Camac Model DOCUMENT CONTROL SHEET

Eastern CFRAM Study

HA09 Hydraulics Report

Client OPW

Project Title Eastern CFRAM Study

Document Title IBE0600Rp0027_HA09_Hydraulics Report_Camac_F01

Document No. IBE0600Rp0027_ Camac

DCS TOC Text List of Tables List of Figures No. of This Document Appendices Comprises 1 1 55 0 0 3

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

D03 Draft A. Sloan A. Jackson G. Glasgow Belfast 21/03/2014

D04 Draft A. Sloan A. Jackson G. Glasgow Belfast 30/09/2014

D05 Draft A. Sloan A. Jackson G. Glasgow Belfast 30/10/2014

D06 Draft A. Sloan A. Jackson G. Glasgow Belfast 29/01/2015

F01 Draft Final A. Sloan A. Jackson G. Glasgow Belfast 16/09/2016

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Legal Disclaimer

This report is subject to the limitations and warranties contained in the contract between the commissioning party (Office of Public Works) and RPS Group Ireland

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Eastern CFRAM Study HA09 Hydraulics Report – DRAFT FINAL

TABLE OF CONTENTS

4 HYDRAULIC MODEL DETAILS ...... 4 4.5 CAMAC MODEL ...... 4 4.5.1 General Hydraulic Model Information ...... 4 4.5.2 Hydraulic Model Schematisation ...... 6 4.5.3 Hydraulic Model Construction ...... 13 4.5.4 Hydraulic Model Calibration and Verification ...... 23 4.5.5 Sensitivity Analysis ...... 34 4.5.6 Hydraulic Model Assumptions, Limitations and Handover Notes ...... 43

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4 HYDRAULIC MODEL DETAILS

4.5 CAMAC MODEL

4.5.1 General Hydraulic Model Information

(1) Introduction

The Eastern CFRAM Flood Risk Review (IBE0600Rp0001_Flood Risk Review) highlighted the Camac catchment as an Area for Further Assessment and a High Priority Watercourse based on a review of historic flooding and the extents of flood risk determined during the PFRA. The Camac system is a significant tributary of the River Liffey which emanates in the foothills of the Wicklow Mountains to the south of Dublin City. The catchment area is 58 km2 and is highly urbanised in the lower reaches (50% of the total catchment). The catchment is also characterised by many sub-catchments or branches many of which represent urban drainage networks.

There have been two gauging stations located in the catchment within close proximity to one another in the middle reaches of the main river channel. One was located at Clondalkin (09005 - EPA) which was active from 1976 to 1984. The other is located at Killeen Road (09035 - EPA) and has been active since 1996, more detail on the use of these stations and the hydrology derived from them can be found in Section 4.5 of the HA09 Hydrology Report (IBE0600Rp0016_HA09_Hydrology Report).

Historically flooding within the Camac catchment originates mainly from fluvial sources in the upstream portion of the catchment, with the Camac River and its tributaries overflowing its banks at a number of locations during recent times. More specific details of historic flooding in the Camac catchment can be found in Section 4.3.2 of the HA09 Inception Report (IBE0600Rp0008_HA09_Inception Report). Some historic flooding in the mid catchment reaches in the vicinity of the M50 crossing and Nangor road has been attributed to bridge and culvert blockages, with businesses constructing localised defences to reduce flood risk to their properties.

Residents in the downstream reaches of the catchment have also reported the under capacity of the drainage network as causing flooding during storm events. The model constructed for the Camac catchment is comprised of 1D channel reaches with associated structures, specific topographical channel and structure survey data was captured for the model construction. The Camac floodplain is entirely represented using a Triangular Flexible 2D mesh defined by LiDAR data with building represented using impermeable porous polygons. The 2D mesh is connected to the 1D channel via bank units, once the bank unit levels are exceeded the water then spills to the 2D mesh floodplain. Residents in the downstream reaches of the catchment have also reported the under capacity of the drainage network as causing flooding during storm events however this model does not include drainage infrastructure. As such only fluvial/coastal flooding originating from the main river channel and tributaries has been investigated as per the CFRAM Studies specification.

