The 2-D model used for the Dodder Lower – Tidal Scenario is the same as that used for the Dodder Lower – Fluvial Scenario


The bathymetry file used in the Tallaght Stream 2D model is approximately 4.2 x 2.0 km in size with cell dimensions of 2x2m for the higher frequency events (2, 5, 10, 25, 50, 100 and 200 year) and 4x4m for low frequency events (1000 year). The reason for the change in cell size relates to the stability of the MIKE 21 model when there is a large amount of flooding. The flooding and drying depths are set to


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20mm and 10mm respectively and the floodplain resistance has a Manning’s Number of 32. Figure 3-14 presents the 1D and 2D model extents for the Tallaght Stream model.

Figure 3-14 Tallaght Stream 1D and 2D Model Extents


The bathymetry file used in the Owendoher Stream 2D model is approximately 0.6 x 3.2 km in size with cell dimensions of 2x2m for all return period events (2, 5, 10, 25, 50, 100, 200 and 1000 year). The flooding and drying depths are set to 30mm and 20mm respectively and the floodplain resistance has a Manning’s Number of 32. The flooding and drying depths differ from those in the other 2-D models for stability reasons. Figure 3-15 presents the 1D and 2D model extents for the Owendoher Stream model.


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Figure 3-15 Owendoher Stream 1D and 2D Model Extents


The bathymetry file used in the Whitechurch Stream 2D model is approximately 0.8 x 3.0 km in size with cell dimensions of 2x2m for all return period events (2, 5, 10, 25, 50, 100, 200 and 1000 year). The flooding and drying depths are set to 20mm and 10mm respectively and the floodplain resistance has a Manning’s Number of 32. Figure 3-16 presents the 1D and 2D model extents for the Whitechurch Stream model.


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Figure 3-16 Whitechurch Stream 1D and 2D Model Extents


The background DTM used in the Dundrum / Slang Stream 2-D hydraulic model has been supplied as three separate files which necessitate the production of 3 separate 2-D models. The models are referred to as Dundrum Upper, Dundrum Middle and Dundrum Lower.

Dundrum Upper

The bathymetry file used in the Dundrum Upper 2D model is approximately 1.2 x 1.0 km in size cell dimensions of 2x2m for the higher frequency events (2, 5, 10, 25, 50, 100 and 200 year) and 4x4m for low frequency events (1000 year).. The flooding and drying depths are set to 20mm and 10mm respectively and the floodplain resistance has a Manning’s Number of 32.


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Figure 3-17 presents the 1D and 2D model extents for the Dundrum Upper model.

Figure 3-17 Dundrum Upper 1D and 2D Model Extents

Dundrum Middle

The bathymetry file used in the Dundrum Middle 2D model is approximately 0.5 x 1.6 km in size with cell dimensions of 2x2m for all return period events (2, 5, 10, 25, 50, 100, 200 and 1000 year). The flooding and drying depths are set to 20mm and 10mm respectively and the floodplain resistance has a Manning’s Number of 32. Figure 3-18 presents the 1D and 2D model extents for the Dundrum Middle model.


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Figure 3-18 Dundrum Middle 1D and 2D Model Extents

Dundrum Lower

The bathymetry file used in the Dundrum Lower 2D model is approximately 0.5 x 1.8 km in size with cell dimensions of 2x2m for all return period events (2, 5, 10, 25, 50, 100, 200 and 1000 year). The flooding and drying depths are set to 20mm and 10mm respectively and the floodplain resistance has a Manning’s Number of 32. Figure 3-19 presents the 1D and 2D model extents for the Dundrum Lower model.


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Figure 3-19 Dundrum Lower 1D and 2D Model Extents

3.3 COUPLED HYDRAULIC MODELS

Individual MIKE Flood models were established for the River Dodder Main Channel and four of the major tributaries (Owendoher, Whitechurch, Dundrum/Slang and Tallaght Stream). These MIKE Flood models couple the MIKE 11 (1-D) and MIKE 21 (2-D) models producing hydrodynamic models that are fully dynamically linked, exchanging data in each time step of the simulations.

The links between the 1D/ 2D model were established as lateral links for the entire length of each model. Once the water level in the MIKE 11 model exceeds the bank height it spills into the MIKE 21 model along these lateral link boundaries. Links were established for the left bank and the right bank separately, to take account of the different elevations of each bank. Sections that do not allow overspill into the flood plain, such as walled bridges and culverts, were not coupled to the 2D model. There is


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an option in the MIKE couple models to define the source of the link geometry and for the purposes of this study the geometry is taken as the highest of the MIKE 11 bank markers and MIKE 21 cells. The lateral links are modelled as weir structures and the depth of water at the crest at which spill occurs is set at 0.1m for all models.

Figure 3-20 presents the input window from an example MIKE Flood couple file. The MIKE 11 and MIKE 21 input files are shown at the top of the screen and the bathymetry is displayed in the lower right hand side. The links are listed in the centre of the screen and include information on the river chainage and the number of cells incorporated.

Figure 3-20 Example MIKE Flood Input Window

3.4 MODEL CALIBRATION

The data available for the calibration of the coupled hydraulic models produced for each of the rivers was limited due to the absence of significant numbers of gauging sites. The three gauging stations present in the Dodder catchment were simulated as part of the rating curve extrapolation. Thus it would be expected that a good correlation between observed levels and simulated elevations should be achieved at these locations.

The input data to the hydraulic models was developed from calibrated hydrological models of three gauge catchments (Waldron’s Bridge, Willbrook Road and Frankfort) as discussed in Sections 4.2 and 5.2 of the Hydrological Analysis Report. These hydrological models were calibrated against recent recorded flow data to produce models which simulate the rainfall-runoff response of the catchments under current development conditions.

Extensive calibration of the lower return period flood outlines generated by the hydraulic models was undertaken using historic data and observations made by the area engineers from Dublin City Council, South Dublin County Council and Dun Laoghaire Rathdown County Council. A key objective was to calibrate the flood extents with previous events such as Hurricane Charlie and in the case of the tidal


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model, the 2002 coastal flooding event. If the flooded extent differed from the observations additional analysis was undertaken to identify the cause. This has not always lead to a revision of the modelling, as often the modelling has helped to understand the flood mechanism which in turn could be verified by the area engineers. Two recent events, the flooding along the Whitechurch in 2007 & 2008 and flooding of the main Dodder with low return periods were used to verify the model and in general a good correlation was found.

One significant difference between the flood extent simulated and observed is that walls and small changes in topography with a horizontal extent of less than 2m are not captured in the model unless these are recognised flood defences alongside the river. The key reason is that if these are not recognised as flood defences they could be removed resulting in changes to the flooded extent. However the properties protected by these walls are still at flood risk. Thus the furthest possible flood extent was derived in the modelling to identify all properties at risk.

In addition a number of simulations were carried out to identify the sensitivity of the results to certain parameters either fixed in the model of the chosen flows. While this did not provide any additional data for the calibration, it highlighted the importance of different parameters to the results of the modelling. The outcome of this analysis is discussed in the following section.


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4 SENSITIVITY ANALYSES

4.1 COUPLED HYDRAULIC MODEL

A sensitivity analysis was undertaken on a coupled hydraulic model to ascertain the individual influence of a number of model parameters on the 2-D model results. The Whitechurch Stream model with a 1% AEP event (Present Day Scenario) and grid cell size of 4mx4m was chosen for this exercise. The Whitechurch model set-up is similar to all the coupled hydraulic models created for this study and is considered a ‘Standard Case’. The model parameters which will be analysed are the discharge, the grid resolution, the floodplain roughness and the link weir roughness. Each parameter will be independently altered in the model and any effect on model results examined. In particular any changes to flood outline, water level and velocity will be inspected and for all analyses the Sensitivity Scenario results will be deducted from the Standard Case results. By this method, a positive change in water level or velocity indicates higher values in the Standard Case and a negative change indicates lower values in the Standard Case.

4.1.1 Discharge

As part of the Hydrological Analysis Report prepared for the River Dodder CFRAMS, design event peak discharges were calculated for the Whitechurch Stream model for a variety of different events. To calculate these discharges, an Extreme Value Analysis (EVA) was undertaken on discharge files produced using a NAM hydrological model. The results of the Present Day Scenario EVA are presented in graphical format as Figure 4-1.

Figure 4-1 EVA Plot from Whitechurch NAM Model – Present Day Scenario


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From Figure 4-1, the Present Day 100 Year Return Period (1% AEP) peak discharge can be interpreted as 27m3/s and this flow has been used in the Standard Case coupled model to produce a 1% AEP event flood outline. The dashed lines on the graph are confidence limits of 68%. The Lower confidence limit flow from this graph is approximately 21m3/s (78%) and the upper confidence limit flow is approximately 31m3/s (115%).

For this purposes of this sensitivity analysis the upper confidence limit flow of 31m3/s has been used in the Sensitivity Scenario coupled model and the effect on the model results examined.

Figure 4-2 shows the flood outlines produced from the Standard Case model (Peak flow = 27m3/s) and the Sensitivity Scenario model (Peak flow = 31m3/s).

Figure 4-2 Flood Outline Comparison – Discharge Scenario

It can be seen from Figure 4-2 that the Sensitivity Scenario flood outline is slightly larger than that produced by the Standard Case model. Further examination of the data reveals that the flood outline produced from the Sensitivity Scenario flow is approximately 181,600m2 in size and that produced from the Standard Case flow is approximately 162,400m2, a difference of approximately +12%. The


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Sensitivity Scenario flood outline encompasses 10 more properties than the flood outline produced from the Standard Case flow.

The water level and velocity outputs were also examined as part of this analysis and the results are presented in Figure 4-3 and Figure 4-4.

Figure 4-3 Difference in Water Levels for Discharge Scenario.

Figure 4-3 has been created by deducting the water levels in the Sensitivity Scenario flood outline from those produced by the Standard Case model. The average increase in water level in the Sensitivity Scenario results is approximately 50mm or +16% of the average water level in the Standard Case results.


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Figure 4-4 Difference in Velocities for Discharge Scenario.

Figure 4-4 has been created by deducting the velocities in the Sensitivity Scenario flood outline from those produced by the Standard Case model. The velocity appears to be lower in most areas for the Standard Case except for a few small pockets where the results are showing an increase in velocity. The average change in velocity value is approximately 0.1m3/s which is an increase of approximately 17% on the average velocity value in the Standard Case flood outline.

In summary, an increase in peak flow from 27m3/s to 31m3/s has some impact on the flood outline, water levels and the floodplain velocities. The flood outline area is increased by approximately 12%, the water levels are increased by approximately 16% and the floodplain velocities are increased by approximately 17%.

4.1.2 2-D Model Grid Resolution

The bathymetry files used in the 2-D hydrodynamic models are composed of square cells of a specified size which dictate the resolution of the output flood outlines. For the purposes of this


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sensitivity analysis, the flood outline from the Sensitivity Scenario coupled model has been produced using a grid with a cell size of 2mx2m and is compared with the Standard Case which uses a grid with a cell size of 4mx4m.

Figure 4-5 shows the Standard Case flood outline (4mx4m grid) and the Sensitivity Scenario flood outline (2mx2m grid).

Figure 4-5 Flood Outline Comparison – Grid Resolution Scenario

It can be seen from Figure 4-5 that the Standard Case flood outline differs from that produced using the Sensitivity Scenario model to a small extent in a number of locations. The flood outline produced from the Sensitivity Scenario model is approximately 173,350m2 in size and that produced from the Standard Case model is approximately 162,400m2, a difference of approximately +7%. The number of properties flooded in each scenario is virtually identical.

To ascertain the difference in flood depths for the two scenarios, the water level from each cell in the flood outline produced using the Sensitivity Scenario model was deducted from that produced using the Standard Case model and a portion of the results are shown in Figure 4-6


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Figure 4-6 Difference in Water Levels for Grid Resolution Scenario.

It can be seen from Figure 4-6, that the majority of water levels from the Standard Case flood outline are lower than those produced using the Sensitivity Scenario model. The average increase in water level in the Sensitivity Scenario flood outline is approximately 50mm or +16% of the average water level in the Standard Case results.

To ascertain the difference in velocities for the two scenarios, the velocity from each cell in the Sensitivity Scenario flood outline was deducted from that produced using the Standard Case model and a portion of the results are shown in Figure 4-7.


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Figure 4-7 Difference in Velocities for Grid Resolution Scenario.

It can be seen from Figure 4-7, that the majority of velocity values from the Standard Case flood outline are lower than those produced using the Sensitivity Scenario model. The average increase in velocity in the Sensitivity Scenario results is approximately 0.11m3/s which is an increase of approximately 20% on the average velocity in the Standard Case.

In summary, changing the grid cell size from 4x4m to 2mx2m has no material impact on the flood outline. However, the change has some impact on the water levels and floodplain velocities with average increases of approximately 16% and 20% respectively.

4.1.3 Floodplain Resistance

The resistance or roughness of the floodplain surface in the Standard Case 2-D model has been specified as a uniform roughness over the entire floodplain with a Manning’s M of 32. Manning’s M is the inverse of the more commonly used Manning’s ‘n’. A Manning’s M of 32 equates to a Manning’s ‘n’ of 0.0313 which is considered appropriate for a grassed floodplain.


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For the purposes of this sensitivity analysis, a data file has been produced where each bathymetry grid point has an associated roughness value depending on whether it is located in a road or a property or a greenfield site. A Manning’s M of 52 (Manning’s ‘n’ = 0.019) has been applied to the roads which is a low resistance value and is considered appropriate for concrete or paved surfaces. A Manning’s M of 20 (Manning’s ‘n’ = 0.05) has been applied to properties which is a high resistance value and is considered appropriate for a floodplain with tree stumps and brush or a mountain stream with large boulders. A Manning’s M of 32 (Manning’s ‘n’ = 0.0313) has been applied to all other locations. Figure 4-8 shows a portion of the varying floodplain roughness data file prepared for this analysis. The numbers in the legend refer to Manning’s M values.

Figure 4-8 Varying Floodplain Roughness Data File

The Sensitivity Scenario coupled model was run with the varying floodplain roughness data file and compared against the Standard Case model. The results indicated that the flood outline produced using the Sensitivity Scenario model and that produced using the Standard Case model are virtually identical in all areas. The water level and velocity outputs were further examined and the results presented in Figure 4-9 and Figure 4-10.


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Figure 4-9 Difference in Water Levels for Floodplain Roughness Scenario

Figure 4-9 has been created by deducting the water levels from the Sensitivity Scenario flood outline from the water levels produced using the Standard Case model. As expected, this figure shows that the Standard Case flood outline produces larger water levels along some of the roads and smaller water levels at the site of some properties.


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Figure 4-10 Difference in Velocities for Floodplain Roughness Scenario

Figure 4-10 was produced by deducting the velocities in the Sensitivity Scenario floodplain from the velocities produced using the Standard Case model. This figure shows that the Standard Case flood outline produces lower velocities along some of the roads and higher velocities at the site of some properties.

In summary, the flood outline produced using the Sensitivity Scenario model is virtually identical to that produced using Standard Case model. However the water levels and velocities are altered to a small extent.

4.1.4 Link Weir Roughness

Lateral links have been established between the 1-D and 2-D elements of all of the coupled hydrodynamic models produced for the River Dodder CFRAMS. These links facilitate the movement of water from the 1-D river channel model to the 2-D floodplain model and they are modelled as weir structures. As such, the MIKE Flood model requires the user to define weir parameters for each link including a roughness value defined in terms of Manning’s ‘n’.


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The Standard Case coupled model created for this study has a lateral link weir roughness value of Manning’s ‘n’ = 0.05 which is a resistance value considered appropriate for heavily vegetated embankments. For the purposes of this analysis the Sensitivity Scenario model link weir roughness value has been lowered to Manning’s ‘n’ = 0.015 which is a resistance value considered appropriate for concrete walls. The result of this analysis indicates that the Standard Case flood outline and that produced using the Sensitivity Scenario model are virtually identical in all areas. The water level and velocity outputs were further examined and the results presented in Figure 4-11 and Figure 4-12.

Figure 4-11 Difference in Water Levels for Link Weir Roughness Scenario Figure 4-11 was produced by deducting the water levels in the Sensitivity Scenario floodplain from the water levels produced using the Standard Case model. This figure shows that any change in water level is barely perceptible for this scenario.


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Figure 4-12 Difference in Velocities for Link Weir Roughness Scenario

Figure 4-12 was produced by deducting the velocities in the Sensitivity Scenario floodplain from the velocities produced using the Standard Case model. This figure shows that there are some small localised changes in velocity, but they are deemed to have no material effect on the model results.

In summary, altering the lateral link weir roughness value from Manning’s ‘n’ = 0.05 to Manning’s ‘n’ = 0.015 does not appear to have any material effect on the model results.

4.1.5 Digital Surface Model (DSM) V Digital Terrain Model (DTM)

The bathymetry file used in the 2-D hydrodynamic models has been generated from a digital terrain model (DTM). A DTM describes the topography of the landscape without any structures, trees etc and overland flood waters are therefore allowed to flow unimpeded across the floodplain. For the purposes of this sensitivity analysis the Whitechurch Stream model was run with a bathymetry file developed from a digital surface model (DSM). A DSM describes the topography of the landscape including all raised surfaces such as building structures, tree etc and therefore contains more obstacles to the flow of overland flood waters. The flood outline generated using the DSM and the Standard Case flood outline are presented in Figure 4-13.


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Figure 4-13 Flood Outline Comparison – DTM V DSM

It can be seen from Figure 4-13 that the Standard Case flood outline differs considerably from that produced using the DSM. The flood outline produced using the DSM is approximately 38,150m2 in size and that produced from the Standard Case model is approximately 162,400m2, a difference of approximately -76.5%.

The smaller flood outline produced using the DSM can be attributed to obstacles in the landscape impeding the flow of overland flood waters. The DSM assumes all obstacles to be solid e.g. tree canopies or building structures, which don’t allow any flow of water through them. This of course is an incorrect assumption as in reality water will often flow through buildings / hedgerows or break through walls etc, in extreme flood events. In addition the flood water storage offered by building structures is not accounted for in the DSM. A DTM has been used in the 2-D hydrodynamic models as it provides a conservative flood outline and assumes free flow of overland flood waters.


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4.2 HIGH END FUTURE SCENARIO

As part of the Hydrological Analysis element of the River Dodder CFRAMS, a High End Future Scenario rainfall data-set was produced for the Bohernabreena NAM rainfall-runoff model. This data-set adopted the maximum predicted changes in precipitation for each calendar month from three separate climate change models as discussed in Section 3.5 and Section 6.2.3 of the Hydrological Analysis Report.

The High End Future Scenario rainfall data-set was run through the Bohernabreena rainfall-runoff model and a simulated discharge file produced. An extreme value analysis (EVA) was carried out on this discharge file and design discharges of known return period calculated. Table 4-1 presents the High End Future Scenario design discharges.

Return Period (Years)

Discharge (m3/s)

2 54.53

5 69.20

10 80.73

25 97.87

50 112.78

100 129.75

200 149.12

1000 205.57

Table 4-1 Bohernabreena NAM Rainfall-Runoff Model High End Future Scenario Design Discharges

For the purposes of this sensitivity analysis the 1 in 100 Return Period event will be further examined.

As shown in Table 4-1, the High End Future Scenario 1 in 100 Year Return Period discharge from the Bohernabreena NAM rainfall-runoff model is 129.75m3/s. This discharge is approximately 13.2% greater than the 1 in 100 year discharge of 114.63m3/s produced by the Average Future Scenario (Future No SUDS) Bohernabreena NAM model (see Table 6.8 in the Hydrological Analysis Report). This percentage increase in discharge of 13.2% was applied to all flows contributing to the Dodder Upper, Dodder Middle and Dodder Lower hydraulic models and the resulting flood outlines analysed.

For this sensitivity analysis the flood outline, water level and velocity will be examined for each model and in each case the High End Future Scenario results will be deducted from the Average Future Scenario results. By this method, a positive change in water level or velocity indicates higher values in the Average Future Scenario and a negative change indicates lower values in the Average Future Scenario.

4.2.1 Dodder Upper

For the 1 in 100 year return period Dodder Upper High End Future Scenario hydraulic model the Bohernabreena NAM flow of 129.75m3/s was applied as a hydrograph and all other Average Future Scenario input flows to the model were increased by 13.2%. The flood outline produced by this model


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has an area approximately 17% larger than the flood outline produced using the Average Future Scenario (Future No SUDS) input flows. Figure 4-14 presents a portion of the flood outlines. It can be noted that the flood outlines differ to a relatively small degree due to the fact that the river valley is quite steep through this area.

Figure 4-14 Dodder Upper Flood Outlines

The water level and velocity outputs were further examined and the results presented in Figure 4-15 and Figure 4-16.


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Figure 4-15 Difference in Water Levels for Dodder Upper Future Scenarios

Figure 4-15 was produced by deducting the water levels in the High End Future Scenario floodplain from the water levels produced using the Average Future Scenario model. This figure shows that any change in water level is barely perceptible. The statistics from the model outputs indicate that the difference in mean water depth between the High End and Average Future Scenarios is less than 1%.

To ascertain the difference in velocities for the two scenarios, the velocity from each cell in the High End Future scenario flood outline was deducted from that produced using the Average Future Scenario model and a portion of the results are shown in Figure 4-16.


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Figure 4-16 Difference in Velocities for Dodder Upper Future Scenarios

This figure indicates that there are some minor changes to flow velocity both positive and negative. The statistics from the model results indicate that the mean velocity in the High End Future Scenario flood outline is approximately 2% less than that in the Average Future Scenario outline.

4.2.2 Dodder Middle

The output hydrograph from the Dodder Upper High End Future Scenario 1 in 100 year hydraulic model was applied as an input flow to the Dodder Middle High End Future Scenario hydraulic model. All other Average Future Scenario input flows to the model were increased by 13.2%. The flood outline produced by the Dodder Middle High End Future Scenario hydraulic model is approximately 28% larger than the flood outline produced using the Dodder Middle Average Future Scenario hydraulic model. Figure 4-17 presents a portion of the flood outlines.


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Figure 4-17 Dodder Middle Future Scenario Flood Outlines


Figure 4-18 Difference in Water Levels for Dodder Middle Future Scenarios


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Figure 4-18 was produced by deducting the water levels in the High End Future Scenario floodplain from the water levels produced using the Average Future Scenario model. This figure shows that any change in water level is minimal. The statistics from the model outputs indicate that the difference in mean water depth between the High End and Average Future Scenarios is approximately 4%.


Figure 4-19 Difference in Velocities for Dodder Middle Future Scenarios

This figure indicates that there are some minor changes to flow velocity both positive and negative. The statistics from the model results indicate that the mean velocity in the High End Future Scenario is approximately 9% greater than that in the Average Future Scenario.

4.2.3 Dodder Lower

The output hydrograph from the Dodder Middle High End Future Scenario 1 in 100 year hydraulic model was applied as an input flow to the Dodder Lower High End Future Scenario hydraulic model. All other Average Future Scenario input flows to the model were increased by 13.2%. The High End Future Scenario tide level was applied to the downstream boundary of this model (see Section 3.5.2 of the Hydrological Analysis Report for further details). The High End Future Scenario tide level is +800mm over Present Day tidal conditions and +300mm over the Average Future Scenario tidal boundary. For this 1 in 100 year return period event a tide level of 3.36mOD has been applied for the High End Future Scenario which equates to the Average Future (No SUDS) Scenario tide level of 3.06mOD +300mm (See Section 6.1.5 of this report). The flood outline produced by the Dodder Lower High End Future Scenario hydraulic model is approximately 67% larger than the flood outline produced using the Dodder Lower Average Future Scenario hydraulic model. The large increase is


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flood outline area can be attributed to the flat topography in this area. Figure 4-20 presents a portion of the flood outlines.

Figure 4-20 Dodder Lower Future Scenario Flood Outlines



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Figure 4-21 Difference in Water Levels for Dodder Lower Future Scenarios

Figure 4-21 was produced by deducting the water levels in the High End Future Scenario floodplain from the water levels produced using the Average Future Scenario model. This figure shows that there are some relatively large changes in water level. The statistics from the model outputs indicate that the difference in mean water depth between the High End and Average Future Scenarios is approximately 167%.



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Figure 4-22 Difference in Velocities for Dodder Lower Future Scenarios

This figure indicates that there are some significant changes to flow velocity both positive and negative. The statistics from the model results indicate that the mean velocity in the High End Future Scenario is approximately 23% (0.1m/s) greater than that in the Average Future Scenario.


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4.3 SUMMARY AND CONCLUSIONS

A sensitivity analysis was undertaken on the discharge, the grid resolution, the floodplain roughness and the link weir roughness parameters of the Whitechurch Stream 1% AEP coupled model. The results of this analysis can be summarised as follows:

• The peak flow was increased from 27m3/s to 31m3/s which corresponds to the 68% upper confidence limit from the discharge statistical analysis. This increase in peak flow had some impact on the flood outline, water levels and the floodplain velocities. The flood outline area is increased by approximately 12%, the water levels are increased by approximately 16% and the floodplain velocities are increased by approximately 17%.

• The bathymetry grid cell size was changed from 4mx4m to 2mx2m and this had no material impact on the flood outline. However, the change has some impact on the water levels and floodplain velocities with average increases of approximately 16% and 20% respectively. A smaller grid cell size is often favoured for accuracy, but can result in vastly increased computational times. A balanced approach has been taken with the River Dodder CFRAMS hydraulic models and for the Standard Case model a grid cell size of 4mx4m has been adopted.

• The floodplain roughness was altered to take account of individual roads and properties and this had a small impact on water levels and floodplain velocities. It would take a significant amount of time to produce roughness data files for the whole River Dodder catchment and from this exercise it is felt that the small changes in water depth and velocity accuracy would not justify this in particular compared to some of the other uncertainties involved

• The lateral link weir roughness was changed from Manning’s ‘n’ = 0.05 to Manning’s ‘n’ = 0.015 and this did not have any material impact on any of the model results.

The parameters from this analysis which are deemed to have the greatest impact on the model results are the peak discharge and the grid resolution. In other words, the uncertainty in relation to the discharge and the grid resolution is higher than in relation to the floodplain roughness or link weir roughness.

A second sensitivity analysis was undertaken comparing the results of the High End Future Scenario River Dodder models with those from the Average Future Scenario models. The results of this analysis indicate that in the upper reaches of the river channel the increase in input flows has a minimal impact on flood outline, water level or velocity. This can be attributed to the steep nature of the river valley through this reach.

However, the effect of the High End Future Scenario on the Lower reaches of the Dodder River is much more significant. This is due to the flat topography in this area and the large increase in the tidal water level boundary.


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5 FLUVIAL DISCHARGE DESIGN EVENT ANALYSIS

Examination of the historic hydrological data has shown that flood events on the River Dodder Main Channel and those on its five major tributaries are relatively independent. In other words, the storm events that result in flooding on one river may cause little or no flooding on another. To quantify the independence or conversely the dependency of one river with another within the River Dodder Catchment, a dependence analysis was undertaken. The key objective of the dependence analysis is to derive the design flows for the ten separate hydraulic river models used in this CFRAMS. The underlying concept assumes that the dependence of events in paired sub-catchments is independent of the probability of occurrence and thus using a unit dependence relationship, the discharge relationship of each pair of sub-catchments can be derived. 5.1 METHODOLOGY

5.1.1 Data Analysis

As part of the hydrological analysis for the River Dodder CFRAMS, simulated discharge files were produced by running all available historic rainfall data on each of the 14 Present Day ‘sub-catchment’ rainfall-runoff models. The simulated discharge files have a time-step of 15 minutes and extend from 1967 to 2006. All 14 simulated discharge files were compiled to produce a cumulated discharge total for every time-step. A peak value analysis was then carried out on this cumulated discharge file and the largest 149 events were extracted. The contribution of each of the ‘sub-catchment’ simulated discharge files to these 149 events was then further investigated.

5.1.2 Joint Probability Analysis

To ascertain the dependency between the discharge from any two ‘sub-catchments’ the following methodology steps were employed:

Step 1 The contribution from the sub-catchments to each of the 149 largest events was extracted.

Step 2 Two-dimensional histograms were created by grouping together the number of events belonging to a particular interval or bin of discharge for each of the two sub-catchments. This produced a matrix of events showing the relationship of occurrence of discharge bands for each pair of sub-catchments. An example histogram presenting the joint occurrence of particular events from the Whitechurch NAM and Owendoher NAM simulated discharge files is shown in Table 5-1. The values in the table are the number of occurrences of a particular joint event, e.g. there were 14 events (out of the 149 cumulated large events) where the discharge from the Whitechurch NAM model was between 4 and 6m3/s and the discharge from the Owendoher NAM was between 6 and 8m3/s. Matlab was used in the creation of the histograms to expedite the process.

Figure 5-1 presents a diagram of the Owendoher NAM and Whitechurch NAM sub-catchments.


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Figure 5-1 Rainfall-Runoff Sub-Catchment Diagram


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Table 5-1 Example Histogram

Step 3 Probabilities were assigned to the events in the histograms by calculating the number of occurrences of particular combinations of events in the period of record (1967 – 2006). Table 5-2 presents the probabilities associated with Table 5-1. For example the probability of having an event of ≤ 6m3/s from the Whitechurch NAM model and ≤ 8m3/s from the Owendoher NAM is 1.561 (1 in 0.64 years).

Whitechurch NAM Discharge Bands - m3/s 0 0-2 2-4 4-6 6-8 8-10 10-12 12-14 14-16 16-18 18-20 > 20

0 3.634 3.317 2.634 1.683 0.707 0.390 0.220 0.146 0.049 0.024 0.024 0.0000-2 3.610 3.317 2.634 1.683 0.707 0.390 0.220 0.146 0.049 0.024 0.024 0.0002-4 3.610 3.317 2.634 1.683 0.707 0.390 0.220 0.146 0.049 0.024 0.024 0.0004-6 3.439 3.195 2.634 1.683 0.707 0.390 0.220 0.146 0.049 0.024 0.024 0.0006-8 2.829 2.634 2.268 1.561 0.683 0.390 0.220 0.146 0.049 0.024 0.024 0.000

8-10 1.878 1.780 1.610 1.146 0.610 0.366 0.195 0.122 0.049 0.024 0.024 0.00010-12 1.098 1.024 1.000 0.854 0.585 0.341 0.171 0.098 0.024 0.000 0.000 0.00012-14 0.537 0.512 0.488 0.463 0.415 0.268 0.171 0.098 0.024 0.000 0.000 0.00014-16 0.366 0.366 0.366 0.341 0.317 0.220 0.122 0.073 0.000 0.000 0.000 0.00016-18 0.293 0.293 0.293 0.268 0.244 0.171 0.122 0.073 0.000 0.000 0.000 0.00018-20 0.146 0.146 0.146 0.146 0.146 0.122 0.073 0.049 0.000 0.000 0.000 0.00020-22 0.098 0.098 0.098 0.098 0.098 0.073 0.049 0.024 0.000 0.000 0.000 0.00022-24 0.073 0.073 0.073 0.073 0.073 0.073 0.049 0.024 0.000 0.000 0.000 0.00024-26 0.024 0.024 0.024 0.024 0.024 0.024 0.000 0.000 0.000 0.000 0.000 0.000

Ow

endo

her N

AM

Dis

char

ge B

ands

- m

3 /s

> 26 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000

Table 5-2 Example Probabilities

Whitechurch NAM Discharge Bands (m3/s) 0 0-2 2-4 4-6 6-8 8-10 10-12 12-14 14-16 16-18 18-20 > 20

0 1 0 0 0 0 0 0 0 0 0 0 0 0-2 0 0 0 0 0 0 0 0 0 0 0 0 2-4 2 5 0 0 0 0 0 0 0 0 0 0 4-6 2 8 10 4 1 0 0 0 0 0 0 0 6-8 4 8 10 14 2 0 0 1 0 0 0 0 8-10 1 6 13 11 0 0 0 0 0 0 1 0 10-12 2 0 5 9 4 3 0 0 0 0 0 0 12-14 1 1 0 1 2 0 1 0 1 0 0 0 14-16 0 0 0 0 1 2 0 0 0 0 0 0 16-18 0 0 1 1 2 0 1 1 0 0 0 0 18-20 0 0 0 0 0 1 0 1 0 0 0 0 20-22 0 0 0 0 1 0 0 0 0 0 0 0 22-24 0 0 0 0 0 0 1 1 0 0 0 0 24-26 0 0 0 0 0 1 0 0 0 0 0 0

Ow

endo

her N

AM

Dis

char

ge B

ands

(m3 /s

)

> 26 0 0 0 0 0 0 0 0 0 0 0 0


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Step 4 Contour lines of equal probability were produced from these tables of probabilities using Matlab. Example probability lines from the Whitechurch NAM and Owendoher NAM joint occurrence events are presented in Figure 5-2.

Contour Lines of Equal Probability

0

2

4

6

8

10

12

0 1 2 3 4 5 6 7 8

Interval Number (Whitechurch NAM)

Inte

rval

Num

ber (

Ow

endo

her N

AM)

1 in 10 Year 1 in 4 Year1 in 2 Year1 in 1 Year1 in 1/2 Year1 in 1/3 Year

Figure 5-2 Example Contour Lines of Equal Probability

The axes of the graph refer to the discharge bands in Table 5-2, e.g discharge band number 1 = 0, discharge number 2 = 0 to 2, discharge band 3 = 2 to 4, etc. The shape of the lines describes the dependency of the two ‘sub-catchment’ rainfall-runoff models.

Step 5 The shapes of the contour lines were extracted from the probability diagrams and unit lines produced. The unit line describing the dependency of the Whitechurch NAM and Owendoher NAM is presented in Figure 5-3.


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Unit Line of Probability

0.000

0.200

0.400

0.600

0.800

1.000

1.200

0.000 0.200 0.400 0.600 0.800 1.000 1.200

Whitechurch NAM

Ow

endo

her N

AM

Figure 5-3 Example Unit Line

The design flows of known return period were then mapped onto the unit lines to describe the dependency in terms of discharge. For example, the 100 year joint probability event on the Whitechurch NAM and the Owendoher NAM is presented in

Figure 5-4.

1 in 100 Year Joint Probability Event

0

5

10

15

20

25

30

0 10 20 30 40

Whitechurch NAM Discharge (m3/s)

Ow

endo

her N

AM D

isch

arge

(m3 /s

)

1 in 100 Year

Figure 5-4 Example 1 in 100 Year Joint Probability Diagram


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Figure 5-4 illustrates that a 1 in 100 year event is equivalent to:

• 1 in 100 year event on Whitechurch NAM (27.07m3/s) + Zero (or minimal flow) on Owendoher NAM

• 1 in 100 year event on Owendoher NAM (33.8m3/s) + Zero (or minimal flow) on Whitechurch NAM

• A combination of flows on the Owendoher NAM and Whitechurch NAM which fall along the 1 in 100 Year probability contour. Table 5-3 presents some combinations of flows which are equivalent to a 1 in 100 Year event.

1 in 100 Year Return Period Joint Probability Events

Whitechurch Owendoher NAM Sum [m3/s] [m3/s] [m3/s] 27.1 0.0 27.1 27.1 5.5 32.5 27.1 10.9 38.0 27.1 16.4 43.5 26.6 21.9 48.5 23.9 27.4 51.3 21.9 30.1 52.1 14.6 32.8 47.5 7.3 33.1 40.4 0.0 33.8 33.8

Table 5-3 Example 1 in 100 Year Joint Probability Event Discharges

The highest combined flow or worst-case scenario flow from the Whitechurch NAM and Owendoher NAM for the 1 in 100 Year joint probability event is 52.1m3/s and is highlighted in Table 5-3. This is a combination of 21.9m3/s from the Whitechurch NAM and 30.1m3/s from the Owendoher NAM. This therefore constitutes the design flow for the river section immediately downstream of the confluence of the Owendoher and Whitechurch.

Equally the design discharges (and ultimately the water levels) for the relevant back water scenarios can be identified from this analysis. In this case a discharge of 27.1m3/s for the Whitechurch should be combined with a discharge of 16.4m3/s for the Owendoher to get the backwater relationship for the Whitechurch, secondly a discharge of 33.1m3/s for the Owendoher should be combined with a discharge of 7.3m3/s for the Whitechurch to obtain the worst flood extend for the Owendoher.

Step 6 Dependence tables of discharges as per Table 5-3 have been prepared for all required combinations of ‘sub-catchment’ rainfall-runoff models for the 2, 5, 10, 25, 50, 100, 200 and 1000 year return periods for Present Day and Future scenarios. The worst-case scenario combined flows will be used in the hydraulic models to simulate design events.


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5.2 RESULTS

Full results from the dependence analysis undertaken for the Present Day scenario are presented in the following tables. Figure 5-5 shows the location of the Rainfall-Runoff Catchments. The future scenario results and Rainfall-Runoff Catchment map is presented in Appendix B.


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Figure 5-5 Rainfall-Runoff Catchment Locations


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5.2.1 Dodder Main Channel and Tallaght Stream

A dependence analysis was carried out on the flows from the Tallaght Stream tributary catchment and those from the Dodder Main Channel upstream of the confluence with the Tallaght Stream. The results of this analysis are presented in Table 5-4 to Table 5-7. The highlighted flows are those that are used in the hydraulic models. The first highlighted row in the tables shows the worst case scenario downstream boundary for the Tallaght Stream model and the second highlighted row shows the worst case scenario Tallaght Stream input flow to the Dodder model.

2 Year Joint Probability 5 Year Joint Probability

Tallaght Dodder Main Sum Tallaght Dodder

Main Sum

6.900 0.000 6.900 9.080 0.000 9.080 6.900 8.976 15.876 9.080 11.112 20.192 6.900 17.952 24.852 9.080 22.224 31.304 6.830 26.928 33.758 8.988 33.336 42.324 6.261 35.904 42.165 8.239 44.448 52.687 5.855 39.644 45.499 7.704 49.078 56.782 5.001 44.880 49.881 6.581 55.560 62.141 4.391 47.872 52.263 5.778 59.264 65.042 2.927 53.482 56.409 3.852 66.209 70.061 2.718 53.856 56.574 3.577 66.672 70.249 1.464 55.779 57.243 1.926 69.053 70.979 0.000 56.100 56.100 0.000 69.450 69.450 Max 57.243 Max 70.979

Table 5-4 Dodder Main Channel and Tallaght Stream 2 and 5 year Return Period

10 Year Joint Probability 25 Year Joint Probability Tallaght Dodder Main Sum Tallaght Dodder Main Sum 10.750 0.000 10.750 13.230 0.000 13.230 10.750 13.208 23.958 13.230 16.544 29.774 10.750 26.416 37.166 13.230 33.088 46.318 10.641 39.624 50.265 13.096 49.632 62.728 9.755 52.832 62.587 12.005 66.176 78.181 9.121 58.335 67.457 11.225 73.069 84.295 7.791 66.040 73.831 9.588 82.720 92.308 6.841 70.443 77.284 8.419 88.235 96.654 4.561 78.698 83.258 5.613 98.575 104.187 4.235 79.248 83.483 5.212 99.264 104.476 2.280 82.078 84.359 2.806 102.809 105.616 0.000 82.550 82.550 0.000 103.400 103.400 Max 84.359 Max 105.616



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Tallaght Dodder Main Sum Tallaght Dodder

Main Sum

15.410 0.000 15.410 17.890 0.000 17.890 15.410 19.618 35.028 17.890 23.280 41.170 15.410 39.235 54.645 17.890 46.560 64.450 15.254 58.853 74.107 17.709 69.840 87.549 13.983 78.470 92.454 16.234 93.120 109.354 13.075 86.644 99.720 15.179 102.820 117.999 11.168 98.088 109.256 12.966 116.400 129.366 9.806 104.627 114.434 11.385 124.160 135.545 6.538 116.888 123.426 7.590 138.710 146.300 6.071 117.706 123.776 7.048 139.680 146.728 3.269 121.909 125.178 3.795 144.669 148.463 0.000 122.610 122.610 0.000 145.500 145.500 Max 125.178 Max 148.463


200 Year Joint Probability 1000 Year Joint Probability Tallaght Dodder Main Sum Tallaght Dodder Main Sum 20.740 0.000 20.740 29.140 0.000 29.140 20.740 27.658 48.398 29.140 41.442 70.582 20.740 55.315 76.055 29.140 82.883 112.023 20.531 82.973 103.503 28.846 124.325 153.170 18.820 110.630 129.450 26.442 165.766 192.208 17.598 122.154 139.752 24.725 183.034 207.759 15.031 138.288 153.319 21.119 207.208 228.327 13.198 147.507 160.705 18.544 221.022 239.566 8.799 164.793 173.592 12.362 246.923 259.285 8.170 165.946 174.116 11.479 248.650 260.129 4.399 171.872 176.272 6.181 257.530 263.711 0.000 172.860 172.860 0.000 259.010 259.010 Max 176.272 Max 263.711



MDW0259Rp0021 68 Rev F01

5.2.2 Dodder Main Channel and Dodder Urban 1

A dependence analysis was carried out on the flows from the Dodder Urban 1 catchment and those from the Dodder Main Channel upstream of the confluence with the Dodder Urban 1 catchment. The results of this analysis are presented in Table 5-8 to Table 5-11. The highlighted flows are those that are used in the hydraulic models.

