Shannon Catchment-based Flood Risk Assessment and Management (CFRAM) Study

Inception Report – Unit of Management 24

Final Report

11 July 2012

Document control sheet

Client: Office of Public Works Project: Shannon CFRAM Study Job No: 32103000 Document Title: Inception Report Unit of Management 24

Originator Checked by Reviewed by Approved by

ORIGINAL NAME NAME NAME NAME v0_0 James Murray Iain Blackwell Iain Blackwell Mike Hind DATE SIGNATURE SIGNATURE SIGNATURE SIGNATURE 29-Jul -11

Document Status Draft Inception Report

REVISION NAME NAME NAME NAME V0_A Soon Hock Lee Iain Blackwell Iain Blackwell Peter Smyth DATE SIGNATURE SIGNATURE SIGNATURE SIGNATURE 09-Dec -11

Document Status Draft Final Inception Report

REVISION NAME NAME NAME NAME V1_0 Iain Blackwell James Murray James Murray Peter Smyth

DATE SIGNATURE SIGNATURE SIGNATURE SIGNATURE 11-Jul-12

Document Status Final Inception Report

Copyright Copyright Office of Public Works. All rights reserved.

No part of this report may be copied or reproduced by any means without prior written permission from the Office of Public Works. If you have received this report in error, please destroy all copies in your possession or control and notify the Office of Public Works .

Legal Disclaimer This report is subject to the limitations and warranties contained in the contract between the commissioning party (Office of Public Works) and Jacobs Engineering Ireland Limited.

Contents

Glossary 1

1 Introduction 2 1.1 Scope 2 1.2 Structure of the Inception Report 2 1.3 National Flood Risk Assessment and Management Programme 3 1.4 Shannon CFRAM Study and Flood Risk Management Plans 4 1.5 Shannon CFRAM Study Area 5 1.6 Unit of Management HA24 7 1.6.1 Catchment Description 7 1.6.2 Areas of Potential Significant Risk 9 1.6.3 Individual Risk Receptors 9

2 Detailed Methodology 11 2.1 Introduction 11 2.2 Project Management 11 2.2.1 Management Arrangements 11 2.2.2 Web-Based Work Platform: Sharepoint 12 2.2.3 Project Website 13 2.2.4 Health and Safety 13 2.2.5 Technical Training 13 2.3 Data Collection 14 2.3.1 Summary of Work Completed 14 2.3.2 Constraints, Data Problems and Other Issues 14 2.3.3 Amendments to Methodology 14 2.4 Flood Risk Review 14 2.4.1 Summary of Work Completed 14 2.4.2 Constraints, Data Problems and Other Issues 15 2.4.3 Amendments to Methodology 15 2.5 Surveys 16 2.5.1 Summary of Work Completed 16 2.5.2 Constraints, Data Problems and Other Issues 17 2.5.3 Amendments to Methodology 18 2.6 Hydrological Analysis 18 2.7 Hydraulic Analysis 19 2.7.1 Summary of Work Completed 19 2.7.2 Constraints, Data Problems and Other Issues 21 2.7.3 Amendments to Methodology 21 2.8 Flood Risk Assessment 21 2.8.1 Summary of Work Completed 21 2.8.2 Constraints, Data Problems and Other Issues 21 2.8.3 Amendments to Methodology 22 2.9 Environmental Assessment 22 2.9.1 Summary of Work Completed 25 2.9.2 Constraints, Data Problems and Other Issues 25 2.9.3 Amendments to Methodology 26

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2.10 Consultation and Engagement 26 2.10.1 Summary of Work Completed 26 2.10.2 Constraints, Data Problems and Other Issues 28 2.10.3 Amendments to Methodology 28 2.11 Development of Flood Risk Management Options 29 2.11.1 Summary of Work Completed 29 2.11.2 Constraints, Data Problems and Other Issues 29 2.11.3 Amendments to Methodology 30 2.12 Flood Risk Management Plan Preparation 30

3 Data and Data Requirements 31 3.1 Objectives 31 3.2 Data Collection Methodology 31 3.2.1 OPW Datasets 31 3.2.2 External Data Requests 31 3.2.3 Stakeholder Meetings 33 3.2.4 Future Flood Events 33 3.3 Data Review 33 3.3.1 Data Quality 33 3.3.2 Outstanding Data 35 3.3.3 Quality, Adequacy, and Interpretation of Data 35

4 Survey Requirements 37 4.1 Defence Asset Data 37 4.1.1 Asset Identification 37 4.1.2 Location of Assets Within APSRs 37 4.1.3 Location of Assets Outside APSRs 40 4.2 Survey Specification 41

5 Preliminary Hydrological Assessment and Method Statement 42

6 Inception Phase Conclusions and Summary 43

Appendix A Extracts from the Project Brief

Appendix B Preliminary Hydrological Assessment and Method Statement

Appendix C Data Register

Appendix D External Data Requests

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Figures

Figure 1 Shannon RBD and its Units of Management 6 Figure 2 Shannon Estuary South Unit of Management 8 Figure 3 Unit of Management Overview 10 Figure 4 Screen shot of Project Website 13 Figure 5 Model Groupings Unit of Management 24 20 Figure 6 Stages of the SEA associated with the development of the FRMP 23 Figure 7 Relationship between the Study tasks and Outputs of the SEA and AA processes 24 Figure 8 Assets outside APSR boundaries – UoM 24 east 40 Figure 9 Assets outside APSR boundaries – UoM 24 west 40

Tables

Table 1-A Summary of APSR Recommendations from the Draft Flood Risk Review 9 Table 2-A Co-ordination and commercial responsibility 12 Table 2-B Organisations with Access to Sharepoint 12 Table 2-C Indicative number of cross sections, structures and area of 2D model extent in each of the UoM 24 model groups 19 Table 2-D Summary of Stakeholder Meetings 27 Table 3-A Summary of Organisations Consulted 32 Table 3-B Key Data Quality Issues 34 Table 3-C Outstanding Data 36 Table 4-A Potential Flood Defence Assets in UoM 24 39

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Glossary

CAR Community at Risk A location considered to have a probable significant flood risk, based on the understanding of the location, prior to the Flood Risk Review.

AFRR Area for Flood Risk A location considered to have a possible Review significant flood risk, based on the understanding of the location prior to the Flood Risk Review.

APSR Area of Potential An area at potentially significant risk, Significant Risk taking account of both likelihood of flooding and consequence.

UoM Unit of Management The division of the study area into major catchments and their associated coastal areas.

RBD River Basin District The natural geographical and hydrological units for water management, as defined during the implementation of the Water Framework Directive.

PFRA Preliminary Flood Risk A high level screening exercise that Assessment identified areas of potentially significant flood risk from all sources, and summarises the probability and harmful consequences of past (historical) and future (potential) flooding.

CFRAM Catchment-based Flood The five year study covering the whole Study Risk Assessment and River Shannon catchment area which Management Study gives a picture of past flooding and areas at risk of future flooding, and set out a prioritised set of specific measures for reducing and managing flood risk .

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1 Introduction

1.1 Scope

The specification for the Inception Report is set out in Section 2.4.2 of the Stage I Project Brief (June 2010) with a separate Inception Report required for each Unit of Management.

The overriding purpose of the Inception Report is to provide a summary of the findings in the study to date, with specific reference to the data collected, its analysis, and how these early study findings are likely to influence the methodology used in the study for the various tasks required under the Shannon CFRAM study.

Based on the extract from the Project Brief (as included in Appendix A) the focus of the Inception Report is on the following key items:

• Detailed Methodology – including constraints and any amendments to the methodology for each key task or discipline • Data and Data requirements • Survey Requirements • Preliminary Hydrological Assessment and Method Statement

The Inception Report provides a summary of the project status as at the end of July 2011, six months into the study. It should be noted that this snapshot in time is maintained for the Draft Final and Final Inception Reports, as inevitably, many aspects move on in the intervening period.

1.2 Structure of the Inception Report

The structure of the Inception Report is based on the specific items identified in Section 2.4.2 of the Stage I Project Brief as follows.

Section 1 – Introduction

This section provides the introduction and background to the National Flood Risk Assessment and Management Programme, project, the Shannon CFRAM study and specifically to this Unit of Management.

Section 2 - Detailed Methodology

This section covers each of the major discipline areas involved on the project, and for each discipline includes identification of any critical constraints, data problems and other issues that might give rise to opportunities or risks to the Project, and further detail of, or proposed amendments to, the methodologies proposed for use in delivery of the Project.

Section 3 - Data and Data Requirements

This section includes details covering:

• data identified, collected, provided and reviewed and a description of the quality, fitness-for-purpose and interpretation of such data;

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a list of outstanding data required, including data sources, critical dates, likely data costs, and the potential detrimental impacts on the Project in the event of this data not being made available; and

a description of the data which is, and will be, unavailable, the impacts of this absence of data on the Project, and how it is proposed to overcome the problems arising.

Section 4 - Survey Requirements

This section includes preliminary details of the flood defence assets within the Study Area including maps, and provides reference to the survey specifications for channel, structures and defence asset geometric surveys in the Study Area.

Section 5 - Preliminary Hydrological Assessment & Method Statement

This section includes a brief introduction to the context for the Preliminary Hydrological Assessment and Method Statement.

Section 6 Inception Phase Conclusions and Summary

This section includes the main conclusions and summary points for each of the project tasks.

Within the Shannon CFRAM Study, there are a series of five Inception Reports, each covering a different Unit of Management. As each of the Inception Reports needs to be a stand-alone document, there are a significant number of common sections to the reports, as the issues or the approach adopted for the study, are the same across the entire RBD.

Section 1.6 of the Inception Report is specific to the Unit of Management to which the report relates.

Throughout the rest of the Inception Report, those sections of the report that have issues, methodology, or other aspects that are specific to the Unit of Management, are identified through the use of a single black line to the right of the paragraphs of interest, as indicated for this paragraph.

It is noted that this Inception Report refers to Areas of Potential Significant Risk (APSR). During the Inception Stage of the Shannon CFRAM study this term was redefined as Area for Further Assessment (AFA). For future activities on this study it should be noted that the term APSR will be replaced by the term Area for Further Assessment (AFA). Within the context of the Inception Stage, and this report specifically, the term APSR has been maintained throughout for consistency with other documents prepared during the Inception Stage, notably the Flood Risk Review Report.

1.3 National Flood Risk Assessment and Management Programme

Flood risk in Ireland has historically been addressed through the use of engineered arterial drainage schemes and/or flood relief schemes. In line with internationally changing perspectives, the Government adopted a new policy that has shifted the emphasis in addressing flood risk towards:

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• a catchment-based context for managing risk; • pro-active flood hazard and risk assessment and management; and • increased use of non-structural and flood impact mitigation measures.

A further influence on the management of flood risk in Ireland is the EU Floods Directive (2007/60/EC) which aims to reduce the adverse consequences of flooding on human health, the environment, cultural heritage and economic activity.

To implement the flood-related Government policy and legislative requirements, CFRAM Studies will be undertaken for those RBDs defined for the purpose of the EU Water Framework Directive which contain catchments within the Republic of Ireland.

Each CFRAM Study will focus on areas known to have experienced fluvial and/or coastal flooding in the past and areas subject to significant development pressure both now and in the future in each river catchment area.

By 2015, Ireland must establish Flood Risk Management Plans (FRMPs) focused on prevention, protection and preparedness for areas identified to be at significant risk of flooding.

1.4 Shannon CFRAM Study and Flood Risk Management Plans

The OPW has commissioned the Shannon CFRAM Study to assess and develop FRMPs. The FRMPs will help to manage the existing flood risk in the Study Area, taking account of the potential future significant increases in this risk due to climate change, ongoing development and other pressures that may arise in the future.

This study will deliver upon many of the principal requirements of the EU Floods Directive; in particular the requirements set out in Articles 6, 7 and 8 and Annex A relating to flood mapping and flood risk management plans. The objectives of the Shannon CFRAM Study are to: • Identify and map the existing and potential future flood hazard within the Study Area; • Assess and map the existing and potential future flood risk within the Study Area; • Identify viable structural and non-structural options and measures for the effective and sustainable management of flood risk in APSRs and within the catchment as a whole; and • Prepare a set of FRMPs for the Study Area and associated Strategic Environmental Assessment and, as necessary, Habitats Directive (Appropriate) Assessment.

The FRMPs will set out the policies, strategies, measures and actions that should be pursued by the relevant bodies (including the OPW, local authorities and other stakeholders) to achieve the most cost-effective and sustainable management of existing and potential future flood risk within the Study Area. This in turn will take account of potential environmental effects, environmental plans, objectives and legislative requirements and other statutory plans and requirements.

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1.5 Shannon CFRAM Study Area

The Shannon RBD (the “Study Area”) is the largest RBD in Ireland, covering approximately 17,800 km 2 and more then 20% of the island of Ireland. The RBD includes the entire catchment of the River Shannon and its estuary as well as some catchments in North Kerry and West Clare that discharge directly to the Atlantic.

The Shannon River rises in the Cuilcagh Mountains, at a location known as the Shannon Pot in the counties of Cavan and Fermanagh. The river flows in a southerly direction before turning west and discharging through the Shannon Estuary to the Atlantic Ocean between counties Clare and Limerick. While the River Shannon is 260 km long from its source to the head of the Shannon Estuary in Limerick City, over its course the river falls less then 200 m in elevation. The Shannon RBD is characterised as an ‘International RBD’ as it extends into Northern Ireland. However, there are no areas identified as being at significant flood risk in the Shannon RBD within Northern Ireland, and no significant cross-border issues.

Significant tributaries of the Shannon include the Inny, Suck and Brosna. There are several lakes in the RBD, including Lough Ree, Lough Derg and Lough Allen.

Other important rivers within the RBD include the Maigue, Deel and Feale discharging into the Shannon Estuary from the south, and the Fergus, Owengarney (or Ratty) and Cloon discharging into the estuary from the north. The RBD includes parts of 17 counties: Limerick, Clare, Tipperary, Offaly, Westmeath, Longford, Roscommon, Kerry, Galway, Leitrim, Cavan, Sligo, Mayo, Cork, Laois, Meath and Fermanagh. While much of the settlement in the RBD is rural there are six significant urban centres within the RBD - Limerick City, Ennis, Tralee, Mullingar, Athlone and Tullamore.

As defined under the Water Framework Directive (WFD) where the study area comprises a RBD, this is divided further into Units of Management (UoM). The UoMs constitute major catchments or river basins (typically greater than 1000km 2) and their associated coastal areas, or conglomerations of smaller river basins and their associated coastal areas. The Shannon RBD (and by definition the Shannon CFRAM Study Area) and the Units of Management within the Shannon RBD are shown in Figure 1. There are five Units of Management (UoM) within the Study Area, as marked on Figure 1:

Tralee Bay – Feale (Hydrometric Area 23 – ‘HA23’) – UoM 23
Shannon Estuary South - (Hydrometric Area 24 – ‘HA24’) – UoM 24
Shannon Upper and Lower (Hydrometric Area 25 & 26 – ‘HA25-26’) – UoM 25-26
Shannon Estuary North (Hydrometric Area 27 – ‘HA27’) – UoM 27
Mal Bay (Hydrometric Area 28 – ‘HA-28’) – UoM 28

FRMPs and associated flood mapping will be developed for the whole of the Shannon RBD and reported to the European Commission as required under the EU Floods Directive.

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Figure 1 Shannon RBD and its Units of Management

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1.6 Unit of Management HA24

1.6.1 Catchment Description

This Inception Report is for Shannon Estuary South Unit of Management. Separate Inception Reports are prepared for each of the other four Units of Management.

The ‘Shannon Estuary South’ Unit of Management (or UoM 24) is shown in Figure 2 and encompasses areas of four counties; Kerry, Limerick, Cork and Tipperary. It consists of a fertile limestone plain, known as the ‘Golden Vale’ bounded on the north by the Shannon Estuary and on the west and south and east by the Mulllaghareirk Mountains, Ballyhoura Mountains, Galty Mountains and Slieve Felim Mountains.

The Unit of Management (referred to as UoM 24) is dominated by two main river catchments, the Deel and the Maigue, which together cover 65% of the Unit of Management. The coastline extends along the Shannon Estuary from Limerick City in the east to where it meets the Atlantic Ocean between Loop Head (on the north of the Shannon Estuary in County Clare) and Kerry Head (County Kerry), to the west of this Unit of Management.

The River Deel rises in the Mullaghareirk Mountains near Dromina. It flows roughly in a north-westerly direction though the mountains, where it is joined by numerous tributaries, including the Finglasha River and the Ahavarragh Stream which drains the lands upstream of Dromcolliher. Downsteam of Newcastle West, the River Deel is joined by the Rivers Arra, Dooally and Daar, which drain the steep topography of the Knockanimpaha Mountains which bound the west of the catchment. Downstream of the confluence the River Deel flows north east, through agricultural plains and roughly follows the direction of the N21 towards and through the centre of Rathkeale. Flowing north from Rathkeale the Deel flows through Askeaton, and on to the Shannon Estuary. Where the River Deel enters the Shannon Estuary, the catchment area is approximately 486.1 km 2.

The Deel catchment drainage scheme was completed in 1968 and focused on improved drainage for agricultural purposes.

East of the Deel catchment, and bounded to the north by the River Blackwater catchment, lies the Maigue catchment. The River Maigue drains an area of approximately 806 km 2, from its source in the Ballyhoura Mountains (County Cork) to where it enters the Shannon Estuary approximately 10km north of Adare.

Rising north of Milford in north Cork, the River Maigue flows east to join the River Loobagh approximately 3km north of Charleville, and then flows north through Bruree. Just downstream of Bruree, the Maigue is joined by the significant tributary of the Morningstar River, which drains a catchment area of approximately 131.9 km 2. Continuing northwards, just upstream of Croom, the Maigue is joined by the third significant tributary of the River Camogue. From Croom, the River Maigue flows north-west towards Adare where the River Maigue becomes tidally influenced.

Arterial Drainage schemes have historically been undertaken at various locations within the Maigue and Deel catchments for agricultural purposes.

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Figure 2 Shannon Estuary South Unit of Management

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1.6.2 Areas of Potential Significant Risk

The Stage II Project Brief identified Communities at Risk (CAR) and Areas for Flood Risk Review (AFRR). One of the early activities on the Shannon CFRAM Study has been to undertake a Flood Risk Review for all of these locations, as well as several additional locations, not included in the Stage II Project Brief. Full details are given in the Draft Flood Risk Review Report.

One of the primary objectives of the Flood Risk Review has been to identify which of the CAR and AFRR should be designated as Areas of Potential Significant Risk (APSR). The Draft Flood Risk Review Report (June 2011) recommends the identification of APSRs in UoM 24 as shown in Table 1-A. The locations of the CARs and AFRRs are shown on Figure 3.

CAR or Recommendation Site ID Name County AFRR in from Draft Flood Brief Risk Review CAR 3 Adare Limerick CAR APSR CAR 4 Askeaton Limerick CAR APSR CAR 9 Ballylongford Kerry CAR APSR AFRR 11 Bruff Limerick AFFR Not APSR AFRR 12 Bruree Limerick AFRR APSR CAR 20 Charleville Cork CAR APSR CAR 22 Clarina Limerick CAR APSR CAR 24 Croom Limerick CAR APSR CAR 25 Drumcolligher Limerick CAR APSR CAR 29 Foynes Limerick CAR APSR CAR 32 Kildimo New Limerick CAR Not APSR AFRR 25 Killacolla Limerick AFFR Not APSR CAR 35 Kilmallock Limerick CAR APSR AFRR 42 Milford Cork AFRR APSR AFRR 33 Monaster Limerick AFFR Not APSR Newcastle CAR 44 Limerick CAR APSR West AFRR 37 Patrickswell Limerick AFFR Not APSR CAR 50 Rathkeale Limerick CAR APSR Table 1-A Summary of APSR Recommendations from the Draft Flood Risk Review

1.6.3 Individual Risk Receptors

A number of assets within the Shannon RBD have been identified as Individual Risk Receptors (IRRs). These assets located outside of an Area of Potential Significant Risk and if flooded, would give rise to significant detrimental impact or damage. One individual risk receptor (IRR) is located within UoM 24, Tarbert Power Station. This is shown on Figure 3.

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Figure 3 Unit of Management Overview

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2 Detailed Methodology

2.1 Introduction

For each of the main tasks and technical discipline areas involved in the study, each of the following sub-sections summarises:

• any critical constraints, data problems or other issues that have been identified that might give rise to opportunities for, or risks to, the Project; and

• further detail of, or proposed amendments to, the methodologies proposed for use in delivery of the Project based on the enhanced familiarity with the Study Area and with the data collected over the start-up period of the Project.

The disciplines covered are based on the Stage I Project Brief and cover the following:

• Project Management • Data Collection • Flood Risk Review • Surveys • Hydrological Analysis • Hydraulic Analysis • Flood Risk Assessment • Environmental Assessment • Consultation and Engagement • Development of Flood Risk Management Options • Preparation of a Flood Risk Management Plan

This section of the report is intended to give a brief overview in relation to each task. Subsequent sections of the report give greater detail on some of the main tasks that have been a particular focus of the early stages of the Shannon CFRAM study, namely Data, Surveys, and Hydrological Analysis.

2.2 Project Management

Our general approach to Project Management is the implementation of a programme based philosophy supported by tools such as Risk and Opportunities Register, Organisational Chart, Issues Chart and Meeting Actions. All this information is available to OPW for viewing on the web based platform; Sharepoint.

Details included below apply across all Units of Management within the Shannon RBD, and provide the context for some specific comments in relation to this Unit of Management.

2.2.1 Management Arrangements

We have adopted a matrix approach to the management of our Shannon CFRAM Study commissions. Discipline Leads have responsibility for technical delivery of

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tasks, with co-ordination and commercial responsibility shared as shown in Table 2-A below.

Title - Name Description Area

Project Director Ultimate responsibility for All the delivery of the project, with a particular focus on quality.

Project Manager Primary point of contact and All lead on our ‘programme management’ approach.

Area FRMP delivery lead Area leads are responsible UoM 23, 24, 27 and 28 (South) for delivery of aspects within their designated UoMs. They are also responsible for developing Area FRMP delivery lead an understanding and UoM 25/26 (North) familiarity with issues specific to the individual UoM.

Table 2 -A Co-ordination and commercial responsibility

2.2.2 Web-Based Work Platform: Sharepoint

A web-based portal for the distribution of documents and information to Jacobs, OPW and Local / Regional Authority staff has been developed utilising the Microsoft Sharepoint package.

The portal is located at http://ipe.jacobs.com/ShannonCFRAM and is accessible to all named OPW, Jacobs and Local / Regional Authority staff.

Permissions vary according to the organisation and the document being viewed. The portal has been structured such that documents may be restricted to Jacobs staff only and/or Jacobs and OPW staff only, as well as being open to all named accounts. The organisations with access to Sharepoint (in addition to Jacobs and OPW) are listed in Table 2-B.

Organisation Mid-West Regional Authority Limerick County Council South -west Regional Authority Longford County Council Midlands Regional Authority Meath County Council Clare County Council Offaly County Council Galway County Council Roscommon County Council Kerry County Council Sligo County Council Laois County Council Tipperary North County Council Leitrim County Council Westmeath County Council Limerick City Council Table 2-B Organisations with Access to Sharepoint

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2.2.3 Project Website

We have developed a Project Website an extract of which is shown in Figure 4.

Figure 4 Screen shot of Project Website

2.2.4 Health and Safety

Our approach to Health and Safety has been as outlined in our Tender Stage 1 submission. We can confirm that, to date, there have been no incidents or injuries during delivery of this project.

We have been appointed PSDP for the project by OPW. It was agreed with OPW that the gauging station survey contract did not require a PSDP appointment.

Team members have undergone working near / on water health and safety training which is relevant to most of the on-site work that will be carried out over the course of this project.

Our method statements and risk assessments for our extensive site visits during the first six months of the study have been updated to reflect new risks identified as the study has progressed.

2.2.5 Technical Training

A Technical Note, reference 32103000/TD23 V0.0, was issued to OPW on the 9 th June 2011. This Note outlines our proposed approach to enhance technical understanding and capacity and facilitate effective engagement of those involved with the Project. We shall develop, prepare and deliver a programme of technical training which will be applicable for the Shannon CFRAM Study but can also be applied generically for other CFRAM Studies.

See Technical Note 32103000/TD23 V0.0 for further details.

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2.3 Data Collection

An overview of the data collection completed to date is presented in the following sections. Further detail is given in Section 3 of this report.

The progress and issues related to Data Collection, as outlined below, is best considered within the context of the entire Shannon RBD.

2.3.1 Summary of Work Completed

Consultations have been undertaken with OPW and other stakeholders to obtain data relevant to the study. Consultations have been completed via:

• Gap analysis of datasets provided by OPW following the Inception Meeting of the 26 th January 2011; • Submission of External Data Requests to stakeholders including OPW, Local Authorities, Regional Authorities, ESB, Met Eireann and Waterways Ireland; and • Stakeholder meetings, following up on External Data Requests where necessary.

2.3.2 Constraints, Data Problems and Other Issues

Data quality and outstanding data issues affecting each particular discipline are detailed for each specific discipline within Section 2 and are also summarised in Section 3.

2.3.3 Amendments to Methodology

No amendments have been made to the proposed methodology outlined at tender stage.

2.4 Flood Risk Review

The specification for the Flood Risk Review is set out in Section 4 of the Stage I Project Brief (June 2010) and Section 2.11 of the Stage II Shannon CFRAM Study Project Brief (October 2010).

The Flood Risk Review site visits are now complete and the draft report has been submitted to OPW for review, which contains details of all Units of Management.

2.4.1 Summary of Work Completed

The Draft Flood Risk Review Report recommends locations in the Shannon RBD that are considered to be Areas of Potential Significant Risk (APSR). OPW, in consultation with the Local Authorities, will use the findings of this Draft Flood Risk Review Report to confirm the final APSR list, following which the extent and direction for all future activities on the project will be set.

In total, 107 locations were considered in the Draft Flood Risk Review Report. This comprised 57 Communities at Risk (CAR) and 50 Areas for Flood Risk Review (AFRR), as defined in the Project Brief and through subsequent minor additions. These locations were identified by OPW based on a national Preliminary Flood Risk Assessment.

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The Flood Risk Review has included a desk-based assessment of each location taking account of the Preliminary Flood Risk Assessment findings, and a range of readily available datasets. A visit to each location has further informed the assessment.

The findings from the PFRA have been reviewed both in terms of the desk-based study and a ground truthing site visit. In general, verification of receptors and flood hazard extents was found to be good, although some areas of uncertainty at specific locations have been identified.

The desk-based assessment combined with the site visit for each location has been the basis for concluding whether the location should be identified as an APSR or not.

For this UoM, the sites visited under the Flood Risk Review activity, and the recommended designation of each location (as an APSR or not) are listed in Table 1-A in Section 1.6.2 of this Inception Report.

2.4.2 Constraints, Data Problems and Other Issues

The Draft Flood Risk Review report is now completed and there are no outstanding constraints, data problems or other issues related to our current scope. However, it is recognised that there is a possibility that we may be requested by OPW to undertake further Flood Risk Review assessments, and these would be an addition to the scope.

The site visits undertaken highlighted some important considerations around the watercourses identified in the EPA “Blue Line” network. Issues include watercourses identified by the “Blue Line” that are not considered to pose a fluvial flood risk, as well as other watercourses not identified by the “Blue Line” that are considered to give a fluvial flood risk. This is important in terms of the significant cost of survey of these channels, and to ensure that the watercourses which will be hydraulically modelled are appropriate.

2.4.3 Amendments to Methodology

Our approach was based on the proposals we have set out in our Stage I and Stage II tender responses to meet the requirements of the Project Brief. This approach was further reiterated and outlined in the Technical Note; Flood Risk Review Method Statement; reference 32103000/TD3 V0.0.

While there were no significant amendments to the Methodology described in our Stage I and Stage II tender responses and the Note referred to above there were some minor revisions to the Desktop Review and Site Visit Evaluation Pro-forma. These amendments were based on improving presentation as the review developed, the only noteworthy change being the removal of the Threshold Site Visit Review Score (SRVS).

Initially the Threshold SRVS was proposed as a cut off point above which a site would be considered for designation as an APSR. This was removed following discussions which confirmed that the SRVS was appropriate for informing designation but the final decision on designation would ultimately come down to engineering judgment by our FRR Team leads.

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2.5 Surveys

Survey is considered in further detail in Section 4 of this report.

In the sections below, the specific requirements of this UoM are, in several respects, linked to wider survey considerations across the rest of the RBD. Where necessary, specific reference is made to this UoM within the context of these wider considerations.

2.5.1 Summary of Work Completed

(a) Methodology Summary

Our methodology has been reviewed and refined in the context that all the survey works are on the critical path of the project. We have elected to adopt a different approach to the works we directly manage so as to minimise possible disruption due to the delay in topographic survey information. Our approach is detailed in (c) below.

(b) Defence Asset Condition Survey

We have gathered relevant data and undertaken an overview of the extent of Defence Assets within APSRs. We will be developing more detailed survey requirements in the coming months.

(c) Channel and Structure Survey

We identified in our tender submission that we considered that the gathering of survey information is a significant element in this critical part of the delivery of this project. We have focussed on various measures to try to reduce this risk as well as identifying areas where information gathering can be accelerated.

Initially we agreed that the most efficient approach would be to adopt the contract documents that OPW had commissioned from JBA for the survey requirements for (amongst other areas) Units of Management 25 and 26, the northern fluvial part of the Shannon RBD.

On receipt of a copy of the draft document in early May 2011 we put forward various suggestions regarding the approach to the procurement in our technical note No. 32103000/TD016 V0.0.

We developed a survey procurement strategy in our Technical note 16 issued on 20 April 2011 which we believed had been accepted although recent discussions around the survey of Defence Assets suggest that our recommendations have not been fully adopted.

Following further discussions with OPW it was agreed that the southern survey contracts, which Jacobs were responsible for managing on behalf of OPW, should adopt the Department of Finance Conditions of Engagement for Consultancy Services (Technical) (CoE1) for the survey contract. It is considered that these conditions are more robust for managing contractors within tight timescales and strict provisions for payment based on final acceptable deliverables have been introduced along with Liquidated Damages for late delivery. A programme for delivery will be included in the contract that dovetails into the model build programme so as to allow efficient use of modelling resources. Our Technical note 32103000/TD030 V0.0 provides further details of our approach.

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Furthermore we proposed that two contracts should be let for the southern area so as to increase the rate of delivery of surveying services. We were concerned that in the current depressed market, resources are severely depleted and the programme might be influenced by the performance of a single survey contractor. We believe that this policy has been employed now on the northern contract.

We have proposed small advance contracts for undertaking surveys of the 16 southern gauging stations and the Ballylongford APSR. The former is to give early access to the hydrologists of gauging information and production of calibration curves for out of bank flows. The latter is part of proposals to advance Unit of Management 24 as a pilot study for the wider project. This work will be procured from tenderers who have responded to a PQQ process designed and implemented by Jacobs. The details of the PQQ responses and our recommendations are included in our technical note 32103000/TD029 V0.0. Two contracts will be awarded. It is anticipated that survey work on these advance contracts could start in late September 2011 with results available by Christmas 2011.

The procurement process for the main OJEU contracts has been delayed by the need to construct contracts in such a way as to maximise the value obtained from the survey work including the management of delivery of survey information in a manner integrated into the main project programme. It is anticipated that the OJEU survey contract will not deliver model build information before January 2012.

Our technical notes 32103000/TD016 V0.0 and 32103000/TD030 V0.0 proposed a strategic procurement approach as well as proposing a variety of measures to minimise the risk of delay in the provision of survey information to the main project.

In summary our approach to date has been based on minimising the risk of delays to the overall project by maximising the access to survey resource, developing robust conditions of contract to manage the performance of the survey contractors and bringing forward specific requirements into small contracts in advance of the OJEU contracts.

(d) Floodplain Survey

The majority of the floodplain survey will be undertaken by LiDAR under a contract to be let by OPW. In the channel survey contracts we have proposed extended cross-sections beyond the minimum 20m specified requirement where necessary to provide an accurate tie-in to the LiDAR information.

(e) Property Survey

We have yet to identify vulnerable properties that may require threshold level information.

2.5.2 Constraints, Data Problems and Other Issues

We have noted that there will be a substantial number of photographs generated by the survey specification requirements and we have raised the issue as to how these should be referenced for future access. We would propose that the cross section photographs should be included within Table D6.2 of Appendix D of the specification.

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2.5.3 Amendments to Methodology

(a) Methodology Summary

We have agreed that the Southern Gauging stations and Balllylongford APSR should be procured as advance contracts to give early access to the model build teams. This will allow them to develop the appropriate protocols in advance of the main survey works being delivered.

(b) Defence Asset Condition Survey

We are reviewing the information obtained during the flood risk reviews to ascertain the best way of undertaking these surveys.

(c) Channel and Structure Survey

We do not envisage any substantial change in the channel and structure survey other than contractual options to accelerate progress.

(d) Floodplain Survey

We do not envisage any substantial change in the floodplain survey pending the delivery of the LiDAR information.

(e) Property Survey

We anticipate that the survey approach where required will be developed once flood levels have been established.

2.6 Hydrological Analysis

The hydrological analysis forms a major part of the Inception Report, as indicated in the Inception Report requirements listed in Section 2.4.2 of the Stage I Project Brief.

In the early part of the Shannon CFRAM Study, a major emphasis has been placed on the hydrological aspects as this has a fundamental bearing on the future approaches to be used on the study in terms of developing suitable flood flow estimates to feed in to the hydraulic model, which ultimately leads to the preparation of one of the key study deliverables – the flood extent and flood hazard maps.

The work undertaken for the hydrological analysis to date will form the basis of a significant part of the Hydrological Report, scheduled for delivery in 2012. For this reason the hydrological aspects of the Inception Report are developed as a stand alone report – the Preliminary Hydrological Assessment and Method Statement - which is included as Appendix B to this Inception Report.

This has the advantage of providing a solid basis for agreeing the content of the Hydrological Report, which is to be confirmed through the National Technical Co- ordination Group.

The specific requirements of this section of the Inception Report are covered in detail in the Preliminary Hydrological Assessment and Method Statement. These requirements are:

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• Identification of critical constraints, data problems and other issues that may give rise to opportunities or risks to the project; and

• Detail of, or proposed amendments to, the methodologies proposed for use in delivery of the study.

2.7 Hydraulic Analysis

2.7.1 Summary of Work Completed

We have divided the reaches requiring modelling into model groups. In some cases we propose to use a single model to represent an entire river catchment. However, for larger catchments we have divided the model reaches into separate models, based on an assessment of the number of cross sections, structures and likely areas of 2D modelling required. The area of likely 2D model extent is an indicative estimate based on the area of existing flood map present within an APSR boundary. The groupings have been selected so that the predicted model run times are computationally manageable.

A total of 44 models have been planned for the whole Shannon RBD, numbered N1- N21 in the North (UoM 25/26) and S 1 – S23 in the South (UoM 23, 24, 27 and 28). Nine models have been planned in UoM 24. These are shown in Figure 5 and the indicative number of cross sections, structures and 2D model extent are shown in Table 2-C.

Unit of Management 24 Model Group Statistics

Total Number of Total Number of Model ID 2D Area (km 2) Cross Sections Structures S5 186 58 1.81 S6 436 136 21.02 S7 59 7 3.25 S8 295 78 11.73 S9 109 49 0.30 S10 227 58 9.18 S11 274 53 9.24 S12 123 38 5.43 S13 121 13 1.68 Table 2-C Indicative number of cross sections, structures and area of 2D model extent in each of the UoM 24 model groups

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S5 S9

S10 S13

S6

S11

S7

S12 S8

Figure 5 Model Groupings Unit of Management 24

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2.7.2 Constraints, Data Problems and Other Issues

Requests have been made for any hydraulic models in the Unit of Management to be provided. We have not received any existing hydraulic models in the Management Unit and are proceeding on the assumption that there are none available.

2.7.3 Amendments to Methodology

There are no envisaged amendments to the proposed methodology.

2.8 Flood Risk Assessment

The flood risk assessment activity is centred on assessing flood risk for key flood risk receptor groups covering: • Social risk – location and number of residential properties; social infrastructure covering highly vulnerable sites (such as children’s residential homes, homes for the elderly etc.) and high value assets (such as Garda stations, fire stations, hospitals, schools etc.); and social amenity sites (such as parks and leisure facilities). • Risk to the Environment – areas related to integrated pollution prevention and control (IPPC) sites; locations identified under the Water framework Directive; and other environmentally valuable sites such as Special Areas of Conservation (SAC). • Risk to Cultural Heritage – sites of cultural value at risk. • Risk to the Economy – based on type of residential and commercial properties at risk in different magnitude events; transport infrastructure assets (such as roads, railways, ports and airports); utility assets (such as power, water and wastewater, oil and gas facilities etc.).

This will be mapped on a series of Flood Risk Maps

2.8.1 Summary of Work Completed

No work has formally commenced on the Flood Risk Assessment activity, however, the site visits undertaken to date have confirmed the identification of the location of many critical receptors in the four categories identified above. Additionally, as part of the data collection for the Flood Risk Review and Environmental Assessment, much of the data required for this activity has been collected.

2.8.2 Constraints, Data Problems and Other Issues

The data gathered to date has provided significant information to inform each of the four receptor groups outlined above.

For the data not yet obtained and used on activities to date, we do not envisage there being any significant data difficulties. In terms of requesting the data, we would anticipate that the vast majority, if not all, of the data required for this activity will have been requested for other activities and these requests will be made at an appropriate stage in the project to ensure that the latest datasets are used.

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The main data issue in relation to the Flood Risk Assessment is likely to be the provision of up to date data in the Geo-Directory database. We have noted at various locations that there are recently constructed properties that are not shown in the Geo-Directory database. These will need to be included in the overall economic appraisal, and will affect the mapping and analysis related to Social Risk and Risk to the Economy.

2.8.3 Amendments to Methodology

There are no specific amendments to the methodology proposed at tender stage and emphasise that the outputs for this stage will be largely GIS-driven, with receptors grouped into the four principal risk receptor categories, in combination with the flood mapping output from the hydraulic modelling activity.

2.9 Environmental Assessment

There are two distinct environmental assessment processes applicable to the Shannon CFRAM Study: Strategic Environmental Assessment (SEA) and Appropriate Assessment (AA). Both processes will be integral to a number of Study tasks, namely:

• Flood Risk Assessment; • Consultation and Engagement; • Development of Flood Risk Management Options; and • Flood Risk Management Plan preparation.

Strategic Environmental Assessment

The FRMP for this UoM 24 will be subject to a SEA. The SEA process can be defined by four stages, all of which include some level of consultation with stakeholders and the public. We are currently at Stage 2 of the SEA process – Scoping . Figure 6 illustrates the links between the SEA stages and the SEA deliverables associated with the FRMP for UoM 24.

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Figure 6 Stages of the SEA associated with the development of the FRMP

Appropriate Assessment

An AA will be undertaken to identify and address any potential impacts the flood risk management options and the FRMP might have on areas designated as Natura 2000 sites as well as any associated candidate sites.

Work associated with the AA will be undertaken concurrently with the SEA, but both processes will be clearly distinguished and the AA will result in the production of an AA Screening Statement and, if appropriate, a Natura Impact Statement (NIS) for the UoM 24 FRMP. The NIS will establish whether or not a FRMP is likely to have a significant impact on any Natura 2000 site in the context of their conservation objectives and on the habitats and species for which a Natura 2000 site have been designated.

Using the provisional Study programme, Figure 7 illustrates how the Study tasks relate with the outputs of both the SEA and AA processes. It is emphasised that this is a high level programme with the timing of activities shown within 4-month periods, such that the start or end of an activity bar does not indicate the actual start or completion date of that activity.

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Figure 7 Relationship between the Study tasks and Outputs of the SEA and AA processes

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2.9.1 Summary of Work Completed

The following tasks have been completed, covering all Units of Management: • Initial literature review to inform the identification and engagement of SEA / AA related stakeholders; • Identification and register of key stakeholders: o Statutory consultees (Environmental Authorities) for the SEA, namely:
Environmental Protection Agency (EPA);
Department of Communication, Energy and Natural Resources (DCENR) (to include Inland Fisheries Ireland (IFI));
Department of Arts, Heritage and Gaeltacht Affairs (DAHGA) (with regards archaeological, architectural and natural heritage); and
Department of Agriculture, Marine and Food (DAMF) (with regard to marine fisheries). o Primary and Secondary stakeholders. • Strategic Environmental Issues Paper relevant to all UoMs. This document provides an overview of the Shannon CFRAM Study and proposed FRMPs and also summarises initial thoughts on issues relating to flood risk management and the wider environment. This will be used to consult with and engage stakeholders; and • Presentations/meetings with the EPA and IFI as well as tele-communication and written correspondence with other Environmental Authorities and Primary Stakeholders to scope and arrange an Environmental Pre-Scoping Workshop (scheduled for 27 th July 2011).

The following tasks are in progress: • Data collection and detailed literature review to establish the environmental baseline; • Preparation of documentation such as presentations, workshop materials and maps, to facilitate consultation and engagement of key stakeholders; • Development of the Environmental Scoping Report; and • Preparation of environmental training material (as required by Section 2.10 of the Stage 1 Brief).

2.9.2 Constraints, Data Problems and Other Issues

No significant issues have been identified to date. Initial thoughts on the key issues have been outlined in the Environmental Issues Paper, and as the SEA process develops, we will investigate and report further on existing and future environmental characteristics of the Study Area which can influence the risk and repercussions of flooding and constrain or provide opportunities for the implementation of strategic flood risk management options.

Data collection for the SEA and AA has been limited to date as it is considered more appropriate to first seek input from the Environmental Authorities at the Environmental Pre-Scoping Workshop (July 2011). This will help facilitate a more focused, efficient approach to data collection. Also, it is acknowledged that some datasets may become out-dated as the study progresses over its 5-year programme, and guidance from the Environmental Authorities will help establish an effective method of data collection and maintenance.

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2.9.3 Amendments to Methodology

There are no amendments to the methodology outlined in the Stage 1 Brief. The SEA and AA will be undertaken in accordance with Section 9 and Appendix K of the Stage I Brief, and the relevant EU Directives and transposing regulations.

2.10 Consultation and Engagement

The Communications and Engagement activities are relevant to the whole of the Shannon RBD. However, in the sections below, where necessary, specific reference is made to activities related to this Unit of Management within the context of the wider communications and engagement processes.

2.10.1 Summary of Work Completed

A Communications and Engagement Plan has been produced (and reviewed and approved by OPW) which:

• Outlines the approach to be taken in fulfilling the Project Brief (Appendix L) and supporting the communications and engagement objectives; • Presents our team organogram and communications governance roles and responsibilities; and • Presents initial stakeholder identification and mapping, and how we plan to work with stakeholders.

The Communication and Engagement Action Plan and Stakeholder Database are critical components of the ‘live’ Communications and Engagement Plan, and will be updated throughout the life of the project to provide a complete log of stakeholder communications and intelligence, and robust record of engagement activities undertaken and with whom. Maintenance of the Action Plan and Stakeholder Database is ongoing.

We are currently in the second stage of our four phase approach to communications and engagement:

1. Set up and planning (established tools for ongoing communications e.g. newsletters, media relations, website, progress group and advisory group meetings). 2. Engagement (linked to SEA Scoping and FRM Objectives stages) – includes stakeholder workshops and public information and engagement programme. 3. Deliberation (linked to draft Flood Map and Preliminary Options Report stages) – includes stakeholder workshops and public consultation and discussion programme. 4. Feedback (linked to development and publication of draft Flood Risk Management Plans) – includes stakeholder workshops and public feedback programme.

The following communications and engagement activities are currently being carried out or are planned for the SEA Scoping phase over the next 8 months:

• Pre-scoping engagement with statutory consultees (Environmental Authorities) in the form of one-to-one meetings and a one day Pre-Scoping Workshop Part

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1), to gather comments on and develop the Environmental Issues Paper (June / July 2011); • Pre-scoping consultation with primary and secondary stakeholders (in written format) to gather comments on the Environmental Issues Paper and contribute to the draft Environmental Scoping Report (July / August 2011); • Further engagement with Environmental Authorities and primary stakeholders in the form of a one day Scoping Workshop (Part 2 ) (October 2011). • A rolling public consultation programme (including Public Consultation days) (September 2011 – March 2012); and • Statutory public consultation on the final Draft Environmental Scoping Report, in line with legislative requirements (January – March 2012).

Table 2-D shows a list of meetings that have been held with OPW, Local Authorities, and other stakeholders during the early stages of the project (excluding the Progress Group Meetings). These have been primarily to inform the Flood Risk Review and Environmental Assessment related activities. All of these meetings are logged on the Stakeholder Database. Where appropriate, follow up telephone discussions have supplemented these meetings. The meetings which are of specific relevance to this Unit of Management are highlighted in Table 2-D.