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(2) Model Reference: HA09_CAMM

(3) AFAs included in the model: Dublin

(4) Primary Watercourses / Water Bodies (including local names):

CAMAC RATHCOOLE SAGGART

VERSCHOYLES COOLMINE KILNAMANAGH

CITYWEST LINK CRUMLIN

FITZMAURICE ALVERNA KINGSWOOD

WALKINSTOWN CORKAGH CHEEVERSTOWN

BROOKVIEW FORTUNESTOWN TALLAGHT

(5) Software Type (and version): InfoWorks ICM v5

(a) 1D Domain: Infoworks ICM (b) 2D Domain: Infoworks ICM - (c) Other model elements:

Flexible Mesh n/a

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4.5.2 Hydraulic Model Schematisation

(1) Map of Model Extents:

Map of Model Extents (Upper Catchment)

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Map of Model Extents (Middle Catchment)

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Map of Model Extents (Lower Catchment)

The Maps of Model Extents above illustrate the extent of the modelled catchment, river centre line, HEP locations and AFA extents as applicable. The Camac catchment has been designated as a high priority

IBE0600Rp00027 8 F01 Eastern CFRAM Study HA09 Hydraulics Report – DRAFT FINAL watercourse (HPW) in the Dublin AFA and as such does not have a Distinct AFA Extent. The Camac catchment is bounded by the Griffeen, Poddle and Dodder catchments. The computational modelling predicts that some flood flow will spread to the Griffeen catchment during the 0.1% AEP event. Some of the Camac's natural catchment has also been diverted to the Dodder River at Tallaght. Some minor inflow to the Camac River from the Grand Canal occurs at Lansdowne Valley Park via an overflow weir and fountain.

A number of types of hydrological estimation points (HEPs) have been employed throughout the Eastern CFRAM Study, these are described in more detail below.

HEP at Upstream Limit of Model

The upstream extent of each model requires a HEP at which design flows and hydrographs will be derived primarily from a rainfall runoff model; or flow estimation methods as appropriate (for example in small catchments). Upstream model limits will always be at 1km2 contributing catchment areas or more.

HEP where tributaries enter modelled channel

Moving downstream along the modelled reach, a HEP is located where tributaries with catchment areas greater than 5km2 enter the channel. The Generic CFRAM Study Brief required these HEPs at tributaries where it was considered that more than 10% of the main channel flow was contributed. However, this application led to an abundance of HEPs at tributary confluences in the upper reaches of catchments, and under representation in the lower reaches. This was discussed with the OPW and it was considered that including all tributaries with catchments greater than 5km2 would ensure a more appropriate distribution of HEPs at tributary confluences throughout the catchment. On High Priority Watercourses it will often be appropriate to include flows from catchments which are much smaller than 5km² and where this is the case the inclusion of tributaries will be considered on an individual basis.

HEP at gauging stations on modelled channel

At gauging stations along the modelled reaches (for which data is available), a HEP is located. These HEPs serve as check points throughout the modelled catchment, so that flow estimates can be calibrated on a catchment basis ensuring appropriate discharges are modelled for each design event.

Intermediate/Reporting HEPs

Intermediate/Reporting HEPs have both hydraulic input (top-up) and reporting functions as described below:

 Hydrology estimations at HEPs will be undertaken to ensure that the total contributing catchment at that point in the model can be checked to ensure that the sum of the model inputs are consistent with the total catchment up to that point in the model. The estimated flows at HEPs will also be used to check against modelled flows at the same location. Where necessary the models may need to be ‘topped up’ by increasing the lateral inflows upstream of these HEPs to ensure all of the contributing catchment is considered

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 HEPs along main channel with maximum distance of 5km – this is a requirement of the Generic CFRAM Study Brief. HEPs will serve as reporting points where calibrated peak flows for each design event at the end of the hydraulic analysis task and will be reported as a CFRAM Study deliverable.