2 Year Joint Probability 5 Year Joint Probability Dodder Urban 1 Dodder Main Sum Dodder

Urban 1 Dodder Main Sum

1.950 0.000 1.950 2.850 0.000 2.850 1.950 10.139 12.089 2.850 12.720 15.570 1.950 20.277 22.227 2.850 25.441 28.291 1.950 30.416 32.366 2.850 38.161 41.011 1.913 40.555 42.467 2.795 50.882 53.677 1.523 50.693 52.216 2.226 63.602 65.828 1.038 57.790 58.829 1.518 72.507 74.024 0.808 60.832 61.639 1.180 76.323 77.503 0.000 67.700 67.700 0.000 84.940 84.940 Max 67.700 Max 84.940

Table 5-8 Dodder Main Channel and Dodder Urban 1 - 2 and 5 year Return Period



3.650 0.000 3.650 4.870 0.000 4.870 3.650 15.197 18.847 4.870 19.114 23.984 3.650 30.395 34.045 4.870 38.227 43.097 3.650 45.592 49.242 4.870 57.341 62.211 3.580 60.790 64.370 4.777 76.455 81.231 2.850 75.987 78.838 3.803 95.568 99.372 1.944 86.626 88.569 2.593 108.948 111.541 1.512 91.185 92.697 2.017 114.682 116.699 0.000 101.480 101.480 0.000 127.630 127.630 Max 101.480 Max 127.630



MDW0259Rp0021 69 Rev F01

50 Year Joint Probability 100 Year Joint Probability Dodder Urban 1

Dodder Upper Sum Dodder

Urban 1 Dodder Upper Sum

5.990 0.000 5.990 7.320 0.000 7.320 5.990 22.712 28.702 7.320 26.989 34.309 5.990 45.425 51.415 7.320 53.979 61.299 5.990 68.137 74.127 7.320 80.968 88.288 5.875 90.849 96.725 7.180 107.958 115.138 4.678 113.562 118.240 5.717 134.947 140.664 3.189 129.460 132.650 3.898 153.840 157.738 2.481 136.274 138.755 3.032 161.937 164.968 0.000 151.660 151.660 0.000 180.220 180.220 Max 151.660 Max 180.220


200 Year Joint Probability 1000 Year Joint Probability Dodder Urban 1

Dodder Upper Sum Dodder

Urban 1 Dodder Upper Sum

8.910 0.000 8.910 13.930 0.000 13.930 8.910 32.093 41.003 13.930 48.129 62.059 8.910 64.186 73.096 13.930 96.259 110.189 8.910 96.280 105.190 13.930 144.388 158.318 8.739 128.373 137.112 13.663 192.517 206.181 6.958 160.466 167.424 10.879 240.647 251.526 4.744 182.931 187.676 7.417 274.337 281.755 3.690 192.559 196.249 5.769 288.776 294.545 0.000 214.300 214.300 0.000 321.380 321.380 Max 214.300 Max 321.380



MDW0259Rp0021 70 Rev F01

5.2.3 Dodder Main Channel and Owendoher / Whitechurch

A dependence analysis was carried out on the flows from the Owendoher / Whitechurch tributary catchment and those from the Dodder Main Channel upstream of the confluence with the Owendoher / Whitechurch. The results of this analysis are presented in

2 Year Joint Probability 5 Year Joint Probability Owendoher Dodder Main Sum Owendoher Dodder Main Sum

27.480 0.000 27.480 35.390 0.000 35.390 27.480 20.637 48.117 35.390 26.012 61.402 27.480 41.274 68.754 35.390 52.024 87.414 27.253 43.338 70.591 35.098 54.625 89.722 26.612 51.593 78.204 34.272 65.030 99.301 24.528 61.174 85.702 31.588 77.107 108.694 24.073 61.911 85.984 31.003 78.036 109.038 21.802 64.491 86.293 28.078 81.287 109.365 19.077 67.070 86.147 24.568 84.539 109.107 16.352 68.544 84.896 21.059 86.397 107.455 13.626 68.672 82.298 17.549 86.557 104.105 10.901 69.005 79.906 14.039 86.977 101.016 8.176 69.328 77.503 10.529 87.384 97.913 5.451 69.328 74.778 7.020 87.384 94.403 2.725 69.328 72.053 3.510 87.384 90.893 0.000 69.650 69.650 0.000 87.790 87.790

Max 86.293 Max 109.365Table 5-12 to Table 5-15. The highlighted flows are those that are used in the hydraulic models. The first highlighted row in the tables shows the worst case scenario downstream boundary for the Owendoher model and the second highlighted row shows the worst case scenario Owendoher input flow to the Dodder model.


27.480 0.000 27.480 35.390 0.000 35.390 27.480 20.637 48.117 35.390 26.012 61.402 27.480 41.274 68.754 35.390 52.024 87.414 27.253 43.338 70.591 35.098 54.625 89.722 26.612 51.593 78.204 34.272 65.030 99.301 24.528 61.174 85.702 31.588 77.107 108.694 24.073 61.911 85.984 31.003 78.036 109.038 21.802 64.491 86.293 28.078 81.287 109.365 19.077 67.070 86.147 24.568 84.539 109.107 16.352 68.544 84.896 21.059 86.397 107.455 13.626 68.672 82.298 17.549 86.557 104.105 10.901 69.005 79.906 14.039 86.977 101.016 8.176 69.328 77.503 10.529 87.384 97.913 5.451 69.328 74.778 7.020 87.384 94.403 2.725 69.328 72.053 3.510 87.384 90.893 0.000 69.650 69.650 0.000 87.790 87.790

Max 86.293 Max 109.365

Table 5-12 Dodder Main Channel and Owendoher - 2 and 5 year Return Period


MDW0259Rp0021 71 Rev F01


42.160 0.000 42.160 52.220 0.000 52.220 42.160 31.150 73.310 52.220 39.259 91.479 42.160 62.299 104.459 52.220 78.519 130.739 41.812 65.414 107.226 51.788 82.444 134.233 40.828 77.874 118.702 50.570 98.148 148.718 37.630 92.336 129.967 46.610 116.376 162.985 36.934 93.449 130.382 45.746 117.778 163.524 33.449 97.343 130.792 41.431 122.685 164.116 29.268 101.236 130.504 36.252 127.593 163.844 25.087 103.461 128.548 31.073 130.397 161.470 20.906 103.653 124.559 25.894 130.639 156.533 16.725 104.157 120.881 20.715 131.273 151.989 12.543 104.643 117.187 15.537 131.887 147.423 8.362 104.643 113.006 10.358 131.887 142.244 4.181 104.643 108.824 5.179 131.887 137.065 0.000 105.130 105.130 0.000 132.500 132.500

Max 130.792 Max 164.116



60.990 0.000 60.990 71.020 0.000 71.020 60.990 46.711 107.701 71.020 55.567 126.587 60.990 93.422 154.412 71.020 111.135 182.155 60.486 98.093 158.579 70.433 116.692 187.125 59.063 116.778 175.841 68.776 138.919 207.694 54.437 138.465 192.902 63.390 164.718 228.107 53.429 140.133 193.563 62.216 166.702 228.918 48.389 145.972 194.361 56.346 173.648 229.995 42.340 151.811 194.151 49.303 180.594 229.897 36.292 155.148 191.439 42.260 184.563 226.823 30.243 155.435 185.678 35.217 184.905 220.122 24.194 156.190 180.385 28.173 185.804 213.977 18.146 156.920 175.066 21.130 186.672 207.802 12.097 156.920 169.017 14.087 186.672 200.758 6.049 156.920 162.969 7.043 186.672 193.715 0.000 157.650 157.650 0.000 187.540 187.540

Max 194.361 Max 229.995



82.500 0.000 82.500 116.280 0.000 116.280 82.500 66.136 148.636 116.280 99.351 215.631 82.500 132.273 214.773 116.280 198.702 314.982 81.818 138.886 220.704 115.319 208.637 323.956 79.893 165.341 245.234 112.606 248.378 360.983 73.636 196.047 269.683 103.787 294.505 398.292


MDW0259Rp0021 72 Rev F01

72.273 198.409 270.682 101.865 298.053 399.918 65.455 206.676 272.130 92.255 310.472 402.727 57.273 214.943 272.216 80.723 322.891 403.614 49.091 219.667 268.758 69.191 329.988 399.179 40.909 220.074 260.983 57.660 330.599 388.259 32.727 221.143 253.871 46.128 332.205 378.333 24.545 222.177 246.722 34.596 333.758 368.353 16.364 222.177 238.540 23.064 333.758 356.821 8.182 222.177 230.358 11.532 333.758 345.290 0.000 223.210 223.210 0.000 335.310 335.310

Max 272.216 Max 403.614



MDW0259Rp0021 73 Rev F01

5.2.4 Dodder Main Channel and Little Dargle

A dependence analysis was carried out on the flows from the Little Dargle tributary catchment and those from the Dodder Main Channel upstream of the confluence with the Little Dargle. The results of this analysis are presented in Table 5-16 to Table 5-19. The highlighted flows are those that are used in the hydraulic models. The first highlighted row in the tables shows the worst case scenario downstream boundary for the Little Dargle model and the second highlighted row shows the worst case scenario Little Dargle input flow to the Dodder model.

2 Year Joint Probability 5 Year Joint Probability Little Dargle Dodder Main Sum Little Dargle Dodder Main Sum

11.660 0.000 11.660 14.690 0.000 14.690 11.660 12.664 24.324 14.690 15.962 30.652 11.660 25.327 36.987 14.690 31.924 46.614 11.322 37.991 49.313 14.264 47.885 62.149 10.411 50.655 61.065 13.116 63.847 76.963 10.411 50.655 61.065 13.116 63.847 76.963 8.329 58.849 67.177 10.493 74.176 84.668 7.287 63.318 70.606 9.181 79.809 88.990 6.246 66.936 73.183 7.870 84.370 92.239 4.164 67.923 72.087 5.246 85.613 90.860 2.082 68.824 70.906 2.623 86.749 89.372 0.000 69.650 69.650 0.000 87.790 87.790 Max 73.183 Max 92.239

Table 5-16 Dodder Main Channel and Little Dargle - 2 and 5 year Return Period


Little Dargle Dodder Upper Sum Little Dargle Dodder

Upper Sum

17.560 0.000 17.560 21.790 0.000 21.790 17.560 19.115 36.675 21.790 24.091 45.881 17.560 38.229 55.789 21.790 48.182 69.972 17.050 57.344 74.394 21.158 72.273 93.430 15.679 76.458 92.137 19.455 96.364 115.819 15.679 76.458 92.137 19.455 96.364 115.819 12.543 88.826 101.369 15.564 111.952 127.516 10.975 95.573 106.548 13.619 120.455 134.073 9.407 101.034 110.441 11.673 127.338 139.011 6.271 102.523 108.795 7.782 129.215 136.997 3.136 103.883 107.019 3.891 130.929 134.820 0.000 105.130 105.130 0.000 132.500 132.500 Max 110.441 Max 139.011



MDW0259Rp0021 74 Rev F01


25.440 0.000 25.440 29.560 0.000 29.560 25.440 28.664 54.104 29.560 34.098 63.658 25.440 57.327 82.767 29.560 68.196 97.756 24.702 85.991 110.693 28.702 102.295 130.997 22.714 114.655 137.369 26.393 136.393 162.786 22.714 114.655 137.369 26.393 136.393 162.786 18.171 133.202 151.373 21.114 158.456 179.571 15.900 143.318 159.218 18.475 170.491 188.966 13.629 151.508 165.136 15.836 180.233 196.069 9.086 153.741 162.827 10.557 182.890 193.447 4.543 155.781 160.323 5.279 185.316 190.595 0.000 157.650 157.650 0.000 187.540 187.540 Max 165.136 Max 196.069



34.230 0.000 34.230 47.660 0.000 47.660 34.230 40.584 74.814 47.660 60.965 108.625 34.230 81.167 115.397 47.660 121.931 169.591 33.237 121.751 154.988 46.277 182.896 229.173 30.562 162.335 192.897 42.554 243.862 286.415 30.562 162.335 192.897 42.554 243.862 286.415 24.450 188.595 213.045 34.043 283.310 317.353 21.394 202.918 224.312 29.787 304.827 334.615 18.337 214.514 232.851 25.532 322.246 347.778 12.225 217.676 229.901 17.021 326.997 344.018 6.112 220.563 226.676 8.511 331.334 339.845 0.000 223.210 223.210 0.000 335.310 335.310 Max 232.851 Max 347.778



MDW0259Rp0021 75 Rev F01

5.2.5 Dodder Main Channel and Dodder Urban 2

A dependence analysis was carried out on the flows from the Dodder Urban 2 catchment and those from the Dodder Main Channel upstream of the confluence with the Dodder Urban 2 catchment. The results of this analysis are presented in Table 5-20 to



35.100 0.000 35.100 61.630 0.000 61.630 35.100 39.531 74.631 61.630 58.395 120.025 35.100 79.063 114.163 61.630 116.791 178.421 35.100 118.594 153.694 61.630 175.186 236.816 35.100 158.126 193.226 61.630 233.581 295.211 33.833 197.657 231.491 59.406 291.976 351.382 29.921 237.189 267.109 52.536 350.372 402.907 25.133 268.814 293.947 44.130 397.088 441.218 23.655 276.720 300.375 41.534 408.767 450.301 12.567 300.439 313.006 22.065 443.804 465.869 0.000 305.710 305.710 0.000 451.590 451.590

Max 313.006 Max 465.869Table 5-23. The highlighted flows are those that are used in the hydraulic models.



6.970 0.000 6.970 9.410 0.000 9.410 6.970 12.560 19.530 9.410 15.928 25.338 6.970 25.120 32.090 9.410 31.857 41.267 6.970 37.680 44.650 9.410 47.785 57.195 6.970 50.240 57.210 9.410 63.714 73.124 6.718 62.800 69.518 9.070 79.642 88.713 5.942 75.359 81.301 8.021 95.571 103.592 4.991 85.407 90.398 6.738 108.313 115.051 4.697 87.919 92.617 6.342 111.499 117.841 2.495 95.455 97.951 3.369 121.056 124.425 0.000 97.130 97.130 0.000 123.180 123.180

Max 97.951 Max 124.425




12.180 0.000 12.180 16.920 0.000 16.920 12.180 19.046 31.226 16.920 23.886 40.806 12.180 38.092 50.272 16.920 47.772 64.692 12.180 57.138 69.318 16.920 71.659 88.579 12.180 76.184 88.364 16.920 95.545 112.465 11.740 95.231 106.971 16.309 119.431 135.740 10.383 114.277 124.659 14.423 143.317 157.741


MDW0259Rp0021 76 Rev F01

8.721 129.514 138.235 12.116 162.426 174.542 8.208 133.323 141.531 11.403 167.203 178.606 4.361 144.751 149.111 6.058 181.535 187.593 0.000 147.290 147.290 0.000 184.720 184.720

Max 149.111 Max 187.593




21.600 0.000 21.600 27.540 0.000 27.540 21.600 28.272 49.872 27.540 33.434 60.974 21.600 56.545 78.145 27.540 66.869 94.409 21.600 84.817 106.417 27.540 100.303 127.843 21.600 113.090 134.690 27.540 133.738 161.278 20.821 141.362 162.183 26.546 167.172 193.719 18.413 169.634 188.047 23.476 200.607 224.083 15.467 192.252 207.719 19.720 227.354 247.074 14.557 197.907 212.464 18.560 234.041 252.601 7.733 214.870 222.604 9.860 254.102 263.962 0.000 218.640 218.640 0.000 258.560 258.560

Max 222.604 Max 263.962




35.100 0.000 35.100 61.630 0.000 61.630 35.100 39.531 74.631 61.630 58.395 120.025 35.100 79.063 114.163 61.630 116.791 178.421 35.100 118.594 153.694 61.630 175.186 236.816 35.100 158.126 193.226 61.630 233.581 295.211 33.833 197.657 231.491 59.406 291.976 351.382 29.921 237.189 267.109 52.536 350.372 402.907 25.133 268.814 293.947 44.130 397.088 441.218 23.655 276.720 300.375 41.534 408.767 450.301 12.567 300.439 313.006 22.065 443.804 465.869 0.000 305.710 305.710 0.000 451.590 451.590

Max 313.006 Max 465.869



MDW0259Rp0021 77 Rev F01

5.2.6 Dodder Main Channel and Dundrum / Slang

A dependence analysis was carried out on the flows from the Dundrum / Slang tributary catchment and those from the Dodder Main Channel upstream of the confluence with the Dundrum / Slang. The results of this analysis are presented in Table 5-24 to Table 5-27. The highlighted flows are those that are used in the hydraulic models. The first highlighted row in the tables shows the worst case scenario downstream boundary for the Dundrum model and the second highlighted row shows the worst case scenario Dundrum input flow to the Dodder model.

2 Year Joint Probability 5 Year Joint Probability Dundrum Dodder Main Sum Dundrum Dodder Main Sum

8.020 0.000 8.020 11.180 0.000 11.180 8.020 12.141 20.161 11.180 15.398 26.578 8.020 24.283 32.303 11.180 30.795 41.975 8.020 36.424 44.444 11.180 46.193 57.373 8.020 48.565 56.585 11.180 61.590 72.770 8.020 60.706 68.726 11.180 76.988 88.168 7.244 72.848 80.091 10.098 92.385 102.483 6.209 84.989 91.198 8.655 107.783 116.438 6.209 84.989 91.198 8.655 107.783 116.438 4.139 95.213 99.352 5.770 120.749 126.519 2.070 96.602 98.672 2.885 122.511 125.396 0.000 97.130 97.130 0.000 123.180 123.180 Max 99.352 Max 126.519

Table 5-24 Dodder Main Channel and Dundrum / Slang - 2 and 5 year Return Period


14.380 0.000 14.380 20.030 0.000 20.030 14.380 18.411 32.791 20.030 23.090 43.120 14.380 36.823 51.203 20.030 46.180 66.210 14.380 55.234 69.614 20.030 69.270 89.300 14.380 73.645 88.025 20.030 92.360 112.390 14.380 92.056 106.436 20.030 115.450 135.480 12.988 110.468 123.456 18.092 138.540 156.632 11.133 128.879 140.012 15.507 161.630 177.137 11.133 128.879 140.012 15.507 161.630 177.137 7.422 144.383 151.805 10.338 181.074 191.412 3.711 146.490 150.200 5.169 183.716 188.885 0.000 147.290 147.290 0.000 184.720 184.720 Max 151.805 Max 191.412



MDW0259Rp0021 78 Rev F01


25.770 0.000 25.770 33.210 0.000 33.210 25.770 27.330 53.100 33.210 32.320 65.530 25.770 54.660 80.430 33.210 64.640 97.850 25.770 81.990 107.760 33.210 96.960 130.170 25.770 109.320 135.090 33.210 129.280 162.490 25.770 136.650 162.420 33.210 161.600 194.810 23.276 163.980 187.256 29.996 193.920 223.916 19.951 191.310 211.261 25.711 226.240 251.951 19.951 191.310 211.261 25.711 226.240 251.951 13.301 214.325 227.625 17.141 253.457 270.597 6.650 217.452 224.102 8.570 257.155 265.725 0.000 218.640 218.640 0.000 258.560 258.560 Max 227.625 Max 270.597



42.860 0.000 42.860 77.990 0.000 77.990 42.860 38.214 81.074 77.990 56.449 134.439 42.860 76.428 119.288 77.990 112.898 190.888 42.860 114.641 157.501 77.990 169.346 247.336 42.860 152.855 195.715 77.990 225.795 303.785 42.860 191.069 233.929 77.990 282.244 360.234 38.712 229.283 267.995 70.443 338.693 409.135 33.182 267.496 300.678 60.379 395.141 455.521 33.182 267.496 300.678 60.379 395.141 455.521 22.121 299.676 321.798 40.253 442.677 482.930 11.061 304.049 315.109 20.126 449.136 469.262 0.000 305.710 305.710 0.000 451.590 451.590 Max 321.798 Max 482.930



MDW0259Rp0021 79 Rev F01

5.2.7 Dodder Main Channel and Dodder Urban 3+4

A dependence analysis was carried out on the flows from the Dodder Urban 3+4 catchment and those from the Dodder Main Channel upstream of the confluence with the Dodder Urban 3+4 catchment. The results of this analysis are presented in Table 5-28 to Table 5-31. The highlighted flows are those that are used in the hydraulic models.

2 Year Joint Probability 5 Year Joint Probability Dodder

Urban 3+4 Dodder Main Sum Dodder Urban 3+4 Dodder Main Sum

5.770 0.000 5.770 8.040 0.000 8.040 5.770 13.269 19.039 8.040 17.014 25.054 5.770 26.537 32.307 8.040 34.028 42.068 5.770 39.806 45.576 8.040 51.043 59.083 5.770 53.075 58.845 8.040 68.057 76.097 5.770 66.343 72.113 8.040 85.071 93.111 5.209 79.612 84.821 7.259 102.085 109.344 4.775 84.035 88.810 6.654 107.757 114.410 3.979 92.880 96.860 5.545 119.099 124.644 2.835 106.149 108.984 3.951 136.114 140.064 2.388 108.361 110.748 3.327 138.949 142.276 0.000 112.120 112.120 0.000 143.770 143.770 Max 112.120 Max 143.770

Table 5-28 Dodder Main Channel and Dodder Urban 3+4 - 2 and 5 year Return Period



10.010 0.000 10.010 13.200 0.000 13.200 10.010 20.574 30.584 13.200 26.233 39.433 10.010 41.148 51.158 13.200 52.466 65.666 10.010 61.722 71.732 13.200 78.699 91.899 10.010 82.296 92.306 13.200 104.933 118.133 10.010 102.870 112.880 13.200 131.166 144.366 9.037 123.444 132.481 11.917 157.399 169.316 8.284 130.302 138.586 10.924 166.143 177.067 6.903 144.018 150.921 9.103 183.632 192.735 4.919 164.592 169.510 6.486 209.865 216.351 4.142 168.021 172.163 5.462 214.237 219.699 0.000 173.850 173.850 0.000 221.670 221.670 Max 173.850 Max 221.670



MDW0259Rp0021 80 Rev F01



16.220 0.000 16.220 19.890 0.000 19.890 16.220 31.480 47.700 19.890 37.788 57.678 16.220 62.961 79.181 19.890 75.576 95.466 16.220 94.441 110.661 19.890 113.364 133.254 16.220 125.922 142.142 19.890 151.153 171.043 16.220 157.402 173.622 19.890 188.941 208.831 14.644 188.883 203.527 17.957 226.729 244.686 13.423 199.376 212.800 16.461 239.325 255.786 11.186 220.363 231.550 13.717 264.517 278.234 7.970 251.844 259.814 9.774 302.305 312.079 6.712 257.091 263.802 8.230 308.603 316.834 0.000 266.010 266.010 0.000 319.310 319.310 Max 266.010 Max 319.310




24.370 0.000 24.370 39.030 0.000 39.030 24.370 45.405 69.775 39.030 69.966 108.996 24.370 90.809 115.179 39.030 139.931 178.961 24.370 136.214 160.584 39.030 209.897 248.927 24.370 181.619 205.989 39.030 279.863 318.893 24.370 227.024 251.394 39.030 349.828 388.858 22.002 272.428 294.430 35.237 419.794 455.031 20.168 287.563 307.732 32.301 443.116 475.417 16.807 317.833 334.640 26.917 489.760 516.677 11.975 363.238 375.213 19.179 559.725 578.904 10.084 370.805 380.889 16.150 571.386 587.537 0.000 383.670 383.670 0.000 591.210 591.210 Max 383.670 Max 591.210


5.2.8 Owendoher and Whitechurch Stream

A dependence analysis was carried out on the flows from the Owendoher NAM catchment and those from the Whitechurch NAM catchment. The results of this analysis are presented in Table 5-32 to Table 5-35. The highlighted flows are those that are used in the hydraulic models.


MDW0259Rp0021 81 Rev F01

2 Year Joint Probability 5 Year Joint Probability Owendoher Whitechurch Sum Owendoher Whitechurch Sum

0.000 10.430 10.430 0.000 12.740 12.740 2.284 10.430 12.714 2.967 12.740 15.707 4.567 10.430 14.997 5.934 12.740 18.674 6.851 10.430 17.281 8.901 12.740 21.641 9.134 10.258 19.393 11.868 12.530 24.398

11.418 9.225 20.643 14.835 11.268 26.103 12.559 8.457 21.017 16.318 10.330 26.649 13.701 5.638 19.339 17.802 6.887 24.689 13.701 5.638 19.339 17.802 6.887 24.689 13.808 2.819 16.627 17.941 3.443 21.384 14.100 0.000 14.100 18.320 0.000 18.320

Max 21.017 Max 26.649

Table 5-32 Owendoher and Whitechurch - 2 and 5 year Return Period


0.000 15.340 15.340 0.000 19.330 19.330 3.464 15.340 18.804 4.182 19.330 23.512 6.928 15.340 22.268 8.363 19.330 27.693

10.392 15.340 25.732 12.545 19.330 31.875 13.857 15.088 28.944 16.726 19.012 35.738 17.321 13.568 30.889 20.908 17.097 38.005 19.053 12.439 31.491 22.999 15.674 38.673 20.785 8.292 29.077 25.090 10.449 35.539 20.785 8.292 29.077 25.090 10.449 35.539 20.947 4.146 25.093 25.286 5.225 30.510 21.390 0.000 21.390 25.820 0.000 25.820

Max 31.491 Max 38.673



0.000 22.900 22.900 0.000 27.070 27.070 4.791 22.900 27.691 5.474 27.070 32.544 9.581 22.900 32.481 10.948 27.070 38.018

14.372 22.900 37.272 16.422 27.070 43.492 19.162 22.523 41.686 21.896 26.625 48.521 23.953 20.255 44.207 27.370 23.943 51.313 26.348 18.569 44.916 30.107 21.950 52.057 28.743 12.379 41.122 32.844 14.633 47.477 28.743 12.379 41.122 32.844 14.633 47.477 28.968 6.190 35.157 33.100 7.317 40.417 29.580 0.000 29.580 33.800 0.000 33.800

Max 44.916 Max 52.057



MDW0259Rp0021 82 Rev F01


0.000 31.940 31.940 0.000 46.750 46.750 6.240 31.940 38.180 8.421 46.750 55.171

12.480 31.940 44.420 16.843 46.750 63.593 18.720 31.940 50.660 25.264 46.750 72.014 24.960 31.415 56.375 33.686 45.981 79.667 31.200 28.250 59.450 42.107 41.349 83.457 34.320 25.899 60.219 46.318 37.908 84.226 37.440 17.266 54.706 50.529 25.272 75.801 37.440 17.266 54.706 50.529 25.272 75.801 37.732 8.633 46.365 50.924 12.636 63.559 38.530 0.000 38.530 52.000 0.000 52.000

Max 60.219 Max 84.226



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6 DISCHARGE AND TOTAL COASTAL WATER LEVEL JOINT PROBABILITY ANALYSIS

The River Dodder is influenced by both tidal and fluvial events below the weir at Ballsbridge. While it is relatively easy to derive the return periods for each component separately, under certain circumstances both extreme coastal water levels (storm surge) and extreme discharges in the river can occur. This can result in back water effects potentially giving higher water levels compared to the levels expected from fluvial or coastal events on their own. The likelihood of the combination of events is referred to as probability of joint occurrence or joint probability. Essentially typical storm surges are associated with cyclones tracking in from the Atlantic over Ireland occasionally combined with zonal fronts associated with rainfall and strong winds as well as sudden changes in wind direction. For the purposes of this study the joint probability total coastal water levels associated with extreme fluvial discharges have been derived along with the joint probability fluvial discharges associated with extreme total coastal water levels. These data combinations will be used as boundary conditions in the Lower Dodder hydraulic models to simulate extreme flood conditions. The methodology employed in the joint probability analyses is discussed further in the following sections.

6.1 DERIVATION OF EXTREME FLUVIAL DISCHARGES AND JOINT PROBABILITY TOTAL COASTAL WATER LEVELS

The methodology sequence used for the derivation of the total coastal water levels associated with extreme fluvial discharges is presented as a flow chart in Figure 6-1.

Figure 6-1 Methodology Sequence


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6.1.1 Rainfall and Tidal Surge Joint Probability Analysis

As part of the hydrological analysis element of the River Dodder CFRAMS a joint probability analysis was undertaken on the tidal surge residuals and rainfall data.

A statistical analysis of a 27 year data set of rainfall and surge residual values was undertaken to establish the return periods for extreme rainfall and surge residual conditions for use in the joint probability analysis. The analysis was undertaken using the Extreme Value Analysis (EVA) toolbox provided within the MIKE software suite.

The results of the statistical analysis of the surge residuals are presented in graphical format in Figure 6-2.

Figure 6-2 Probability Plot of Extreme Surge Residuals Used in Joint Probability Analysis

The results of the statistical analysis of the rainfall data are presented in graphical format in Figure 6-3.


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Figure 6-3 Probability Plot of Extreme Rainfall Used in Joint Probability Analysis

Based on the results of the analysis of the surge residual and rainfall data, a joint probability analysis was carried out to establish the range of rainfall and surge residual combinations which will provide a 1 in 100 year return period event. The joint probability analysis was carried out by establishing the correlation between rainfall and surge residuals for the joint exceedence return periods within the dataset. This correlation was applied to the extreme rainfall and surge residuals established from the extreme value analysis for the 1 in 100 year return period.

The results of the joint probability analysis are given for return period events ranging from 1 in 1 to 1 in 1000 years. The data is presented in tabular form in Table 6-1, followed by a figure illustrating the data in Figure 6-4.


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Joint Return Period (years)

2 5 10 25 50 100 200 1000 Surge

Residual Level (m) Rainfall (mm)

-0.5 47 65 78 96 110 125 140 176 -0.4 47 65 78 96 110 125 140 176 -0.3 47 65 78 96 110 125 140 176 -0.2 47 64 78 96 110 124 139 175 -0.1 46 64 77 95 109 123 138 174

0 45 63 76 93 107 121 136 171 0.1 42 59 72 89 103 117 131 166 0.2 38 55 67 84 97 111 125 160 0.3 35 50 62 78 91 104 118 152 0.4 31 47 58 74 86 98 112 145 0.5 23 40 52 69 81 94 107 138 0.6 13 31 44 61 74 88 101 133 0.7 n/a 19 32 50 64 78 92 126 0.8 n/a 4 18 37 51 66 81 116 0.9 n/a n/a 0 21 36 51 67 104 1 n/a n/a n/a 0 18 34 50 88

1.1 n/a n/a n/a n/a n/a 13 31 71 1.2 n/a n/a n/a n/a n/a n/a 7 51 1.3 n/a n/a n/a n/a n/a n/a n/a 28

Table 6-1 Joint Probability of Rainfall and Surge Residuals

Figure 6-4 Joint Probability of Rainfall and Surge Residuals


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6.1.2 Relationship between Fluvial Discharge and Rainfall

The 27 year rainfall data set used in the previous analysis (Section 6.1.1) has also been used to establish the relationship between rainfall and fluvial discharge data. This rainfall data set was applied to the Waldron’s Bridge calibrated rainfall runoff model (see Hydrological Analysis Report) and a simulated discharge file produced.

The top 500 discharge events were extracted from the simulated discharge file with an independence criterion of 24 hours between each event. The corresponding antecedent rainfall total for each of these discharge events was extracted from the rainfall data set. The rainfall and discharge data events with a peak discharge of more than 40m3/s were then graphed against each other and a linear trendline applied. The equation of this linear trend line provides the simplified relationship between the discharge and rainfall events. The graph is presented here as Figure 6-5.

Figure 6-5 Discharge V Daily Rainfall

The equation of the linear trendline in Figure 6-5 is y = 2.06x + 9.11 or in words “Discharge = 2.06 x Antecedent Rainfall + 9.11”. The constant discharge of 9.11m3/s can be seen as a base flow preceding the event, though less in terms of groundwater flow but more as runoff from previous rainfall events.

Peak discharges for each of the design events (2, 5, 10, 25, 50, 100, 200 and 1000 year return period) were taken from they Hydrological Analysis Report (Table 5-11). Using the correlation from Figure 6-5 daily rainfall totals were calculated from the design event discharges. These discharges and rainfall totals are presented in Table 6-2.

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

120

140

160

180

200

accum. rainfall [mm]

peak

dis

char

ge [m

3 /s]

Q = 2.06*precip + 9.11

data 1 linear


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Design Event Return Period

(Years)

Discharge at Waldron's

Bridge (m3/s) Daily Rainfall

(mm)

2 74.3 32

5 108.2 47

10 130.6 58

25 159.0 72

50 180.1 82

100 201.0 92

200 221.8 102

1000 270.0 125

Table 6-2 Design Event Discharges and Daily Rainfall Totals

6.1.3 Relationship between Tidal Surge and Total Water Levels

Using Table 6-1 and Figure 6-4 in Section 6.1.1 and the rainfall totals from Table 6-2 in Section 6.1.2, the joint probability surge residuals associated with the daily rainfall values can be deduced. The daily rainfall totals and the associated surge residual levels are presented in Table 6-3.

Joint Probability


Daily Rainfall (mm)

Surge Residual Level (m)

2 32 0.38

5 47 0.40

10 58 0.40

25 72 0.45

50 82 0.48

100 92 0.53

200 102 0.58

1000 125 0.72

Table 6-3 Joint Probability Design Event Daily Rainfall Totals and Surge Residual Levels

A joint probability analysis of astronomical tide and surge residual levels was carried out for the Irish Coastal Protection Strategy Study commissioned by the Dept. of Agriculture, Fisheries and Food (DAFF) for the Dublin Port area. Table 6-4 presents the results of this joint probability analysis.


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Table 6-4 Joint Probability Surge Residual Levels (m)

The surge residual levels in Table 6-3 were paired with an astronomical tide of 0.05 year return period and the associated joint probability return periods deduced. The results are presented in Table 6-5. Values for a return period of less than 2 years were extrapolated using the probability function applied in the analysis.

Joint Probability


Surge Residual Level (m)

Astro Tide & Surge Joint Probability


2 0.38 1.5

5 0.40 1.8

10 0.40 1.8

25 0.45 2.6

50 0.48 3.2

100 0.53 4.7

200 0.58 6.9

1000 0.72 19.8

Table 6-5 Surge Residuals and Tidal Return Periods

6.1.4 Design Event Extreme Fluvial Discharge and Total Coastal Water Level

The design total coastal water levels used for this study have been taken from the Irish Coastal Protection Strategy Study and are presented in Table 6-6.

Joint Probability Period (Years) Astro Tide


Astro Tide (mOD)

2 5 10 25 50 100 200 1000

0.01 1.780 0.603 0.724 0.815 0.923 1.011 1.091 1.170 1.356

0.02 1.887 0.523 0.644 0.735 0.847 0.947 1.039 1.130 1.342

0.05 1.991 0.418 0.538 0.630 0.741 0.842 0.933 1.025 1.237

0.1 2.048 0.338 0.458 0.550 0.661 0.762 0.853 0.945 1.157

0.2 2.091 0.258 0.379 0.470 0.581 0.682 0.773 0.865 1.077

0.5 2.131 0.152 0.273 0.364 0.476 0.577 0.668 0.759 0.971

1 2.153 0.072 0.193 0.285 0.396 0.497 0.588 0.679 0.892

2 2.170 -0.008 0.113 0.205 0.316 0.417 0.508 0.600 0.812

5 2.188 N/A 0.008 0.099 0.210 0.311 0.403 0.494 0.706


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Design Event (Tide) Return

Period (Years)

Total Coastal Water Level

(mOD)

2 2.46

5 2.58

10 2.67

20 2.76

50 2.88

100 2.97

200 3.07

1000 3.28

Table 6-6 Design Event Total Coastal Water Levels

Using the surge residual level return periods from Table 6-5, the associated total coastal water level was interpreted from Table 6-6. Table 6-7 presents the Present Day Scenario design discharge events and the associated total coastal water levels which will be used as input boundaries in the Lower Dodder hydraulic models.


(Years)


Bridge (m3/s)

Astro Tide & Surge Joint Probability



(mOD)

2 74.3 1.5 2.42

5 108.2 1.8 2.44

10 130.6 1.8 2.44

25 159.0 2.6 2.48

50 180.1 3.2 2.51

100 201.0 4.7 2.56

200 221.8 6.9 2.60

1000 270.0 19.8 2.73

Table 6-7 Present Day Scenario Design Discharge Events and Associated Total Coastal Water Levels

6.1.5 Future Scenario

To derive joint probability input boundaries for the future scenario models, peak discharges for each of the design events were taken from the Lower Dodder Future Scenario hydraulic models at Waldron’s Bridge. These design events were then matched with the total coastal water levels from Table 6-7 + 500mm (see Section 3.5.2 of the Hydrological Analysis Report). The Future Scenario design discharge events and the associated total coastal water levels which will be used in the hydraulic models are presented in Table 6-8 and Table 6-9.


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Future SUDS


(Years)


Bridge (m3/s)


(mOD)

2 132.40 2.92

5 154.47 2.94

10 184.52 2.94

25 220.40 2.98

50 246.19 3.01

100 291.55 3.06

200 336.70 3.1

1000 466.60 3.23

Table 6-8 Future SUDS Scenario Design Discharge Events and Associated Total Coastal Water Levels

Future No SUDS Design Event Return Period

(Years)


Bridge (m3/s)


(mOD)

2 125.27 2.92

5 148.84 2.94

10 174.13 2.94

25 211.67 2.98

50 236.61 3.01

100 281.87 3.06

200 322.17 3.1

1000 440.16 3.23

Table 6-9 Future No SUDS Scenario Design Discharge Events and Associated Total Coastal Water Levels


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6.2 DERIVATION OF EXTREME TOTAL COASTAL WATER LEVELS AND JOINT PROBABILITY FLUVIAL DISCHARGES

The methodology sequence used for the derivation of the fluvial discharges associated with extreme total coastal water levels is presented as a flow chart in Figure 6-6.

Figure 6-6 Methodology Sequence

6.2.1 Relationship between Total Water Levels and Tidal Surge

The design total coastal water levels used for this study have been taken from the Irish Coastal Protection Strategy Study and are presented in Table 6-10.


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Period (Years)


(mOD)

2 2.46

5 2.58

10 2.67

20 2.76

50 2.88

100 2.97

200 3.07

1000 3.28

Table 6-10 Design Event Total Coastal Water Levels

The joint probability surge residuals associated with a 1 in 0.05 year astronomical tide have been taken from Table 6-4 in Section 6.1.3 of this report and are present here in Table 6-11.


Period (Years)


(mOD)

Surge Residual

Levels (m)

2 2.46 0.42

5 2.58 0.54

10 2.67 0.63

20 2.76 0.74

50 2.88 0.84

100 2.97 0.93

200 3.07 1.02

1000 3.28 1.24

Table 6-11 Design Event Total Coastal Water Levels & Surge Residuals

6.2.2 Rainfall and Tidal Surge Joint Probability Analysis

Using Table 6-1 and Figure 6-4 in Section 6.1.1 and the surge residual levels from Table 6-11, the joint probability daily rainfall values associated with the surge levels were estimated. The surge residual levels and the associated daily rainfall totals are presented in Table 6-12.