Organisation Meeting Location Meeting Date

Office of Public Works Mungret, Co. Limerick 23 rd March 2011 Office of Public Works Mungret, Co. Limerick 9th May 2011 Office of Public Works Mullingar, Co. Westmeath 13 th April 2011 Office of Public Works Headford, Co. Galway 1st June 2011 Office of Public Works Dublin, Co. Dublin 1st June 2011 Project Advisory Group Members Athlone, Co. Westmeath 8th March 2011 Kerry County Council Listowel, Co. Kerry 4th May 2011 Kerry County Council Tralee, Co. Kerry 4th May 2011 Limerick County Council Dooradoyle, Co. Limerick 10 th May 2011 Clare County Council Ennis, Co. Clare 7th June 2011 Roscommon County Council Roscommon, Co. Roscommon 11 th May 2011 Leitrim County Council Carrick on Shannon, Co. Leitrim 19 th May 2011 Galway County Council Ballinasloe, Co. Galway 24 th May 2011 Longford County Council Longford, Co. Longford 25 th May 2011 Westmeath County Council Athlone, Co. Westmeath 31 st May 2011 Offaly County Council Tullamore, Co. Offaly 7th June 2011 North Tipperary County Council Nenagh, Co. Tipperary 10 th June 2011 Electricity Supply Board Dublin, Co. Dublin 29 th March 2011 Waterways Ireland Carrick on Shannon, Co. Leitrim 30 th March 2011 Environmental Protection Agency Dublin, Co. Dublin 2nd June 2011 Inland Fisheries Ireland Athlone, Co. Westmeath 10 th June 2011 Irish Farmers Association Athlone, Co. Westmeath 20th April 2011 Table 2-D Summary of Stakeholder Meetings

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In addition to the planned communications and engagement activities, the Communications and Engagement team are undertaking ongoing correspondence in response to stakeholder and public queries. To date on the Shannon CFRAM study we have received a small amount of correspondence from stakeholder organisations, Teachtaí Dála (TDs), County Councils and interested residents expressing their interest in the Study and asking to be involved as work progresses.

A Communications Protocol has been implemented in the Jacobs Dublin office to ensure that incoming communications from stakeholders and the public are recorded and passed to the correct person in a timely manner, and that all staff are aware of the importance of dealing with phone calls, letters and emails appropriately.

2.10.2 Constraints, Data Problems and Other Issues

The Project Brief requires a total of five workshops to be held over the course of the project; one at each of the five project stages – this constraint in terms of the number of communications and engagement activities that can be undertaken in the process, and the suggested approach for overcoming this constraint, is detailed in section 2.10.3.

The communications and engagement team will be in a position to undertake further more detailed stakeholder identification and mapping as the project progresses and as the project team’s confidence in terms of defined areas of flood risk increases.

Issues may arise where communications with stakeholders and engagement events are not designed and delivered according to the overarching Communications and Engagement Plan. When engagement is ad hoc and reactive, there is the risk that stakeholders become frustrated and disengage from the process altogether. All meetings, presentations, workshops and written communications to stakeholders should adhere to the principles and approach outlined in the Communications and Engagement Plan to ensure a consistent and considered message is given and to reduce the risk of stakeholder fatigue and confusion.

An extra stakeholder meeting was requested by OPW which falls outside of the current scope.

2.10.3 Amendments to Methodology

The Project Brief requires a total of five stakeholder workshops to be held over the course of the project; one at each of the five project stages. However, based on previous experience on similar projects, to be successful and deliver the most benefits the approach to communications and engagement should be:

• Appropriate - it is often not appropriate to involve all stakeholders at the same time during one event. Stakeholders have varying degrees of influence and interest and in order to be useful and cost-effective the engagement process should be designed to inform, engage and provide feedback in the most appropriate ways. A staged approach is often required to ensure that statutory and political stakeholders are engaged before local stakeholder groups and communities – this could mean more than one event per stage is necessary.

• Flexible – as our relationships with stakeholders develops and our knowledge of their priorities and issues grows, we will have a better understanding of how and to what extent they want to be involved. Some stakeholders might want to be

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actively involved in attending (and shaping the format and content of) our engagement events, whereas others might prefer to be kept informed and provided with feedback at the end of the project. We will need to design our communications and engagement programmes around this.

We will need to plan stakeholder and public activities as appropriate at each stage in the context of wider project activity and any influencing political, economic or media related factors at that time; and also, be flexible to stakeholder requests and preferences in light of intelligence gathered and relationships developed.

2.11 Development of Flood Risk Management Options

The development of FRM options at each APSR requires consideration of a range of structural and non-structural options, as different spatial scales of assessment (SSA) as identified in the Project Brief. These need to be integrated with the SEA, and will be developed through consultation process, and tested as necessary through the use of hydraulic modelling. The identification of preferred options also needs to be temporally cohesive – taking account of changing flood risk over time with respect to increased development pressure and climate change impacts.

2.11.1 Summary of Work Completed

No work has been undertaken with specific regard to the developing FRM options. However, the Flood Risk Review activity, in particular the site visits for this task, provided a good insight into the likely flood mechanisms, which has been used to identify potential FRM options.

The Flood Risk Review forms summarise the potential FRM options (for each site visited, these are listed in Section 2.8 of the forms in the Draft Flood Risk Review Report). The purpose of this has been to consider what may be technically feasible, and does not necessarily imply that the options identified are economically viable, or environmentally acceptable. It is also emphasised that no options have been ruled out at this stage.

2.11.2 Constraints, Data Problems and Other Issues

There have been no particular constraints to date with regard to provision of data. However, it is known that at various sites, there is information held by the OPW or by the relevant Local Authority. Typical data includes scheme design drawings, reports on various schemes, scanned drawings of schemes from the 1960s and 1970s (and possibly more recently as well), as built drawings of very recently completed schemes. Some of this data has already been collected, while the location of other information is known.

As the study progresses and the final list of APSRs is confirmed, further specific information from Local Authorities is likely to be required. It is critical for this activity – in relation to valuable data that could inform the development of options – that the Local Authority identifies suitable resources to supply this data in a suitable format for incorporation into the study.

The provision of specific information on known flooding problems and solutions has been of particular value in the early stages of the project, as this enabled the Flood Risk Review to focus on these issues, without losing the strategic view of flood risk within the study area for each location considered (the CARs and AFRRs). This

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information has typically been provided by the OPW regional teams and the Local Authorities, and has demonstrated the value of meeting with these teams as part of the Flood Risk Review process, to inform subsequent stages of the study – such as the development of FRM options.

2.11.3 Amendments to Methodology

There are no specific amendments to the proposed methodology for the development of FRM options. However, the following key points are noted that will inform this activity:

• The preliminary identification of possible options included as part of the Flood Risk Review will inform the High Level Screening Multi-Criteria Analysis, as proposed in the methodology at tender stage.

• In many locations, where there are not a significant number of properties or assets at high risk of flooding, the development of options below the preferred design standard (1%AEP for fluvial flooding and 0.5% AEP for tidal flooding) is likely to provide the highest benefit-cost ratio. These may well take the form of Do Minimum options or maintenance options.

• Small scale capital options are likely to take the form of multiple minor elements grouped together as a composite option, rather than discrete options covering, for example: upstream storage; embankments; walls; diversion channel etc. A typical composite option may comprise: construction of a short length of flood defence wall; increasing the height of a section of embankment; closing a gap in an informal flood defence (e.g. with a flood gate); placing flap valves on unflapped outfalls. These may be supported by development control measures, flood warning and improved maintenance regime.

2.12 Flood Risk Management Plan Preparation

The preparation of the Flood Risk Management Plan is the culmination of all the previous tasks on the project. As such, any data constraints, project risks and opportunities are incorporated within each of those discipline sections (Section 2.3 to 2.11) of this Inception Report.

On the basis of the early work completed on the project to date, at this stage there are no amendments to the proposed methodology for preparing the FRMP.

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3 Data and Data Requirements

3.1 Objectives

The objectives of the data collection exercise, in accordance with the brief, are to search, locate and register all potentially relevant information in the following fields:

• Flood Relief / Risk Management; • Historical Flooding; • Hydrometry; • Meteorology; • Land Uses; • Soils and Geology; • Planning and Development; • Defence and Coastal Protection Assets; • Existing Survey and Geotechnical Information; • Environmental; and • Flood Risk Receptor Information.

Upon receipt of data, the brief requires that the data be reviewed, formatted as necessary, interpreted and made use of.

3.2 Data Collection Methodology

Data collection during the Shannon CFRAM Study Inception Phase has been intensive in order to collect as much relevant data for each technical discipline as possible. Data collection shall however continue throughout the project to ensure that the technical teams utilise as comprehensive and up-to-date information as possible.

The methodology employed in order to obtain relevant data during the Inception Phase is outlined in the following sections. The current Data Register, detailing all information obtained prior to the submission of the Inception Report, is included as Appendix C in accordance with the requirements of Section 2.4.2 Item 2)a) of the Stage I Project Brief.

3.2.1 OPW Datasets

Following the Inception Meeting on the 26 th January 2011, OPW provided a large dataset which comprised the majority of the information that OPW hold in relation to the Shannon River Basin District.

This data was reviewed and logged, and compared to both specific data requirements of the technical teams and the suggested data requirements specified by OPW within the Stage 2 project brief.

3.2.2 External Data Requests

In order to obtain additional data over and above that supplied by OPW, a total of 44 External Data Requests were submitted to relevant organisations. The complete set of External Data Requests is included as Appendix D. A summary of the

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organisations contacted is provided in Table 3-A below. Those organisations contacted with information specifically related to UoM 24 are highlighted.

Organisation Contact Office of Public Works Rosemarie Lawlor John Martin Clare Butler Conor Galvin Peter Newport Joseph McNamara Office of Public Works - Regional Office (East) John G. Murphy Office of Public Works - Regional Office (West) Michael Collins Paul Moroney David Timlin Clare County Council Sean Ward Tom Tiernan Gordon Daly Sharon Corcoran Cork County Council M Riordan Galway County Council Sean Langan Kerry County Council Fergus Dillon John Daly Laois County Council Michael O’Hora Martin Dolan Leitrim County Council Brian Kenny Limerick City Council John O'Shaughnessy Limerick County Council Joe Kennedy Longford County Council Brian Connaire North Tipperary County Council Marie Ryan Offaly County Council David Hogan Roscommmon County Council Majella Hunt Sligo County Council Tom Kilfeather Ray Kenny Westmeath County Council Barry Kenny Border Regional Authority Matt Donnelly Mid West Regional Authority John Bradley Midlands Regional Authority Martin Daly South West Regional Authority John Forde West Regional Authority Teresa O'Reilly National Roads Authority Vincent O'Malley Department of the Environment, Heritage and (1) Seamus Whelan Local Government Caroline Wilkie Coillte Colm O'Kane Marine Institute Guy Westbrook Port Authorities Hugh Conlon Environmental Protection Agency Micheal MacCarthaigh Aidan Murphy Met Eireann Noreen Brennan Electricity Supply Board Brian O'Mahony Waterways Ireland Ray Dunne Table 3-A Summary of Organisations Consulted Notes: (1) At the time of writing, the government department was DoEHLG. This is now split between the Department of Environment, Community and Local Government, and the Department of Arts, Heritage and the Gaeltacht

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3.2.3 Stakeholder Meetings

Stakeholder meetings were held with representatives of OPW, various Local Authorities and other stakeholders, for various purposes, but also to inform the data collection exercise.

A list of meetings that have been held with OPW, Local Authorities, and other stakeholders is provided in Section 2.10.1.

3.2.4 Future Flood Events

A Flood Event Data Collection Procedure has been developed to ensure that any relevant data is collected following any flood events that occur during the life of project. The procedure comprises a desk-based data collection exercise and, where considered both safe and necessary to do so, a site visit.

The procedure details requirements for the collection of the following datasets:

• Flood event location, timing, duration and extents; • Source of the flood event; • Flood water levels and flow data; • Flood mechanisms; • Meteorological data; • Tidal data (where appropriate); • Damage to property and infrastructure; and • Emergency response, including mitigation measures employed.

The procedure may be updated as the study progresses by agreement between OPW and Jacobs.

3.3 Data Review

In accordance with the requirements of the Stage I Project Brief (2.4.2 Items 2)b) and c)), specific data quality and outstanding data issues are summarised for each discipline within Section 2. In addition, summaries of key issues are provided in the following sections.

3.3.1 Data Quality

Descriptions of key data items, their quality and their overall fitness for purpose are provided within each specialist discipline’s section within Section 2 of this report.

A summary of key data quality issues with respect to currently held data is provided as Table 3-B.

For those disciplines not listed in Table 3-B, this indicates that there are no clear current data quality issues.

Further details on hydrology aspects are included in Appendix B (prepared as a separate report).

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Discipline Dataset Remarks (with Data Register reference) Flood Risk An Post Geo- We have noted at various locations that Assessment Directory there are recently constructed properties that are not shown in the Geo-Directory (E-0007 / L-0011) database. These will need to be included in the overall economic appraisal, and will affect the mapping and analysis related to Social Risk and Risk to the Economy. Hydrology Daily flow/level Trends in the available daily mean flow series and level data series were identified at eight out of the twelve gauging stations Instantaneous (24001, 24003, 24005, 24008, 24011, flow/level series 24012, 24013 and 24082). It is possible that these trends may be indicative of external factors or reflect actual trends in the flow and/or level series. Feedback from OPW would be useful to ensure maximum confidence in using the associated flows in future workings. Hydraulic National Digital The supplied NDTM is partially corrupted Analysis Terrain Model and a proportion of the tiles do not open. (J-0002) The data is needed in full by the 30/9/2011 to avoid potential delays to the modelling in some areas, and potential cost implications. This was initially raised by Jacobs in EDR0001 which resulted in OPW resending the NDTM information. Further review has indicated that there are some residual issues remaining which will require a further data request by Jacobs to the OPW. Table 3-B Key Data Quality Issues

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3.3.2 Outstanding Data

Descriptions of any outstanding datasets are provided within each specialist discipline section within Section 2 of this report.

A summary of the implications of these datasets being outstanding with respect to currently held data is provided as Table 3-C.

It should be noted that this is based on data requests made to date and does not imply that the data collection is now complete. As the study progresses, there will be a need to access additional data which will be requested at the time. This may include, for example, environmental or social datasets that are not required now, but will be at some point in the project life cycle. Rather than specifically requesting these data sets now, it is appropriate to wait such that the most up-to-date dataset is provided as and when necessary.

For those disciplines not listed in Table 3-C, this indicates that there are no current outstanding data issues.

3.3.3 Quality, Adequacy, and Interpretation of Data

At this stage, the main data that has been assessed in detail in terms of its adequacy is that relating to the hydrological tasks. Any apparent inadequacies in the data – either in quality or quantity – are specifically addressed in the Preliminary Hydrological Assessment and Method Statement included in Appendix B.

For other tasks, specific concerns have been identified where these are readily apparent from the initial data review.

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Discipline Dataset Date Cost Potential Implications to the Project / Required Implications Proposed Solutions By (€) Environmental All Ongoing None Data collection for the SEA and AA has been limited to Assessment identified to date as it is considered more appropriate to first seek input and Planning date from the Environmental Authorities at the Environmental Pre-Scoping Workshop. This will help facilitate a more focused, efficient approach to data collection. Also, it is acknowledged that some datasets may become out-dated as the study progresses over its 5-year programme, and guidance from the Environmental Authorities will help establish an effective method of data collection and maintenance. Hydrology Daily flow/level 31/8/2011 None Several daily and instantaneous flow and level series for series identified to key hydrometric stations have not been received. date Confirmation of whether the relevant data series exists has Instantaneous been requested in the first instance. flow/level series There is no cost implication associated with the lack of provision of the data below, however, any lack of data may have an impact on the uncertainty and quality of the derived flood flow estimates, hydraulic model calibration and validation and rating reviews, all of which are programmed to be undertaken in the next phases of the project. Hydraulic Existing 31/8/2011 None There will be little impact on the project should no existing Analysis hydraulic models identified to models be available; however, any existing models would date be of use. Any existing models will need to be reviewed and the proposed modelling methodology updated to reflect previous models if appropriate. Table 3-C Outstanding Data

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4 Survey Requirements

4.1 Defence Asset Data

4.1.1 Asset Identification

The Flood Defence Asset Data Collection process involves two stages:

• The broad identification of flood defence assets prior to the defence asset survey being undertaken. • The detailed flood defence asset survey which includes a visual condition inspection and entry into the OPW Flood Defence Asset Database,

This two stage approach has been developed following commencement of the study.

The first stage has been completed and identifies, in broad terms, the type and extent of flood defence assets within each CAR and AFRR within the Unit of Management. The information related to this was gathered during the site visits undertaken as part of the Flood Risk Review. We have concluded that in general the extent of constructed defences is not great.

The second stage has not yet been completed due to the critical nature of the topographic survey as discussed under Section 2.5.

Discussions with OPW through the early stages of the study indicated that because the Defence Asset Survey is not on the critical path, whereas the topographic survey is, then the focus for delivering the survey requirements should be on the topographic survey of the channel and structures to enable the hydraulic model construction to commence as early as possible. It was proposed that subsequently, the surveyors remobilise to undertake the geometric survey of the flood defence assets. Whilst this would incur some minor remobilisation costs for the surveyor, this is outweighed by the much greater risk of the delay in the programme for delivering the topographic survey to enable hydraulic model construction to commence. This approach had been agreed in principle.

Additionally, the requirement to undertake the Defence Asset Survey required in APSRs can only be completed once the identification of all APSRs has been confirmed. This is not due for confirmation until the delivery of the Final Flood Risk Review Report in September 2011.

Prior to undertaking the defence asset survey we will agree the list and location of flood defence assets to be included in the survey with the Advisory Group, as required under Appendix C, Section C1.2 of the Stage I Project Brief.

It is noted that it is a requirement of the topographic survey contracts that flood defences (top of bank etc.) should be surveyed.

4.1.2 Location of Assets Within APSRs

As outlined above, the Defence Asset Survey has not been completed, however, the identification of the asset types within each location has been undertaken. For this Unit of Management, the asset type is given in Table 4-A. This is a provisional list

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and is based on those locations that are recommended in the Draft Flood Risk Review Report to be designated as APSRs.

It is emphasised that the assets identified may include both effective and ineffective flood defences. Based on our knowledge gained from the site visits, many of these assets are ineffective. However, they are listed here because they may form part of a future flood risk management option. For example, a length of flood defence wall that does not tie into high ground may form part of a flood defence “asset” in future, but at present it is ineffective.

It is noted from Table 4-A that there are only five locations that are considered to potentially have a significant number of assets. These are:

• Adare • Clarina • Dromcolliher • Foynes • Newcastle West

All of these locations are marked on the Overview Plan of UoM 24 shown in Section 1.6, Figure 3.

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Flood Defence Related Asset Adare Adare Askeaton Ballylongford Bruree Charleville Clarina Croom Dromcolliher Foynes Kilmallock Milford Newcastle West Rathkeale

Open Channel Watercourses Man-made river channel x Flood relief channel x Canal Mill leat x x Drainage channels / back drains x x x Bridges and Culvert crossings Single Arch bridge x x x x x Multi-Arch bridge x x x x x x x x x x x Single Span bridge x x Multi-Span bridge x x Box culvert(s) x x x x x Pipe culvert(s) x x x x x x x x Arch Culvert(s) x x Culverted Watercourses (culvert length

is greater than a crossing) Box culvert(s) x x x x Pipe culvert(s) x Arch Culvert(s) Irregular Culvert(s) Walls and Embankments Embankment(s) x x(1) x x x x Raised wall(s) x x x x x x x Control Structures -

weirs, gates, dams Fixed crest weir x x Adjustable weir Dam / Barrage Sluice gates Lock gates Radial gates Storage On-line storage (natural) x x x x On-line storage (artificial) x Off-line storage x Outfalls (from main watercourse into

estuary / sea) Flapped outfall(s) into watercourse x x x x x Tidal flap(s) Tidal sluice(s) Other Pumping Station x(2) Erosion Protection Sand Dunes Level of Flood Defence Assets (3) S M M M M S M S S M M S M Table 4-A Potential Flood Defence Assets in UoM 24 Notes: (1) Asset is outside the APSR boundary. (2) Pumps are mobile, and are stored in Limerick. There is no permanent installation. (3) S - Significant assets for potential survey; M - Minor (or no assets for potential survey.

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4.1.3 Location of Assets Outside APSRs

In addition to the assets within the APSR boundaries, the Flood Defence assets noted in Section 2.12 and 2.13 of the Stage II Project Brief are also required to be surveyed. Maps showing the extent of these assets are shown in Figures 8 and 9. For this Unit of Management, it is primarily the assets related to the River Maigue and the River Deel.

Key: CAR 29 – Foynes CAR 50 – Newcastle West CAR 22 – Clarina CAR 3 – Adare

Non-APSR Defence Assets for survey

Figure 8 Assets outside APSR boundaries – UoM 24 east

Key: CAR 9 - Ballylongford

Non-APSR Defence Assets for survey

Figure 9 Assets outside APSR boundaries – UoM 24 west

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4.2 Survey Specification

OPW have reviewed the model contracts to be used for the gauging stations and the Ballylongford APSR. Tender documents will be issued during week beginning July 25 th 2011. These tender document references are as follows:

TD_SURV_0116_V0_0_JAC_TenderDocumentationBallylongford _110719 and TD_SURV_0117_V0_0_JAC_TenderDocumentationGaugingStation_110719

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5 Preliminary Hydrological Assessment and Method Statement

The Preliminary Hydrological Assessment and Method Statement has been prepared as a stand alone report and is included as Appendix B to this Inception Report.

The details included in the report fully reflect the scope of the hydrological elements of the Inception Report as set out in Section 2.4.2, sub-section 4, of the Stage I Project Brief as follows:

a) A preliminary hydrological assessment, including a review of historical floods, catchment boundaries and hydrometric and meteorological data as defined in Sections 6.2, 6.3 and 6.4 (but not including Section 6.4.3).

b) Discussion of historical flood events, including the dates they occurred, their duration, mechanisms, depths, impacts (e.g. number of properties flooded, infrastructure affected, etc.), severity (e.g. flows, levels, estimated annual exceedance probability), etc.

c) A preliminary assessment of past floods and flooding mechanisms.

d) A detailed method statement, setting out the datasets to be used and the approaches to be followed for the hydrometric review as defined in Section 6.4.3, and statistical analysis of data for the estimation of design flows (Section 6.5) for all hydrometric stations (Final reporting of all aspects of the hydrological analysis shall be reported upon in the Hydrology and Hydraulics Report).

The requirements set out in sections 6.2, 6.3 and 6.4 (excluding 6.4.3) specifically cover:

• Review and Analysis of Historic Floods • Catchment Boundaries • Analysis of Hydrometric and Meteorological Data (Rainfall Data and a Hydrometric Data Review)

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6 Inception Phase Conclusions and Summary

The Inception Phase of the Shannon CFRAM study has involved significant activity on several project tasks, applying across all Units of Management, in particular the following:

• Data Collection (Section 3, Stage I Project Brief) • Flood Risk Review (Section 4, Stage I Project Brief) • Surveys (Section 5, Stage I Project Brief) • Hydrological Analysis (Section 6, Stage I Project Brief) • Hydraulic Analysis (Section 7, Stage I Project Brief) • Environmental Assessment (Section 9, Stage I Project Brief) • Consultation and Engagement (Section 10, Stage I Project Brief)

This report provides summary status of all project activities undertaken to date, but with a particular focus on three aspects:

• Data and Data requirements • Survey Requirements • Preliminary Hydrological Assessment and Method Statement

The main conclusions and summary points for each activity are as follows:

Data Collection • An extensive data collection exercise has been undertaken, including requests to OPW, Local Authorities and a range of other stakeholders. • There are some data quality issues related to future activities on Flood Risk Assessment, Hydrological Analysis and Hydraulic Analysis. • There are some outstanding data issues related to Environmental Assessment, Hydrological Analysis and Hydraulic Analysis. • Data collection will be ongoing and will evolve as the project develops as it becomes apparent that further data is required. • A Flood Event Data Collection Procedure is being developed to ensure that any relevant data is collected following any flood events that occur during the life of project. • A Data Register and a Register of External Data Requests has been developed.

Flood Risk Review • The Draft Flood Risk Review Report has been issued to OPW and the Local Authorities for comment. • For UoM 24, 12 CARs and six AFRRs have been assessed resulting in the (draft) recommendation that 13 of these sites should be designated as APSRs. • There is an outstanding issue with regard to the possible addition of further sites to be considered as AFRRs, to be resolved in August 2011.

Surveys • The specifications and contract documents for the topographic surveys for the APSRs, and the gauging stations requiring a rating review are in preparation, covering UoMs 23, 24, 27 and 28. • Asset survey requirements are in preparation, with a preliminary indication of flood defence related assets having been identified from site visits.

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• For UoM 24, there are only five locations that are considered to potentially have a significant number of assets. These are:  Adare  Clarina  Dromcolliher  Foynes  Newcastle West

Hydrological Analysis • The preliminary hydrological assessment for UoM 24 has been completed (details given in Appendix B). This covers a detailed review of historical floods, catchment boundaries, hydrometric data and meteorological data. • There are some outstanding data issues with regard to provision of flow data.

Hydraulic Analysis • No hydraulic analysis in terms of hydraulic modelling has been undertaken. However, the reaches to be modelled, and how this is broken down into specific model reaches has been defined for UoM 24. • There are a total of nine models proposed for UoM 24, with around 1700 cross- sections and 500 structures to be surveyed. • There are important considerations in terms of cost savings on topographic survey, and appropriate modelling of watercourses related to the identification (or not) of watercourses on the EPA Blue Line network. This issue was highlighted during the Flood Risk Review.

Environmental Assessment • A register of key environmental stakeholders has been developed including statutory consultees, and primary and secondary stakeholders. • The Strategic Environmental Issues Paper relevant to all UoMs has been issued. This will be used to consult with and engage stakeholders. • Presentations and meetings have been held with the EPA and IFI, and the Environmental Pre-Scoping Workshop has been held.

Consultation and Engagement • A Communications and Engagement Plan has been produced and approved. • A wide range of meetings have been held with OPW, Local Authorities, and other stakeholders during the early stages of the project, primarily to inform the Flood Risk Review and Environmental Assessment related activities. These have proved to be invaluable as a source of information and to engage in the project. • There is a need to remain flexible in the consultation and engagement processes, in terms of the format, content, and stakeholder presence. This may warrant more (or different) events to those prescribed in the Project Brief.

Other project activities that have not commenced yet are Flood Risk Assessment , Development of Flood Risk Management Options, and Preparation of Flood Risk Management Plans.

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Appendix A Extracts from the Project Brief

Extract from Section 2.4.2 of the Stage I Project Brief (June 2010)

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Appendix B Preliminary Hydrological Assessment and Method Statement

The Preliminary Hydrological Assessment and Method Statement is provided as a separate document, reference;

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.pdf

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Appendix C Data Register

The Data Register is provided in spreadsheet form;

Appendix C - Data register 110726.xls

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Appendix D External Data Requests

The External Data Requests Register is provided in spreadsheet form;

Appendix D - Data Requests 110726.xls

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Shannon Catchment-based Flood Risk Assessment and Management (CFRAM) Study

Inception Report – Unit of Management 24

Final Report Appendix B: Preliminary Hydrological Assessment and Method Statement

4 July 2012

Document control sheet BPP 04 F8

Client: Office of Public Works Project: Shannon CFRAM Study Job No: 32103000 Document Title: Preliminary Hydrological Assessment and Method Statement – UoM 24

Originator Checked by Reviewed by Approved by

DRAFT NAME NAME NAME NAME Helen Harfoot Steve Dunthorne Steve Dunthorne Mike Hind DATE SIGNATURE SIGNATURE SIGNATURE SIGNATURE 21st July 2011

Document Status: Issued as part of Draft Inception Report

REVISION NAME NAME NAME NAME V0_A Helen Harfoot Iain Blackwell Iain Blackwell Peter Smyth DATE SIGNATURE SIGNATURE SIGNATURE SIGNATURE 16th Jan 2012

Document Status: Issued as part of Draft Final Inception Report

REVISION NAME NAME NAME NAME Steve Dunthorne/ Steve Dunthorne/ Elmar Torenga Peter Smyth V1_0 Iain Blackwell Iain Blackwell DATE SIGNATURE SIGNATURE (PP) SIGNATURE (PP) SIGNATURE 4th July 2012

Document Status Issued as part of Final Inception Report

Copyright Copyright Office of Public Works. All rights reserved.

No part of this report may be copied or reproduced by any means without prior written permission from the Office of Public Works. If you have received this report in error, please destroy all copies in your possession or control and notify the Office of Public Works.

Legal Disclaimer This report is subject to the limitations and warranties contained in the contract between the commissioning party (Office of Public Works) and Jacobs Engineering Ireland Limited.

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Contents

1 Background 1

1.1 Background 1

1.2 Preliminary hydrological assessment and method statement 1

2 Study Area 3

2.1 Introduction 3

2.2 Shannon River Basin District 3

2.3 Units of management 3

2.4 Shannon Estuary South (Unit of Management 24) 4 2.4.1 Communities at Risk 8 2.4.2 Individual Risk Receptors 8

3 Hydro-meteorological data availability 9

3.1 Introduction 9

3.2 Data requirements 9

3.3 Hydrometric network in relation to CARs and IRRs 11

3.4 Rainfall data 14 3.4.1 Background 14 3.4.2 Daily rainfall data 14 3.4.3 Sub-daily rainfall data 15

3.5 Hydrometric data 17 3.5.1 Background 17 3.5.2 Instantaneous flow and level data 18 3.5.3 Daily mean flow or level data 18 3.5.4 OPW quality codes 22 3.5.5 Annual maximum flow and level data 23 3.5.6 Hydrometric station rating reviews 23 3.5.7 Check gaugings 26 3.5.8 Gauging station visits 26

3.6 Coastal data 26

3.7 Flood Studies Update 26 3.7.1 Work Package 1.2 – Estimation of point rainfall frequencies 27 3.7.2 Work Package 2.1 – Flood flow rating review 27 3.7.3 Work Package 2.2 – Flood frequency analysis 30 3.7.4 Work Package 3.2 – Hydrograph width analysis 30

3.8 Historical flood events 30

3.9 Outstanding data and recommendations 30 TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc FINAL

4 Hydrological Estimation Points 31

4.1 Introduction 31

4.2 Methodology 31

4.3 Lessons Learned 32

4.4 Conclusions 32

4.5 Recommendations and Way Forward 32

5 Catchment Boundaries 33

5.1 Introduction 33

5.2 Data 33

5.3 Methodology 34

5.4 Results of analysis 34 5.4.1 Discrepancy Area 24-1 – Dunvullen (Doonvullen) 36 5.4.2 Discrepancy Area 24-2 – Galbally 37 5.4.3 Random check 38

5.5 Conclusions 39

5.6 Recommendations 40

5.7 Way forward 40

6 Review of Meteorological Data 41

6.1 Introduction 41

6.2 Distribution of raingauges within Shannon Estuary South 41

6.3 Data review 41

6.4 Raingauge selection 42

6.5 Rainfall probability plots 43

6.6 Events of interest 43 6.6.1 Event of 11 - 12 October 1988 44 6.6.2 Event of 29 - 30 December 1998 45 6.6.3 Event of 6 - 7 November 2000 46 6.6.4 Event of 31 July – 1 August 2008 47 6.6.5 Event of 31 January - 1 February 2009 48

6.7 Flood Studies Update rainfall comparison 49

6.8 Conclusions 51

7 Review of Fluvial Data 52

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7.1 Introduction 52

7.2 Distribution of flow and level gauging stations within UoM 24 52

7.3 Data review 55

7.4 Annual maxima flow and level series 57

7.5 Flow and level flood frequency curves 60

7.6 Event analysis 60

7.7 Maigue catchment 61 7.7.1 Event of 29 - 30 December 1998 61 7.7.2 Event of 6 - 7 November 2000 62 7.7.3 Event of 6 - 7 November 2000 63 7.7.4 Event of 31 January - 1 February 2009 64 7.7.5 Maigue catchment discussion 67

7.8 Deel catchment 69 7.8.1 Events of 11 – 12 and 21 – 22 October 1988 69 7.8.2 Event of 29 - 30 December 1998 70 7.8.3 Event of 31 July – 1 August 2008 72 7.8.4 Deel catchment discussion 75

7.9 Other catchments 77

7.10 Conclusions 77

8 Historical Flood Risk Review 78

8.1 Introduction 78

8.2 Records of historical flood risk 79

8.3 Maigue catchment 79 8.3.1 Records of historical flood risk 79 8.3.2 Discussion 80

8.4 Deel catchment 81 8.4.1 Records of historical flood risk 82 8.4.2 Discussion 83

8.5 Other catchments 85 8.5.1 Records of historical flood risk 85 8.5.2 Discussion 86

8.6 IRR 1 Tarbert Power Station 86

9 Proposed Methodologies for Future Work 87

9.1 Introduction 87

9.2 Hydrometric gauging station rating reviews 87 9.2.1 Data required 87 9.2.2 Methodology 87 TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc FINAL

9.3 Design events 88 9.3.1 Data required 88 9.3.2 Methodology 88 9.3.3 Output 91 9.3.4 Application to hydraulic models 91

9.4 Joint probability 94

9.5 Hydraulic model calibration 94

9.6 Coastal modelling 94 9.6.1 Tide and surge 94 9.6.2 Wave overtopping 95

10 Constraints, Data Problems and Other Issues 98

11 Conclusions 99

12 References 101

Appendix A - All hydrometric stations listed in EPA register Appendix B - Double mass rainfall plots Appendix C - 1-day and 4-day rainfall probability plots Appendix D - FSU depth duration frequency plots Appendix E - Daily mean flow review Appendix F - Flood frequency probability plots Appendix G - Catchment boundary discrepancies Appendix H - Gauging station summary sheets Appendix I - Historical flood risk review details

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List of tables

Table 2-A Communities at Risk in Shannon Estuary South (UoM 24) 8 Table 2-B Individual Risk Receptors in Shannon Estuary South 8 Table 3-A Key hydrometric stations identified for Shannon Estuary South (grey boxes indicate no data available) 11 Table 3-B Daily rainfall data available within Shannon Estuary South 15 Table 3-C Instantaneous flow and level data available within UoM 24 and their period of record 20 Table 3-D Daily mean flow and level data available within UoM 24 and their period of record (Grey boxes indicate no data available) 21 Table 3-E OPW quality codes and corresponding Jacobs classification 22 Table 3-F Annual maximum flow and level data for hydrometric gauges located within UoM 24 (NB: FSU AMAX flow series only listed if AMAX flow series was not available from the OPW) 23 Table 3-G Summary of gauging station rating reviews required and rating equations and check gaugings provided. 24 Table 3-H FSU gauging station classification (from Hydrologic, 2006) 27 Table 3-I Number of stations suitable for flood flow analysis classified A1, A2 or B 28 Table 3-J Summary of FSU Rating Classification for hydrometric stations within UoM 24. 29 Table 5-A Catchment boundary and topographical data available for Shannon CFRAM study 33 Table 6-A Summary of rainfall data, period of record and missing days 41 Table 6-B Cumulative rainfall for stations in Shannon Estuary South between 1 January 2001 and 29 March 2004. 42 Table 6-C Maximum rainfall depths for 1 day, 2 day, 4 day and 10 day durations with corresponding AEP for 1 day and 4 day durations (October 1988) 45 Table 6-D Maximum rainfall depths for 1 day, 2 day, 4 day and 10 day durations with corresponding AEP for 1 day and 4 day durations (December 1998) 46 Table 6-E Maximum rainfall depths for 1 day, 2 day, 4 day and 10 day durations with corresponding AEP for 1 day and 4 day durations (November 2000) 47 Table 6-F Maximum rainfall depths for 1 day, 2 day, 4 day and 10 day durations with corresponding AEP for 1 day and 4 day durations (August 2008) 48 Table 6-G Maximum rainfall depths for 1 day, 2 day, 4 day and 10 day durations with corresponding AEP for 1 day and 4 day durations (January 2009) 49 Table 6-H Rainfall depths for a range of frequencies and two durations obtained from grids corresponding to the locations of raingauges 4811, 4911 and 5111. 49 Table 6-I 1 day and 4 day rainfall and associated Annual Exceedance Probability (AEP) for raingauge 4611 50 Table 6-J 1 day and 4 day rainfall and associated Annual Exceedance Probability (AEP) for raingauge 4811 50 Table 6-K 1 day and 4 day rainfall and associated Annual Exceedance Probability (AEP) for raingauge 5111 50 Table 7-A Summary of daily mean flow and level data review (see also Appendix E) (grey squares indicate no data) 56 Table 7-B Top 5 (A) and Top 6-10 (B) AMAX flow or level for hydrometric gauging stations within UoM 24. 59 TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc FINAL

Table 7-C Summary of timings and flows for the flood event 29 - 30 December 1998 61 Table 7-D Estimated annual exceedance probabilities for peak flows during December 1998 event 62 Table 7-E Summary of timings and flows for the flood event 6 – 7 November 62 Table 7-F Summary of timings and flows for the flood event 6 – 7 November 63 Table 7-G Estimated annual exceedance probabilities for peak flows during November 2000 event 64 Table 7-H Summary of timings and flows for the flood event 31 January – 1 February 2009 64 Table 7-I Estimated annual exceedance probabilities for peak flows during January 2009 event 65 Table 7-J Peak flow, volume of flow and runoff for 3 events in the Maigue catchment. 68 Table 7-K Summary of timings and flows for the flood event 11 – 12 October 1988 69 Table 7-L Estimated Annual Exceedance Probabilities for peak flows in the Deel catchment during October 1988 event 70 Table 7-M Summary of timings and flows for the flood event 29 – 30 December 1998 71 Table 7-N Estimated annual exceedance probabilities for peak flows in the Deel catchment during the December 1998 event 72 Table 7-O Summary of timings and flows for the flood event 31 July – 1 August 2008 72 Table 7-P Estimated annual exceedance probabilities for peak flows in the Deel catchment during the August 2008 event 73 Table 7-Q Peak flow, volume of flow and runoff for 3 events in the Deel catchment 76 Table 8-A Quality codes assigned to data in floodmaps (OPW) 78 Table 8-B Summary of historical flood events in CARs within the Maigue catchment 80 Table 10-A Outstanding hydrometric data for Shannon Estuary South (UoM 24) 98

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List of figures

Figure 1 Shannon River Basin District and the five units of management 6 Figure 2 Shannon Estuary South Unit of Management (UoM 24) 7 Figure 3 Location of hydrometric gauging stations in relation to Communities at Risk and Individual Risk Receptors within Shannon Estuary South 13 Figure 4 Location of daily raingauges within Shannon Estuary South 16 Figure 5 Location of hydrometric gauging stations within Shannon Estuary South Unit of Management 19 Figure 6 Hydrometric gauging stations within Shannon Estuary South requiring a rating review 25 Figure 7 Catchment Boundaries Overview 35 Figure 8 Discrepancy Area 24-1 (Dunvullen) 37 Figure 9 Discrepancy Area 24-2 (Galbally) 38 Figure 10 Random Check Area UoM 24 (Dromcolliher, FSU catchment 24- 1483-5) 39 Figure 11 Daily rainfall – 3rd October to 12th October 2011 (NB: rainfall missing at 4611 on 8th October 1988) 44 Figure 12 Daily rainfall – 21st December to 30th December 1998 45 Figure 13 Daily rainfall – 28th October 6th November 2000 46 Figure 14 Daily rainfall – 24th July to 2nd August 2008 47 Figure 15 Daily rainfall – 22nd January to 31st January 2009 48 Figure 16 Shannon Estuary South Unit of Management with the Maigue, Deel and Other sub-catchments delineated 54 Figure 17 Hydrographs for the three events on the River Maigue 66 Figure 18 Hydrographs for gauging station in the Deel catchment for: 74 Figure 19 Typical model hydrograph method 93 Figure 20 Tide/Surge Hydrograph 95 Figure 21 (a and b) Wave overtopping hydrograph 97

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Glossary

AEP Annual Exceedance Probability (expressed as a percentage) APMR Areas of Potential Moderate Risk APSR Areas of Potential Significant Risk CFRAM Catchment Flood Risk Assessment and Management DAD Defence Asset Database DAS Defence Asset Survey DoEHLG Department of Environment, Heritage and Local Government DEM Digital Elevation Model (Includes surfaces of structures, vegetation, etc.) DTM Digital Terrain Model (often referred to as ‘Bare Earth Model’) EPA Environmental Protection Agency FRMP Flood Risk Management Plan HEFS High-End Future Scenario HPW High Priority Watercourses IRR Individual Risk Receptors MPW Medium Priority Watercourses MRFS Mid-Range Future Scenario NTCG National Technical Coordination Group PFRA Preliminary Flood Risk Assessment RBD River Basin District UoM Unit of Management WFD Water Framework Directive

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1 Background

1.1 Background

The Shannon Catchment-based Flood Risk Assessment and Management (CFRAM) Study forms part of the National Flood Risk Assessment and Management Programme.

As part of the Shannon CFRAM Study, there is the requirement to complete a series of Inception Reports, one covering each unit of management within the Shannon River Basin District (RBD).

A major requirement of the Inception Report is to report on the hydrological aspects of the study. The work undertaken for the hydrological analysis to date will form the basis of a significant part of the Hydrological Report, scheduled for delivery in 2012. The hydrological aspects of the Inception Report are reported in this Preliminary Hydrological Assessment and Method Statement.

1.2 Preliminary hydrological assessment and method statement

This report fulfils the requirements of the preliminary hydrological assessment and method statement within the Inception Report, as set out under Section 2.4.2, Item (4) in the Stage I Project Brief:

a) A preliminary hydrological assessment, including a review of historical floods, catchment boundaries and hydrometric and meteorological data as defined in Sections 6.2, 6.3 and 6.4 (but not including Section 6.4.3).

b) Discussion of historical flood events, including the dates they occurred, their duration, mechanisms, depths, impacts (e.g., number of properties flooded, infrastructure affected, etc.), severity (e.g., flows, levels, estimated annual exceedance probability), etc.

c) A preliminary assessment of past floods and flooding mechanisms.

d) A detailed method statement, setting out the datasets to be used and the approaches to be followed for the hydrometric review as defined in Section 6.4.3, and statistical analysis of data for the estimation of design flows (Section 6.5) for all hydrometric stations (Final reporting of all aspects of the hydrological analysis shall be reported upon in the Hydrology and Hydraulics Report).

The requirements set out in sections 6.2, 6.3 and 6.4 (excluding 6.4.3) as referred to in a) above, are outlined below:

6.2. REVIEW AND ANALYSIS OF HISTORIC FLOODS The Consultant shall analyse all available previous studies and reports and the historic flood data collected (see Sections 3 and 4) in terms of peak levels, flood extents, damage caused, flows, etc. Such data shall be utilised in the analysis described below. The Consultant shall also rank the historic flood events in the APSRs and, for fluvial flood events, within each catchment within the Study Area, in terms of magnitude, including those for which only outline information is available, and estimate annual exceedance probabilities for all such events using TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc FINAL 1 of 100

appropriate statistical methodologies. The Consultant shall use the peak levels and flood extents, including anecdotal information from informed individuals, recorded or observed during historical flood events, as references for comparison with design flood levels (developed as per Section 6.5, 7.2 and 7.2) and flood extents (developed as per Section 7.5) to ensure consistency between observed events and design events, particularly with reference to the estimated annual exceedance probabilities of those events.

6.3. CATCHMENT BOUNDARIES The Consultant shall, following necessary hydrological analysis, establish the catchment boundaries and sub-catchment boundaries for each of the Hydrological Estimation Points (see Section 6.5.3), and provide details of same to the OPW in compliance with GIS and hard copy format requirements for this project. The catchment boundaries defined for the purposes of the implementation of the Water Framework Directive will be provided to the Consultant to facilitate, and form the basis of this process, but the Consultant shall review and confirm these boundaries and, with the assistance of the OPW and, where relevant, through cooperation with consultants undertaking other CFRAM Studies, resolve any discrepancies arising.

6.4. ANALYSIS OF HYDROMETRIC AND METEOROLOGICAL DATA 6.4.1. Rainfall Data The Consultant shall, promptly upon receipt, analyse historic and recorded rainfall data throughout the catchment in terms of severe rainfall event depths, intensities, durations, etc., and shall estimate probabilities for significant and / or recent events, with reference and comparison made to the Flood Studies Update data and other relevant research. The OPW shall provide the Consultant upon appointment with the rainfall depth- duration frequency data as generated by Met. Éireann for the Flood Studies Update. This data, available in GIS format, provide national coverage of depth- duration-frequency data for 2km grid squares.

6.4.2. Hydrometric Data Review The Consultant shall promptly upon receipt analyse the historic and recorded water levels, including tidal and surge levels and estimated flows (with due reference given to the rating reviews – Section 6.4.3), in terms of peak flood levels and flows, hydrograph shape, flood volumes, etc. and shall estimate probabilities for major or recent events, with reference and comparison made to the Flood Studies Report and / or other relevant research.

The hydrological work for the Inception report has focused on the Communities at Risk (CARs) and Individual Risk Receptors (IRRs) identified in Technical Note 007 (17th March). The CARs and IRRs form the basic Areas of Potential Significant Risk (APSR) to which will be added the additional areas identified in the Flood Risk Review to form the final list of APSRs. The Flood Risk Review has been undertaken in parallel with this hydrological work.

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2 Study Area

2.1 Introduction

The boundary of the Shannon CFRAM study area is delineated by the Shannon River Basin District (RBD) as defined for the Water Framework Directive. The Shannon RBD is designated an international RBD as a consequence of a small portion of the Shannon headwaters lying within County Fermanagh, Northern Ireland. No particular flood risk areas were identified in the Northern Irish portion, and this study will focus on the Shannon RBD within the Republic of Ireland.

2.2 Shannon River Basin District

The Shannon River Basin District is the largest River Basin District (RBD) in Ireland, 2 covering approximately 17,800 km and more then 20% of the island of Ireland. The Shannon RBD is an International RBD. The RBD includes the entire catchment of the River Shannon and its estuary as well as some catchments in North Kerry and West Clare that discharge to the Atlantic (ref. Figure 1).