 HEPs immediately upstream and downstream of AFAs and in the centre of each AFA - this is a requirement of the Generic CFRAM Study Brief. At these HEPs calibrated peak flows for each design event will be reported at the end of the hydraulic analysis task as a CFRAM Study deliverable.

HEP at Downstream Limit of the Model

The downstream extent of each model requires a HEP such that the total contributing catchment can be estimated in order to check that the sum of the model inputs are consistent with hydrology estimations for the whole catchment. These will act as upstream limit HEPs where a further model is connected downstream. Where a gauging station HEP forms the boundary between two models this will act as the upstream and downstream HEP for the respective models.

Summary of HEPs in the Camac catchment

The Camac catchment contains a number HEPs as summarised below;

15 Upstream Limit HEPs

17 Tributary HEPs

2 Gauging Station HEPs

6 Intermediate HEPs

1 Downstream Limit HEP

(2) x-y Coordinates of River (Upstream extent):

River Name x y River Name x y Camac 303195 222801 Link 302722 226676 Vershoyles 304947 225262 Alverna 303641 227058 City West 304649 227400 Saggart 304389 226448 Fitzmaurice 302565 226062 Kilnamanagh 309727 229567 Rathcoole 302240 225519 Crumlin 311479 231820 Coolmine 302719 225719 Kingswood 307855 230100 Walkinstown 310545 231116 Corkagh 305409 230069 Cheeverstown 306507 228371 Tallaght 306140 228007 Brookview 306380 227781 Fortunestown 305646 226296 (3) Total Modelled Watercourse Length: 42 kilometres (approx.)

(4) 1D Domain only Watercourse 0 km (5) 1D-2D Domain Watercourse 42 km Length: Length: (approx.)

(6) 2D Domain Mesh Type / Resolution / Area: Flexible Triangular / 1-25m2 / 38 km2

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(7) 2D Domain Model Extent and Catchment Topography:

The figure above illustrates the modelled extents of the Camac catchment and the general topography of the catchment. (8) Survey Information (a) Survey Folder Structure: First Level Folder Second Level Folder Third Level Folder e.g. GIS and Floodplain Flood_Defence_Register

Murphy_E09_M02D_WP6_120803_09CAMA Photos Structure_Register

Where: Surveyed_Cross-Section_Lines Ascii Murphy - Surveyor Name Photos (Naming E09 - Eastern CFRAM Study Area, convention is in the Hydrometric Area 09 format of Cross- M02D - Model Number 02D Section ID and WP6 - Work Package 6 orientation - 120803 - Date issued (03 August 2012) upstream, downstream, left bank 09CAM - River Reference or right bank) A- River sub-reach XS Drawings & PDFs (8)b Survey Folder References: Camac Murphy_E09_M02D_WP6_120803_09CAMA Murphy_E09_M02D_WP6_120803_09CAMM_A Murphy_E09_M02D_WP6_120803_09CAMM_B Murphy_E09_M02D_WP6_120803_09CAMM_C Murphy_E09_M02D_WP6_120803_09CAMM_D

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Rathcoole Murphy_E09_M02D_WP6_120803_09RATH Coolmine Murphy_E09_M02D_WP6_120803_09MINE Walkinstown Murphy_E09_M02D_WP6_120803_09WALK Cheeverstown Murphy_E09_M02D_WP6_120803_09CHEE Brookview Murphy_E09_M02D_WP6_120803_09VIEW Link Murphy_E09_M02D_WP6_120803_09LINK Alverna Murphy_E09_M02D_WP6_120803_09ALVE Saggart Murphy_E09_M02D_WP6_120803_09SAGN Murphy_E09_M02D_WP6_120803_09SAGA Crumlin Murphy_E09_M02D_WP6_120803_09CRUM Kingswood Murphy_E09_M02D_WP6_120803_09KING Corkagh Murphy_E09_M02D_WP6_120803_09CDEM Murphy_E09_M02D_WP6_120803_09CORA Murphy_E09_M02D_WP6_120803_09CORB Murphy_E09_M02D_WP6_120803_09CORD Murphy_E09_M02D_WP6_120803_09CORE_A Murphy_E09_M02D_WP6_120803_09CORE_B Murphy_E09_M02D_WP6_120803_09CORF Murphy_E09_M02D_WP6_120803_09CORG Murphy_E09_M02D_WP6_120803_09CORK