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Joint Probability


Surge Residual

Levels (m) Daily Rainfall

(mm)

2 0.42 29

5 0.54 36

10 0.63 40

20 0.74 47

50 0.84 46

100 0.93 46

200 1.02 46

1000 1.24 42

Table 6-12 Joint Probability Surge Levels and Daily Rainfall Totals

6.2.3 Relationship between Fluvial Discharge and Rainfall

A trendline equation was developed in Section 6.1.2 to relate rainfall to fluvial discharge in the River Dodder Catchment at Waldron’s Bridge. The equation developed was y = 2.06x + 9.11 or in words “Discharge = 2.06 x Rainfall + 9.11”. The equation was applied to the daily rainfall totals in Table 6-12 to produce associated fluvial discharge values and the results are presented in Table 6-13.


Daily Rainfall (mm)


Bridge (m3/s)

2 29 68.9

5 36 83.3

10 40 91.5

20 47 105.9

50 46 103.9

100 46 103.9

200 46 103.9

1000 42 95.6

Table 6-13 Daily Rainfall Totals and Associated Fluvial Discharges

6.2.4 Design Event Extreme Total Coastal Water Levels and Fluvial Discharges

Table 6-14 presents the design event total coastal water levels (taken from Table 6-10) and the associated fluvial discharge which will be used as input boundaries in the Lower Dodder hydraulic models.


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(Years)


(mOD)


Bridge (m3/s)

2 2.46 68.9

5 2.58 83.3

10 2.67 91.5

20 2.76 105.9

50 2.88 103.9

100 2.97 103.9

200 3.07 103.9

1000 3.28 95.6

Table 6-14 Design Event Total Coastal Water Level and Associated Fluvial Discharge

It can be seen in Table 6-14 that for return periods greater than 20 year, the discharge at Waldron’s Bridge reduces. The reason for this is related to the joint probability curves in Figure 6-4 where a probability can be associated with a range of rainfall and surge level combinations. The particular total coastal water levels chosen for use in this study happen to correspond to discharges that are not monotonically increasing.


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7 HYDROGRAPH CONVOLUTION

As part of the Hydrological Analysis Report prepared for the River Dodder CFRAMS, design event peak discharges were calculated for 14 ‘sub-catchment’ rainfall-runoff models for Present Day and Future Scenarios. To create representative input boundary files for use in the 1-D hydraulic models, the linear reservoir equation was used to describe the peak discharge hydrograph shape for each sub-catchment.

The Linear Reservoir Equation can be written as:

u = t/k^2 * e^(-t/k)

Equation 7-1 Linear Reservoir Equation

Where:

u = Discharge (m3/s)

t = Time Step (mins.)

k = Time to Peak (mins.)

A hydrograph relating to a particular peak discharge can then be calculated using the following equation:

Qt = (Qpeak /umax)* ut

Equation 7-2 Hydrograph Equation

Where:

Qt = Discharge at each time step (m3/s)

Qpeak = Peak discharge for a given event (m3/s)

umax = Maximum u value from all time steps

ut = u calculated at each time step

Hydrograph details for each of the 14 Present Day ‘sub-catchment’ rainfall-runoff model catchments are presented in the following sections. Details for the Future Scenario catchment hydrographs are provided in Appendix B.

7.1 TRIBUTARY HYDROGRAPHS

The Time to Peak is assumed to be equal to the Time of Concentration for the ‘sub-catchment’ rainfall-runoff models contributing to the tributary streams as they have small catchment areas. The time of concentration for each catchment has been calculated using the Kirpich Equation as follows:

Equation 7-3 Kirpich Time of Concentration Equation

⎥⎦

⎤⎢⎣

⎡= 385.0

77.0

01947.0SLT


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Where

T = Time of Concentration (mins)

L = Catchment Length (m)

S = Catchment Slope (m/m)

7.1.1 Tallaght NAM Present Day

Time Step (t) = 0.25 mins.

Time of Concentration (k) = 29.1 mins.

Figure 7-1 presents the Tallaght NAM hydrographs for each of the Present Day design event flows.

Figure 7-1 Tallaght NAM Present Day Design Event Hydrographs

7.1.2 Owendoher NAM Present Day



Figure 7-2 presents the Owendoher NAM hydrographs for each of the Present Day design event flows.


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Figure 7-2 Owendoher NAM Present Day Design Event Hydrographs

7.1.3 Whitechurch NAM Present Day



Figure 7-3 presents the Whitechurch NAM hydrographs for each of the Present Day design event flows.

Figure 7-3 Whitechurch NAM Present Day Design Event Hydrographs


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7.1.4 Little Dargle NAM Present Day



Figure 7-4 presents the Little Dargle NAM hydrographs for each of the Present Day design event flows.

Figure 7-4 Little Dargle NAM Present Day Design Event Hydrographs

7.1.5 Dundrum NAM Present Day



Figure 7-5 presents the Dundrum NAM hydrographs for each of the Present Day design event flows.


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Figure 7-5 Dundrum NAM Present Day Design Event Hydrographs

7.1.6 Tallaght URBAN Present Day



Figure 7-6 presents the Tallaght Urban hydrographs for each of the Present Day design event flows.


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Figure 7-6 Tallaght Urban Present Day Design Event Hydrographs

7.1.7 Owendoher Whitechurch URBAN Present Day



Figure 7-7 presents the Owendoher Whitechurch Urban hydrographs for each of the Present Day design event flows.

Figure 7-7 Owendoher Whitechurch Urban Present Day Design Event Hydrographs


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7.1.8 Little Dargle URBAN Present Day



Figure 7-8 presents the Little Dargle Urban hydrographs for each of the Present Day design event flows.

Figure 7-8 Little Dargle Urban Present Day Design Event Hydrographs

7.1.9 Dundrum URBAN 1+2 Present Day



Figure 7-9 presents the Dundrum Urban 1+2 hydrographs for each of the Present Day design event flows.


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Figure 7-9 Dundrum Urban 1+2 Present Day Design Event Hydrographs

7.2 DODDER MAIN CHANNEL HYDROGRAPHS

The time of concentration for the hydrographs contributing to the River Dodder Main Channel hydraulic models were initially calculated using the Kirpich equation as per the tributary hydrographs. However, when these hydrographs were run through the hydraulic models, the flood outline produced did not compare well against the documented Hurricane Charlie floodplain. From further examination it was deduced that the volumes of the hydrographs were insufficient to cause the expected extent of flooding in the river catchment. Therefore, to ascertain an appropriate time of concentration for the Dodder River Main Channel an analysis was undertaken on the simulated discharge file produced using historic recorded rainfall from Waldron’s Bridge catchment (see Section 5.4.1 of Dodder CFRMP Hydrological Analysis Report).

The simulated discharge file was produced using 43 years of recorded rainfall (1963 to 2006) and the hydrographs from every discharge event greater than 0.7m3/s were extracted for this analysis. The time taken from the start of the hydrograph to the peak discharge was calculated for each event and the results examined. Table 7-1 presents a summary of the number of events in particular duration bands.


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Duration (Hrs.)

No. Events % of Events

> 100 1 0.04% 50 - 100 9 0.39% 40 - 50 18 0.79% 30 - 40 33 1.45% 20 - 30 97 4.25% 10 - 20 298 13.05% 5 - 10 608 26.63% 4 - 5 515 22.56% 3 - 4 465 20.37% 2 - 3 188 8.23% 1 - 2 42 1.84% < 1 9 0.39%

Total 2283 100.00%

Table 7-1 Summary Table of Time to Peak Durations from Historic Record at Waldron’s Bridge Gauge.

Table 7-1 shows that there is a large spread of durations, with the largest being greater than 100 hours and the smallest being less than 1 hour. The longer duration events may actually be combined events with an insufficient recession between them to register as individual events. In addition the attenuation effect of the Bohernabreena Reservoir system results in longer duration hydrographs than would otherwise be expected. Approximately 93% of the hydrograph time to peak durations are less than 20 hours and approximately 70% are between 3 and 10 hours. The aim of this analysis is therefore to produce a hydrograph at Waldron’s Bridge in the hydraulic models with a time to peak duration of between 3 and 10 hours.

In order to increase the time to peak duration and the volume of the hydrograph at Waldron’s Bridge, the time step and time of concentration were doubled for the hydrographs feeding the River Dodder Main Channel, i.e. Bohernabreena NAM, Dodder MC NAM, Dodder Urban 1, Dodder Urban 2 and Dodder Urban 3+4. When these “expanded” hydrographs were inputted into the hydraulic model in conjunction with the tributary hydrographs, a hydrograph with a time to peak duration of approximately 4 hours was produced at Waldron’s Bridge. The flood outline produced for extreme flood events using this “expanded” hydrograph produced results that compared well with the Hurricane Charlie flood outline which gave further confidence to the analysis.

The typical flow peak observed in the main Dodder Catchment for extreme storm events appears to have a time to peak in the order of twice the concentration time. It should be noted that the Flood Studies Report proposes a rainfall duration based on the Standard Annual Average Rainfall using the following equation: Duration = (1 + SAAR/1000) x Tp.

In relation to Waldron’s Bridge with a SAAR of 1100mm this would give a multiplier of 2.1 for the duration of the design storm in relation to the time of concentration and Tp. Depending on the storm profile this could also lead to a slightly longer lag time of the hydrograph. In addition the reservoir adds lag to the hydrograph, although the exact contribution is not known and is dependent on the available volume in the reservoir at the time of the event. In contrast this does not seem as pronounce with the tributaries, which is possibly due to smaller SAAR and higher degree of urbanisation. However it has to be stated that the process is not fully understood, though the output appears reasonable in relation to the observed runoff characteristics.

The following sections provide details of the present day hydrographs used in the hydraulic models for the River Dodder Main Channel.


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7.2.1 Bohernabreena NAM Present Day


Time Step x 2 = 0.50 mins.

Time of Concentration (k) (from Kirpich Equation) = 75 mins.

Time of Concentration x 2 = 150 mins

Figure 7-10 presents the Bohernabreena NAM hydrographs for each of the Present Day design event flows.

Figure 7-10 Bohernabreena NAM Present Day Design Event Hydrographs

7.2.2 Dodder Main Channel NAM Present Day



Time of Concentration (k) (from Kirpich Equation) = 65.7 mins.

Time of Concentration x 2 = 131.4 mins

Figure 7-11 presents the Dodder Main Channel NAM hydrographs for each of the Present Day design event flows.


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Figure 7-11 Dodder Main Channel NAM Present Day Design Event Hydrographs

7.2.3 Dodder URBAN 1 Present Day



Time of Concentration (k) (from Kirpich Equation) = 45 mins.

Time of Concentration x 2 = 90 mins.

Figure 7-12 presents the Dodder Urban 1 hydrographs for each of the Present Day design event flows.


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Figure 7-12 Dodder Urban 1 Present Day Design Event Hydrographs

7.2.4 Dodder URBAN 2 Present Day




Time of Concentration x 2 = 217.2 mins.

Figure 7-13 presents the Dodder Urban 2 hydrographs for each of the Present Day design event flows.


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Figure 7-13 Dodder Urban 2 Present Day Design Event Hydrographs

7.2.5 Dodder URBAN 3+4 Present Day




Time of Concentration x 2 = 274.8 mins.

Figure 7-14 presents the Dodder Urban 3+4 hydrographs for each of the Present Day design event flows.


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Figure 7-14 Dodder Urban 3+4 Present Day Design Event Hydrographs


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8 FLOOD MAPPING

Flood maps have been prepared for the River Dodder Main Channel and each of the five major tributaries. Guidance on the format of these flood maps has been provided by the Office of Public Works (OPW) from their work on the River Lee CFRAMS and is described in brief below.

• The Present Day Scenario 10%, 1% and 0.1% AEP flood outlines are to be mapped for each river. The three probability outlines are to be shown on the same drawing and identified using a set colour palette of dark to light blue.

• The centre line of the river is to be shown as a solid blue line.

• The background for the flood maps is to be Ordnance Survey 1:5000 mapping in greyscale.

• Nodes are to be identified with solid yellow circles and labelled. Flow and water level details for each node are to be presented in tabular format on the drawing.

An example flood map is presented in Figure 8-1.

Figure 8-1 Example Flood Map

A full set of flood maps for each of the rivers prepared according to the prescribed format is presented in a separate Flood Mapping Report.

Tabulated results of the Dodder hydraulic model and tributaries for the 2, 5, 10, 25, 50, 100, 200 and 1000 year return periods and corresponding profile plots are presented in Appendix D.


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8.1 FLOOD MAPPING METHODOLOGY

The flood outlines for the Dodder Upper, Dodder Middle, Dodder Lower, Tallaght Stream, Owendoher Stream, Whitechurch Stream and Dundrum / Slang Stream have been taken directly from the MIKE coupled hydraulic models. The 2-D model results have been converted into ArcGIS shapefiles using a special conversion tool which streamlines the mapping process.

8.1.1 1-D Flood Mapping Methodology

The Little Dargle Stream flood maps have been created from 1-D hydraulic model outputs. The methodology employed in this task is described as follows:

• The river centreline was plotted in ArcGIS using x and y coordinate points taken from the MIKE 11 model.

• 30 No. cross-section chainage points and associated maximum water levels were taken from the MIKE 11 model and these points were plotted on the river centreline in ArcGIS.

• The AutoCAD topographical survey drawing produced for the Little Dargle Stream was converted into a point shapefile in ArcGIS and the cross-section locations identified.

• Flood outlines were sketched in ArcGIS by drawing polylines between points from the topographical survey with the same level as the maximum water level at the cross-sections. The polylines were then converted to polygons.

• This process was repeated for each AEP event.

8.2 FLOOD MECHANISMS

It is important to identify the mechanisms of flooding or the causes of flood waters leaving the river channel for each flood location to facilitate the development of flood alleviation options. The flood mechanisms are discussed for each river model in the following sections and the chainages marked on the flood maps in the separate Flood Mapping Report are used for reference purposes.

8.2.1 Upper Dodder

The upper reaches of the River Dodder are predominantly rural and the river banks have been retained in their natural state. The main mechanism of flooding along this reach is water exiting the river channel through low points in the river banks. The water then fills the natural river valley and causes little or no flooding to property. The flooding locations and associated flood mechanisms are listed in Table 8-1.


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Upper Dodder Flood Mechanisms

Flood Ref. River Model Map Ref. Location Bank Flood

Mechanism Flood Event

Nature of Flooded

Area

1 Upper Dodder Dodder - 1 of 12

UDS1-1553 to UDS1-2450 Left & Right Low River

Banks 1% & 0.1%

AEP Rural


UDS1-3350 to UDS1-3450 Left Low River

Banks 1% & 0.1%

AEP Rural



Banks 1% & 0.1%

AEP Rural

4 Upper Dodder Dodder - 2 of 12 UDS1-4450 Left Low River

Banks 1% & 0.1%

AEP Rural


UDS1-4650 to UDS1-4750 Left & Right

Low River Bank &

Downstream Weir

1% & 0.1% AEP Rural



Banks 1% & 0.1%

AEP Rural

Table 8-1 Flood Locations and Mechanisms from Upper Dodder Model

8.2.2 Middle Dodder

The middle reaches of the Dodder, stretching from approximately Firhouse weir to Rathfarnham Road Bridge, flows through both parkland and urbanised areas. Flooding along this stretch of river can be attributed in the main to low river banks /overtopping of existing defences or insufficient channel / floodplain capacity. In addition there are two large weirs along this stretch which produce elevated upstream water levels, reducing freeboard through this area and resulting in some flooding in extreme events. The flooding locations and associated flood mechanisms are listed in Table 8-2.


MDW0259Rp0021 113 Rev F01

Middle Dodder Flood Mechanisms

Flood Ref.

River Model Map Ref. Location Bank Flood Mechanism Flood

Event Nature of Flooded

Area

1 Middle Dodder

Dodder - 3 of 12

MDS1-6750 to MDS1-7149 Left & Right Low River Bank &

Weir 1% & 0.1%

AEP Parkland

2 Middle Dodder

Dodder - 3 of 12 & 4 of 12

MDS1-7550 to MDS1-8156 Left & Right Low River Banks 1% & 0.1%

AEP Parkland

3 Middle Dodder

Dodder - 4 of 12 & 5 of 12

MDS1-8250 to MDS1-9145 Left & Right

Low River Banks & Downstream Weir. Flooding of the left bank urban area is caused by water exiting the river

between MDS1-8451 and MDS1-8577.

Flooding of the right bank urban area is caused by water exiting the river

between MDS1-8949 and MDS1-9051

1% & 0.1% AEP

Parkland / Urban

4 Middle Dodder

Dodder - 5 of 12


AEP Parkland

5 Middle Dodder

Dodder - 5 of 12


AEP Parkland

6 Middle Dodder

Dodder - 5 of 12 & 6 of 12

MDS1-10450 to MDS1-11051 Left Low River Bank 1% & 0.1%

AEP Parkland

7 Middle Dodder

Dodder - 6 of 12

MDS1-10936 to MDS1-11250 Right

Low River Bank - water exits river at

approx. MDS1-10936 and floods

surrounding area.

1% & 0.1% AEP

Parkland / Urban

8 Middle Dodder

Dodder - 6 of 12

MDS1-11351 to MDS1-11670 Left Low River Bank 1% & 0.1%

AEP Parkland

9 Middle Dodder

Dodder - 4 of 12

Firhouse Weir (U/S M50 Bridge) - Weir - Raised water

levels 10%, 1% & 0.1% AEP Parkland

10 Middle Dodder

Dodder - 5 of 12 D/S Old Bridge Road - Weir - Raised water

levels 10%, 1% & 0.1% AEP Parkland

Table 8-2 Flood Locations and Mechanisms from Middle Dodder Model

8.2.3 Lower Dodder – Fluvial Scenario

The lower reaches of the River Dodder, stretching from Rathfarnham Road Bridge to the confluence with the River Liffey, flows through a highly urbanised area. As before, flooding along this stretch of river can be attributed in the main to low river banks / overtopping of existing defences or insufficient channel / floodplain capacity. Throughout this stretch, there is urban development adjacent to the river channel, with few green floodplain areas remaining. As a result, there is a large amount of property damage realised during flood events.

There are also a series of large weirs along this stretch of river which serve to artificially raise upstream water levels. These high water levels reduce the available freeboard and locally increase flood risk. In addition a number of bridges along this stretch appear to have insufficient conveyance capacity for extreme flood events. The undersized bridges cause water to back-up producing elevated water level upstream. The flooding locations and associated flood mechanisms are listed in Table 8-3.


MDW0259Rp0021 114 Rev F01

Lower Dodder Flood Mechanisms (Fluvial Scenario)

Flood Ref.


Event Nature of

Flooded Area

1 Lower

Dodder - Fluvial

Dodder - 6 of 12

LD1-11700 to LD1-11801

Left & Right

Low river bank / existing defences overtopped & downstream weir. Water

exits the left bank at LD1-11700 and flows over

Rathfarnham Road bridge causing extensive flooding of Dodder Park Road and Dodder Road Lower in the

0.1% AEP event.

1% & 0.1% AEP Urban

2 Lower

Dodder - Fluvial

Dodder - 6 of 12

LD1-11810 to LD1-11991

Left & Right

Low river bank / existing defences overtopped &

downstream weir.

1% & 0.1% AEP Urban

3 Lower

Dodder - Fluvial

Dodder - 6 of 12 & 7 of 12

LD1-12191 to LD1-13090

Left & Right

Low river bank / existing defences overtopped & downstream weir. Flood

water flowing through Orwell Park flow over

Orwell Road.

10%, 1% & 0.1% AEP

Parkland / Urban

4 Lower

Dodder - Fluvial

Dodder - 7 of 12 LD1-13094 Left &

Right


exits the right bank at LD1-13094 causing extensive flooding in

Orwell Gardens.

1% & 0.1% AEP Urban

5 Lower

Dodder - Fluvial

Dodder - 7 of 12

LD1-13297 to LD1-13420 Right Low river bank / existing

defences overtopped. 10%, 1% & 0.1% AEP Urban

6 Lower

Dodder - Fluvial

Dodder - 7 of 12

LD1-13420 to LD1-13799 Left


downstream weir.

10%, 1% & 0.1% AEP

Parkland / Urban

7 Lower

Dodder - Fluvial

Dodder - 7 of 12

LD1-13514 to LD1-13900 Right


downstream weir.

10%, 1% & 0.1% AEP

Parkland / Urban

8 Lower

Dodder - Fluvial

Dodder - 7 of 12

LD1-13900 to LD1-14340

Left & Right

Low river bank / existing defences overtopped.

Water exiting the left bank continues to flow down

Milltown Road underneath the viaduct beyond LD1-

14340

10%, 1% & 0.1% AEP

Parkland / Urban

9 Lower

Dodder - Fluvial

Dodder - 7 of 12

LD1-14500 to LD1-14689

Left & Right


downstream weir.

1% & 0.1% AEP Urban

10 Lower

Dodder - Fluvial

Dodder - 8 of 12

LD1-14930 to LD1-15200 Right


downstream weir.

1% & 0.1% AEP Urban

11 Lower

Dodder - Fluvial

Dodder - 8 of 12

LD1-14850 to LD1-15402 Left

Low river bank / existing defences overtopped & downstream weir. Water exiting the left bank flows over Clonskeagh Road,

flooding the old paper mill site. Flooding on the right bank is caused by water

crossing Clonskeagh Road bridge from the left

bank.

10%, 1% & 0.1% AEP Urban

12 Lower

Dodder - Fluvial

Dodder - 8 of 12

LD1-15850 to LD1-16000 Left


exiting the left bank continues to flow along left bank beyond LD1-16000

10%, 1% & 0.1% AEP Urban


MDW0259Rp0021 115 Rev F01


Flood Ref.


Event Nature of

Flooded Area

13 Lower

Dodder - Fluvial

Dodder - 8 of 12 & 9 of 12

LD1-16298 to LD1-16901 Left


Capacity of downstream bridge insufficient. Water exiting the channel along this stretch continues to flow along the left bank

beyond LD1-16901 causing extensive flooding

to Donnybrook rugby grounds and Herbert Park. The flood waters then flow

in a northerly direction across Clyde Lane, Clyde

Road, Elgin Road, Pembroke Road, along Shelbourne Road and

across the DART line at Bath Avenue, flooding the

Ringsend area. Water exiting the left bank also flows across Donnybrook

Road bridge causing flooding to the Bus Aras site on the right bank. In addition flooding waters

cross from the left bank at Herbert Hotel to the RDS on the right bank and at

Ballbridge to Beatty's Avenue on the right bank.

1% & 0.1% AEP Urban

14 Lower

Dodder - Fluvial

Dodder - 9 of 12 LD1-16901 Right Low river bank / existing

defences overtopped. 1% & 0.1%

AEP Parkland /

Urban

15 Lower

Dodder - Fluvial

Dodder - 9 of 12 & 10 of 12

LD1-17801 to LD1-18299 Right


Capacity of downstream bridge insufficient. Flood waters travel along the right bank in a northerly

direction along Sepentine Avenue, Tritonville Road,

Irishtown Road and across to Sandymount

Road causing extensive flooding to the

Sandymount / Ringsend area.

1% & 0.1% AEP Urban

16 Lower

Dodder - Fluvial

Dodder - 9 of 12 Ballsbridge - Bridge - Insufficient flow

capacity 1% & 0.1%

AEP Urban

17 Lower

Dodder - Fluvial

Dodder - 10 of 12 DART Bridge - Bridge - Insufficient flow

capacity 10%, 1% & 0.1% AEP Urban

18 Lower

Dodder - Fluvial

Dodder - 10 of 12 New Bridge - Bridge - Insufficient flow


19 Lower

Dodder - Fluvial

Dodder - 10 of 12

Londonbridge Road - Bridge - Insufficient flow


20 Lower

Dodder - Fluvial

Dodder - 6 of 12

D/S Rathfarnham Road Bridge

- Weir - Raised water levels 10%, 1% & 0.1% AEP Urban

21 Lower

Dodder - Fluvial

Dodder - 7 of 12

Orwell Weir (D/S Orwell Road

Bridge - Weir - Raised water levels 10%, 1% &

0.1% AEP Urban


MDW0259Rp0021 116 Rev F01


Flood Ref.


Event Nature of

Flooded Area

22 Lower

Dodder - Fluvial

Dodder - 7 of 12

Adjacent Milltown Road

(U/S Churchtown Road Lower

Bridge)


23 Lower

Dodder - Fluvial

Dodder - 8 of 12

Adjacent Shanagarry Apartment

Development


24 Lower

Dodder - Fluvial

Dodder - 8 of 12

D/S Clonskeagh Road Bridge - Weir - Raised water levels 10%, 1% &

0.1% AEP Urban

25 Lower

Dodder - Fluvial

Dodder - 8 of 12

Adjacent Beaver Row (U/S

Anglesea Road Bridge)


Table 8-3 Flood Locations and Mechanisms from Lower Dodder Model – Fluvial Scenario

8.2.4 Lower Dodder – Tidal Scenario

The tidal section of the River Dodder stretches from below the weir at Ballsbridge, to the confluence with the River Liffey, a length of approximately 2km. This portion of the catchment is highly urbanised. Tidal flooding in the Lower Dodder can be attributed entirely to overtopping of existing defences. The flooding locations and associated flood mechanisms are listed in Table 8-4

Lower Dodder Flood Mechanisms (Tidal)

Flood Ref. River Model Map Ref. Location Bank Flood Mechanism Flood Event

Nature of Flooded

Area

1 Lower Dodder - Tidal

Dodder (Tidal) - 1 of 2 LD1-19594 Right Low river bank / existing

defences overtopped. 0.5% & 0.1%

AEP Urban



defences overtopped. 0.5% & 0.1%

AEP Urban



defences overtopped. 0.1% AEP Urban

Table 8-4 Flood Locations and Mechanisms from Lower Dodder Model – Tidal Scenario


The Tallaght Stream tributary of the River Dodder flows through a highly urbanised suburb of Dublin City. However a significantly wide riparian strip has been maintained along the stream reducing potential property damage during flood events. Flooding along this stream can be attributed to a combination of insufficient channel capacity and insufficient bridge / culvert conveyance capacity. The flooding locations and associated flood mechanisms are listed in Table 8-5.


MDW0259Rp0021 117 Rev F01

Tallaght Stream Flood Mechanisms

Flood Ref.



Area

1 Tallaght Stream

Tallaght - 1 of 3 TS1-710 Left & Right Insufficient channel

capacity 1% & 0.1%

AEP Parkland /

Urban

2 Tallaght Stream

Tallaght - 1 of 3 TS1-1390 Left & Right Capacity of bridge

opening insufficient 0.1% AEP Parkland / Urban

3 Tallaght Stream

Tallaght - 2 of 3 TS1-2081 Left & Right

Capacity of bridge opening insufficient & low bank level.

1% & 0.1% AEP

Parkland / Urban

4 Tallaght Stream

Tallaght - 2 of 3 TS1-2312 Left & Right Insufficient channel

capacity 1% & 0.1%

AEP Parkland /

Urban

5 Tallaght Stream

Tallaght - 2 of 3 TS1-2494 Left & Right

Capacity of bridge opening insufficient & downstream weirs raise water levels.

1% & 0.1% AEP

Parkland / Urban

6 Tallaght Stream

Tallaght - 2 of 3

TS1-2958 to TS1-3210 Right

Low pond bank level & insufficient

capacity of bridge opening (Old Bawn

Road).

1% & 0.1% AEP

Parkland / Urban

7 Tallaght Stream

Tallaght - 3 of 3

TS1-3431 to TS1-4633 Left & Right Insufficient channel

capacity 0.1% AEP Parkland / Urban

8 Tallaght Stream

Tallaght - 1 of 3

TS1-1401 (Blessington

Road) - Bridge - Insufficient

flow capacity 10%, 1% & 0.1% AEP

Parkland / Urban

9 Tallaght Stream

Tallaght - 1 of 3

TS1-1401 (Killinarden

Heights Bridge 1)

- Bridge - Insufficient flow capacity 0.1% AEP Parkland /

Urban

10 Tallaght Stream

Tallaght - 1 of 3

TS1-1445 (Killinarden

Heights Bridge 2)

- Bridge - Insufficient flow capacity 0.1% AEP Parkland /

Urban

11 Tallaght Stream

Tallaght - 2 of 3

TS1-2104 (Kiltipper Way) - Bridge - Insufficient

flow capacity 1% & 0.1%

AEP Parkland /

Urban

12 Tallaght Stream

Tallaght - 2 of 3

TS1-2495 (Dun An Oir) - Bridge - Insufficient


Parkland / Urban

13 Tallaght Stream

Tallaght - 2 of 4

TS1-3049 (Sean Walsh Memorial

Park) - Bridge - Insufficient

flow capacity 10%, 1% & 0.1% AEP Parkland

14 Tallaght Stream

Tallaght - 2 of 3

TS1-3138 (Old Bawn Road) - Bridge - Insufficient


Parkland / Urban

15 Tallaght Stream

Tallaght - 3 of 3

TS1-4540 (Avonmore

Road) - Bridge - Insufficient

flow capacity 1% & 0.1%

AEP Parkland /

Urban

16 Tallaght Stream

Tallaght - 2 of 3

TS1-2543 (Downstream Dun An Oir)

- Weir - Raised water levels

10%, 1% & 0.1% AEP

Parkland / Urban

Table 8-5 Flood Locations and Mechanisms from Tallaght Stream Model


The Owendoher Stream tributary of the River Dodder flows through a highly urbanised section of the catchment. Flooding along this stream only occurs during extreme conditions (0.1% AEP) and can be attributed to low stream banks or insufficient channel / floodplain capacity. In addition, there is insufficient conveyance capacity at two bridge / culvert structures causing water to back-up producing elevated upstream water levels. There are also a number of weir structures along this stream which locally increase upstream water levels, reducing available freeboard and increasing flood risk. The flooding locations and associated flood mechanisms are listed in Table 8-6.


MDW0259Rp0021 118 Rev F01

Owendoher Flood Mechanisms

Flood Ref.



Area

1 Owendoher Stream

Owendoher & Whitechurch -

2 of 3

OS1-1342 to OS1-2648 Left & Right


Downstream weirs produce locally elevated

water levels. Water leaves channel at OS1-1342 and travels down

Ballyboden Road causing flooding to

OS1-2648

0.1% AEP Parkland / Urban

2 Owendoher Stream


3 of 3

OS1-3160 to OS1-3650 Left & Right

Exisitng defences overtopped. Capacity of

bridge openings insufficient. Water

leaves channel at OS1-3160 and travels down Willbrook Road causing flooding to OS1-3650

0.1% AEP Urban

Table 8-6 Flood Locations and Mechanisms from Owendoher Stream Model


The Whitechurch Stream tributary of the Owendoher Stream flows through both parkland and urbanised areas. The stream is heavily modified with a large number of bridges / culverts and weirs. Flooding along this stretch of river can be attributed in the main to low stream banks / overtopping of existing defences or insufficient channel / floodplain capacity. In addition, there is insufficient conveyance capacity at a large number of bridge / culvert structures causing water to back-up producing elevated upstream water levels. There are also two large weir structures along the stream which locally increase upstream water levels, reducing available freeboard and increasing flood risk. The flooding locations and associated flood m are listed in Table 8-7.

Whitechurch Flood Mechanisms

Flood Ref.


Event

Nature of Flooded

Area

1 Whitechurch Stream


1 of 3

WS1-539 to WS1-849

Left & Right

Low stream banks / exisitng defences

overtopped. Capacity of bridge / culvert

insufficient. Water leaves channel at WS1-

641 causing flooding from WS1-539 to WS1-

849

10%, 1% & 0.1% AEP Rural



1 of 3 WS1-849 Left &

Right

Low stream banks / exisitng defences

overtopped. Capacity of bridge / culvert

insufficient.

10%, 1% & 0.1% AEP Rural


Owendoher & Whitechurch - 1 of 3 & 2 of

3

WS1-849 to WS1-1571

Left & Right

Low stream banks / existing defences

overtopped. Insufficient channel capacity. Flood

waters travel over floodplain causing

flooding downstream.

10%, 1% & 0.1% AEP Rural


MDW0259Rp0021 119 Rev F01


Flood Ref.



Area



2 of 3

WS1-1870 to WS1-2083

Left & Right


overtopped. Insufficient channel capacity.

Downstream weir raises water levels. Flood waters travel over floodplain causing


10%, 1% & 0.1% AEP

Parkland (St. Enda's

Park)



2 of 3

WS1-2471 to WS1-2561

Left & Right



Downstream weir raises water levels. Flood waters travel over floodplain causing


1% & 0.1% AEP Urban



2 of 3

WS1-2561 to WS1-2676

Left & Right


overtopped. Insufficient channel capacity. Flood

waters travels along Whitechurch Road causing flooding

downstream.

1% & 0.1% AEP Urban



2 of 3 WS1-2866 Left &

Right



Capacity of downstream bridge / culvert

insufficient. Flood waters travel along Whitechurch

Road and across floodplain causing


1% & 0.1% AEP Urban



2 of 3

WS1-2940 to WS1-3060 Right


overtopped. Insufficient channel capacity. Weir

raises water levels. Flood waters travel across floodplain causing flooding

downstream.

1% & 0.1% AEP Urban



3 of 3

WS1-3060 to WS1-3267

Left & Right



1% & 0.1% AEP Urban



1 of 3

WS1-650 (Whitechurch

National School)

- Bridge - Insufficient flow capacity

10%, 1% & 0.1% AEP Rural



1 of 3

WS1-820 (Edmonstown

Golf Club) - Bridge - Insufficient flow

capacity 0.1% AEP Rural



1 of 3

WS1-935 (Private Bridge)


10%, 1% & 0.1% AEP Rural



2 of 3

WS1-1922 (St. Enda's

Park) - Bridge - Insufficient flow

capacity 1% & 0.1%

AEP


Park)


MDW0259Rp0021 120 Rev F01


Flood Ref.



Area



2 of 3

WS1-2715 (St. Gatien

Court) - Bridge - Insufficient flow




2 of 3

WS1-2850 (Garage

forecourt) - Bridge - Insufficient flow

capacity 1% & 0.1%

AEP Urban



2 of 3

WS1-2915 (Garage

forecourt) - Bridge - Insufficient flow




3 of 3

WS1-2974 (Private Bridge)


1% & 0.1% AEP Urban



3 of 3

WS1-3098 (Willbrook

Lawn) - Bridge - Insufficient flow




3 of 3

WS1-3098 (Footbridge to

Willbrook Grove)


10%, 1% & 0.1% AEP Urban



2 of 3

WS1-2020 (St. Enda's

Park) - Weir - Raised water

levels 10%, 1% & 0.1% AEP


Park)



2 of 3

WS1-2585 (Whitechurch

Road) - Weir - Raised water

levels 10%, 1% & 0.1% AEP Urban



3 of 3 WS1-3040 - Weir - Raised water

levels 10%, 1% & 0.1% AEP Urban

Table 8-7 Flood Locations and Mechanisms from Whitechurch Stream Model

8.2.8 Little Dargle Stream

The Little Dargle assessment unit flows through both parkland and urbanised areas. A significant length of this stream is currently culverted and the remaining open channel sections have been provided with a wide riparian strip. For these reasons there is little flooding within the assessment unit. Flooding along this stretch of river can be attributed to low stream banks / overtopping of existing defences or insufficient channel / floodplain capacity. In addition, there is insufficient conveyance capacity at a number of bridge / culvert structures causing water to back-up producing elevated upstream water levels. There are also a number of weir structures along this length of stream which locally increase upstream water levels, reducing available freeboard and increasing flood risk. The flooding locations and associated flood mechanisms are listed in Table 8-8.


MDW0259Rp0021 121 Rev F01

Dundrum / Slang Flood Mechanisms

Flood Ref.



Area

1 Little Dargle Stream

Little Dargle - 1 of 3

LIS1-537 to LIS1-730

Left & Right



insufficient.

10%, 1% & 0.1% AEP Parkland


Little Dargle - 1 of 3 & 2

of 3

LIS1-975 to LIS1-1290

Left & Right



insufficient.




LIS1-1400 to LIS1-1690

Left & Right



insufficient.

1% & 0.1% AEP

Parkland / Urban



LIS1-1800 to LIS1-1901

Left & Right


Downstream weirs produce locally elevated

water levels.




LIS1-2020 to LIS1-2413

Left & Right





LIS1-2413 to LIS1-2640

Left & Right



insufficient.




LIS1-3759 to LIS1-4235

Left & Right



insufficient.

10%, 1% & 0.1% AEP

Parkland / Urban



LIS1-709 (Footbridge in Marley Park)





LIS1-733 (Grange Road) - Bridge - Insufficient flow




LIS1-1336 (Stone Mason's

Way) - Bridge - Insufficient flow




LIS1-2565 (Footbridge in


capacity 10%, 1% & 0.1% AEP Parkland



LIS1-2670 (Nutgrove Avenue)


10%, 1% & 0.1% AEP Urban



LIS1-4083 (Culvert to

River Dodder) - Bridge - Insufficient flow


Table 8-8 Flood Locations and Mechanisms from Little Dargle Stream Model


The Dundrum / Slang assessment unit flows through a highly urbanised area and is heavily modified with a large number of bridges / culverts, weirs and canalised sections. Flooding along this stretch of river can be attributed in the main to low stream banks / overtopping of existing defences or insufficient


MDW0259Rp0021 122 Rev F01

channel / floodplain capacity. In addition, there is insufficient conveyance capacity at a number of bridge / culvert structures causing water to back-up producing elevated upstream water levels. There are also a number of weir structures along this length of stream which locally increase upstream water levels, reducing available freeboard and increasing flood risk. The flooding locations and associated flood mechanisms are listed in Table 8-9.


Flood Ref. River Model Map Ref. Location Bank Flood Mechanism Flood

Event

Nature of

Flooded Area

1 Dundrum/Slang Stream

Dundrum Slang - 1 of 3

DSS2-98 to DSS2-250

Left & Right


overtopped. Insufficient channel

capacity.Capacity of downstream bridge / culvert insufficient. Flood waters travel

along Ballinteer Road causing flooding

downstream.

1% & 0.1% AEP

Urban


Dundrum Slang - 1 of 3 DSS2-544 Left &

Right



capacity.Capacity of downstream bridge / culvert insufficient. Flood waters travel

along Ballinteer Road and Ashlawn causing flooding downstream.

1% & 0.1% AEP

Urban



DSS2-750 to DSS1-960

Left & Right



capacity.Capacity of downstream bridge / culvert insufficient,

producing raised water levels through this area.

1% & 0.1% AEP

Urban



DSS1-1276 to DSS1-1480

Left & Right



capacity.Capacity of downstream bridge / culvert insufficient,

producing raised water levels through this area.

1% & 0.1% AEP

Urban



DSS1-405 to DSS2-750

Left & Right



0.1% AEP Urban


MDW0259Rp0021 123 Rev F01



Event

Nature of

Flooded Area



DSS1-2900 to DSS1-3244

Left & Right



capacity.Capacity of downstream bridges / culverts insufficient.

1% & 0.1% AEP

Urban



DSS1-3420 to DSS1-3720 Right




1% & 0.1% AEP

Urban



DSS1-3830 to DSS1-4010 Right




Downstream weir raises water levels.

0.1% AEP Urban



DSS1-4110 to DSS1-4390

Left & Right




0.1% AEP Urban



DSS1-518 (Pedestrian

Bridge) - Bridge - Insufficient flow

capacity

1% & 0.1% AEP

Urban



DSS1-720 (Ballinteer

Road) - Bridge - Insufficient flow

capacity

1% & 0.1% AEP

Urban



DSS2-370 (Off Ballinteer


capacity

1% & 0.1% AEP

Urban



DSS2-594 (Ballinteer


capacity 0.1% AEP Urban



DSS2-715 (New Bridge off Ballinteer

Road)


0.1% AEP Urban



DSS2-740 (New Bridge off Ballinteer

Road)


1% & 0.1% AEP

Urban



DSS1-1334 (Footbridge in


capacity

1% & 0.1% AEP

Urban



DSS1-1402 (Sandyford


capacity

1% & 0.1% AEP

Urban



DSS1-1517 (Pedestrian

Bridge) - Bridge - Insufficient flow

capacity

1% & 0.1% AEP

Urban


MDW0259Rp0021 124 Rev F01



Event

Nature of

Flooded Area



DSS1-1550 (Wyckham

Way) - Bridge - Insufficient flow

capacity

1% & 0.1% AEP

Urban



DSS1-1701 (Culvert

underneath Dundrum SC)


1% & 0.1% AEP

Urban



DSS1-2712 (Culvert at

Library) - Bridge - Insufficient flow

capacity

1% & 0.1% AEP

Urban



DSS1-2864 (Churchtown


capacity

1% & 0.1% AEP

Urban



DSS1-2938 (Industrial

Estate) - Bridge - Insufficient flow

capacity

10%, 1% & 0.1%

AEP Urban



DSS1-3184 (Frankfort


capacity

1% & 0.1% AEP

Urban



DSS1-3356 (Frankfort) - Bridge - Insufficient flow

capacity

1% & 0.1% AEP

Urban



DSS1-3794 (St.