The Shannon River rises in the Cuilcagh Mountains, at a location known as the Shannon Pot in the counties of Cavan and Fermanagh (in Northern Ireland). The river flows in a southerly direction before turning west and discharging through the Shannon Estuary to the Atlantic Ocean between counties Clare and Limerick. While the River Shannon is 260km long from its source to the Shannon Estuary in Limerick City, over its course the river falls less then 200m. Significant tributaries of the Shannon include the Inny, Suck and Brosna. There are several lakes in the RBD, including Lough Ree, Lough Derg and Lough Allen. Several of these lakes are on the River Shannon.

The RBD includes parts of 17 counties: Limerick, Clare, Tipperary, Offaly, Westmeath, Longford, Roscommon, Kerry, Galway, Leitrim, Cavan, Sligo, Mayo, Cork, Laois, Meath and Fermanagh. The population of the RBD is approximately 670,000 (based on CSO census data 2006). While much of the settlement in the RBD is rural there are five significant urban centres within the RBD: Limerick City (90,800), Ennis (24,300), Tralee (22,700), Mullingar (18,400), Athlone (17,500) and Tullamore (12,900). Agriculture is the primary land use in the district, using 70% of the land, and this is reflected in the district’s settlement patterns.

2.3 Units of management

Units of management, as developed by the OPW, constitute major catchments / river basins (typically greater than 1000km2) or conglomerations of smaller river basins and their associated coastal areas.

There are five units of management within the Shannon River Basin District (ref. Figure 1):

• Unit of Management 23 Tralee Bay – Feale • Unit of Management 24 Shannon Estuary South • Unit of Management 25/26 Shannon Lower and Upper • Unit of Management 27 Shannon Estuary North • Unit of Management 28 Mal Bay

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This report appraises the Shannon Estuary South Unit of Management (UoM 24) only. Analysis and discussion for the remaining units of management will be presented in separate reports.

2.4 Shannon Estuary South (Unit of Management 24)

The Shannon Estuary South Unit of Management (or UoM 24) is shown in its wider context within the Shannon RBD in Figure 1, and in more detail in Figure 2. It encompasses areas of four counties; Kerry, Limerick, Cork and Tipperary. It consists of a fertile limestone plain, known as the ‘Golden Vale’ bounded on the north by the Shannon Estuary and on the west and south and east by the Mullaghareirk Mountains, Ballyhoura Mountains, Galty Mountains and Slieve Felim Mountains. The total area of UoM 24 is approximately 2000 km2.

The unit of management is dominated by two main river catchments, the Deel and the Maigue, which together cover 65% of the unit of management. The coastline extends along the Shannon Estuary from Limerick City in the east to where it meets the Atlantic Ocean between Loop Head (County Clare) and Kerry Head (County Kerry), west of this unit of management.

The River Deel rises in the Mullaghareirk Mountains near Dromina. It flows roughly in a north-westerly direction though the mountains, where it is joined by numerous tributaries, including the Finglasha River and the Ahavarragh Stream which drains the lands upstream of Dromcolliher. Downsteam of Newcastle West, the River Deel is joined by the rivers Arra, Dooally and Daar, which drain the steep topography of the Knockanimpaha Mountains which bound the west of the catchment. Downstream of the confluence the River Deel flows north east, through agricultural plains and roughly follows the direction of the N21 towards and through the centre of Rathkeale. Flowing north from Rathkeale the Deel flows through Askeaton, and on to the Shannon Estuary. Where the River Deel enters the Shannon Estuary, the catchment area is approximately 486.1 km2.

The Deel catchment drainage scheme was completed in 1968 and focused on improved drainage for agricultural purposes. Arterial Drainage schemes have historically been undertaken at various locations within the Maigue and Deel catchments for agricultural purposes.

East of the Deel catchment, and bounded to the south by the River Blackwater catchment, lies the Maigue catchment. The River Maigue drains an area of approximately 806 km2, from its source in the Ballyhoura Mountains (County Cork) to where it enters the Shannon Estuary approximately 10km north of Adare.

Rising north of Milford in north Cork, the River Maigue flows east to join the River Loobagh approximately 3km north of Charleville, and then flows north through Bruree. Just downstream of Bruree, the Maigue is joined by the significant tributary of the Morningstar River, which drains a catchment area of approximately 131.9 km2. Continuing northwards, just upstream of Croom, the Maigue is joined by the third significant tributary of the River Camogue. From Croom, the River Maigue flows north-west towards Adare where the River Maigue becomes tidally influenced.

To assist with analysis of data, the unit of management has been divided into sub- catchments consisting primarily of the Maigue catchment to Adare Quay, the Deel catchment to Askeaton and all outstanding catchments classified as ‘Other’. In accordance with the scope, the Ballinacura catchment, which includes Limerick, has

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been included within the Shannon Upper and Lower Unit of Management. Tidal gauges have been analysed separately.

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Figure 1 Shannon River Basin District and the five units of management

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Figure 2 Shannon Estuary South Unit of Management (UoM 24)

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2.4.1 Communities at Risk

Table 2-A outlines the communities identified by OPW as at risk of fluvial and/or tidal flooding. The locations of the Communities at Risk (CARs) are shown in Figure 3.

No. Location Easting Northing Catchment At risk of At risk of fluvial tidal flooding flooding CAR3 Adare 146500 146750 Maigue Yes Yes CAR4 Askeaton 134000 150000 Deel Yes No CAR9 Ballylongford 99500 144750 Other Yes Yes CAR20 Charleville 152250 122500 Maigue Yes No CAR22 Clarina 150000 154000 Other Yes Yes CAR24 Croom 151000 141500 Maigue Yes No CAR25 Dromcolliher 138231 121197 Deel Yes No CAR29 Foynes 125000 151500 Other Yes Yes CAR32 Kildimo New 145250 152750 Maigue Yes Yes CAR35 Kilmallock 161126 127573 Maigue Yes No Newcastle CAR44 129750 133000 Deel Yes No West CAR50 Rathkeale 136750 140750 Deel Yes No

Table 2-A Communities at Risk in Shannon Estuary South (UoM 24)

2.4.2 Individual Risk Receptors

A number of assets within the Shannon RBD have been identified as Individual Risk Receptors (IRRs). These assets located outside of an Area of Potential Significant Risk and if flooded, would give rise to significant detrimental impact or damage.

One individual risk receptor (IRR) is located within the Shannon Estuary South as shown in Table 2-B and Figure 3.

No. Location Easting Northing Catchment At risk of At risk of fluvial tidal flooding flooding IRR1 Tarbert Power 107750 149250 Other No Yes Station Table 2-B Individual Risk Receptors in Shannon Estuary South

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3 Hydro-meteorological data availability

3.1 Introduction

Within the Shannon River Basin District the hydro-meteorological network is owned and operated by various government and private organisations. These include:

• Office of Public Works (OPW); • Environmental Protection Agency (EPA); • Waterways Ireland; • Electricity Supply Board (ESB); • Met Éireann; • Local Councils; • Bord Na Mona.

Hydro-meteorological data is collated, quality assured and distributed primarily by the following organisations:

• river and lake levels and flows by the OPW, the EPA (on behalf of Local Councils), Waterways Ireland and ESB; • rainfall data by Met Éireann • tidal data by the OPW

Historically, organisations have collected data in accordance with their own requirements. This historical requirement is important to bear in mind when considering the appropriateness of flow data, for example if low flows were the target of monitoring, the location may be inappropriate for high flow assessment.

Since the introduction of the Arterial Drainage Act 1945, the OPW has collected flow and level data, with an emphasis on high flows, to monitor the impact of drainage schemes.

A national programme of hydrological data collection is coordinated by the EPA in accordance with the Environmental Protection Act 1992. However, there is not currently any single organisation responsible for collecting flood peak data, although in a recent strategic review the recommendation was made that this responsibility should be given to the OPW (JBA, 2008). The following organisations have a role with regard to the collection of flood peak data:

• Office of Public Works • Environmental Protection Agency • Waterways Ireland • Electricity Supply Board

Organisations listed above were all approached for data during the data collection phase of the Shannon CFRAM study.

3.2 Data requirements

The following hydro-meteorological data sets were identified as essential for the Shannon CFRAM Study hydrological assessment:

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• Instantaneous (15 minute or digitised chart logger) river and lake level, flow and tidal data; • Daily mean river and lake level, flow and tidal data; • Rating equations and reviews for hydrometric sites; • Check gaugings (also referred to as spot flow gaugings); • Annual Maximum (AMAX) flow and level series; • Daily and sub-daily rainfall; • Soil Moisture Deficit (SMD); • All Flood Studies Update (FSU) reports and worksheets.

The EPA hydrometric register (dated January 2011) lists 59 river and lake level, flow and tidal level gauging stations within UoM 24 (Appendix A), of which only 31 locations are currently active. A further two OPW operated gauging stations, 24093 and 24094, not included on the EPA register were identified via an OPW GIS layer.

Within this preliminary data collection phase, all efforts were made to obtain a full record of all available hydrometric data within UoM 24. Various hydrometric data sets were provided by the OPW at the start of the Shannon CFRAM Study. When incomplete data sets were identified and it was not possible to obtain all records, ‘key’ hydrometric stations were identified to ensure that sufficient data was obtained to fulfil our requirements for the study. Key stations were identified based on the following criteria:

• Proximity to Communities at Risk or Individual Risk Receptors; • Whether a rating review was required (ref. Table 3-A); • Whether a hydrometric station improved the spatial distribution of data throughout the UoM and sub-catchments (ref. Table 3-A).

Where appropriate, short records, inactive stations or staff gauge only sites were included in the list on the basis that even minimal data may provide some information on peak flows or flow characteristics in the absence of any other information.

At this stage all gauges within the UoM have been considered, and the key stations of Table 3-A were selected on the basis that they are likely to be of greatest value based on the criteria listed above. However, it is conceivable that in subsequent stages of the study, data from other gauging stations may prove to be useful. Exclusion of a gauge at this stage does not imply that it would not be considered further. This may include, for example, station 24002 (Gray’s Bridge on the River Camogue), station 24004 (Bruree on the River Maigue) and station 24022 (Hospital on the River Mahore), although none of these are close to any CARs.

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Rating Improve Station Station Station Proximity to Review Spatial No. Name Watercourse Status type CAR/IRR required? Coverage? 24001 Croom Maigue Active Recorder Croom Yes 24003 Garrose Loobagh Active Recorder Charleville Yes 24005 Athlacca Morningstar Active Recorder Yes 24006 Creggane Maigue Active Recorder Charleville Yes 24008 Castleroberts Maigue Active Recorder Adare Yes 24009 Adare Manor Maigue Active Recorder Adare Newcastle 24011 Deel Bridge Deel Active Recorder West Yes Grange 24012 Bridge Deel Active Recorder Rathkeale Yes Newcastle 24013 Rathkeale Deel Active Recorder West Yes 24015 Dromcolliher Ahavarragh Active Recorder Dromcolliher Yes 24016 Kilmallock Loobagh Inactive Recorder Kilmallock 24017 Robertstown Robertstown Inactive Recorder Foynes Inchirouke 24029 More Deel Active Recorder Askeaton Yes 24030 Danganbeg Deel Active Recorder Yes Staff Newcastle gauge Newcastle 24031 West Arra Inactive only West 24033 Ballyhahill White Active Recorder Ballylongford Riversfield 24034 Weir Loobagh Active Recorder Kilmallock Yes Staff gauge 24036 Golden Vale Ballincolly Inactive only Charleville Normoyle's Kildomo 24067 Bridge Greanagh Active Recorder New Staff gauge Kildomo 24081 Currachase Currachase Inactive only New 24082 Islandmore Maigue Active Recorder Yes Staff Kilmallock gauge 24084 Creamery Maigue Inactive only Kilmallock Table 3-A Key hydrometric stations identified for Shannon Estuary South (grey boxes indicate no data available)

3.3 Hydrometric network in relation to CARs and IRRs

As fluvial flooding is by far the most common cause of flooding at APSRs, with the exception of those noted in Tables 2-A and 2-B, it has been assumed that irrespective of the precise causes of historic flooding, observations from the nearest river gauge (ref. Figure 3) would be a useful indicator of flood risk.

Of the 12 Communities at Risk (CARs), 7 have hydrometric gauging stations located within the immediate locality all of which are loggers operated either by the OPW or co-ordinated by the EPA. A further CAR (Charleville) is located on a tributary in the upper reaches of the River Maigue catchment and it could be assumed that a

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suitable pivotal gauge (a gauge that can be used to assist in deriving flood estimates based on the hydrological similarity between the gauged site and the site for which flows must be derived) could be identified. Four CARs (Ballylongford, Kildomo New, Clarina and Foynes) do not have any flow or level gauges located within their catchment, and their small catchment size could be a potential hurdle to finding a suitable pivotal gauging site within the unit of management or more widely. Consideration should be given to improving the gauging network in these locations for the benefit of future flood studies.

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90000 100000 110000 120000 130000 140000 150000 160000 170000 180000 160000 160000

Clarina Kildimo New B a Foynes akyle lly arn (R n B ive ac Askeaton r) lo gh 24017 24019 (R Shannon Estuary i Tarbert Power Station 24032 24081 ve 24029 r) Glasha 150000 na 150000 gark (R iver) 24018 Adare 24033 24067 24009

Ballylongford ) W r e h v it i e 24008 R n ( ( 24035 u ly R a b 24007 r iv ) d r o co e e r og 24040 n r) e (Riv t am e (Rive le cronan a 24013 Croom C r) G Aha h g Ball r) a ylin e (Rive s 24002 s Rathkeale K i 24082 24038 ) r 24083 e 24041 i v 24001 l (R namona (Ri 140000 140000 y v ee all e r ) D B Da ar (R 24028 24022 iv 24020 e 24025 r ) 24027 er) 24012 M iv (R a 24005 M re i g a h o 24031 u 24021 e

Newcastle West ( R i w ve 24011 ka r ns ) e ) w 24004 m O M a 24042 e o r r t 24030 n S i ( 24084 n 130000 130000 g h s 24024 g t a 24046 24006 24003 Kilmallock a r n r (River) Ehe r) 24016 ve Ri 24045 a ( Bun sh 24036 24037 ok la e ing 24034 24039 (R F iv 24026 e ) L r) r o o b e Charlevile a v i g R 24014 h ( Dromcolliher )

r ( R h (Riv e g len i 24043 G v ll ila 24015 e Ki r )

) r 120000 120000 e iv ra ( R Mullahee Legend

Community at Risk (CAR)

Individual Risk Receptor (IRR)

Active Hydrometric Station

Inactive Hydrometric Station 110000 110000 River Network Shannon Unit of Management 24 Boundary

Project No. 32103000

Project Title Shannon CFRAMS Study

Drawing Title CARs and IRRs with Nearby Gauging Station Unit of Management 24 100000 100000

0204010 Kilometres

90000 100000 110000 120000 130000 140000 150000 160000 170000 180000 Figure 3 Location of hydrometric gauging stations in relation to Communities at Risk and Individual Risk Receptors within Shannon Estuary South

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3.4 Rainfall data

3.4.1 Background

Rainfall measurement in Ireland is coordinated by Met Éireann with data collected from their own raingauges and those operated by individual volunteers and organisations. Rainfall data is collected hourly, daily or monthly.

The majority of the approximately 750 raingauges located throughout Ireland are read daily, the remainder being monthly read gauges located in remote areas. Monthly readings are of little value to this study and will not be considered any further. Across Ireland, Met Éireann runs 15 sub-daily gauges, where rainfall is measured on an hourly basis, these provide valuable information on rainfall intensity. No details on the Met Éireann quality assurance procedures applied to rainfall data were available. This will be discussed in the Hydrological Report.

Met Éireann also operate two radars for rainfall detection, one at Dublin Airport and the other at Shannon Airport. These provide almost complete coverage of Ireland. Data from the radars are processed to produce a number of different products including intensity and periodic totals. This data will be used as part of this study when appropriate, but is unlikely to be sufficiently accurate to be used in calibration of models. However, it may be feasible to use the data in some form if suitable ground truthing is possible near to the location of interest. The radar data can provide useful information on the spatial extent of rainfall for particular events, when there are concerns about how widespread the event may have been.

The National Roads Authority (NRA) may be another potential source of sub- daily rainfall information. The NRA has recently established a network of sensors along major roads to measure and record the type and intensity of precipitation at 10 minute intervals. This information is used to help warn the NRA of extreme weather and warn drivers of road conditions. One NRA rainfall sensor is located within the Shannon Estuary South Unit of Management. Insufficient data was available at the time of writing of this report to determine the precision of the NRA rainfall sensors or to correlate the rainfall depths estimated from the sensors with Met Éireann daily raingauges. The accuracy of the data compared to traditional measuring devices therefore remains untested. With such uncertainty it was not deemed appropriate for use in this study.

3.4.2 Daily rainfall data

Daily rainfall depths are recorded at nine locations within the Shannon Estuary South Unit of Management. Storage raingauges are used to collect rainfall and are read and emptied daily at 09:00 hours. This daily threshold can result in a storm event being recorded over two consecutive days, potentially leading to an underestimation of daily rainfall depth compared to a 24 hour rainfall depth obtained over no fixed time period.

Table 3-B summarises the raingauges located within Shannon Estuary South and the availability of data. Figure 4 shows the distribution of the raingauge network. Two further stations 6011 and 4111 are also located within UoM 24. However, no information is available on these at present. Their use will be considered as necessary in the ongoing hydrological study.

It is noted that the use of rainfall data from other rainfall gauges outside UoM 24 (but close to it) could conceivably be useful. This may include sub-daily raingauges to

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the south in the Blackwater catchment. This will be done if considered appropriate, but its use is likely to be limited given the need to derive (and use) rainfall within the catchment.

Raingauge Data Raingauge name no. available 4611 Tarbert Island Yes 4811 Patrickswell (Dooneen) Yes 4911 Castlemahon Yes 5111 Rathkeale Duxtown Yes 5711 Newcastle West (Castle Demesne) Yes 5811 Meanus Yes 6205 (Unknown) No 6111 Shanagolden (Old Abbey) Yes 6311 Ballyhahill Yes Table 3-B Daily rainfall data available within Shannon Estuary South

3.4.3 Sub-daily rainfall data

Sub-daily or hourly rainfall is recorded at airports and TUCSON (The Unified Climate and Synoptic Observations Network) stations. At these locations rainfall is automatically measured by tipping bucket raingauges with 0.1 or 0.2 mm buckets. The nearest synoptic station to UoM 24 is north of the Shannon Estuary at Shannon International Airport.

There are no Met Éireann hourly rainfall stations located within the Shannon Estuary South.

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90000 100000 110000 120000 130000 140000 150000 160000 170000 180000 160000 160000

LIMERICK

B a akyle ll arn (R yn B ive ac r) lo gh 4811 (R i Shannon Estuary 4611 ve r) G lash A 150000 150000 anaga 6111 rk (Ri h ver) a c r o n a shanaskee (River) n r) Gla e e iv ) W ( R r R ( e h re v it i hi ) i e v s gran (River e n Aghana R o ( ( r l ) C ly R rb i o v nRATHKEALE c er u n ) a 6205 CROOM le d G er) o v 6311 r M i t Ball r) a R ylin (Rive a 5811 ( e i g e K h g i s a g u o s ) e r m e ( a Ri v R C l ( iv namona (R 140000 y iv 140000 5711 ee e all e r ) D r) B Daa 5111 r (Ri trea m ) ve S n (S r) lew nau ver) (Ri NEWCASTLE ) e D r M e or o iv a h R a ( l ar ly st Arr g a (River) ( M nin R iver) or 4911 w ka ns ) e m w B o a O e g r KILMALLOCK (R t ive (S r) 130000 130000 h g a n her E ) Lo ver ob (Ri a ha gh s ( Bun Fingl a Rive ok r) e ) ( ) R am er iv e CHARLEVILLE (Riv er ) tr n ) r Barra ow e (S ) n a h r iv h g e R a v ( r i y R h L r) Glen ( g ve a i Kill il a (R lay ab n la ) a r e 120000 120000 e B iv a (R Mullaheer

Legend

Raingauge (Daily)

Major Road River Network Shannon Unit of Management Boundary 110000 110000 Tow n

Project No. 32103000

Project Title Shannon CFRAMS Study

Drawing Title Daily Rainfall Recording Stations Unit of Management 24 100000 100000

0204010 Kilometres

90000 100000 110000 120000 130000 140000 150000 160000 170000 180000 Figure 4 Location of daily raingauges within Shannon Estuary South

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3.5 Hydrometric data

3.5.1 Background

The location of hydrometric stations in the Shannon Estuary South is shown in Figure 3. The majority of flow and level gauging stations within UoM 24 are located on the Rivers Deel and Maigue or their tributaries. A small cluster of flow measurement sites are located to the west of the River Deel on the River White and on the watercourses draining into the Robertstown River. Additional gauges are located on the Ballincurra Creek which drains Limerick City, however, in accordance with the scope these gauges will be considered along with Limerick City within the Shannon Upper and Lower Unit of Management (UoM 25/26).

Gauging stations within the Shannon RBD are generally located within natural sections and therefore generally do not have any purpose-built control structures to ensure critical flow e.g. a flume or weir. However, the majority of gauging station sites are located downstream of man-made structures, such as bridges. These structures will provide some stability to the rated section, but without critical flow there is unlikely to be a consistent relationship between flow and level. In addition, any geomorphological changes to the channel cross-section will result in further changes to the flow-level relationship.

Water levels are recorded at the majority of stations. However, ratings have only been developed at selected locations. Both flows and levels will be useful in this study.

Depending on the station configuration, flow and level measurements can either be discrete or continuous measurements in time. The EPA hydrometric register specifies three broad station types within the Shannon RBD, viz. staff gauge, flow measurement site and recorder:

Staff gauge – this is a fixed plate with levels marked on, which is used to read off the water level during visits. This will provide a record of discrete water levels with limited use for flood estimation purposes. However, where no other flow or level data is available, staff gauge readings may be used to obtain some indication as to the behaviour of water levels at a given location. Staff gauge stations for which check gaugings (spot flow gaugings) are available are also referred to as flow measurement sites. Flow measurement sites are also of limited use for flood estimation purposes, except where check gaugings have been taken at high flows.

Recorder – Indicates a station fitted with a staff gauge and an automatic water level recorder to provide an instantaneous and (near-) continuous data record. The automatic level recorder can either be an autographic recorder or a digital datalogger. An autographic recorder is a simple float-operated device that records the water level by activating a pen marking the water level on a chart. These charts are then digitised to convert the data to a digital format. A datalogger is a device that records water levels in digital format at regular intervals of time. Both types of recorder can be considered continuous for fluvial and tidal flood analysis purposes.

Autographic recorders are gradually being replaced by digital data loggers within the Shannon RBD. This removes the requirement to digitise the records and also allows the transmission of the water level data via telemetry.

Check gaugings may also be available at recorder sites and are used to develop or confirm the rating relationship between the level and flow.

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3.5.2 Instantaneous flow and level data

Level data measured either via autographic recorder or at regular intervals by a data logger will be collectively treated as intanteneous and continuous data. Water levels recorded by an autographic recorder are digitised at inflection (or change) points and should therefore reliably capture any significant changes to the water levels at a site.

Instantaneous data for varying periods of record is available at 28 stations within UoM 24 (Table 3-C). These stations are located on Figure 5 along with their current status (active or inactive). Jacobs have been advised that not all data from autographic recorders has been digitised and uploaded onto the archives and will therefore not be readily available for this study. However, for specific events, such data may be of benefit (which will require digitising by OPW) and will be requested as the need for such data arises. Data listed in Table 3-C outlines all the instantaneous digital data available and provided to Jacobs.

Instantaneous flow and level data are useful for event analysis as it provides a greater temporal resolution than the daily mean flow and level series. This is especially important for analysing events in fast-responding flashy catchments.

3.5.3 Daily mean flow or level data

Daily mean flow and level data is derived from instantaneous flow or level series. Daily mean flow data is useful when seeking a long-term view of the flow or level record to help identify any trends or sudden shifts in the dataset and to obtain an understanding of the behaviour of flows at a given location.

Initially, all daily mean flow and level data was obtained via the OPW Hydro-Data website (http://www.opw.ie/hydro/). The OPW later provided daily mean flows for the OPW stations listed as requiring a rating review (ref. Table 3-D). In some instances the two data series for a given station were not consistent; where this was the case the data provided directly by the OPW was used.

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90000 100000 110000 120000 130000 140000 150000 160000 170000 180000 160000 160000

LIMERICK

24061 Ba akyle ll arn (R yn B ive ac r) lo gh 24017 (R Shannon Estuary i ve 24029 r) Gl asha A 150000 naga 150000 rk (Ri h ver) a c r o 24062 24033 n a ashanaskee (River) n 24067 r) Gl e e 24009 iv ) Wh ( R r R ( e re v it i hi r) i e v s agran (Rive e n 24008 Aghan R o ( ( r l ) ly R C rb i o v nRATHKEALE c er u n ) a CROOM le d G r) o 24013 ve r M i Bal ) t R lylin River a a ( e ( i 24002 e K h g 24082 g is a g u o s ) e r m e ( a Ri v R 24001 C l ( iv namona (R 140000 140000 y iv ee e all e r) D r) B D aar ( Rive r) 24022 ) 24012 River NEWCASTLE ( D ) 24005 er M re o iv a ho a 24100 (R ll r y sta Arr ( g a (River) R M nin iver) 24011 o r w ka ns ) e 24004 m w B o a O e g r 24030 KILMALLOCK (R t ive (S r) 130000 130000 h g 24016 a 24006 n 24046 her E ) Lo 24034 iver ob (R 24003 a ha gh 24045 s ( Bun ingla Riv o F er) ke ) ( m ) R a er ive e CHARLEVILLE Riv r ) tr n ( ) r Barran ow e (S ) a h r iv h g e R a v ( r i 24015 y R h L r) Glen ( g ve a Ri Kill il a ( lay ab n la ) a r e 120000 120000 e B iv ( R Mullaheera Legend

Active Hydrometric Station

Inactive Hydrometric Station

Major Road River Network Shannon Unit of Management Boundary 110000 110000 To w n

Proje ct No. 32103000

Proje ct Title Shannon CFRAMS Study

Draw ing Title Hydrometric Stations Unit of Management 24 100000 100000

0204010 Kilometres

90000 100000 110000 120000 130000 140000 150000 160000 170000 180000 Figure 5 Location of hydrometric gauging stations within Shannon Estuary South Unit of Management

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Station UoM24 sub- Station 15 min 15 min 15 min 15 min Station name Watercourse number catchment status flow start3 flow end3 level start level end 24001 Croom Maigue Maigue Active 01/10/1972 09/09/2010 01/10/1972 09/09/2010 24002 Gray's Br Camoge Maigue Active 01/10/1972 10/09/2010 24003 Garroose Loobagh Maigue Active 01/10/1972 10/09/2010 01/10/1972 10/09/2010 24004 Bruree Maigue Maigue Active 01/10/1972 10/09/2010 01/10/1972 10/09/2010 24005 Athlacca Morningstar Maigue Active 01/10/1972 10/09/2010 01/10/1972 10/09/2010 24006 Creggane Maigue Maigue Active 01/10/1972 10/09/2010 24008 Castleroberts Maigue Maigue Active 01/01/1977 10/09/2010 28/11/1973 10/09/2010 24009 Adare Manor Maigue Maigue Active 01/11/2007 10/09/2010 24011 Deel Br Deel Deel Active 01/01/1989 10/09/2010 01/01/1989 10/09/2010 24012 Grange Br Deel Deel Active 01/10/1954 09/09/2010 01/10/1954 09/09/2010 24013 Rathkeale Deel Deel Active 01/10/1972 10/09/2010 01/10/1972 09/09/2010 24016 1 Kilmallock Loobagh Maigue Inactive 24/07/1980 17/04/1984 24/07/1980 17/04/1984 24017 1 Robertstown Robertstown Other Inactive 21/10/1981 15/05/2000 21/10/1981 15/05/2000 24022 1 Hospital Mahore Maigue Active 12/06/1984 27/10/2010 24029 1 Inchirourke More Deel Deel Active 12/10/1982 29/08/1995 12/10/1982 03/05/2011 24030 1 Danganbeg Deel Deel Active 05/05/1980 03/05/2011 05/05/1980 05/01/2011 24033 1 Ballyhahill White Other Active 28/07/1980 04/01/2011 24034 Riversfield Weir Loobagh Maigue Active 16/07/2004 21/09/2010 16/07/2004 21/09/2010 24045 1 Cantogher Bunoke Deel Active 09/07/2007 11/05/2010 24046 1 Gortnaluggin Br Finglosha Deel Active 05/08/2004 07/10/2010 24047 2 Rossbrien Rly Br Ballinacurra Ballinacurra Active 01/01/2000 23/07/2008 24048 2 Ballinacurra DS Ballinacurra Ballinacurra Active 01/01/2000 01/08/2004 24049 2 Ballinacurra US Ballinacurra Ballinacurra Active 01/01/2000 04/11/2006 24061 Ferry Br Maigue Estuary Tidal Active 01/01/2000 31/08/2010 24062 Adare Quay Maigue Estuary Tidal Active 30/11/2007 09/09/2010 24067 Normoyle's Br Greanagh Other Active 30/11/2007 10/09/2010 24082 Islandmore Maigue Maigue Active 03/11/1975 24/08/2010 03/11/1975 24/08/2010 24100 Gortboy Hotel Deel Deel Active 29/10/2008 10/09/2010 1 Instantaneous data from the EPA is a combination of regular 15 minute data (from data loggers) and irregular data based on digitised chart data (from autographic recorders); 2 Limerick City (and therefore the Ballinacurra catchment) have been scoped within the Upper and Lower Shannon Unit of Management (UoM 25/26); 3 Grey boxes indicate no data available. Table 3-C Instantaneous flow and level data available within UoM 24 and their period of record

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Daily mean flow data Daily mean level data UoM 24 sub- Station no. Station name River catchment Record start Record end Record start Record end

24001 Croom Maigue Maigue 01-Oct-71 09-Sep-10 01-Oct-72 09-Sep-10 24002 Gray's Bridge Camoge Maigue 01-Jan-79 05-Oct-03 24003 Garroose Loobagh Maigue 01-Oct-72 10-Sep-10 01-Oct-72 10-Sep-10 24004 Bruree Maigue Maigue 01-Oct-72 31-Dec-03 01-Oct-72 30-Jan-05 24005 Athlacca Morningstar Maigue 01-Jan-80 21-Dec-02 24006 Creggane Maigue Maigue 30-Dec-77 01-Jan-78 01-Oct-72 10-Sep-10 24008 Castleroberts Maigue Maigue 28-Nov-73 12-Jul-10 28-Nov-73 10-Sep-10 24011 Deel Bridge Deel Deel 02-Jan-89 31-Dec-03 02-Jan-89 10-Sep-10 24012 Grange Bridge Deel Deel 01-Oct-54 02-Apr-07 02-Oct-54 02-Apr-07 24013 Rathekeale Deel Deel 01-Oct-72 10-Sep-10 01-Oct-72 10-Sep-10 24034 Riversfield Weir Loobagh Maigue 16-Jul-04 10-Sep-10 16-Jul-04 10-Sep-10 24082 Islandmore Maigue Maigue 01-Nov-77 20-Feb-01 01-Nov-77 20-Feb-01 Table 3-D Daily mean flow and level data available within UoM 24 and their period of record (Grey boxes indicate no data available)

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3.5.4 OPW quality codes

To assist users of daily mean and instantaneous flow and level data, the OPW have assigned quality codes to each flow or level value. The quality codes indicate whether the data has been checked and if so, what confidence the OPW have in the data. Quality codes assigned by the OPW have been grouped into broader classifications for this study as outlined in Table 3-E. Where quality codes did not match an OPW code, they were classed as ‘unknown’. These quality codes will be referred to as necessary when considering how the data is to be used.

OPW OPW Description Jacobs Code classification WATER LEVEL DATA 1 Unchecked digitised water level data – Data is provisional only and must be used with caution Unchecked 31 Inspected water level data – Data may contain some error, but has been approved for general use Good 32 As per Code 31, but where the digitised water level data has been corrected Good 99 Unchecked imported water level data – Data is provisional only and must be used with caution Unchecked 145 Data is below prescribed data range and must only be used with caution Beyond Limits 146 Data is above prescribed data range and must only be used with caution Beyond Limits 150 Partial statistic – Data has been derived from records that are incomplete and do not necessarily represent the true value Caution 101 Unreliable water level data – Data is suspected of being erroneous or is artificially affected (e.g., during drainage works) and must only be used with caution Caution >150 Data is not available as it is missing, erroneous or of unacceptable quality Missing ESTIMATED FLOW DATA 31 Flow data estimated using a rating curve that it is considered to be of good quality and inspected water level data – Data may contain some error, but is considered to be of acceptable quality for general use Good 32 As per Code 31, but using water level data of Code 32 Good 36 Flow data estimated using a rating curve that it is considered to be of fair quality and inspected or corrected water level data – Data may contain a fair degree of error and should therefore be treated with some caution Fair 46 Flow data estimated using a rating curve that it is considered to be of poor quality and inspected or corrected water level data – Data may contain a significant degree of error and should therefore be used for indicative purposes only Poor 56 Flow data estimated using an extrapolated rating curve (see Section 3.2) and inspected or corrected water level data – Reliability of data is unknown and it should therefore be treated with caution Caution 99 Flow data that has been estimated using unchecked water level data – Data is provisional only and must be used with caution Caution 101 Flow data that has been estimated using unreliable water level data – Data is suspected of being erroneous and must only be used with caution Caution 145 Data is below prescribed data range and must only be used with caution Beyond Limits 146 Data is above prescribed data range and must only be used with caution Beyond Limits 150 Partial statistic – Data has been derived from records that are incomplete and do not necessarily represent the true value Caution >150 Data is not available as it is missing, erroneous or of unacceptable quality Missing

Table 3-E OPW quality codes and corresponding Jacobs classification

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3.5.5 Annual maximum flow and level data

The annual maximum flow or level is derived from the highest recorded value in a continuously measured flow or level data series for a hydrometric year (1 October to 30 September).

Annual maximum (AMAX) data was provided from two sources, the OPW and the FSU (via the OPW). Where both sets of data were available for a location, the OPW advised that the former series be used in preference, due to the additional work undertaken to extract the peak flows. The FSU series was developed for the Flood Studies Update in 2005/6 and accordingly the series ends in 2004. AMAX data was available at 19 hydrometric stations, including 3 tidal gauges (24061, 24062 and 24067) located within UoM 24 (Table 3-F). The annual maximum flow series at 24100 is currently too short (3 years) to be of much use in subsequent statistical analysis, but has been included for completeness.

AMAX AMAX Station AMAX (Flows) (Levels) (Flow) (from number Station name Waterbody (from OPW) (from OPW) FSU)* 24001 CROOM MAIGUE 1977-2009 1953-2009 24002 GRAY'S BR. CAMOGE 1972-2009 24003 GARROOSE LOOBAGH 1980-2009 24004 BRUREE MAIGUE 1953-2009 1953-2009 24005 ATHLACCA MORNINGSTAR 1953-1969 1953-2009 24006 CREGGANE MAIGUE 1998-2009 24008 CASTLEROBERTS MAIGUE 1977-2009 1975-2009 24009 ADARE MANOR MAIGUE 1973-2009 24011 DEEL BR. DEEL 1972-2009 1972-2009 24012 GRANGE BR. DEEL 1964-2009 1964-2009 24013 RATHKEALE DEEL 1953-2009 1953-2009 24022 HOSPITAL MAHORE 1985-2004 24030 DANGANBEG DEEL 1980-2004 RIVERSFIELD 24034 WEIR LOOBAGH 1985-2009 1985-2009 MAIGUE 24061** FERRY BR. ESTUARY 1960-2009 MAIGUE 24062** ADARE QUAY ESTUARY 1993-2009 24067** NORMOYLE'S BR. GREANAGH 1993-2009 24082 ISLANDMORE MAIGUE 1977-2009 1977-2009 24100 GORTBOY HOTEL DEEL 2007-2009 2007-2009 * Details of FSU AMAX only recorded if no flow or level annual maxima data is available from the OPW. ** Tidal stations Table 3-F Annual maximum flow and level data for hydrometric gauges located within UoM 24 (NB: FSU AMAX flow series only listed if AMAX flow series was not available from the OPW)

3.5.6 Hydrometric station rating reviews

A rating curve defines the relationship between water levels and flows for a given location. The rating curve is usually established as the line of ‘best fit’ to check gaugings measured at the gauged location throughout a range of flows and

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levels.The rating is often described using one or more rating equations, so that flows can be estimated for any water level (within the range). Abrupt changes in the cross section width (e.g. where the cross section changes from in-bank to out-of-bank) may result in transitions (in the form of ‘kinks’) in the rating curve. Multiple rating equations may be required to adequately describe the segments of the rating curve between these transition points. There may not be a consistent relationship between flows and levels. This can be a result of an unstable cross-section, where the rating may change over time, making the rating equations invalid until new equations are established. Actual flows may vary for a given water level as a result of hysteresis, blockage, instability of the cross-section, or hydraulic backwater effects.

Table 3-G and Figure 6 illustrate the gauging stations for which rating reviews are required. Table 3-G also details stations for which rating equations and check gaugings have been provided. No rating equations have been provided for stations requiring a rating review that are managed by the EPA, stations 24015, 24029 and 24030.

Rating Check UoM 24 review Rating flow Station sub- required by equations gaugings number Station name River catchment the OPW? received? received? 24001 Croom Maigue Maigue Yes Yes Yes 24003 Garroose Loobagh Maigue Yes Yes Yes 24004 Bruree Maigue Maigue No Yes Yes 24005 Athlacca Morningstar Maigue No Yes Yes 24006 Creggane Maigue Maigue Yes Yes Yes 24008 Castleroberts Maigue Maigue Yes Yes Yes 24009 Adare Manor Maigue Maigue No No Yes 24011 Deel Br. Deel Deel Yes Yes Yes 24012 Grange Br. Deel Deel Yes Yes Yes 24013 Rathkeale Deel Deel Yes Yes Yes 24015 Dromcolliher Ahavarragh Deel Yes No No 24029 Inchirouke More Deel Deel Yes No No 24030 Danganbeg Deel Deel Yes No No 24034 Riversfield Weir Loobagh Maigue Yes Yes Yes 24046 Gortnaluggin Br. Finglosha Deel No No Yes 24067 Normoyle's Br. Greanagh Maigue No No Yes 24082 Islandmore Maigue Maigue No Yes Yes 24100 Gortboy Hotel Deel Deel No No Yes Table 3-G Summary of gauging station rating reviews required and rating equations and check gaugings provided.

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90000 100000 110000 120000 130000 140000 150000 160000 170000 180000 160000 160000

Ba akyle lly arn (R n B ive ac r) lo gh (R Shannon Estuary i ve 24029 r) Gl asha A 150000 150000 naga rk (Ri h r) ver a ) ive c R r ( o h n ag a n ver) n a M Glashanaskee (Ri n e a a e i ) W ( r g r R e h G u v i i e i te v River) 24008 gran ( e ( hana R Ag R ( ( r ) ly R b i iv r v n e o C r c e u ) n r a l e ) o l d 24013 ) G n r o 24001 e r s iv Bally r) t h (R lin e (Rive a ir K h e ge is a g ( o s ) R r iv m e e a i v r C l (R ) namona (Ri 140000 v 140000 ee ally e r ) D B Da tre ) ar (S a m (R S l aun iv ewn e r ) 24012 River) D ( r) M e o e or a iv a h R l ( ly tar ( 24011 gs Arra (River R M in ) iver) o rn aw sk ) n Ba e lly m w B an o a O i ) g e a tream ) r 24030 ( S m (R t a iv S re er ( St ) 130000 130000 ( h un g ishna a 24006 atr n Ah er Eh Lo 24034 r) ob ive 24003 a R gh a ( ( Bun sh Rive ok la r) e ing ) ( F m ) R a er iv e Riv er ) tr n ( ) r S Barran ow e ( ) a h r v i h g e R a v ( r i 24015 y R h L r) len ( g e G a Riv Kill il a ( lay ab n la ) a r e 120000 120000 e B iv ra ( R Mullahee

Legend

Hydrometric Station Re quiring Rating Review 110000 110000 River Network Shannon Unit of Management 24 Boundary

Project No. 32103000

Proje ct Tit le Shannon CFRAMS Study

Dr awing Title Hydrometric Stations for Rating Review Unit of Management 24 100000 100000

0204010 Kilometres

90000 100000 110000 120000 130000 140000 150000 160000 170000 180000 Figure 6 Hydrometric gauging stations within Shannon Estuary South requiring a rating review

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3.5.7 Check gaugings

Frequent check gaugings (spot flow gaugings) are required across a range of flows to establish and maintain a rating relationship. For this study, where flood flows are of particular significance, frequent check gaugings at high flows are essential to ensure confidence in flood flow estimates.

Check gaugings will be reviewed in association with the rating equations as part of the rating reviews and high flow suitability assessments to be undertaken later in the project.

A summary of stations for which check gaugings have been provided is given in Table 3-G.

3.5.8 Gauging station visits

Hydrometric gauging stations requiring a rating review as stated in the OPW brief (Table 3-G) were visited by Jacobs staff and observations recorded on the Gauging Station Summary Sheets (Appendix H).

3.6 Coastal data

OPW have provided the results from the Irish Coastal Protection Strategy Study (ICPSS). This gives extreme tidal peak levels for the following annual probabilities: 50%, 20%, 10%, 5%, 2%, 1%, 0.5%, 0.1% for the south western coast and the Shannon Estuary.

OPW has also provided results from the ICWWS (Irish Coastal Wave & Water Level Modelling Study) screening analysis which highlight coastal locations potentially vulnerable to wave overtopping for the south western coast and the Shannon estuary.

For these locations, detailed wave and still water level model outputs are available in the form of shoreline prediction points and their associated predicted water level and wave climate (wave height Hmo, period Tp and mean direction) combinations for a range of annual probabilities (50%, 20%,10%, 5%, 2%, 1%, 0.5% and 0.1%). These outputs include both the current condition and two future scenarios (Mid Range Future Scenario [MRFS] and High End Future Scenario [HEFS]).

3.7 Flood Studies Update

Following its publication in 1975 (NERC) the Flood Studies Report was adopted as the standard approach for flood estimation in Ireland. In 2004, the Flood Policy Review Group recognised that, with advances in flood estimation along with an additional 30 years of flow data, the development of new or recalibrated flood estimation methods could significantly improve the quality and facility of flood estimation in Ireland. Since 2005, the OPW have been implementing the Flood Studies Update (FSU) programme. Revised methodologies arising from the study have not yet been publicly distributed, but the package of works is complete and will be tested within this study.

A summary of the main work packages relevant to this study is outlined below.

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3.7.1 Work Package 1.2 – Estimation of point rainfall frequencies

A rainfall depth duration frequency model was developed for Ireland that allows point rainfall estimates to be made for durations from 15 minutes to 25 days and for Annual Exceedance Probabilities (AEP) down to 0.002% (0.004% AEP for durations less than 24 hours). The model uses median rainfall as the index rainfall and log- logistic growth curves to determine rainfall with other frequencies. The associated software allows annual exceedance probability of rainfall to be mapped at a 2 km grid and rarity estimates to be made for point measurements (on a sliding scale). This information has been used within this study to assess extreme rainfall events and to inform the assessment of flood events. At a sample of sites the output from the Depth Duration Frequency (DDF) software has been compared to measured rainfall frequency (ref. Section 6.7).

3.7.2 Work Package 2.1 – Flood flow rating review

Within this package of works, flow data from the OPW, EPA and ESB was collated and reviewed by Hydrologic between July 2005 and March 2006, with the aim of identifying sites which had a useable AMAX series and stage-discharge relationships from which accurate high and flood flows could be obtained. To assist with the review, a gauging station classification was developed, which grouped stations of interest as A1, A2, B or C (ref. Table 3-H).

FSU Classification Definition Suitable for flood frequency analysis. These were sites where the highest gauged flow (HGF) was significantly higher than the median annual flood (Q ) [HGF > 1.3 x Both med Qmed] and it was felt by the OPW that the ratings provided a reasonable representation of extreme flood events A Confirmed ratings for flood flows well above Qmed with the HGF > than 1.3 x Q and/or with a good confidence A1 med of extrapolation up to 2 x Qmed, bankfull or, using suitable survey data, including flows across the flood plain. Rating confirmed to measure Qmed and up to around 1.3 A2 x Qmed. At least one gauging for confirmation and good confidence in the extrapolation. Flows can be estimated up to Qmed with confidence. B Some high flow gaugings must be around the Qmed value. Sites within the classification have the potential to be upgraded to B sites but require more extensive gauging C and/or survey information to make it possible to rate the flows to at least Qmed. Table 3-H FSU gauging station classification (from Hydrologic, 2006)

No indication is given in the report as to the total number of gauging station reviewed, only the number of sites selected as A1, A2 and B and therefore considered suitable for flood analysis, as summarised in Table 3-I. Please note some stations have their records split over different periods of time in which case each period is classified separately as a record.

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Number of FSU Total number of Number of records records in Classification records in UoM 24 Shannon RBD A1 75 18 1 A2 119 22 4 Total A sites 194 40 5 B 103 11 4

Table 3-I Number of stations suitable for flood flow analysis classified A1, A2 or B

This FSU classification has been borne in mind when reviewing flood flows and will form the basis of high flow quality assessments undertaken later in the project. Table 3-J summarises the eight FSU rating reviews and classifications for the separate periods of record within UoM 24.