Tallaght Murphy_E09_M02D_WP6_120803_09TALLA Fortunestown Murphy_E09_M02D_WP6_120803_09FORT Vershoyles Murphy_E09_M02D_WP6_120803_09VERS City West Murphy_E09_M02D_WP6_120803_09WEST Fitzmaurice Murphy_E09_M02D_WP6_120803_09FITZ Kilnamanagh Murphy_E09_M02D_WP6_120803_09KILN

(9) Survey Issues: There were no survey queries in relation to the Liffey catchment (UoM09) survey data.

Infill surveys were carried out to record flood defence levels at the Diageo factory and Lady's Lane. The extent of these surveys is illustrated in the diagrams below.

Lady's Lane Flood Defence Infill Survey

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Diageo Flood Defence Infill Survey

4.5.3 Hydraulic Model Construction

(1) 1D Structures in the 1D domain: See Appendix A.1

Number of Bridges and Culverts: 143

Number of Weirs: 55

Structures present along the modelled reach of the Camac River, which significantly influence the in-channel hydraulics are presented below.

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Corkagh Park Sluice (09CAMM01202X) - A control structure at Corkagh Park, shown below, regulates the flow continuing down the main channel. A number of attenuation ponds are present at this location.

Bow Bridge 09CAMM00067 - This bridge significantly restricts flood flows, this flow constraint issue was also identified by residents and the local authority.

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Kearns Place Bridge 09CAMM00124 - This bridge was identified during modelling and consultation as causing a flow constriction during flood events.

Nangor Road Culvert 09CAMM00698 - Flooding was recorded upstream of these culverts in October 2011 with the model simulation also predicting flooding at this location.

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M5 Culvert 09CAMM00750- The modelling has predicted significant flooding upstream of the M50 culvert

Woodford Walk Bridge 09CAMM00789 - Flooding was reported in the vicinity of this bridge in October 2011

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(2) 1D Structures in the 2D domain: NA

(3) 2D Model structures: Corkagh Park Storage

(4) Defences

Type Watercourse Bank Model Start Chainage Model End (approx.) Chainage (approx.)

Corkagh Park Flood Camac NA Camm12230 Camm10600 Attenuation Scheme

DIAGEO Factory Flood Camac Left Camm6900 Camm6530 Defences

Robinhood Industrial Kilnamangh/ Left Kiln 5400 Walk 190 Estate Walkinstown/ Robinhood Stream

Lady's Lane River Wall Camac Right Camm 1430 Camm 1250

(5) Model Boundaries - Inflows:

Full details of the flow estimates are provided in the Hydrology Report (IBE0600Rp0016_HA09 Hydrology Report_F01 - Section 4.13 and Appendix D). The boundary conditions implemented in the model are shown below, hydrographs at each location have been applied as per the hydrology report referenced above.