Columbanus Road)


1% & 0.1% AEP

Urban



DSS1-4053 (Farrenboley) - Bridge - Insufficient flow

capacity 0.1% AEP Urban



DSS1-4527 (Culvert to

River Dodder) - Bridge - Insufficient flow

capacity

1% & 0.1% AEP

Urban


Dundrum Slang - 3 of 3 DSS1-4053 - Weir - Raised water

levels

10%, 1% & 0.1%

AEP Urban

Table 8-9 Flood Locations and Mechanisms from Dundrum / Slang Stream Model


MDW0259Rp0021 125 Rev F01

9 SUMMARY AND CONCLUSION

To summarise, the primary objective of this report was to describe the hydraulic analysis undertaken for the River Dodder CFRAMS. This was achieved through detailed documentation of the data collection, model construction, sensitivity analysis, design event and joint probability analysis, hydrograph convolution and flood mapping processes employed for this study.

Hydraulic models were constructed for the River Dodder main channel and each of its five major tributaries based on topographical survey and digital terrain model data. Discharge inputs to these hydraulic models were developed during the hydrological analysis stage of this study which is discussed fully in the Hydrological Analysis Report developed for the River Dodder CFRAMS. These discharges were subject to a joint probability analysis as part of the hydraulic analysis process and the resulting combination of flow inputs and water level boundaries were then applied to the hydraulic models as hydrographs, where appropriate. In addition, tide levels for the lower reaches of the River Dodder were derived as part of the hydraulic analysis and applied as downstream water level boundaries.

A thorough sensitivity analysis was undertaken on the hydraulic model parameters and future scenario model inputs. It was concluded from this analysis that the model parameters with the greatest influence are the 2-D model grid resolution and the peak discharge. In addition, it was noted that the topography of the floodplain plays a significant role in determining the severity of the impact of increased peak discharges.

Each of the hydraulic models were run for the 2 year (50% AEP), 5 year (20% AEP), 10 year (10% AEP), 25 year (4% AEP), 50 year (2% AEP), 100 year (1% AEP), 200 year (0.5% AEP) and 1000 year (0.1% AEP) return period design events for both Present Day and Future Scenario conditions. The flood outlines generated by these models and flood mechanisms identified were calibrated against historic data and anecdotal observations where information was available. Detailed flood maps presenting the results of the hydraulic analyses will be available in a separate Flood Mapping Report.

Given the robust hydraulic analysis undertaken for this study it is concluded that no further hydrodynamic modelling or analysis is required for the River Dodder Main Channel or the five major tributaries to satisfy the requirements of the project brief.

APPENDIX A

Digital Topographical Survey

APPENDIX B

Future Scenario Dependence Analysis Results


MDW0259Rp0021 B1 Rev F01

Future SUDS Scenario Dependence Analysis Results

The Rainfall Runoff Catchment locations for the Future SUDS scenario are the same as those for the Present Day scenario and are shown in Figure 5-5 in the report text.

B.1. Dodder Main Channel and Tallaght Stream


Tallaght Dodder Main Sum Tallaght Dodder Main Sum

8.346 0.000 8.346 10.617 0.000 10.617 8.346 11.192 19.538 10.617 13.905 24.522 8.346 22.385 30.731 10.617 27.811 38.428 8.262 33.577 41.839 10.510 41.716 52.226 7.573 44.770 52.343 9.634 55.622 65.256 7.081 49.433 56.515 9.008 61.416 70.424 6.049 55.962 62.011 7.695 69.527 77.222 5.311 59.693 65.004 6.756 74.162 80.919 3.541 66.689 70.229 4.504 82.853 87.357 3.288 67.155 70.443 4.182 83.433 87.615 1.770 69.553 71.324 2.252 86.412 88.664 0.000 69.953 69.953 0.000 86.909 86.909 Max 71.324 Max 88.664

Figure B 1 Future SUDS Dodder Main Channel and Tallaght Stream 2 and 5 Year Return Period



12.296 0.000 12.296 14.725 0.000 14.725 12.296 16.226 28.522 14.725 19.652 34.377 12.296 32.453 44.749 14.725 39.304 54.029 12.172 48.679 60.851 14.576 58.956 73.532 11.157 64.906 76.063 13.362 78.608 91.970 10.433 71.667 82.100 12.494 86.796 99.290 8.911 81.132 90.043 10.672 98.260 108.932 7.825 86.541 94.366 9.370 104.811 114.181 5.216 96.682 101.899 6.247 117.093 123.340 4.844 97.358 102.202 5.801 117.912 123.713 2.608 100.835 103.444 3.123 122.123 125.247 0.000 101.415 101.415 0.000 122.825 122.825 Max 103.444 Max 125.247





Tallaght Dodder Main Sum Tallaght Dodder Main Sum 16.792 0.000 16.792 19.106 0.000 19.106 16.792 22.622 39.414 19.106 25.998 45.104 16.792 45.244 62.036 19.106 51.995 71.101 16.622 67.866 84.489 18.913 77.993 96.906 15.237 90.488 105.726 17.337 103.990 121.327 14.248 99.914 114.162 16.211 114.823 131.034 12.170 113.110 125.280 13.847 129.988 143.835 10.686 120.651 131.337 12.158 138.654 150.812 7.124 134.790 141.914 8.106 154.902 163.008 6.615 135.732 142.348 7.527 155.986 163.512 3.562 140.580 144.142 4.053 161.557 165.609 0.000 141.388 141.388 0.000 162.485 162.485 Max 144.142 Max 165.609




21.707 0.000 21.707 29.094 0.000 29.094 21.707 29.851 51.558 29.094 41.093 70.187 21.707 59.702 81.409 29.094 82.186 111.280 21.488 89.553 111.040 28.800 123.278 152.079 19.697 119.404 139.101 26.400 164.371 190.771 18.418 131.841 150.259 24.686 181.493 206.179 15.732 149.254 164.986 21.086 205.464 226.550 13.814 159.205 173.018 18.514 219.162 237.676 9.209 177.861 187.071 12.343 244.845 257.188 8.551 179.105 187.657 11.461 246.557 258.018 4.605 185.502 190.106 6.171 255.362 261.534 0.000 186.568 186.568 0.000 256.830 256.830 Max 190.106 Max 261.534




B.2. Dodder Main Channel and Dodder Urban 1

2 Year Joint Probability 5 Year Joint Probability Dodder Urban

1 Dodder Main Sum Dodder Urban 1 Dodder Main Sum

3.530 0.000 3.530 4.680 0.000 4.680

3.530 12.639 16.169 4.680 15.853 20.533

3.530 25.279 28.809 4.680 31.706 36.386

3.530 37.918 41.448 4.680 47.558 52.238

3.462 50.558 54.020 4.590 63.411 68.002

2.757 63.197 65.954 3.655 79.264 82.919

1.880 72.045 73.925 2.492 90.361 92.853

1.462 75.837 77.299 1.938 95.117 97.055

0.000 84.399 84.399 0.000 105.856 105.856

Max 84.399 Max 105.856

Figure B 5 Future SUDS Dodder Main Channel and Dodder Urban 1 - 2 and 5 Year Return Period



5.890 0.000 5.890 7.830 0.000 7.830

5.890 18.656 24.546 7.830 22.876 30.706

5.890 37.311 43.201 7.830 45.751 53.581

5.890 55.967 61.857 7.830 68.627 76.457

5.777 74.622 80.400 7.680 91.502 99.183

4.600 93.278 97.878 6.115 114.378 120.493

3.136 106.337 109.473 4.169 130.391 134.560

2.439 111.933 114.373 3.243 137.254 140.496

0.000 124.571 124.571 0.000 152.750 152.750

Max 124.571 Max 152.750






9.640 0.000 9.640 11.820 0.000 11.820

9.640 26.611 36.251 11.820 30.937 42.757

9.640 53.221 62.861 11.820 61.875 73.695

9.640 79.832 89.472 11.820 92.812 104.632

9.456 106.442 115.898 11.594 123.749 135.343

7.528 133.053 140.581 9.231 154.686 163.917

5.133 151.680 156.813 6.294 176.342 182.636

3.992 159.663 163.656 4.895 185.624 190.519

0.000 177.690 177.690 0.000 206.581 206.581

Max 177.690 Max 206.581




14.470 0.000 14.470 23.050 0.000 23.050

14.470 35.980 50.450 23.050 51.306 74.356

14.470 71.960 86.430 23.050 102.613 125.663

14.470 107.941 122.411 23.050 153.919 176.969

14.193 143.921 158.114 22.609 205.225 227.834

11.300 179.901 191.201 18.001 256.532 274.533

7.705 205.087 212.792 12.273 292.446 304.720

5.993 215.881 221.874 9.546 307.838 317.384

0.000 240.255 240.255 0.000 342.594 342.594

Max 240.255 Max 342.594




B.3. Dodder Main Channel and Owendoher / Whitechurch


36.180 0.000 36.180 47.260 0.000 47.260 36.180 26.052 62.232 47.260 32.752 80.012 36.180 52.104 88.284 47.260 65.503 112.763 35.881 54.710 90.591 46.869 68.779 115.648 35.037 65.130 100.167 45.767 81.879 127.646 32.293 77.226 109.519 42.182 97.085 139.268 31.695 78.156 109.851 41.401 98.255 139.656 28.705 81.413 110.118 37.496 102.349 139.845 25.117 84.669 109.786 32.809 106.443 139.252 21.529 86.530 108.059 28.122 108.782 136.904 17.940 86.691 104.631 23.435 108.984 132.419 14.352 87.112 101.464 18.748 109.514 128.261 10.764 87.519 98.283 14.061 110.025 124.086 7.176 87.519 94.695 9.374 110.025 119.399 3.588 87.519 91.107 4.687 110.025 114.712 0.000 87.926 87.926 0.000 110.537 110.537 Max 110.118 Max 139.845

Figure B 9 Future SUDS Dodder Main Channel and Owendoher / Whitechurch 2 and 5 Year Return Period


56.620 0.000 56.620 70.510 0.000 70.510 56.620 38.657 95.277 70.510 47.579 118.089 56.620 77.313 133.933 70.510 95.157 165.667 56.152 81.179 137.331 69.927 99.915 169.842 54.831 96.641 151.472 68.282 118.947 187.229 50.537 114.589 165.126 62.935 141.037 203.971 49.601 115.970 165.571 61.769 142.736 204.505 44.922 120.802 165.724 55.942 148.683 204.625 39.306 125.634 164.940 48.949 154.631 203.580 33.691 128.395 162.086 41.956 158.029 199.986 28.076 128.633 156.709 34.964 158.322 193.286 22.461 129.258 151.719 27.971 159.091 187.062 16.846 129.862 146.708 20.978 159.835 180.813 11.230 129.862 141.092 13.985 159.835 173.820 5.615 129.862 135.477 6.993 159.835 166.827 0.000 130.466 130.466 0.000 160.578 160.578 Max 165.724 Max 204.625





82.630 0.000 82.630 96.460 0.000 96.460 82.630 55.502 138.132 96.460 64.711 161.171 82.630 111.004 193.634 96.460 129.422 225.882 81.947 116.555 198.502 95.663 135.893 231.556 80.019 138.756 218.774 93.412 161.777 255.189 73.752 164.524 238.277 86.097 191.821 277.918 72.387 166.507 238.893 84.502 194.132 278.635 65.558 173.444 239.002 76.530 202.221 278.752 57.363 180.382 237.745 66.964 210.310 277.274 49.168 184.347 233.515 57.398 214.932 272.330 40.974 184.688 225.662 47.831 215.331 263.162 32.779 185.586 218.364 38.265 216.377 254.642 24.584 186.453 211.037 28.699 217.388 246.087 16.389 186.453 202.842 19.133 217.388 236.520 8.195 186.453 194.647 9.566 217.388 226.954 0.000 187.320 187.320 0.000 218.399 218.399 Max 239.002 Max 278.752



112.330 0.000 112.330 158.970 0.000 158.970 112.330 75.476 187.806 158.970 108.340 267.310 112.330 150.953 263.283 158.970 216.681 375.651 111.402 158.501 269.902 157.656 227.515 385.171 108.780 188.691 297.472 153.947 270.851 424.798 100.261 223.734 323.995 141.891 321.152 463.043 98.405 226.429 324.834 139.263 325.021 464.284 89.121 235.864 324.985 126.125 338.564 464.689 77.981 245.298 323.280 110.359 352.106 462.466 66.841 250.690 317.531 94.594 359.845 454.439 55.701 251.154 306.855 78.828 360.512 439.340 44.561 252.374 296.935 63.062 362.263 425.326 33.420 253.554 286.974 47.297 363.956 411.253 22.280 253.554 275.834 31.531 363.956 395.487 11.140 253.554 264.694 15.766 363.956 379.722 0.000 254.733 254.733 0.000 365.649 365.649 Max 324.985 Max 464.689




B.4. Dodder Main Channel and Little Dargle


15.031 0.000 15.031 18.905 0.000 18.905 15.031 24.224 39.255 18.905 30.912 49.817 15.031 48.447 63.478 18.905 61.823 80.728 14.595 72.671 87.266 18.356 92.735 111.091 13.421 96.895 110.315 16.879 123.647 140.526 13.421 96.895 110.315 16.879 123.647 140.526 10.736 112.569 123.305 13.504 143.648 157.152 9.394 121.118 130.513 11.816 154.558 166.374 8.052 128.039 136.092 10.128 163.390 173.518 5.368 129.927 135.295 6.752 165.799 172.551 2.684 131.650 134.334 3.376 167.998 171.374 0.000 133.230 133.230 0.000 170.014 170.014 Max 136.092 Max 173.518

Figure B 13 Future SUDS Dodder Main Channel and Little Dargle 2 and 5 Year Return Period


22.201 0.000 22.201 26.688 0.000 26.688 22.201 36.839 59.040 26.688 45.821 72.509 22.201 73.679 95.880 26.688 91.643 118.331 21.557 110.518 132.075 25.914 137.464 163.377 19.822 147.358 167.180 23.829 183.285 207.114 19.822 147.358 167.180 23.829 183.285 207.114 15.858 171.195 187.053 19.063 212.934 231.997 13.876 184.197 198.073 16.680 229.106 245.786 11.893 194.723 206.616 14.297 242.198 256.495 7.929 197.593 205.522 9.531 245.769 255.300 3.964 200.214 204.179 4.766 249.029 253.794 0.000 202.617 202.617 0.000 252.017 252.017 Max 206.616 Max 256.495





30.296 0.000 30.296 34.142 0.000 34.142 30.296 53.819 84.115 34.142 63.128 97.270 30.296 107.638 137.934 34.142 126.255 160.397 29.417 161.457 190.874 33.151 189.383 222.534 27.050 215.276 242.326 30.484 252.511 282.994 27.050 215.276 242.326 30.484 252.511 282.994 21.640 250.100 271.740 24.387 293.358 317.745 18.935 269.095 288.030 21.339 315.638 336.977 16.230 284.472 300.702 18.290 333.675 351.965 10.820 288.666 299.486 12.194 338.594 350.787 5.410 292.495 297.905 6.097 343.085 349.182 0.000 296.005 296.005 0.000 347.202 347.202 Max 300.702 Max 351.965



38.262 0.000 38.262 49.056 0.000 49.056 38.262 74.026 112.288 49.056 107.330 156.386 38.262 148.052 186.314 49.056 214.661 263.717 37.152 222.077 259.229 47.632 321.991 369.624 34.162 296.103 330.266 43.800 429.321 473.121 34.162 296.103 330.266 43.800 429.321 473.121 27.330 344.002 371.332 35.040 498.771 533.811 23.914 370.129 394.043 30.660 536.652 567.312 20.497 391.279 411.777 26.280 567.318 593.598 13.665 397.048 410.713 17.520 575.681 593.201 6.832 402.314 409.147 8.760 583.317 592.077 0.000 407.142 407.142 0.000 590.317 590.317 Max 411.777 Max 593.598







9.124 0.000 9.124 12.217 0.000 12.217

9.124 16.048 25.172 12.217 20.405 32.622

9.124 32.096 41.220 12.217 40.810 53.027

9.124 48.145 57.269 12.217 61.214 73.431

9.124 64.193 73.317 12.217 81.619 93.836

8.795 80.241 89.036 11.776 102.024 113.800

7.778 96.289 104.067 10.414 122.429 132.843

6.533 109.128 115.661 8.748 138.753 147.501

6.149 112.337 118.486 8.233 142.833 151.067

3.267 121.966 125.233 4.374 155.076 159.450

0.000 124.106 124.106 0.000 157.797 157.797

Max 125.233 Max 159.450




15.531 0.000 15.531 20.929 0.000 20.929 15.531 24.192 39.723 20.929 29.882 50.811 15.531 48.384 63.915 20.929 59.764 80.693 15.531 72.576 88.107 20.929 89.646 110.575 15.531 96.769 112.300 20.929 119.528 140.457 14.971 120.961 135.931 20.174 149.410 169.584 13.239 145.153 158.392 17.841 179.292 197.133 11.121 164.507 175.628 14.986 203.198 218.184 10.467 169.345 179.812 14.105 209.174 223.279 5.560 183.860 189.421 7.493 227.104 234.597 0.000 187.086 187.086 0.000 231.088 231.088 Max 189.421 Max 234.597






26.055 0.000 26.055 32.343 0.000 32.343 26.055 34.907 60.962 32.343 40.715 73.058 26.055 69.815 95.870 32.343 81.429 113.772 26.055 104.722 130.777 32.343 122.144 154.487 26.055 139.629 165.684 32.343 162.858 195.201 25.115 174.537 199.651 31.176 203.573 234.748 22.210 209.444 231.654 27.570 244.287 271.858 18.657 237.370 256.026 23.159 276.859 300.018 17.559 244.351 261.911 21.797 285.002 306.799 9.328 265.296 274.624 11.580 309.430 321.010 0.000 269.950 269.950 0.000 314.859 314.859 Max 274.624 Max 321.010




40.079 0.000 40.079 65.698 0.000 65.698 40.079 47.465 87.544 65.698 67.839 133.537 40.079 94.930 135.009 65.698 135.677 201.375 40.079 142.395 182.474 65.698 203.516 269.214 40.079 189.860 229.939 65.698 271.355 337.053 38.633 237.325 275.958 63.327 339.193 402.520 34.165 284.790 318.955 56.004 407.032 463.036 28.699 322.762 351.461 47.043 461.303 508.346 27.010 332.255 359.266 44.276 474.871 519.146 14.349 360.734 375.084 23.522 515.574 539.095 0.000 367.063 367.063 0.000 524.619 524.619 Max 375.084 Max 539.095




B.6. Dodder Main Channel and Dundrum / Slang


12.408 0.000 12.408 17.232 0.000 17.232 12.408 18.533 30.941 17.232 23.615 40.847 12.408 37.065 49.473 17.232 47.230 64.462 12.408 55.598 68.006 17.232 70.845 88.077 12.408 74.131 86.539 17.232 94.460 111.692 12.408 92.663 105.071 17.232 118.074 135.306 11.207 111.196 122.403 15.564 141.689 157.254 9.606 129.728 139.335 13.341 165.304 178.645 9.606 129.728 139.335 13.341 165.304 178.645 6.404 145.335 151.739 8.894 185.190 194.084 3.202 147.455 150.657 4.447 187.892 192.339 0.000 148.261 148.261 0.000 188.919 188.919 Max 151.739 Max 194.084

Figure B 21 Future SUDS Dodder Main Channel and Dundrum / Slang - 2 and 5 Year Return Period


21.593 0.000 21.593 28.849 0.000 28.849 21.593 28.102 49.695 28.849 34.838 63.687 21.593 56.205 77.798 28.849 69.676 98.525 21.593 84.307 105.900 28.849 104.514 133.363 21.593 112.409 134.002 28.849 139.353 168.202 21.593 140.511 162.104 28.849 174.191 203.040 19.503 168.614 188.117 26.057 209.029 235.086 16.717 196.716 213.433 22.335 243.867 266.202 16.717 196.716 213.433 22.335 243.867 266.202 11.145 220.381 231.526 14.890 273.204 288.094 5.572 223.596 229.169 7.445 277.190 284.635 0.000 224.818 224.818 0.000 278.705 278.705 Max 231.526 Max 288.094





35.842 0.000 35.842 44.514 0.000 44.514 35.842 40.788 76.630 44.514 47.668 92.182 35.842 81.575 117.417 44.514 95.336 139.850 35.842 122.363 158.205 44.514 143.004 187.518 35.842 163.151 198.993 44.514 190.672 235.186 35.842 203.938 239.780 44.514 238.340 282.854 32.373 244.726 277.099 40.206 286.008 326.214 27.749 285.513 313.262 34.462 333.676 368.138 27.749 285.513 313.262 34.462 333.676 368.138 18.499 319.861 338.360 22.975 373.817 396.792 9.250 324.528 333.777 11.487 379.271 390.759 0.000 326.301 326.301 0.000 381.344 381.344 Max 338.360 Max 396.792



55.296 0.000 55.296 91.674 0.000 91.674 55.296 55.676 110.972 91.674 79.922 171.596 55.296 111.351 166.647 91.674 159.843 251.517 55.296 167.027 222.323 91.674 239.765 331.439 55.296 222.702 277.998 91.674 319.687 411.361 55.296 278.378 333.674 91.674 399.608 491.282 49.945 334.053 383.998 82.802 479.530 562.332 42.810 389.729 432.538 70.973 559.451 630.425 42.810 389.729 432.538 70.973 559.451 630.425 28.540 436.613 465.153 47.316 626.754 674.069 14.270 442.983 457.253 23.658 635.898 659.556 0.000 445.404 445.404 0.000 639.373 639.373 Max 465.153 Max 674.069




B.7. Dodder Main Channel and Dodder Urban 3+4



7.534 0.000 7.534 10.221 0.000 10.221 7.534 17.546 25.080 10.221 22.357 32.578 7.534 35.091 42.625 10.221 44.715 54.936 7.534 52.637 60.171 10.221 67.072 77.293 7.534 70.183 77.717 10.221 89.429 99.650 7.534 87.728 95.262 10.221 111.786 122.007 6.802 105.274 112.076 9.228 134.144 143.371 6.235 111.123 117.358 8.459 141.596 150.055 5.196 122.820 128.016 7.049 156.501 163.550 3.702 140.365 144.067 5.022 178.858 183.881 3.118 143.290 146.407 4.229 182.584 186.814 0.000 148.261 148.261 0.000 188.919 188.919 Max 148.261 Max 188.919

Figure B 25 Future SUDS Dodder Main Channel and Dodder Urban 3+4 - 2 and 5 Year Return Period



12.871 0.000 12.871 17.454 0.000 17.454 12.871 26.606 39.477 17.454 32.983 50.437 12.871 53.211 66.082 17.454 65.966 83.420 12.871 79.817 92.688 17.454 98.949 116.403 12.871 106.423 119.294 17.454 131.931 149.385 12.871 133.028 145.899 17.454 164.914 182.368 11.620 159.634 171.254 15.758 197.897 213.655 10.652 168.503 179.155 14.445 208.891 223.336 8.877 186.240 195.116 12.037 230.880 242.917 6.325 212.845 219.170 8.577 263.863 272.439 5.326 217.280 222.606 7.222 269.360 276.582 0.000 224.818 224.818 0.000 278.705 278.705 Max 224.818 Max 278.705






22.006 0.000 22.006 27.788 0.000 27.788 22.006 38.616 60.622 27.788 45.129 72.917 22.006 77.231 99.237 27.788 90.259 118.047 22.006 115.847 137.853 27.788 135.388 163.176 22.006 154.462 176.468 27.788 180.518 208.306 22.006 193.078 215.084 27.788 225.647 253.435 19.867 231.693 251.561 25.088 270.777 295.864 18.212 244.565 262.777 22.997 285.820 308.817 15.177 270.309 285.485 19.164 315.906 335.070 10.813 308.924 319.737 13.654 361.036 374.690 9.106 315.360 324.466 11.498 368.557 380.056 0.000 326.301 326.301 0.000 381.344 381.344 Max 326.301 Max 381.344




35.145 0.000 35.145 60.952 0.000 60.952 35.145 52.711 87.856 60.952 75.665 136.617 35.145 105.421 140.566 60.952 151.331 212.283 35.145 158.132 193.277 60.952 226.996 287.948 35.145 210.842 245.987 60.952 302.662 363.614 35.145 263.553 298.698 60.952 378.327 439.279 31.730 316.263 347.993 55.029 453.993 509.021 29.086 333.833 362.919 50.443 479.214 529.658 24.238 368.974 393.212 42.036 529.658 571.694 17.270 421.684 438.954 29.951 605.324 635.274 14.543 430.469 445.012 25.222 617.934 643.156 0.000 445.404 445.404 0.000 639.373 639.373 Max 445.404 Max 643.156




B.8. Owendoher and Whitechurch


0.000 13.672 13.672 0.000 16.432 16.432 3.035 13.672 16.707 4.058 16.432 20.490 6.071 13.672 19.743 8.117 16.432 24.549 9.106 13.672 22.778 12.175 16.432 28.607 12.142 13.447 25.589 16.233 16.162 32.395 15.177 12.093 27.270 20.292 14.534 34.825 16.695 11.086 27.781 22.321 13.324 35.645 18.213 7.391 25.603 24.350 8.883 33.233 18.213 7.391 25.603 24.350 8.883 33.233 18.355 3.695 22.050 24.540 4.441 28.982 18.743 0.000 18.743 25.059 0.000 25.059

Max 27.781 Max 35.645

Figure B 29 Future SUDS Owendoher and Whitechurch - 2 and 5 Year Return Period


0.000 19.433 19.433 0.000 23.862 23.862 4.825 19.433 24.258 5.955 23.862 29.817 9.650 19.433 29.083 11.910 23.862 35.772 14.476 19.433 33.909 17.865 23.862 41.727 19.301 19.113 38.414 23.820 23.470 47.289 24.126 17.188 41.314 29.775 21.105 50.880 26.539 15.757 42.296 32.752 19.349 52.101 28.951 10.505 39.456 35.730 12.899 48.629 28.951 10.505 39.456 35.730 12.899 48.629 29.177 5.252 34.430 36.009 6.450 42.458 29.794 0.000 29.794 36.770 0.000 36.770

Max 42.296 Max 52.101





0.000 27.710 27.710 0.000 32.091 32.091 6.936 27.710 34.646 8.052 32.091 40.143 13.871 27.710 41.581 16.104 32.091 48.195 20.807 27.710 48.517 24.157 32.091 56.248 27.743 27.254 54.997 32.209 31.563 63.772 34.679 24.509 59.188 40.261 28.384 68.645 38.147 22.469 60.615 44.287 26.021 70.308 41.614 14.979 56.594 48.313 17.347 65.661 41.614 14.979 56.594 48.313 17.347 65.661 41.940 7.490 49.429 48.691 8.674 57.365 42.826 0.000 42.826 49.720 0.000 49.720

Max 60.615 Max 70.308



0.000 37.100 37.100 0.000 51.741 51.741 9.329 37.100 46.429 13.063 51.741 64.804 18.658 37.100 55.758 26.126 51.741 77.867 27.987 37.100 65.087 39.189 51.741 90.930 37.316 36.490 73.805 52.251 50.890 103.142 46.644 32.814 79.459 65.314 45.764 111.078 51.309 30.083 81.392 71.846 41.954 113.800 55.973 20.055 76.029 78.377 27.970 106.347 55.973 20.055 76.029 78.377 27.970 106.347 56.411 10.028 66.438 78.989 13.985 92.974 57.603 0.000 57.603 80.659 0.000 80.659

Max 81.392 Max 113.800




Future No SUDS Scenario Dependence Analysis Results

The Rainfall-Runoff Catchment locations for the Future No SUDS Scenario are shown in Figure B-1.

Figure B-1 Rainfall-Runoff Catchment Locations (Future No SUDS Scenario)



B.9. Dodder Main Channel and Tallaght Stream



0.000 64.940 64.940 0.000 80.613 80.613

3.302 64.940 68.242 4.328 80.613 84.941

5.504 64.176 69.680 7.214 79.665 86.879

6.605 63.870 70.475 8.657 79.285 87.942

9.907 60.842 70.749 12.985 75.526 88.512

11.917 55.008 66.925 15.620 68.284 83.904

12.909 45.840 58.749 16.920 56.903 73.824

13.209 42.402 55.611 17.314 52.636 69.949

13.960 36.672 50.632 18.298 45.523 63.820

14.723 27.504 42.227 19.298 34.142 53.440

15.136 18.336 33.472 19.839 22.761 42.600

15.136 9.168 24.304 19.839 11.381 31.219

Max 70.749 Max 88.512

Figure B 33 Future No SUDS Dodder Main Channel and Tallaght Stream - 2 and 5 Year Return Period



0.000 93.902 93.902 0.000 113.680 113.680

5.313 93.902 99.215 6.869 113.680 120.549

8.855 92.797 101.653 11.449 112.343 123.791

10.626 92.355 102.982 13.738 111.808 125.546

15.939 87.977 103.916 20.608 106.507 127.114

19.174 79.541 98.714 24.789 96.294 121.082

20.770 66.284 87.053 26.852 80.245 107.097

21.253 61.312 82.565 27.477 74.226 101.703

22.460 53.027 75.487 29.038 64.196 93.234

23.688 39.770 63.458 30.625 48.147 78.772

24.352 26.514 50.865 31.484 32.098 63.582

24.352 13.257 37.609 31.484 16.049 47.533

Max 103.916 Max 127.114




50 Year Joint Probability 100 Year Joint Probability Tallaght Dodder Main Sum Tallaght Dodder Main Sum

0.000 130.928 130.928 0.000 150.607 150.607 8.309 130.928 139.237 10.041 150.607 160.648

13.849 129.388 143.236 16.735 148.835 165.570 16.619 128.772 145.390 20.081 148.126 168.208 24.928 122.666 147.594 30.122 141.103 171.226 29.986 110.904 140.889 36.234 127.573 163.807 32.482 92.420 124.901 39.250 106.311 145.561 33.237 85.488 118.725 40.163 98.338 138.500 35.126 73.936 109.061 42.445 85.049 127.494 37.045 55.452 92.497 44.765 63.786 108.551 38.084 36.968 75.052 46.020 42.524 88.544 38.084 18.484 56.568 46.020 21.262 67.282 Max 147.594 Max 171.226


200 Year Joint Probability 1000 Year Joint Probability Tallaght Dodder Main Sum Tallaght Dodder Main Sum

0.000 173.147 173.147 0.000 239.248 239.248 12.132 173.147 185.279 18.859 239.248 258.107 20.220 171.110 191.330 31.432 236.433 267.866 24.264 170.295 194.559 37.719 235.307 273.026 36.396 162.221 198.617 56.578 224.151 280.730 43.780 146.666 190.446 68.058 202.657 270.715 47.425 122.221 169.646 73.723 168.881 242.604 48.528 113.055 161.582 75.438 156.215 231.653 51.285 97.777 149.062 79.724 135.105 214.829 54.088 73.333 127.421 84.082 101.329 185.410 55.605 48.889 104.493 86.439 67.552 153.992 55.605 24.444 80.049 86.439 33.776 120.215 Max 198.617 Max 280.730






Urban 1 Dodder Main Sum Urban 1 Dodder Main Sum

0.000 80.263 80.263 0.000 100.697 100.697

1.971 74.324 76.295 2.580 93.246 95.826

2.759 70.545 73.304 3.612 88.505 92.117

3.942 62.300 66.241 5.160 78.160 83.320

4.161 60.467 64.628 5.447 75.861 81.308

5.321 50.389 55.711 6.966 63.218 70.184

5.913 40.311 46.224 7.740 50.574 58.314

5.913 40.311 46.224 7.740 50.574 58.314

6.405 30.234 36.639 8.385 37.931 46.316

6.529 20.156 26.684 8.546 25.287 33.834

6.775 10.078 16.853 8.869 12.644 21.513

6.775 0.000 6.775 8.869 0.000 8.869

Max 80.263 Max 100.697

Figure B 37 Future No SUDS Dodder Main Channel and Dodder Urban 1 - 2 and 5 Year Return Period



0.000 118.555 118.555 0.000 145.553 145.553

3.206 109.783 112.989 4.190 134.783 138.974

4.489 104.201 108.690 5.866 127.930 133.796

6.413 92.021 98.434 8.381 112.977 121.358

6.769 89.315 96.084 8.846 109.654 118.500

8.657 74.429 83.086 11.314 91.379 102.692

9.619 59.543 69.163 12.571 73.103 85.674

9.619 59.543 69.163 12.571 73.103 85.674

10.421 44.657 55.078 13.618 54.827 68.445

10.621 29.772 40.393 13.880 36.551 50.432

11.022 14.886 25.908 14.404 18.276 32.680

11.022 0.000 11.022 14.404 0.000 14.404

Max 118.555 Max 145.553






0.000 169.483 169.483 0.000 197.196 197.196

5.095 156.943 162.038 6.175 182.605 188.781

7.133 148.963 156.096 8.646 173.320 181.966

10.190 131.551 141.741 12.351 153.062 165.413

10.756 127.682 138.438 13.037 148.560 161.597

13.756 106.402 120.158 16.674 123.800 140.474

15.285 85.122 100.406 18.526 99.040 117.566

15.285 85.122 100.406 18.526 99.040 117.566

16.559 63.841 80.400 20.070 74.280 94.350

16.877 42.561 59.438 20.456 49.520 69.976

17.514 21.280 38.794 21.228 24.760 45.988

17.514 0.000 17.514 21.228 0.000 21.228

Max 169.483 Max 197.196




0.000 229.439 229.439 0.000 326.756 326.756

7.470 212.463 219.932 11.567 302.579 314.146

10.458 201.659 212.117 16.193 287.194 303.387

14.939 178.089 193.028 23.133 253.626 276.759

15.769 172.851 188.620 24.418 246.166 270.584

20.168 144.042 164.211 31.230 205.138 236.368

22.409 115.234 137.643 34.700 164.111 198.810

22.409 115.234 137.643 34.700 164.111 198.810

24.276 86.425 110.702 37.591 123.083 160.674

24.743 57.617 82.360 38.314 82.055 120.370

25.677 28.808 54.485 39.760 41.028 80.788

25.677 0.000 25.677 39.760 0.000 39.760

Max 229.439 Max 326.756




B.11. Dodder Main Channel and Owendoher / Whitechurch


0.000 87.038 87.038 0.000 109.566 109.566 2.894 87.038 89.932 3.833 109.566 113.399 5.789 87.038 92.827 7.666 109.566 117.232 8.683 87.038 95.721 11.500 109.566 121.066

11.577 87.038 98.615 15.333 109.566 124.899 14.471 86.591 101.063 19.166 109.004 128.170 17.366 86.591 103.957 22.999 109.004 132.003 20.260 85.519 105.779 26.833 107.654 134.487 23.154 84.117 107.271 30.666 105.889 136.555 26.048 83.697 109.745 34.499 105.360 139.859 28.943 81.113 110.056 38.332 102.108 140.440 31.837 75.355 107.192 42.165 94.859 137.025 32.995 73.603 106.597 43.699 92.653 136.352 34.731 65.717 100.448 45.999 82.726 128.725 35.214 63.088 98.301 46.637 79.417 126.054 35.558 52.573 88.131 47.094 66.181 113.275 35.972 42.059 78.030 47.641 52.945 100.586 35.972 21.029 57.001 47.641 26.472 74.114 36.385 0.000 36.385 48.189 0.000 48.189

Max 110.056 Max 140.440

Figure B 41 Future No SUDS Dodder Main Channel and Owendoher / Whitechurch - 2 and 5 Year Return Period


0.000 129.577 129.577 0.000 159.957 159.957 4.630 129.577 134.207 5.828 159.957 165.785 9.260 129.577 138.837 11.656 159.957 171.613 13.889 129.577 143.466 17.485 159.957 177.442 18.519 129.577 148.096 23.313 159.957 183.270 23.149 128.912 152.061 29.141 159.136 188.277 27.779 128.912 156.691 34.969 159.136 194.105 32.408 127.316 159.724 40.798 157.166 197.963 37.038 125.229 162.267 46.626 154.589 201.215 41.668 124.603 166.271 52.454 153.816 206.270 46.298 120.756 167.054 58.282 149.068 207.350 50.928 112.184 163.112 64.110 138.486 202.597 52.780 109.575 162.355 66.442 135.266 201.707 55.557 97.835 153.392 69.939 120.773 190.711 56.329 93.922 150.251 70.910 115.942 186.852 56.880 78.268 135.148 71.604 96.618 168.222 57.542 62.614 120.156 72.436 77.295 149.731 57.542 31.307 88.849 72.436 38.647 111.084 58.203 0.000 58.203 73.269 0.000 73.269

Max 167.054 Max 207.350





0.000 186.997 186.997 0.000 218.424 218.424 6.884 186.997 193.881 8.097 218.424 226.521

13.767 186.997 200.764 16.195 218.424 234.619 20.651 186.997 207.648 24.292 218.424 242.716 27.534 186.997 214.531 32.390 218.424 250.814 34.418 186.037 220.455 40.487 217.303 257.790 41.301 186.037 227.339 48.584 217.303 265.887 48.185 183.734 231.919 56.682 214.613 271.294 55.068 180.722 235.790 64.779 211.094 275.874 61.952 179.818 241.770 72.877 210.039 282.916 68.835 174.268 243.103 80.974 203.555 284.529 75.719 161.897 237.616 89.071 189.105 278.177 78.472 158.132 236.604 92.310 184.708 277.018 82.603 141.189 223.792 97.169 164.917 262.086 83.750 135.541 219.291 98.518 158.321 256.839 84.569 112.951 197.520 99.482 131.934 231.416 85.553 90.361 175.914 100.639 105.547 206.186 85.553 45.180 130.733 100.639 52.774 153.413 86.536 0.000 86.536 101.796 0.000 101.796

Max 243.103 Max 284.529



0.000 255.116 255.116 0.000 366.516 366.516 9.499 255.116 264.615 13.660 366.516 380.176 18.997 255.116 274.113 27.320 366.516 393.836 28.496 255.116 283.612 40.979 366.516 407.495 37.994 255.116 293.110 54.639 366.516 421.155 47.493 253.807 301.300 68.299 364.635 432.934 56.992 253.807 310.798 81.959 364.635 446.594 66.490 250.664 317.155 95.618 360.120 455.739 75.989 246.555 322.544 109.278 354.217 463.495 85.487 245.322 330.810 122.938 352.446 475.384 94.986 237.750 332.736 136.598 341.566 478.164

104.485 220.872 325.357 150.258 317.319 467.577 108.284 215.736 324.020 155.722 309.940 465.661 113.983 192.621 306.604 163.917 276.732 440.649 115.566 184.916 300.483 166.194 265.663 431.857 116.697 154.097 270.794 167.820 221.386 389.206 118.054 123.278 241.332 169.772 177.108 346.880 118.054 61.639 179.693 169.772 88.554 258.326 119.411 0.000 119.411 171.723 0.000 171.723

Max 332.736 Max 478.164




B.12. Dodder Main Channel and Little Dargle


0.000 135.424 135.424 0.000 173.540 173.540 2.998 135.021 138.019 4.074 173.024 177.098 5.996 133.471 139.467 8.149 171.037 179.186 8.995 130.807 139.802 12.223 167.624 179.847 9.812 126.960 136.772 13.334 162.694 176.028