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Station Name Station River FSU Rating remarks (limit of reliable extrapolation, stability, concerns over particular gaugings, (period of Number Name Classification assumptions made etc) record)

Rating history reviewed HL rating created for period. Insufficient confidence to extrapolated. Bankfull level will Croom (Pre Maigue A2 help. Limit of rating 0.2m - 3.5m (ASGZ). Some scatter at top end. More high flow gaugings needed to have 28/07/76) confidence in extrapolation 24001 Rating history reviewed HL rating created for period. Insufficient confidence to extrapolated. Bankfull level will Croom (Post Maigue A2 help. Limit of rating 0.5m - 3.5m (ASGZ). Some scatter at top end. More high flow gaugings needed to have 26/10/77) confidence in extrapolation Gray's Bridge (Post Camoge A2 17/05/1978 ) 24002 Gray's Bridge (Pre Camoge B 17/05/1978 ) No major datum changes to account for large number of high flow ratings. Channel excavation on 16/4/81 doesn't seam to have had a significant impact on the channel ratings. Insufficient confidence to extrapolate past 24004 Bruree Maigue B HGF (37 cumecs). Bankfull level will help confirm limit of extrapolation. Some scatter at top end. More high flow gaugings needed. 24008 Castleroberts Maigue A2 Use existing rating RC1 for POR. Extrapolate to 2.5m allows site to be A2 (Level assumed from site photo). HL high flow rating developed. Rating OK . Maximum extent of extrapolation 3.0m. More high flow gaugings Deel Bridge (post Deel B needed to confirm top end. Minimum extrapolation 0.5m as a significant amount of scatter below this. Spring 01/10/1962) 24011 line of arches approx 3.2m and soffit of keystone approx 4.5mSG. Deel Bridge (pre HL high flow rating developed. Rating OK but few gaugings. Maximum extent of extrapolation 3.0m. Minimum Deel B 01/10/1962) extrapolation 0.3m as no gaugings below this. Grange Bridge Reasonable rating, scatter particularly at low flows. Minimum limit of rating 0.8m. Maximum extent of Deel B (post 28/09/1964) extrapolation 3.4m (bankfull). 24012 Grange Bridge (pre Deel B Reasonable rating, few gaugings particularly at low flows. Maximum extent of extrapolation 2.84m (HGF). 28/09/1964) Rathkeale (post Deel A1 Use RC12 post drainage in the range 1.0m to bankfull at 4.4m. 01/01/68) 24013 Rathkeale (pre Deel A1 Use RC3 pre drainage for POR in the range 1.0m to bankfull at 4.4m. 01/01/64) Use RC1 for POR. Bankfull levels need to be established before extrapolation can be assessed. Could be A1 if 24082 Islandmore Weir Maigue A2 bankfull near 1.8m. Table 3-J Summary of FSU Rating Classification for hydrometric stations within UoM 24.

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3.7.3 Work Package 2.2 – Flood frequency analysis

Work Package 2.2 covers the development of techniques with which to estimate the design flood for a range of exceedance probabilities for rivers in Ireland. The recommended methods are broadly analogous to those specified in the UK Flood Estimation Handbook but with Ireland specific equations to reflect the differing hydrological conditions. These differences are expressed in the AMAX data having a lower variability and skewness than commonly found elsewhere.

The procedures are based on the AMAX series from approximately 200 gauging station records with lengths ranging from 10 to 55 years. A subset of these, made up of 85 sites with the best records, was used for the most detailed analyses.

Guidance is provided on the estimation of design flows at gauged and ungauged locations and on the estimation of uncertainty. It recommends the use of Qmed as the index flood. Gauged site data is preferred over any estimate from catchment descriptors. However synthetic estimates from catchment characteristics can be significantly improved by using pivotal sites. The use of growth curves or factors are applied to the index flood derived from regional pooling groups. The report concludes that whilst no single statistical distribution can be considered to be ‘best’ at all locations both the Extreme Value Type 1 (Gumbel) and the lognormal distributions provide a reasonable model for the majority of stations.

3.7.4 Work Package 3.2 – Hydrograph width analysis

Methods are developed to produce the ‘design flood hydrograph’ of given return period at gauged and ungauged sites in Ireland. For each site, the peak flow of the hydrograph so produced matches the corresponding ‘design flow’ provided by Work Package WP2.2: Flood Frequency Analysis’ for the same return period.

In the case of a gauged site, a non-parametric approach is applied to a set of observed flood hydrographs to estimate the characteristic flood hydrograph for the station. An alternative parametric form of ‘derived’ hydrograph is also developed whereby the non- parametric form is fitted by a 3-parameter curve.

For an ungauged site, regression-based expressions are used to estimate the values of relevant hydrograph descriptors which are then applied, following a parametric approach, to produce its characteristic flood hydrograph.

Characteristic flood hydrographs are, by rescaling, developed into the required design flood hydrograph.

3.8 Historical flood events

The flood history of the Communities at Risk and Individual Risk Receptors has been examined primarily using the www.floodmaps.ie website. Further details are presented in Section 8.

3.9 Outstanding data and recommendations

Rating review histories and check gaugings are outstanding for three gauging stations identified by the OPW as requiring a rating review, these are 24015, 24029 and 24030.

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4 Hydrological Estimation Points

4.1 Introduction

Section 6.5.3 of the Generic CFRAM Study Brief ‘Hydrological Estimation Points’ states that: “The consultant shall derive best estimate design fluvial flood parameters based on the methods referred to above at Hydrological Estimation Points. The Hydrological Estimation Points shall include all of the following:

• points on the HPW that are central within each APSR, and immediately upstream and downstream of the APSR, • all hydrometric gauging stations (as specified in the tender documentation of the Specific Tender Stage [Stage II]). • points upstream and downstream of the confluences of all tributaries that potentially contribute more than 10% of flow of the main channel immediately upstream of the confluence for a flood event of a particular AEP, • upstream boundaries of hydraulic models, and, • other points at suitable locations as necessary to ensure that there is at least one Hydrological Estimation Point every 5kms along reaches of all modelled river (i.e. either HPW or MPW).”

Following Jacobs’ Technical Note TD010, which detailed the proposed methodology and timing of defining the Hydrological Estimation Points (HEPs), a trial was carried out to identify potential issues related to the proposed methodology.

4.2 Methodology

For the reasons outlined in Section 4.0 of Jacobs’ Technical Note TD010, to avoid reworking of the data, the derivation of HEPs within the study area and corresponding catchments boundaries will be completed after the Inception Report Phase, but within 2 months of Jacobs receiving a final list of APSRs and resolution to any catchment area discrepancies.

To aid the identification of any problems with the proposed methodology, the HEP definition process was trialled for the whole of Unit of Management 24.

In this trial HEPs were determined applying the criteria set out in Section 6.5.3 of the Generic Brief, using the preliminary APSR boundaries. It should be noted that HEPs are only required along watercourses for which a hydraulic model is proposed (confirmed by OPW on 24th June 2011). For ease of application of the FSU design flood methods, HEP locations were chosen to be coincident with the nodes used in FSU to define catchment descriptors where this was reasonable. Where the catchment area to a HEP (upstream, centre and downstream of APSRs, upstream and downstream of confluences, gauging station locations, upstream boundaries of hydraulic models) differed from that to the nearest FSU node by more than 10% of the catchment area, the HEP location was moved to the precise critical location.

The HEPs for UoM 24 were defined in a point shapefile, and given an attribute field specifying the reference number of the FSU ungauged subcatchment that the HEP was coincident with. This will allow for a fast process of attributing FSU catchment descriptors to HEPs. HEPs that are not coincident with FSU nodes did not get a reference in the attribute field; however, this constitutes only a small number of TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc FINAL 31 of 100

HEPs (4 for this trial). Catchment descriptors for these HEPs will have to be attributed manually.

The results and HEP definitions for the trial area have been provided to OPW via Sharepoint.

4.3 Lessons Learned

The HEP definition trial resulted in the following lessons learned:

1. Generally the HEPs at the critical locations (i.e. hydrometric stations, confluences, etc.) were chosen coincident with the nearest FSU node available. An exception applies where moving the HEP to the nearest FSU node would result in a change in catchment area of 10% or more, in which case the HEP was placed at the critical location. 2. At confluences, it was generally found that three FSU nodes are coincident, representing the two contributing catchments and the combined catchment. It was decided that the HEPs would be positioned at the next FSU node upstream and downstream along the watercourse with the largest upstream catchment (where the difference in catchment area from the upstream node to the confluence was not more than 10%), and in the confluence itself for the watercourse with the smallest upstream catchment. If moving a HEP from the confluence to the nearest upstream or downstream FSU node would have resulted in a change in catchment area of 10% or more, then the HEP was placed in the confluence. To make it clear which HEP belongs to which subcatchment (watercourse), any HEP placed “in” a confluence was actually positioned approximately 10m upstream or downstream of the confluence dependent of whether it represents one of the tributary catchment or the combined catchment respectively. 3. At a confluence of watercourses which were both part of the proposed model extent, a HEP was defined for each tributary, even if one of the tributaries contributes less than 10% in catchment areas. 4. When the rules for HEP definition would result in the definition of two HEPs for one FSU node, then only one HEP was defined.

4.4 Conclusions

Based on the HEP definition trial, it was concluded that:

1. The trial allowed Jacobs staff to obtain experience in defining Hydrological Estimation Points (HEPs) along the proposed model extents. 2. Based on the experience obtained during the trial, the proposed methodology provided a good basis for the HEP definition work, noting the lessons learned described in Section 4.3 above.

4.5 Recommendations and Way Forward

Once the APSRs are agreed, and the HEP catchment boundaries have been confirmed following a review of FSU catchment boundaries by Jacobs (see Chapter 5 below), it is recommended that the HEPs are defined following the agreed methodology, noting the lesson learned as described in Section 4.3 above.

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5 Catchment Boundaries

5.1 Introduction

Following Jacobs’ Technical Note TD010, which detailed the methodology to compare different catchment boundary datasets, this chapter details the findings of the comparison of the different catchment boundaries for catchment UoM 24, which was carried out using the methodology as set out in the Technical Note.

5.2 Data

The datasets in Table 5-A were compared.

Title Description Comments WFD Areas Water Framework Directive Identical to Units of Management River Basin District boundaries. Boundaries. Derived from 20m Used to define Units of H-DTM (the hydrologically Management. corrected DTM) with some manual correction. Automatic Gauged Automatically generated outlines Automatically derived from 20m Catchment Boundaries for the gauged areas. H-DTM (the hydrologically corrected DTM). FSU Gauged Manually adjusted applied to Provided by OPW (from Oliver Catchment Boundaries catchments where area derived Nicholson via Rosemarie Lawlor). (Adjusted) from the automated FSU We understand that manual gauged boundaries varied by corrections have been applied to more than 5% from the hard 36 of the 216 catchments used in copy OPW catchment area the FSU. maps. Automatic Ungauged Automatically generated outlines Automatically derived from 20m Catchment Boundaries for the ungauged areas at FSU H-DTM (the hydrologically nodes. corrected DTM). OPW National Digital Digital Terrain Model provided Detailed but large amount of data Height Model (NDHM, by OPW, 5m grid, IFSAR data and hence cumbersome. Not Intermap 2009) with a vertical RMSE of hydrologically corrected. approximately 0.7m on slopes smaller than 20 degrees.

Table 5-A Catchment boundary and topographical data available for Shannon CFRAM study

The OPW also provided a river network shapefile. This network was also used to assess the local credibility of catchment boundaries.

In an email to Jacobs from OPW on 19th May 2011 Rosemary Lawlor explained the FSU (adjusted) dataset as follows:

“As part of the Flood Studies Update 216 gauges were identified as being suitable for use in the FSU analysis (FSU Stations). The areas of the catchments that were delineated by Compass Informatics were compared with the catchments areas that the OPW had on file for all of the 216 catchments. Where it was found (that) the areas differed by more than 5% it was decided that the OPW catchment boundaries would be used in preference to the Compass Informatics boundaries. This was the

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case for 36 FSU stations. The OPW boundaries were digitised from paper maps for these 36 stations and were used to replace the compass informatics boundaries for these stations. The FSU end product was effectively a combination of 180 catchment boundaries (from compass informatics) merged with the 36 OPW catchment outlines. This makes up the final FSU catchment outlines”

5.3 Methodology

It is important that the catchment areas are checked and a definitive set of catchment boundaries agreed with the OPW to allow:

• Accurate definition of catchment areas and hence design flows at each HEP; • Interfaces with adjacent CFRAM Study project areas to be consistent; • Allow FSU automated procedures to be used to derive design floods as appropriate (and allow any adjustments necessary to be properly documented).

We have undertaken a review of the catchment areas to the gauged locations as detailed below:

1. A map for Unit of Management 24 was produced to allow comparison of the Water Framework Directive (WFD) and Flood Studies Update (FSU) boundaries to the hydrometric gauging stations and identify discrepancies. 2. The WFD boundary (equal to the Unit of Management 24 boundary) was compared with the automatic gauged catchment outlines, paying particular attention to the areas where manual correction has been applied (as denoted by the manually adjusted gauged catchment boundaries). 3. Detailed plans were produced for areas where significant discrepancies were found. These maps present the WFD boundary where available, the automatic and manually adjusted (FSU) boundaries, and contours based on the OPW National Digital Height Model (NDHM, Intermap 2009). 4. An additional random check was undertaken to satisfy ourselves that the automatic ungauged catchment boundaries are reasonable compared to the NDHM.

This review has been undertaken with the aim of identifying differences in catchment areas of 10% or more as there is no one definitive catchment outline and all the datasets have some uncertainty associated with them. At the time of writing this Inception Report the process of defining the Areas of Flood Risk Review (AFRRs) had not been completed. This analysis is therefore only based on discrepancies of 10% or more in catchment sizes to hydrometric stations, Communities at Risk (CARs) and Individual Risk Receptors (IRRs). There is a risk that other discrepancies come to light as a result of additional sites requiring to be studied following the AFRR definition process. It is therefore recommended that the catchment boundary comparison is revisited once the AFRRs are defined.

5.4 Results of analysis

Figure 7 overleaf shows a comparison of the Water Framework Directive (WFD) boundary, the automatic boundaries and the manually adjusted (FSU) boundaries in UoM 24. The figure shows two discrepancy areas which affect the area to a gauging station by 10% or more. The effects of the discrepancies on the catchment area to the nearest defined CARs would be smaller than 10%. The only IRR in the catchment (Tarbert Power Station) is on a small island in the Shannon Estuary, without FSU nodes. The risk of tidal flooding is more relevant to this island than surface/fluvial flooding. TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc FINAL 34 of 100

The discrepancy areas have been labelled 24-1 and 24-2 in Figure 7. Both areas show discrepancies between the automatic and the manually adjusted boundaries. Discrepancy Area 24-2 occurs in an internal subcatchment boundary, where no WFD boundary exists.

It is important to note that the manually adjusted boundaries were derived from the automatic boundaries, updating them for only a few gauged catchments, where the gauging station was found to be relevant for hydrological analysis. As a consequence, the manually adjusted boundaries are not consistent for nested and adjacent catchments, as the catchments nested in or adjacent to the manually adjusted catchments have not been amended.

The contours on the 1:50,000 scale OSi mapping have been compared with contours derived from the OPW National Digital Height Model (NDHM, Intermap 2009) and generally show a good correlation, particularly in relatively flat areas with little vegetation. The NDHM is based on IFSAR data, with a reported vertical root- mean-square error of approximately 0.7m on slopes smaller than 20 degrees, and greater on steeper slopes.

110000 120000 130000 140000 150000 160000 170000 180000

Discrepancy 160000 Area 24-1 Clarina Kildimo New Foynes Askeaton

Adare 150000

Croom Rathkeale 140000

Newcastle West

Kilmallock 130000

FSU Ungauged Charleville Catchment 24-1483-5 Dromcolliher Random Check 120000

Discrepancy Legend Area 24-2 FSU Adjusted Boundary Hydrometric Stations HA24 Automatic FSU Gauged Boundary Flow Measurements Water Framework Directive Water Level Only (Unit of Management) Boundary 110000 River Network Water Level and Flow

Individual Risk Receptor (IRR) Unknown 010205 Community at Risk (CAR) Kilometres

Figure 7 Catchment Boundaries Overview

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5.4.1 Discrepancy Area 24-1 – Dunvullen (Doonvullen)

Discrepancy Area 24-1 (approximate size 10 km2) is shown in detail in Figure 8 below. The figure shows a significant discrepancy between the automatic and the manually adjusted boundaries. The differences between the WFD boundary and the automatic boundary are negligible.

As described above, the adjusted boundaries are not consistent for nested and adjacent catchments, as the catchments nested in or adjacent to an adjusted catchment would not have been amended. In this particular area, the catchment boundaries to gauging stations 24001, 24008, 24082, etc. have not been corrected and follow the automatic boundary (see the red lines representing the automatic boundary). Only catchment 24002 was amended to exclude the discrepancy area based on historical OPW catchment boundary hardcopy maps.

In Figure 8 contours with a 5m vertical interval derived from the NDHM were superimposed on the OSi mapping. Analysis of the contours would suggest that some of the discrepancy area drains northwards. However, the figure includes the Shannon river network (in blue) and this shows that the manually adjusted boundary intersects a watercourse (Ahnavar/Groody River), which suggests that the adjusted boundary may not be accurate. The discrepancy may be caused by local errors in the river network dataset, errors in the NDHM (or the contours derived from this dataset), or the local rivers sloping against the general ground level gradient, draining southwards instead of northwards as the ground levels would suggest. This discrepancy may be resolved by a site visit possibly followed by a small topographic survey to confirm the gradients of the local river network.

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Copyright Ordnance Survey Ireland. All rights reserved. Licence number EN0021011 OPW NDHM 5m Interval Contours

Approximate scale 1 : 40,000 Figure 8 Discrepancy Area 24-1 (Dunvullen)

5.4.2 Discrepancy Area 24-2 – Galbally

This is another discrepancy (of approximately 2 km2) between the automatic and manually adjusted boundaries. Figure 9 shows the automatic boundary, manually adjusted (FSU) boundary, and an estimated boundary based on the NDHM (in blue). The manually adjusted boundary is intersected by rivers (as indicated by the river network dataset). Analysis of the NDHM contours suggests that this error is due to an error in the manually adjusted boundary. As this boundary discrepancy is at an ‘internal’ boundary within the unit of management, there is no WFD boundary available for comparison.

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NDHM 5m Interval Contours

Estimated Catchment Boundary from NDHM

Approximate scale 1 : 25,000 Figure 9 Discrepancy Area 24-2 (Galbally)

5.4.3 Random check

For UoM 24 the catchment area to one CAR was checked against the NDHM contours with a 5m vertical interval. The area chosen was the catchment to Dromcolliher, at the nearest ungauged FSU node (node number: 24-1483-5, area 5.4 km2). The results are shown in Figure 10 below. There appears to be a good correlation between the automatic catchment boundary and the contours, particularly considering the location of watercourses as indicated by the river network dataset.

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136000 137000 138000 139000

Copyright Ordnance Survey Ireland. All rights reserved. 5 1 1 Licence number EN0021011 0 10 1 1 0 2 5 5

0 1 122000 2 1 3 1 0 0

5 115

11 0 125

5 120 1 1

125 1 Dromcolliher 130 1 5 145 0 2 5 40 1 1 1 1 1 155 70 160 121000 120

0 8 135 18 1 0 5 7 1 1 65 0 0 6 1 9 1 50 1

17 175 0 180

170 18 1 5 120000 190 185 9 180 165 0 195 175 180 225 185 17 5 1 9 0 215 230 240 140 Legend 5 13 0 Ungauged FSU Catchment Hydrometric Stations SH240 2 0 Boundary (24-1483-5) 5 255 2 3 Flow Measurements 50 5 2 0 1 2 23 0 OPW NDHM 5m Contour

2 1

5 2 24 River Network Water Level Only 5 12 Community at Risk (CAR) Water Level and Flow 0 0120.5 119000 0 125 21 Kilometres Ungauged FSU Node Unknown

Figure 10 Random Check Area UoM 24 (Dromcolliher, FSU catchment 24-1483-5)

5.5 Conclusions

Based on the assessment of Unit of Management 24 alone, it was concluded that:

1. The manually adjusted (FSU) boundaries were derived from the automatic boundaries, revising them for only a few gauged catchments, where the gauging station was found to be relevant for hydrological analysis. As a consequence, the manually adjusted boundaries are not consistent for nested and adjacent catchments, as the catchments nested in or adjacent to the manually adjusted catchments would not have been amended.

2. The contours on the 1:50,000 scale OSi mapping have been compared with contours derived from the OPW National Digital Height Model (NDHM, Intermap 2009) and generally show a good correlation, particularly in relatively flat areas with little vegetation. The NDHM is based on IFSAR data, with a reported vertical root-mean-square error of approximately 0.7m on slopes smaller than 20 degrees, and greater on steeper slopes.

3. Inspection of the Water Framework Directive (WFD) boundary, the automatic boundaries and the manually adjusted boundaries shows two discrepancy areas which may affect the area to a gauging station by 10% or more. In both cases

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the manually adjusted boundary intersects with watercourses defined in the River Network dataset and on the OSi mapping. It is understood that the WFD and automatic boundaries are both based on hydrologically corrected DTMs, which may explain why their boundaries differ from the boundaries found using contour maps alone (manually adjusted boundary and NDHM contours).

4. One additional random check was carried out in catchment UoM 24 to compare an automatic ungauged FSU catchment boundary to a Community at Risk (CAR) with the NDHM dataset. For the catchment checked the automatic boundary compared well with the contours with 5m vertical interval generated from the NDHM.

The data used for this comparison is provided electronically using the Sharepoint system, see Appendix G.

5.6 Recommendations

It is recommended that the two discrepancies detailed above are further investigated. A site visit, possibly followed by some topographic survey should provide conclusive evidence with regard to the correct catchment boundaries for each discrepancy area.

5.7 Way forward

It is proposed that Jacobs and OPW have a discussion regarding the catchment boundary discrepancies after all Units of Management within the Shannon River Basin District have been analysed (UoM 23, UoM 24, UoM 25/26, UoM 27, UoM 28), so that the discrepancies can be addressed with a consistent approach for the whole River Basin District.

Jacobs suggests that OPW review the data provided herewith and, in discussion with Jacobs, advise Jacobs of the catchment boundaries to be applied to identify the HEP catchments. If it is decided that adjustments have to be made to the automatic boundaries, then it is important that these adjustments are made consistently, i.e. that boundaries are correctly nested and that neighbouring catchments share one boundary. The manually adjusted (FSU) boundary dataset does not satisfy that requirement.

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6 Review of Meteorological Data

6.1 Introduction

Rainfall analysis has focussed on the daily rainfall data provided to Jacobs by Met Éireann, either through a direct data request or via the OPW (refer to Table 3-B). As a result of missing data, daily raingauge 6205 has been excluded from this phase of the study.

6.2 Distribution of raingauges within Shannon Estuary South

Daily read raingauges are not evenly distributed across the Shannon Estuary South (ref. Figure 4). Their distribution is clustered in the northern portion of the unit of management, and primarily within the lower reaches of the Deel and Maigue catchments. Three raingauges are located outside and to the west of these catchments, one each in the River Robertstown and River White catchments and one located on Tarbert Island.

6.3 Data review

To obtain some understanding of the completeness of the rainfall record and its long-term consistency, a brief review was undertaken on receipt of the data. Firstly, the number of missing days was counted. Subsequently, data for similar periods from adjacent stations were plotted against each other on double mass plots to highlight any obvious inconsistencies in the records.

A count of missing data reveals that gauges 4611 (Tarbert Island) and 5811 (Meanus) have large portions of missing data, 22% and 33% respectively (Table 6- A). Stations 4811 (Patrickswell), 6111 (Shanagolden) and 6311 (Ballyhahill) have either no or minimal missing data.

Total % of Raingauge Record Record Missing Name number data no. start end days of days missing

4611 Tarbert Island 13/02/1968 30/11/2009 15267 3310 22 4811 Patrickswell 01/09/1981 31/05/2010 10500 9 0 4911 Castlemahon 01/04/1982 31/12/2009 10137 68 1 Rathkeale 5111 Duxtown 01/07/1984 31/12/2009 9315 316 3 Newcastle 5711 West 08/02/1992 31/12/2009 6537 135 2 5811 Meanus 01/06/1993 31/10/2004 3955 1318 33 6111 Shanagolden 01/07/1994 31/05/2010 5814 3 0 6311 Ballyhahil 01/01/2001 31/12/2009 3287 0 0 Table 6-A Summary of rainfall data, period of record and missing days

Double mass plots were created to ensure each raingauge was reviewed at least once (ref. Appendix B for plots). In general the plots confirmed that long term rainfall relationships between raingauges were fairly consistent across the catchment. However, it did serve to highlight the scale of missing data from record TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc FINAL 41 of 100

5811 and a potential change at raingauge 5711. When the cumulative record for 5711 was plotted against cumulative rainfall from stations 4911 and 6311 both plots revealed a change in the relationship in around May or June 2005. There is no scope for further investigation at this stage of the study; therefore out of caution, rainfall from station 5711 is assumed to be excluded from further use in this study. However, if there is merit in using the data post-2005, this will be considered.

Cumulative totals for all raingauges between 1 January 2001 and 29 March 2004 indicate geographical variations in rainfall received throughout the unit of management with higher medium-term rainfall totals in the west of Shannon Estuary South compared to the east (Table 6-B). The raingauge recording the highest total rainfall was 6311 at Ballyhahill with a total of 4101.0 mm for that period.

Station No. Cumulative total rainfall (mm) 4611 3085.8 4811 2685.5 4911 2839.9 5111 3801.1 5711 3395.6 5811 2237.6 6111 3257.4 6311 4101.0 Table 6-B Cumulative rainfall for stations in Shannon Estuary South between 1 January 2001 and 29 March 2004.

6.4 Raingauge selection

Following the data review a selection of raingauges were chosen for further analysis, in which depth, duration and frequency estimates derived from local data were compared with the theoretical values derived for the FSU. Due to the close proximity of the raingauges within the unit of management, it was not deemed necessary to review all raingauge data.

The following raingauges were selected based on location, completeness of data and quality of record:

. 4611 – Tarbert Island . 4811 – Patrickswell . 5111 – Rathkeale Duxtown

Despite the high proportion of missing data, raingauge 4611 was included primarily due to its location as the furthest westerly raingauge in the area. A review of the time series identified that the majority of missing data was prior to 1993 and even excluding this data, the time series was still longer than the closest gauge, 6311 whose record commences 1 January 2001.

Raingauge 4611 is located on Tarbert Island within the ‘Other’ sub-catchment, as defined by this study to include catchments outside of the Maigue and Deel, whilst 4811 and 5111 are located in the Maigue and Deel sub-catchments respectively and collectively provide the best possible coverage across the unit of management.

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6.5 Rainfall probability plots

For the three raingauges selected in Section 6.4, a 1-day total annual maxima and a 4-day total annual maxima series were created. Any years with more than 30 days of missing data were excluded and this left 4611, 4811, and 5111 with 16, 30 and 21 years of data respectively.

The annual maxima series were ranked in decreasing order of magnitude. The probability of exceedance was derived according to Gringorten, where P(X) is the probability of exceedance and is calculated for each value of X, r is the rank and N is the total number of annual maxima values.

r − 0.44 P(X ) = (6.1) N + 0.12

The EV1 distribution was fitted to the observed annual maxima series of rainfall totals using the method of moments described in formulas 6.2 – 6.4 below, where F(X) is the probability of an annual maximum Q ≤ X and a and b are parameters with μ σ Q being the mean and Q the variance.

F(x) = exp[− e −b( X −a ) ] (6.2)

γ = μ − (6.3) a Q b π b = (6.4) σ Q 6

The subsequent distribution fits (Appendix C) were used to derive estimates of annual exceedance probability for historic events to ensure a coherent relationship between estimates. However, note that the annual exceedance probabilities can also be estimated directly from the plotted local data. Therefore, the actual fit with the chosen distribution has little relevance for this independent check of the FSU DDF method.

6.6 Events of interest

Severe rainfall events were identified in conjunction with the annual maxima flow series. The three rainfall stations identified in 6.4 will be the focus for the analysis. For consistency the same events selected for fluvial analysis will be reviewed here also. Event selection is detailed in Sections 7.6 and 7.7. The five events selected are:

. 11 – 12 October 1988; . 29 - 30 December 1998; . 6 - 7 November 2000; . 31 July – 1 August 2008; . 31 January - 1 February 2009.

For each event the maximum depth of rainfall for a range of durations; 1 day, 2 days, 4 days and 10 days were obtained. Depths for each duration were produced TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc FINAL 43 of 100

by summing the daily rainfall total for the corresponding x number of preceding days. Maximum values were selected from within a 10 day period up to and including the date of the largest peak flow within the catchment. The results are presented below in Sections 6.6.1 to 6.6.5 inclusive.

To put the rainfall depths into context annual exceedance probabilities were derived for the 1 day and 4 day rainfall totals based on the probability plots outlined in Section 6.5.

It is important to note that the availability of daily rainfall only is anticipated to significantly increase the uncertainty in respect of the analysis of rainfall events with sub-daily durations.

6.6.1 Event of 11 - 12 October 1988

High fluvial flows recorded on 11th and 12th October appear to have been the result of a high intensity and short duration rainfall event on 10th October, with daily rainfall totals of between 25.3 mm and 39.7 mm recorded at the selected raingauges. A plot of the daily rainfall for the 10 days preceding the event (Figure 11) indicates a period of prolonged rainfall, which is likely to have saturated the catchments. Daily rainfall totals were generally higher at raingauges 4811 and 5111.

45

4611 40 4811

35 5111

30

25

20 Rainfall (mm)

15

10

5

0

8 8 8 8 8 8 8 8 8 8 8 98 98 1 /198 /19 1 /10 /10 03/10/198 04/10/198 05/10/ 06 07 08/10/198 09/10/198 10/10/198 11/10/ 12/10/198

Figure 11 Daily rainfall – 3rd October to 12th October 2011 (NB: rainfall missing at 4611 on 8th October 1988) Annual exceedance probabilities (AEPs) for the maximum rainfalls over the event are presented in Table 6-C. AEPs estimated from the 1-day and 4-day rainfall probability plots indicate this was in general a rarer event for the 1 day duration compared to the longer 4-day duration. Values derived for the 1 day duration at raingauges 4811 and 5111 indicate that this event has annual exceedance probability of 16% and 22% respectively

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Oct-88 4611 4811 5111 Rainfall 4611 Rainfall 4811 Rainfall 5111 depth AEP depth AEP depth AEP Rainfall Duration (mm) (%) (mm) (%) (mm) (%) 1 day rainfall (mm) 25.3 89 39.7 16 39.5 22 2 day rainfall (mm) 37.3 43.8 44.4 4 day rainfall (mm) 43.4 90 49.3 55 54.7 55 10 day rainfall (mm) 85.9 85.8 104.4 Table 6-C Maximum rainfall depths for 1 day, 2 day, 4 day and 10 day durations with corresponding AEP for 1 day and 4 day durations (October 1988)

6.6.2 Event of 29 - 30 December 1998

A review of the daily rainfall plotted in Figure 12 suggests that peak flows on both the River Maigue and River Deel were triggered by a rainfall event on 29th December 1998, following a period of prolonged lighter rainfall across the catchment. For the 10 days preceding the 31 December all three gauges recorded at least 7 out of 10 days with total daily rainfall exceeding 5mm.

30 4611 4811

25 5111

20

15 Rainfall (mm) Rainfall

10

5

0 21/12/1998 22/12/1998 23/12/1998 24/12/1998 25/12/1998 26/12/1998 27/12/1998 28/12/1998 29/12/1998 30/12/1998

Figure 12 Daily rainfall – 21st December to 30th December 1998

Annual exceedance probabilities (AEPs) for the maximum rainfalls over the event are presented in Table 6-D. AEPs estimated for the maximum event rainfall at raingauges 4611, 4811 and 5111 indicate that for both the 1 day and 4 day durations this is a typical annual event. Only the AEP value for the 4 day rainfall total recorded at 5111 indicates a probability slight lower.

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Dec-98 4611 4811 5111 Rainfall 4611 Rainfall 4811 Rainfall 5111 depth AEP depth AEP depth AEP Rainfall Duration (mm) (%) (mm) (%) (mm) (%) 1 day rainfall (mm) 15 100 14.6 99 24.2 84 2 day rainfall (mm) 21.6 21.9 38.2 4 day rainfall (mm) 40.3 100 30.2 97 49.8 67 10 day rainfall (mm) 63 59.9 72.1 Table 6-D Maximum rainfall depths for 1 day, 2 day, 4 day and 10 day durations with corresponding AEP for 1 day and 4 day durations (December 1998)

6.6.3 Event of 6 - 7 November 2000

Daily rainfall of between 19.8 mm and 28.7 mm on 5th November following a period of prolonged low intensity rainfall (ref. Figure 13) across the area appear to be the origin of the high flows. The duration and widespread nature of the rainfall are consistent with a prolonged winter depression.

35

4611 4811 30 5111

25

20

15 Rainfall (mm) Rainfall

10

5

0 28/10/2000 29/10/2000 30/10/2000 31/10/2000 01/11/2000 02/11/2000 03/11/2000 04/11/2000 05/11/2000 06/11/2000

Figure 13 Daily rainfall – 28th October 6th November 2000

Annual exceedance probabilities (AEPs) for the maximum rainfalls over the event are presented in Table 6-E. Estimated AEPs indicate that this was a less frequent event for the 4-day duration as opposed to the 1-day duration rainfall, not surprising considering the nature of the event and highlighting the influence of antecedent rainfall on the catchment response. However, AEP estimates still associate it within the bounds of a typical annual event.

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Nov-00 4611 4811 5111 Rainfall Rainfall 4811 Rainfall 5111 depth 4611 depth AEP depth AEP Rainfall Duration (mm) AEP (%) (mm) (%) (mm) (%) 1 day rainfall (mm) 23 94 19.8 92 28.7 64 2 day rainfall (mm) 29 24.5 34.7 4 day rainfall (mm) 57.8 64 45.1 66 59.4 45 10 day rainfall (mm) 97 76.7 105.2 Table 6-E Maximum rainfall depths for 1 day, 2 day, 4 day and 10 day durations with corresponding AEP for 1 day and 4 day durations (November 2000)

6.6.4 Event of 31 July – 1 August 2008

Daily rainfall presented in Figure 14 reflects a short duration, high intensity rainfall event, consistent with a summer convective storm. Rainfall totals peak on the 31 July with 48.4 mm recorded at 4811 within the lower reaches of the Maigue catchment. A lower daily rainfall total of 29.3 mm is recorded at 4611, however, the preceding day a total of 37.4 mm of rain was recorded which this suggests that the storm event may have spanned 09:00 hours, when the raingauge is read and emptied daily.

60

4611 4811

50 5111

40

30 Rainfall (mm)

20

10

0 24/07/2008 25/07/2008 26/07/2008 27/07/2008 28/07/2008 29/07/2008 30/07/2008 31/07/2008 01/08/2008 02/08/2008

Figure 14 Daily rainfall – 24th July to 2nd August 2008

Annual exceedance probabilities (AEPs) for the maximum rainfalls over the event are presented in Table 6-F. Estimated AEPs indicate that the 1 day rainfall depth as recorded at 4811 was a relatively rare event with an AEP of 4%. If it is considered that the event spanned the 09:00 threshold of the raingauge being read and the daily rainfall recorded for 30th and 31st July would have been recorded in a 24-hour period, the revised AEP is 5%, similar to that of 4811.

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Jul-08 4611 4811 5111 Rainfall Rainfall Rainfall 5111 depth 4611 depth 4811 depth AEP Rainfall Duration (mm) AEP (%) (mm) AEP (%) (mm) (%) 1 day rainfall (mm) 34.7 60 48.4 4 38.4 25 2 day rainfall (mm) 64 51.8 49.4 4 day rainfall (mm) 65.2 49 69.2 16 63.6 37 10 day rainfall (mm) 65.2 73.6 75.6 Table 6-F Maximum rainfall depths for 1 day, 2 day, 4 day and 10 day durations with corresponding AEP for 1 day and 4 day durations (August 2008)

6.6.5 Event of 31 January - 1 February 2009

Daily rainfall ploted in Figure 15 for the period 22nd January to 31st January 2009, illustrates some variation in rainfall depths across the area. At raingauges 4811 and 5111 a period of fairly steady rainfall, peaking on 30 January is noted, whilst the rainfall at 4611 appears more intermittent.

30 4611 4811 5111 25

20

15 Rainfall (mm) Rainfall

10

5

0 22/01/2009 23/01/2009 24/01/2009 25/01/2009 26/01/2009 27/01/2009 28/01/2009 29/01/2009 30/01/2009 31/01/2009

Figure 15 Daily rainfall – 22nd January to 31st January 2009

Table 6-G presents the AEPs estimated for the daily and 4-day durations. The figures for raingauges 4611 and 5111 suggest that it was a typical annual event. The AEP estimates for 4811 only indicate that the event occurs slightly more frequently than on an annual basis.

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Jan-09 4611 4811 5111 4611 4811 5111 Rainfall Rainfall Rainfall Rainfall Duration AEP (%) AEP (%) AEP (%) depth depth depth

(mm) (mm) (mm) 1 day rainfall (mm) 16 99 26.6 63 13.3 100 2 day rainfall (mm) 23.5 32.9 23.5 4 day rainfall (mm) 40.3 94 34.4 91 26.2 99 10 day rainfall (mm) 98.8 66.2 77.2 Table 6-G Maximum rainfall depths for 1 day, 2 day, 4 day and 10 day durations with corresponding AEP for 1 day and 4 day durations (January 2009)

6.7 Flood Studies Update rainfall comparison

Theoretical point rainfall depths, created for the Flood Studies Update were extracted from GIS raster layers for a range of Annual Exceedance Probabilities between 50% and 0.5% at the 24 hour and 4 day durations. GIS rasters were not available for the 10 day duration rainfall. Output values are presented in Table 6-H.

Annual 4811 4911 5111 Return Period Exceedance Rainfall Rainfall Rainfall Duration (years) Probability Depths Depths Depths (%) (mm) (mm) (mm) 24 hour 2 50 34.3 37.9 37.3 24 hour 5 20 47.3 47.2 50.6 24 hour 10 10 57.1 53.7 60.5 24 hour 20 5 67.9 60.4 71.3 24 hour 30 3 74.9 64.6 78.3 24 hour 50 2 84.6 70.2 87.9 24 hour 100 1 99.7 78.5 102.6 24 hour 200 0.5 117.3 87.7 119.6 4 day 2 50 54.0 68.0 63.5 4 day 5 20 70.4 80.6 80.9 4 day 10 10 82.4 88.9 93.2 4 day 20 5 95.1 97.4 106.2 4 day 30 3 103.1 102.6 114.4 4 day 50 2 114.0 109.3 125.4 4 day 100 1 130.6 119.1 141.8 4 day 200 0.5 149.3 129.7 160.3

Table 6-H Rainfall depths for a range of frequencies and two durations obtained from grids corresponding to the locations of raingauges 4811, 4911 and 5111. As stated previously, comparison of daily rainfall data and 24 hour data may not be a precise or even fair comparison due to the possible underestimation of maximum daily rainfall values should an event straddle 09:00 hours.

Depth, duration and frequency estimates derived from local data were compared with the theoretical values derived for the FSU (ref. Section 3.7.1). To assist, FSU rainfall depths for varying durations were plotted against Annual Exceedance Probabilities between 50% and 0.5% (ref. Appendix D). The resulting plots were used to estimate the FSU AEP of the actual rainfall depths. Results of this analysis are presented for each raingauge below (Tables 6-I, J and K), with the FSU estimates of equal or less than 50% highlighted in bold for ease of reading.

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]4611 1 day 4 day

Maximum FSU AEP Maximum Estimated Event Estimated FSU AEP depth (%) depth AEP (%) date AEP (%) (%) (mm) (approx) (mm) (approx)

Oct-88 25.3 89 > 50 43.4 90 > 50 Dec-98 15 100 > 50 40.3 100 > 50 Nov-00 23 94 > 50 57.8 64 42 Jul-98 34.7 60 50 65.2 49 29 Jan-99 16 99 > 50 40.3 94 > 50 Table 6-I 1 day and 4 day rainfall and associated Annual Exceedance Probability (AEP) for raingauge 4611

4811 1 day 4 day

Maximum FSU AEP Maximum Estimated Event Estimated FSU AEP depth (%) depth AEP (%) date AEP (%) (%) (mm) (approx) (mm) (approx)

Oct-88 39.7 16 43 49.3 55 > 50 Dec-98 14.6 99 > 50 30.2 97 > 50 Nov-00 19.8 92 > 50 45.1 66 > 50 Jul-98 48.4 4 16 69.2 16 47 Jan-99 26.6 63 > 50 34.4 91 > 50 Table 6-J 1 day and 4 day rainfall and associated Annual Exceedance Probability (AEP) for raingauge 4811

5111 1 day 4 day

Maximum FSU AEP Maximum Estimated Event Estimated FSU AEP depth (%) depth AEP (%) date AEP (%) (%) (mm) (approx) (mm) (approx)

Oct-88 39.5 22 46 54.7 55 > 50 Dec-98 24.2 84 > 50 49.8 67 > 50 Nov-00 28.7 64 > 50 59.4 45 > 50 Jul-08 38.4 25 48 63.6 37 50 Jan-09 13.3 100 > 50 26.2 99 > 50 Table 6-K 1 day and 4 day rainfall and associated Annual Exceedance Probability (AEP) for raingauge 5111

As expected there is some difference between the two estimates of AEP for the same rainfall depth and duration. The majority of rainfall depths fell above 50% AEP and therefore appear broadly to agree with the estimated AEP derived from the data.

For the three rainfall depths which fell below the 50% FSU AEP threshold on raingauge 4611 (Tarbert Island), the FSU AEP estimates were consistently lower than those derived from the actual data, suggesting that the events were rarer than estimated from actual data.

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At raingauges 4811 and 5111, the opposite was observed, whereby the FSU AEP estimates were consistently higher than the estimates obtained from actual data. This is most notable for the July 1998 event at raingauge 4811, where the AEP estimated from the data was 4% compared to 16% estimated by FSU methods. This is a considerable disparity.

Comparing the FSU estimated depths and frequencies with the plotted historical local data as presented in the graphs in Appendix C shows that the FSU DDF estimates do not appear to accurately reflect the local conditions at the three rainfall stations considered here.

One contributory factor to the discrepancy may be the use of fixed-duration rainfall (09:00-09:00 UTC data) rather than the sliding-duration used or adjusted for by the FSU (2007). For 1-day duration data this can lead to an underestimation of fixed- duration rainfall by up to 13%. This effect diminishes with increasing duration. It would appear that this contribution alone cannot explain the entire discrepancy.

6.8 Conclusions

Nine Met Éireann daily storage raingauges have been identified within the Shannon Estuary South Unit of Management, however, data was only provided for eight. No sub-daily rainfall data was available and this has limited the rainfall durations analysed and the conclusions that were able to be drawn.

Rainfall depths calculated for four durations, 1-day, 2-day, 4-day and 10-day, suggest that events were the result of both winter depressions, characterised by a moderately intense rainfall event preceded by prolonged rainfall, and a summer convective event characterised by high intensity short duration rainfall.

Annual exceedance probabilities for the 1 day and 4 day duration rainfall depths were estimated based on probability plots developed from annual maxima series derived from the rainfall record.

Subsequent annual exceedance probabilities estimated indicate that the majority of rainfall events were typical annual events with an AEP of 50% or greater. The lowest annual exceedance probability estimated was 4% for a 1 day rainfall depth at station 4811 during the July 2008 event.

Annual exceedance probabilities estimated from actual data for the 1 day and 4 day durations and compared to theoretical AEPs for the 24 hour and 4 day durations created for the Flood Studies Update varied. FSU AEPs were lower AEPs at station 4611 and higher AEPs at stations 4811 and 5111. These differences appear to suggest that the FSU DDF estimates do not accurately reflect the DDF relationship at the three rainfall stations considered.

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7 Review of Fluvial Data

7.1 Introduction

Those gauging stations located within the Shannon Estuary South Unit of Management (UoM 24) and for which any instantaneous, daily mean or annual maxima (AMAX) flow or level data was received are listed previously (Tables 3-A, 3- C and 3-F). The subsequent review and analysis of fluvial data has been limited to these stations.

As outlined previously, the majority of flow and level gauges within the Shannon Estuary South Unit of Management are located on the Rivers Maigue and Deel and their tributaries. Of the 24 stations for which some fluvial flow and level data were provided, 12 stations are located within the River Maigue catchment down to its tidal limit, 9 within the River Deel catchment, and 1 each on the Robertstown, White and Greanagh rivers. To assist in the review of catchment response the unit of management has been divided into the following sub-catchments, the Deel, the Maigue and ‘Others’ (ref. Figure 16).

The Shannon CFRAM study is primarily concerned with flooding, therefore good quality high flow and level data are required. The objective of this data review is to assemble the fluvial data available and understand its suitability for the use in the CFRAM study.

Not all the data requested was issued promptly and a cut off date was required to ensure completion of the preliminary review. A cut off of 21 June 2011 was selected and any data received after this date will be acknowledged but excluded from any review or analysis presented in this report.