Node ID Boundary Description Branch Name Boundary Co- Type ordinates

09_481_U Point Inflow US Boundary Camac 303270, 223197 09_435_U Point Inflow US Boundary Rathmine 302230, 225549 Fitz US Point Inflow US Boundary Fitzmaurice 302526, 226131 UN_Trib_Camac_10 Point Inflow Trib inflow Link 303124, 226843 UN_Trib_Camac_20 Point Inflow Trib inflow Camac 303117, 227176 09_464_1 Point Inflow US Boundary Vershoyles 304982, 225928 09_1308_U Point Inflow US Boundary Fortunestown 305431, 226507 SO06282001 Point Inflow Trib inflow Tallaght 306238, 228007 09_39_1 Point Inflow US Boundary Cheeverstown 306470, 228355 Camm00741_weir_ds Point Inflow Top Up Flow Camac 308247, 232002 09_1252_U Point Inflow US Boundary Kingswood 307873, 230103 UN_Trib_Camac_U Point Inflow US Boundary Kilnamanagh 309732, 229574 09_1243_U Point Inflow US Boundary Walkinstown 310535, 231117 09_832_U Point Inflow US Boundary Crumlin 311477, 231826 09Fitz0076_CUL_US Point Inflow Trib inflow Fitzmaurice 302720, 226673 Fitz00047D DS Point Inflow Trib inflow Fitzmaurice 302869, 226915 Fitz00041W DS Point Inflow Top Up Flow Fitzmaurice 302825, 226951 West US Point Inflow US Boundary City West 304817, 227477 Br01975D DS.2 Lateral Inflow Top Up Flow Camac 303355, 223612 Cu01752 DS.1 Lateral Inflow Top Up Flow Camac 303904, 225630

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Node ID Boundary Description Branch Name Boundary Co- Type ordinates

09RATH00150_CUL_DS.1 Lateral Inflow Top Up Flow Rathmine 302229, 225574 MINES_TRIB.1 Lateral Inflow Top Up Flow Rathmine 302836, 226309 Vers00296W DS.2 Lateral Inflow Top Up Flow Vershoyles 304981, 226161 Vers00086I DS.2 Lateral Inflow Top Up Flow Vershoyles 304517, 228025 Cu0161 DS.2 Lateral Inflow Top Up Flow Fortunestown 305423, 227894 09TALLA0099_BREAK.1 Lateral Inflow Top Up Flow Tallaght 305678, 228625 Br01509E DS.2 Lateral Inflow Top Up Flow Camac 303307, 227520 Cu01175I DS.1 Lateral Inflow Top Up Flow Camac 305116, 229802 Cu01070I DS.2 Lateral Inflow Top Up Flow Camac 305759, 230567 Cu00994I DS.1 Lateral Inflow Top Up Flow Camac 306354, 231013 cam00848 us.1 Lateral Inflow Top Up Flow Camac 307279, 231696 09KILN0054_CUL_DS.1 Lateral Inflow Top Up Flow Kilnamanagh 310267, 230840 09KILN_IN.1 Lateral Inflow Top Up Flow Kilnamanagh 310332, 231277 09KING00322_CUL_DS.1 Lateral Inflow Top Up Flow Kingswood 308423, 230317 09KING00243_WEIR_DS.1 Lateral Inflow Top Up Flow Kingswood 308888, 230556 09KING00136_CUL_DS.1 Lateral Inflow Top Up Flow Kingswood 309864, 230893 09KING00099_WEIR_DS.1 Lateral Inflow Top Up Flow Kingswood 310061, 231132 Crum00030W DS.1 Lateral Inflow Top Up Flow Crumlin 311430, 231861 Crum00019D DS.1 Lateral Inflow Top Up Flow Crumlin 311348, 231926 Camm00622_cul_us.1 Lateral Inflow Top Up Flow Camac 309372, 231972 CamMh54‐Xs513.1 Lateral Inflow Top Up Flow Camac 310327, 232317 Wr00376 DS.1 Lateral Inflow Top Up Flow Camac 311263, 232346 Br00244D DS.1 Lateral Inflow Top Up Flow Camac 311958, 233437 Br00105D DS.2 Lateral Inflow Top Up Flow Camac 313160, 233670

The figure above provides an example of an inflow hydrograph in the upper reaches of the Camac River and is applied as a lateral inflow along the reach Br01975D DS.2, the inflow is distributed along the entire reach.

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The figure above is an example of a modelled hydrograph extracted from the Camac model at the M7 underpass culvert near Rathcoole.

(6) Model Boundaries – The downstream boundary applied to the model is a stage boundary Downstream Conditions: extracted from the River Liffey computational model. A static stage boundary was applied to ensure the most onerous conditions were represented. For each event in the Camac catchment the level for the corresponding event in the Liffey catchment was applied as the downstream boundary. The coastal boundary condition used in the Liffey computational model for each of these events was the 50% AEP water level profile.