11.564 112.853 124.418 15.715 144.617 160.332 11.993 108.823 120.816 16.297 139.452 155.749 12.930 98.747 111.676 17.570 126.540 144.110 13.325 84.640 97.965 18.108 108.463 126.570 13.563 70.533 84.097 18.431 90.385 108.817 14.037 56.427 70.464 19.075 72.308 91.383 14.037 42.320 56.357 19.075 54.231 73.306 14.037 28.213 42.250 19.075 36.154 55.229 14.037 14.107 28.144 19.075 18.077 37.152 14.037 0.000 14.037 19.075 0.000 19.075

Max 139.802 Max 179.847

Figure B 45 Future No SUDS Dodder Main Channel and Little Dargle - 2 and 5 Year Return Period


0.000 207.539 207.539 0.000 259.328 259.328 4.809 206.921 211.731 5.836 258.556 264.392 9.619 204.546 214.165 11.671 255.588 267.259

14.428 200.464 214.892 17.507 250.487 267.994 15.740 194.568 210.308 19.098 243.120 262.218 18.551 172.949 191.500 22.509 216.107 238.615 19.238 166.772 186.010 23.342 208.389 231.731 20.741 151.331 172.071 25.166 189.093 214.259 21.375 129.712 151.087 25.936 162.080 188.016 21.757 108.093 129.850 26.399 135.067 161.466 22.517 86.475 108.992 27.321 108.053 135.374 22.517 64.856 87.373 27.321 81.040 108.361 22.517 43.237 65.754 27.321 54.027 81.348 22.517 21.619 44.136 27.321 27.013 54.334 22.517 0.000 22.517 27.321 0.000 27.321

Max 214.892 Max 267.994





0.000 305.550 305.550 0.000 359.381 359.381 6.687 304.641 311.328 7.624 358.311 365.936

13.375 301.143 314.518 15.249 354.198 369.446 20.062 295.134 315.196 22.873 347.129 370.003 21.886 286.453 308.339 24.953 336.920 361.872 25.794 254.625 280.419 29.408 299.484 328.893 26.749 245.531 272.281 30.498 288.788 319.286 28.839 222.797 251.636 32.880 262.049 294.929 29.722 190.969 220.690 33.886 224.613 258.499 30.252 159.141 189.393 34.491 187.178 221.669 31.309 127.313 158.622 35.696 149.742 185.438 31.309 95.484 126.793 35.696 112.307 148.003 31.309 63.656 94.965 35.696 74.871 110.567 31.309 31.828 63.137 35.696 37.436 73.132 31.309 0.000 31.309 35.696 0.000 35.696

Max 315.196 Max 370.003



0.000 422.344 422.344 0.000 613.976 613.976 8.662 421.087 429.749 11.548 612.149 623.696

17.324 416.253 433.577 23.095 605.121 628.216 25.986 407.946 433.932 34.643 593.045 627.688 28.348 395.948 424.296 37.792 575.603 613.395 33.411 351.953 385.364 44.541 511.647 556.188 34.648 339.384 374.032 46.191 493.374 539.564 37.355 307.959 345.314 49.799 447.691 497.490 38.498 263.965 302.463 51.323 383.735 435.058 39.185 219.971 259.156 52.239 319.779 372.019 40.554 175.977 216.531 54.064 255.823 309.887 40.554 131.983 172.537 54.064 191.868 245.932 40.554 87.988 128.542 54.064 127.912 181.976 40.554 43.994 84.548 54.064 63.956 118.020 40.554 0.000 40.554 54.064 0.000 54.064

Max 433.932 Max 628.216





2 Year Joint Probability 5 Year Joint Probability Urban 2 Dodder Main Sum Urban 2 Dodder Main Sum

0.000 123.423 123.423 0.000 157.755 157.755 4.929 114.152 119.081 6.483 145.906 152.389 5.633 110.693 116.326 7.409 141.484 148.894 7.570 96.857 104.426 9.956 123.799 133.755 9.242 83.020 92.262 12.156 106.113 118.269 9.858 75.333 85.191 12.966 96.288 109.254 10.754 69.183 79.937 14.145 88.428 102.573 11.202 55.347 66.549 14.734 70.742 85.477 11.572 41.510 53.082 15.221 53.057 68.278 12.001 27.673 39.674 15.785 35.371 51.156 12.001 13.837 25.838 15.785 17.686 33.471 12.001 0.000 12.001 15.785 0.000 15.785

Max 123.423 Max 157.755



0.000 187.780 187.780 0.000 233.226 233.226 8.115 173.675 181.791 10.720 215.708 226.428 9.275 168.413 177.687 12.252 209.171 221.423 12.463 147.361 159.824 16.464 183.025 199.488 15.216 126.309 141.526 20.101 156.878 176.979 16.231 114.614 130.845 21.441 142.353 163.794 17.706 105.258 122.964 23.390 130.732 154.122 18.444 84.206 102.650 24.365 104.586 128.950 19.053 63.155 82.208 25.170 78.439 103.609 19.759 42.103 61.862 26.102 52.293 78.395 19.759 21.052 40.811 26.102 26.146 52.248 19.759 0.000 19.759 26.102 0.000 26.102

Max 187.780 Max 233.226





0.000 273.533 273.533 0.000 320.220 320.220 13.150 252.987 266.137 16.084 296.168 312.252 15.028 245.321 260.349 18.382 287.193 305.575 20.194 214.656 234.850 24.700 251.294 275.994 24.656 183.991 208.647 30.157 215.395 245.552 26.300 166.955 193.254 32.168 195.451 227.619 28.691 153.326 182.016 35.092 179.496 214.588 29.886 122.661 152.547 36.555 143.596 180.151 30.874 91.995 122.869 37.762 107.697 145.460 32.017 61.330 93.347 39.161 71.798 110.959 32.017 30.665 62.682 39.161 35.899 75.060 32.017 0.000 32.017 39.161 0.000 39.161

Max 273.533 Max 320.220



0.000 374.527 374.527 0.000 538.239 538.239 19.639 346.395 366.035 31.106 497.811 528.917 22.445 335.899 358.343 35.550 482.726 518.276 30.160 293.911 324.071 47.770 422.385 470.155 36.823 251.924 288.747 58.324 362.044 420.368 39.278 228.598 267.876 62.213 328.522 390.734 42.849 209.937 252.786 67.868 301.703 369.572 44.634 167.949 212.584 70.696 241.363 312.059 46.109 125.962 172.071 73.032 181.022 254.054 47.817 83.975 131.792 75.737 120.681 196.418 47.817 41.987 89.804 75.737 60.341 136.078 47.817 0.000 47.817 75.737 0.000 75.737

Max 374.527 Max 538.239




B.14. Dodder Main Channel and Dundrum / Slang


0.000 149.461 149.461 0.000 192.615 192.615 4.714 146.877 151.591 6.769 189.285 196.054 6.599 142.797 149.396 9.477 184.027 193.504 9.091 128.517 137.608 13.055 165.624 178.679 9.427 126.732 136.160 13.538 163.324 176.862

11.077 114.238 125.315 15.908 147.222 163.129 12.046 99.958 112.004 17.299 128.819 146.118 12.616 85.678 98.294 18.118 110.416 128.534 13.309 71.399 84.708 19.113 92.014 111.127 13.309 57.119 70.428 19.113 73.611 92.724 13.309 42.839 56.148 19.113 55.208 74.321 13.309 28.559 41.868 19.113 36.805 55.918 13.309 14.280 27.589 19.113 18.403 37.516 13.309 0.000 13.309 19.113 0.000 19.113

Max 151.591 Max 196.054

Figure B 53 Future No SUDS Dodder Main Channel and Dundrum / Slang - 2 and 5 Year Return Period


0.000 230.056 230.056 0.000 286.649 286.649 8.591 226.079 234.670 11.582 281.693 293.276

12.027 219.799 231.826 16.215 273.868 290.084 16.568 197.819 214.387 22.337 246.482 268.819 17.182 195.071 212.253 23.165 243.058 266.223 20.189 175.839 196.028 27.218 219.095 246.313 21.955 153.859 175.814 29.599 191.708 221.307 22.994 131.879 154.873 31.000 164.321 195.321 24.257 109.899 134.156 32.703 136.934 169.637 24.257 87.919 112.176 32.703 109.547 142.250 24.257 65.940 90.197 32.703 82.161 114.864 24.257 43.960 68.217 32.703 54.774 87.477 24.257 21.980 46.237 32.703 27.387 60.090 24.257 0.000 24.257 32.703 0.000 32.703

Max 234.670 Max 293.276





0.000 336.859 336.859 0.000 395.077 395.077 14.434 331.035 345.469 17.938 388.247 406.185 20.207 321.840 342.047 25.113 377.462 402.576 27.836 289.656 317.492 34.595 339.716 374.311 28.867 285.633 314.500 35.876 334.998 370.874 33.919 257.472 291.391 42.155 301.970 344.124 36.886 225.288 262.174 45.842 264.223 310.066 38.631 193.104 231.735 48.011 226.477 274.488 40.754 160.920 201.674 50.649 188.731 239.380 40.754 128.736 169.490 50.649 150.985 201.634 40.754 96.552 137.306 50.649 113.239 163.888 40.754 64.368 105.122 50.649 75.492 126.141 40.754 32.184 72.938 50.649 37.746 88.395 40.754 0.000 40.754 50.649 0.000 50.649

Max 345.469 Max 406.185



0.000 462.898 462.898 0.000 668.040 668.040 22.257 454.895 477.152 36.599 656.491 693.089 31.160 442.259 473.419 51.238 638.255 689.493 42.924 398.033 440.957 70.583 574.429 645.012 44.514 392.505 437.019 73.197 566.451 639.648 52.304 353.807 406.111 86.007 510.604 596.610 56.879 309.581 366.460 93.530 446.778 540.308 59.570 265.356 324.925 97.955 382.953 480.908 62.843 221.130 283.973 103.337 319.127 422.464 62.843 176.904 239.747 103.337 255.302 358.639 62.843 132.678 195.521 103.337 191.476 294.813 62.843 88.452 151.295 103.337 127.651 230.988 62.843 44.226 107.069 103.337 63.825 167.162 62.843 0.000 62.843 103.337 0.000 103.337

Max 477.152 Max 693.089




B.15. Dodder Main Channel and Dodder Urban 3+4

2 Year Joint Probability 5 Year Joint Probability Urban 3+4 Dodder Main Sum Urban 3+4 Dodder Main Sum

0.000 162.770 162.770 0.000 211.728 211.728 0.000 162.770 162.770 0.000 211.728 211.728 1.828 161.425 163.253 2.427 209.978 212.405 3.657 152.905 156.562 4.855 198.896 203.751 4.440 147.973 152.413 5.895 192.480 198.375 5.485 141.396 146.881 7.282 183.925 191.207 6.247 133.175 139.422 8.293 173.232 181.525 7.313 120.228 127.541 9.709 156.390 166.099 7.435 118.378 125.813 9.871 153.984 163.855 8.564 103.581 112.145 11.370 134.736 146.106 8.853 88.784 97.637 11.753 115.488 127.241 8.853 73.986 82.839 11.753 96.240 107.993 8.853 59.189 68.042 11.753 76.992 88.745 8.853 44.392 53.245 11.753 57.744 69.497 8.853 29.595 38.448 11.753 38.496 50.249 8.853 14.797 23.650 11.753 19.248 31.001 8.853 0.000 8.853 11.753 0.000 11.753

Max 163.253 Max 212.405

Figure B 57 Future No SUDS Dodder Main Channel and Dodder Urban 3+4 - 2 and 5 Year Return Period


0.000 254.313 254.313 0.000 319.352 319.352 0.000 254.313 254.313 0.000 319.352 319.352 3.016 252.211 255.228 4.024 316.713 320.737 6.033 238.900 244.933 8.049 299.997 308.046 7.326 231.194 238.519 9.774 290.320 300.094 9.049 220.918 229.968 12.073 277.417 289.490

10.306 208.074 218.380 13.750 261.288 275.038 12.066 187.845 199.911 16.098 235.885 251.983 12.267 184.955 197.222 16.366 232.256 248.622 14.130 161.836 175.965 18.852 203.224 222.076 14.606 138.716 153.322 19.487 174.192 193.679 14.606 115.597 130.203 19.487 145.160 164.647 14.606 92.477 107.083 19.487 116.128 135.615 14.606 69.358 83.964 19.487 87.096 106.583 14.606 46.239 60.845 19.487 58.064 77.551 14.606 23.119 37.725 19.487 29.032 48.519 14.606 0.000 14.606 19.487 0.000 19.487

Max 255.228 Max 320.737





0.000 377.613 377.613 0.000 445.726 445.726 0.000 377.613 377.613 0.000 445.726 445.726 5.014 374.492 379.507 6.259 442.042 448.301

10.029 354.727 364.756 12.517 418.712 431.230 12.178 343.285 355.462 15.200 405.205 420.405 15.043 328.027 343.070 18.776 387.196 405.972 17.132 308.956 326.088 21.384 364.685 386.069 20.057 278.919 298.976 25.035 329.229 354.264 20.392 274.628 295.019 25.452 324.164 349.616 23.488 240.299 263.787 29.317 283.644 312.961 24.280 205.971 230.251 30.305 243.123 273.428 24.280 171.642 195.922 30.305 202.603 232.908 24.280 137.314 161.594 30.305 162.082 192.387 24.280 102.985 127.265 30.305 121.562 151.867 24.280 68.657 92.937 30.305 81.041 111.346 24.280 34.328 58.608 30.305 40.521 70.826 24.280 0.000 24.280 30.305 0.000 30.305

Max 379.507 Max 448.301



0.000 525.741 525.741 0.000 771.377 771.377 0.000 525.741 525.741 0.000 771.377 771.377 7.825 521.396 529.221 13.219 765.002 778.221

15.651 493.878 509.529 26.438 724.627 751.065 19.004 477.946 496.951 32.103 701.252 733.355 23.476 456.704 480.180 39.657 670.085 709.742 26.736 430.152 456.888 45.164 631.127 676.291 31.301 388.331 419.633 52.875 569.767 622.642 31.823 382.357 414.180 53.757 561.001 614.758 36.655 334.562 371.218 61.920 490.876 552.796 37.891 286.768 324.659 64.007 420.751 484.758 37.891 238.973 276.864 64.007 350.626 414.633 37.891 191.179 229.070 64.007 280.501 344.508 37.891 143.384 181.275 64.007 210.376 274.383 37.891 95.589 133.480 64.007 140.250 204.257 37.891 47.795 85.686 64.007 70.125 134.132 37.891 0.000 37.891 64.007 0.000 64.007

Max 529.221 Max 778.221




B.16. Owendoher and Whitechurch


Owendoher Whitechurch Sum Owendoher Whitechurch Sum

16.650 0.000 16.650 21.678 0.000 21.678

16.650 2.954 19.604 21.678 3.573 25.251

16.294 5.909 22.203 21.215 7.146 28.360

15.157 8.568 23.725 19.734 10.362 30.096

14.877 8.863 23.740 19.369 10.719 30.088

12.631 9.891 22.522 16.445 11.962 28.407

10.105 10.340 20.445 13.156 12.505 25.662

7.579 10.388 17.967 9.867 12.563 22.430

5.052 10.388 15.440 6.578 12.563 19.141

2.526 10.388 12.914 3.289 12.563 15.852

0.000 10.388 10.388 0.000 12.563 12.563

Max 23.740 Max 30.096

Figure B 61 Future No SUDS Owendoher and Whitechurch - 2 and 5 Year Return Period


25.486 0.000 25.486 31.099 0.000 31.099

25.486 4.282 29.768 31.099 5.373 36.472

24.941 8.564 33.505 30.434 10.745 41.179

23.201 12.418 35.619 28.311 15.581 43.892

22.771 12.846 35.617 27.787 16.118 43.905

19.334 14.335 33.670 23.592 17.987 41.579

15.467 14.987 30.454 18.874 18.804 37.678

11.601 15.056 26.657 14.155 18.891 33.046

7.734 15.056 22.790 9.437 18.891 28.328

3.867 15.056 18.923 4.718 18.891 23.609

0.000 15.056 15.056 0.000 18.891 18.891

Max 35.619 Max 43.905





35.961 0.000 35.961 41.482 0.000 41.482

35.961 6.353 42.314 41.482 7.499 48.981

35.192 12.705 47.898 40.595 14.998 55.593

32.737 18.423 51.160 37.763 21.748 59.510

32.131 19.058 51.189 37.064 22.497 59.561

27.281 21.268 48.549 31.469 25.106 56.575

21.825 22.235 44.059 25.175 26.247 51.422

16.368 22.337 38.705 18.881 26.368 45.249

10.912 22.337 33.249 12.588 26.368 38.956

5.456 22.337 27.793 6.294 26.368 32.662

0.000 22.337 22.337 0.000 26.368 26.368

Max 51.189 Max 59.561



47.777 0.000 47.777 66.093 0.000 66.093 47.777 8.844 56.621 66.093 12.949 79.042 46.756 17.688 64.444 64.680 25.898 90.578 43.494 25.648 69.141 60.167 37.553 97.720 42.688 26.532 69.220 59.053 38.848 97.901 36.245 29.609 65.853 50.140 43.352 93.491 28.996 30.954 59.950 40.112 45.322 85.434 21.747 31.097 52.844 30.084 45.531 75.615 14.498 31.097 45.595 20.056 45.531 65.587 7.249 31.097 38.346 10.028 45.531 55.559 0.000 31.097 31.097 0.000 45.531 45.531

Max 69.220 Max 97.901


APPENDIX C

Future Scenario Hydrographs

MDW0259Rp0021 C1 Rev F01

Future SUDS Scenario Hydrographs

Tributary Hydrographs

C.1. Tallaght NAM

Figure C 1 Tallaght NAM Future SUDS Design Event Hydrographs


C.2. Owendoher NAM

Figure C 2 Owendoher NAM Future SUDS Design Event Hydrographs

C.3. Whitechurch NAM

Figure C 3 Whitechurch NAM Future SUDS Design Event Hydrographs


C.4. Little Dargle NAM

Figure C 4 Little Dargle NAM Future SUDS Design Event Hydrographs

C.5. Dundrum NAM

Figure C 5 Dundrum NAM Future SUDS Design Event Hydrographs


C.6. Tallaght Urban

Figure C 6 Tallaght Urban Future SUDS Design Event Hydrographs

C.7. Owendoher Whitechurch Urban

Figure C 7 Owendoher Whitechurch Urban Future SUDS Design Event Hydrographs


C.8. Little Dargle Urban

Figure C 8 Little Dargle Urban Future SUDS Design Event Hydrographs

C.9. Dundrum Urban 1 + 2

Figure C 9 Dundrum Urban 1 + 2 Future SUDS Design Event Hydrographs


Dodder Main Channel Hydrographs

C.10. Bohernabreena NAM

Figure C 10 Bohernabreena NAM Future SUDS Design Event Hydrographs

C.11. Dodder Main Channel NAM

Figure C 11 Dodder Main Channel NAM Future SUDS Design Event Hydrographs


C.12. Dodder Urban 1

Figure C 12 Dodder Urban 1 Future SUDS Design Event Hydrographs


Figure C 13 Dodder Urban 2 Future SUDS Design Event Hydrographs


C.14. Dodder Urban 3 + 4

Figure C 14 Dodder Urban 3+4 Future SUDS Design Event Hydrographs


Future No SUDS Scenario Hydrographs

Tributary Hydrographs

C.15. Tallaght NAM

Figure C 15 Tallaght NAM Future No SUDS Design Event Hydrographs


C.16. Owendoher NAM

Figure C 16 Owendoher NAM Future No SUDS Design Event Hydrographs

C.17. Whitechurch NAM

Figure C 17 Whitechurch NAM Future No SUDS Design Event Hydrographs


C.18. Little Dargle NAM

Figure C 18 Little Dargle NAM Future No SUDS Design Event Hydrographs

C.19. Dundrum NAM

Figure C 19 Dundrum NAM Future No SUDS Design Event Hydrographs


C.20. Tallaght Urban

Figure C 20 Tallaght Urban Future No SUDS Design Event Hydrographs

C.21. Owendoher Whitechurch Urban

Figure C 21 Owendoher Whitechurch Urban Future No SUDS Design Event Hydrographs


C.22. Little Dargle Urban

Figure C 22 Little Dargle Urban Future No SUDS Design Event Hydrographs

C.23. Dundrum Urban 1 + 2

Figure C 23 Dundrum Urban 1 +2 Future No SUDS Design Event Hydrographs


Dodder Main Channel Hydrographs

C.24. Bohernabreena NAM

Figure C 24 Bohernabreena NAM Future No SUDS Design Event Hydrographs

C.25. Dodder Main Channel NAM

Figure C 25 Dodder Main Channel NAM Future No SUDS Design Event Hydrographs



Figure C 26 Dodder Urban 1 Future No SUDS Design Event Hydrographs


Figure C 27 Dodder Urban 2 Future No SUDS Design Event Hydrographs


C.28. Dodder Urban 3 + 4

Figure C 28 Dodder Urban 3 + 4 Future No SUDS Design Event Hydrographs

APPENDIX D

Peak Water Levels and Peak Water Profiles

MDW0259Rp0021 D1 Rev F01

Tallaght Stream

50% AEP 20%

AEP 10% AEP 4% AEP 2% AEP 1% AEP 0.5%

AEP 0.1% AEP

Chainage X Y Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q

(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Tallaght Stream Main Channel_Present Day

0.00 306552.5 226801.5 107.93 1.38 108.02 1.82 108.09 2.15 108.17 2.65 108.24 3.09 108.31 3.59 108.38 4.15 108.56 5.83 4.67 306557.2 226801.2 107.91 1.38 108.01 1.82 108.07 2.16 108.16 2.65 108.22 3.09 108.29 3.59 108.36 4.16 108.54 5.85 90.00 306642.3 226795.5 107.71 1.40 107.80 1.84 107.85 2.18 107.92 2.69 107.97 3.13 108.02 3.64 108.07 4.22 108.20 5.95 270.00 306821.7 226781.6 106.64 1.42 106.71 1.87 106.76 2.22 106.82 2.74 106.86 3.19 106.92 3.72 106.97 4.32 107.14 6.10 339.78 306890.9 226772.8 106.53 1.42 106.58 1.89 106.61 2.25 106.66 2.77 106.70 3.23 106.74 3.77 106.79 4.37 106.99 6.19 342.57 306893.7 226772.5 106.27 1.85 106.43 2.48 106.48 3.00 106.54 3.79 106.60 4.50 106.66 5.31 106.74 6.30 106.96 9.27 360.00 306911.0 226770.1 106.03 2.28 106.14 3.07 106.23 3.76 106.35 4.81 106.44 5.77 106.53 6.88 106.63 8.22 106.90 12.36 520.00 307066.0 226730.7 105.72 2.29 105.83 3.09 105.91 3.79 106.01 4.85 106.09 5.82 106.18 6.93 106.30 8.25 106.60 12.44 620.00 307158.2 226691.8 105.26 2.31 105.37 3.12 105.46 3.82 105.57 4.89 105.66 5.86 105.77 6.97 106.06 8.18 106.45 12.53 709.45 307242.5 226662.0 104.79 2.33 104.93 3.14 105.04 3.85 105.20 4.93 105.34 5.91 105.53 7.01 105.99 8.13 106.40 12.65 874.54 307373.1 226561.0 104.12 3.96 104.24 5.26 104.32 6.37 104.44 8.04 104.54 9.54 104.65 11.19 104.76 12.90 105.13 19.52 950.00 307438.2 226522.9 104.00 5.58 104.10 7.39 104.18 8.90 104.28 11.15 104.36 13.17 104.44 15.37 104.53 17.67 104.83 26.35 1050.00 307524.6 226472.5 103.78 5.60 103.88 7.40 103.96 8.92 104.07 11.18 104.16 13.20 104.25 15.41 104.35 17.73 104.71 26.36 1097.21 307567.8 226453.6 103.67 5.61 103.77 7.41 103.85 8.93 103.96 11.20 104.06 13.22 104.16 15.44 104.26 17.76 104.62 26.36 1099.69 307570.1 226452.6 103.62 5.61 103.71 7.42 103.78 8.94 103.87 11.21 103.94 13.23 104.01 15.45 104.08 17.78 104.30 26.38 1130.00 307598.0 226440.7 103.53 5.62 103.63 7.43 103.70 8.95 103.79 11.22 103.86 13.25 103.94 15.47 104.01 17.80 104.22 26.43 1190.00 307656.7 226437.9 103.31 5.63 103.40 7.44 103.47 8.97 103.56 11.24 103.63 13.27 103.70 15.51 103.77 17.84 103.97 26.49 1230.00 307694.6 226450.1 103.02 5.64 103.12 7.45 103.20 8.98 103.31 11.26 103.39 13.30 103.46 15.54 103.54 17.88 103.74 26.55 1300.00 307751.4 226490.9 100.69 5.65 100.82 7.46 100.92 9.00 101.05 11.29 101.14 13.41 101.19 15.57 101.47 18.45 102.61 26.53 1350.00 307792.5 226519.3 100.53 6.09 100.67 8.07 100.79 9.78 100.93 12.34 101.03 14.90 101.03 18.02 101.39 20.40 102.60 29.55 1385.00 307822.0 226538.3 100.48 6.54 100.59 8.68 100.69 10.56 100.81 13.38 100.92 16.40 101.04 19.47 101.31 21.90 102.58 30.84 1421.18 307853.7 226555.2 100.45 6.54 100.56 8.69 100.64 10.57 100.76 13.40 100.94 16.65 101.04 18.55 101.27 22.08 102.17 29.07 1456.35 307883.0 226574.1 100.40 6.55 100.47 8.70 100.53 10.58 100.59 13.41 100.65 16.82 100.68 18.72 100.71 22.18 101.09 29.10 1472.78 307897.4 226582.0 99.89 6.56 100.04 8.70 100.16 10.59 100.31 13.43 100.47 16.88 100.55 18.84 100.66 22.16 100.89 29.14 1540.00 307956.4 226614.1 99.58 6.56 99.72 8.71 99.83 10.60 99.97 13.44 100.12 16.92 100.19 18.88 100.31 22.13 100.54 29.35 1604.03 308013.3 226643.5 98.75 6.57 98.89 8.73 98.99 10.62 99.14 13.47 99.27 16.90 99.33 18.92 99.46 22.18 99.73 29.59 1622.19 308029.5 226651.8 98.67 6.58 98.81 8.74 98.91 10.63 99.05 13.49 99.18 16.86 99.27 18.96 99.39 22.22 99.68 29.66 1680.00 308081.0 226678.1 98.49 6.59 98.63 8.75 98.73 10.65 98.85 13.51 98.98 16.81 99.05 19.00 99.16 22.27 99.47 29.75 1732.90 308128.1 226702.3 98.25 6.59 98.46 8.76 98.61 10.67 98.78 13.54 98.92 16.73 99.02 19.04 99.13 22.32 99.36 29.83 1820.00 308205.7 226741.8 97.93 6.59 98.22 8.77 98.38 10.68 98.55 13.56 98.68 16.66 98.77 19.07 98.86 22.36 99.06 29.92 1840.00 308223.6 226750.7 97.02 6.60 97.37 8.78 97.55 10.70 97.71 13.58 97.83 16.64 97.91 19.11 98.01 22.41 98.20 30.00 1915.00 308290.7 226784.3 96.61 6.60 96.97 8.78 97.24 10.70 97.55 13.60 97.71 16.59 97.80 19.14 97.88 22.45 98.03 30.03 1930.06 308304.2 226790.9 95.66 6.61 95.80 8.78 95.92 10.70 96.08 13.60 96.24 16.53 96.46 19.14 96.69 22.47 96.82 30.09 1990.00 308358.3 226816.7 95.20 6.61 95.34 8.78 95.47 10.70 95.67 13.59 95.95 16.37 96.29 19.06 96.56 22.49 96.60 30.21 2068.10 308428.8 226850.2 94.89 6.60 95.10 8.75 95.26 10.68 95.54 13.47 95.88 16.14 96.26 18.72 96.53 23.26 96.59 25.94 2080.00 308439.8 226855.0 94.86 6.58 95.09 8.72 95.24 10.66 95.51 13.37 95.81 15.96 96.13 18.53 96.33 21.99 96.40 21.38 2092.46 308451.4 226859.5 94.82 6.58 95.05 8.71 95.20 10.65 95.46 13.37 95.76 15.88 96.09 18.61 96.28 19.93 96.35 21.14 2115.06 308472.7 226866.9 94.75 6.55 94.98 8.67 95.08 10.65 95.21 13.38 95.32 15.89 95.46 18.60 95.56 19.91 95.59 21.16 2209.00 308561.4 226898.0 94.75 6.41 94.98 8.49 95.08 10.44 95.21 13.15 95.32 15.50 95.45 18.12 95.56 19.62 95.60 20.71 2252.00 308601.9 226912.3 94.75 5.91 94.98 7.50 95.08 8.70 95.21 10.37 95.32 11.74 95.46 13.15 95.57 14.53 95.60 14.02 2290.00 308637.9 226924.6 93.99 5.90 94.15 7.29 94.28 8.16 94.42 8.99 94.50 9.64 94.64 10.20 94.69 11.23 94.86 8.96 2300.00 308647.3 226927.9 93.97 6.28 94.13 7.92 94.26 9.15 94.41 10.16 94.49 10.94 94.59 11.68 94.66 12.85 94.85 10.22 2313.99 308660.2 226933.2 93.95 7.21 94.11 9.33 94.25 11.18 94.40 13.27 94.48 14.97 94.58 16.44 94.65 18.01 94.84 20.26 2320.00 308664.6 226937.2 93.93 8.14 94.09 10.75 94.23 13.20 94.38 16.38 94.46 18.97 94.57 21.32 94.64 23.05 94.82 30.24


50% AEP 20%


AEP 0.1% AEP

Chainage X Y Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s)

Tallaght Stream Main Channel_Present Day (cont'd) 2390.00 308724.4 226973.2 93.71 8.15 93.86 10.76 94.01 13.20 94.16 16.39 94.25 18.82 94.37 21.71 94.45 23.98 94.63 31.58 2450.00 308776.9 227002.4 93.41 8.16 93.58 10.77 93.76 13.19 93.94 16.38 94.03 18.66 94.13 22.07 94.21 24.91 94.34 32.97 2488.22 308812.4 227016.3 93.35 8.16 93.52 10.78 93.70 13.18 93.89 16.23 93.99 18.31 94.10 21.19 94.18 23.58 94.33 29.61 2502.66 308825.4 227022.5 93.33 8.16 93.46 10.78 93.57 13.18 93.67 16.12 93.75 17.99 93.83 20.34 93.90 22.27 94.04 26.18 2530.00 308848.6 227037.1 93.32 8.17 93.45 10.79 93.55 13.17 93.65 16.18 93.72 18.24 93.80 20.96 93.86 23.17 93.95 28.82 2542.85 308859.7 227043.4 93.32 8.15 93.45 10.61 93.56 12.87 93.68 15.70 93.75 17.79 93.83 20.47 93.90 22.84 94.02 28.58 2590.00 308898.9 227069.1 91.66 8.15 91.82 10.62 91.94 12.86 92.06 15.44 92.13 17.19 92.21 19.31 92.28 21.36 92.53 26.12 2660.00 308959.9 227103.3 91.32 8.17 91.47 10.83 91.58 13.13 91.70 15.71 91.77 17.28 91.86 19.24 91.93 21.10 92.24 26.57 2696.15 308988.6 227125.4 90.85 8.17 90.99 10.84 91.11 13.15 91.22 15.73 91.28 17.30 91.36 19.27 91.43 21.13 91.62 26.63 2699.80 308991.5 227127.6 90.78 8.18 90.93 10.84 91.04 13.15 91.15 15.73 91.22 17.31 91.29 19.28 91.36 21.15 91.55 26.65 2730.00 309018.8 227139.6 90.55 8.18 90.69 10.85 90.80 13.17 90.90 15.75 90.96 17.33 91.04 19.30 91.10 21.18 91.30 26.70 2790.00 309064.2 227178.8 90.13 8.19 90.28 10.87 90.39 13.19 90.50 15.78 90.57 17.36 90.65 19.35 90.72 21.23 90.98 26.78 2832.10 309095.2 227207.0 89.81 8.48 89.97 11.30 90.09 13.73 90.21 16.52 90.29 18.35 90.38 20.50 90.45 22.59 90.73 28.85 2840.00 309100.8 227212.7 89.79 8.75 89.94 11.72 90.06 14.28 90.18 17.25 90.26 19.32 90.34 21.65 90.43 23.93 90.75 30.88 2870.00 309125.5 227229.6 89.23 9.80 89.48 11.86 89.68 14.28 89.90 17.26 90.07 19.32 90.24 21.65 90.39 23.95 90.73 31.44 2910.00 309154.8 227256.8 89.19 9.89 89.47 12.00 89.67 14.39 89.90 17.32 90.06 19.32 90.20 21.65 90.35 24.01 90.72 30.80 2920.00 309162.3 227263.4 89.16 8.89 89.41 11.92 89.60 14.46 89.82 17.40 89.98 19.82 90.14 22.00 90.30 24.11 90.65 28.54 2980.00 309201.0 227309.2 88.87 8.81 89.01 11.81 89.29 14.09 89.59 17.12 89.74 19.28 89.89 21.63 90.10 24.15 90.38 27.47 3010.00 309221.0 227331.5 88.87 8.80 89.01 11.77 89.29 13.49 89.59 16.76 89.74 18.89 89.89 21.10 90.10 23.78 90.38 26.83 3047.06 309252.0 227351.2 88.31 8.80 88.84 11.73 89.22 13.19 89.46 16.85 89.58 19.24 89.69 21.05 89.83 23.85 90.04 26.43 3050.83 309255.5 227352.5 88.30 8.81 88.81 11.70 89.21 13.16 89.45 16.85 89.56 19.25 89.67 21.09 89.81 23.87 90.01 26.48 3090.00 309286.0 227376.7 88.27 8.82 88.80 11.68 89.20 13.16 89.44 16.72 89.56 18.84 89.67 20.81 89.81 23.46 90.01 26.34 3110.71 309301.1 227390.8 88.25 8.84 88.79 11.67 89.19 13.17 89.43 16.76 89.54 18.89 89.65 20.88 89.79 23.52 89.99 26.46 3165.26 309351.6 227411.1 87.48 8.87 87.64 11.70 87.71 13.21 87.88 16.83 87.97 18.97 88.05 20.98 88.17 23.63 88.51 26.64 3220.00 309402.8 227430.5 87.19 8.90 87.35 11.76 87.43 13.27 87.60 16.92 87.69 19.09 87.78 21.13 87.91 23.83 88.36 29.23 3320.00 309498.3 227460.2 86.74 8.95 86.92 11.83 87.00 13.36 87.19 17.04 87.29 19.24 87.37 21.32 87.55 24.90 87.98 36.76 3420.00 309595.6 227483.4 86.38 9.00 86.55 11.90 86.64 13.45 86.82 17.15 86.92 19.39 87.00 21.52 87.14 25.93 87.46 41.84 3471.01 309645.9 227491.8 86.06 9.03 86.23 11.94 86.32 13.50 86.50 17.23 86.61 19.48 86.69 21.63 86.84 26.02 87.21 40.37 3474.70 309649.5 227492.3 86.02 9.06 86.19 11.97 86.27 13.54 86.45 17.28 86.54 19.55 86.62 21.72 86.77 26.09 87.13 38.80 3570.00 309744.3 227502.9 85.10 9.10 85.28 12.03 85.37 13.63 85.55 17.39 85.65 19.69 85.75 21.89 85.91 26.27 86.17 37.68 3700.00 309874.2 227505.4 84.04 9.17 84.22 12.13 84.31 13.74 84.50 17.55 84.60 19.89 84.69 22.14 84.86 26.52 85.05 35.68 3800.00 309974.1 227501.0 83.19 9.23 83.37 12.21 83.46 13.84 83.65 17.69 83.75 20.06 83.84 22.36 84.00 26.75 84.15 33.23 3880.00 310053.5 227491.7 82.37 9.28 82.54 12.28 82.62 13.93 82.80 17.81 82.90 20.22 82.98 22.56 83.13 26.96 83.29 31.89 3980.00 310152.5 227479.1 81.52 9.33 81.66 12.35 81.73 14.02 81.88 17.93 81.97 20.37 82.05 22.75 82.18 27.15 82.31 32.23 4040.00 310211.6 227489.5 80.66 9.36 80.79 12.40 80.85 14.08 80.99 18.02 81.06 20.48 81.14 22.89 81.25 27.30 81.39 32.50 4064.58 310235.7 227494.4 78.91 9.39 79.06 12.43 79.14 14.12 79.31 18.07 79.41 20.54 79.50 22.97 79.66 27.39 79.83 32.63 4100.00 310270.8 227498.5 78.74 9.40 78.88 12.45 78.95 14.15 79.10 18.11 79.19 20.59 79.28 23.03 79.41 27.45 79.56 32.74 4130.00 310300.8 227500.0 78.43 9.42 78.58 12.48 78.66 14.18 78.82 18.15 78.92 20.65 79.00 23.10 79.14 27.52 79.30 32.86 4170.00 310340.5 227504.2 78.18 9.44 78.33 12.51 78.41 14.22 78.57 18.20 78.67 20.71 78.75 23.18 78.89 27.60 79.05 32.99 4200.00 310369.8 227510.7 77.85 9.46 78.00 12.53 78.08 14.25 78.24 18.24 78.34 20.77 78.42 23.25 78.56 27.68 78.73 33.11 4230.00 310399.0 227517.3 77.58 9.48 77.73 12.55 77.81 14.28 77.97 18.28 78.06 20.81 78.15 23.31 78.28 27.74 78.44 33.22 4250.00 310419.0 227516.0 77.47 9.50 77.62 12.59 77.69 14.32 77.84 18.34 77.93 20.89 78.02 23.40 78.15 27.83 78.30 33.38 4350.00 310514.9 227539.5 76.47 9.55 76.64 12.66 76.73 14.40 76.91 18.46 77.02 21.03 77.11 23.58 77.27 28.02 77.46 33.70 4470.00 310628.1 227579.3 75.36 9.60 75.54 12.73 75.64 14.50 75.85 18.59 75.97 21.20 76.09 23.80 76.30 28.23 76.58 34.07


50% AEP 20%


AEP 0.1% AEP


Tallaght Stream Main Channel_Present Day (cont'd) 4531.99 310686.3 227600.8 75.08 9.64 75.26 12.78 75.35 14.56 75.56 18.68 75.68 21.31 75.81 23.94 76.03 28.37 76.33 34.31 4548.02 310701.2 227606.7 74.73 9.66 74.88 12.81 74.96 14.60 75.12 18.72 75.21 21.37 75.30 24.01 75.44 28.44 75.67 34.42 4580.00 310730.9 227618.4 74.26 9.67 74.43 12.84 74.51 14.63 74.67 18.76 74.76 21.42 74.85 24.08 74.97 28.52 75.31 37.73 4630.00 310779.2 227630.8 73.60 9.70 73.80 12.87 73.89 14.67 74.06 18.83 74.17 21.50 74.30 24.17 74.42 28.62 74.79 41.02 4680.00 310828.5 227626.6 72.91 9.73 73.12 12.91 73.22 14.72 73.38 18.89 73.51 21.58 73.72 24.28 73.83 28.72 74.30 41.11 4720.00 310867.7 227619.2 72.60 9.75 72.78 12.93 72.84 14.75 72.91 18.93 73.07 21.64 73.48 24.35 73.50 28.80 74.15 41.21 4737.00 310884.0 227614.3 72.50 9.75 72.65 12.94 72.70 14.76 72.72 18.95 72.90 21.64 73.40 24.35 73.40 28.82 74.10 41.24

Tallaght Stream Side Channel_Present Day 0.00 308568.3 226402.0 97.98 2.30 98.07 3.03 98.14 3.58 98.23 4.41 98.30 5.14 98.38 5.96 98.47 6.91 98.69 9.71 5.72 308567.3 226407.6 97.93 2.30 98.02 3.03 98.09 3.58 98.18 4.41 98.25 5.14 98.33 5.96 98.42 6.91 98.63 9.71 40.00 308554.1 226438.6 97.59 2.30 97.68 3.03 97.74 3.58 97.82 4.41 97.89 5.13 97.96 5.96 98.04 6.91 98.20 9.71 100.00 308537.0 226494.2 96.92 2.30 97.02 3.03 97.08 3.58 97.17 4.41 97.23 5.13 97.32 5.96 97.43 6.91 97.56 9.71 180.00 308601.7 226536.5 96.62 2.30 96.70 3.02 96.75 3.58 96.82 4.41 96.88 5.13 96.94 5.96 97.00 6.91 97.14 9.58 360.00 308610.4 226712.1 94.96 2.30 95.06 3.02 95.13 3.58 95.22 4.40 95.30 5.12 95.37 5.95 95.49 6.89 95.68 9.41 450.00 308632.8 226799.1 94.34 2.29 94.44 3.01 94.55 3.57 94.75 4.38 94.87 5.07 94.99 5.90 95.09 6.84 95.37 9.34 560.00 308641.3 226907.3 94.00 2.28 94.17 2.98 94.33 3.82 94.52 5.28 94.63 6.53 94.74 8.01 94.83 9.47 95.00 15.37 595.00 308662.2 226935.0 93.95 2.27 94.11 2.96 94.25 4.07 94.40 6.21 94.48 6.53 94.58 8.01 94.65 9.47 94.84 15.37


Water Surface ProfilesTallaght Stream Main Channel - Present Day Scenario

70.00

75.00

80.00

85.00

90.00

95.00

100.00

105.00

110.00

0.00

270.0

036

0.00

709.