7.2 Distribution of flow and level gauging stations within UoM 24

Within the Maigue catchment, five hydrometric gauging stations are located on the River Maigue (24004, 24001, 24082, 24008 and 24000), three on the River Loobagh (24034, 24016 and 24003) and one each on the Rivers Camoge (24002), Morningstar (24005) and Mahore (24022). This distribution ensures that all significant tributaries are gauged in at least one location. There is some clustering of flow gauges along the River Maigue in the lower reaches, downstream of the last major tributary (River Camoge) where the river is gauged in three locations. The River Maigue can be considered tidal from Adare Quay.

There are nine gauging stations located within the Deel catchment, six are located on the River Deel (24030, 24011, 24100, 24012, 24013 and 24029), and are fairly evenly distributed spatially along its length. The Ahavarragh Stream (24015) and Rivers Bunoke (24045) and Finglosha (24046) are each gauged at one location. No data is currently available for recently installed gauges on the watercourses which drain the steep topography of the Knockanimpaha mountain area to the west of Newcastle West.

Outside of the Deel and Maigue catchments in the ‘Others’ catchment, the River Greanagh is gauged at Normoyle’s Bridge (24067) and discharges into the tidal River Maigue. Two further gauges are located on the Robertstown and White Rivers (24017 and 24033 respectively) located to the west of the Deel catchment,

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each draining a small catchment which discharges directly into the Shannon Estuary at the Robertstown inlet.

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90000 100000 110000 120000 130000 140000 150000 160000 170000 180000 160000 160000

Clarina Kildimo New B a akyle ll Foynes arn (R yn B ive ac r) lo gh Askeaton 24061 (R Shannon Estuary 24017 i Tarbert Power Station ve 24029 r) G lash A 150000 150000 anagar k (Riv h er) a c r o 24062 Adare n a lashanaskee (River) n 24067 M G e a i 24009 ) W ( g Ballylongford r R e h u i e iv t iv e e ( R 24033 24008 R ( ( r ) ly R b i iv r v n e o r) c e r u en ) a l d 24013 Croom r) G o e r iv t Rathkeale R Ballyl iv er) a ( in e (R 24002 e K h g i s a g 24082 o s ) r m e a i v 24001 C l (R namona (R 140000 y iv 140000 ee all e r ) D B Da tre ) ar (S a m (R S le aun 24022 iv w n e r ) er) 24012 (Riv D r) M re o 24005 e o a iv a h l 24100 (R l y r Newcastle West ta ( s Arra (Rive R M ing r) iver) o rn 24011 w ka s ) n 24004 B e ally m w B an o a O i ) e a ream g r 24030 ( St (R t iv S e ( r) 130000 130000 h g Kilmallock a n 24046 24006 er Eh ) Lo ver ob 24034 (Ri 24016 a ha gh 24045 s ( Bun Fing la 24003 Riv ok er) e (R r) iv Rive er ) n ( ) r Barrana how e Charleville iv

R ( 24015 r) h Dromcolliher n (Riv e g G le Kill il a

) r 120000 120000 e iv a ( R Mullaheer

Legend

River Network Community at Risk (CAR) Estuary Subcatchments Individual Risk Receptor (IRR) Maigue (24009)

Deel (24029) Active Hydrometric Station 110000 110000 Other

Inactive Hydrometric Station

Project No. 32103000

Project Titl e Shannon CFRAMS Study

Drawing Title Subcatchments Unit of Management 24 100000 100000

0204010 Kilometres

90000 100000 110000 120000 130000 140000 150000 160000 170000 180000 Figure 16 Shannon Estuary South Unit of Management with the Maigue, Deel and Other sub-catchments delineated

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7.3 Data review

It was assumed that data was provided by the OPW or EPA quality assured. In order to gain an understanding of the completeness and the quality of data at each gauged location, flows and level records were reviewed upon receipt of the data. This assessment was aimed at providing an overview of the quality of data based on a visual inspection of daily mean flow (or level) records, a count of quality codes (where available), completeness of record and any long-term trends which may impact on the confidence given to QMED. Daily mean flows were inspected in preference to instantaneous data to focus the review on gross errors and long-term trends. A summary of the review findings can be found in Table 7-A, whilst a more detailed summary is documented in Appendix E.

All 12 daily mean flow and / or level records available were visually reviewed (ref. Table 3-D). Only three stations were identified as not having any obvious trends or consistencies, whilst 8 stations (24001, 24003, 24005, 24008, 24011, 24012, 24013 and 24082) indicated trends of rising levels and/or flows over the period of record. In some of the records (24001, 24003 and 24011), a trend was evident in the level series but not in the flow, which suggests a change to the gauged cross-section possibly accounted for in the flow record by a revision of the rating. Trends in peak flows, either rising or declining are problematic as they disprove the assumption of homogeneity of a flow series; an assumption routinely made when undertaking any hydrological statistical analysis.

An example of a typical observed trend in peak flows is shown in Figure 16a below.

180

160

140

120

100

80 Flow (cumecs)

60

40

20

0

01/11/1977 01/11/1978 01/11/1979 01/11/1980 01/11/1981 01/11/1982 01/11/1983 01/11/1984 01/11/1985 01/11/1986 01/11/1987 01/11/1988 01/11/1989 01/11/1990 01/11/1991 01/11/1992 01/11/1993 01/11/1994 01/11/1995 01/11/1996 01/11/1997 01/11/1998 01/11/1999 01/11/2000 Figure 16a Example of trend at station 24082

It is possible that the trends are indicative of climatological trends rather than site specific, although an analysis of the long term rainfall time series did not identify any such trends. Further investigation by OPW into the flow and level series is recommended to determine whether this is actually the case. Land use change is another potential contributing factor although this has not been considered in detail in this Preliminary Hydrological Assessment.

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Daily Flow data only Daily Level data only % of poor UoM 24 % of or % of Total % of % of % of Total Further Station sub- FSU good cautionary missing number good cautionary missing number investigation no. Station name River catchment Class days days days of days days days days of days recommended Yes - trend in 24001 Croom Maigue Maigue A2 38 7 4 13858 96 0 4 13858 water level, flows ok 24002 Gray's Bridge Camoge Maigue A2/B 92 0 4 9044 No Yes - rising trend 24003 Garroose Loobagh Maigue 83 0 16 13859 83 0 16 13859 in water level, flows ok 24004 Bruree Maigue Maigue B 69 1 6 11414 87 0 6 11810 No

Yes - rising trend 24005 Athlacca Morningstar Maigue 45 0 51 16761 in water level

Yes - 24006 Creggane Maigue Maigue 21 0 78 13859 irregularities in water level Yes - trend in 24008 Castleroberts Maigue Maigue A2 70 1 5 12939 89 0 3 13436 water level, flow ok. Yes - trend in 24011 Deel Bridge Deel Deel B 2 16 4 5477 97 0 1 7923 water level, flow ok

Yes - trend of 24012 Grange Bridge Deel Deel B 24 27 5 19177 97 0 3 19174 increasing flows

Yes - trend of 24013 Rathekeale Deel Deel A1 0 12 8 13859 94 0 5 13858 increasing flows

Riversfield 24034 Loobagh Maigue 61 4 7 2248 89 1 7 2259 No Weir Yes - trend of 24082 Islandmore Maigue Maigue A2 2 0 2 8513 98 0 2 8513 increasing peak flows

Table 7-A Summary of daily mean flow and level data review (see also Appendix E) (grey squares indicate no data)

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Sudden and anomalous dips in water level were observed in two of the records, 24003 and 24008. Typically such anomalous values are removed from the record and will be excluded should they arise within further event analysis.

Analysis of the OPW quality codes (ref. Table 3-E) assigned to the data revealed that at two sites, 24011 and 24082 only 2% of the daily flow series was considered to be of ‘good’ quality. One station, 24012, had 27% of the daily flow series data flagged as poor or cautionary.

Two daily level series had greater than 50% of the data series flagged as missing, these were stations 24005 (51%) and 24006 (78%). This percentage of missing data can greatly reduce the utility of a data series.

For locations where both flow and level data was available it was apparent that quality codes for the same site were, in general, not equivalent. This can partly be attributed to the differing classifications for flow and level series, but even where classifications were the same the counts for each were often dissimilar.

7.4 Annual maxima flow and level series

Annual maxima (AMAX) data for the 16 fluvial stations in UoM 24 (excluding the short record of 24100) (ref. Table 3-F) were ranked to identify the top 5 and top 10 ranked events for each gauging station. In Table 7-B, the top 5 events at each location are identified by the letter A and yellow shading; those ranked 6-10 are identified by the letter ‘B’ and green shading. Due to the manual extraction of selected peak flows the rank of flow and level for a given event could differ at the same location. Therefore, where both flow and level annual maxima series were available, the flow series was used in preference. The subsequent matrix of annual maxima provided an overview of the most significant events across the catchment (Table 7-B). It is worth noting, however, that both the period of record and length of an annual maxima series can skew the data and therefore should be used as one of a series of approaches for assessing severe events.

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Hydrometric Gauging Station Dates Maigue Deel 24001 24002 24003 24004 24005 24006 24008 24009 24022 24034 24082 24011 24012 24013 24030 27-Feb-1954 B 01-Jan-1955 B 3-4 Dec 1960 B 20-Mar-1964 A 17-Jan-1965 A 17-Nov-1965 B 10-Dec-1965 A 23-Feb-1967 A 18-Oct-1967 B 02-Nov-1968 A 15-Dec-1968 A 10-Jan-1969 A 20-Jan-1970 B 07-Dec-1972 A 1-3 Dec 1973 A A A A A 27-30 Jan 1975 A 30 Jan - 1 Feb 1976 B B 19-Feb-1977 B 02-Nov-1980 A B A A 22-May-1981 B 08-Nov-1982 A A 31-Jan-1983 B B 16-Dec-1983 A A A B B B A 06-Aug-1986 A B B B B A B A 08-Dec-1986 B 01-Feb-1988 A 11-12 Oct 1988 B A B A A A 21-22 Oct 1988 A A A A A A A 6-7 Feb 1990 B A A A A A B A A B B 15- 16 Jan 1994 B B B 19-Feb-1994 B 25-26 Jan 1995 A B B 22-23 Feb 1995 A A A 9-10 Mar 1995 B A B A

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Hydrometric Gauging Station Dates Maigue Deel 24001 24002 24003 24004 24005 24006 24008 24009 24022 24034 24082 24011 24012 24013 24030 24-Nov-1995 B B 28-Oct-1996 B 05-Aug-1997 B A B B A B B 17-18 Oct 1997 B 29-30 Dec 1998 B A A A A A A B A B A B 18-Dec-1999 B 24-25 Dec 1999 A 6-7 Nov 2000 B B B A B A A B 26-Nov-2000 B 30-Nov-2000 B 21-23 Jan 2002 B B 01-Feb-2002 B 26-Feb-2002 A 27-Nov-2002 B B 14-Nov-2003 B B 27-29 Oct 2004 A A A B 28-Nov-2004 A 08-Jan-2005 A 20-Feb-2006 B 22-May-2006 B 01-Jan-2008 B 10-Jan-2008 B B 10-Mar-2008 31 Jul- 1 Aug 2008 A A 10-Oct-2008 B A 31 Jan -1 Feb 2009 B B B 01-Nov-2009 B 14-Nov-2009 20-Nov-2009 A Table 7-B Top 5 (A) and Top 6-10 (B) AMAX flow or level for hydrometric gauging stations within UoM 24.

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7.5 Flow and level flood frequency curves

Where an AMAX series was available for a continuous flow series with a period of record greater than 10 years a flood frequency plot was developed. Research documented in FSU guidance (Work package 2.2) concluded that no single distribution could be considered a ‘best fit’ to all locations across Ireland. However, it was reported that the use of either a lognormal or Extreme Value Type 1 (EV1 or Gumbel) distribution provided a reasonable fit for the majority of stations.

Based upon this recommendation and for the benefit of consistency, one distribution will be selected as the distribution to be fitted to all applicable AMAX series in this Inception reporting phase of the study. The most likely candidates for this distribution are the lognormal and EV1 distributions. The selection of the distribution will be carried out after completion of the rating review process when the reliability of the available AMAX data has been assessed and possibly improved.

As part of this preliminary hydrological analysis flood frequency curves were developed following the procedure outlined in Section 6.5 based on an EV1 distribution and plotted according to Gringorten.

The subsequent flood frequency curve was used to derive estimates of annual exceedance probability for historical events rather than from data directly to ensure a coherent relationship between estimates.

Flood frequency plots were derived for 15 hydrometric gauging stations located in the Shannon Estuary South Unit of Management for which an AMAX series greater than 10 years was available.

The flood frequency plots can be found in Appendix F and on the Gauging Station Summary Sheets in Appendix H. The reasons for the shapes of the plots and the locations of any outliers, or extended “flat” rating curves, will be given due consideration following the completion of the gauging station reviews and the re- working of the AMAX series as necessary, recognising that an unusual shape can be a result of physical reasons, data limitations, or simply the statistical distribution of floods that has occurred over the data record.

7.6 Event analysis

For each gauged sub-catchment, three flood events have been selected and will form the basis of a detailed hydrological analysis of hydrograph shape, duration, volume of flow, runoff and estimated probability of the event.

Events were selected based a review of the AMAX series from gauges across the catchment (ref. Table 7-B) in conjunction with the occurrence of historical flood events as documented on the floodmaps.ie website. Emphasis has been placed on the selection of events which have occurred in the past 15 years primarily to increase the chance of data availability.

It is expected that the comparison of three events is sufficient to derive the characteristic hydrograph shape. However, where three events do not give a consistent picture, additional events may be considered, provided there is data of appropriate quality that will significantly improve the analysis.

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7.7 Maigue catchment

The following events were selected to represent severe flood events within the Maigue catchment:

. 29 - 30 December 1998; . 6 - 7 November 2000; . 31 January - 1 February 2009.

The following gauging stations located across the catchment were selected to represent the catchment response:

24001 Maigue at Croom 24003 Loobagh at Garroose 24004 Maigue at Bruree 24005 Morningstar at Athlacca 24008 Maigue at Castleroberts 24082 Maigue at Islandmore

The catchment areas of gauges 24001 and 24082 differ only by 7.4 km2 but have both been included due to their differing hydrograph responses. A review of mean daily flow series (reported in Section 7.3) suggests that flows at station 24082 are suspect and flows at station 24001 appear reasonable.

7.7.1 Event of 29 - 30 December 1998

Flow data was extracted from the 15 minute series at four gauging stations between 29th December 1998 (00:00 hours) and 1st January 1999 (23:45 hours). Data was not available for station 24005 (Morningstar at Athlacca) and due to missing data (between 00:45 and 09:00 on 31st December 1998) at station 24082, it was also excluded. A summary of the data is presented in Table 7-C below.

Duration Peak (days, Station flow Time of peak Volume of hours, No. (m3/s) flow Start time End time flow (m3) minutes) 30/12/1998 29/12/1998 31/12/1998 24001 161.1 02:45 07:30 01:45 19,233,552 01:18:15 29/12/1998 29/12/1998 31/12/1998 24003 60.5 21:00 06:30 02:00 6,955,086 01:19:30 30/12/1998 29/12/1998 31/12/1998 24004 100.1 03:15 06:30 02:45 10,754,941 01:20:15

24005 30/12/1998 29/12/1998 31/12/1998 24008 166.7 06:45 07:45 03:15 19,078,823 01:19:30

24082 Table 7-C Summary of timings and flows for the flood event 29 - 30 December 1998 All four hydrographs (Figure 17 a) indicated a double-peaked event, with the first peak being the largest. Analysis has therefore focused on the first portion of the hydrograph ending at the start of the second rising limb of the hydrograph.

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Timing of the peak flows indicates that flows peaked first in the Loobagh tributary in the upstream reaches of the catchment and last on the Maigue at Castleroberts, the furthest downstream gauging station included in this analysis.

Based on the annual maximum flow series fitted with a Gumbel distribution as detailed in Section 7.5 annual exceedance probabilities were estimated for the event at each location. Results vary from 3% at the Maigue at Bruree (24004) to 17% on the Maigue at Croom. The 3% AEP estimated at Bruree suggests it was a relatively infrequent event.

Dec-98 Estimated Annual Station Station Peak flow Exceedance No. Name Watercourse (m3/s) Probability (%) 24001 Croom Maigue 161.1 17 24003 Garroose Loobagh 60.5 10 24004 Bruree Maigue 100.1 3 24005 Athlacca Morningstar 24008 Castleroberts Maigue 166.7 8 24082 Islandmore Maigue Table 7-D Estimated annual exceedance probabilities for peak flows during December 1998 event

7.7.2 Event of 6 - 7 November 2000

Instantaneous flow data was available at six gauging stations between 4th November 2000 (00:00 hours) and 10th November 2000 (23:45 hours). A summary of the data is presented in Table 7-E below.

Duration Peak (days, Station flow Time of Volume of hours, No. (m3/s) peak flow Start time End time flow (m3) minutes) 06/11/2000 05/11/2000 09/11/2000 24001 147.4 14:15 11:45 00:30 27,329,098 03:12:45 06/11/2000 05/11/2000 08/11/2000 24003 59.7 01:30 12:45 10:00 9,577,524 02:21:15 06/11/2000 05/11/2000 08/11/2000 24004 82.9 11:00 10:30 22:30 12,615,482 03:12:00 06/11/2000 05/11/2000 08/11/2000 24005 30.1 04:45 08:00 23:15 5,204,473 03:15:15 06/11/2000 05/11/2000 09/11/2000 24008 158.0 12:45 11:45 12:45 28,088,204 04:01:00 06/11/2000 05/11/2000 09/11/2000 24082 185.1 10:30 15:45 00:45 29,949,604 03:09:00 Table 7-E Summary of timings and flows for the flood event 6 – 7 November

All hydrographs (Figure 17 b) reflect the occurrence of a single event across the catchment.

Both the peak flow and the greatest volume of flow logged for the event was recorded at 24082 and exceeded the flows and volumes estimated just downstream at 24001 and 24008, casting some doubt on the 24082 record as flows at 24001 and 24008 appear consistent.

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The timing of peak flows in the lower catchment are also irregular considering there are no significant inflows between gauges 24082, 24001 and 24008, whereby the upstream gauge (24082) peaks first and the middle gauge (24001) peaks last.

Based on the annual maximum flow series fitted with a Gumbel distribution as detailed in Section 7.5 annual exceedance probabilities were estimated for the event at each location (ref. Table 7-F). Results vary from 3% on the Morningstar tributary at Athlaccaa (24005) to 85% on the adjacent tributary Loobagh at Garroose (24003). This disparity in adjacent tributaries suggests that high intensity rainfall may have been localised. In the lower reaches of the River Maigue, estimated AEPs are similar ranging between 8 % to 11% suggesting that in the lower reaches an event on this scale would be expected once in every 10 years.

7.7.3 Event of 6 - 7 November 2000

Instantaneous flow data was available at six gauging stations between 4th November 2000 (00:00 hours) and 10th November 2000 (23:45 hours). A summary of the data is presented in Table 7-E below.

Duration Peak (days, Station flow Time of Volume of hours, No. (m3/s) peak flow Start time End time flow (m3) minutes) 06/11/2000 05/11/2000 09/11/2000 24001 147.4 14:15 11:45 00:30 27,329,098 03:12:45 06/11/2000 05/11/2000 08/11/2000 24003 59.7 01:30 12:45 10:00 9,577,524 02:21:15 06/11/2000 05/11/2000 08/11/2000 24004 82.9 11:00 10:30 22:30 12,615,482 03:12:00 06/11/2000 05/11/2000 08/11/2000 24005 30.1 04:45 08:00 23:15 5,204,473 03:15:15 06/11/2000 05/11/2000 09/11/2000 24008 158.0 12:45 11:45 12:45 28,088,204 04:01:00 06/11/2000 05/11/2000 09/11/2000 24082 185.1 10:30 15:45 00:45 29,949,604 03:09:00 Table 7-F Summary of timings and flows for the flood event 6 – 7 November

All hydrographs (Figure 17 b) reflect the occurrence of a single event across the catchment.

Both the peak flow and the greatest volume of flow logged for the event was recorded at 24082 and exceeded the flows and volumes estimated just downstream at 24001 and 24008, casting some doubt on the 24082 record as flows at 24001 and 24008 appear consistent.

The timing of peak flows in the lower catchment are also irregular considering there are no significant inflows between gauges 24082, 24001 and 24008, whereby the upstream gauge (24082) peaks first and the middle gauge (24001) peaks last.

Based on the annual maximum flow series fitted with a Gumbel distribution as detailed in Section 7.5 annual exceedance probabilities were estimated for the event at each location (ref. Table 7-F). Results vary from 3% on the Morningstar tributary at Athlaccaa (24005) to 85% on the adjacent tributary Loobagh at Garroose (24003). This disparity in adjacent tributaries suggests that high intensity rainfall may have been localised. In the lower reaches of the River Maigue, estimated AEPs are

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similar ranging between 8 % to 11% suggesting that in the lower reaches an event on this scale would be expected once in every 10 years.

Nov-00 Estimated Annual Station Station Peak flow Watercourse Exceedance No. Name (m3/s) Probability (%) 24001 Croom Maigue 147.4 27 24003 Garroose Loobagh 59.7 85 24004 Bruree Maigue 82.9 10 24005 Athlacca Morningstar 30.1 3 24008 Castleroberts Maigue 158 11 24082 Islandmore Maigue 185.1 8 Table 7-G Estimated annual exceedance probabilities for peak flows during November 2000 event

7.7.4 Event of 31 January - 1 February 2009

Instantaneous flow data was available at six gauging stations between 29th January 2009 (00:00 hours) and 4th February 2009 (23:45 hours). A summary of the data is presented in Table 7-G below.

Duration Peak Station Time of Volume of (days, flow Start time End time 3 No. 3 peak flow flow (m ) hours, (m /s) minutes) 31/01/2009 29/01/2009 03/02/2009 24001 123.7 04:00 19:00 03:45 26,733,810 04:08:45 31/01/2009 29/01/2009 01/02/2009 24003 51.2 04:15 19:00 23:00 8,911,677 03:04:00 31/01/2009 29/01/2009 01/02/2009 24004 58.1 06:30 18:45 20:15 9,902,498 03:01:30 31/01/2009 29/01/2009 01/02/2009 24005 29.2 10:45 20:15 22:15 5,009,748 03:02:00 31/01/2009 29/01/2009 03/02/2009 24008 134.8 04:45 20:30 03:45 28,840,791 04:07:15 31/01/2009 29/01/2009 03/02/2009 24082 146.5 03:15 19:00 03:45 28,922,422 04:08:45 Table 7-H Summary of timings and flows for the flood event 31 January – 1 February 2009

Hydrographs (Figure 17 c) plotted for this event display a runoff response to more than one rainfall event. This is particularly evident on the Loobagh tributary at Garroose (24003) where three peaks can be identified, but is less evident further down the catchment and on the Morningstar tributary.

Timings of peak flow indicates that all gauges, with the exception of 24005 on the Morningstar tributary, peaked almost simultaneously suggesting a widespread rainfall event.

As noted for the November 2000 event, both the peak and volume of flow was greater on the Maigue at Islandmore (24082) when compared to the downstream gauges of 24008 and 24001.

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Annual exceedance probabilities estimated from the annual maximum flow series indicate that at Islandmore (24082) and Castleroberts (24008) on the lower River Maigue the event was of a similar probability of occurrence ~ 30%, but further downstream this value increases to around 50%.

Jan-09 Estimated Annual Station Station Peak flow Exceedance No. Name Watercourse (m3/s) Probability (%) 24001 Croom Maigue 123.7 53 24003 Garroose Loobagh 51.2 100 24004 Bruree Maigue 58.1 38 24005 Athlacca Morningstar 29.2 28 24008 Castleroberts Maigue 134.8 27 24082 Islandmore Maigue 146.5 31 Table 7-I Estimated annual exceedance probabilities for peak flows during January 2009 event

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180 24001 Croom 160 fgh 200 24003 Garroose 24001 Croom 24004 Bruree 180 24003 Garroose 24008 Castleroberts 140 24004 Bruree 160 24005 Athlacca 24008 Castleroberts 120 24082 Islandmore 140

100 120 80 100 Flow (cumecs) Flow

Flow (cumecs) 80 60 60 40

40 20 20 0 0 28/12/1998 29/12/1998 29/12/1998 30/12/1998 30/12/1998 31/12/1998 31/12/1998 01/01/1999 01/01/1999 02/01/1999 02/01/1 03-Nov-2000 04-Nov-2000 05-Nov-2000 06-Nov-2000 07-Nov-2000 08-Nov-2000 09-Nov-2000 10-Nov-2000 11-Nov-2000 12-Nov-2000 a) Event of 29 – 30 December 1998 b) Event of 6 – 7 November 2000 160 24001 Croom 140 24003 Garroose 24004 Bruree 24005 Athlacca 120 24008 Castleroberts 24082 Islandmore 100

80

Flow (cumecs) Flow 60

40 Figure 17 Hydrographs for the three events on the River Maigue 20

0 28/01/2009 29/01/2009 30/01/2009 31/01/2009 01/02/2009 02/02/2009 03/02/2009 04/02/2009 05/02/2

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7.7.5 Maigue catchment discussion

Of the three events reviewed, peak flow values were consistently the greatest in the December 1998 event (excluding 24082 for which there was no data available).

The hydrographs for all three events all indicate a steep rising limb and an initial steep recession which appears to flatten out. The shape of the hydrograph is indicative of a fast responding catchment.

Of the two gauged tributaries, the Loobagh and Morningstar, the Loobagh appears to consistently peak first. These tributaries drain adjacent areas and are of a similar size and the difference in time to peak can be attributed to the shape of their catchments, whereby the longer, narrower catchment of the Morningstar has a longer time-to-peak.

A feature of the hydrographs worthy of further investigation is the relationship between the peak flows at 24082, 24001 and 24008. The hydrographs indicate a consistent reduction in the peak flow and volume of flow between gauges 24082 and 24001 and 24008. Referring back to the review of daily data, the possibility of a trend of increasing peak flows was raised and this in conjunction with the inconsistent relationship between the gauges indicates an error is likely in the gauged data at 24082.

Further analysis of the catchment response in terms of the peak flow, volume of flow and runoff (Table 7-I) reveals that runoff for all three events is significantly greater at 24003 on the Loobagh tributary. This correlates with the steepest topography of the Maigue catchment, where the Loobagh drains the Ballyhoura Mountains. The Morningstar tributary (24005) which also drains the Ballyhoura Mountains has a lower runoff value, which suggests that a potentially higher runoff value in its upper reaches is diminished by lower runoff in other parts of the Morningstar catchment. As would be expected runoff values are lowest at the flatter downstream end of the catchment.

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Dec-98 Nov-00 Jan-09

Catchment Peak Volume of Runoff Peak Volume of Runoff Peak Volume of Runoff Station area (km2) flow flow (m3) (mm) flow flow (m3) (mm) flow flow (m3) (mm) No. 24001 770.2 161.1 19,233,552 25 147.4 27,329,098 35 123.7 26,733,810 35 24003 129.2 60.5 6,955,086 54 59.7 9,577,524 74 51.2 8,911,677 69 24004 242.1 100.1 10,754,941 44 82.9 12,615,482 52 58.1 9,902,498 41 24005 131.9 30.1 5,204,473 39 29.2 5,009,748 38 24008 806.0 166.7 19,078,823 24 158.0 28,088,204 35 134.8 28,840,791 36 24082 762.8 185.1 29,949,604 39 146.5 28,922,422 38 Table 7-J Peak flow, volume of flow and runoff for 3 events in the Maigue catchment.

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7.8 Deel catchment

The following events were selected to represent severe flood events within the Deel catchment:

Events selected were: . 11 – 12 and 21 – 22 October 1988; . 29 - 30 December 1998; . 31 July – 1 August 2008.

Throughout this study, emphasis has been placed on the selection of events which have occurred in the past 15 years primarily to increase the chance of data availability. However, hydrometric gauging station 24029 has significant periods of missing data in the past decade, therefore one event has been selected from 1988 to ensure the broadest picture of catchment response can be obtained.

The following gauging stations located across the catchment were selected to represent the catchment response:

• 24011 Deel at Deel Bridge; • 24012 Deel at Grange Bridge; • 24013 Deel at Rathkeale; • 24029 Deel at Inchirourke More; • 24030 Deel at Danganbeg.

7.8.1 Events of 11 – 12 and 21 – 22 October 1988

Instantaneous flow data was available at four gauging stations between 10th October 1988 (00:00 hours or first record of the day for digitised chart records) and 25th October 1988 (23:45 hours or last record of the day for digitised chart records). No data was available at station 24011. The data is summarised in Table 7-J.

Duration Peak Station Time of Volume of (days, flow Start time End time 3 No. 3 peak flow flow (m ) hours, (m /s) minutes) 11/10/1988 11/08/1988 14/10/1988 24030 49.9 5,339,153 03:00:25 12:05 00:23 00:48 24011 11/10/1988 11/08/1988 14/10/1988 24012 139.2 12,256,223 03:00:00 11:15 00:30 00:30 12/10/88 11/10/1988 14/10/1988 24013 129.0 16,558,548 02:23:00 01:15 04:00 03:00 12/10/1988 11/10/1988 14/10/1988 24029 44.9 7,680,509 02:20:10 04:04 07:46 03:56 Table 7-K Summary of timings and flows for the flood event 11 – 12 October 1988

Hydrographs (Figure 18a) covering the period 10th October to 24th October 1988 demonstrate the occurrence of four events, two of which 11th-12th and 21th-22th October were of a similar magnitude. The annual maxima peak flow for all gauges rests with either event, but for ease of comparison, Table 7-J and subsequent analyses will focus on the flows between 11th – 14th October.

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A review of the timing of peak flows indicates that flow peaked first at station 24012, located mid-catchment, downstream of the River Arra confluence. The River Arra and its tributaries drain the steep area (Knockanimpaha) to the West of Newcastle West. The steep gradient combined with the short distance to travel makes this source area likely to be responsible for the initial peak response at 24012.

There is a significant lag, of approximately 14 hours, between the peak in flow at 24012 and 24013.

The volume of flow and hydrograph peak at 24029 looks undersized considering that this station should capture all the flows. This could indicate by-passing of flows or be the result of the approach taken to calculate the volume which is an adequate approach for data with a 15 minute time step but may underestimate flows over larger time steps (for example digitised chart data).

Based on the annual maximum flow series fitted with a Gumbel distribution as detailed in Section 7.5 annual exceedance probabilities were estimated for the event at three locations, unfortunately an annual maxima series was not available for flows at 24029 (Ref. Table 7-K). The AEP estimates for gauges mid-catchment on the River Deel (24012 and 24013) denote a similar probability of occurrence. The higher probability of occurrence of 59% derived for station 24030 located within the upper reaches of the River Maigue supports the theory that runoff primarily originated from the River Arra and to the west of the catchment.

Peak flows at 24030 and 24029 seem to flatten out at flows of ~50 m3/s and ~45 m3/s respectively. This may be indicative of problems with the out-of-bank rating.

Oct-88

Estimated Annual Station Peak flow Station Name Watercourse 3 Exceedance No. (m /s) Probability (%)

24030 Danganbeg Deel 49.9 59 24011 Deel Br. Deel 24012 Grange Br. Deel 139.2 8 24013 Rathkeale Deel 129 12 Inchirouke 24029 More Deel 44.9 Table 7-L Estimated Annual Exceedance Probabilities for peak flows in the Deel catchment during October 1988 event

7.8.2 Event of 29 - 30 December 1998

Instantaneous flow data was available at four gauging stations between 29th December 1998 (00:00 hours) and 31st December 1998 (23:45 hours) (Ref. Table 7-L). Flow data was not available for 24029 Deel at Inchirourke More.

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Duration Peak Station Time of Volume of (days, flow Start time End time 3 No. 3 peak flow flow (m ) hours, (m /s) minutes) 30/12/1998 29/12/1998 31/12/1998 24030 49.4 6,172,866 01:20:30 12:45 18:30 15:00 29/12/1998 29/12/1998 31/12/1998 24011 89.1 7,969,141 01:17:00 23:00 07:15 00:15 29/12/1998 29/12/1998 31/12/1998 24012 125.8 12,166,949 01:18:15 23:30 06:15 00:30 30/12/1998 29/12/1998 31/12/1998 24013 137.8 16,677,755 01:17:30 19:00 15:00 08:30 24029

Table 7-M Summary of timings and flows for the flood event 29 – 30 December 1998

All four hydrographs (Figure 18b) point towards a double-peaked event, with the initial peak being the largest. Analysis has therefore focused on the first portion of the hydrograph ending at the inflection point for the second peak. However, this double peak does complicate the analysis and in particular the volume of flow due to the superposition of the two events on peak flows at 24013.

The lag in hydrographs between the locations is more evident on this shorter- duration plot. As observed in October 1988, flows at station 24012 peak early on but with the flow data from 24011 it is possible to observe a similar response just upstream. The response recorded in the upstream reaches at 24030 is much delayed by over 12 hours and may be more indicative of the location of rainfall within the catchment than of any general catchment response.

Annual exceedance probabilities presented in Table 7-M indicate that peak flows at 24011 and upstream at 24030 were a typical annual occurrence. However, peak flows downstream at 24012 and especially 24013 appear to be less frequent. From this we can deduce that peak flows at 24012 and 24013 were primarily the result of runoff from the catchment contributing to flows downstream of 24011. This includes the tributaries that drain the mountains bordering the west of the catchment, including the River Arra, River Daar and River Doally.

The flow record for 24030 again flattens out at peak flow ~50 m3/s indicative of a problem with the rating as bank full flow transitions to out-of-bank flow.

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Dec-98

Estimated Annual Station Peak flow Station Name Watercourse 3 Exceedance No. (m /s) Probability (%)

24030 Danganbeg Deel 49.4 62 24011 Deel Br. Deel 89.1 50 24012 Grange Br. Deel 125.8 19 24013 Rathkeale Deel 137.8 9 Inchirouke 24029 Deel More Table 7-N Estimated annual exceedance probabilities for peak flows in the Deel catchment during the December 1998 event

7.8.3 Event of 31 July – 1 August 2008

Instantaneous flow data was available at three gauging stations between 31st July 2008 (00:00 hours) and 4th August 2008 (23:45 hours) (Ref. Table 7-N). Flow data was not available at stations 24029 and 24030.

Duration Peak Station Time of Volume of (days, flow Start time End time 3 No. 3 peak flow flow (m ) hours, (m /s) minutes) 24030 01/08/2008 31/07/2008 02/08/2008 24011 118.7 9,781,073 02:02:30 04:30 20:15 22:45 01/08/2008 31/07/2008 03/08/2008 24012 153.6 14,495,010 02:07:30 05:00 19:45 03:15 01/08/2008 31/07/2008 04/08/2008 24013 131.0 19,132,945 03:11:30 23:00 22:30 10:00 24029 Table 7-O Summary of timings and flows for the flood event 31 July – 1 August 2008

Without flow data from the upper (24030) or lower (24029) reaches of the catchment, it is difficult to gain a broader picture of catchment response.

Hydrographs of this event (Figure 18 c) suggest a shorter lag between the rising limb of the hydrograph between 24012 and 24013 than that noted in the December 1998 event. This can be attributed to the high intensity short duration rainfall identified in Section 6.6.4.

A peak flow of 154 m3/s was recorded for the event mid-catchment at station 24012, considerably greater than the peak flow recorded at 24011. By the time flows peaked downstream at 24013, the peak had apparently been reduced to 131 m3/s due to attenuation storage. From this we can infer either that the most significant source of runoff contributing flows to the River Maigue was from the portion of the catchment draining into the River Maigue between gauges 24011 and 24012 or that gauge 24013 is underestimating peak flows or that gauge 24012 may be overestimating peak flows.

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The annual exceedance probability estimated for the peak flow at 24012 was 3% indicating that this was an infrequent event (Table 7-O). AEP estimates for peak flows recorded at the gauging stations upstream (24011) and downstream (24013) were higher at 13% and 11% and support the observation that this was a relatively isolated event on a catchment-scale.

Aug-08 Estimated Annual Exceedance Station Peak flow Probability No. Station Name Watercourse (m3/s) (%) 24030 Danganbeg Deel 24011 Deel Br. Deel 118.7 13 24012 Grange Br. Deel 153.6 3 24013 Rathkeale Deel 131 11 Inchirouke 24029 More Deel Table 7-P Estimated annual exceedance probabilities for peak flows in the Deel catchment during the August 2008 event

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160 160 24012 Grange Bridge 24011 Deel Bridge 24013 Rathkeale 24012 Grange Bridge 140 140 24029 Inchirourke More 24013 Rathkeale 24030 Danganbeg 24030 Danganbeg

120 120

100 100

80 80

Flow (cumecs) Flow 60 (cumecs) Flow 60

40 40

20 20

0 08/10/1988 10/10/1988 12/10/1988 14/10/1988 16/10/1988 18/10/1988 20/10/1988 22/10/1988 24/10/1988 26/10/1988 28/10/1988 0 28/12/1998 29/12/1998 29/12/1998 30/12/1998 30/12/1998 31/12/1998 31/12/1998 01/01/1999 01/01/1999 02/01/1999 02/01/1999

a) Events of October 1988 b) Event of 29 – 30 December 1998

180 24011 Deel Bridge 24012 Grange Bridge 160 24013 Rathkeale Figure 18 Hydrographs for gauging station in the Deel 140 catchment for a) October 1988 120 b) 29–30 December 1998 and c) 31 July to 1 August 2008 100

80 Flow (cumecs) Flow

60

40

20

0 30/07/2008 31/07/2008 01/08/2008 02/08/2008 03/08/2008 04/08/2008 05/08/2008 06/08/2008

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c) Event of 31 July – 1 August 2008

7.8.4 Deel catchment discussion

The hydrographs for all three events reflect a steep rising limb at all locations but, as to be expected, the recession is more prolonged in the lower reaches of the Deel catchment at gauging station 24029.

All three events highlight the significance of runoff contributions on peak flow from the area draining steep topography at the western boundary of the Deel catchment. This area drains into tributaries of the River Arra and eventually the River Deel between gauges 24011 and 24012. Rapid runoff from this area is thought to be the origin of the highest peak flow recorded from the three events, a flow of 153.6 m3/s recorded during August 2008 on the River Deel at Grange Bridge (24012). Following the 2008 event, flow gauges have been installed on the River Arra and further analysis of flows at this location is recommended.

The events analysed indicate an apparent attenuation in the peak flows down the catchment between 24012, 24013 and 24029. This could be attributed to an underestimation of flows at 24013, an overestimation of flows at 24012 or some form of storage effect between the two gauges.

Further analysis of the catchment response in terms of the peak flow, volume of flow and runoff (Table 7-P) reveals that runoff for all three events is greatest at 24013 within the lower reaches of the Deel catchment. Based on the runoff value from one event, it appears that runoff is lowest at 24029, at the base of the catchment and just upstream of where the River Deel becomes tidal.

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Oct-88 Dec-98 Aug-08

Catchment area Peak Volume of Runoff Peak Volume of Runoff Peak Volume of Runoff Station (km2) flow flow (m3) (mm) flow flow (m3) (mm) flow flow (m3) (mm) No. 24030 258.9 49.9 5,339,153 21 49.4 6,172,866 24 24011 281.2 89.1 7,969,141 28 118.7 9,781,073 35 24012 366.3 139.2 12,256,223 33 125.8 12,166,949 33 254.0 14,495,010 40 24013 438.8 130.4 16,558,548 38 137.8 16,677,755 38 131.0 19,132,945 44

24029 486.1 44.9 7,680,509 16

Table 7-Q Peak flow, volume of flow and runoff for 3 events in the Deel catchment

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7.9 Other catchments

This sub-catchment is a collection of smaller catchments located along the north of the unit of management and that discharge directly into the Shannon Estuary. No instantaneous flow data was available for any gauging stations located within this sub-catchment.

7.10 Conclusions

A review of daily mean flow data highlighted the possibility of long-terms trends in several flow and/or level series. Trends such as this in the flow series can reduce certainty in the index flood, QMED. Of those stations highlighted with a trend in the flow series the majority of stations will be revisited during the next phase through a high flows rating review, enabling further investigation and improvement in the confidence of QMED. Only gauging station 24082 will not be revisited.

To assist in the analysis of fluvial data, gauging stations were grouped according to their sub-catchment location; in either the River Maigue or River Deel. Three events were selected for each sub-catchment with instantaneous data.

Hydrographs produced for the Maigue catchment indicate a steep rising limb and an initial steep recession which appears to flatten out, indicative of a fast responding catchment. Another feature worth noting is the relationship between the peak flows at 24082, 24001 and 24008. The hydrographs indicate a consistent reduction in the peak flow and volume of flow between gauges 24082 and 24001, the consistency in the peak and volume of flood flows, casts some doubt on the record at 24082 but may also be the result of storage or flows by-passing the channel at 24001 and 24008.

Runoff within the Maigue catchment is significantly greater at 24003 on the Loobagh tributary. This correlates with the steepest topography of the Maigue catchment, where the Loobagh drains the Ballyhoura Mountains.

Annual exceedance probabilities estimated for each event on the Maigue suggested a range of values across the catchment. The lowest AEP estimated was 3% at two separate locations for two events; the River Maigue at Bruree (24004) in December 1998 and Athlacca on the River Morningstar during November 2000. AEP estimates for the three events analysed on the River Maigue, varied between 3% and 53%.

Hydrographs plotted for flood events on in the River Deel catchment reflect a steep rising limb and a prolonged recession in the lower reaches of the Deel catchment at gauging station 24029. Flattening of the peak at 24030 indicates some issue with the rating as flows transition to out-of-bank.

Significant runoff contributions to peak flows appear to originate from the River Arra and its tributaries draining the catchment at the western boundary of the Deel catchment.

A range of annual exceedance probabilities were estimated for the events and gauges analysed within the River Deel catchment. The lowest AEP estimated was 3% on the River Deel at Grange Bridge during the August 2008 event. Estimates for that event ranged between 3% and 13%, confirming it was a fairly infrequent event. AEP estimates for the three events analysed on the River Deel, varied between 3% and 62%.

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8 Historical Flood Risk Review

8.1 Introduction

A substantial amount of historical flooding information has been gathered using “floodmaps” (www.floodmaps.ie), which is a web-based flood hazard mapping resource managed by the Office of Public Works (OPW). It contains historical flood events in various areas of the Republic of Ireland, with links to archived reports, photographs and newspaper articles collected from local authorities, other state bodies and members of the general public.

The historical data from this website is related to flooding caused by fluvial, tidal and coastal factor within the past 120 years. It does not deal with flood events arising as a result of other causes such as burst pipes, surcharged or blocked sewers etc.

Quality codes have been assigned to define the reliability of the sources of information. This, however, excludes the newspaper articles and information to which other quality assurance or coding processes apply e.g. the OPW hydrometric data. The reliability is classified and graded as follows:

Code Description 1 Contains, for a given flood event at a given location, reliably sourced definitive information on peak flood levels and/or maximum flood extents. 2 Contains, for a given flood event at a given location, reliably sourced definitive information on flood levels and/or flood extents. It does not however fully describe the extent of the event at the location. 3 Contains, for a given location, information that, beyond reasonable doubt, a flood has occurred in the vicinity. 4 Contains flood information that, insofar as it has been possible to establish, is probably true.

Table 8-A Quality codes assigned to data in floodmaps (OPW)

The quality codes have been considered when summarising the historical flooding information with the priority given to data with quality code 1. The data with quality code 1 where available provides reliable information on peak flood levels and/or maximum flood extents and used in the analysis of the historical flood events. The detailed summary of all the historical flooding information for all the Communities at Risk (CAR) and Individual Risk Receptors (IRRs), together with the quality code, is shown in Appendix I. This is précised in the text and tables presented below.

Wherever the information is available in “floodmaps.ie” the number and type of properties and infrastructure affected in a CAR by a historical flood event is stated in the sections below. However, due to the qualitative nature of most of the information available in “floodmaps” it has often been found impossible to quantify these factors from the historical records.

The OPW recognises that the website is not a comprehensive catalogue of all past flood events and may not cover all flood events. The information included depends

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on the available records of the source organisation and is uploaded at their discretion. Therefore, the absence of any records of past flood events in any given location does not allow us to conclude that flooding has never occurred in that area.

8.2 Records of historical flood risk

The list of the Communities at Risk (CARs) and Individual Risk Receptors (IRRs) in this unit of management is shown in Tables 2-A and 2-B. Twelve CARs and one IRR have been identified in this area. Six of the CARs are in the Maigue catchment, 4 in the Deel catchment and the remaining two are found to the west of these two main catchments.

Where possible a representative gauging station for each of the CARs has been identified and flow or water level data of the gauging station has been used to estimate the Annual Exceedance Probability (AEP) of historical flood events obtained from the “floodmaps.ie” website. In the absence of any flow or water level estimates from a representative gauging station the AEP is estimated based on the order of magnitude of similar events within the same catchment. This estimate can therefore be considered as indicative only and should be treated with caution.

The AEPs for particular events are derived using the flood frequency plots indicated on the gauging station information sheets (Refer to Appendix H).

8.3 Maigue catchment

The historical floods known to have occurred in the CARs within the Maigue catchment and the corresponding flows estimated at a representative gauging station are summarised below.

8.3.1 Records of historical flood risk

The AEP of a given historical event as shown in Table 8-B was estimated based on annual maximum series flow data. However, in certain cases the date of the flood event and the annual maximum event might not match. Thus, where the dates are similar, the assumption has been made that the flow during the flood event was equivalent to the annual maximum flow of the hydrometric year in which the event occurred.