(7) Model Roughness:

(a) In-Bank (1D) Minimum 'n' value: 0.040 Maximum 'n' value: 0.150

Specific Areas of in Main Camac River upstream of Springbank Cottages (Rathcoole) - channel roughness The area depicted below was identified during a site visit as having significant stands of trees within the river channels. Large quantities of debris were also observed during the site visit. This reach was therefore attributed an unusually high Manning's n value of 0.150. Immediately upstream and downstream of this reach a roughness value of 0.060 was applied due to vegetation and debris in the channel.

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Downstream of the N7 to Clondalkin the Camac River has a relatively clean channel with some bends and bank foliage a Manning's n 0.040 was applied to this reach.

The following two images illustrate the Camac River from Clondalkin to the Nangor Road the river has relatively straight reaches with some gentle bends, its banks are generally lightly vegetated with some areas of engineered erosion control, a Manning's n value of 0.040 was maintained along these reaches, flow along these reaches begins to be dominated by bridges and culverts.

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The following three images depict the Camac River channel from Lansdowne Valley Park to its outfall culvert. The river banks along this reach have been heavily engineered and are predominantly made up of concrete walls which would normally attract a low Manning's n value. However there is some evidence of in-channel debris, overhanging foliage and in-channel obstructions such as manholes. The line of the river along this reach is not as straight as the previous reaches with numerous short bends. A Manning's value of 0.040 was therefore maintained along this reach.

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(b) MPW Out-of-Bank (1D) Minimum 'n' value: N/A Maximum 'n' value: N/A

(d) MPW/HPW Out-of-Bank Minimum 'n' value: 0.013 Maximum 'n' value: 0.060

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(2D) see figure below for detail.

Map of 2D Roughness (Manning's n)

The map above illustrates the roughness values applied within the 2D domain of the Camac computational model. Roughness in the 2D domain was applied based on land type areas defined in the Corine Land Cover Map with representative roughness values associated with each of the land cover classes in the dataset.

4.5.4 Hydraulic Model Calibration and Verification

(1) Key Historical Floods (from IBE0600Rp0008_HA09 Inception Report_F02 unless otherwise specified):

(a) 24-25/10/2011 Up to 90mm of rain was reported to have fallen within a 6 hour period on the evening 24 October 2011. This rainfall resulted in major flooding along the Camac watercourse and its tributaries. Post flood surveys were carried out to record flood extents and levels where possible. The resulting level information, photographs and anecdotal evidence of flood extent were used to calibrate the model. Rain gauges throughout Dublin City recorded rainfall totals total in excess of the 2% AEP and in some locations greater than the 1% AEP totals. The gauging station at Killeen Road on the Camac did not record any IBE0600Rp00027 23 F01 Eastern CFRAM Study HA09 Hydraulics Report – DRAFT FINAL

meaningful information. As such an assumption on calibration flows was made and the design 1% AEP values used. The table below presents a comparison of the recorded and modelled levels.

Observed Level Modelled Level Coordinate Description Level ID (m AOD) (m AOD)

8.766 in channel Camac 313071, Shannon Terrace 8.797 adjacent, 8.796 in 1 233655 2D domain

Faulkners Terrace Camac 313242, (Flooding was 8.255 8.21 2 233647 500mm deep)

8.471 in channel Camac 313141, Apartment Block (St. 8.206 adjacent, 8.155 in 3 233657 John's Well Way) 2D domain

Camac 312829, Lady's Lane 11.003 10.7 4 233624

Emmet Road (water was reported to be 11.69 in channel Camac 312663, 5'6" deep with 12.025 adjacent, 11.97 in 5 233604 flooding from river 2D domain and flow coming from the road)

Emmet Road (water Camac 312664, reported to be 3'6" 12.025 11.94 6 233598 deep at this location)