4510

50.0

011

30.00

1300

.00

1421

.18

1540

.0016

80.0

018

40.0

0199

0.00

2092

.46

2252

.00

2313

.99

2450.0

025

30.0

026

60.0

0273

0.00

2840

.00

2920

.00

3047

.06

3110

.7133

20.0

034

74.7

038

00.00

4040

.00

4130

.00

4230

.0044

70.0

045

80.0

047

20.00

Chainage

Max

H

50% AEP Max H20% AEP Max H10% AEP Max H4% AEP Max H2% AEP Max H1% AEP Max H0.5% AEP Max H0.1% AEP Max H


Owendoher Stream

50% AEP 20% AEP 10% AEP 4% AEP 2% AEP 1% AEP 0.5% AEP 0.1% AEP Chainage X Y Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q Max H Max Q

(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Owendoher Stream_Present Day

0.00 313582.3 225515.0 109.97 14.10 110.14 18.32 110.25 21.39 110.38 25.82 110.49 29.58 110.59 33.80 110.70 38.53 110.97 52.00 10.27 313572.3 225517.5 109.81 14.10 109.98 18.32 110.09 21.39 110.22 25.82 110.33 29.58 110.43 33.80 110.54 38.53 110.82 52.00 37.92 313553.2 225533.1 109.13 14.10 109.33 18.32 109.47 21.39 109.61 25.82 109.74 29.58 109.84 33.80 109.96 38.53 110.26 52.00 41.55 313553.3 225536.7 109.07 14.10 109.26 18.32 109.40 21.39 109.54 25.82 109.67 29.58 109.78 33.80 109.90 38.53 110.20 52.00 126.72 313555.5 225618.5 107.63 14.10 107.81 18.32 107.94 21.39 108.11 25.82 108.30 29.58 108.43 33.80 108.59 38.53 109.04 52.00 128.56 313554.9 225620.3 107.61 14.10 107.79 18.32 107.92 21.39 108.09 25.82 108.27 29.58 108.41 33.80 108.57 38.53 109.02 52.00 130.40 313554.3 225622.0 107.60 14.10 107.78 18.32 107.90 21.39 108.07 25.82 108.24 29.58 108.37 33.80 108.51 38.53 108.93 52.00 162.70 313543.4 225652.4 107.24 14.10 107.43 18.32 107.56 21.39 107.74 25.82 107.87 29.58 108.02 33.80 108.19 38.53 108.66 52.00 164.71 313543.0 225654.3 107.23 14.10 107.42 18.32 107.55 21.39 107.73 25.82 107.87 29.58 108.02 33.80 108.19 38.53 108.65 52.00 166.73 313542.8 225656.3 107.21 14.10 107.40 18.32 107.53 21.39 107.71 25.82 107.84 29.58 107.99 33.80 108.15 38.53 108.57 52.00 270.00 313527.3 225758.4 106.35 14.10 106.50 18.32 106.60 21.39 106.73 25.82 106.84 29.58 106.95 33.80 107.07 38.53 107.37 52.00 313.89 313520.2 225801.7 105.52 14.10 105.62 18.32 105.68 21.39 105.78 25.82 105.86 29.58 105.96 33.80 106.05 38.53 106.26 52.00 315.63 313520.0 225803.4 105.32 14.10 105.44 18.32 105.52 21.39 105.62 25.82 105.71 29.58 105.82 33.80 105.92 38.53 106.13 52.00 340.00 313524.0 225827.5 105.24 14.10 105.34 18.32 105.41 21.39 105.50 25.82 105.58 29.58 105.68 33.80 105.76 38.53 105.92 52.00 369.60 313516.6 225852.9 104.91 14.10 104.98 18.32 105.02 21.39 105.08 25.82 105.14 29.58 105.20 33.80 105.25 38.53 105.38 52.00 371.59 313514.7 225853.3 104.91 14.10 104.97 18.32 105.01 21.39 105.07 25.82 105.13 29.58 105.18 33.80 105.24 38.53 105.37 52.00 410.00 313488.4 225872.5 97.27 14.10 97.38 18.32 97.45 21.39 97.55 25.82 97.62 29.58 97.82 33.80 97.90 38.53 98.07 52.00 430.00 313473.1 225884.6 96.02 14.10 96.15 18.32 96.23 21.39 96.34 25.82 96.43 29.58 96.52 33.80 96.68 38.53 96.95 52.00 510.00 313479.6 225953.9 94.37 14.10 94.49 18.32 94.56 21.39 94.66 25.82 94.74 29.58 94.83 33.80 94.92 38.53 95.15 52.00 640.00 313492.6 226079.8 92.56 14.10 92.69 18.32 92.78 21.39 92.88 25.82 92.96 29.58 93.04 33.80 93.13 38.53 93.37 52.00 890.00 313563.3 226304.4 87.27 14.10 87.44 18.32 87.55 21.39 87.69 25.82 87.81 29.58 87.93 33.80 88.07 38.53 88.39 52.00 1050.00 313625.9 226437.5 84.62 14.10 84.76 18.32 84.85 21.39 84.96 25.82 85.06 29.58 85.15 33.80 85.26 38.53 85.51 52.00 1120.00 313627.4 226506.9 83.80 14.10 83.94 18.32 84.04 21.39 84.16 25.82 84.26 29.58 84.36 33.80 84.46 38.52 84.72 51.99 1218.52 313639.3 226603.6 82.72 14.10 82.85 18.32 82.93 21.39 83.05 25.82 83.14 29.58 83.23 33.80 83.33 38.52 83.58 51.99 1224.53 313638.1 226609.5 82.65 14.10 82.77 18.32 82.86 21.39 82.97 25.82 83.06 29.58 83.16 33.80 83.25 38.53 83.49 51.99 1230.54 313636.9 226615.4 82.63 14.10 82.76 18.32 82.84 21.39 82.95 25.82 83.05 29.58 83.14 33.80 83.23 38.53 83.47 51.99 1300.00 313636.1 226683.7 81.87 14.10 82.02 18.32 82.10 21.39 82.22 25.82 82.32 29.58 82.41 33.80 82.51 38.53 82.77 51.99 1350.00 313612.3 226727.6 81.51 14.10 81.61 18.32 81.68 21.39 81.78 25.82 81.86 29.58 81.94 33.80 82.04 38.52 82.25 51.21 1500.00 313597.5 226873.9 76.83 14.10 77.14 18.31 77.36 21.38 77.68 25.81 77.96 29.57 78.26 33.79 78.43 37.28 78.43 43.23 1538.72 313598.3 226912.5 74.46 14.09 74.60 18.31 74.69 21.38 74.82 25.81 74.92 29.56 75.03 33.77 75.09 36.08 75.10 36.16 1560.44 313592.2 226933.2 73.99 14.09 74.15 18.31 74.26 21.38 74.41 25.81 74.53 29.56 74.66 33.77 74.73 36.10 74.73 36.28 1566.47 313589.9 226938.8 73.89 14.09 74.05 18.31 74.16 21.38 74.31 25.81 74.43 29.56 74.56 33.77 74.62 36.10 74.63 36.28 1572.50 313587.6 226944.4 73.86 14.09 74.02 18.31 74.13 21.38 74.28 25.81 74.40 29.56 74.52 33.77 74.59 36.10 74.60 36.28 1585.00 313583.4 226956.1 73.85 14.09 74.01 18.31 74.12 21.38 74.27 25.81 74.38 29.56 74.51 33.77 74.58 36.10 74.59 36.41 1602.28 313580.9 226973.2 72.67 14.09 72.81 18.31 72.90 21.38 73.03 25.81 73.13 29.56 73.24 33.78 73.31 36.11 73.45 37.17 1650.00 313574.8 227020.5 72.29 14.09 72.46 18.31 72.58 21.38 72.73 25.81 72.85 29.56 72.98 33.77 73.07 36.44 73.30 40.87 1694.18 313569.2 227064.4 70.74 14.09 70.87 18.31 70.96 21.38 71.10 25.81 71.22 29.56 71.35 33.77 71.45 36.79 71.71 44.35 1709.80 313567.7 227079.9 70.51 14.09 70.66 18.31 70.77 21.38 70.93 25.81 71.07 29.56 71.21 33.77 71.32 36.82 71.61 44.77 1726.86 313574.2 227095.4 70.28 14.09 70.47 18.31 70.61 21.38 70.79 25.81 70.94 29.56 71.10 33.77 71.22 36.82 71.52 44.81 1732.00 313577.2 227099.6 70.22 14.09 70.43 18.31 70.57 21.38 70.75 25.81 70.91 29.56 71.07 33.77 71.19 36.83 71.49 44.98 1745.00 313584.7 227110.2 69.40 14.09 69.54 18.31 69.62 21.38 69.74 25.81 69.83 29.56 69.93 33.77 69.99 36.84 70.17 45.35 1760.00 313593.3 227122.4 69.13 14.09 69.28 18.31 69.37 21.38 69.49 25.81 69.59 29.56 69.69 33.77 69.76 36.84 69.94 45.57 1797.32 313614.9 227152.9 68.75 14.09 68.88 18.31 68.97 21.38 69.08 25.81 69.17 29.56 69.26 33.77 69.33 36.84 69.50 45.59 1808.56 313621.4 227162.1 68.61 14.09 68.74 18.31 68.82 21.38 68.93 25.81 69.02 29.56 69.10 33.77 69.16 36.84 69.32 45.59



(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Owendoher Stream_Present Day (cont’d)

1882.54 313664.7 227221.5 67.83 14.09 67.97 18.31 68.06 21.38 68.18 25.81 68.27 29.56 68.35 33.77 68.41 36.84 68.58 45.59 1886.82 313666.5 227225.4 67.77 14.09 67.90 18.31 67.99 21.38 68.11 25.81 68.20 29.56 68.28 33.77 68.34 36.84 68.50 45.59 1930.00 313685.1 227264.4 67.20 14.09 67.33 18.31 67.41 21.38 67.52 25.81 67.61 29.56 67.69 33.77 67.76 36.84 67.94 45.59 2012.77 313712.3 227342.4 66.12 14.09 66.24 18.31 66.32 21.38 66.44 25.81 66.53 29.56 66.63 33.77 66.71 36.84 66.92 45.59 2018.49 313714.2 227347.7 66.08 14.09 66.20 18.31 66.28 21.38 66.40 25.81 66.49 29.56 66.59 33.77 66.66 36.84 66.88 45.59 2024.21 313716.1 227353.1 65.98 14.09 66.11 18.31 66.19 21.38 66.31 25.81 66.40 29.56 66.50 33.77 66.58 36.85 66.80 45.68 2070.00 313734.0 227395.2 65.48 14.09 65.62 18.31 65.71 21.38 65.82 25.81 65.92 29.56 66.02 33.77 66.11 37.30 66.35 47.76 2115.42 313756.9 227434.4 64.91 14.09 65.05 18.31 65.15 21.38 65.27 25.81 65.38 29.56 65.48 33.77 65.58 37.77 65.89 50.21 2125.14 313760.4 227443.5 64.87 14.09 65.01 18.31 65.10 21.38 65.23 25.81 65.33 29.56 65.43 33.77 65.53 37.79 65.84 50.68 2135.86 313764.7 227453.3 64.76 14.09 64.89 18.31 64.97 21.38 65.09 25.81 65.18 29.56 65.28 33.77 65.38 37.79 65.67 50.68 2157.36 313775.6 227471.8 64.05 14.09 64.14 18.31 64.20 21.38 64.29 25.81 64.36 29.56 64.45 33.77 64.53 37.79 64.83 50.68 2200.00 313805.9 227500.9 61.21 14.09 61.46 18.31 61.63 21.38 61.88 25.81 62.14 29.56 62.41 33.77 62.68 37.78 63.42 50.68 2272.31 313848.2 227559.4 59.25 14.09 59.38 18.31 59.47 21.38 59.59 25.81 59.68 29.56 59.79 33.77 59.88 37.77 60.16 50.68 2281.30 313853.9 227566.4 59.19 14.09 59.32 18.31 59.41 21.38 59.53 25.81 59.63 29.56 59.73 33.77 59.82 37.77 60.11 50.68 2290.28 313859.6 227573.3 59.11 14.09 59.24 18.31 59.33 21.38 59.45 25.81 59.55 29.56 59.65 33.77 59.75 37.77 60.03 50.68 2320.00 313876.9 227597.4 58.84 14.09 58.98 18.31 59.07 21.38 59.20 25.81 59.30 29.56 59.40 33.77 59.49 37.77 59.78 50.79 2390.00 313923.8 227648.8 58.00 14.09 58.15 18.31 58.24 21.38 58.37 25.81 58.47 29.56 58.57 33.77 58.67 37.77 58.96 51.06 2535.24 313998.5 227768.0 56.20 14.09 56.34 18.31 56.43 21.38 56.55 25.81 56.64 29.56 56.75 33.77 56.84 37.77 57.14 51.23 2539.36 313999.5 227772.0 56.18 14.09 56.32 18.31 56.40 21.38 56.52 25.81 56.61 29.56 56.71 33.77 56.81 37.77 57.09 51.24 2543.47 314000.6 227775.9 56.15 14.09 56.29 18.31 56.37 21.38 56.49 25.81 56.58 29.56 56.68 33.77 56.77 37.77 57.05 51.26 2610.00 314015.3 227840.7 55.41 14.09 55.57 18.31 55.67 21.38 55.81 25.80 55.92 29.56 56.04 33.77 56.15 37.76 56.50 51.27 2677.73 314032.8 227905.9 54.65 14.09 54.82 18.31 54.93 21.38 55.08 25.80 55.20 29.56 55.33 33.77 55.45 37.76 55.84 51.46 2679.91 314033.3 227908.0 54.64 14.09 54.80 18.31 54.91 21.38 55.07 25.80 55.19 29.56 55.32 33.77 55.43 37.76 55.82 51.66 2682.09 314033.9 227910.1 54.62 14.09 54.79 18.31 54.90 21.38 55.05 25.80 55.17 29.56 55.30 33.77 55.42 37.76 55.80 51.66 2721.04 314044.7 227947.5 54.42 14.09 54.58 18.31 54.69 21.38 54.84 25.80 54.96 29.56 55.08 33.77 55.20 37.76 55.57 51.66 2725.34 314045.9 227951.7 54.38 14.09 54.55 18.31 54.66 21.38 54.80 25.80 54.92 29.56 55.05 33.77 55.16 37.76 55.55 51.66 2729.63 314047.1 227955.8 54.37 14.09 54.53 18.31 54.64 21.38 54.79 25.80 54.91 29.56 55.03 33.77 55.15 37.76 55.53 51.66 2767.82 314057.6 227992.5 54.09 14.09 54.25 18.31 54.36 21.38 54.50 25.80 54.61 29.56 54.73 33.77 54.84 37.76 55.21 51.65 2769.97 314058.2 227994.6 54.07 14.09 54.24 18.31 54.34 21.38 54.48 25.80 54.60 29.56 54.72 33.77 54.83 37.76 55.19 51.65 2772.11 314058.8 227996.6 54.07 14.09 54.23 18.31 54.33 21.38 54.48 25.80 54.59 29.56 54.71 33.77 54.82 37.76 55.18 51.65 2865.57 314086.8 228085.6 52.97 14.09 53.12 18.31 53.22 21.38 53.36 25.80 53.47 29.56 53.59 33.77 53.70 37.76 54.07 51.64 2871.58 314088.4 228091.4 52.91 14.09 53.06 18.31 53.17 21.38 53.31 25.80 53.42 29.56 53.54 33.77 53.65 37.75 54.02 51.64 2888.70 314094.3 228107.4 52.84 14.09 53.00 18.31 53.10 21.38 53.25 25.80 53.36 29.56 53.49 33.77 53.60 37.75 53.97 51.64 2890.53 314095.1 228109.1 52.83 14.09 52.98 18.31 53.09 21.38 53.23 25.80 53.34 29.56 53.47 33.77 53.58 37.75 53.95 51.64 2896.00 314097.5 228114.0 52.81 14.09 52.96 18.31 53.07 21.38 53.21 25.80 53.33 29.56 53.45 33.77 53.56 37.75 53.94 51.64 2961.49 314116.9 228176.4 52.07 14.09 52.22 18.31 52.32 21.38 52.46 25.80 52.57 29.56 52.68 33.77 52.79 37.76 53.14 51.64 2968.45 314119.1 228183.0 51.97 14.09 52.11 18.31 52.21 21.38 52.34 25.80 52.44 29.56 52.55 33.77 52.64 37.76 52.96 51.64 2975.41 314121.3 228189.6 51.93 14.09 52.07 18.31 52.17 21.38 52.30 25.80 52.40 29.56 52.51 33.77 52.60 37.76 52.92 51.64 3053.38 314154.9 228259.0 50.88 14.09 50.96 18.31 51.02 21.38 51.10 25.80 51.17 29.56 51.24 33.77 51.31 37.76 51.58 51.64 3055.45 314156.2 228260.6 50.83 14.09 50.91 18.31 50.96 21.38 51.04 25.80 51.10 29.56 51.18 33.77 51.25 37.76 51.52 51.64 3057.51 314157.4 228262.2 50.77 14.09 50.85 18.31 50.90 21.38 50.98 25.80 51.05 29.56 51.13 33.77 51.20 37.76 51.48 51.64 3070.00 314165.2 228272.1 50.12 14.09 50.26 18.31 50.35 21.38 50.48 25.80 50.59 29.56 50.70 33.77 50.81 37.76 51.19 51.64 3093.37 314180.9 228289.3 49.81 14.09 49.94 18.31 50.03 21.38 50.16 25.80 50.27 29.56 50.39 33.77 50.51 37.75 50.93 51.63 3094.49 314181.7 228290.1 49.79 14.09 49.92 18.31 50.01 21.38 50.14 25.80 50.25 29.56 50.38 33.77 50.50 37.75 50.92 51.63



(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Owendoher Stream_Present Day (cont’d)

3095.60 314182.5 228290.9 49.78 14.09 49.91 18.31 50.00 21.38 50.14 25.80 50.25 29.56 50.37 33.77 50.49 37.75 50.92 51.63 3150.00 314213.9 228335.1 48.78 14.09 48.98 18.31 49.13 21.38 49.34 25.80 49.51 29.56 49.70 33.77 49.88 37.74 50.48 51.62 3160.00 314218.8 228343.8 48.99 17.16 49.29 21.46 49.52 25.25 49.86 30.80 50.16 35.56 50.50 40.99 50.90 47.14 51.90 64.60 3200.99 314227.5 228383.9 48.93 21.00 49.24 26.63 49.48 31.47 49.82 38.64 50.11 44.82 50.45 51.94 50.83 60.06 51.80 82.50 3235.95 314233.6 228418.3 48.86 21.00 49.17 26.63 49.40 31.47 49.73 38.64 50.01 44.82 50.31 51.94 50.63 60.06 51.42 81.50 3250.00 314235.6 228432.2 48.90 21.00 49.21 26.63 49.44 31.47 49.78 38.64 50.08 44.82 50.42 51.94 50.80 60.06 51.82 81.37 3300.00 314245.3 228481.2 47.80 21.00 48.15 26.62 48.42 31.46 48.82 38.64 49.13 44.82 49.43 51.94 49.74 60.06 50.30 79.90 3308.00 314246.2 228489.1 47.72 21.00 48.06 26.62 48.33 31.46 48.72 38.64 49.02 44.81 49.31 51.93 49.61 60.06 50.14 78.55 3321.68 314247.1 228502.8 47.13 21.00 47.33 26.62 47.49 31.46 47.70 38.64 47.87 44.81 48.05 51.93 48.24 60.06 48.64 78.95 3325.20 314246.6 228506.2 47.13 21.00 47.33 26.62 47.49 31.46 47.69 38.64 47.86 44.81 48.02 51.93 48.22 60.06 48.61 79.35 3340.00 314243.1 228520.6 47.16 21.00 47.38 26.62 47.56 31.46 47.80 38.64 48.00 44.81 48.22 51.93 48.45 60.06 48.93 79.35 3354.77 314235.4 228533.0 45.91 21.00 46.07 26.62 46.19 31.46 46.36 38.64 46.48 44.81 46.62 51.93 46.77 60.06 47.11 79.68 3380.00 314217.8 228551.1 45.62 21.00 45.74 26.62 45.84 31.46 45.96 38.64 46.07 44.81 46.18 51.93 46.30 60.06 46.60 80.37 3440.00 314201.0 228597.4 44.88 21.00 45.03 26.62 45.15 31.46 45.29 38.64 45.41 44.81 45.54 51.93 45.69 60.06 46.02 80.72 3500.00 314256.5 228611.5 44.06 21.00 44.21 26.62 44.32 31.46 44.48 38.63 44.61 44.81 44.75 51.93 44.91 60.06 45.31 80.72 3550.00 314303.4 228626.8 43.56 21.00 43.71 26.62 43.83 31.46 44.00 38.63 44.15 44.81 44.31 51.93 44.49 60.06 44.95 81.13 3650.00 314297.6 228725.2 42.59 21.00 42.80 26.62 42.96 31.46 43.19 38.63 43.37 44.81 43.58 51.93 43.80 60.05 44.37 81.97 3740.00 314282.6 228813.4 41.94 20.99 42.18 26.62 42.37 31.46 42.65 38.63 42.88 44.81 43.13 51.92 43.41 60.05 44.16 82.39 3771.86 314266.7 228841.0 41.83 20.99 42.08 26.62 42.28 31.46 42.56 38.63 42.80 44.80 43.06 51.92 43.34 60.04 44.07 82.38 3790.00 314257.7 228856.8 41.83 20.99 42.08 26.62 42.29 31.46 42.58 38.63 42.82 44.80 43.09 51.92 43.38 60.04 44.13 82.38 3796.43 314254.3 228862.2 39.46 20.99 39.63 26.62 39.77 31.46 39.95 38.63 40.09 44.80 40.24 51.92 40.40 60.04 40.80 82.38 3850.00 314217.3 228900.7 39.09 20.99 39.24 26.62 39.36 31.46 39.53 38.63 39.66 44.80 39.79 51.92 39.94 60.04 40.33 82.38 3940.00 314155.3 228965.0 38.31 20.99 38.46 26.62 38.59 31.46 38.79 38.63 38.92 44.80 39.05 51.92 39.20 60.04 39.64 82.38 4014.66 314112.9 229025.2 37.85 20.99 37.99 26.62 38.13 31.46 38.36 38.63 38.49 44.80 38.62 51.92 38.76 60.04 39.26 82.38 4021.13 314108.8 229030.2 37.84 20.99 37.98 26.62 38.12 31.46 38.35 38.63 38.48 44.80 38.61 51.92 38.74 60.04 39.25 82.38 4027.59 314104.7 229035.1 37.80 20.99 37.93 26.62 38.08 31.46 38.32 38.63 38.44 44.80 38.57 51.92 38.70 60.04 39.21 82.38 4045.99 314091.4 229047.8 37.78 20.99 37.92 26.62 38.08 31.46 38.33 38.63 38.45 44.80 38.55 51.92 38.65 60.04 39.11 82.38 4080.00 314063.9 229067.8 37.64 20.99 37.77 26.62 37.94 31.46 38.22 38.63 38.32 44.80 38.42 51.92 38.50 60.04 39.00 82.38


Water Surface Profiles Owendoher Stream - Present Day Scenario

35.00

45.00

55.00

65.00

75.00

85.00

95.00

105.00

115.00

0.00 500.00 1000.00 1500.00 2000.00 2500.00 3000.00 3500.00 4000.00 4500.00

Chainage

Ma

x H

50% AEP Max H

20% AEP Max H

10% AEP Max H

4% AEP Max H

2% AEP Max H

1% AEP Max H

0.5% AEP Max H

0.1% AEP Max H


Whitechurch Stream


(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Whitechurch Stream_Present Day

0.00 314799.7 225480.8 111.96 5.22 112.06 6.37 112.17 7.67 112.32 9.67 112.48 11.45 112.64 13.54 112.75 15.97 113.14 23.38 40.37 314783.7 225511.9 110.47 5.22 110.56 6.37 110.66 7.67 110.76 9.67 110.85 11.45 110.95 13.54 111.09 15.97 111.38 23.37 58.09 314786.0 225529.0 110.12 5.22 110.18 6.37 110.24 7.67 110.32 9.67 110.39 11.45 110.47 13.54 110.56 15.97 110.80 23.37 60.00 314785.9 225530.9 110.06 5.22 110.11 6.37 110.17 7.67 110.25 9.67 110.31 11.45 110.39 13.54 110.47 15.97 110.71 23.37 62.95 314785.2 225533.7 109.98 5.22 110.03 6.37 110.09 7.67 110.17 9.67 110.23 11.45 110.31 13.54 110.39 15.97 110.63 23.37 100.00 314776.6 225569.8 109.20 5.22 109.26 6.37 109.33 7.67 109.42 9.67 109.50 11.45 109.61 13.53 109.71 15.97 109.99 23.37 165.00 314769.6 225631.4 107.93 5.22 108.01 6.37 108.10 7.67 108.22 9.67 108.33 11.45 108.44 13.53 108.55 15.97 108.94 23.37 170.00 314766.4 225635.2 107.88 5.22 107.95 6.37 108.03 7.67 108.14 9.67 108.23 11.45 108.33 13.53 108.43 15.97 108.78 23.37 175.00 314763.9 225639.5 107.81 5.22 107.88 6.37 107.96 7.67 108.07 9.67 108.16 11.45 108.25 13.53 108.35 15.97 108.59 23.37 210.00 314752.0 225672.4 106.61 5.22 106.68 6.37 106.75 7.67 106.84 9.67 106.92 11.45 107.00 13.53 107.09 15.97 107.28 23.37 260.00 314726.2 225713.7 106.01 5.22 106.06 6.37 106.11 7.67 106.18 9.66 106.25 11.44 106.31 13.53 106.37 15.97 106.50 23.37 320.00 314673.2 225722.2 104.80 5.22 104.88 6.37 104.94 7.67 105.04 9.66 105.14 11.44 105.24 13.53 105.30 15.96 105.38 23.37 370.00 314675.7 225761.4 103.84 5.22 103.91 6.37 103.98 7.67 104.07 9.66 104.15 11.45 104.24 13.53 104.32 15.96 104.54 23.37 420.00 314682.8 225807.1 102.96 5.22 103.03 6.37 103.10 7.67 103.19 9.66 103.28 11.45 103.37 13.53 103.46 15.96 103.72 23.37 463.61 314687.9 225833.0 102.24 5.21 102.32 6.37 102.40 7.67 102.50 9.66 102.59 11.45 102.68 13.53 102.77 15.96 103.03 23.37 490.00 314705.9 225850.4 101.77 5.21 101.87 6.44 101.96 7.74 102.01 9.66 102.09 11.45 102.17 13.53 102.25 15.96 102.56 23.37 522.00 314722.7 225873.1 101.29 5.21 101.50 6.50 101.61 7.86 101.56 9.66 101.65 11.45 101.75 13.53 101.86 15.96 102.33 23.37 532.28 314720.9 225883.3 101.23 5.21 101.51 6.55 101.73 8.00 101.50 9.66 101.59 11.45 101.69 13.54 101.80 15.96 102.29 23.37 542.63 314718.6 225893.3 101.13 7.81 101.37 9.80 101.51 11.80 101.38 14.50 101.47 17.17 101.57 20.30 101.68 23.94 101.94 35.06 590.00 314707.1 225938.5 100.58 10.28 101.02 12.54 101.20 14.19 100.58 14.92 100.62 16.84 100.65 19.08 100.73 21.73 100.81 29.38 640.70 314706.8 225988.0 100.59 10.15 101.03 12.05 101.21 12.86 100.67 10.51 100.74 10.80 100.81 11.09 100.92 11.55 101.02 12.01 660.63 314702.5 226007.2 98.53 10.15 98.63 12.02 98.68 12.85 98.55 10.51 98.57 10.80 98.58 11.09 98.63 11.59 98.67 12.08 690.00 314688.1 226031.6 97.93 10.15 98.02 12.29 98.10 13.94 97.95 10.70 97.97 11.06 97.99 11.44 98.07 12.92 98.15 14.25 750.00 314647.9 226073.5 96.56 10.15 96.65 12.57 96.74 15.03 96.59 10.90 96.61 11.32 96.62 11.77 96.71 14.21 96.85 16.36 801.00 314634.2 226121.0 95.33 10.15 95.46 12.57 95.53 15.03 95.36 10.90 95.36 11.32 95.41 11.77 95.51 14.21 95.94 16.40 820.00 314621.8 226135.4 94.75 10.15 94.97 12.56 95.04 15.03 94.81 10.90 94.79 11.32 94.90 11.77 95.06 14.21 95.68 16.53 900.00 314635.7 226204.9 93.54 10.15 94.05 12.56 94.15 15.35 93.72 10.99 93.64 11.38 93.91 12.08 94.24 15.03 94.31 17.24 935.00 314627.4 226238.3 91.60 10.15 91.74 12.54 91.91 15.77 91.95 14.27 92.00 15.48 92.05 16.85 91.98 17.15 92.02 18.68 950.69 314625.9 226253.9 90.13 10.14 90.23 12.54 90.38 16.06 90.48 18.03 90.59 20.52 90.70 22.84 90.65 20.29 90.79 22.15 1010.09 314584.4 226288.5 88.63 10.14 88.75 12.56 88.91 16.30 89.03 18.96 89.16 22.20 89.29 25.70 89.37 25.73 89.64 32.80 1014.13 314582.3 226292.0 88.56 10.14 88.67 12.56 88.84 16.40 88.95 19.31 89.08 22.88 89.22 27.03 89.30 29.46 89.56 41.09 1090.00 314585.4 226360.8 87.05 10.14 87.16 12.56 87.30 16.27 87.42 19.31 87.54 22.88 87.65 27.03 87.75 29.95 87.95 40.16 1150.00 314615.6 226411.7 86.03 10.14 86.13 12.56 86.25 15.81 86.38 19.28 86.48 22.77 86.58 26.59 86.70 30.62 86.82 37.31 1180.56 314613.5 226442.0 85.45 10.14 85.56 12.56 85.67 15.50 85.82 19.25 85.91 22.65 86.00 26.15 86.13 30.91 86.25 35.68 1183.20 314613.1 226444.6 85.27 10.14 85.37 12.56 85.48 15.47 85.61 19.25 85.72 22.65 85.82 26.15 85.96 30.91 86.09 35.68 1185.84 314612.7 226447.2 85.14 10.14 85.25 12.56 85.37 15.52 85.51 19.25 85.62 22.65 85.73 26.15 85.87 30.91 85.99 35.68 1220.00 314603.1 226479.9 84.62 10.14 84.73 12.56 84.84 15.63 84.95 19.25 85.04 22.65 85.12 26.15 85.24 30.91 85.35 35.68 1280.00 314573.9 226532.1 83.77 10.14 83.87 12.55 83.99 15.47 83.97 17.02 83.99 18.92 83.99 20.77 84.05 23.86 84.16 27.47 1324.80 314586.9 226572.7 83.18 10.14 83.32 12.54 83.47 15.24 83.45 14.78 83.47 15.18 83.48 15.39 83.56 16.81 83.70 19.26 1326.00 314587.9 226573.4 83.18 10.14 83.33 12.54 83.48 15.24 83.46 14.78 83.48 15.18 83.49 15.39 83.57 16.81 83.72 19.25 1332.53 314593.4 226577.0 82.61 10.14 82.68 12.54 82.76 15.24 82.74 14.78 82.76 15.18 82.77 15.39 82.81 16.84 82.88 19.30 1370.00 314600.2 226610.9 80.77 10.14 80.86 12.54 80.96 15.24 80.97 15.08 81.03 16.16 81.09 17.17 81.12 18.42 81.28 22.10 1430.00 314567.3 226660.3 80.26 10.14 80.38 12.54 80.50 15.24 80.50 15.38 80.57 17.13 80.63 18.95 80.67 19.98 80.85 25.15 1480.00 314538.7 226700.9 79.57 10.14 79.66 12.52 79.75 15.15 79.72 14.94 79.76 16.36 79.79 17.81 79.81 18.72 79.89 22.83


50% AEP 20% AEP 10% AEP 4% AEP 2% AEP 1% AEP 0.5% AEP 0.1% AEP


(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Whitechurch Stream_Present Day (cont'd)

1550.00 314564.8 226764.5 78.51 10.13 78.59 12.30 78.66 14.53 78.60 13.43 78.61 14.08 78.62 14.75 78.65 15.65 78.68 17.41 1647.00 314594.4 226850.6 77.77 10.13 77.82 12.10 77.86 13.99 77.82 12.36 77.83 12.56 77.84 12.83 77.87 13.91 77.90 14.87 1664.00 314601.8 226865.9 76.59 10.13 76.69 12.10 76.78 13.99 76.70 12.36 76.71 12.56 76.73 12.84 76.78 14.00 76.88 15.16 1714.14 314608.8 226915.1 75.74 10.13 75.85 12.10 75.95 13.99 75.87 12.36 75.88 12.56 75.89 12.84 75.95 14.00 76.02 15.16 1716.00 314609.8 226916.7 75.72 10.13 75.82 12.10 75.92 13.99 75.84 12.36 75.85 12.56 75.87 12.84 75.93 14.00 75.99 15.16 1718.94 314611.4 226919.2 75.67 10.13 75.78 12.10 75.88 13.99 75.79 12.36 75.80 12.56 75.82 12.84 75.88 14.00 75.94 15.16 1777.18 314600.8 226968.5 74.24 10.13 74.34 12.10 74.48 14.54 74.38 12.61 74.40 12.94 74.43 13.37 74.50 14.04 74.60 15.21 1830.00 314564.0 227005.3 73.65 10.13 73.72 12.10 73.82 15.14 73.75 12.93 73.77 13.49 73.80 14.17 74.00 17.13 74.16 19.91 1870.46 314531.4 227028.3 73.12 10.13 73.21 12.10 73.35 15.19 73.25 13.00 73.28 13.66 73.32 14.44 73.62 20.75 73.84 25.63 1880.00 314527.3 227036.9 72.61 10.13 72.71 12.10 72.85 15.19 72.75 13.00 72.78 13.66 72.83 14.44 73.16 21.32 73.41 26.69 1906.00 314522.7 227062.2 72.53 10.13 72.62 12.10 72.76 15.19 72.66 13.00 72.69 13.66 72.73 14.44 73.02 21.35 73.21 26.73 1919.50 314524.3 227075.6 72.42 10.13 72.51 12.10 72.66 15.19 72.54 13.15 72.58 13.92 72.62 14.79 72.93 21.46 73.13 26.73 1922.00 314524.7 227078.1 72.40 10.13 72.49 12.10 72.64 15.19 72.52 13.30 72.56 14.17 72.60 15.14 72.91 21.56 73.11 26.69 1924.34 314525.1 227080.4 72.37 10.13 72.45 12.10 72.57 15.18 72.48 13.25 72.51 14.11 72.54 15.08 72.76 21.56 72.87 26.69 1950.00 314525.1 227105.1 72.20 10.13 72.27 12.10 72.38 15.18 72.29 12.80 72.32 13.60 72.34 14.50 72.56 21.55 72.65 26.70 2014.48 314486.3 227150.2 71.90 7.67 71.93 8.97 71.96 11.00 71.91 8.91 71.91 9.36 71.92 9.87 72.06 14.71 72.06 17.50 2019.02 314486.8 227154.7 71.93 4.75 71.96 5.24 72.02 5.99 71.94 4.91 71.95 5.02 71.96 5.17 72.13 7.10 72.15 7.44 2021.88 314486.6 227157.6 68.40 4.28 68.46 4.63 68.56 5.16 68.35 4.40 68.37 4.49 68.39 4.59 68.64 6.35 68.80 6.61 2077.06 314455.9 227187.0 68.21 4.70 68.28 5.40 68.39 6.55 68.14 4.53 68.16 4.66 68.18 4.86 68.47 8.11 68.64 9.52 2078.46 314454.6 227186.5 68.20 5.55 68.27 6.68 68.38 8.57 68.13 4.74 68.14 4.95 68.17 5.27 68.45 8.98 68.62 11.12 2150.00 314455.4 227241.0 67.64 8.01 67.73 9.61 67.87 12.16 67.52 6.30 67.58 6.89 67.63 7.60 68.13 15.01 68.31 19.30 2245.13 314429.2 227317.9 66.59 10.08 66.68 12.06 66.81 15.14 66.52 8.18 66.57 9.21 66.63 10.38 67.01 20.98 67.04 24.70 2246.63 314427.8 227318.5 66.57 10.11 66.66 12.09 66.79 15.17 66.50 8.60 66.55 9.71 66.61 10.97 66.99 20.02 67.02 20.62 2326.41 314410.1 227395.0 65.40 10.11 65.50 12.09 65.63 15.17 65.33 8.60 65.39 9.71 65.45 10.97 65.85 20.02 65.92 20.62 2328.00 314409.7 227396.5 65.34 10.11 65.43 12.09 65.55 15.17 65.27 8.60 65.32 9.71 65.38 10.97 65.76 20.02 65.84 20.61 2330.57 314408.9 227399.0 65.27 10.11 65.36 12.09 65.47 15.17 65.21 8.60 65.26 9.71 65.31 10.97 65.68 20.02 65.76 20.62 2400.00 314405.4 227466.9 64.57 10.11 64.65 12.09 64.77 15.17 64.51 8.64 64.57 9.76 64.62 11.04 65.10 22.79 65.30 26.85 2472.19 314433.9 227529.5 63.01 10.11 63.14 12.09 63.35 15.17 63.00 8.69 63.11 9.82 63.20 11.10 63.80 25.55 64.03 33.09 2475.00 314432.3 227531.8 62.98 10.11 63.10 12.09 63.32 15.17 62.98 8.69 63.08 9.82 63.18 11.10 63.78 25.55 64.00 33.09 2479.34 314429.5 227535.0 62.92 10.11 63.05 12.09 63.27 15.17 62.93 8.69 63.04 9.82 63.14 11.10 63.72 25.54 63.95 33.09 2523.28 314390.9 227554.7 62.45 10.11 62.58 12.09 62.76 15.17 62.67 8.72 62.80 9.86 62.90 11.15 63.23 25.54 63.41 33.09 2550.00 314364.8 227553.2 62.26 10.11 62.40 12.09 62.60 15.17 62.57 11.46 62.70 12.94 62.78 14.51 63.04 27.19 63.18 34.00 2580.00 314354.8 227578.0 62.13 10.11 62.27 12.09 62.48 15.17 62.46 14.54 62.58 16.51 62.66 18.12 62.84 25.15 62.94 29.10 2589.08 314353.2 227586.9 61.17 10.11 61.32 12.09 61.53 15.17 61.51 14.93 61.63 17.04 61.70 18.40 61.88 21.48 62.00 23.30 2593.00 314350.3 227589.5 60.92 10.11 61.05 12.09 61.25 15.17 61.22 14.93 61.32 17.04 61.38 18.40 61.55 21.48 61.65 23.30 2598.32 314346.1 227592.7 60.77 10.11 60.90 12.09 61.09 15.17 61.05 14.94 61.15 17.05 61.20 18.43 61.35 21.51 61.43 23.33 2650.00 314344.3 227644.0 60.05 10.11 60.18 12.09 60.36 15.16 60.28 14.33 60.32 15.74 60.37 16.88 60.61 20.23 60.70 21.87 2702.44 314344.0 227694.9 59.45 10.11 59.60 12.09 59.83 15.16 59.73 13.71 59.78 14.41 59.84 15.30 60.15 18.92 60.28 20.36 2726.20 314339.0 227718.1 58.91 10.11 59.08 12.09 59.34 15.16 59.22 13.71 59.27 14.41 59.35 15.30 59.64 18.92 59.81 20.36 2760.00 314333.5 227751.5 58.77 10.11 58.95 12.09 59.22 15.16 59.09 13.71 59.15 14.41 59.23 15.30 59.53 18.92 59.71 20.36 2818.73 314329.8 227810.0 58.06 10.11 58.26 12.09 58.57 15.15 58.43 13.71 58.50 14.41 58.59 15.30 58.93 18.92 59.19 20.36 2869.97 314311.9 227857.5 57.19 10.11 57.32 12.09 57.52 15.15 57.43 13.71 57.47 14.41 57.53 15.30 57.74 18.92 57.82 20.36 2909.30 314300.1 227895.1 57.03 10.11 57.18 12.09 57.38 15.15 57.29 13.71 57.33 14.41 57.39 15.30 57.61 18.92 57.70 20.36 2919.62 314297.6 227905.0 56.56 10.11 56.66 12.09 56.80 15.15 56.74 13.71 56.77 14.41 56.81 15.30 57.01 18.92 57.12 20.36