The AEP of flood events that occurred in Adare have been calculated based on the gauged water level record at Adare Manor gauging station (24009). The gauging station at Croom (24001) was used to calculate the AEP of floods that occurred at Croom.

Event Peak Flow Peak Level Estimated Flood Extents & Ranking (m3/s) (mOD -Malin) Annual Damages Exceedance Probability (AEP) (%) CAR 03 Adare 01/02 - 6.57 80 Land & road near Adare 4 Feb 2002 (Adare Manor) Station flooded. 07 Jan - 7.14 12 Station Road area 2 1999 (Adare Manor) affected by flooding. 26 Feb - 6.89 43 N21 road flooded. 4 1996 (Adare Quay)

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Event Peak Flow Peak Level Estimated Flood Extents & Ranking (m3/s) (mOD -Malin) Annual Damages Exceedance Probability (AEP) (%) Jan 1995 6.81 32 Land & road flooded. 3 (Adare Quay) 01 Dec - 7.40 4 No flooding details 1 1973 (Adare Manor) available. 11 Aug - - Agricultural land & roads 1946 flooded. CAR 20 Charleville 11 Aug - - - Houses & agricultural 1946 land flooded. CAR 22 Clarina Sep 1992 - ? Fields flooded. The flood depth estimated to be 0.30m (1ft) CAR 24 Croom 05/06 190.86 19.83 6 Croom-Bruff Road Aug 1986 (Croom) (Croom) (C1/31/4/2) & north of the road (C1/31/4) flooded. Dec 1983 192.46 19.85 6 No flooding details (Croom) (Croom) available. Dec 1973 133.12 20.31 41 No flooding details (Croom) (Croom) available. CAR 32 Kildimo New - - - - No flooding details - available. CAR 34 Kilmallock Aug 1946 - - - Roads & one house flooded. N.B: unless stated otherwise all levels are mAOD Malin Table 8-B Summary of historical flood events in CARs within the Maigue catchment

8.3.2 Discussion

The major cause of flood in the CARs of the Maigue catchment appeared to be fluvial and high tide. The historical flooding event record in this catchment goes back to 1946. The latest recorded flood was February 2002 which mainly affected areas around Adare.

Recurrence

A local news paper edited on 9 January 1999 indicated a recurrent flooding problem in Croom, during the 1990s. There is no information on whether any improvements have been made to alleviate flooding problems in the area.

February 2002

The February 2002 event was a combined fluvial and tidal event which affected Adare only.

January 1999

The Station Road area of Adare was reported to have been flooded on 7 January 1999. Minutes of a meeting that took place on 3 June 2005 indicated that this area is

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prone to flooding caused by surface runoff and tide. Low lying areas around Station Road are protected by embankments. The meeting minutes also noted that a new sewer would be laid in 2006 or 2007 to alleviate the problem. However, there is no information to confirm that this sewer has been laid.

February 1996

On 26 February 2011 the N21 road around Adare was flooded.

January 1995

Adare and Croom were flooded during the January 1995 event. It was reported that high tide combined with low barometric pressure caused this flood.

September 1992

On 15 September 1992 an area called Corcamore to the south west of Clarina, close to the mouth of the river Maigue, was flooded.

August 1986

Flooding affecting various part of the Limerick County occurred on 5 and 6 August 1986. One of those areas was Croom. This flooding event coincided with the storm- hurricane Charley, a major meteorological event that occurred in Ireland in August 1986.

December 1973

The data obtained from the “floodmaps” website indicated that Adare and Croom areas were flooded on 1 December 1973. A major rainfall that lasted for 5 days from 27 November to 1 December 1973 caused major flood events in the south and south west of Ireland. This flood event was identified as a Major Weather Event by Met Éireann on their website www.met.ie.

According to a record at Croom gauging station (24001) the flow on 1 December 1973 was 133m3/s with a peak flood level of 20.31mOD. The flood event corresponds with the annual maximum flow for that year. Its AEP was estimated to be 41% (approximately a 1 in 2 year event). However, the AEP estimated based on the water level at gauging station at Adare Manor (24009) was 4% (Equivalent to a 1 in 20 year event).

August 1946

On 11 August 1946 major floods occurred in Adare, Charleville, Croom and Kilmallock.

8.4 Deel catchment

The historical flood events known to have occurred in the CARs within the Deel catchment and the corresponding flows as estimated at a representative gauging station are summarised below.

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8.4.1 Records of historical flood risk

The nearest gauging station to Askeaton is Inchirouke More (24029), but that does not have an associated annual maximum series. The gauging station 24015 at Dromcolliher also does not have an associated annual maximum series. Station Danganbeg (24030) is located about 10km downstream of Dromcolliher and about 4.5km upstream of Newcastle West on the River Deel. The main cause of flooding in Dromcolliher village is the limited capacity of the two streams flowing through the village. Therefore the flood event at Dromcolliher cannot be analysed based on flow data from a gauging station on the River Deel.

Similarly there is no gauging station on the River Arra, a tributary of the river Deel. The river Arra passes through Newcastle West and is a source of flooding there.

Absence of a representative gauging station for each CAR means the AEP of historical flood events that occurred in each of the four CARs in the Deel catchment has not been estimated. The table below summarises the historical flood events that are known to have occurred in the Deel catchment.

Event Peak Flow Peak Level Estimated Flood Extents & Ranking (m3/s) (mAOD- Malin) Annual Damages Exceedance Probability (AEP) (%) CAR 04 Askeaton Recurring - - 50% Deel over-flowed and - flooded factory car park and L1236 Road. No premises affected. Frequency of the event indicated to be 1:2yr CAR 25 Dromcolliher 26 Aug Houses & roads flooded. 1997 12 Jul Houses & roads affected. 1997 30 Jun Houses & church 1995 flooded. 22 Feb Roads flooded. 1995 25 Jan Roads flooded. 1995 17 Jan Roads flooded. 1995 30 Dec Roads flooded. 1994 27 Dec Roads flooded. 1994 14 Jan Roads flooded. 1994 15 Jan Roads flooded. 1994 08 Dec Roads flooded. 1993 09 Sep Roads flooded. 1993 17 Jan Roads flooded. 1993

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Event Peak Flow Peak Level Estimated Flood Extents & Ranking (m3/s) (mAOD- Malin) Annual Damages Exceedance Probability (AEP) (%) 12 Nov Roads flooded. 1991 06 Feb Roads flooded. 1990 28 Dec Roads flooded. 1990 11 Jan Roads flooded. 1989 21 Oct Roads flooded. 1988 01 Feb Houses at Pike St & 1988 roads flooded. 22 Jan Roads flooded. 1988 25 Aug Roads flooded. 1986 06 Aug Houses, church & roads 1986 flooded. 28 Jul Roads flooded. 1986 22 Jan Roads flooded. 1986 16 Jan House at Pike St flooded 1984 CAR 44 Newcastle West Aug 2008 143 residential, 87 commercial properties & roads flooded. CAR 50 Rathkeale Jan 1969 - - - No flooding details - available. 23-24 - - - No flooding details - Dec 1968 available. 11-13 - - - No flooding details - Dec 1968 available. N.B: unless stated otherwise all levels are in mAOD-Malin

Table 8-C Summary of historical flood events in CARs within the Deel catchment.

8.4.2 Discussion

Major events are known to have occurred in the Deel catchment that affected Askeaton, Dromcolliher, Newcastle West or Rathkeale in the winter of 1968, August 1997 and August 2008. The 1968 winter flood affected Rathkeale area. In August 1997 Dromcolliher was flooded. Heavy rainfall and flood affected many parts of Ireland in the summer of 2008. One of the areas that is known to have been affected by this weather condition in the Deel catchment was Newcastle West.

Below is a brief summary of major historical flood events that are known to have occurred in the Deel Catchment.

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August 2008

On 1 August 2008 persistent rainfall in the previous days saturated the Arra catchment and caused a major flood in Newcastle West. The village is situated on the downstream reach of the River Arra. There is no gauging station on the River Arra. Therefore the flood flow during this flood event is not known. However, the annual exceedance probability (AEP) of the rainfall is estimated to be 0.15% (1 to 650 year) according to the “Newcastle West Flood Severity and Impact Report 1 August 2008” report prepared by JBA following this event.

In general the 2008 summer has been identified as a major meteorological event due to heavy rain and subsequent flooding in Ireland. However, there is no report that indicates that there was flooding in other CARs in the Deel catchment.

August 1997

On 26 and 27 August 1997 heavy rainfall caused flooding in different parts of Dromcolliher village. The village is located at the bottom of a mountain with two streams (Ahavarraga and the stream from Carroward) with steep catchments draining through the village. These streams are known to have caused flooding in different parts of the village. The AEP of the 1997 flood event was estimated to be 2% (1 in 50 years) , which is reported to exceed the capacity of the existing flood protection works.

An interim report compiled by Gibson O’Connor in September 1997 describes the impact of the 1997 flood on the village. The report also highlighted historical flood events prior to 1997. The major cause of flooding in the village appears to be inadequate hydraulic capacity of the streams which in most cases is exacerbated by the backwater effect of the downstream river. This is confirmed by the feasibility report prepared by ESB International carried out on behalf of Limerick County Council. The report also lists the historical flood events that occurred in Dromcolliher prior to 1997. These events are replicated in Table 8-C above.

The feasibility report investigated options for alleviating the flooding problem by enhancing the flood protection system in the village to cope with AEP of 1% (1 in 100 years) flow. However, no information has been found confirming that the preferred option has been implemented.

Winter 1968

The winter 1968 event resulted from prolonged heavy rain. There was heavy rain from 11 to 13 December (56mm), 23rd to 24th December (62mm) and 9th to 12th January (43mm) causing flooding in the Deel valley upstream of Rathkeale, at Deel Bridge and on the latter two occasions, at Balliniska – Bunoke. The duration of flooding on all occasions was about 24 hours.

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8.5 Other catchments

The two CARs identified in UoM 24 outside the Maigue or Deel catchments, Ballylongford and Foynes are both found to the west side of the two main catchments. The historical flood records that are known to have occurred in these two CARs are summarised in the following table.

8.5.1 Records of historical flood risk

Event Peak Flow Peak Level Estimated Flood Extents & Source (m3/s) (mAOD - Annual Damages Malin) Exceedance Probability (AEP) (%) CAR 09 Ballylongford 01 Feb - - - Kerry STW, street & Tidal 2002 some 10 houses flooded. 21 Aug - - - Carrig Island LIS01/769 Tidal 2001 flooded. 07 Dec - - - Land Commission Tidal 2001 Embankment LIS01/1584 flooded. 08 Mar - - - Land Commission Tidal 2002 Embankment LIS02/1993 flooded. 08 Apr - - - Land Commission Tidal 2008 Embankment LIS02/2104 flooded. 15 Jan - - - Gortnacooka Bridge area Tidal 2004 flooded. 06 Jan - - - At least 12 houses at Tidal & 2002 Bridge St, R551, R522, Rainfall LA water treatment plant Runoff flooded. 22 Oct - - - Streets at Ballylongford Tidal 1961 flooded. 28 Oct - - - A number of houses & Tidal 1927 streets flooded. CAR 29 Foynes 01 Feb - 6.28 - Domestic & commercial - 2002 properties, main street & N69 flooded. 23 Jan - - N69 & a number of - 2002 premises flooded. 08 Jan - - At least 4 residential & 2 - 2005 commercial properties flooded. 23 Feb - - N69 flooded for days. - 1995 30 - - - Flooding in the Railway - January Road area. 1995 N.B: unless stated otherwise all levels are mAOD-Malin

Table 8-D Summary of historical flood events in Ballylongford and Foynes

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8.5.2 Discussion

February 2002

Both Ballylongford and Foynes are within the Shannon tidal regime. They were both affected by the February 2002 event, reportedly caused by high tides, low pressure and strong south westerly winds.

In Ballylongford the high tide/surge level during this event reached 6.3m O.D which was estimated to have an AEP of 2% (1 in 50 year event). Kerry County Council Sewage Treatment Works (STW) was submerged below the tide level causing a backflow in the sewage pipes which backed up the toilets of some houses. The main street drainage system around the STW was also backed up and caused flooding as it is connected to the sewerage system by two gullies.

In Foynes a combination of high spring tide and high runoff in the Shannon, resulting from heavy rainfall over a prolonged period, increased the high tide level significantly on 1 February 2002. The tide overflowed the quay wall in the harbour area, flowed across the railway line and into the rear of a number of properties along the Main Street causing severe flooding to properties. The high tide recorded on this date was 6.28m O.D.

Other minor flooding was documented in Ballylongford e.g. October 1927, October 1961, August 2001, January 2002, March 2002, April 2002, January 2004, December 2007.

Other flood events in Foynes occurred in January 1995, February 1995, January 2002 and January 2005. These floods were caused by the rainfall runoff combined with inadequate culvert capacity. There is a small stream which runs from Cogrig along the side of the N69 road near Durnish and travels along the front gardens of a number of houses before discharging into the harbour area. The stream is culverted through the main street in Foynes. This flooding caused partial or complete blockage of the N69 road and flooding of the front gardens of the houses along the main street.

8.6 IRR 1 Tarbert Power Station

There is no record of flooding at the Tarbert Power Station and its immediate surroundings. However, minutes of a meeting organised by OPW which aimed at collecting flood data on 1 December 2005 suggested that the N67 road, which connects Tarbert village to the car ferry, floods at least twice a year.

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9 Proposed Methodologies for Future Work

9.1 Introduction

Within the scope of works for the Inception report, the OPW requested that a detailed method statement be provided which sets out the datasets to be used and the approaches to be followed for the hydrometric gauging station rating reviews and in the derivation of design flows. These are provided below.

9.2 Hydrometric gauging station rating reviews

The OPW have identified 11 stations (ref. Table 3-G), located within the Shannon Estuary South, for which rating reviews are required. For each of these gauging stations an assessment of the quality and limitations of the flood flow data will be made and where necessary the rating adjusted to reduce the uncertainty associated with it. The ratings will be extrapolated to beyond the highest recorded levels and if possible to the highest design flow (0.1% AEP). The methods used are likely to vary between sites depending on the availability of gaugings, survey data and local controls. Section 9.2.2 describes the techniques to be used. For all gauging stations for which a rating review is required, a 1D hydraulic model will be developed. Where the floodplain is too complex to be characterised in 1D a 2D representation of the floodplain will be included in the model based on 5m SAR data of LiDAR data as available. The modelled reach will extend sufficiently downstream such that any backwater effects within the channel are accounted for, and upstream to take account of approach conditions that could influence the rating.

9.2.1 Data required

All information made available will be used to assess the quality and uncertainty associated with the high flow ratings. The analysis will build on the work undertaken by Hydro-Logic in 2007 using the information listed below:

• Check flow gaugings; • Rating equations (historical and current) and associated dates; • Cross sectional survey data; • Gauge datum history.

9.2.2 Methodology

For all rated gauging stations, the upper range of the stage-discharge rating will be reviewed. A range of techniques will be employed to understand the quality and limitations of the high flow rating as detailed below:

A. An assessment of the quality of the check gaugings, the range in levels over which they have been taken and the frequency of gaugings. This will determine the quality of the underlying data on which the rating is based. B. Consideration of the limitations imposed by the gauging site i.e the cross section profile, stability, the presence of bypassing, backwater effects etc. C. Goodness of fit of the rating (as measured by the standard error) D. Identification of the upper limit in which reasonable confidence can be placed. E. Identification of any recommendations made in previous review not yet completed.

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The findings will be tabulated for each site and an overall classification given on a simple scale according to the confidence that can be placed in the high flow rating.

Extension of ratings For the 11 sites identified in the Brief, hydraulic modelling will be undertaken to extrapolate the stage discharge relationship to approximately 3 times the Qmed. Preliminary investigations of design flows suggest that the extended rating will include and exceed the 0.1% AEP design peak flow. At each target gauging station, extended cross sectional data will be input to the hydraulic modelling software to develop a representative hydraulic model of the reach and floodplain. The hydraulic model will be calibrated against higher flow check gaugings and then used to develop one or more high flow rating equations.

9.3 Design events

This section describes the data required, the methodology and the outputs from the proposed work to define the hydrological design flows. The design flows will be used in the hydraulic models, developed later in the project, to estimate extreme flood water levels. The method by which the design flows are used in the hydraulic models is also detailed.

9.3.1 Data required

The following data will be required to complete the design flood estimates in accordance with the methodology set out below:

• Gauging station surveys for the rating reviews (from survey contractors); • Hydraulic models of the gauging stations for rating review (11 gauges in UoM24) (by Jacobs); • Rating equations and check gaugings for all gauges requiring rating review that are still outstanding (gauging stations 24015, 24029 and 24030) (from OPW); • High flow rating reviews (by Jacobs); • Agreement on the way forward with each of the catchment area boundary anomalies highlighted in this report (Jacobs/OPW); • Hydrological Estimation Point definitions (by Jacobs).

9.3.2 Methodology

The dearth of sub-daily rainfall records for the catchment severely limits the application and accuracy of traditional rainfall runoff techniques. Rainfall runoff modelling has therefore been discounted. The uncertainty arising in the calibration of such models and the subsequent need to adjust the model flood flow predictions, to align with the flood frequencies derived from local flow gauge records, renders it ineffective for the Shannon RBD.

The method to be employed will draw upon the techniques set out in the Flood Studies Update (FSU) reports making best use of the gauged data to improve upon the estimates of Qmed, growth curves and the hydrograph shape.

The method to be employed will still enable testing of the effects of the hydrograph shape and peak to hydrological parameters like landuse change (e.g. urbanisation) or rainfall patterns, if this is required in the future. This can be done by creating a rainfall runoff model for a specific or typical catchment using the approach laid out in Work Package 3.5 (IBIDEM). Such a rainfall runoff model can be fitted to the synthetic hydrograph shape produced by FSU. The sensitivity of the flood TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc FINAL 88 of 100

hydrograph shape to changes in catchment parameters or rainfall can then be tested by adjusting these within the method used to simulate the runoff.

The Hydrological Estimation Points (HEPs) will be determined in accordance with Jacobs Technical Note 10 and the lessons learnt from the trial areas (see Section 4).

The data from the gauging stations detailed in Table 9 of the Stage II Tender Brief will be subjected to high flow rating reviews and on the basis of the review deemed suitable or not for Qmed estimation, derivation of a flood frequency growth curve and dimensionless hydrograph. Cognisance will be given to the gauges used in the FSU to develop the Qmed equation (10 in UoM 24, 6 of which will also be subject to rating review in this project) together with others assessed as being of sufficient quality and others which become so if annual maximum flow series are reworked following the rating review (potentially 11 in UoM 24, 6 which were employed in Qmed estimation for the FSU).

The reaches of watercourse to be modelled in the two main catchments in UoM 24, the Deel and Maigue, are both well served by flow gauges which ultimately, following the rating review, will be able to supply useful data to estimate Qmed and the dimensionless hydrograph shapes. The annual maximum flow series for the gauges are detailed on the summary sheets in Appendix H. Also detailed on these summary sheets are the preliminary estimates of Qmed and the dimensionless hydrographs for the highest recorded flows, prior to the rating review.

Specific details of the methodology proposed for each of the main item of the design hydrology are presented below:

Qmed The objective is to define Qmed at HEPs, in a manner that is consistent with reliable gauged Qmed data. The method should ensure that the Qmed estimate increases with increasing catchment area unless there is good hydrological justification for this not being the case.

The use of pivotal gauges to refine catchment descriptor Qmed estimates at ungauged sites is, where appropriate, one of the best ways of improving design flow hydrology and is a critical part of the flood frequency estimation process.

The Qmed equation from FSU will be employed to estimate Qmed at each HEP, referred to as the synthetic Qmed. At gauging stations where we have confidence in the Qmed estimate at the site based on the AMAX series, following the rating review, this will be compared to the synthetic FSU Qmed estimate and correction factors established for all such gauges. These correction factors will then be applied across the catchment, in the manner described in FSU Report Work Package 2.3 Flood Estimation in Ungauged Catchments but importantly employing hydrological knowledge to better judge how to make these adjustments.

Urban adjustments in Ireland will generally be very small in comparison with rural runoff from the catchments discharging to the modelled reaches. A standard approach to taking account of urbanisation is included within the equations for estimating Qmed. With regard to land-use change over long time horizons, for large rural catchments the impact of increased urbanisation will generally be extremely small, and will therefore generally be ignored in the derivation of flood discharges for future scenarios. Where catchment areas are small and urbanisation is likely to be

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significant, urban adjustment to take account of future land use changes will be considered, and applied as necessary.

Growth curves The objective is to define a growth curve for each HEP, that is representative of growth curves derived from reliably gauged data, such that the extreme flood discharges increase with increasing catchment area unless there is a good hydrological justification for it not so doing.

Growth curves for Ireland are generally flat and consistent between areas This reflects the wet nature of the catchments prior to large floods, which tend to be caused by the sequential passage of frontal rainfall systems over the catchments. The Flood Studies Report recommended a single growth curve for the whole of Ireland.

In UoM 24 the Gumbel (EV1) distribution fitted to the annual maximum series suggest growth factors to 1% AEP of 1.5 to 1.9 (Q100/Q2) for the Deel catchment and 1.6 to 2.3 for the Maigue catchment compared to that implied from the Flood Studies Report (FSR) of 2.06 (Q100/Q2). A growth factor of approximately 2 is very similar to that for the FSU rainfall estimates shown in Appendix D. Two main approaches are considered to estimate suitable growth curves:

• Gauged annual maximum series fitted to a distribution which can then provide a growth curve for use in the catchment. • A pooling group approach.

In a subsequent phase of this CFRAM study, Jacobs will decide on the most appropriate statistical distribution for design flood estimation for the unit of management (see Section 7.5). Based on FSU Work Package 2.2 the most likely candidates are the EV1 and lognormal distributions. We feel a consistent growth curve should be a priority for the area, as otherwise anomalies may arise in the magnitude of flood discharges for the more extreme floods moving down the catchment. Such growth curve data would be examined on a catchment and sub- catchment wide basis to determine whether patterns exist to better inform the selection of an appropriate growth curve.

The procedures set out in FSU Work Package 2.2 will be followed for the pooling group approach. Following liaison with OPW it was decided that these pooling groups should typically contain approximately 500 years of AMAX data, based on the following two considerations:

1. the focus of the design hydrology should normally be on the 100-year design event (as specified by OPW on the National Technical Coordination Group Meeting of 19 June 2012); and 2. FSU Work Package 2.2 recommends that the number of years should be 5 times the design event return period.

Both methods will be trialled for the gauges in the first sub-catchment area to be considered in UoM 24. Based on the trial a decision will then be made as to which option to apply on the project in the remaining sub-catchment areas.

Growth curves will be developed to allow the peak flows for design events to be estimated at each HEP for the 50%, 20%, 10%, 5%, 2%, 1%, 0.5% and 0.1% Annual Exceedance Probabilities (AEP).

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Hydrograph shape/volume The objective will be to use a hydrograph shape which is a reasonable representation of the gauged hydrograph shapes and volumes realised in the catchment. This will then be scaled to match the design flow for a given frequency, estimated as detailed above.

The options are to use a dimensionless hydrograph typical of the largest gauged floods, a non-parametric approach as described in FSU Work Package 3.1, Hydrograph Width Analysis, or to employ a synthetic hydrograph shape where regression-based expressions are used to estimate the values of relevant hydrograph descriptors, following a parametric approach, also described in FSU Work Package 3.1.

Jacobs is concerned that the approach outlined in FSU for defining a typical hydrograph shape has a bias to small and less relevant storm events, as about half of the calibration events are smaller than the 2-year design event. OPW has also indicated that they identified issues with using the parametric approach of Work Package 3.1 for ungauged catchments. Given the uncertainties involved in the changing hydrograph shape throughout the catchment, a more subjective method of defining hydrograph shape is considered more appropriate.

Where sufficient gauged data exists, e.g. on the rivers Deel and Maigue, a dimensionless hydrograph approach will be employed on the basis that it is better to use gauged data than synthetic data. A dimensionless hydrograph shape will be derived for each gauge using the more extreme gauged flood data. The typical hydrograph shape will broadly be the mean hydrograph shape from a number (usually three) of the largest floods recorded at the site (similar to those shown on the gauging station summary sheets in Appendix H). This method has the benefit that it focuses on the largest observed events at a gauging station only, and is therefore not biased towards smaller, less relevant events, which is the case for the method laid out in Work Package 3.1.

For smaller ungauged catchments the FSU synthetic hydrograph methodology will be considered but our preference will be to use a suitable transfer of hydrograph shape from gauged hydrographs from catchments with similar catchment descriptors (using FSU descriptors) where possible, as that way gauged data is used to its full potential.

9.3.3 Output

The outputs from the design flood hydrology will be peak flow estimates at each HEP for the 50%, 20%, 10%, 5%, 2%, 1%, 0.5% and 0.1% Annual Exceedance Probabilities (or other as agreed with OPW) together with a defined typical flood hydrograph shape for each HEP.

9.3.4 Application to hydraulic models

The objective will be to produce a hydraulic model that reproduces the flood hydrographs estimated at each HEP within a reasonable degree of accuracy.

FSU Work Package 3.4, Guidance for River Basin Modelling, describes a method of estimating tributary inflows so as to preserve the flood frequency in the main watercourse when applying FSU techniques to a hydraulic model. However, this method, whilst no doubt appropriate for smaller scale models of a limited extent, will

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unavoidably lead to errors which will accumulate as different tributary flows contribute throughout a larger system.

We therefore propose an alternative method to preserve the flood frequency along the main watercourse to match the design hydrographs estimated at each HEP. This alternative method is described below and illustrated in Figure 19.

The reaches to be hydraulically modelled will be considered between tributary junctions or, where the space between these results in a difference in catchment area of more than 10%, at intermediate hydrological model nodes. These locations will be coincident with HEPs. Flood hydrograph estimates for the main watercourse immediately upstream of the tributary (Hydrograph B in Figure 19) and upstream of the next tributary/model node (Hydrograph D in Figure 19) will be established as described above (for Qmed, growth curve and hydrograph shape). The difference between the two hydrograph estimates, derived by subtracting the upstream flow estimate from the downstream flow estimate for each hydrograph ordinate, will form the inflow from the tributary/location (i.e. Hydrograph D minus Hydrograph B gives Hydrograph E in Figure 19). The hydraulic model is run with the tributary inflow (Hydrograph E) and inflow at the upstream node (Hydrograph A). The resulting hydrograph from the model (Hydrograph D’) is then compared to the hydrograph originally estimated at the downstream nodel (Hydrograph D in Figure 19). The timing of the tributary inflow hydrograph (Hydrograph E in Figure 19) has to be adjusted by trial and error in running the hydraulic model to account for the travel time in the modelled reach. The target is that the peak flow differences are less than approximately 5% (Hydrograph D’ compared to Hydrograph D) and that the timing is representative. Additional nodes can be inserted and lateral inflows added (with flows derived using the same method as described here for tributary inflows) to reduce the error between nodes where appropriate. In this manner the design hydrograph peak and shape are preserved within a reasonable degree of accuracy throughout the model. The system is then repeated for any other tributaries requiring inflows to be modelled.

The approach has been successfully applied to the Lower River Thames for the Thames Region of the Environment Agency in the UK.

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Figure 19 Typical model hydrograph method

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9.4 Joint probability

Section 6.5.6 of the Brief requires a joint probability analysis. However, Section 7.5.2.1 requires mapping to indicate fluvially dominated extents and tidally dominated extents, and a merged map showing both.

Joint Probability is a complex issue that would benefit from the pooling of ideas and concepts from all members of the National Technical Coordination Group (NTCG). We therefore suggest that the most appropriate methodology is discussed and agreed through the NTCG forum. This will ensure that a consistent approach is adopted, making best use of data available along the Irish west coast. There remains a need to resolve the combinations of flows and sea levels to be run. However, the following broad principles will apply:

• Consideration of dependence based on review of the coincidence or otherwise of extreme tide and high fluvial events for which concurrent datasets are readily available. • A broad consideration of catchment size as this is likely to influence the degree of dependence. • The availability of coastal data on which to base an assessment of joint probability and the influence this may have on accuracy and method adopted (it is understood that less data may be available for the Irish west coast compared with other parts of the coastline).

9.5 Hydraulic model calibration

A proposed approach to hydraulic model calibration was set out in Section 7.4.2 of the Jacobs Stage 1 Tender Response. We propose to follow this methodology.

The limited amount of short duration rainfall data available in the region indicates that rainfall-runoff modelling will not provide the required confidence in the temporal distribution of rainfall and hence flows. There are no sub-daily rainfall gauges within Unit of Management 24. We shall therefore make best use of any reliable observed data to calibrate the hydraulic models, where this exists.

The hydraulic models will provide design flood flow and level frequency estimates that can be compared with gauged and observed data, and/or implied flood frequency, as a check on the modelled estimates. These comparisons are a vital reality check on the model, particularly where flood data is sparse.

9.6 Coastal flood modelling

9.6.1 Tide and surge

OPW have provided the results from the Irish Coastal Protection Strategy Study (ICPSS). This gives extreme tidal peak levels for the following annual probabilities: 50%, 20%, 10%, 5%, 2%, 1%, 0.5%, 0.1% for the south western coast and the Shannon Estuary.

Tidal curves will be generated using mean spring tidal cycles obtained at Carrigaholt, Foynes and Limerick from the Shannon Foynes Port Company and the Admiralty Report. To develop the extreme tide/surge hydrographs, a surge event of 30 hrs will be assumed. Then ICPSS extreme peak levels together with the assumed surge event profile and the mean spring tide levels will be used to create TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc FINAL 94 of 100

the tide/surge hydrographs associated with each annual probability event. This process is illustrated on Figure 20. The Mean High Water Springs (MHWS) tide levels will be chosen according to the geographic position of the sites under consideration relatively to the three tidal record locations mentioned above. 4 Mean Spring Tide 50% AEP Tide 3 Surge Event Profile

2

1

0 0 5 10 15 20 25 30 Water LevelWater (mOD) -1

-2

-3 Time (hrs)

Figure 20 Tide/Surge Hydrograph

For model sections where both tidal levels and fluvial flows affect the risk of flooding, a joint probability approach will be needed. This is discussed in Section 9.4.

9.6.2 Wave overtopping

Wave overtopping will be considered separately from tidal overtopping for tide/surge events where the tide+surge levels for the design events under consideration do not cause overtopping of the coastal defences, but the additional wave action would cause a flow across the defences that has the potential to cause flooding.

OPW has provided results from the ICWWS (Irish Coastal Wave & Water Level Modelling Study) screening analysis which highlight coastal locations potentially vulnerable to wave overtopping for the south western coast and the Shannon estuary.

For these locations, detailed wave and still water level model outputs are available in the form of shoreline prediction points and their associated predicted water level and wave climate (wave height Hmo, period Tp and mean direction) combinations for a range of annual probabilities (50%, 20%,10%, 5%, 2%, 1%, 0.5% and 0.1%). These outputs include both the current condition and two future scenarios (Mid Range Future Scenario [MRFS] and High End Future Scenario [HEFS]).

ICWWS data will be used in the coastal flooding models developed for this study to simulate flooding from wave overtopping of coastal defences for the design flood events.

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The following paragraphs detail the proposed methodology to simulate flooding from wave overtopping using the coastal flooding models developed for this study.

Site selection OPW has supplied eight locations which are potentially vulnerable to wave overtopping, and where modelling has been requested to simulate flooding arising from wave overtopping of coastal defences. These sites are:

• AFAs: Limerick, Shannon, Kilrush, Kilkee, Foynes and Tralee • IRRs: Shannon Airport and Tarbert Power Station

For those sites for which appropriate data ia provided, in agreement with OPW, we will undertake wave overtopping modelling. At each site, coastal defences are likely to vary in height, type and orientation relative to the mean direction of the incident waves. We will divide the coastal defences prone to wave overtopping in discrete reaches of similar characteristics and allocate a wave prediction point according to its geographic proximity and the mean direction of the incident waves.

Wave characteristics selection for the selected reaches of coastal defence For each flood event annual probability, ICWWS data consists of six combinations of extreme coastal water levels with predicted significant wave heights (Hmo), peak wave period (Tp) and mean wave direction. We will choose one combination for which the extreme water level is the closest to the average elevation of the stretch of defence identified whilst remaining below it. We will then calculate the mean overtopping discharge (in m3/s per m of coastal defence length) associated with the wave characteristics and the type of flood defence (sea dikes, embankments, vertical wall) involved. This calculation will be undertaken using the online tool available from the Overtopping Manual (EurOtop, 2007).

Generating a wave overtopping discharge hydrograph for the selected reaches of coastal defences As quoted from the overtopping manual, “in reality there is no constant discharge over the crest of a defence during overtopping. The process of wave overtopping is very random in time and volume”. A simplified approach is proposed here to generate a wave overtopping discharge hydrograph (flow vs. time) that will be input in the coastal flooding model at the landward side of the structure.

As illustrated in Figure 21 below, a wave overtopping discharge hydrograph will be generated assuming a 30-hour storm surge duration. Overtopping will occur when the selected wave height superimposed on the tide level exceeds the average elevation of the defence. During these overtopping periods, half of the mean overtopping discharge calculated above will be applied. This is because the wave height is at a maximum at the peak of the tide, but reduces to zero either side of the peak. On average, half the overtopping flow computed at peak tide can be assumed to flow over the defence, between the time of initial overtopping (some time prior to the peak tide) to the time overtopping ceases (some time after the peak tide). The time over which overtopping occurs is dependent on the tidal level and wave height selected.

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Tide + Stom surge Defence Level 6 "Waves"

5

4

3

2

1

Water Level (mOD) Level Water 0 0 5 10 15 20 25 30 -1

-2

-3 Time (hrs)

12 Wave overtopping discharge 10

8

6

4

2 Mean discharge in (l/s/m) in discharge Mean 0 0 5 10 15 20 25 30 -2 Time (hours)

Figure 21 (a and b) Wave overtopping hydrograph

It should be noted that if, for a given annual probability event, the tidal levels for all six wave - water level combinations (as described above) exceed the average elevation of the coastal defence reach, no simulation of flooding arising from wave overtopping will be carried out for this event. This is because the results will be represented by the separate tidal inundation modelling.

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10 Constraints, Data Problems and Other Issues

Several daily and instantaneous flow and level series for the key hydrometric stations identified in Section 3.2 have not been received (Table 10-A). Confirmation of whether the relevant data series exists is requested in the first instance.

There is no cost implication associated with the lack of provision of the data below, however, any lack of data may have an impact on the uncertainty and quality of the derived flood flow estimates, hydraulic model calibration and validation and rating reviews, all of which are programmed to be undertaken in the next phases of the project.

Daily mean Instantaneous Staff gauge Check Rating Station Data flows flow data readings gaugings equations number holder outstanding outstanding outstanding outstanding outstanding 24006 OPW Yes 24009 OPW Yes 24015 EPA Yes Yes Yes Yes 24029 EPA Yes Yes 24030 EPA Yes Yes 24031 EPA Yes 24033 EPA Yes 24036 EPA Yes 24067 OPW Yes 24081 OPW Yes 24084 OPW Yes Table 10-A Outstanding hydrometric data for Shannon Estuary South (UoM 24)

In the process of reviewing the available daily mean flow and level series, trends in the data series were identified at eight out of the twelve stations (see Section 7.3), these were stations 24001, 24003, 24005, 24008, 24011, 24012, 24013 and 24082. These trends may be indicative of external factors or reflect actual trends in the flow and/or level series. Any feedback from the data managers of the OPW would be useful to ensure maximum confidence in using the associated flows in future work.

The lack of sub daily rainfall data for the unit of management precludes the use of rainfall-runoff modelling. Alternative methods are proposed, as set out in Section 9 of this report. These may give rise to difficulties in future use to examine the potential impacts of land use change, although sensitivity analysis could be used to overcome these difficulties.

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11 Conclusions

In order to avoid abortive work the definition of Hydrological Estimation Points (HEPs) has been postponed until the Flood Risk Review has been completed and the final list of Areas of Potential Significant Risk agreed with OPW. However, the results of a trial application of the proposed method to define HEP are presented herein together with lessons learned.

Catchment areas, defined using a range of datasets, have been compared and the comparison reported where catchment areas to gauging stations and Communities at Risk exceed 10%. The discrepancies identified have been documented herein such that the way forward can be agreed with OPW before the design hydrology commences.

A review of rainfall and flow gauges in the catchment has been undertaken and specific flood events studied to better understand the data and provide a hydrological understanding of the data for use in subsequent phases of the project.

Nine Met Éireann daily storage raingauges have been identified within the Shannon Estuary South Unit of Management, however, data was only provided for eight. No sub-daily rainfall data was available and this has limited the rainfall durations analysed and the conclusions that were able to be drawn.

Historical rainfall depths for these events have been studied for a range of durations. The results suggest that events were the result of both winter depressions, characterised by a moderately intense rainfall event preceded by prolonged rainfall, and a summer convective event characterised by high intensity short duration rainfall.

Annual exceedance probabilities (AEPs), for these selected rainfall events, have been estimated from actual data. These indicate that the majority of rainfall events studied were typical annual events with an AEP of 50% or greater. However, the lowest annual exceedance probability estimated was 4% for a 1 day rainfall depth at station 4811 during the July 2008 event. These AEPs have been compared to theoretical AEPs derived from the Flood Studies Update (FSU). FSU AEPs were lower AEPs at station 4611 and higher AEPs at stations 4811 and 5111. These differences appear to suggest that the FSU Depth Duration Frequency (DDF) estimates do not accurately reflect the DDF relationship at the three rainfall stations considered. However, as rainfall runoff modelling is not proposed (see below), this finding will not affect the proposed future work for this Unit of Management.

A review of daily mean flow data highlighted the possibility of long-terms trends in several flow and / or level series. Trends such as this in the flow series can reduce certainty in the index flood, QMED. Of those stations highlighted with a trend in the flow series the majority of stations will be revisited during the next phase through a high flows rating review, enabling further investigation and improvement in the confidence of QMED. Only gauging station 24082 will not be revisited.

To assist in the analysis of fluvial data, gauging stations were grouped according to their sub-catchment location; in either the River Maigue or River Deel. Three events were selected for each sub-catchment and the instantaneous flow data studied for these events.

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Hydrographs produced for the Maigue catchment indicate a steep rising limb and an initial steep recession which appears to flatten out, indicative of a fast responding catchment. The hydrographs indicate a consistent reduction in the peak flow and volume of flow between hydrometric gauges 24082 and 24001, the consistency in the peak and volume of flood flows, casts some doubt on the record at hydrometric gauge 24082 but may also be the result of storage or flows by-passing the channel at 24001 and 24008.

Runoff within the Maigue catchment is significantly greater than the Deel catchment. This correlates with the steepest topography of the Maigue catchment, where the Loobagh drains the Ballyhoura Mountains.

Annual exceedance probabilities estimated for each event on the Maigue suggested a range of values across the catchment. For the three events analysed on the River Maigue, the AEP estimated at the hydrometric gauges varied between 3% and 53%.

Hydrographs plotted for flood events on in the River Deel catchment reflect a steep rising limb and a prolonged recession in the lower reaches of the Deel catchment. Flattening of the peak flows at hydrometric gauge 24030 indicates some issue with the rating as flows transition to out-of-bank.

Significant runoff contributions to peak flows appear to originate from the River Arra and its tributaries draining the catchment at the western boundary of the Deel catchment.

A range of annual exceedance probabilities were estimated for the events and gauges analysed within the River Deel catchment. Estimates for the three events analysed on the River Deel, varied between 3% and 62%.

Methodologies for the hydrometric gauging station rating reviews procedure to be applied to 11 gauges in the catchment and for the design flow estimation methods have been proposed together with the design event hydrological methodology to be adopted for the study. A traditional rainfall-runoff modelling approach is not considered practical due to the lack of short duration rainfall data within the catchment.

Consideration of the tidal issues has concluded that Joint Probability is a complex issue that would benefit from the pooling of ideas and concepts from all members of the NTC Group. We therefore suggest that the most appropriate methodology is discussed and agreed through the NTC Group forum. This will ensure a consistent approach is adopted.

Where possible each CAR has been associated with a flow gauging station, which will provide essential information to derive local flood estimates. However, CARs Ballylongford, Kildomo New, Clarina and Foynes did not have such local data. It is recommended that consideration is given to improving the flow gauging network in the vicinity of these CARs for the benefit of future flood studies.