11.94 in channel Camac 312539, Kilmainham Orchard 12.069 adjacent, 12.27 in 7 233617 Apartment Block 2D domain

Apartment Block Camac Crescent Camac 312448, (unknown if level 11.734 12 8 233643 recorded is in basement car park)

Camac 312283, Apartment Block, 14.37 14.64 9 233636 Kilmainham Bank

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Camac 311922, The Tramyard 18.878 18.6 10 233359

19.27 in channel Camac 311895, V.M. Motors 19.2 adjacent, 19.4 in 11 233356 2D domain

Camac 311722, Flood Wrack 22.509 22.6 12 233156

Camac 310296, Flood Wrack 38.568 38.32 13 232376

Camac 310040, Road Flooded to Approxim 44.65 14 231585 150 - 200mm ately 44.6

Flooding directly 49.62 in channel Camac 310028, from river in 49.625 adjacent, 49.45 in 15 231103 Robinhood Industrial 2D domain Estate

Camac Robinhood 49.397 49.21 16

48.27 - 47.51 in Camac 308894, Diageo Factory 47.95 channel adjacent, 17 232021 48.08 in 2D domain

Woodford Walk (bridge blocked and cleared during the 2011 flooding Camac 307786, 50.78 ds affecting the 51.12 ds of bridge 18 232029 of bridge flooding in this location, blockage was not included in the model)

Camac 307267, Watery Lane 53.697 53.664 19 231700

Recorded flood mapping information is available for this event and was considered during the calibration. However the mapped extents are focused on local areas of flooding with no interconnection recorded between each flooded area. The figures below illustrate the areas of recorded flooding as denoted by red outlines and dots compared with the 1% AEP modelled extents.

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Shannon Terrace, Faulkners Terrace and Lady's Lane

Emmet Road, Kilmainham Orchard, Kilmainham Bank and The Tramyard

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Robinhood Industrial Estate, additional anecdotal evidence indicates that this area has flooded extensively on a number of occasions in the recent years.

Tyrconnell Road

In addition to the above mapped information of the flood event, Dublin City Council provided information on flooded areas, which is summarised below;

 A number of locations between Bow Bridge and Kearn's Place were reported as being flooded, these included - Bowbridge Dock and Bowbridge House Apartments, Apartment carparks in Mount Brown, 12 Houses along Faulkner's Terrace and 1 commercial property

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upstream of Faulkner's Terrace, carparks below St. John's Well Way Apartments and carparks at Old Cammock Bridge Apartments.

 A number of properties between Kearn's Place and South Circular Road were reported as being flooded, these included - 11 dwellings on Kearn's Place, 12 apartments upstream of Kearn's Place, the motor repair shop downstream of Millbrook Terrace, 32 dwellings on Millbrook Terrace, Lady's Lane and Carrickfoyle Terrace.

 Between South Circular Avenue and Turvey Avenue - 13 properties along Emmet Road and an apartment carpark in Turvey Avenue were reported to have flooded. The apartment carpark was estimated to have flooded to a depth in excess of 2m.

 Seven properties along Tyrconnell Street were reported to have flooded.

The model predicted representative flooding to all of the areas mentioned above.

There were no reports of flooding to properties below Bow Bridge; however the model predicts some minor, localised flooding to land surrounding a small number of properties downstream of Bow Bridge during the 1% AEP event. This flooding originates from the upstream side of the bridge and may have been sufficiently shallow to not inundate internal floor levels within the properties.

(b) 11/06/1993 The River Camac burst its banks at a number of locations causing flooding of private property in the Clondalkin area at Leinster Terrace, Old Nangor Road and Cherrywood Estate. The Baldonnel area was also affected by the River Camac overflowing with roads and houses flooded in Rathcoole and Saggart.

(c) 25/8/1986 Hurricane Charlie caused significant flooding throughout Dublin, with 100.8mm of rain falling in the Saggart area over 24hours. Along the River Camac, a total of 30 households were seriously affected by the flooding.