50% AEP 20% AEP 10% AEP 4% AEP 2% AEP 1% AEP 0.5% AEP 0.1% AEP


(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s)

Whitechurch Stream_Present Day (cont'd)

2972.67 314298.2 227954.3 56.11 10.11 56.20 12.09 56.34 15.15 56.28 13.71 56.31 14.41 56.35 15.30 56.59 18.92 56.74 20.36

2974.00 314297.8 227955.6 56.08 10.11 56.17 12.09 56.31 15.15 56.25 13.71 56.28 14.41 56.32 15.30 56.56 18.92 56.71 20.36

2976.36 314297.3 227957.9 56.06 10.11 56.15 12.09 56.28 15.15 56.22 13.71 56.25 14.41 56.29 15.30 56.49 18.92 56.63 20.36

2990.00 314295.7 227971.5 55.74 10.11 55.83 12.09 55.97 15.15 55.91 13.71 55.94 14.41 55.98 15.30 56.24 18.92 56.43 20.36

3033.22 314276.4 228009.9 54.49 10.11 54.61 12.09 54.82 15.15 54.73 13.71 54.77 14.41 54.83 15.30 55.49 18.92 55.88 20.36

3040.21 314272.2 228015.5 54.27 10.11 54.46 12.09 54.72 15.15 54.61 13.71 54.67 14.41 54.74 15.30 55.58 18.92 55.97 20.36

3043.81 314270.0 228018.4 54.26 10.11 54.45 12.09 54.72 15.15 54.60 13.71 54.66 14.41 54.73 15.30 55.58 18.92 55.96 20.36

3153.17 314264.0 228125.4 52.54 10.11 52.67 12.09 52.86 15.15 52.77 13.71 52.81 14.41 52.87 15.30 53.06 18.91 53.14 20.35

3201.89 314259.8 228173.3 51.68 10.11 51.82 12.09 52.01 15.15 51.92 13.71 51.97 14.41 52.02 15.30 52.21 18.91 52.30 20.35

3203.00 314259.7 228174.4 51.66 10.11 51.79 12.09 51.99 15.15 51.90 13.71 51.94 14.41 51.99 15.30 52.18 18.91 52.27 20.35

3204.34 314259.3 228175.7 51.65 10.11 51.77 12.09 51.94 15.15 51.86 13.71 51.90 14.41 51.95 15.30 52.14 18.91 52.21 20.35

3230.00 314251.3 228199.6 51.26 10.11 51.36 12.09 51.49 15.15 51.43 13.71 51.46 14.41 51.50 15.30 51.65 18.91 51.71 20.35

3260.00 314239.4 228227.0 50.85 10.11 50.95 12.09 51.09 15.15 51.02 13.71 51.05 14.41 51.09 15.30 51.25 18.86 51.31 20.34

3305.58 314234.0 228272.0 50.31 10.11 50.42 12.09 50.59 15.15 50.50 13.71 50.54 14.41 50.58 15.30 50.76 18.80 50.85 20.33

3314.50 314235.6 228280.7 49.95 10.11 50.04 12.09 50.17 15.15 50.09 13.71 50.12 14.41 50.15 15.30 50.30 18.80 50.38 20.33

3323.30 314237.2 228289.4 49.88 10.11 49.97 12.09 50.09 15.16 50.01 13.71 50.03 14.41 50.06 15.30 50.21 18.80 50.29 20.33

3338.62 314235.1 228304.4 49.24 10.11 49.25 12.09 49.25 15.45 49.14 13.72 49.13 14.41 49.12 15.30 49.19 18.80 49.27 20.33

3353.00 314231.6 228318.3 48.04 11.08 48.10 12.09 48.26 15.73 48.28 13.98 48.38 14.41 48.70 15.30 48.65 18.80 48.91 20.33

3354.00 314231.3 228319.3 47.91 12.04 48.07 12.09 48.23 15.73 48.28 14.23 48.38 14.41 48.48 15.30 48.65 18.80 48.91 20.33


Water Surface Profiles Whitechurch Stream - Present Day Scenario

45.00

55.00

65.00

75.00

85.00

95.00

105.00

115.00

0.00 500.00 1000.00 1500.00 2000.00 2500.00 3000.00 3500.00

Chainage

Ma

x H

50% AEP Max H

20% AEP Max H

10% AEP Max H

4% AEP Max H

2% AEP Max H

1% AEP Max H

0.5% AEP Max H

0.1% AEP Max H


Little Dargle Stream 50% AEP 20% AEP 10% AEP 4% AEP 2% AEP 1% AEP 0.5% AEP 0.1% AEP


Little Dargle Stream – Present Day 0.00 315460.8 226044.7 88.78 5.93 88.80 7.33 88.82 8.89 88.85 11.18 88.89 13.16 88.93 15.39 88.97 18.36 89.03 26.32

110.00 315485.8 226129.6 88.24 5.82 88.32 7.21 88.41 8.76 88.53 11.04 88.62 13.01 88.73 15.23 88.84 17.98 89.13 25.57 120.00 315486.7 226137.7 85.64 5.71 85.65 7.09 85.65 8.63 85.65 10.90 85.65 12.86 85.66 15.08 85.66 17.60 88.19 24.81 200.00 315499.3 226200.8 85.54 5.70 85.62 7.08 85.71 8.62 85.83 10.89 85.92 12.85 86.03 15.07 86.14 17.59 87.75 24.81 220.00 315502.6 226216.6 83.23 5.70 83.26 7.08 83.28 8.62 83.32 10.89 84.96 12.85 85.32 15.06 85.82 17.57 87.74 24.81 360.00 315526.1 226327.1 83.54 5.70 83.76 7.08 83.80 8.62 84.35 10.89 84.78 12.85 85.36 15.08 85.83 17.59 87.75 24.80 380.00 315529.4 226342.9 83.36 5.69 83.73 7.08 83.79 8.66 84.33 10.90 84.76 12.88 85.35 15.09 85.82 17.61 87.74 24.82 417.00 315535.7 226372.1 82.74 5.68 83.66 7.09 83.73 8.80 84.34 10.93 84.69 13.00 85.31 15.09 85.82 17.59 87.75 24.68 657.53 315619.8 226586.0 82.64 5.67 83.06 6.15 83.46 7.40 84.04 8.68 84.58 10.15 85.18 11.20 85.79 13.05 87.56 17.75 709.36 315633.9 226635.8 83.19 5.32 83.18 5.03 83.49 5.59 84.04 5.98 84.59 6.49 85.19 6.66 85.79 7.38 87.57 8.94 977.17 315793.8 226846.0 76.83 5.33 76.88 5.66 76.93 6.26 76.98 6.81 77.01 7.24 77.05 7.72 77.09 8.22 77.21 9.61 1149.08 315857.3 226999.0 74.78 5.72 74.84 6.52 74.90 7.30 74.96 8.14 75.00 8.80 75.06 9.51 75.12 10.31 75.29 12.51 1240.00 315896.5 227080.4 73.73 5.80 73.80 6.60 73.86 7.40 73.93 8.27 73.99 8.95 74.08 9.68 74.20 10.50 74.48 12.75 1300.00 315921.8 227131.7 72.95 5.86 73.06 6.67 73.16 7.49 73.27 8.38 73.38 9.07 73.58 9.81 73.85 10.63 74.44 12.87 1400.00 315919.2 227229.2 72.37 5.91 72.43 6.75 72.48 7.57 72.54 8.48 72.58 9.18 72.64 9.94 72.68 10.76 72.80 12.97 1454.61 315932.9 227276.9 71.82 5.97 71.87 6.82 71.91 7.65 71.96 8.58 72.01 9.29 72.09 10.07 72.13 10.89 72.25 13.15 1570.00 315829.0 227285.3 71.02 6.04 71.09 6.90 71.15 7.76 71.23 8.70 71.29 9.43 71.48 10.22 71.52 11.07 71.81 13.33 1670.00 315752.9 227350.1 69.89 6.12 69.97 7.00 70.04 7.87 70.15 8.83 70.24 9.59 70.33 10.39 70.42 11.25 71.51 13.48 1770.00 315667.1 227400.6 68.92 6.18 68.98 7.08 69.05 7.97 69.12 8.95 69.17 9.72 69.23 10.54 69.29 11.42 69.46 13.63 1828.00 315613.0 227418.2 67.94 6.24 68.02 7.16 68.09 8.05 68.19 9.05 68.26 9.83 68.35 10.66 68.44 11.56 68.72 13.79 1921.99 315554.2 227490.2 67.57 6.29 67.72 7.22 67.86 8.12 68.01 9.13 68.12 9.93 68.24 10.76 68.37 11.68 68.68 13.92 1946.99 315535.8 227507.2 66.16 6.32 66.20 7.26 66.23 8.17 66.26 9.20 66.28 10.00 66.31 10.84 66.33 11.77 66.39 14.02 1996.69 315498.6 227540.1 63.78 6.36 63.83 7.31 63.89 8.23 63.95 9.26 63.99 10.07 64.03 10.92 64.08 11.86 64.18 14.12 2070.00 315436.8 227578.3 62.94 6.41 62.98 7.37 63.02 8.30 63.06 9.35 63.09 10.18 63.12 11.03 63.15 11.99 63.23 14.26 2153.88 315374.2 227632.8 59.08 6.46 59.27 7.44 59.45 8.38 59.65 9.45 59.81 10.29 59.95 11.14 60.13 12.12 60.51 14.41 2220.00 315353.4 227695.1 59.05 6.51 59.25 7.50 59.44 8.45 59.64 9.53 59.79 10.38 59.94 11.23 60.12 12.24 60.50 14.53 2280.00 315342.5 227753.6 57.70 6.56 57.76 7.57 57.82 8.52 57.88 9.62 57.92 10.48 57.97 11.34 58.02 12.37 58.12 14.67 2384.85 315329.9 227857.6 55.87 6.62 55.92 7.65 55.96 8.62 56.01 9.74 56.04 10.62 56.08 11.48 56.12 12.54 56.20 14.86 2468.21 315339.1 227938.6 54.79 6.69 54.83 7.73 54.87 8.71 54.90 9.85 54.92 10.75 54.95 11.62 54.98 12.71 55.03 15.04 2565.29 315366.9 228031.3 54.36 6.76 54.10 7.82 54.22 8.81 54.39 10.00 54.19 10.89 54.22 11.77 54.39 12.91 54.31 15.23 2665.51 315358.8 228130.7 52.86 6.81 52.60 7.89 52.76 8.89 52.96 10.09 52.78 11.00 52.82 11.90 52.95 13.05 52.98 15.39 2670.00 315359.6 228135.2 52.80 6.84 52.54 7.91 52.69 8.93 52.89 10.11 52.71 11.04 52.76 11.96 52.88 13.07 52.92 15.45 2680.00 315360.2 228145.7 52.49 6.87 52.26 7.96 52.41 8.97 52.59 10.17 52.42 11.11 52.46 12.05 52.59 13.17 52.62 15.56 2860.00 315384.5 228322.7 51.17 6.94 50.99 8.05 51.10 9.08 51.26 10.29 51.15 11.27 51.19 12.23 51.26 13.36 51.33 15.77 2900.00 315388.3 228362.7 50.86 6.99 50.69 8.12 50.80 9.16 50.94 10.38 50.84 11.36 50.88 12.35 50.94 13.48 51.01 15.92 2910.00 315389.3 228372.8 50.50 7.04 50.37 8.18 50.45 9.24 50.57 10.49 50.49 11.48 50.52 12.49 50.58 13.62 50.64 16.15 3150.00 315389.8 228602.6 46.68 7.12 46.60 8.30 46.65 9.37 46.78 10.66 46.74 11.66 46.79 12.71 46.86 13.86 47.14 16.66 3160.00 315392.3 228612.3 46.15 7.25 45.96 8.49 46.10 9.60 46.43 10.93 46.32 11.97 46.44 13.07 46.57 14.24 47.01 17.64 3712.00 315506.2 229137.9 37.63 7.47 37.54 8.75 37.62 9.90 37.78 11.30 37.78 12.39 37.85 13.63 37.92 14.99 38.24 18.99 3717.00 315506.2 229137.9 37.60 7.60 37.51 8.91 37.60 10.09 37.75 11.52 37.75 12.65 37.81 14.02 37.88 15.54 38.22 19.78 3810.00 315528.2 229224.3 36.24 7.68 36.19 8.97 36.24 10.17 36.34 11.60 36.38 12.79 36.45 14.20 36.55 15.76 37.59 19.96 3880.00 315558.2 229281.5 35.34 7.74 35.30 9.06 35.37 10.25 35.48 11.73 35.61 13.01 35.76 14.45 36.06 16.02 37.59 19.79 4020.00 315498.1 229381.6 33.46 7.86 33.70 9.14 33.91 10.34 34.33 11.81 34.82 13.05 35.38 14.40 36.00 15.85 37.60 19.22 4107.00 315421.7 229413.0 33.43 7.93 33.67 9.19 33.88 10.39 34.30 11.84 34.80 13.00 35.37 14.24 35.99 15.59 37.59 18.94 4235.00 315430.7 229533.4 29.66 7.93 30.03 9.21 30.24 10.41 30.50 11.86 30.74 13.00 30.91 14.27 31.10 15.63 31.10 19.00


Water Surface ProfileLittle Dargle Stream - Present Day Scenario

0

10

20

30

40

50

60

70

80

90

100

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Chainage (m)

Max

H

50% AEP Max H

20% AEP Max H

10% AEP Max H

4% AEP Max H

2% AEP Max H

1% AEP Max H

0.5% AEP Max H

0.1% AEP Max H


Dundrum Slang Stream

50% AEP 20%


AEP 0.1% AEP


(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Dundrum Slang_Present Day

0 316439.78 227187.6 69.131 0.102 69.151 0.103 69.171 0.104 69.208 0.105 69.245 0.107 69.292 0.112 69.361 0.511 70.327 0.314 3.53 316443.31 227187.6 69.106 0.216 69.123 0.264 69.141 0.314 69.172 0.404 69.204 0.498 69.246 0.621 69.308 0.782 70.325 1.318 210 316645.34 227195.8 68.354 0.413 68.419 0.542 68.484 0.676 68.597 0.919 68.703 1.17 68.839 1.499 69.012 1.931 70.321 3.313 370 316795.06 227139.6 68.191 0.574 68.268 0.77 68.343 0.973 68.469 1.341 68.583 1.721 68.729 2.22 68.913 2.874 70.316 4.912

510.39 316910 227186.1 67.949 0.657 68.036 0.887 68.119 1.126 68.258 1.558 68.403 2.005 68.579 2.591 68.785 3.361 70.314 5.407 524.9 316920.38 227196.2 67.821 0.726 67.903 0.985 67.98 1.254 68.101 1.74 68.209 2.242 68.338 2.902 68.491 3.769 69.987 6.16 640 317007.81 227270 67.645 0.827 67.729 1.128 67.805 1.441 67.926 2.006 68.04 2.587 68.174 3.357 68.326 4.366 69.986 7.191

714.85 317077.03 227297 67.556 0.872 67.627 1.192 67.694 1.524 67.805 2.125 67.918 2.741 68.048 3.561 68.192 4.634 69.983 7.635 725 317086.5 227300.7 67.525 0.883 67.593 1.208 67.658 1.544 67.765 2.153 67.877 2.778 68.002 3.609 68.133 4.697 69.879 7.745 735 317095.81 227304.3 67.51 1.033 67.578 1.379 67.643 1.737 67.752 2.385 67.867 3.048 67.992 3.936 68.122 5.095 69.88 8.273 735 317095.81 227304.3 67.51 1.126 67.578 1.511 67.643 1.909 67.752 2.631 67.867 3.365 67.992 4.357 68.122 5.648 69.88 9.172 820 317178.78 227315.1 67.249 1.192 67.325 1.604 67.399 2.031 67.525 2.804 67.668 3.588 67.803 4.653 67.92 6.037 69.882 9.741

911.36 317264.84 227326.1 67.035 1.27 67.135 1.715 67.225 2.176 67.371 3.01 67.542 3.855 67.691 5.007 67.807 6.501 69.879 10.382 944.31 317296.81 227318.4 66.979 1.41 67.073 1.914 67.157 2.435 67.293 3.38 67.462 4.333 67.616 5.639 67.734 7.328 69.878 12.745 1060 317396.13 227275 66.591 1.516 66.68 2.063 66.758 2.63 66.884 3.658 66.993 4.692 67.124 6.108 67.267 7.882 69.879 35.245 1210 317523.81 227335.8 65.87 1.573 65.946 2.144 66.017 2.736 66.13 3.809 66.225 4.888 66.35 6.359 66.698 8.128 69.881 29.031 1260 317556.63 227373.5 65.495 1.62 65.57 2.212 65.642 2.824 65.761 3.935 65.87 5.051 66.014 6.542 66.602 8.265 69.876 36.927

1318.82 317586.47 227423 64.838 1.657 64.929 2.264 65.02 2.893 65.17 4.034 65.302 5.177 65.625 6.669 66.585 8.215 69.882 26.918 1350 317591.94 227453.7 64.67 1.694 64.743 3.137 64.822 2.961 64.961 7.35 65.09 9.617 65.566 8.628 66.587 9.288 69.9 27.63 1388 317580.44 227487.3 64.193 1.729 64.347 2.368 64.503 3.028 64.726 4.244 64.946 5.468 65.576 6.898 66.579 22.449 69.977 66.664

1416.2 317592.09 227505.6 64.174 4.634 64.333 6.362 64.483 8.07 64.72 11.026 64.938 13.901 65.493 17.521 66.537 22.179 69.957 66.339 1450 317613.16 227528.3 64.105 4.671 64.284 6.413 64.446 8.136 64.693 11.121 64.918 14.027 65.485 17.571 66.777 21.327 70.429 177.981 1510 317614.47 227582.8 63.387 4.679 63.548 6.424 63.686 8.151 63.885 11.142 64.081 14.054 65.1 17.608 66.446 21.353 70.201 165.156

1517.46 317608.94 227587.7 63.345 4.687 63.51 6.436 63.649 8.167 63.849 11.164 64.048 14.083 65.094 17.619 66.423 21.249 70.069 122.381 1524.93 317605.13 227593.9 63.272 4.709 63.432 6.467 63.567 8.208 63.75 11.222 63.936 14.16 64.963 17.661 66.475 21.044 70.15 34.245 1533.1 317598.16 227597.7 63.188 4.788 63.355 6.57 63.494 8.331 63.676 11.341 63.865 13.96 64.959 16.762 66.468 19.966 70.413 35.745 1565.95 317569 227612.9 62.652 5.389 62.754 7.427 62.897 9.452 63.2 12.908 63.793 15.621 64.814 18.772 66.084 22.486 69.05 26.553 1688.14 317491.66 227683.2 62.247 5.766 62.486 7.961 62.701 10.15 63.062 13.899 63.707 16.85 64.762 20.284 66.051 24.266 69.032 72.519 2555.68 316944.16 228111.2 43.761 5.803 43.922 8.013 44.068 10.219 44.293 13.996 44.444 16.971 44.614 20.433 44.912 24.435 46.261 70.566 2581.85 316933.25 228134.7 43.513 5.839 43.695 8.064 43.86 10.284 44.103 14.089 44.258 17.087 44.438 20.577 44.807 24.591 46.314 54.747 2626.71 316920.09 228176.9 43.105 5.916 43.32 8.173 43.524 10.426 43.832 14.291 44.049 17.337 44.292 20.885 44.779 24.948 46.499 32.44

2650 316923.06 228199.1 43.045 6.01 43.253 8.306 43.439 10.599 43.732 14.537 43.942 17.644 44.182 21.264 44.687 25.393 46.493 32.24 2773.91 316962.84 228316.5 42.572 6.057 42.745 8.373 42.933 10.687 43.203 14.661 43.42 17.799 43.63 21.456 43.907 25.617 44.42 32.573

2830 316973.59 228371.2 42.201 6.093 42.38 8.424 42.581 10.753 42.845 14.755 43.068 17.916 43.268 21.602 43.516 25.789 44.07 32.886 2864.44 316981.41 228404.5 41.994 6.126 42.162 8.469 42.38 10.812 42.64 14.839 42.874 18.021 43.069 21.732 43.323 25.943 43.917 33.207 2898.87 316989.63 228436.5 41.439 6.146 41.629 8.499 41.947 10.849 42.189 14.893 42.445 18.088 42.612 21.815 42.781 26.042 43.077 33.403 2925.9 316973.41 228458.2 41.066 6.159 41.301 8.517 41.746 10.873 41.967 14.926 42.241 18.13 42.387 21.867 42.531 26.104 42.798 33.52 2938.15 316968.03 228469.1 41.023 6.186 41.262 8.555 41.701 10.922 41.938 14.997 42.212 18.219 42.351 21.98 42.488 26.207 42.744 33.639 2950.4 316963 228480.3 40.979 6.225 41.223 8.61 41.675 10.941 41.903 12.864 42.163 13.816 42.28 15.044 42.389 16.658 42.585 18.937 2990 316945.94 228515.9 40.807 6.248 41.069 8.642 41.581 10.982 41.783 11.564 42.04 12.879 42.125 14.389 42.197 16.089 42.339 18.195

3024.28 316941.16 228549.9 40.499 6.292 40.769 8.705 41.399 11.064 41.603 11.682 41.923 13.003 41.973 14.571 42.031 16.306 42.16 18.549 3034.14 316939.84 228559.6 40.451 6.367 40.717 8.811 41.366 11.202 41.577 11.882 41.902 14.645 41.952 16.573 42.007 17.005 42.133 18.14

3110 316929.5 228634.7 40.068 6.405 40.269 8.865 40.442 11.273 40.505 11.984 40.791 17.187 40.934 18.93 41.062 19.852 41.495 39.048 3178 316925.03 228702.2 39.608 6.411 39.837 8.874 40.032 11.285 40.133 12.001 40.516 17.203 40.687 18.972 40.905 19.781 41.544 21.422


50% AEP 20%


AEP 0.1% AEP


(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Dundrum Slang_Present Day

3184 316925.31 228708.2 39.572 6.434 39.804 8.906 40.003 11.326 40.109 12.061 40.491 17.409 40.668 19.377 40.884 20.299 41.51 22.714 3190.28 316925.03 228714.5 39.547 6.456 39.78 8.937 39.979 11.367 40.087 14.296 40.433 19.088 40.598 23.068 40.81 27.582 41.505 35.004

3227 316923.16 228751.2 39.35 6.462 39.575 8.946 39.753 11.379 39.901 14.31 40.172 19.109 40.372 23.079 40.639 27.568 41.221 36.381 3233.27 316922.84 228757.4 39.318 6.486 39.543 8.981 39.727 11.424 39.881 14.363 40.153 19.188 40.352 23.176 40.62 27.655 41.23 35.976 3239.54 316921.97 228763.6 39.321 6.516 39.549 9.025 39.724 11.481 39.865 14.431 40.135 19.289 40.333 23.302 40.577 27.779 41.163 36.434

3280 316919 228803.8 39.14 6.541 39.387 9.061 39.569 11.529 39.7 14.488 40.046 19.372 40.268 23.406 40.551 27.903 41.222 36.582 3300 316912.63 228822.8 39.063 6.562 39.33 9.092 39.505 11.569 39.631 14.551 40.018 19.443 40.254 23.494 40.543 27.997 41.219 36.655 3330 316908.34 228852.4 39 6.576 39.254 9.111 39.406 11.594 39.507 14.596 39.926 19.486 40.176 23.548 40.489 28.06 41.202 36.788 3342 316907.34 228864.3 38.921 6.59 39.162 9.131 39.313 11.621 39.437 14.703 39.803 19.533 40.038 23.606 40.329 28.128 41.012 36.922 3356 316905.09 228878.1 38.9 6.637 39.144 9.2 39.292 11.711 39.343 12.668 39.783 19.69 40.019 23.801 40.313 28.351 41.001 37.381 3370 316901.53 228891.7 38.846 6.766 39.087 9.125 39.223 10.936 39.095 8.444 39.562 15.16 39.684 16.941 39.808 18.54 40.01 21.669 3450 316883.59 228969.4 38.626 6.904 38.865 8.374 38.995 9.932 37.431 8.506 39.322 11.105 39.432 11.397 39.542 11.891 39.719 13.484 3620 316897.22 229138 37.325 6.965 37.427 8.466 37.532 10.51 36.783 8.57 37.656 19.049 37.672 21.851 37.722 24.151 38.093 28.694 3720 316925.34 229234 36.7 6.998 36.78 8.518 36.88 10.555 36.629 8.647 37.246 19.154 37.406 21.991 37.62 24.486 38.187 27.154

3738.29 316930.91 229251.4 36.559 7.027 36.627 8.562 36.712 10.594 35.123 8.672 37.043 20.631 37.216 24.841 37.466 28.89 38.09 34.589 3785 316949.22 229293.9 35.024 7.036 35.117 8.576 35.238 10.606 34.988 8.718 35.752 20.66 36.252 24.883 36.851 28.932 37.849 34.624

3794.11 316954.66 229301.2 34.893 7.055 34.982 8.604 35.101 10.631 34.644 9.172 35.625 20.716 36.204 24.954 36.831 29.018 37.846 37.083 3803.22 316960.13 229308.5 34.556 7.114 34.638 8.692 34.754 10.711 33.696 9.28 35.276 20.899 35.5 25.189 35.7 29.77 35.844 42.11

3830 316973.03 229331.9 33.581 7.206 33.67 8.817 33.772 10.833 33.14 9.655 34.235 21.183 34.415 25.554 34.539 30.21 34.845 44.247 3920 316986.88 229420.2 33.01 7.27 33.111 8.917 33.22 10.916 32.093 9.681 33.643 21.381 33.796 25.808 33.946 30.525 34.363 40.73 4010 316992.53 229510 31.982 7.292 32.06 8.951 32.144 10.945 31.751 9.696 32.526 21.449 32.72 25.895 32.908 31.686 33.477 39.986 4045 316987.03 229544.1 31.629 7.304 31.715 8.969 31.812 10.96 31.462 9.731 32.259 21.485 32.51 25.942 32.624 31.046 33.406 40.095

4052.93 316983 229550.9 31.367 7.333 31.433 9.013 31.512 10.999 29.809 10.096 31.905 21.576 32.062 26.059 32.356 30.84 33.388 40.517 4068.12 316974.56 229563.6 29.625 7.421 29.755 9.141 29.897 11.114 28.488 15.951 30.531 21.842 30.746 26.235 30.941 30.552 31.274 39.749

4110 316951.09 229597.5 28.325 7.562 28.419 9.332 28.521 11.3 26.902 16.08 29.016 22.268 29.194 27.023 29.367 31.972 29.745 46.259 4240 316935.69 229726.4 26.392 7.644 26.522 9.421 26.656 11.412 25.259 16.247 27.264 22.505 27.503 28.698 27.75 32.257 28.337 47.357 4390 316893.38 229867.3 24.525 7.746 24.756 9.572 24.914 11.546 25.285 16.403 25.743 22.782 26.123 27.713 26.502 32.724 27.598 47.045 4435 316865.25 229902.3 24.526 7.837 24.767 9.707 24.93 11.667 21.15 16.403 25.781 23.059 26.155 28.231 26.536 33.144 27.626 47.77

4618.05 316767.75 230057 20.126 7.837 20.323 9.707 20.625 11.667 21.14 16.403 21.502 23.059 21.863 28.231 22.199 33.144 22.418 47.77 4634 316759.03 230070.4 20.1 7.837 20.3 9.707 20.61 11.667 21.14 16.403 21.49 23.059 21.85 28.231 22.19 33.144 22.4 47.77


Water Surface Profile Dundrum Slang - Present Day Scenario

0

10

20

30

40

50

60

70

80

90

0 1000 2000 3000 4000 5000 6000

Chainage (m)

Max

H

50% AEP Max H

20% AEP Max H

10% AEP Max H

4% AEP Max H

2% AEP Max H

1% AEP Max H

0.5% AEP Max H

0.1% AEP Max H


Dundrum Slang Side Channel

50% AEP 20%


AEP 0.1% AEP


(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Dundrum Slang_Side Channel Present Day

0 317146.34 226580.8 81.629 0.1 81.629 0.1 81.629 0.1 81.629 0.1 81.629 0.1 81.629 0.1 81.629 0.1 81.629 0.1 40 317159.31 226616.8 81.49 0.1 81.49 0.1 81.49 0.1 81.49 0.1 81.49 0.1 81.49 0.1 81.49 0.1 81.49 0.1

107.55 317159.97 226683.2 79.95 0.1 79.95 0.1 79.95 0.1 79.95 0.1 79.95 0.1 79.95 0.1 79.95 0.1 79.95 0.1 140 317160.69 226714.8 79.252 0.1 79.252 0.1 79.252 0.1 79.252 0.1 79.252 0.1 79.252 0.1 79.252 0.1 79.252 0.1

149.04 317159 226723.7 78.949 0.1 78.949 0.1 78.949 0.1 78.949 0.1 78.949 0.1 78.949 0.1 78.949 0.1 78.949 0.1 156.28 317156.94 226730.6 78.802 0.1 78.802 0.1 78.802 0.1 78.802 0.1 78.802 0.1 78.802 0.1 78.802 0.1 78.802 0.1

182 317144.47 226752.6 77.383 0.1 77.383 0.1 77.383 0.1 77.383 0.1 77.383 0.1 77.383 0.1 77.383 0.1 77.383 0.1 319.47 317109.25 226884.7 74.901 0.1 74.901 0.1 74.901 0.1 74.901 0.1 74.901 0.1 74.901 0.1 74.901 0.1 74.901 0.1

360 317105.22 226924.7 73.624 0.1 73.624 0.1 73.624 0.1 73.624 0.1 73.624 0.1 73.624 0.1 73.624 0.1 73.624 0.1 369.61 317105.31 226934.3 73.279 0.1 73.279 0.1 73.279 0.1 73.279 0.1 73.279 0.1 73.279 0.1 73.279 0.1 73.279 0.1 375.26 317105.34 226940 73.21 0.1 73.21 0.1 73.21 0.1 73.21 0.1 73.21 0.1 73.21 0.1 73.21 0.1 73.21 0.1

470 317108.03 227034.5 71.669 0.1 71.669 0.1 71.669 0.1 71.669 0.1 71.669 0.1 71.669 0.1 71.669 0.1 71.669 0.101 558 317120.88 227118.5 69.644 0.1 69.644 0.1 69.644 0.1 69.644 0.1 69.644 0.1 69.644 0.1 69.644 0.1 69.888 0.211

630.46 317124.38 227188.3 68.581 0.1 68.581 0.1 68.581 0.1 68.581 0.1 68.581 0.1 68.581 0.1 68.581 0.1 69.886 0.293 650 317117.63 227206.6 68.272 0.1 68.272 0.1 68.272 0.1 68.272 0.1 68.272 0.1 68.272 0.1 68.276 0.1 69.884 0.311

669.9 317112 227225.7 67.942 0.1 67.942 0.101 67.942 0.101 67.942 0.101 67.943 0.102 68.005 0.102 68.124 0.103 69.883 0.329 712 317100.09 227266 67.543 0.103 67.585 0.103 67.645 0.104 67.753 0.106 67.867 0.109 67.992 0.113 68.123 0.115 69.881 0.36

732.37 317094.31 227285.5 67.511 0.104 67.578 0.104 67.643 0.106 67.752 0.109 67.867 0.113 67.992 0.119 68.122 0.122 69.88 0.379 740.04 317092.91 227293 67.511 0.105 67.578 0.105 67.643 0.107 67.752 0.11 67.867 0.115 67.992 0.122 68.122 0.124 69.88 0.387 743.41 317093.56 227296.3 67.51 0.105 67.578 0.105 67.643 0.107 67.752 0.11 67.867 0.115 67.992 0.123 68.122 0.126 69.88 0.389 746.83 317094.28 227299.6 67.51 0.105 67.578 0.105 67.643 0.107 67.752 0.111 67.867 0.116 67.992 0.124 68.122 0.127 69.88 0.392

750 317094.97 227302.7 67.51 0.105 67.578 0.105 67.643 0.107 67.752 0.111 67.867 0.116 67.992 0.124 68.122 0.127 69.88 0.392


Water Surface ProfilesDundrum Slang Side Channel - Present Day Scenario

60

65

70

75

80

85

0 100 200 300 400 500 600 700 800

Chainage (m)

Max

H

50% AEP Max H

20% AEP Max H

10% AEP Max H

4% AEP Max H

2% AEP Max H

1% AEP Max H

0.5% AEP Max H

0.1% AEP Max H


Dodder Main Channel - Fluvial

50% AEP 20%


AEP 0.1% AEP


(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Dodder Main Channel Present Day

750 308806.16 223020.3 143.937 37.091 143.937 47.121 143.937 56.561 143.968 71.991 144.052 86.507 144.142 104.062 144.202 125.342 144.372 193.832 883.05 308822.47 223125.7 134.135 37.103 134.229 47.133 134.311 56.573 134.435 72.003 134.544 86.524 134.669 104.085 134.812 125.365 135.234 193.855 886.17 308824.88 223127.7 134.028 37.108 134.122 47.138 134.204 56.578 134.33 72.008 134.44 86.533 134.565 104.097 134.71 125.377 135.134 193.867 949.72 308874.03 223168 131.934 37.116 132.043 47.146 132.137 56.586 132.28 72.015 132.405 86.543 132.549 104.111 132.724 125.391 133.226 193.881 969.72 308889.5 223180.6 131.593 37.119 131.698 47.149 131.791 56.589 131.932 72.019 132.057 86.548 132.205 104.118 132.386 125.398 132.901 193.888 989.72 308902.53 223195.7 131.221 37.122 131.327 47.152 131.421 56.592 131.566 72.022 131.695 86.553 131.848 104.125 132.04 125.405 132.583 193.895 1009.72 308909.94 223214.2 130.712 37.125 130.828 47.155 130.933 56.595 131.098 72.025 131.244 86.557 131.411 104.129 131.619 125.409 132.219 193.899 1017.1 308911.06 223221.5 130.418 37.126 130.559 47.156 130.681 56.596 130.866 72.026 131.027 86.559 131.207 104.133 131.425 125.413 132.05 193.903 1029.71 308910.88 223234.1 130.199 37.13 130.337 47.16 130.459 56.6 130.644 72.03 130.802 86.565 130.98 104.14 131.195 125.42 131.807 193.91 1059.71 308900.81 223262.1 129.421 37.14 129.611 47.17 129.769 56.61 129.995 72.04 130.177 86.58 130.375 104.16 130.599 125.44 131.236 193.93 1149.71 308856.06 223339.8 128.539 37.162 128.709 47.192 128.841 56.632 129.016 72.062 129.162 86.613 129.328 104.204 129.52 125.484 130.117 193.974 1319.71 308788.06 223490.8 126.78 37.188 126.934 47.218 127.02 56.658 127.146 72.088 127.255 86.652 127.378 104.256 127.517 125.536 127.909 194.026 1459.71 308856.34 223607.9 125.107 37.207 125.251 47.237 125.407 56.677 125.571 72.107 125.707 86.681 125.857 104.295 126.023 125.575 126.498 194.064 1549.71 308823.75 223688.8 124.14 37.222 124.318 47.252 124.565 56.692 124.709 72.122 124.822 86.704 124.949 104.326 125.094 125.605 125.507 194.095 1639.71 308846.72 223760.9 123.331 37.236 123.46 47.267 123.575 56.707 123.729 72.136 123.861 86.725 124.007 104.354 124.172 125.633 124.603 192.542 1719.71 308865.13 223837 122.644 37.255 122.784 47.285 122.915 56.725 123.054 72.155 123.174 86.471 123.306 103.337 123.459 124.872 123.852 183.985 1859.71 308773.94 223932.6 120.755 37.279 120.886 47.309 121 56.749 121.178 72.179 121.331 86.775 121.497 104.418 121.665 125.389 122.16 194.205 2009.71 308851.31 224055.1 118.887 37.304 119.069 47.335 119.222 56.728 119.452 72.204 119.646 86.8 119.862 104.454 120.069 122.723 120.667 182.363 2159.72 308853.97 224196.5 117.592 37.325 117.784 47.356 117.947 56.749 118.185 72.219 118.373 86.808 118.579 104.126 118.776 121.769 119.349 178.009 2259.72 308929.28 224261.2 116.837 37.342 117.045 47.372 117.199 56.766 117.416 72.199 117.604 86.584 117.81 103.898 118.014 123.555 118.618 185.708 2359.72 308954.47 224354.3 116.242 37.357 116.464 47.387 116.612 56.767 116.814 71.986 117.005 86.544 117.225 103.885 117.458 123.104 118.174 177.56 2439.72 308980.38 224429.3 115.636 37.368 115.844 47.397 116.044 56.777 116.316 71.933 116.569 86.508 116.853 104.074 117.144 123.583 118.021 179.217 2486.2 309018.31 224455.6 115.292 37.373 115.554 47.402 115.782 56.782 116.102 71.937 116.388 86.514 116.699 104.201 116.995 125.412 117.826 194.715 2500.1 309026.72 224466.5 114.824 37.377 115.068 47.407 115.271 56.787 115.563 71.941 115.819 86.521 116.107 104.21 116.425 125.421 117.324 194.256 2531.4 309026.19 224497.1 109.454 37.382 109.583 47.411 109.693 56.791 109.854 71.945 109.996 86.527 110.157 104.219 110.338 125.429 110.863 194.227 2559.72 309023 224525.1 108.762 37.398 108.873 47.427 108.972 56.807 109.124 71.959 109.253 86.551 109.402 104.251 109.571 125.461 110.077 194.226 2719.72 309029.06 224678.5 106.018 37.424 106.279 47.453 106.499 56.833 106.818 71.983 107.025 86.59 107.257 104.303 107.514 125.512 108.224 194.282 2869.72 309062.59 224824.1 104.498 37.447 104.685 47.477 104.838 56.857 105.054 72.004 105.244 86.624 105.457 104.35 105.691 125.559 106.287 194.325 2999.72 309101.44 224937.4 103.54 37.467 103.706 47.497 103.84 56.877 104.013 72.024 104.167 86.655 104.342 104.391 104.534 125.599 105.038 194.361 3109.72 309048.94 225032.9 102.203 37.483 102.351 47.513 102.451 56.893 102.589 72.038 102.713 86.678 102.855 104.423 103.01 125.631 103.347 194.393 3189.72 309099.81 225089.7 101.296 37.506 101.443 47.535 101.566 56.916 101.707 72.059 101.831 86.712 101.969 104.469 102.118 125.675 102.52 194.433 3379.72 309150.25 225264.2 99.691 37.523 99.772 46.812 99.843 54.329 99.951 65.877 100.062 76.205 100.168 89.322 100.285 98.375 100.765 145.275 3409.72 309177.06 225277.3 99.34 37.14 99.457 47.563 99.558 56.937 99.7 70.339 99.848 80.447 99.968 91.712 100.12 102.972 100.656 145.426 3529.72 309283.69 225329.8 98.186 37.162 98.38 47.586 98.536 56.967 98.756 72.102 98.954 86.767 99.177 104.568 99.425 125.774 100.109 194.453 3679.72 309401.81 225420.9 97.355 37.186 97.572 47.61 97.732 56.991 97.945 72.125 98.136 86.803 98.356 104.615 98.601 125.823 99.258 194.503 3819.72 309482.09 225533 96.507 37.205 96.731 47.63 96.873 57.012 97.089 72.145 97.288 86.832 97.52 104.655 97.777 125.839 98.519 194.552 3909.72 309456.19 225618.6 95.873 37.223 96.092 47.649 96.274 57.005 96.535 71.963 96.77 86.229 97.03 103.348 97.316 123.717 98.11 187.285 4019.72 309457.88 225726.3 95.308 37.243 95.529 47.67 95.716 57.027 95.995 72.187 96.246 86.895 96.525 104.736 96.827 125.919 97.658 193.072 4099.71 309525.09 225758.3 94.922 55.875 95.132 69.623 95.314 82.547 95.584 102.981 95.826 122.087 96.096 145.161 96.388 172.245 97.209 257.912 4289.71 309547.09 225938.4 93.707 55.893 93.941 69.643 94.143 82.565 94.431 103.001 94.68 122 94.952 145.2 95.235 172.027 96.023 257.641 4349.71 309535.59 225996.5 93.257 55.902 93.485 69.651 93.682 82.573 93.963 103.009 94.207 122.012 94.47 145.216 94.741 172.043 95.501 257.649 4389.71 309559.84 226026.6 92.816 55.912 93.039 69.662 93.229 82.583 93.508 103.019 93.757 122.029 94.015 145.251 94.279 172.053 95.016 256.443 4479.71 309638.16 226069.3 91.804 55.927 92.022 69.5 92.219 82.57 92.503 101.506 92.765 118.007 93.011 131.627 93.254 144.638 93.868 182.034 4589.71 309671.06 226173.4 91.159 55.937 91.383 69.512 91.586 82.578 91.892 103.043 92.205 121.948 92.529 144.976 92.791 163.964 93.456 215.245