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12 References

Compass Informatics (2009), Preparation of Digital Catchment Descriptors, Flood Studies Update, Work Package 5.3, January 2009

Dunsmore, S.J. (2007), River Thames Flood Hydrology Design Curves. Water and Environment Journal. Vol. 11 (1), pp 67-71

EPA (2011), Register of Hydrometric Stations in Ireland, Website: http://www.epa.ie/downloads/pubs/water/flows/name,12745,en.html (Accessed March 2011)

EPA Hydronet Website Website: http://hydronet.epa.ie/introduction.htm (Accessed March - June 2011)

EurOtop (2007), Wave Overtopping of Sea Defences and Related Structures: Assessment Manual, August 2007 Website: http://www.overtopping-manual.com/ (Accessed May 2012)

Hydro-Logic Ltd (2006), Review of flood flow ratings for Flood Studies Review, Work Package 2.1, Flood Studies Update

JBA Consulting (2009), IBIDEM (Interactive Bridge Invoking the Design Event Method), Flood Studies Update, Work Package 3.5, July 2009

JBA Consulting (2010), Guidance for River Basin Modelling (Revised Final Report), Flood Studies Update, Work Package 3.4, June 2010

Kiely, G., Leahy, P., Fenton, M., Donovan, J. (2008), Flood event analysis, Flood Studies Update, Work Package 3.2, University College Cork, Hydromet Research Group, Centre for Hydrology, Micrometeorology and Climate Change

Met Éireann (2007), Estimation of point rainfall frequencies, Flood Studies Update, Work Package 1.2

Murphy, C. (2009), Flood Estimation in Ungauged Catchments, Flood Studies Update, Work Package 2.3, Irish Climate Analysis and Research Units (ICARUS), Department of Geography

National University of Ireland (2009), Frequency analysis, Flood Studies Update, Work Package 2.2, Department of Engineering Hydrology and The Environmental Change Institute, Galway

Office of Public Works (2009), Base Flow Index derived from soils (Draft Final Report), Flood Studies Update, Work Package 5.2, August 2009

Office of Public Works Floodmaps Website Website: http://www.floodmaps.ie/ (Accessed March to July 2011)

Office of Public Works Hydro- Data Website Website: http://www.opw.ie/hydro/ (Accessed March to July 2011)

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O’Connor, K., Goswami, M. (2009), Hydrograph Width Analysis, Flood Studies Update, Work Package 3.1, National University of Ireland (2009), Department of Engineering Hydrology Environmental Change Institute

Reed, D.W. (2007), PROPWET for Ireland: a dimensionless index of typical catchment wetness, Flood Studies Update, Work Package 5.4, May 2007

University College Dublin (2006), Scoping Study of Urban Flooding Issues, Flood Studies Update, Work Package 4.1, Centre for Water Resources Research, October 2006

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Appendix A - All hydrometric stations listed in EPA register

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Station Station Record Station name Waterbody Station type Available data Operating Authority Easting Northing Type Record End number status start 24001 CROOM MAIGUE Active Data Logger Office of Public Works 151274 141001 River 01/10/1953 Autographic 24002 GRAY'S BR. CAMOGE Active Office of Public Works 157932 140276 River 01/10/1953 Recorder Autographic 24003 GARROOSE LOOBAGH Active Office of Public Works 155008 127458 River 01/10/1956 Recorder 24004 BRUREE MAIGUE Active Data Logger Office of Public Works 155078 130369 River 01/10/1953 Autographic 24005 ATHLACCA MORNINGSTAR Active Office of Public Works 155782 134290 River 01/10/1953 Recorder Autographic 24006 CREGGANE MAIGUE Active Office of Public Works 153408 127284 River 01/101956 Recorder 24007 CAHERASS MAIGUE Inactive Staff Gauge Only Flow Measurements Office of Public Works 150156 142678 River Autographic 24008 CASTLEROBERTS MAIGUE Active Water Level and Flow Office of Public Works 148000 143779 River 01/11/1973 Recorder Autographic 24009 ADARE MANOR MAIGUE Active Office of Public Works 147355 146220 Tidal 01/11/1973 Recorder 24011 DEEL BR. DEEL Active Data Logger Office of Public Works 129938 132738 River 01/09/1954 24012 GRANGE BR. DEEL Active Data Logger Office of Public Works 130810 135013 River 01/09/1954 24013 RATHKEALE DEEL Active Data Logger Office of Public Works 136009 141444 River 01/09/1953 Limerick County 24014 BROADFORD BUNOKE TRIB Inactive Staff Gauge Only Flow Measurements 133158 121701 River 10/05/1978 31/07/2003 Council Limerick County 24015 DROMCOLLIHER AHAVARRAGH Active Data Logger Flow Measurements 137926 121362 River 22/09/1977 28/01/1999 Council Autographic Limerick County 24016 KILMALLOCK LOOBAGH Inactive Water Level and Flow 160670 128462 River 24/07/1980 17/04/1984 Recorder Council Autographic Limerick County 24017 ROBERTSTOWN ROBERTSTOWN Inactive Water Level and Flow 126908 149709 River 02/10/1981 15/05/2000 Recorder Council Limerick County 24018 SHANAGOLDEN ROBERTSTOWN Inactive Staff Gauge Only Flow Measurements 125626 147179 River 20/03/1978 12/12/2007 Council Limerick County 24019 BARRIGONE AHACRONNANE Inactive Staff Gauge Only Flow Measurements 128407 149779 River 15/09/1977 12/09/1983 Council Limerick County 24020 DAAR BR DAAR Inactive Staff Gauge Only Flow Measurements 127561 135948 River 10/07/1975 16/02/2009 Council CULLENAGH Limerick County 24021 DEEL Inactive Staff Gauge Only Flow Measurements 127705 133527 River 09/02/1978 15/08/1984 HOUSE Council

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Station Station Record Station name Waterbody Station type Available data Operating Authority Easting Northing Type Record End number status start Limerick County 24022 HOSPITAL MAHORE Active Data Logger Water Level and Flow 170565 136283 River 12/06/1984 Council Limerick County 24023 KNOCKLONG DRUMCAMOGE Proposed Data Logger 171883 132196 River Council Limerick County 24024 GARRYSPILLANE MORNINGSTAR Inactive Staff Gauge Only Flow Measurements 174823 127860 River 01/05/1978 06/12/1993 Council Limerick County 24025 BRUFF MORNINGSTAR Inactive Staff Gauge Only Flow Measurements 163101 135832 River 30/05/1978 21/07/2009 Council Limerick County 24026 KILFINNANE LOOBAGH Active Staff Gauge Only Flow Measurements 168690 123293 River 04/05/1979 Council Limerick County 24027 DOORLUS MAIGUE TRIB Inactive Staff Gauge Only Flow Measurements 149779 135055 River 16/02/1978 23/05/1984 Council Limerick County 24028 BALLYNABANOGE MAIGUE TRIB Inactive Staff Gauge Only Flow Measurements 152463 136197 River 04/05/1978 27/09/1990 Council INCHIROURKE Limerick County 24029 DEEL Active Data Logger Water Level and Flow 134386 149141 River 12/10/1982 MORE Council Limerick County 24030 DANGANBEG DEEL Active Data Logger Water Level and Flow 131830 129038 River 05/05/1980 Council Limerick County 24031 NEWCASTLE WEST ARRA Inactive Staff Gauge Only Flow Measurements 128764 133488 River 12/12/1991 28/09/2004 Council WHITE Limerick County 24032 LOGHILL Inactive Staff Gauge Only Flow Measurements 119350 149326 River 19/09/1977 15/09/1988 [LIMERICK] Council WHITE Limerick County 24033 BALLYHAHILL Active Data Logger Water Level and Flow 119497 146092 River 28/07/1980 [LIMERICK] Council 24034 RIVERSFIELD WEIR LOOBAGH Active Data Logger Office of Public Works 163231 126306 River 31/10/1985 WHITE Limerick County 24035 GORTADROMA Active Staff Gauge Only Flow Measurements 121311 143196 River 19/02/1987 [LIMERICK] Council 24036 GOLDEN VALE BALLINCOLLY Inactive Staff Gauge Only Flow Measurements Golden Vale Foods 154210 125589 River BALLINCOLLY 24037 HELENA'S BRIDGE Inactive Staff Gauge Only Flow Measurements Golden Vale Foods 153835 125759 River TRIB Limerick County 24038 ARDAGH STREAM Inactive Staff Gauge Only Flow Measurements 128052 139570 River 25/07/1989 25/10/1995 Council Limerick County 24039 BALLYLANDERS MORNINGSTAR Inactive Staff Gauge Only Flow Measurements 175597 124313 River 07/09/1989 11/11/1992 Council Limerick County 24040 KILTEELY BALLYNAMONA Inactive Staff Gauge Only Flow Measurements 172640 142268 River 19/02/1990 12/11/1993 Council

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Station Station Record Station name Waterbody Station type Available data Operating Authority Easting Northing Type Record End number status start Limerick County 24041 CARRIGKERRY DAAR Inactive Staff Gauge Only Flow Measurements 122140 138705 River 12/09/1989 30/10/1997 Council KILMEEDY Limerick County 24042 KILMEEDY Inactive Staff Gauge Only Flow Measurements 138383 129610 River 19/02/1990 19/02/1990 STREAM Council 24043 COOLNAGOUR DEEL Inactive Staff Gauge Only Flow Measurements Cork County Council 141186 121415 River Limerick County 24044 RYLANES CLONSHIRE Proposed Data Logger 141797 136606 River Council Limerick County 24045 CANTOGHER BUNOKE Active Data Logger Water Level and Flow 128170 125280 River 09/07/2007 Council GORTNALUGGIN Limerick County 24046 FINGLOSHA Active Data Logger Water Level Only 139041 127219 River 05/08/2004 BR. Council 24047 ROSSBRIEN RLY BR BALLINACURRA Active Recorder Water Level and Flow Office of Public Works 157220 154018 River 16/12/1998 BALLINACURRA 24048 BALLINACURRA Active Recorder Water Level Only Office of Public Works 156279 154846 River 18/12/1998 D_S BALLINACURRA 24049 BALLINACURRA Active Recorder Water Level Only Office of Public Works 156305 154843 River 17/12/1998 U_S BALLINACURRA 24050 STREAM Inactive Recorder Water Level Only Office of Public Works 157300 154900 River 23/11/1998 09/06/2000 GARDENS 24051 HUNTSFIELD DOORADOYLE Inactive Recorder Water Level Only Office of Public Works 157300 154900 River 23/11/1998 09/06/2000 24060 TARBERT SHANNON ESTY Inactive Recorder Water Level Only ESB 108400 149400 Tidal MAIGUE 24061 FERRY BR. Active Recorder Water Level Only Office of Public Works 148256 152469 Tidal 01/01/1940 ESTUARY MAIGUE 24062 ADARE QUAY Active Recorder Water Level Only Office of Public Works 145935 146661 Tidal 01/08/1966 ESTUARY Autographic 24067 NORMOYLE'S BR. GREANAGH Active Office of Public Works 144057 145659 Tidal 01/11/1963 Recorder 24081 CURRACHASE CURRACHASE Inactive Staff Gauge Only Office of Public Works 141334 149352 Lake Autographic 24082 ISLANDMORE MAIGUE Active Office of Public Works 151496 139971 River 03/11/1975 Recorder Autographic 24083 TOOREEN CAMOGE Inactive Office of Public Works 152497 139531 Lake 01/10/1977 01/10/1987 Recorder KILMALLOCK 24084 MAIGUE Inactive UNKNOWN Office of Public Works 161298 127727 Lake CREAMERY 24093 ROSSBRIEN RLY BR BALLINACURRA Active Data Logger Office of Public Works 157220 154018 River 16/12/1998

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Station Station Record Station name Waterbody Station type Available data Operating Authority Easting Northing Type Record start number status End BALLINACURRA 24094 BALLINACURRA Active Data Logger Office of Public Works 156279 154846 River 18/12/1998 D_S 24100 GORTBOY HOTEL DEEL Active Recorder Water Level and Flow Office of Public Works 128600 133493 River 21/11/2008

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Appendix B - Double mass rainfall plots

8000

7000

6000

5000

4000

3000 Cumulative rainfall (mm) 6111

2000

1000

0 0 1000 2000 3000 4000 5000 6000 7000 8000 Cumulative rainfall (mm) 4611

30000

25000

20000

15000

10000 Cumulative rainfall (mm) 5111

5000

0 0 5000 10000 15000 20000 25000 30000 Cumulative rainfall (mm) 4911

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14000

12000

10000

8000

6000

4000 Cumulative Cumulative rainfall (mm) 6311

2000

0 0 2000 4000 6000 8000 10000 12000 Cumulative rainfall (mm) 5711

7000

6000

5000

4000

3000 Cumulative rainfall (mm) 5811 2000

1000

0 0 2000 4000 6000 8000 10000 12000 Cumulative rainfall (mm) 5111

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30000

25000

20000

15000

10000 Cumulative rainfall (mm) 5111

5000

0 0 5000 10000 15000 20000 25000 Cumulative rainfall (mm) 4811

25000

20000

15000

10000 Cumulative rainfall (mm) 5711 5711 (mm) rainfall Cumulative

5000

0 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Cumulative rainfall (mm) 4911

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Appendix C - 1-day and 4-day rainfall probability plots

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80 60

70 50 60 40 50

40 30

30 20 (mm) rainfall maxima annual day 1 20 (mm) rainfall maxima annual day 1 10 10 2 5 10 25 50 100 200 2 5 10 25 50 100 200 Return Period (yrs) Return Period (yrs) 0 0 -2-10123456 -2-10123456 Reduced Variate Reduced Variate

a) Raingauge 4611 – Tarbert Island b) Raingauge 4811 – Patrickswell

70

60

50

40

30

20 (mm) rainfall maxima annual day 1 10 2 5 10 25 50 100 200 Return Period (yrs) 0 -2-10123456 Reduced Variate

c) Raingauge 5111 – Rathkeale

Figure C-1 (a-c) 1-day rainfall probability plots

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140 140

120 120

100 100

80 80

60 60

40 40 4 day annual maxima rainfall (mm) rainfall maxima annual day 4 (mm) rainfall maxima annual day 4

20 20

2 5 10 25 50 100 200 2 5 10 25 50 100 200 Return Period (yrs) Return Period (yrs) 0 0 -2-10123456 -2-10123456 Reduced Variate Reduced Variate a) Raingauge 4611 – Tarbert Island b) Raingauge 4811 – Patrickswell

140

120

100

80

60

40

(mm) rainfall maxima annual day 4

20 2 5 10 25 50 100 200 Return Period (yrs) 0 -2-10123456 Reduced Variate

c) Raingauge 5111 – Rathkeale

Figure C-2 (a-c) 4-day rainfall probability plots

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Appendix D - FSU depth duration frequency plots

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Depth Duration Frequency Curves for raingauge 4811 (from FSU Workpackage 2.2)

250 4811 1 day 4811 2 day 4811 4 day 4811 10 day 200

150

100 Rainfall depth (mm) Rainfall

50

0 0 102030405060 Annual Exceedance Probability (%)

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Depth Duration Frequency Curves for raingauge 4911 (from FSU Workpackage 2.2)

250

4911 1 day 4911 2 day 4911 4 day 4911 10 day 200

150

100 Rainfall depth (mm) Rainfall

50

0 0 102030405060 Annual Exceedance Probability (%)

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Depth Duration Frequency Curves for raingauge 5111 (from FSU Workpackage 2.2)

250 5111 1 day 5111 2 day 5111 4 day 5111 10 day 200

150

100 Rainfall depth (mm) Rainfall

50

0 0 102030405060 Annual Exceedance Probability (%)

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Appendix E - Daily mean flow review

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Daily flow data only Daily level data only No. of No. of UoM 24 No. of No. of No. of beyond No. of No. of No. of Quality Total No. of beyond No. of No. of No. of Quality Total Station Sub- Record good fair poor limit unchecked cautionary missing code not number good limit unchecked cautionary missing code not number Comment on visual no. Station name Waterbody catchment Record start End days days days days days days days known of days days days days days days known of days inspection of record Clear rising trend in water 24001 CROOM Maigue Maigue 01/10/1953 5304 7076 904 0 0 27 526 21 13858 13305 0 27 0 526 0 13858 level record. Flows ok. No obvious inconsistencies 24002 GRAY'S BR. Camoge Maigue 01/10/1953 8345 0 359 0 333 7 9044 or trends. 31/5/81 - sudden drop in level. Trend of gradually rising water level from May 24003 GARROOSE Loobagh Maigue 01/10/1956 11568 0 0 0 0 26 2265 0 13859 11568 0 26 0 2265 0 13859 1981. Flows ok. 24004 BRUREE Maigue Maigue 01/10/1953 7858 2348 0 0 293 155 634 126 11414 10276 0 785 0 749 0 11810 Trend of gradually rising water level over period of 24005 ATHLACCA Morningstar Maigue 01/10/1953 7559 0 596 0 8606 0 16761 record Level data shows irregularities and missing values- poor record. No flow 24006 CREGGANE Maigue Maigue 01/10/1956 2878 0 27 0 10866 88 13859 data Anomalous dip in water levels Mar-Aug 86. Trend of gradually rising water level over period of record in both level and flow record. Most recent import has no flow flags assigned. Post CASTLE- 1979 WL data looks ok. Flow 24008 ROBERTS Maigue Maigue 01/11/1973 9060 2422 0 0 0 68 696 0 12939 11974 0 155 0 340 2 13436 looks ok Slight trend of gradually rising water level over period of record. No flags on 24011 DEEL BR. Deel Deel 01/09/1954 98 4259 825 0 2 61 232 0 5477 7684 0 1 0 69 169 7923 data. Declining flows between Sept-1964 and May 1965. Trend of flows gradually 24012 GRANGE BR. Deel Deel 01/09/1954 4677 8351 4724 0 89 437 899 0 19177 18542 0 87 1 544 0 19174 increasing since May 1965. Trend of gradually rising water levels from approx. Sept 1990, also evident in 24013 RATHKEALE Deel Deel 01/09/1953 0 11039 1664 0 0 24 1050 82 13859 13027 0 0 24 737 70 13858 flow series. RIVERSFIELD 24034 WEIR Loobagh Maigue 31/10/1985 1362 632 0 0 0 79 156 19 2248 2012 0 74 16 156 1 2259 Trend of increasing peak flows throughout period of record. Water levels suggest an gradual increase in low 24082 ISLANDMORE Maigue Maigue 03/11/1975 128 8226 0 0 0 8 151 0 8513 8356 0 6 0 151 0 8513 flows also.

NB: Grey squares indicate no data.

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Appendix F - Flood frequency probability plots

250

200

150

100 AMAX Flow (cumecs) Flow AMAX

50

2 5 10 25 50 100 200 Return Period (yrs) 0 -2-10123456 Reduced Variate

Hydrometric station 24001

51

50

49 AMAX FlowAMAX (cumecs)

48

2510 25 50 100 200

Return Period 47 -4-3-2-101234567 Reduced variate

Hydrometric station 24002

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

61.0

60.5

60.0

59.5 AMAX FlowAMAX (cumecs) 59.0

58.5 25102550 100 200

Return Period 58.0 -4-3-2-10123456 Reduced variate

Hydrometric station 24003

120

100

80

60 AMAX FlowAMAX (cumecs) 40

20

2510 25 50 100 200

Return Period 0 -2-10123456 Reduced variate

Hydrometric station 24004

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

35

30

25

20

15 AMAX FlowAMAX (cumecs)

10

5 2 5 10 25 50 100 200

Return Period

0 -3-2-10123456 Reduced variate

Hydrometric station 24005

8

7 AMAX FlowAMAX (cumecs) 6

2 5 10 25 50 100 200

Return Period 5 -3-2-10123456 Reduced variate

Hydrometric station 24006

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

250

200

150

100 AMAX FlowAMAX (cumecs)

50

2 5 10 25 50 100 200 Return Period 0 -2-10123456 Reduced variate

Hydrometric station 24008

8

7 AMAX FlowAMAX (cumecs) 6

2 510 25 50 100 200

Return Period 5 -3-2-10123456 Reduced variate

Hydrometric station 24009

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

200

180

160

140

120

100

80 AMAX FlowAMAX (cumecs)

60

40

2 5 10 25 50 100 200

20 Return Period

0 -3-2-10123456 Reduced variate

Hydrometric station 24011

180

160

140

120

100

80 AMAX FlowAMAX (cumecs) 60

40

20 Return Period

251025 50 100 200 0 -3-2-10123456 Reduced variate

Hydrometric station 24012

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

160

140

120

100

80

60 AMAX FlowAMAX (cumecs)

40

20 2510 25 50 100 200

Return Period 0 -3-2-10123456 Reduced variate

Hydrometric station 24013

25

20

15

10 AMAX FlowAMAX (cumecs)

5

2510 25 50 100 200

Return Period 0 -2-10123456 Reduced variate

Hydrometric station 24022

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

80

70

60

50

40

30 AMAX FlowAMAX (cumecs)

20

10 2510 25 50 100 200

Return Period 0 -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Hydrometric station 24030

40

35

30

25

20

15 AMAX FlowAMAX (cumecs)

10 Return Period

2 5 10 25 50 100 200 5

0 -3-2-10123456 Reduced variate

Hydrometric station 24034

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

250

200

150

100 AMAX FlowAMAX (cumecs)

50

2 5102550 100 200 Return Period 0 -3-2-10123456 Reduced variate

Hydrometric station 24082

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Appendix G - Catchment boundary discrepancies

The data used to assess the catchment discrepancies is provided to OPW using the Sharepoint file sharing system.

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Appendix H - Gauging station summary sheets

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Appendix I - Historical flood risk review details

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Where When Magnitude Impact Estima Flood ted Ref Grid Ranking Quality River Basin Tributary APSR Location Year Month Day Peak level Rainfall Flow Flood Extent Flooding mechanism Any damage caused AEP Source Date Authenticity Ref Code

CAR 03 ADARE

Road between External town and station Engineer flooded. No further Embankments breached, visiting area location detail Breached embankment. inundated agricultural land, Engineer with local 03-1a Maigue Maigue Adare given. - 1946 Land & road Low neap tides. road flooded. 4 report floodsmap 01/12/1946 Engineers. 3

NO DATA Limerick 03-1b ATTACHED 1946 August 12 4 Leader floodsmap 17/08/1946 -

NO DATA Evening 03-1c ATTACHED 1946 August 11 4 Echo (Cork) floodsmap 13/08/1946 -

NO DATA Evening 03-1d ATTACHED 1946 August 11 4 Echo (Cork) floodsmap 14/08/1946 -

NO DIRECT RELEVANT Cork 03-1e INFO. 1946 August 11 Heavy rain 4 Examiner floodsmap 15/08/1946 -

NO DIRECT RELEVANT Guardian 03-1f INFO. 1946 August 11 4 (Nenagh) floodsmap 17/08/1946 -

NO DIRECT RELEVANT 11/ Limerick 03-1g INFO. 1930 January 12 ? Chronicle floodsmap 14/01/1930 -

Photocopy of levels from notebook. Location and OPW 03-2a Maigue Maigue Adare Adare - 1999 January date unclear. 3 Mungret floodsmap 07/01/1999 2

NO DIRECT RELEVANT INFO - Limerick 03-2b CROOM - - - Leader floodsmap 09/01/1999 REFER TO REPORT 27/02/1996 03-3a ? 1997 February 10 N21 Tidal N21 flooded - OPW memo floodsmap 10/02/1997 3 Overtopping of embankment, flooding the road, a national primary route. Embankment in Overtopping embankment. many instances in excess of Report to Tide Level of 6.89mOD High tide due to low 300mm below design crest Regional 03-4a Maigue Maigue Adare Adare - 1995 January (22.6ft) @ Adare Road barometric pressure. of 24ft OD. 5 Engineers floodsmap 09/02/1995 3

Reports Only mentioned from Limerick. Adare is Land waterlogged in parts of Regional not specifically the Maigue catchment. Hydrometric 03-4b Maigue Maigue Adare mentioned - 1995 January Land & road Road flooding. 5 Technicians floodsmap 07/02/1995 Other 3

Photographs of flooding. Decemb Location OPW Dublin 03-5a Maigue Maigue Adare - 1973 er 1 unclear. 1 Hatch St floodsmap 01/12/1973 2

Undated photograph of flooding. Likely to be Station Location OPW 03-6a Maigue Maigue Adare Road? - - unclear. - Mungret floodsmap 2

Undated photograph of OPW 03-6b Maigue Maigue Adare Adare Bridge - - flooding. - Mungret floodsmap 3

Undated Photograph of OPW 03-6c Maigue Maigue Adare Station Road - - flooding. - Mungret floodsmap 3

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Where When Magnitude Impact Estima Flood ted Ref Grid Ranking Quality River Basin Tributary APSR Location Year Month Day Peak level Rainfall Flow Flood Extent Flooding mechanism Any damage caused AEP Source Date Authenticity Ref Code

Level data based on flood Station Rd area affected by OPW 03-6d Maigue Maigue Adare Station Road - 1999 January 7 debris marks ~10.40m? flooding. 3 Mungret floodsmap 2

OPW 01/ Mungret 03-6e Maigue Maigue Adare Road - 2002 February 02 Combined tidal and fluvial 150mm of road flooding. 6 Memo floodsmap - 3

Land near Adare Station, Limerick- Tarbert road west Breached left embankment Land near Adare Station, of Ferry Bridge, Map shows the a short distance below the Limerick-Tarbert road west townland of Land, Limerick-Tarbert extent of Railway Bridge at Adare of Ferry Bridge, townland of OPW Dublin 03-6f Maigue Maigue Adare Islandea. - - Rd, Islandea townland flooding. Station. Islandea flooded. - Hatch St floodsmap - 3

Doc Ref 2A showing Adare flooding is not Minute of attached within Combined tidal and Meeting 03-6g Maigue Maigue Adare Station Road - - the doc. rainfall/runoff - Limerick CC floodsmap 14/03/2005 4

Undated photograph and Curragh Bridge location map of OPW 03-7a Maigue Maigue Adare Islandea - - flooding. - Mungret floodsmap - 3

Undated photographs of OPW 03-7b Maigue Maigue Adare Islandea - - flooding. - Mungret floodsmap - 3

CAR 04 ASKEATON freque ncy one or Deel overflows on left bank, two feeds into a stream to the times west of L1236 and per OPW Flood factory car park factory car park overflows before draining Factory car park and L1236. annu Mapping 04 Deel Deel Askeaton and L1236 - - and L1236 back into Deel. No premises flooded. - m. Phase 1 floodsmap 12/04/2005 4

CAR 09 BALLYLONGFORD

Kerry STW were submerged High tide and overtopped of causing a backflow in pipe High Tide 6.3mOD. embankment on the and back up toilets in some "Highest tide" for 50 years northern side of the bridge. houses. Street drainage according to locals. Tide No flap valves on outfalls connected to sewage level reached the where some houses with no system also backed up. Engineers 9-1a, underside of the bridge. 2 Kerry STW, sewage system connected Street flooded and some 10 report OPW 3a Ballyline Ballyline Ballylongford Kerry STW - 2002 February 1 to 3ft (street flooding). street to. houses flooded. 1 Mungret floodmaps 26/04/2002 3

9-1b, OPW 3b Ballyline Ballyline Ballylongford - 2002 February Tidal c. 10? properties affected 1 Mungret floodmaps 15/02/2002 3

OPW Mungret memo - Flood LIS01/ history 9-1c Ballyline Ballyline Ballylongford Carrig Island 769 2001 August 21 ? database floodmaps 07/10/2003 4

OPW Mungret memo - Flood Land Commission LIS01/ Decemb history 9-1c Ballyline Ballyline Ballylongford Embankment 1584 2001 er 7 ? database floodmaps 08/10/2003 4

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Where When Magnitude Impact Estima Flood ted Ref Grid Ranking Quality River Basin Tributary APSR Location Year Month Day Peak level Rainfall Flow Flood Extent Flooding mechanism Any damage caused AEP Source Date Authenticity Ref Code

OPW Mungret memo - Flood Land Commission LIS02/ history 9-1c Ballyline Ballyline Ballylongford Embankment 1993 2002 March 8 ? database floodmaps 09/10/2003 4

OPW Mungret memo - Flood Land Commission LIS02/ history 9-1c Ballyline Ballyline Ballylongford Embankment 2104 2002 April 8 ? database floodmaps 10/10/2003 4

Only mentioned 9-1d, Ballylongford but 3d Ballyline Ballyline Ballylongford no details given. - 2002 February 1 2 Irish Times floodmaps 06/02/2002 -

Photograph of Gortnacooka flood extent - 9-2a Ballyline Ballyline Ballylongford Bridge - 2004 January 15 road & land ? Kerry CC floodmaps 15/01/2004 2

Photograph of Gortnacooka flood extent - 9-2b Ballyline Ballyline Ballylongford Bridge - 2004 January 15 road & land ? Kerry CC floodmaps 15/04/2004 2

At least 12 houses at Bridge St flooded up to window cill High tide with rainfall runoff, level. R551 impassable. LA wind direction and low water treatment plant was pressure. It is not known flooded during last event but Large scale map whether the poor state of remedial works safeguard it of village with the river channel of Ballyline in this event. Probably the OPW Flood 9-2c, Probably the "worst" flood area (NOT River helps or hinders the "worst" flooding in Kerry (at Mapping 3c Ballyline Ballyline Ballylongford Bridge St - 2002 January 6 flooding problem. PROVIDED) flooding. time of minutes). 1 Phase 1 floodmaps 01/12/2000 4 R552 is flooded and impassible two or three Rainfall /Runoff and poor times per yr. Max depth 900 state of the river channel to 1200mm. No houses Photographs and exaverbated by tide. affected. (Some flooding at OPW Flood 9-2c, Gortnacooka (NOT Restriction of bridge may be O'Brien's Bridge on a minor Mapping 3c Ballyline Ballyline Ballylongford Bridge - 2002 January 6 900 to 1200mm on R552 PROVIDED) a contributory factor. road also). 1 Phase 1 floodmaps 01/12/2000 4 Farmer from Carrig Island claimed that he stood to Cork 9-3d Ballyline Ballyline Ballylongford Carrig Island - 1990? Carrig Island lose 15 acres of land - Examiner floodmaps 17/02/1990 -

NO DIRECT RELEVANT INFO. TRALEE Decemb 01/ 9-3f ONLY 1973 er 02 Kerryman floodmaps 07/12/1973 -

NO DATA 9-3g ATTACHED Kerryman floodmaps 07/12/1973 - Flooded streets of 2ft depth at Street of Ballylongford up to 2ft 9-3h Ballyline Ballyline Ballylongford Ballylongford - 1961 October 22 Ballylongford Streets High tide depth. 4 Kerryman floodmaps 28/10/1961 - Flooded a number of houses, streets with slates Intense storm - high tide flying and trees falling. "one 9-3i Ballyline Ballyline Ballylongford Ballylongford - 1927 October 28 Houses, streets and gale of the worst in memory". 3 Kerryman floodmaps 05/11/1927 -

CAR 20 CHARLEVILLE

NO DATA 20 ATTACHED Houses flooded at Smith's Houses on Smith's Lane (kitchens & rooms Lane, Baker's were flooded), Baker's Lane Lane and Clanchy & Clanchy Terrace. Terrace flooded. Agricultural land damaged. Road into town Roads leading to the town Cork 03-1e Maigue Maigue Charleville flooded. 1946 August 11 Heavy rain were flooded. Examiner floodsmaps 15/08/1946 -

CAR 22 CLARINA

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Where When Magnitude Impact Estima Flood ted Ref Grid Ranking Quality River Basin Tributary APSR Location Year Month Day Peak level Rainfall Flow Flood Extent Flooding mechanism Any damage caused AEP Source Date Authenticity Ref Code

Undated photograph of flooding. Location OPW 22-1a Maigue Maigue Clarina - unknown. - Mungret floodmaps - 3

Undated photograph of flooding. Location OPW 22-1b Maigue Maigue Clarina - unknown. - Mungret floodmaps - 3

Undated photograph of flooding. Location OPW 22-1c Maigue Maigue Clarina - unknown. - Mungret floodmaps - 3

Map showing Septemb extent of OPW 22-1d Maigue Maigue Clarina - 1992 er flooding 1 ft depth of flooding 1 Mungret floodmaps 15/09/1992 3

One event in recent Water travelled from North OPW Flood 22-2a, years. Exceptional West, across Ballybrown Flooded a number of Mapping 3a Maigue Maigue Clarina Clarina Village - - rainfall. Houses Rd, through village houses. - Phase 1 floodmaps 14/03/2005 4 High tide flows through bridge side wall and over No houses affected. Area the embankment flooded is over a length of OPW Flood 22-2a, Toe of downstream of the bridge 700 to 800m at toe of Mapping 3a Maigue Maigue Clarina Massey's Bridge - - Tidal embankment on the RH bank. embankment. - Phase 1 floodmaps 15/03/2005 4

CAR 24 CROOM

Photographs of Gauge reader who lives at Report 24-1a, 05/ 2.82m (19.866 Poolbeg flooding at the bridge stated that water OPW 2a Maigue Maigue Croom - 1986 August 06 Datum) gauge & allyway. had not entered her kitchen. 2 Headford floodmaps - 2

24-1a, Decemb 2.86m (19.906 Poolbeg 2a Maigue Maigue Croom - 1983 er Datum) 1 2

24-1a, Decemb 2.28m (20.307 Poolbeg 2a Maigue Maigue Croom - 1973 er Datum) 3 2

Cappamore (not Limerick 24-1b Maigue Maigue Croom relevant?) - 1986 August 5 Leader 09/08/1986 -

Cappamore (not Limerick 24-1c Mulcair? Mulcair? Croom? relevant?) - 1986 August 5 Leader 16/08/1986 -

Newport, Ballymackeogh (not relevant?) - Guardian 24-1d Mulcair? Mulcair? Croom? No info attached - 1986 August 5 (Nenagh) 16/08/1986 - C1/31/ Flooding along Croom-Bruff 4/2 & Road (along C1/31/4/2) and Report C1/31/ C1/31/4/2 & north of the road (along OPW 24-2b Maigue Maigue Croom 4 1986 August 5 C1/31/4 C1/31/4). 2 Headford floodmaps 3

Undated photograph of 24-3a Maigue Maigue Croom Caherass - flooding floodmaps 3

Undated photograph of 24-3b Maigue Maigue Croom Caherass - flooding floodmaps 3

Undated photograph of 24-3c Maigue Maigue Croom Caherass - flooding floodmaps 3

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Where When Magnitude Impact Estima Flood ted Ref Grid Ranking Quality River Basin Tributary APSR Location Year Month Day Peak level Rainfall Flow Flood Extent Flooding mechanism Any damage caused AEP Source Date Authenticity Ref Code

Flooding caused by the blockage or lack of discharge capacity of a culverted section Map showing discharging into channel No. Repot OPW 24-3d Maigue Maigue Croom Caherass - - area affected C1/19/2 Mungret floodmaps 28/04/1995 4

Map showing Minutes of source of meeting 24-4a Maigue Maigue Croom Dollas - flooding Heavy rain Limerick CC floodmaps 04/2005 4

Undated RH bank d/s of photograph of OPW 24-5a Maigue Maigue Croom road bridge - flooding Mungret floodmaps - 3

Undated photograph of OPW 24-5b Maigue Maigue Croom D/s of road bridge - flooding Mungret floodmaps - 3

Undated RH bank u/s of photograph of OPW 24-5c Maigue Maigue Croom road bridge - flooding Mungret floodmaps - 3

Undated LH bank u/s of photograph of OPW 24-5d Maigue Maigue Croom road bridge - flooding Mungret floodmaps - 3

Undated LH bank d/s of photograph of OPW 24-5e Maigue Maigue Croom road bridge - flooding Mungret floodmaps - 3 "Worst flood in living 15 houses flooded. memory". Worse than Banogue (Croom) Cremery Cork Newspaper 03-1e Maigue Maigue Croom 1946 August 11 1916. Maigue overflowed banks was flooded. Examiner floodsmap 15/08/1946 report. -

Limerick 03-2b Maigue Maigue Croom 1990 February Houses flooded. Leader floodsmap 09/01/1999 -

Limerick 03-2b Maigue Maigue Croom 1995 January Houses flooded. Leader floodsmap 09/01/1999 -

Limerick 03-2b Maigue Maigue Croom 1995 February Houses flooded. Leader floodsmap 09/01/1999 -

Limerick 03-2b Maigue Maigue Croom 1995 March Houses flooded. Leader floodsmap 09/01/1999 -

Limerick 03-2b Maigue Maigue Croom 1997 August Houses flooded. Leader floodsmap 09/01/1999 -

Within 6 ft of top of new Decemb bridge. Up to windows of Limerick 03-2b Maigue Maigue Croom 1998 er 29 Riverside properties. Overflowed defences Houses flooded. Leader floodsmap 09/01/1999 -

CAR 25 DROMCOLLIHER

Ahavarragh Flood Study 25-1a, and Report 2b Deel Carroward Dromcolliher Pike St - 1984 January 16 Pike St Rain and snow House at Pike St flooded. ? OPW Dublin floodmaps 12/1997 2

Ahavarragh Flood Study 25-1a, and Houses not flooded. Roads Report 2b Deel Carroward Dromcolliher - 1986 January 22 Roads flooded. ? OPW Dublin floodmaps 12/1998 2

Ahavarragh Flood Study 25-1a, and Houses not flooded. Roads Report 2b Deel Carroward Dromcolliher - 1986 July 28 Roads flooded. ? OPW Dublin floodmaps 12/1999 2

Ahavarragh Flood Study 25-1a, and houses, church Houses and church flooded. Report 2b Deel Carroward Dromcolliher Church - 1986 August 6 & roads Roads flooded. ? OPW Dublin floodmaps 12/2000 2

Ahavarragh Flood Study 25-1a, and Houses not flooded. Roads Report 2b Deel Carroward Dromcolliher - 1986 August 25 roads flooded. ? OPW Dublin floodmaps 12/2001 2

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Where When Magnitude Impact Estima Flood ted Ref Grid Ranking Quality River Basin Tributary APSR Location Year Month Day Peak level Rainfall Flow Flood Extent Flooding mechanism Any damage caused AEP Source Date Authenticity Ref Code

Ahavarragh Flood Study 25-1a, and Houses not flooded. Roads Report 2b Deel Carroward Dromcolliher - 1988 January 22 Roads flooded. ? OPW Dublin floodmaps 12/2002 2

Ahavarragh Flood Study 25-1a, and Houses not flooded. Roads Report 2b Deel Carroward Dromcolliher - 1988 February 1 Roads flooded. ? OPW Dublin floodmaps 12/2003 2 Ahavarragh Flood Study 25-1a, and Houses flooded at Pike St. Report 2b Deel Carroward Dromcolliher Pike St - 1988 October 11 houses & roads Roads flooded. ? OPW Dublin floodmaps 12/2004 2

Ahavarragh Flood Study 25-1a, and Houses not flooded. Roads Report 2b Deel Carroward Dromcolliher - 1988 October 21 Roads flooded. ? OPW Dublin floodmaps 12/2005 2

Ahavarragh Flood Study 25-1a, and Houses not flooded. Roads Report 2b Deel Carroward Dromcolliher - 1989 January 11 Roads flooded. ? OPW Dublin floodmaps 12/2006 2

Ahavarragh Flood Study 25-1a, and Houses not flooded. Roads Report 2b Deel Carroward Dromcolliher - 1990 February 6 Roads flooded. ? OPW Dublin floodmaps 12/2007 2

Ahavarragh Flood Study 25-1a, and Decemb Houses not flooded. Roads Report 2b Deel Carroward Dromcolliher - 1990 er 28 Roads flooded. ? OPW Dublin floodmaps 12/2008 2

Ahavarragh Flood Study 25-1a, and Novemb Report 2b Deel Carroward Dromcolliher - 1991 er 12 Roads Roads flooded. ? OPW Dublin floodmaps 12/2009 2

Ahavarragh Flood Study 25-1a, and Report 2b Deel Carroward Dromcolliher - 1993 January 17 Roads Roads flooded. ? OPW Dublin floodmaps 12/2010 2

Ahavarragh Flood Study 25-1a, and Septemb Report 2b Deel Carroward Dromcolliher - 1993 er 9 Roads Roads flooded. ? OPW Dublin floodmaps 12/2011 2

Ahavarragh Flood Study 25-1a, and Decemb Report 2b Deel Carroward Dromcolliher - 1993 er 8 Roads Roads flooded. ? OPW Dublin floodmaps 12/2012 2

Ahavarragh Flood Study 25-1a, and Minor flooding - roads Report 2b Deel Carroward Dromcolliher - 1994 January 14 Roads flooded. ? OPW Dublin floodmaps 12/2013 2

Ahavarragh Flood Study 25-1a, and Report 2b Deel Carroward Dromcolliher - 1994 January 15 Roads Roads flooded. ? OPW Dublin floodmaps 12/2014 2

Ahavarragh Flood Study 25-1a, and Decemb Report 2b Deel Carroward Dromcolliher - 1994 er 27 Roads Roads flooded. ? OPW Dublin floodmaps 12/2015 2

Ahavarragh Flood Study 25-1a, and Decemb Report 2b Deel Carroward Dromcolliher - 1994 er 30 Roads Roads flooded. ? OPW Dublin floodmaps 12/2016 2

Ahavarragh Flood Study 25-1a, and Report 2b Deel Carroward Dromcolliher - 1995 January 16 Roads Roads flooded. ? OPW Dublin floodmaps 12/2017 2 Ahavarragh Flood Study 25-1a, and Report 2b Deel Carroward Dromcolliher - 1995 January 17 Roads Roads flooded. ? OPW Dublin floodmaps 12/2018 2 Ahavarragh Flood Study 25-1a, and Report 2b Deel Carroward Dromcolliher - 1995 January 25 Roads Roads flooded. ? OPW Dublin floodmaps 12/2019 2

Ahavarragh Flood Study 25-1a, and Report 2b Deel Carroward Dromcolliher - 1995 February 22 Roads Roads flooded. ? OPW Dublin floodmaps 12/2020 2

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Where When Magnitude Impact Estima Flood ted Ref Grid Ranking Quality River Basin Tributary APSR Location Year Month Day Peak level Rainfall Flow Flood Extent Flooding mechanism Any damage caused AEP Source Date Authenticity Ref Code

Ahavarragh Flood Study 25-1a, and Houses & Report 2b Deel Carroward Dromcolliher Church - 1995 June 30 church Houses and church flooded. ? OPW Dublin floodmaps 12/2021 2 Ahavarragh Flood Study 25-1a, and Report 2b Deel Carroward Dromcolliher - 1997 July 12 houses & roads Houses and roads flooded. ? OPW Dublin floodmaps 12/2022 2

Flood estimation Heavy rainfall with Houses and roads flooded. provided. insufficient capacity of the Eastern village - several (Catchment river channel. Overloaded houses in Pike St area 1 - 1:50 = combined sewers, raw looded to 0.5m deep. 5.5m3/s, sewage overflowed onto Flooding of Pike St and 1:100 = streets and houses. Pound St. Western village - 6.3m3/s; Bridges and culverts backed Ahavarraga Stream Flood levels along Pike St Catchment Map showing up along Ahavarraga overflowed causing flooding and Pound St ranges btw 57.5mm 2 - 1:50 = properties Stream. Also, major to roads in the vicinity of Ahavarragh 93.50 to 117.81mOD of rainfall 2.9m3/s, affected and the channel capacity problem church. Lands flooded. Flood Study 25-1a, and Pike St, Church, (See table in the report for in 4hr 1:100 = associated downstream of Dromcolliher Refer to Appendix 2 of the Report 2b Deel Carroward Dromcolliher Pound St - 1997 August 26 various level information). period. 3.4m3/s) depths. causing a backwater effect. report. 1 1:50 OPW Dublin floodmaps 12/2023 2 Flooding caused by insufficient capacity of the Carroward Stream. Culverted crossings (especially the County Bridge on Liscarrol Rd (R522) and culvert under Pound St) restrict the flow and surcharging causing road flooding on a regular Dromcollihe basis. Insufficient capability r Localised of channel downstream of Flood Relief Ahavarragh the Ahavarragh River Work 25-1b, and Liscarrol Rd confluence with the Feasibility 2a Deel Carroward Dromcolliher (R522), Pound St - 1997 August 26 Carroward Stream. 1 1:40 Study floodmaps 10/1999 3

Ahavarragh Village flooded 3 times in River Deel and Village & sewage Village & 1997 and sewage plant was Dromcollihe 25-1c Deel Carroward Dromcolliher plant - 1997 sewage plant flooded. r Flooding floodmaps 25/11/1997 3

Ref 44-2a stated "there was a serious flooding problem Ahavarragh in Dromcolliher but remedial OPW Flood and works was completed 3 year Mapping 44-2a Deel Carroward Dromcolliher - prior & problem eliminated. - Phase 1 floodmaps 25/04/2005 4

CAR 29 FOYNES

High tide overtopping embankment (level 19' OD Resident 19.62' OD (5.98m). Road (5.79m) to 22.53' OD Engineer flooded (road level 13.6' (6.87m)). Possibly flooding Report OD (4.39m) to 14.4' OD via gullies and surface water Domestic and commercial OPW 29-1a Other Foynes Foynes - 2002 February 1 (4.15m)). Properties drains without flap valve. property flooding. 1 Mungret floodmaps 18/09/2002 1

Heavy rain and capacity of stream along Main St is 29-1b, Main Street & unable to cope with the flow N69 at Dernish and a Limerick CC 5a Other Foynes Denish - 2002 January 23 N69, properties causing backing up of water number of premises flooded 2 Letter floodmaps 25/02/2002 2

Overtopped quay wall in the "more serious flooding" harbour area and water than 23/01/2002 event. flowed across railway line Tide level 6.28m into the rear of a number of 29-1b, (compared to predicted High tide with high floods in preperties on Main St Limerick CC 5a Other Foynes Main Street - 2002 February 1 level of 5.4m) Properties the Shannon. causing severe flooding. 1 Letter floodmaps 25/02/2002 2

c. 20? Properties affected to 29-1c Other Foynes - 2002 February Properties Tidal a depth of <300mm 3? 1:5? OPW memo floodmaps 15/02/2002 3 29-1c Other Foynes - 1997? February OPW memo floodmaps 15/02/2002 3

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Where When Magnitude Impact Estima Flood ted Ref Grid Ranking Quality River Basin Tributary APSR Location Year Month Day Peak level Rainfall Flow Flood Extent Flooding mechanism Any damage caused AEP Source Date Authenticity Ref Code Some flooding of agricultural land to the east of Foynes due to High tide - flow out across overtopping of a Land the port entrance and Commission Embankment. thence up the village. May Overtopping at one location be an element of floodwater caused the capacity of the Agricultural land to backing up the surface d/s drainage system to be 29-1d Other Foynes the east of Foynes - - Agricultural land water sewers exceeded. OPW memo floodmaps 05/02/2002 4

Spring tide rose 1.8m higher than predicted due A shop, a pub and a number 29-1e Other Foynes Foynes - 2002 February 1 to strong winds Properties Heavy rainfall & high tide of houses were flooded. 1 Irish Times floodmaps 05/02/2005 - 29-1f Other Foynes Foynes - 2002 February 1 Flooding in Foynes. Irish Times floodmaps 06/02/2002 -

Fluvial with tide locked condition. Previous storage area is occupied by residential development At least 4 dwellings and 2 29-2a Other Foynes Foynes - 2005 January 8 Properties according to a resident. businesses 5 OPW memo floodmaps 25/01/2005 3 Proposed partial stream 29-3a, "worst case flooding" in N69 (Flood map Fluvial with tide locked Limerick CC divertion - 5c Other Foynes N69, Corgrigg - 1995 February recent memory not attached) condition. N69 flooded for days 4? Letter floodmaps 23/07/2003 carried out? 4 Main Foynes to Limerick , two houses along N69 High tides, with very intense flooded. Road and a rainfall and south westerly commercial garage OPW memo 29-4a, Properties & winds and lack of channel premises also flooded in & Limerick 6a Other Foynes Shanagolden area - road capacity Shanagolden area. - CC letters floodmaps 18/05/1999 3

6 properties and N69 shown Limerick CC 29-5b Other Foynes Corgrig - - N69 & properties as flooded. - map floodmaps 07/2003 3

Map showing 29-5d, Durnish, Corgrig locations of Heavy rain and storm/tidal Limerick CC 6b, 7a Other Foynes and Robertstown - flooding flooding - map floodmaps 04/2005 4

Rainfall/runoff combined Partial or complete blockage with inadequate culvert of the N69 and flooding of OPW Flood 29-5e, capacity/storage and front gardens to houses and Mapping 6c Other Foynes N69 - 2005 January N69 flooding due to high tides rarely flood the houses. 5 Phase 1 floodmaps 12/04/2005 4

OPW Flood 29-5e, Mapping 6c Other Foynes - 2002 January 23 2 Phase 1 floodmaps 13/04/2005 4

OPW Flood 29-5e, Mapping 6c Other Foynes - 1995 February 23 4? Phase 1 floodmaps 14/04/2005 4

Tide overflows the port quay wall, flows south westward across the railway line and into the rear of a number of properties along main street causing severe flooding to OPW Flood 29-5e, Foynes Main Properties & High tides, low pressure & premises. Also flood main Mapping 6c Other Foynes Street, N69 - 2002 February 1 roads strong south westerly winds street and N69. 1 Phase 1 floodmaps 15/04/2005 4

NO Minutes of RELEVANT meeting 29-7b INFO - Cork CC floodmaps 27/04/2005 4

Flooding in the Railway Rd area in particular. Foynes Shannon, brigade was called out to Abbey / help pumping operations at Limerick 37-25b Shannon Tidal Limerick City Foynes 1995 January 30 Heavy rain the Grotto end of Foynes. Chronicle floodmaps 31/01/1995 -

CAR 32 KILDINO NEW

NO DATA/SITE FOUND FROM 32 DATABASE

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Where When Magnitude Impact Estima Flood ted Ref Grid Ranking Quality River Basin Tributary APSR Location Year Month Day Peak level Rainfall Flow Flood Extent Flooding mechanism Any damage caused AEP Source Date Authenticity Ref Code

CAR 35 KILMALLOCK

NO DATA 35 ATTACHED Some of the roads were flooded, the house at the end of Wolle Tune St, Cork Newspaper 03-1e Maigue Maigue Kilmallock 1946 August 11 Rainstorm Kilmallock was flooded. Examiner floodsmap 15/08/1946 report. -

CAR 44 NEWCASTLE WEST Predicte d 79.8mm, Report on (7 hrs >1:25 2008 duration) 0yrs Summer Newcastle Newcastle West , 84.9mm (0.4% Rainfall in 44-1a Deel Arra West town - 2008 August 1 (14 hrs) 1 ) Ireland floodmaps 12/2008 1

Properties, 143 residential and 87 WTW, WWTP, commercial properties, 48.71 to 57.23mOD (d/s ESB substation WTW, WWTP, ESB >1:21 Detailed of bridge of Tears to 85.9mm & roads. (Flood "Localised flooding" due to substation and several 0yrs flooding Newcastle Newcastle West street entrance @ average Map (Figure presistent rainfall with roads in the town were (0.47 Flooding information in 44-1b Deel Arra West town - 2008 August 1 Bllygowan plant) rainfall. 8.1)) saturated catchment flooded. 1 %) Report, JBA floodmaps 01/08/2008 report 1 Station 24030 Danganbeg (located on Deel u/s): Peak @ 03.00 with debris Newcastle Newcastle West mark ~ 4.1m (gauge 44-1c Deel Arra West town - 2008 August 1 reading 3.63m) 64.9m3/s 1 EPA Report floodmaps 05/08/2008 2

Station 24029 Inchirourke More (located on Deel Newcastle Newcastle West d/s): Peak @ 04.15 with 44-1c Deel Arra West town - 2008 August 2 level of 2.54m 46m3/s 1 EPA Report floodmaps 05/08/2008 2

Station 24025 Cantogher (located on tributary to Newcastle Newcastle West Maigue): Peak @ 00.45 Outside 44-1c Deel Arra West town - 2008 August 1 with level of 2.17m rating curve 1 EPA Report floodmaps 05/08/2008 2

Newcastle Newcastle West Station 24029 Inchirourke 44-1c Deel Arra West town - 1995 February 3 More: Peak level of 2.56m 47.7m3/s 2 EPA Report floodmaps 05/08/2008 2

Newcastle Newcastle West Decemb Station 24029 Inchirourke 44-1c Deel Arra West town - 1998 er 30 More: Peak level of 2.56m 47.6m3/s 3 EPA Report floodmaps 05/08/2008 2

Range between 47.50 to Lower Maiden St, 58.16mOD from Lower Flood Map Newcastle New Rd to South Maiden St, New Rd to OPW 44-1d Deel Arra West Quay - 2008 August 1 South Quay 1 Mungret floodmaps 01/08/2008 3

Newcastle Video footage 44-1e Deel Arra West - - Other floodmaps 01/08/2008 - not attached Main road (R520) between Killmallock and Newcastle West flooded and impassable and adjacent land flooded. Flooding has Minutes of Newcastle historically occurred every 1 meeting 44-2a Deel Arra West Main Road R520 - - Roads & land River Deel. to 3 yrs. - Limerick CC floodmaps 25/04/2005 4

Minutes of Newcastle Road impassable roughly 2 meeting 44-2a Deel Arra West Grange - Road River Deel. times per annum. - Limerick CC floodmaps 25/04/2005 4

Map showing Minutes of Newcastle locations of flood meeting 44-2b Deel Arra West Newcastle West - hazard. - Limerick CC floodmaps 21/06/2005 4

Map showing the Newcastle type of flooding 44-3 Deel Arra West Newcastle West - cause Heavy rain - Limerick CC floodmaps 04/2005 4

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Where When Magnitude Impact Estima Flood ted Ref Grid Ranking Quality River Basin Tributary APSR Location Year Month Day Peak level Rainfall Flow Flood Extent Flooding mechanism Any damage caused AEP Source Date Authenticity Ref Code

CAR 50 RATHKEALE Flooding in Deel Valley u/s of Rathkeale at Deel Bridge & at Balliniska - Bunoke. OPW Deel Bridge & 09- Rainfall - 43mm (~96hrs) Losts of rain during Dec & Duration of flooding ~ 24 Hydrometric 50-1a Deel Deel Rathkeale Balliniska - Bunoke - 1969 January 12 @ Deel Jan & saturated catchment hours. 3 Report floodmaps 07/02/1969 3 Flooding in Deel Valley u/s of Rathkeale at Deel Bridge & at Balliniska - Bunoke. OPW Deel Bridge & Decemb 23- Rainfall - 62mm (~48hrs) Losts of rain during Dec & Duration of flooding ~ 24 Hydrometric 50-2a Deel Deel Rathkeale Balliniska - Bunoke - 1968 er 24 @ Deel Jan & saturated catchment hours. 1 Report floodmaps 07/02/1969 3 Flooding in Deel Valley u/s of Rathkeale at Deel Bridge. OPW Decemb 11- Rainfall - 56mm (~72hrs) Losts of rain during Dec & Duration of flooding ~ 24 Hydrometric 50-3a Deel Deel Rathkeale Deel Bridge - 1968 er 13 @ Deel Jan & saturated catchment hours. 2 Report floodmaps 07/02/1969 3

Graigue between Rathkeale & Ballingarry - land flooded on average once every 4/5 Flooding caused by feeder yrs. Area affected is btw the Minutes of streams feeding the Deel R518 and L1213. Roads not meeting 50-4a Deel Deel Rathkeale Graigue - - Land & Roads backing up. flooded. - Limerick CC floodmaps 12/04/2005 4

Minutes of meeting 50-5a Deel Deel Rathkeale Ballinlyny - - Flooding map Heavy rain Limerick CC floodmaps 04/2005 4

Knockaunavad - NW of Minutes of Rathkeale - lands to east of meeting 50-6a Deel Deel Rathkeale Knockaunavad - - L1219 flooded every winter. Limerick CC floodmaps 12/04/2005 4

Minutes of meeting 50-7a Deel Deel Rathkeale Rathkeale - - Flooding map Heavy rain Limerick CC floodmaps 04/2005 4

TD_GNRL_0120_V1_0_JAC_HydroAssmtUoM24_120704.doc

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study

Gauging Station Information Sheet

24001 – MAIGUE AT CROOM

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Flow Date Easting: 151274 Northing: 141001 Year (m 3/s) 1946 Catchment: Maigue Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 770.20 km 2 1949 1950 1951 QMED (gauged): 118.44 m 3/s AREA (FS U): 770.23 km 2 1952 1953 N/A 26/02/1954 QMED (FSU): 111.96 m 3/s SAAR (FSU): 941.30 1954 N/A 01/01/1955 1955 N/A 27/09/1956 QMED (predicted): 120.08 m3/s FARL (FSU): 1.00 1956 N/A 01/01/1957 1957 N/A 11/02/1958 BFIsoils (FSU): 0.53 S1085: 1.97 1958 N/A 20/12/1958 1959 N/A 08/12/1959 URBEXT: 0.66 ARTDRAIN2: 51.00 1960 N/A 04/12/1960 1961 N/A 16/01/1962 DRAIND: 1.10 1962 N/A 09/02/1963 1963 N/A 19/03/1964 Comments: Automated velocity- area station installed in 1953. Natural channel with a 1964 N/A 13/12/1964 gravel shoal as low flow control. Considerable scatter at low end due to unstable control. 1965 N/A 10/12/1965 1966 N/A 23/02/1967 1967 N/A 17/10/1967 Nearby APSRs : To be confirmed 1968 N/A 10/01/1969 1969 N/A 17/02/1970 1970 N/A 29/11/1970 Jacobs Rating Review required : YES OPW Station Classification: A2 1971 N/A 04/02/1972 1972 N/A 06/12/1972 Normalised Hydrographs 1973 N/A 01/12/1973 1974 N/A 25/01/1975 1975 N/A 30/01/1976 2 1976 N/A 23/12/1976 1.8 1977 61.8 04/02/1978 1978 109.3 08/12/1978 1.6 1979 114.6 26/12/1979 1.4 1980 140.8 02/11/1980 1981 105.0 14/07/1982 1.2 21/10/1988 1982 176.2 08/11/1982 16/12/1983 1 1983 192.5 16/12/1983 06/08/1986 1984 121.3 14/08/1985 0.8 01/02/1988 1985 190.9 06/08/1986 1986 173.1 08/12/1986 0.6

1987 178.2 01/02/1988 Flow(standardised by Qmed) 0.4 1988 213.7 21/10/1988 1989 171.6 06/02/1990 0.2 1990 109.3 28/12/1990 0 1991 106.6 25/11/1991 0 1 2 3 1992 105.2 30/09/1993 Time (days) 1993 130.7 15/01/1994 1994 161.2 09/03/1995 1995 130.7 07/01/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 151.8 05/08/1997 1997 132.2 17/10/1997 250 1998 163.6 30/12/1998 1999 106.6 25/12/1999 2000 148.0 06/11/2000 2001 109.3 23/01/2002 200 2002 95.8 27/11/2002 2003 91.8 14/11/2003 2004 107.9 29/10/2004 150 2005 108.6 21/05/2006 2006 99.1 03/12/2006 2007 107.9 10/01/2008 100 2008 118.4 10/01/2008 AMAX Flow (cumecs) 2009 112.1 19/11/2009

50 Length of AMAX series : 33 years 2 5 10 25 50 100 200 Return Period (yrs) NB: 1989 higher level than 1988 0 -2 -1 0 1 2 3 4 5 6 Reduced Variate

Last Updated: May 2011 Last saved by Jacobs Page 1 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study

Gauging Station Information Sheet

24002 – CAMOGE AT GRAY'S BR.

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Level Date Easting: 157932 Northing: 140276 Year (mOD) 1946 Catchment: Maigue Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 243.60 km 2 1949 1950 1951 QMED (gauged): N/A m 3/s AREA (FSU): 229.40 km 2 1952 1953 QMED (FSU): 23.49 m 3/s SAAR (FSU): 917.14 1954 1955 QMED (predicted): 34.10 m3/s FARL (FSU): 1.00 1956 1957 BFIsoils (FSU): 0.59 S1085: 1.68 1958 1959 URBEXT: 0.43 ARTDRAIN2: 60.00 1960 1961 DRAIND: 1.14 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : No OPW Station Classification: B 1971 1972 49.5 07/12/1972 Normalised Hydrographs 1973 49.9 03/12/1973 1974 49.5 27/01/1975 Chart not available 1975 49.4 01/02/1976 1976 49.3 19/02/1977 1977 N/A N/A 1978 48.7 11/12/1978 1979 48.6 07/08/1980 1980 49.0 27/05/1981 1981 49.1 14/07/1982 1982 49.3 08/11/1982 1983 49.3 06/02/1984 1984 49.1 01/12/1984 1985 49.0 06/08/1986 1986 49.1 09/12/1986 1987 49.2 01/02/1988 1988 49.3 12/10/1988 1989 49.6 07/02/1990 1990 48.9 29/12/1990 1991 48.9 26/11/1991 1992 48.9 14/01/1993 1993 49.1 17/12/1993 1994 49.4 23/02/1995 1995 49.3 11/02/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 49.0 07/08/1997 1997 49.1 19/11/1997 51 1998 49.0 17/11/1998 1999 49.2 26/12/1999 2000 49.4 07/11/2000 2001 49.2 26/02/2002 50 2002 49.0 28/11/2002 2003 48.9 15/11/2003 2004 49.2 08/01/2005 2005 49.0 13/01/2006 49 2006 49.1 08/12/2006 2007 49.1 11/01/2008 Level (mAOD) 2008 49.3 01/02/2009 2009 49.1 21/11/2009 48 Length of AMAX series : 37 years 2 5 10 25 50 100 200 Return Period 47 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 2 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24003 – LOOBAGH AT GARROOSE

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Level Date Easting: 155008 Northing: 127458 Year (mOD) 1946 Catchment: Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 129.20 km 2 1949 1950 1951 QMED (gauged): N/A m 3/s AREA (FSU): N/A km 2 1952 1953 QMED (FSU): N/A m 3/s SAAR (FSU): N/A 1954 1955 QMED (predicted): N/A m3/s FARL (FSU): N/A 1956 1957 BFIsoils (FSU): N/A S1085: N/A 1958 1959 URBEXT: N/A ARTDRAIN2: N/A 1960 1961 DRAIND: N/A 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : YES OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 1974 Chart not available 1975 1976 1977 1978 1979 1980 60.3 27/05/1981 1981 59.9 14/07/1982 1982 59.3 08/11/1982 1983 60.2 16/12/1983 1984 59.2 14/08/1985 1985 60.3 06/08/1986 1986 59.6 08/12/1986 1987 59.8 02/02/1988 1988 60.5 22/10/1988 1989 60.5 06/02/1990 1990 59.6 28/12/1990 1991 59.7 25/11/1991 1992 59.8 30/09/1993 1993 60.0 17/01/1994 1994 59.9 17/01/1995 1995 60.1 06/01/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 60.5 05/08/1997 1997 60.1 17/11/1997 61.0 1998 60.5 29/12/1998 1999 59.7 18/12/1999

2000 60.5 06/11/2000 60.5 2001 60.0 23/01/2002 2002 60.2 21/11/2002 2003 59.9 14/11/2003 60.0 2004 60.5 28/11/2004 2005 59.9 02/12/2005 59.5 2006 59.7 03/12/2006 2007 60.3 10/10/2008 AMAX AMAX Flow (cumecs) 2008 60.2 31/01/2009 59.0 2009 60.3 01/11/2009

58.5 Length of AMAX series : 30 years 2 5 10 25 50 100 200

Return Period 58.0 -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 3 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24004 – MAIGUE AT BRUREE

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Flow Date Easting: 155078 Northing: 130369 Year (m 3/s) 1946 Catchment: Maigue Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 242.10 km 2 1949 1950 1951 QMED (gauged): 53.44 m 3/s AREA (FSU): 242.13 km 2 1952 1953 38.9 25/01/1954 QMED (FSU): 50.63 m 3/s SAAR (FSU): 974.53 1954 33.8 01/01/1955 1955 49.1 26/09/1956 QMED (predicted): 45.80 m3/s FARL (FSU): 1.00 1956 43.1 01/01/1957 1957 36.3 03/08/1958 BFIsoils (FSU): 0.52 S1085: 3.31 1958 41.0 19/12/1958 1959 41.7 08/12/1959 URBEXT: 1.33 ARTDRAIN2: 34.00 1960 49.8 04/12/1960 1961 39.6 15/03/1962 DRAIND: 1.16 1962 30.2 08/03/1963 1963 37.6 19/03/1964 Comments: Automated velocity- area station installed in 1953. Natural channel with a 1964 62.4 13/12/1964 gravel shoal as low flow control. Considerable scatter at low end due to unstable control. 1965 68.9 17/11/1965 1966 41.0 23/02/1967 1967 29.0 17/10/1967 Nearby APSRs : To be confirmed 1968 99.7 10/01/1969 1969 29.0 20/01/1970 1970 31.6 19/11/1970 Jacobs Rating Review required : No OPW Station Classif ication: B 1971 30.5 15/01/1972 1972 32.2 17/02/1973 Normalised Hydrographs 1973 67.4 01/12/1973 1974 32.8 25/01/1975 1975 42.0 30/01/1976 2 1976 27.7 23/12/1976 1.8 1977 21.6 21/04/1978 1978 55.5 08/12/1978 1.6 1979 52.6 25/10/1979 1.4 1980 53.4 03/11/1980 1981 36.6 21/02/1982 1.2 06/02/1990 1982 61.1 08/11/1982 16/12/1983 1 1983 99.7 16/12/1983 30/12/1998 1984 47.9 14/08/1985 0.8 22/10/1988 1985 91.7 06/08/1986 1986 67.4 08/12/1986 0.6

1987 67.0 01/02/1988 Flow(standardised by Qmed) 0.4 1988 98.0 22/10/1988 1989 104.6 06/02/1990 0.2 1990 50.6 28/12/1990 0 1991 48.7 25/11/1991 0 1 2 3 1992 45.7 30/09/1993 Time (days) 1993 63.3 15/01/1994 1994 84.0 10/03/1995 1995 61.5 10/02/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 78.2 05/08/1997 1997 65.1 18/11/1997 120 1998 98.6 30/12/1998 1999 50.6 27/12/1999

2000 84.0 06/11/2000 100 2001 58.0 23/01/2002 2002 58.0 27/11/2002 2003 53.4 14/11/2003 80 2004 60.6 29/10/2004 2005 61.5 21/05/2006 60 2006 55.5 03/12/2006 2007 62.4 10/01/2008 AMAX AMAX Flow (cumecs) 2008 59.8 31/01/2009 40 2009 62.3 19/11/2009

Length of AMAX series : 57 years 20 2 5 10 25 50 100 200 Return Period 1959, 1960, 1963, 1964, 1967 -gauge 0 readers (rather than staff gauge) -2 -1 0 1 2 3 4 5 6 checked Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 4 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24005 – MORNINGSTAR AT ATHLACCA

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Flow Date Easting: 155782 Northing: 134290 Year (m 3/s) 1946 Catchment: Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 131.90 km 2 1949 1950 1951 QMED (gauged): 19.11 m 3/s AREA (FSU): N/A km 2 1952 1953 20.0 27/02/1954 QMED (FSU): N/A m 3/s SAAR (FSU): N/A 1954 18.8 01/01/1955 1955 14.0 25/03/1956 QMED (predicted): N/A m3/s FARL (FSU): N/A 1956 18.8 01/01/1957 1957 16.5 03/09/1958 BFIsoils (FSU): N/A S1085: N/A 1958 17.6 19/12/1958 1959 17.3 07/12/1959 URBEXT: N/A ARTDRAIN2: N/A 1960 21.0 04/12/1960 1961 13.9 16/03/1962 DRAIND: N/A 1962 16.6 09/02/1963 1963 23.7 20/03/1964 Comments: 1964 25.1 17/01/1965 1965 24.8 10/12/1965 1966 25.4 23/02/1967 1967 19.1 18/10/1967 Nearby APSRs : To be confirmed 1968 28.8 15/12/1968 1969 21.4 20/01/1970 1970 Jacobs Rating Review required : No OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 1974 Chart not available 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 Flood Frequency (EV1 with Gringorten plotting positions) 1996 1997 35 1998 1999 2000 30 2001 2002 25 2003

2004 20 2005 2006 2007 15 2008 AMAX Flow (cumecs) 2009 10

Length of AMAX series : 17 years 5 2 5 10 25 50 100 200 Return Period

Drainage scheme 1973 to 1980 0 -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 5 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24006 – MAIGUE AT CREGGANE

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Level Date Easting: 153408 Northing: 127284 Year (mOD) 1946 Catchment: Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 83.10 km 2 1949 1950 1951 QMED (gauged): N/A m 3/s AREA (FSU): N/A km 2 1952 1953 QMED (FSU): N/A m 3/s SAAR (FSU): N/A 1954 1955 QMED (predicted): N/A m3/s FARL (FSU): N/A 1956 1957 BFIsoils (FSU): N/A S1085: N/A 1958 1959 URBEXT: N/A ARTDRAIN2: N/A 1960 1961 DRAIND: N/A 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : YES OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 1974 Chart not available 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 Flood Frequency (EV1 with Gringorten plotting positions) 1996 1997 61 1998 60.2 30/12/1998 1999 59.7 22/12/1999 2000 60.2 06/11/2000 2001 59.8 23/01/2002 2002 59.8 27/11/2002 2003 59.7 14/11/2003 60 2004 60.2 28/10/2004 2005 59.8 22/05/2006 2006 59.6 03/12/2006 2007 60.0 10/01/2008 Level (mAOD)

2008 59.8 31/01/2009 59 2009 60.0 20/11/2009

Length of AMAX series : 12 years 2 5 10 25 50 100 200

Return Period 58 -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 6 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24008 – MAIGUE AT CASTLEROBERTS

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Flow Date Easting: 148000 Northing: 143779 Year (m 3/s) 1946 Catchment: Maigue Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 806.00 km 2 1949 1950 1951 QMED (gauged): 118.53 m 3/s AREA (FSU): 806.04 km 2 1952 1953 QMED (FSU): 119.13 m 3/s SAAR (FSU): 939.47 1954 1955 QMED (predicted): 121.69 m3/s FARL (FSU): 1.00 1956 1957 BFIsoils (FSU): 0.55 S1085: 2.14 1958 1959 URBEXT: 0.69 ARTDRAIN2: 52.00 1960 1961 DRAIND: 1.08 1962 1963 Comments: Automated velocity-area station installed and automated in 1973. Stable 1964 mud bed. Natural channel with none standard weir control. Seasonal weed growth. 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : YES OPW Station Classification: A2 1971 1972 Normalised Hydrographs 1973 1974 1975 N/A 30/01/1976 2 1976 N/A 12/10/1976 1.8 1977 53.9 04/02/1978 1978 86.3 08/12/1978 1.6 1979 96.9 27/12/1979 1.4 1980 109.2 02/11/1980 1981 81.1 14/07/1982 1.2 06/02/1990 1982 133.1 08/11/1982 30/12/1998 1 1983 160.1 16/12/1983 10/03/1995 1984 86.3 14/08/1985 0.8 21/10/1988 1985 148.3 06/08/1986 1986 130.6 08/12/1986 0.6

1987 131.8 01/02/1988 Flow(standardised by Qmed) 0.4 1988 162.8 21/10/1988 1989 194.9 06/02/1990 0.2 1990 93.7 28/12/1990 0 1991 94.8 25/11/1991 0 1 2 3 1992 83.2 13/01/1993 Time (days) 1993 123.3 15/01/1994 1994 164.1 10/03/1995 1995 117.4 07/01/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 144.4 05/08/1997 1997 118.5 04/01/1998 250 1998 165.5 30/12/1998 1999 109.2 25/12/1999 2000 156.1 06/11/2000 2001 112.7 23/01/2002 200 2002 96.9 27/11/2002 2003 92.1 14/11/2003 2004 130.0 29/10/2004 150 2005 108.1 22/05/2006 2006 105.8 03/12/2006 2007 140.6 10/01/2008 100 2008 134.8 31/01/2009 AMAX Flow (cumecs) 2009 122.3 19/11/2009

50 Length of AMAX series : 33 years 2 5 10 25 50 100 200 Return Period 0 -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 7 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24009 – MAIGUE AT ADARE MANOR

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Level Date Easting: 147355 Northing: 146220 Year (mOD) 1946 Catchment: Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 839.40 km 2 1949 1950 1951 QMED (gauged): N/A m 3/s AREA (FSU): N/A km 2 1952 1953 QMED (FSU): N/A m 3/s SAAR (FSU): N/A 1954 1955 QMED (predicted): N/A m3/s FARL (FSU): N/A 1956 1957 BFIsoils (FSU): N/A S1085: N/A 1958 1959 URBEXT: N/A ARTDRAIN2: N/A 1960 1961 DRAIND: N/A 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : No OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 7.4 01/12/1973 1974 6.8 15/01/1975 Chart not available 1975 6.9 30/01/1976 1976 N/A N/A 1977 6.3 11/01/1978 1978 6.3 01/02/1979 1979 6.5 21/01/1980 1980 6.5 22/10/1980 1981 6.8 14/12/1981 1982 6.7 03/02/1983 1983 7.1 16/12/1983 1984 6.7 23/11/1984 1985 6.9 06/08/1986 1986 6.7 01/01/1987 1987 6.8 19/01/1988 1988 7.1 11/10/1988 1989 7.5 06/02/1990 1990 6.9 05/01/1991 1991 6.8 25/11/1991 1992 6.8 22/10/1992 1993 6.7 27/02/1994 1994 6.9 10/03/1995 1995 6.9 07/01/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 6.7 28/10/1996 1997 7.0 18/10/1997 8 1998 7.2 30/12/1998 1999 7.1 25/12/1999 2000 6.6 06/11/2000 2001 7.0 01/02/2002 2002 6.6 01/12/2002 2003 6.2 11/03/2004 7 2004 6.9 08/01/2005 2005 6.5 30/03/2006 2006 7.0 20/02/2006 2007 6.8 10/01/2008 Level (mAOD)

2008 6.6 31/01/2009 6 2009 6.8 30/03/2010

Length of AMAX series : 36 years 2 5 10 25 50 100 200

Return Period 2005 - record not complete due to 5 recorder malfunction. -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 8 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24011 – DEEL AT DEEL BR.

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Flow Date Easting: 129938 Northing: 132738 Year (m 3/s) 1946 Catchment: Maigue Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 281.20 km 2 1949 1950 1951 QMED (gauged): 88.74 m 3/s AREA (FSU): 281.23 km 2 1952 1953 QMED (FSU): 100.88 m 3/s SAAR (FSU): 1058.19 1954 1955 QMED (predicted): 58.36 m3/s FARL (FSU): 1.00 1956 1957 BFIsoils (FSU): 0.49 S1085: 2.31 1958 1959 URBEXT: 1.22 ARTDRAIN2: 42.00 1960 1961 DRAIND: 1.09 1962 1963 Comments: Automated velocity- area station installed in 1940. Natural channel with a 1964 bridge which acts as flow control. Unstable gravel bed. Drainage 62-68. 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : YES OPW Station Classification: B 1971 1972 104.9 23/05/1973 Normalised Hydrographs 1973 171.7 01/12/1973 1974 88.3 20/01/1975 1975 96.5 29/01/1976 2 1976 55.5 17/03/1977 1.8 1977 96.5 20/04/1978 1978 103.6 07/12/1978 1.6 1979 96.3 24/10/1979 1.4 1980 124.7 02/11/1980 1981 71.4 13/12/1981 1.2 25/01/1995 1982 114.2 31/01/1983 01/08/2008 1 1983 109.1 16/12/1983 15/01/1994 1984 67.1 14/08/1985 0.8 06/02/1990 1985 127.6 06/08/1986 1986 81.1 08/12/1986 0.6

1987 103.6 01/02/1988 Flow(standardised by Qmed) 0.4 1988 126.6 11/10/1988 1989 108.2 06/02/1990 0.2 1990 82.8 28/12/1990 0 1991 89.8 21/12/1991 0 1 2 3 1992 61.2 13/01/1993 Time (days) 1993 114.9 15/01/1994 1994 130.5 25/01/1995 1995 103.6 09/02/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 78.4 04/08/1997 1997 70.3 04/01/1998 200 1998 89.2 29/12/1998 1999 75.4 24/12/1999 180 2000 79.4 26/11/2000 2001 75.4 23/01/2002 160

2002 64.6 21/10/2002 140 2003 81.0 14/11/2003 2004 85.6 08/01/2005 120 2005 76.1 21/05/2006 100 2006 63.1 03/12/2006 2007 115.4 01/08/2008 80 2008 77.7 04/12/2008 AMAX Flow (cumecs) 2009 77.7 19/11/2009 60

40 Length of AMAX series : 38 years 2 5 10 25 50 100 200 20 Return Period

0 -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 9 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24012 – DEEL AT GRANGE BR.

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Flow Date Easting: 130810 Northing: 135013 Year (m 3/s) 1946 Catchment: Maigue Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 366.30 km 2 1949 1950 1951 QMED (gauged): 112.82 m 3/s AREA (FSU): 366.28 km 2 1952 1953 QMED (FSU): 130.03 m 3/s SAAR (FSU): 1073.02 1954 1955 QMED (predicted): 80.58 m3/s FARL (FSU): 1.00 1956 1957 BFIsoils (FSU): 0.47 S1085: 2.25 1958 1959 URBEXT: 1.59 ARTDRAIN2: 36.00 1960 1961 DRAIND: 1.23 1962 1963 Comments: Automated velocity- area station installed in 1954. Open channel with 1964 100.8 12/12/1964 natural control. Extensive out of bank flow at high levels. 1965 112.8 09/12/1965 1966 104.9 22/02/1967 1967 103.5 07/10/1967 Nearby APSRs : To be confirmed 1968 139.4 02/11/1968 1969 89.6 21/02/1970 1970 88.8 18/11/1970 Jacobs Rating Review required : YES OPW Station Classification: B 1971 95.4 02/02/1972 1972 94.0 23/05/1973 Normalised Hydrographs 1973 141.9 01/12/1973 1974 102.4 22/01/1975 1975 107.7 29/01/1976 2 1976 72.5 17/03/1977 1.8 1977 109.1 20/04/1978 1978 112.8 07/12/1978 1.6 1979 107.2 25/10/1979 1.4 1980 135.8 02/11/1980 1981 85.8 13/12/1981 1.2 31/07/2008 1982 125.8 31/01/1983 01/12/1973 1 1983 115.2 16/12/1983 11/10/1988 1984 87.1 14/08/1985 0.8 02/11/1968 1985 133.8 06/08/1986 1986 99.9 18/11/1986 0.6

1987 118.1 01/02/1988 Flow(standardised by Qmed) 0.4 1988 140.2 11/10/1988 1989 120.2 06/02/1990 0.2 1990 101.2 28/12/1990 0 1991 100.8 21/12/1991 0 1 2 3 1992 75.3 13/01/1993 Time (days) 1993 122.9 15/01/1994 1994 134.3 25/01/1995 1995 110.5 09/02/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 114.2 05/08/1997 1997 105.6 04/01/1998 180 1998 125.8 29/12/1998

1999 110.0 05/11/1999 160 2000 115.2 25/11/2000 2001 114.2 01/02/2002 140 2002 98.1 21/10/2002 2003 118.1 14/11/2003 120 2004 137.9 08/01/2005 2005 113.3 21/05/2006 100

2006 114.7 03/12/2006 80 2007 156.3 31/07/2008 AMAX AMAX Flow (cumecs) 2008 115.7 04/12/2008 60 2009 123.1 19/11/2009 40 Length of AMAX series : 46 years 20 Return Period 2 5 10 25 50 100 200 1975- clock stopped on recorder - peak 0 estimated -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 10 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24013 – DEEL AT RATHKEALE

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Flow Date Easting: 136009 Northing: 141444 Year (m 3/s) 1946 Catchment: Maigue Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 438.80 km 2 1949 1950 1951 QMED (gauged): 101.47 m 3/s AREA (FSU): 438.79 km 2 1952 1953 55.4 27/02/1954 QMED (FSU): 109.60 m 3/s SAAR (FSU): 1071.60 1954 46.5 01/12/1954 1955 47.8 12/12/1955 QMED (predicted): 92.38 m3/s FARL (FSU): 1.00 1956 61.3 01/01/1957 1957 31.0 24/05/1958 BFIsoils (FSU): 0.47 S1085: 1.94 1958 39.7 20/12/1958 1959 44.5 11/12/1959 URBEXT: 1.60 ARTDRAIN2: 39.00 1960 85.8 03/12/1960 1961 36.4 28/01/1962 DRAIND: 1.19 1962 32.1 02/11/1962 1963 N/A N/A Comments: Automated velocity-area station installed in 1940 and automated in 1953. 1964 N/A N/A Stable gravel bed and loose rock weir as low flow control. Natural channel control for 1965 N/A N/A higher flows. 1966 N/A N/A 1967 N/A N/A Nearby APSRs : To be confirmed 1968 N/A N/A 1969 98.1 17/02/1970 1970 106.1 19/11/1970 Jacobs Rating Review required : YES OPW Station Classi fication: A1 1971 109.6 02/02/1972 1972 90.3 23/05/1973 Normalised Hydrographs 1973 145.3 01/12/1973 1974 97.5 22/01/1975 1975 99.8 30/01/1976 2 1976 74.6 17/03/1977 1.8 1977 101.5 20/04/1978 1978 110.8 07/12/1978 1.6 1979 102.0 27/12/1979 1.4 1980 133.6 02/11/1980 1981 83.9 13/12/1981 1.2 01/12/1973 1982 110.2 31/01/1983 30/12/1998 1 1983 113.8 17/12/1983 02/11/1980 1984 80.7 19/08/1985 0.8 01/08/2008 1985 113.2 26/08/1986 1986 91.4 08/12/1986 0.6

1987 110.8 01/02/1988 Flow(standardised by Qmed) 0.4 1988 130.4 22/10/1988 1989 120.4 06/02/1990 0.2 1990 101.5 29/12/1990 0 1991 97.5 21/12/1991 0 1 2 3 1992 79.2 13/01/1993 Time (days) 1993 122.3 15/01/1994 1994 130.1 26/01/1995 1995 119.8 10/02/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 116.8 05/08/1997 1997 109.3 05/01/1998 160 1998 137.4 30/12/1998 1999 118.6 25/12/1999 140 2000 122.9 06/11/2000 2001 106.7 24/01/2002 120 2002 92.5 02/12/2002 2003 109.6 14/11/2003 100 2004 110.2 08/01/2005 2005 92.0 23/05/2006 80 2006 86.5 04/12/2006 2007 133.6 01/08/2008

AMAX AMAX Flow (cumecs) 60 2008 99.8 04/12/2008 2009 117.8 19/11/2009 40

Length of AMAX series : 51 years 20 2 5 10 25 50 100 200 Return Period 1987 - water level estimated 0 -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 11 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24015 – AHAVARRAGH AT DROMCOLLIHER

Annual Maxima Series (Source: ) Gauging Authority: Limerick County Council

Hydrological Flow Date Easting: 137926 Northing: 121362 Year (m 3/s) 1946 Catchment: Telemetry: No 1947 1948 Station Type: Recorder Catchment Area: 5.20 km 2 1949 1950 1951 QMED (gauged): N/A m 3/s AREA (FSU): N/A km 2 1952 1953 QMED (FSU): N/A m 3/s SAAR (FSU): N/A 1954 1955 QMED (predicted): N/A m3/s FARL (FSU): N/A 1956 1957 BFIsoils (FSU): N/A S1085: N/A 1958 1959 URBEXT: N/A ARTDRAIN2: N/A 1960 1961 DRAIND: N/A 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : YES OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 1974 Chart not available 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 Flood Frequency (EV1 with Gringorten plotting positions) 1996 1997 Chart not available 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Length of AM AX series : years

Last Updated: May 2011 Last saved by Jacobs Page 12 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24022 – MAHORE AT HOSPITAL

Annual Maxima Series (Source: FSU) Gauging Authority: Limerick County Council

Hydrological Flow Date Easting: 170565 Northing : 136283 Year (m 3/s) 1946 Catchment: Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 41.20 km 2 1949 1950 1951 QMED (gauged): 9.80 m 3/s AREA (FSU): 41.21 km 2 1952 1953 QMED (FSU): 9.80 m 3/s SAAR (FSU): 942.31 1954 1955 QMED (predicted): 7.56 m3/s FARL (FSU): 1.00 1956 1957 BFIsoils (FSU): 0.62 S1085: 3.29 1958 1959 URBEXT: 0.33 ARTDRAIN2: 70.00 1960 1961 DRAIND: 1.05 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : No OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 1974 Chart not available 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 5.0 22/01/1986 1986 9.3 08/12/1986 1987 7.6 12/01/1988 1988 10.0 11/10/1988 1989 11.5 06/02/1990 1990 3.8 28/12/1990 1991 5.6 24/11/1991 1992 5.0 13/01/1993 1993 6.2 15/01/1994 1994 15.0 22/02/1995 1995 10.0 24/11/1995 Flood Frequency (EV1 with Gringorten plotting positions) 1996 6.7 29/11/1996 1997 9.4 17/10/1997 25 1998 13.6 29/12/1998 1999 10.0 18/12/1999 2000 20.5 06/11/2000 2001 14.2 26/02/2002 20 2002 9.6 27/11/2002 2003 11.3 14/11/2003 2004 12.3 28/10/2004 15 2005 2006 2007 10 2008 AMAX Flow (cumecs) 2009

5 Length of AMAX series : 20 years 2 5 10 25 50 100 200 Return Period 0 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 13 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24029 – DEEL AT INCHIROURKE MORE

Annual Maxima Series (Source: ) Gauging Author ity: Limerick County Council

Hydrological Flow Date Easting: 134386 Northing: 149141 Year (m 3/s) 1946 Catchment: Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 486.10 km 2 1949 1950 1951 QM ED (gauged): N/A m 3/s AREA (FSU): N/A km 2 1952 1953 QMED (FSU): N/A m 3/s SAAR (FSU): N/A 1954 1955 QMED (predicted): N/A m3/s FARL (FSU): N/A 1956 1957 BFIsoils (FSU): N/A S1085: N/A 1958 1959 URBEXT: N/A ARTDRAIN2: N/A 1960 1961 DRAIND: N/A 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : YES OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 1974 Chart not available 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 Flood Frequency (EV1 with Gringorten plotting positions) 1996 1997 Chart not available 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Length of AMAX series : years

Last Updated: May 2011 Last saved by Jacobs Page 14 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24030 – DEEL AT DANGANBEG

Annual Maxima Series (Source: FSU) Gauging Authority: Limerick County Council

Hydrological Flow Date Easting: 131830 Northing: 129038 Year (m 3/s) 1946 Catchment: Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 258.90 km 2 1949 1950 1951 QMED (gauged): 52.00 m 3/s AREA (FSU): 258.88 km 2 1952 1953 QMED (FSU): 52.00 m 3/s SAAR (FSU): 1051.24 1954 1955 QMED (predicted): 59.52 m3/s FARL (FSU): 1.00 1956 1957 BFIsoils (FSU): 0.44 S1085: 2.40 1958 1959 URBEXT: 1.07 ARTDRAIN2: 40.00 1960 1961 DRAIND: 1.10 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : YES OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 1974 Chart not available 1975 1976 1977 1978 1979 1980 69.5 02/11/1980 1981 39.1 13/12/1981 1982 60.6 08/11/1982 1983 67.7 16/12/1983 1984 44.0 14/08/1985 1985 72.2 06/08/1986 1986 53.0 08/12/1986 1987 50.9 01/02/1988 1988 55.8 21/10/1988 1989 51.8 06/02/1990 1990 43.7 28/12/1990 1991 47.9 21/12/1991 1992 37.8 13/01/1993 1993 53.5 16/01/1994 1994 52.8 10/03/1995 1995 50.1 09/02/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 53.3 05/08/1997 1997 50.2 08/01/1998 80 1998 54.9 29/12/1998 1999 51.8 05/11/1999 70 2000 54.6 26/11/2000 2001 53.1 23/01/2002 60 2002 50.7 21/10/2002 2003 51.3 14/11/2003 50 2004 52.0 08/01/2005 2005 40 2006 2007

AMAX AMAX Flow (cumecs) 30 2008 2009 20

Length of AMAX series : 25 years 10 2 5 10 25 50 100 200 Return Period 0 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 15 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24034 – LOOBAGH AT RIVERSFIELD WEIR

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Flow Date Easting: 163231 Northing: 126306 Year (m 3/s) 1946 Catchment: Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 54.60 km 2 1949 1950 1951 QMED (gauged): 24.70 m 3/s AREA (FSU): N/A km 2 1952 1953 QMED (F SU): N/A m 3/s SAAR (FSU): N/A 1954 1955 QMED (predicted): N/A m3/s FARL (FSU): N/A 1956 1957 BFIsoils (FSU): N/A S1085: N/A 1958 1959 URBEXT: N/A ARTDRAIN2: N/A 1960 1961 DRAIND: N/A 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : YES OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 1974 1975 2 1976 1.8 1977 1978 1.6 1979 1.4 1980 1981 1.2 27/10/2004 1982 09/01/2008 1 1983 02/12/2005 1984 0.8 30/01/2009 1985 18.8 06/08/1986 1986 10.6 11/12/1986 0.6

1987 18.8 19/01/1988 Flow(standardised by Qmed) 0.4 1988 33.2 11/10/1988 1989 32.0 06/02/1990 0.2 1990 15.1 28/12/1990 0 1991 24.7 25/11/1991 0 1 2 3 1992 14.6 30/09/1993 Time (days) 1993 29.8 19/02/1994 1994 35.1 22/02/1995 1995 28.1 24/11/1995 Flood Frequency (EV1 with Gringorten plotting positions) 1996 34.8 05/08/1997 1997 26.6 17/11/1997 40 1998 29.5 29/12/1998 1999 19.7 05/11/1999 35 2000 30.7 30/11/2000 2001 20.0 23/01/2002 30 2002 29.5 27/11/2002 2003 17.3 14/11/2003 25 2004 31.0 27/10/2004 2005 22.3 02/12/2005 20 2006 13.8 03/12/2006 2007 27.2 09/01/2008

AMAX AMAX Flow (cumecs) 15 2008 20.2 30/01/2009 2009 14.0 01/11/2009 10 Return Period 2 5 10 25 50 100 200 Length of AMAX series : 25 years 5

0 -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 16 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24067 – GREANAGH AT NORMOYLE'S BR.

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Level Date Easting: 144057 Northing: 145659 Year (mOD) 1946 Catchment: Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 83.60 km 2 1949 1950 1951 QMED (gauged): N/A m 3/s AREA (FSU): N/A km 2 1952 1953 QMED (FSU): N/A m 3/s SAAR (FSU): N/A 1954 1955 QMED (predicted): N/A m3/s FARL (FSU): N/A 1956 1957 BFIsoils (FSU): N/A S1085: N/A 1958 1959 URBEXT: N/A ARTDRAIN2: N/A 1960 1961 DRAIND: N/A 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : No OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 1974 Chart not available 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 6.5 15/01/1994 1994 7.0 26/01/1995 1995 6.5 09/02/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 7.0 05/08/1997 1997 6.6 17/10/1997 Chart not available 1998 6.7 30/12/1998 1999 6.6 24/12/1999 2000 6.7 06/11/2000 2001 6.6 01/02/2002 2002 5.2 19/02/2003 2003 5.2 19/03/2004 2004 6.7 28/10/2004 2005 6.4 30/03/2006 2006 6.5 07/12/2006 2007 6.6 10/03/2008 2008 6.3 13/12/2008 2009 6.6 14/11/2009

Length of AMAX series : 17 years

Last Updated: May 2011 Last saved by Jacobs Page 17 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24082 – MAIGUE AT ISLANDMORE

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Flow Date Easting: 151496 Northing: 139971 Year (m 3/s) 1946 Catchment: Maigue Tele metry: Yes 1947 1948 Station Type: Recorder Catchment Area: 762.80 km 2 1949 1950 1951 QMED (gauged): 140.01 m 3/s AREA (FSU): 762.84 km 2 1952 1953 QMED (FSU): 140.01 m 3/s SAAR (FSU): 941.70 1954 1955 QMED (predicted): 117.61 m3/s FARL (FSU): 1.00 1956 1957 BFIsoils (FSU): 0.53 S1085: 1.91 1958 1959 URBEXT: 0.64 ARTDRAIN2: 51.00 1960 1961 DRAIND: 1.10 1962 1963 Comments: Automated velocity-area station installed and automated in 1977. Stable 1964 mud bed. Non-standard weir, with some bridge effect at the very high flows. 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : No OPW Station Classification: A2 1971 1972 Normalised Hydrographs 1973 1974 1975 2 1976 1.8 1977 57.5 20/11/1977 1978 103.6 08/12/1978 1.6 1979 92.6 25/10/1979 1.4 1980 103.6 02/11/1980 1981 80.6 14/07/1982 1.2 06/02/1990 1982 140.0 08/11/1982 06/11/2000 1 1983 170.8 16/12/1983 21/10/1988 1984 77.7 14/08/1985 0.8 22/02/1995 1985 155.1 06/08/1986 1986 140.0 08/12/1986 0.6

1987 143.7 01/02/1988 Flow(standardised by Qmed) 0.4 1988 183.0 21/10/1988 1989 206.4 06/02/1990 0.2 1990 125.6 28/12/1990 0 1991 125.6 25/11/1991 0 1 2 3 1992 110.2 30/09/1993 Time (days) 1993 147.5 15/01/1994 1994 178.9 22/02/1995 1995 129.1 10/02/1996 Flood Frequency (EV1 with Gringorten plotting positions) 1996 157.0 05/08/1997 1997 141.9 05/01/1998 250 1998 178.9 30/12/1998 1999 130.9 25/12/1999 2000 185.1 06/11/2000 2001 141.9 23/01/2002 200 2002 118.7 27/11/2002 2003 110.2 14/11/2003 2004 157.0 29/10/2004 150 2005 130.9 23/05/2006 2006 116.9 03/12/2006 2007 149.4 10/01/2008 100 2008 146.5 31/01/2009 AMAX Flow (cumecs) 2009 128.8 19/11/2009

50 Length of AMAX series : 33 years 2 5 10 25 50 100 200 Return Period 0 -3 -2 -1 0 1 2 3 4 5 6 Reduced variate

Last Updated: May 2011 Last saved by Jacobs Page 18 of 20

Shannon Catchment Flood Risk Assessment and Management (CFRAM) Study Gauging Station Information Sheet

24100 – DEEL AT GORTBOY HOTEL

Annual Maxima Series (Source: OPW) Gauging Authority: Office of Public Works

Hydrological Flow Date Easting: 128600 Northing: 133493 Year (m 3/s) 1946 Catchment: Telemetry: Yes 1947 1948 Station Type: Recorder Catchment Area: 0.00 km 2 1949 1950 1951 QMED (gauged): 34.89 m 3/s AREA (FSU): N/A km 2 1952 1953 QMED (FSU): N/A m 3/s SAAR (FSU): N/A 1954 1955 QMED (predicted): N/A m3/s FARL (FSU): N/A 1956 1957 BFIsoils (FSU): N/A S1085: N/A 1958 1959 URBEXT: N/A ARTDRAIN2: N/A 1960 1961 DRAIND: N/A 1962 1963 Comments: 1964 1965 1966 1967 Nearby APSRs : To be confirmed 1968 1969 1970 Jacobs Rating Review required : No OPW Station Classification: None 1971 1972 Normalised Hydrographs 1973 1974 Chart not available 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 Flood Frequency (EV1 with Gringorten plotting positions) 1996 1997 Chart not available 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 64.7 01/08/2008 2008 28.2 02/09/2009 2009 34.9 19/11/2009

Length of AMAX series : 3 years

2007 - flood mark surveyed (gauge installed 21/11/2008)

Last Updated: May 2011 Last saved by Jacobs Page 19 of 20

Last Updated: May 2011 Last saved by Jacobs Page 20 of 20