4650 309699.81 226226.2 90.928 55.948 91.178 69.525 91.402 82.588 91.727 103.057 92.006 121.968 92.322 145.003 92.566 163.97 93.172 215.245


50% AEP 20%


AEP 0.1% AEP


(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Dodder Main Channel Present Day (Cont’d)

4748.1 309749.34 226308.1 90.615 55.96 90.855 69.537 91.072 82.601 91.389 103.069 91.659 121.987 91.967 145.03 92.205 163.995 92.797 215.262 4795.68 309776.16 226344.6 82.097 55.973 82.289 69.553 82.455 82.614 82.695 103.083 82.904 122.009 83.142 145.057 83.362 164.027 84.032 215.493 4948.9 309892.09 226436.8 81.574 55.992 81.772 69.574 81.931 82.634 82.165 103.104 82.366 122.039 82.597 145.098 82.835 172.155 83.588 257.811 5053.1 309936.06 226530.9 80.774 56.008 80.958 69.591 81.12 82.65 81.356 103.121 81.561 122.063 81.793 145.131 82.021 172.189 82.641 257.842 5158.9 310009.44 226600.8 79.864 56.027 80.06 69.612 80.226 82.67 80.47 103.141 80.682 122.093 80.918 145.172 81.171 172.229 81.832 257.884 5308.9 310117.31 226695.4 78.999 56.051 79.207 69.637 79.358 82.694 79.589 103.165 79.791 122.128 80.013 145.221 80.246 172.272 80.829 257.931 5458.9 310237.91 226776.3 78.179 56.073 78.442 69.661 78.573 82.715 78.761 103.186 78.919 122.167 79.099 145.273 79.346 172.324 79.872 257.989 5598.9 310280.91 226909.2 77.625 51.453 77.755 62.74 77.873 73.852 78.046 91.486 78.191 107.356 78.364 126.643 78.633 161.33 79.161 237.781 5698.9 310321.22 227000.6 76.953 41.413 77.054 49.093 77.147 56.23 77.286 67.388 77.41 77.489 77.557 90.491 77.785 113.08 78.243 156.814 5798.9 310358.38 227093 76.037 34.145 76.14 38.35 76.228 41.196 76.363 43.905 76.476 47.161 76.629 51.617 76.797 58.366 77.359 86.206 5898.9 310443.41 227140.4 75.425 18.227 75.661 19.126 75.855 19.702 76.137 34.275 76.332 38.199 76.576 41.394 76.799 62.26 77.425 90.753 6008.9 310547.81 227162.8 75.368 49.467 75.592 58.576 75.73 67.176 75.924 79.968 76.108 90.098 76.327 102.602 76.501 111.807 77.062 156.781 6139 310633.25 227258.7 74.824 55.376 75.009 67.894 75.142 77.192 75.322 92.009 75.464 103.854 75.633 117.228 75.897 131.512 76.441 165.46

6268.9 310730 227343.8 74.332 47.825 74.49 54.374 74.617 59.549 74.783 63.902 74.933 66.541 75.178 76.98 75.423 84.594 76.059 128.689 6408.9 310763.25 227464.6 73.879 55.597 74.109 67.682 74.281 76.775 74.538 92.741 74.746 107.752 74.996 127.441 75.224 156.144 75.751 215.636 6558.9 310819.88 227568.9 73.271 56.023 73.46 69.553 73.611 81.918 73.807 100.731 73.978 116.741 74.137 134.803 74.346 152.024 74.785 202.489 6648.9 310893.19 227619.8 72.713 62.141 72.893 73.494 73.036 83.879 73.234 99.473 73.382 113.118 73.574 129.758 73.716 146.865 74.152 200.914 6728.9 310922.28 227692.8 71.986 65.361 72.096 79.018 72.182 91.862 72.321 112.03 72.442 130.201 72.576 151.535 72.701 175.639 72.966 232.552 6818.9 311007.06 227716 71.509 65.278 71.514 78.931 71.518 91.858 71.527 112.585 71.536 132.032 71.549 154.944 71.572 184.312 71.633 266.803 6938.9 311127.41 227727.4 70.721 65.347 70.895 78.695 71.033 91.991 71.222 111.534 71.363 128.661 71.507 146.606 72.219 184.014 72.04 223.282 7050 311237.09 227739.3 70.082 39.384 70.16 46.055 70.237 52.621 70.352 62.49 70.461 71.749 70.58 81.944 71.775 183.946 71.023 119.751

7121.7 311302.91 227749.3 63.564 48.205 63.818 58.739 64.044 69.542 64.41 86.175 64.766 101.876 64.997 120.319 65.099 184.004 65.953 193.034 7174.8 311355.5 227743.8 63.394 65.441 63.64 78.85 63.856 92.145 64.206 113.105 64.545 132.957 64.768 156.017 64.942 184.102 65.703 268.358 7218.6 311398.69 227749.1 63.115 65.462 63.358 78.863 63.575 92.181 63.963 113.163 64.317 133.033 64.54 156.092 64.797 184.162 65.433 268.54 7254.5 311431.56 227763.5 62.972 65.479 63.226 78.889 63.448 92.21 63.773 113.211 64.19 133.097 64.417 156.155 64.677 184.203 65.296 268.69 7284.5 311458.88 227775.9 62.833 65.543 63.087 78.958 63.31 92.323 63.634 113.39 64.048 133.346 64.28 156.383 64.545 184.379 65.172 269.246 7498.9 311658.78 227850.2 61.925 65.628 62.169 79.073 62.389 92.471 62.706 113.629 62.978 133.667 63.257 156.71 63.565 184.821 64.235 269.987 7608.9 311753.5 227900.7 61.413 65.699 61.649 79.174 61.865 92.598 62.18 113.828 62.447 133.933 62.721 156.979 63.014 185.193 63.59 270.608 7768.9 311892.78 227975.6 60.322 65.777 60.555 79.28 60.768 92.733 61.078 114.042 61.332 134.227 61.585 157.268 61.863 185.586 62.332 238.242 7898.9 311995.91 228053.9 59.41 65.845 59.63 79.378 59.826 92.854 60.118 114.233 60.344 132.653 60.551 152.935 60.822 185.924 61.346 229.14 8028.9 312098.66 228132.5 58.647 65.909 58.849 79.418 59.024 92.942 59.301 114.335 59.545 134.403 59.759 157.665 59.993 186.222 60.632 272.327 8137.9 312187.28 228194.5 58.05 65.943 58.248 79.464 58.431 93.001 58.754 114.429 59.03 134.493 59.21 157.802 59.397 186.373 59.945 272.606 8155.7 312200.56 228206.3 57.939 65.977 58.137 79.512 58.321 93.061 58.662 114.525 58.949 134.573 59.146 157.93 59.365 186.496 59.851 272.953 8268.9 312286.72 228279.6 57.19 66.044 57.378 79.607 57.555 93.179 57.81 114.711 58.039 134.825 58.337 158.173 58.626 186.812 59.145 269.345 8408.9 312409.06 228337.4 56.428 65.388 56.587 77.34 56.736 88.921 56.95 105.754 57.135 121.674 57.334 139.68 57.73 187.192 58.16 233.122 8568.9 312530.28 228239.3 55.375 66.197 55.6 79.815 55.805 93.44 56.1 114.808 56.338 134.276 56.585 156.448 56.956 187.541 57.483 259.606 8688.9 312632.53 228186.6 54.707 65.721 54.919 78.705 55.114 91.124 55.39 110.692 55.623 128.417 55.855 147.665 56.252 187.794 56.751 228.739 8768.9 312686.41 228244.1 54.18 66.296 54.398 79.945 54.598 93.53 54.881 114.398 55.113 134.055 55.331 155.063 55.687 188.021 56.244 241.434 8868.9 312714.13 228339.5 53.263 66.348 53.476 80.019 53.667 93.674 53.935 114.609 54.142 132.04 54.377 151.076 54.656 188.273 55.175 233.661 8968.9 312711.97 228438.2 52.698 66.402 52.887 80.094 53.056 93.768 53.3 115.704 53.518 136.164 53.74 159.635 53.988 188.53 54.616 270.271 9068.9 312702.19 228536.3 52.158 66.445 52.344 80.153 52.508 93.578 52.743 114.008 52.954 135.239 53.171 158.142 53.428 188.743 54.063 262.95


50% AEP 20%


AEP 0.1% AEP



9128.9 312732.41 228586.5 51.857 66.474 52.022 80.197 52.175 93.897 52.395 115.89 52.593 136.412 52.805 159.84 53.049 188.89 53.675 281.101 9180 312782.88 228590.6 51.763 66.503 51.911 80.236 52.043 93.946 52.226 115.985 52.378 136.521 52.542 159.884 52.723 189.034 53.302 281.378

9268.9 312870.56 228580.5 49.076 66.545 49.291 80.295 49.491 94.019 49.772 116.103 50.002 136.675 50.24 160.04 50.57 189.242 51.241 281.761 9308.9 312909.06 228569.7 48.89 66.574 49.117 80.336 49.324 94.069 49.613 116.184 49.848 136.787 50.093 160.143 50.442 189.384 51.138 280.271 9378.9 312961.25 228524.5 48.575 66.608 48.824 80.384 49.042 94.13 49.326 116.271 49.545 136.919 49.773 160.225 50.111 189.551 50.787 282.589 9438.9 313007.19 228489.1 48.269 66.635 48.513 80.422 48.734 94.171 49.027 116.279 49.256 135.684 49.502 158.022 49.864 189.68 50.527 271.854 9478.9 313040.13 228508 48.097 66.672 48.327 80.474 48.533 94.238 48.804 114.111 49.024 131.115 49.262 151.189 49.622 189.861 50.24 249.849 9578.9 313022.94 228604.2 47.33 66.712 47.54 80.529 47.723 93.795 48.01 116.454 48.25 137.293 48.495 160.61 48.812 190.051 49.49 265.577 9628.9 313023.66 228652.4 47.085 66.738 47.314 80.561 47.516 93.841 47.825 116.53 48.067 137.392 48.31 160.713 48.634 190.179 49.302 279.241 9678.9 313053.19 228692.8 46.824 66.767 47.033 80.397 47.211 93.396 47.487 115.452 47.711 135.603 47.933 158.809 48.248 190.318 48.812 262.48 9738.9 313094.84 228734.2 46.541 66.494 46.742 79.647 46.921 92.041 47.198 112.84 47.419 131.473 47.644 153.091 47.952 190.444 48.554 257.555 9778.9 313133.03 228745.9 46.277 66.814 46.488 80.673 46.673 93.981 46.96 116.753 47.175 136.365 47.42 158.132 47.719 190.559 48.273 261.052 9828.9 313178.59 228731 45.931 66.84 46.145 80.709 46.333 94.027 46.618 115.76 46.841 134.87 47.072 155.474 47.352 190.686 47.933 247.125 9878.9 313203.88 228688 45.616 66.864 45.822 80.746 45.997 94.033 46.274 116.926 46.499 136.813 46.708 155.926 46.964 190.818 47.56 237.393 9928.9 313243.94 228660.5 45.415 66.728 45.617 80.785 45.788 94.085 46.054 116.993 46.277 137.85 46.493 160.662 46.745 190.964 47.352 267.817 9988.9 313302.41 228670.6 45.102 66.775 45.297 80.852 45.463 94.168 45.724 117.112 45.944 138.002 46.152 160.968 46.404 191.198 47.019 281.694 10106.6 313415.72 228699.5 44.5 66.828 44.685 80.922 44.844 94.261 45.085 117.087 45.292 138.233 45.493 161.544 45.738 191.461 46.275 279.388 10189.9 313490.38 228736.4 43.988 66.866 44.183 80.974 44.348 94.276 44.591 116.971 44.802 137.372 45.005 159.79 45.252 191.646 45.756 263.733 10248.7 313538.13 228769.8 43.599 66.917 43.785 81.046 43.941 94.367 44.181 117.245 44.398 138.459 44.597 161.043 44.842 191.895 45.348 266.294 10381.2 313591.44 228890.6 42.346 66.955 42.514 81.1 42.657 94.434 42.886 117.265 43.125 138.586 43.312 162 43.533 192.081 44.067 283.043 10392 313595.28 228900.6 42.275 66.959 42.447 81.105 42.587 94.441 42.81 117.274 43.05 138.6 43.231 161.999 43.447 192.098 43.973 283.141

10394.2 313596.09 228902.7 42.263 66.961 42.43 81.107 42.569 94.444 42.791 117.279 43.031 138.606 43.208 162.002 43.422 192.106 43.94 283.167 10398.3 313597.59 228906.5 42.233 66.974 42.398 81.126 42.536 94.467 42.756 117.315 42.996 138.656 43.165 162.05 43.378 192.169 43.887 283.293 10443.2 313617.34 228946.6 41.234 66.998 41.409 81.161 41.563 94.51 41.802 117.386 42.004 138.751 42.197 162.146 42.445 192.289 43.047 287.144 10492.5 313663.19 228944.3 40.948 67.033 41.124 81.209 41.277 94.571 41.516 117.483 41.716 138.883 41.907 162.275 42.157 192.454 42.735 287.476 10573.4 313740.78 228927 40.334 67.086 40.523 81.282 40.686 94.665 40.937 117.63 41.144 138.687 41.329 158.627 41.589 192.704 42.115 269.545 10690.9 313857.53 228938.9 39.2 67.181 39.399 81.417 39.574 94.832 39.839 117.888 40.053 139.046 40.275 162.824 40.547 193.137 41.165 287.285 10932.5 314067 229039 38.33 67.263 38.485 81.532 38.658 94.969 38.889 118.085 39.059 139.332 39.274 163.07 39.603 193.431 40.174 281.885 10986.4 314103.22 229079 38.193 67.315 38.344 81.604 38.524 95.05 38.755 118.196 38.918 139.5 39.136 163.245 39.484 193.595 40.004 289.057 11104.9 314191.66 229156.6 37.843 94.208 38 108.424 38.216 130.144 38.466 159.817 38.627 180.975 38.86 213.394 39.082 252.132 39.74 351.171 11240.2 314284.91 229252.7 37.29 94.285 37.464 108.533 37.697 130.283 37.982 160.046 38.171 181.631 38.444 215.271 38.716 252.515 39.405 359.462 11399 314271.66 229407.7 36.444 94.347 36.619 108.626 36.815 130.4 37.056 160.234 37.214 181.882 37.441 215.523 37.662 252.838 38.252 371.678

11490.1 314253.5 229496.7 35.967 94.349 36.144 108.63 36.31 130.404 36.505 160.241 36.628 181.892 36.804 215.532 36.986 252.85 37.479 371.704 11525.6 314259.59 229531.4 35.726 94.348 35.88 108.629 36.047 130.404 36.239 160.241 36.356 181.891 36.523 215.537 36.696 252.848 37.155 371.712 11568 314278 229569.6 35.461 94.348 35.581 108.628 35.732 130.225 35.92 159.407 36.037 180.471 36.202 212.886 36.375 252.846 36.82 363.059 11573 314280.56 229573.9 35.378 94.346 35.501 108.627 35.647 130.225 35.835 159.406 35.952 180.472 36.117 212.93 36.286 252.844 36.732 363.103 11688 314377.38 229634.3 34.598 94.346 34.683 108.627 34.807 130.404 34.976 160.239 35.092 181.892 35.248 215.531 35.386 252.844 35.84 371.567 11750 314435.44 229655.8 34 94.346 34 108.627 34 130.404 34 160.239 34 181.892 34 215.531 34 252.844 34 371.567 11760 314444.53 229658 34.927 94.343 35.087 108.625 35.314 130.401 35.599 160.233 35.787 181.848 36.014 209.168 36.277 240.272 37.35 371.557 11805 314488.94 229665.2 34.773 94.341 34.927 108.624 35.145 130.4 35.427 160.232 35.618 181.847 35.859 209.167 36.15 240.271 37.262 371.555

11882.6 314566.31 229662.7 34.458 94.335 34.602 108.62 34.81 130.396 35.076 160.225 35.259 181.84 35.48 209.164 35.721 240.405 36.729 371.539 12084.8 314764.88 229658.2 31.473 94.31 31.684 108.588 31.935 130.373 32.245 160.205 32.348 181.812 32.535 209.595 32.789 250.307 33.767 371.509 12389.6 315069 229658.6 31.105 94.296 31.298 108.552 31.508 130.357 31.77 160.088 31.815 194.656 31.969 227.501 32.186 274.796 33.082 371.483


50% AEP 20%


AEP 0.1% AEP



12585.7 315257.13 229603.8 30.753 94.206 30.954 108.386 31.124 130.316 31.373 160.056 31.346 133.602 31.405 141.369 31.486 147.344 32.581 371.426 12756.8 315413.31 229538.6 30.269 100.401 30.469 115.981 30.618 132.277 30.833 159.888 30.98 172.28 31.071 186.957 31.193 208.243 32.059 371.832 12896 315528.81 229591.1 29.745 100.396 30.014 115.941 30.154 132.269 30.375 153.164 30.415 184.203 30.477 197.804 30.558 219.036 31.846 371.684

12986.9 315554.44 229675.9 29.432 100.395 29.73 115.475 29.87 131.526 30.142 157.126 30.127 156.533 30.207 164.766 30.287 176.592 31.802 371.542 13050 315570.34 229736.1 29.347 100.397 29.512 115.471 29.662 132.182 29.943 162.109 30.01 157.127 30.128 159.558 30.255 160.876 31.656 371.459 13087 315588.31 229768.5 29.187 100.404 29.349 115.472 29.493 132.189 29.755 162.114 29.826 157.126 29.954 159.543 30.107 160.806 31.483 371.474 13148 315619.41 229821 28.968 100.411 29.115 115.472 29.242 132.197 29.48 162.122 29.611 157.129 29.776 159.516 29.967 160.742 31.259 371.428

13192.5 315647.56 229854.9 28.884 100.355 29.018 115.321 29.161 131.942 29.399 161.007 29.514 172.931 29.668 186.941 29.831 203.618 31.347 371.372 13299.7 315751.59 229873.3 26.974 100.373 27.143 115.341 27.306 132.176 27.555 162.146 27.762 189.691 28.038 220.054 28.238 260.002 29.763 371.506 13421 315866.97 229846.5 26.595 100.388 26.732 115.355 26.863 132.192 27.076 162.162 27.245 189.718 27.415 220.089 27.616 260.307 29.599 371.098 13517 315953.78 229805.5 26.215 98.957 26.311 111.552 26.399 124.04 26.539 143.355 26.654 156.719 26.784 171.1 26.955 190.447 29.334 370.616 13559 315994.75 229798.8 26.073 94.406 26.152 103.347 26.233 112.362 26.373 126.488 26.502 137.164 26.65 148.42 26.875 177.282 29.464 370.488

13631.4 316054.31 229835.5 25.778 94.173 25.891 102.213 26.005 110.023 26.199 123.154 26.37 134.359 26.557 146.647 26.803 195.772 29.408 370.864 13724.4 316059.94 229925.5 25.309 100.383 25.448 115.037 25.586 130.932 25.806 157.298 25.991 179.406 26.183 200.343 26.431 302.567 29.219 371.129 13795 316063.69 229995.4 24.764 100.391 24.929 115.296 25.09 131.94 25.324 160.596 25.52 184.58 25.734 210.947 28.316 259.266 29.135 371.15 13832 316078.38 230029.3 24.569 100.397 24.694 115.301 24.825 131.946 25.03 160.571 25.212 181.986 25.419 202.498 25.659 235.131 28.351 371.679

13869.6 316102.78 230057.5 24.585 100.415 24.71 115.319 24.837 131.068 25.031 152.116 25.226 166.244 25.463 181.817 25.679 201.564 28.432 373.348 14006.9 316217.22 230025.9 22.717 91.257 22.922 98.958 23.153 105.325 23.594 112.365 24.017 116.083 24.432 120.902 24.713 142.151 27.962 376.02 14110.1 316312.34 229990.9 22.559 100.331 22.844 115.103 23.142 132.098 23.645 162.052 24.084 189.137 24.482 214.953 24.784 235.449 28.082 380.523 14282.3 316480.59 230021.1 21.433 100.338 21.729 115.117 22.108 132.129 22.601 161.947 22.79 188.988 23.045 215.772 23.261 235.387 27.245 379.325 14337.4 316535.06 230029.4 21.211 100.345 21.519 115.118 21.916 132.124 22.451 161.942 22.626 188.991 22.896 216.893 23.13 238.647 27.244 380.164 14400 316597.41 230034.8 21.116 100.354 21.422 115.123 21.817 132.119 22.348 161.948 22.499 189.001 22.754 218.749 22.98 242.454 27.315 372.46 14500 316694.31 230056.4 20.695 100.377 21.008 115.138 21.371 132.115 21.875 162.098 21.924 189.029 22.129 218.948 22.337 244.577 27.01 370.427 14700 316790.25 230189.5 19.743 104.486 20.226 120.849 20.705 137.672 21.237 157.025 20.993 148.051 20.989 147.928 21.083 151.293 26.743 368.883 14818 316838.34 230297.2 17.714 104.495 17.948 120.936 18.175 139.117 18.508 172.606 18.098 148.19 18.142 148.524 18.252 151.698 21.746 368.453 14838 316846.5 230315.5 17.602 104.497 17.829 120.936 18.043 139.12 18.356 172.593 17.964 148.193 18.007 148.528 18.115 151.703 21.724 368.459 14858 316854.63 230333.7 17.597 104.502 17.83 120.93 18.05 139.126 18.362 172.536 17.942 148.685 17.992 149.145 18.113 152.634 21.549 368.372 14950 316891.47 230418 17.312 101.61 17.532 117.398 17.731 134.462 18.003 164.096 17.527 166.844 17.575 173.242 17.69 189.284 21.132 368.643 15070 316948.84 230522.9 17.173 101.887 17.443 117.538 17.672 134.832 17.962 166.451 17.049 95.843 17.101 98.233 17.218 104.216 21.214 493.487 15297 317147.53 230596.1 16.005 104.497 16.206 120.423 16.414 137.791 16.785 170.363 16.411 121.21 16.437 121.267 16.503 121.354 18.947 368.885 15500 317322.09 230681.8 15.478 104.519 15.68 120.91 15.893 139.15 16.279 172.573 15.918 141.08 15.962 144.867 16.067 153.906 18.864 368.17 15620 317440.13 230661.4 15.101 104.533 15.321 120.923 15.561 139.164 15.988 172.586 15.586 141.101 15.638 144.891 15.77 153.934 18.688 368.199 15683 317492.78 230691.1 14.873 104.552 15.041 120.942 15.218 139.183 15.53 172.606 15.237 141.131 15.273 144.923 15.363 153.973 17.258 368.22 15875 317574.94 230861.1 12.836 104.573 12.979 120.957 13.115 139.194 13.323 172.113 13.206 146.694 13.246 152.455 13.337 166.482 14.613 368.19

15982.5 317566.47 230967.9 12.473 104.585 12.623 120.916 12.78 138.916 12.992 164.565 12.918 155.496 12.961 160.715 13.056 172.614 14.512 368.077 16026.5 317593.75 230993.1 8.408 104.589 8.636 120.909 8.87 139.212 9.254 172.641 9.517 180.368 9.618 188.076 9.91 206.476 11.947 367.28 16192.9 317696.66 231122.8 7.938 104.604 8.185 120.918 8.433 139.228 8.809 172.66 9.066 200.071 9.164 213.728 9.444 249.895 11.644 366.71 16297.4 317763 231203.6 7.549 104.563 7.786 121.062 8.025 139.329 8.419 172.728 8.655 199.716 8.744 213.754 9.014 249.921 11.412 366.401 16369.8 317807.66 231260.5 7.139 95.518 7.379 144.088 7.634 161.123 8.035 189.197 8.3 208.113 8.371 211.832 8.571 227.779 11.26 366.038 16480.3 317864.59 231354.7 7.103 104.948 7.361 120.719 7.603 139.576 8.006 174.021 8.217 200.161 8.294 211.997 8.415 227.792 10.47 365.834 16528.4 317877.56 231400.8 6.974 104.691 7.206 120.981 7.446 139.325 7.821 172.725 8.01 198.124 8.098 208.683 8.19 228.417 10.265 365.593 16634 317867.69 231505.9 6.651 104.701 6.873 120.999 7.103 139.329 7.455 171.879 7.61 191.745 7.681 198.988 7.763 213.346 9.959 365.242 16797 317807.69 231655.2 6.3 104.714 6.522 121.008 6.748 139.343 7.101 170.358 7.286 182.988 7.368 185.198 7.441 190.768 10.078 364.658

16892.1 317755.72 231734.7 6.082 104.723 6.296 121.016 6.512 139.352 6.852 170.359 7.032 187.845 7.129 193.612 7.23 198.955 10.092 364.31


50% AEP 20%


AEP 0.1% AEP



16945 317743.06 231785.9 5.916 104.736 6.125 121.026 6.341 139.364 6.688 170.452 6.857 186.356 6.953 193.538 7.056 200.213 9.898 363.76 17079.2 317763 231916.9 5.554 104.747 5.744 121.036 5.944 139.375 6.294 170.769 6.476 186.586 6.584 193.871 6.704 200.388 9.99 362.962 17116.5 317780.56 231949.8 5.482 104.751 5.668 121.039 5.864 139.379 6.212 170.777 6.394 186.654 6.504 194.253 6.624 202.114 9.974 362.782 17138.3 317790.94 231968.9 5.408 104.76 5.592 121.047 5.785 139.388 6.136 170.696 6.319 186.544 6.432 194.364 6.55 202.194 9.948 363.034 17241.7 317841.97 232058.8 5.028 104.774 5.203 121.061 5.39 139.402 5.742 171.792 5.928 187.631 6.047 197.315 6.161 206.426 9.805 363.105 17330 317884.16 232136.2 4.568 104.788 4.741 121.074 4.926 139.416 5.361 185.657 5.529 204.266 5.674 221.546 5.796 233.358 9.72 362.847

17427.9 317901.03 232231.5 4.484 104.804 4.676 121.087 4.894 139.43 5.268 171.434 5.47 187.458 5.597 197.472 5.726 207.507 9.582 364.335 17570 317891.91 232373 4.235 104.822 4.435 121.104 4.669 139.448 5.082 170.556 5.315 186.556 5.459 196.488 5.619 207.174 9.695 394.428

17669.5 317892.28 232470 3.668 104.835 3.849 121.113 4.061 139.459 4.414 170.543 4.57 186.565 4.65 196.483 4.721 207.2 7.728 365.887 17792 317926.13 232587.7 3.326 104.853 3.491 121.129 3.693 139.475 4.034 170.553 4.183 186.579 4.257 196.506 4.322 207.24 7.447 364.285

17925.3 318010.63 232690.4 3.079 104.873 3.221 121.143 3.421 139.49 3.777 170.555 3.919 186.632 3.979 196.322 4.019 204.798 7.631 367.478 18070 318084.41 232811.1 2.876 119.799 2.984 121.162 3.164 139.508 3.5 170.519 3.641 181.772 3.702 185.981 3.742 191.26 7.545 373.575 18264 318185.03 232967.1 2.836 134.084 2.915 164.212 3.064 139.538 3.349 170.471 3.471 181.775 3.519 184.045 3.539 183.963 6.791 359.804 18390 318283.69 233042.5 2.806 104.946 2.866 121.214 2.989 139.552 3.21 170.474 3.3 181.791 3.34 184.062 3.357 183.991 4.998 359.164

18491.8 318268.41 233139.8 2.669 104.964 2.708 121.234 2.795 139.57 2.99 170.5 3.075 181.81 3.111 184.098 3.13 184.024 4.793 358.589 18601.8 318228.69 233242.4 2.626 104.983 2.661 121.255 2.698 139.588 2.872 170.519 2.954 181.83 2.996 184.126 3.022 184.055 4.746 358.344 18691.8 318196.16 233326.3 2.598 105.001 2.632 121.275 2.65 139.605 2.809 170.521 2.884 181.85 2.928 184.151 2.956 184.621 4.699 357.973 18801.8 318156.41 233428.8 2.488 105.02 2.542 121.296 2.558 139.624 2.655 170.527 2.705 181.877 2.75 184.181 2.782 184.119 3.468 357.954 18901.8 318120.28 233522.1 2.469 105.036 2.514 121.315 2.516 139.641 2.596 170.533 2.641 181.905 2.687 184.211 2.721 184.148 3.328 357.937 18991.8 318087.75 233606 2.439 105.054 2.459 121.334 2.46 139.658 2.502 170.566 2.531 181.932 2.589 184.244 2.633 184.179 3.093 357.957 19101.8 318048 233708.6 2.429 288.616 2.454 290.75 2.455 139.684 2.495 296.661 2.525 299.973 2.578 305.901 2.619 310.417 2.978 357.933

19303.27 317991 233901 2.435 105.11 2.454 121.392 2.446 139.714 2.497 170.682 2.525 182.044 2.578 184.366 2.616 184.287 2.835 358.048 19482.02 317960.81 234077.2 2.425 105.129 2.45 123.778 2.45 139.733 2.49 170.727 2.517 182.079 2.567 184.405 2.607 184.32 2.755 358.13 19589.17 317950.34 234183.5 2.42 105.13 2.44 123.851 2.44 139.733 2.48 170.727 2.51 182.079 2.56 184.405 2.6 184.32 2.731 358.131

19594 317950.66 234188.4 2.42 105.13 2.44 123.851 2.44 139.733 2.48 170.727 2.51 182.079 2.56 184.405 2.6 184.32 2.73 358.131


Water Surface ProfileDodder Main Channel - Present Day Scenario

0

20

40

60

80

100

120

140

160

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000

Chainage (m)

Max

H

50% AEP Max H

20% AEP Max H

10% AEP Max H

4% AEP Max H

2% AEP Max H

1% AEP Max H

0.5% AEP Max H

0.1% AEP Max H


Dodder Main Channel Tidal Data

Tidal Return Period 50% AEP 20%


AEP 0.1% AEP


(mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) (mOD) (m3/s) Dodder Main Channel Present Day

15500 317322.09 230681.8 15 68.925 15.205 83.326 15.313 91.522 15.495 105.923 15.47 103.923 15.47 103.923 15.47 103.923 15.367 95.621 15620 317440.13 230661.4 14.614 68.929 14.82 83.345 14.931 91.523 15.119 105.928 15.093 103.919 15.093 103.919 15.093 103.919 14.986 95.633 15683 317492.78 230691.1 14.475 68.941 14.644 83.393 14.734 91.54 14.889 105.973 14.867 103.944 14.867 103.944 14.867 103.944 14.779 95.675 15875 317574.94 230861.1 12.468 68.936 12.629 83.353 12.72 91.539 12.848 105.95 12.831 103.944 12.831 103.944 12.831 103.944 12.759 95.659

15982.5 317566.47 230967.9 12.117 68.962 12.267 83.34 12.349 91.575 12.487 105.975 12.469 104.02 12.469 104.02 12.469 104.02 12.389 95.681 16026.5 317593.75 230993.1 7.875 68.95 8.097 83.465 8.218 91.617 8.427 105.963 8.398 103.982 8.398 103.982 8.398 103.982 8.277 95.692 16192.9 317696.66 231122.8 7.36 68.909 7.6 83.674 7.731 91.752 7.96 105.944 7.929 103.977 7.929 103.977 7.929 103.977 7.795 95.776 16297.4 317763 231203.6 6.964 68.9 7.212 84.052 7.349 92.05 7.573 106.227 7.543 104.275 7.543 104.275 7.543 104.275 7.414 95.955 16369.8 317807.66 231260.5 6.533 86.599 6.788 103.557 6.927 113.026 7.155 128.662 7.123 126.527 7.123 126.527 7.123 126.527 6.993 117.602 16480.3 317864.59 231354.7 6.527 68.9 6.785 85.272 6.923 92.521 7.152 106.503 7.121 104.636 7.121 104.636 7.121 104.636 6.99 96.505 16528.4 317877.56 231400.8 6.384 68.987 6.654 84.485 6.78 92.219 6.997 106.391 6.968 104.45 6.968 104.45 6.968 104.45 6.843 96.259 16634 317867.69 231505.9 6.086 68.945 6.339 83.997 6.463 91.95 6.672 106.211 6.644 104.248 6.644 104.248 6.644 104.248 6.523 96.015 16797 317807.69 231655.2 5.723 68.931 5.981 83.791 6.107 91.85 6.319 106.148 6.29 104.176 6.29 104.176 6.29 104.176 6.168 95.93

16892.1 317755.72 231734.7 5.526 68.941 5.776 83.742 5.896 91.814 6.099 106.127 6.072 104.152 6.072 104.152 6.072 104.152 5.955 95.897 16945 317743.06 231785.9 5.383 68.935 5.624 83.696 5.738 91.801 5.934 106.11 5.907 104.133 5.907 104.133 5.907 104.133 5.793 95.885

17079.2 317763 231916.9 5.066 68.96 5.281 83.648 5.388 91.768 5.569 106.09 5.545 104.109 5.545 104.109 5.545 104.109 5.441 95.851 17116.5 317780.56 231949.8 5.017 68.967 5.217 83.63 5.321 91.755 5.497 106.083 5.474 104.099 5.474 104.099 5.474 104.099 5.372 95.838 17138.3 317790.94 231968.9 4.951 68.973 5.147 83.609 5.249 91.741 5.423 106.074 5.4 104.089 5.4 104.089 5.4 104.089 5.3 95.824 17241.7 317841.97 232058.8 4.602 68.999 4.781 83.573 4.877 91.72 5.042 106.059 5.019 104.07 5.019 104.07 5.019 104.07 4.924 95.804 17330 317884.16 232136.2 4.146 68.977 4.322 83.537 4.417 91.696 4.582 106.042 4.559 104.052 4.559 104.052 4.559 104.052 4.464 95.781

17427.9 317901.03 232231.5 4.03 68.974 4.221 83.517 4.323 91.687 4.499 106.038 4.474 104.045 4.474 104.045 4.474 104.045 4.373 95.772 17570 317891.91 232373 3.779 68.958 3.969 83.466 4.071 91.657 4.249 106.013 4.225 104.017 4.225 104.017 4.225 104.017 4.122 95.738

17669.5 317892.28 232470 3.218 68.99 3.428 83.448 3.549 91.653 3.738 106.031 3.754 104.054 3.797 104.146 3.844 104.191 3.876 95.931 17792 317926.13 232587.7 2.935 69.087 3.124 83.488 3.237 91.73 3.411 106.126 3.442 104.177 3.497 104.363 3.558 104.463 3.637 96.256

17925.3 318010.63 232690.4 2.754 69.437 2.935 83.816 3.049 92.055 3.219 106.453 3.283 104.56 3.364 104.864 3.45 105.113 3.581 97.045 18070 318084.41 232811.1 2.633 69.846 2.793 87.1 2.9 96.641 3.053 119.376 3.136 120.116 3.232 119.936 3.331 120.274 3.496 101.692 18264 318185.03 232967.1 2.624 70.964 2.779 117.127 2.882 131.387 3.027 176.456 3.117 182.527 3.214 181.99 3.306 183.287 3.468 139.221 18390 318283.69 233042.5 2.614 71.62 2.765 85.613 2.863 93.614 3.008 107.884 3.089 106.432 3.18 107.516 3.266 108.262 3.426 100.716

18491.8 318268.41 233139.8 2.539 71.932 2.679 86.129 2.767 94.112 2.888 108.39 2.992 106.87 3.095 107.779 3.19 108.781 3.371 101.293 18601.8 318228.69 233242.4 2.522 72.881 2.658 87.12 2.744 94.659 2.857 108.975 2.967 107.351 3.076 108.413 3.174 109.614 3.364 102.312 18691.8 318196.16 233326.3 2.509 73.771 2.644 87.484 2.727 96.265 2.836 110.835 2.948 108.792 3.059 109.65 3.159 110.181 3.354 104.261 18801.8 318156.41 233428.8 2.491 76.351 2.632 88.117 2.711 95.884 2.809 110.214 2.922 108.662 3.008 109.572 3.105 111.126 3.304 103.919 18901.8 318120.28 233522.1 2.482 76.465 2.619 88.512 2.697 96.493 2.792 110.822 2.907 109.315 2.995 110.296 3.092 112.037 3.295 104.733 18991.8 318087.75 233606 2.462 76.807 2.597 89.484 2.67 97.177 2.76 111.533 2.879 110.009 2.969 110.991 3.069 112.914 3.279 105.771 19101.8 318048 233708.6 2.465 247.912 2.592 307.218 2.674 182.899 2.762 213.373 2.883 210.634 2.973 197.696 3.073 210.922 3.282 346.766

19303.27 317991 233901 2.457 80.443 2.597 93.737 2.665 101.708 2.753 114.418 2.874 112.937 2.964 114.222 3.064 115.852 3.273 109.315 19482.02 317960.81 234077.2 2.461 85.492 2.586 98.789 2.672 105.245 2.762 117.854 2.882 116.852 2.972 117.099 3.071 119.343 3.28 113.193 19589.17 317950.34 234183.5 2.46 86.621 2.58 100.214 2.67 106.658 2.76 119.312 2.88 118.261 2.97 118.56 3.07 120.228 3.28 114.286

19594 317950.66 234188.4 2.46 86.621 2.58 100.214 2.67 106.658 2.76 119.312 2.88 118.261 2.97 118.56 3.07 120.228 3.28 114.286


Water Surface Profile - Tidal EventsDodder Main Channel - Present Day Scenario

0

2

4

6

8

10

12

14

16

18

15000 15500 16000 16500 17000 17500 18000 18500 19000 19500 20000

Chainage (m)

Max

H

50% AEP Max H

20% AEP Max H

10% AEP Max H

4% AEP Max H

2% AEP Max H

1% AEP Max H

0.5% AEP Max H

0.1% AEP Max H

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RIVER DODDER CATCHMENT FLOOD RISK MANAGEMENT PLAN · A. Jackson A. Jackson West Pier 9/7/2010 River...

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