(d) 5th- Widespread flooding occurred across Dublin as a result of heavy rainfall. The 7th/11/1982 antecedent conditions compounded the situation with large amounts of rainfall during the previous weeks leaving surfaces already waterlogged.

Killeen Road Gauging Station

The Killeen Road Gauging Station is an EPA operated gauge primarily maintained to record low flow data for water quality purposes. A stage discharge comparison of spot gaugings and modelled data was undertaken to assess the performance of the model along this reach. The figure below provides a comparison between the recorded spot gaugings, the EPA rating Curve for the station and the modelled stage discharge values. The comparison indicates that the model can replicate the observed values and associated rating curve from low flows to approximately Qmed.

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Stage Discharge Comparison 45.4

45.3

45.2

45.1 Spot Gaugings Pre 2002 45 Spot Gaugings Post 2002 44.9 Stage (mAOD) Rating Curve 44.8 Modelled

44.7

44.6 0246810 Flow (m3/s)

Stage Discharge Relationship

View downstream towards gauging station

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View upstream towards gauging station

(2) HEP Flow Comparison

The table below presents a comparison between estimated flows calculated during the hydrological analysis and the peak flows from the computational model.

HEP ID River Modelled Peak Flow

m3/s

Model HEP Model HEP Percentage Model HEP 10% 10% 1% 1% Difference 0.1% 0.1% AEP AEP AEP AEP in 1% AEP AEP AEP Values

09_472_4 Camac 2.69 2.39 5.40 4.41 22.44 8.24 7.86 _RPS

09_472_8 Camac 3.32 3.49 6.41 6.41 0 11.61 11.85 _RPS

09_435_1 Rathcoole 1.108 1.11 2.06 2.05 0 3.56 3.66 _RPS

09_36_2 Rathcoole 1.36 1.36 2.61 2.52 3.6 4.15 4.49

09_586_3 Vershoyles 1.43 2.59 2.97 4.79 -38 5.63 8.55

09_618_5 Fortunestown 1.48 1.55 2.63 2.87 -8.4 2.93 5.11

09_360_4 Tallaght 2.37 2.71 4.40 5.00 -12 7.8 8.92 _RPS

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09_499_3 Camac 7.5 13.82 14.60 23.87 -38.8 18 41.2 _RPS

09005_RP Camac 14.0 18.89 22.99 33.35 -31 37.9 56.63 S

09035_RP Camac 15.14 20.83 23.00 36.10 -36 29.1 60.17 S

Un_Trib_C Kilnamanagh 2.1 2.02 4.02 3.74 7.5 6.7 6.66 amac1

09_1242_ Kingswood 5.6 5.45 10.10 10.08 0 18 17.97 2_RPS

09_1872_ Camac 32 32.72 50.70 55.65 -8.9 88.7 91.29 9_RPS 09_472_4_RPS: There is a 22% difference in the modelled and estimated flows at this HEP point for the 1% AEP event. This difference is a result of additional inflow from additional catchment upstream which is entered into the top of the model over and above the catchment area delineated under FSU. The FSU catchment commences at the outfall of the reservoir at Glenaraneen and assumes no flood flow is contributed to the Camac from the catchment upstream of the reservoir. During the hydrological analysis this was not considered prudent as the performance of the reservoir during flood conditions is unknown. As such the area upstream of the reservoir (approximately 2.9km2) has been added to Camac catchment. Just downstream of the reservoir (at the HEP in question) the physical catchment descriptors are highly uncertain given the addition of this portion of catchment. Further downstream (09_472_8_RPS) where this additional catchment area represents a much smaller proportion of the catchment the flows are in much better agreement. In this context the initial 22% increase in flow above catchment descriptor based estimates is considered acceptable.

09_586_3: The difference of -38% is due to significant flooding along this tributary with comparatively large areas of ponding. The downstream hydrograph at this check HEP is significantly wider than input hydrographs indicating attenuation of peak flows.

09_618_5: Some flooding and ponding has led to the slight reduction of -8.4% in peak flows at this HEP node.

09_360_4_RPS: Flooding and subsequent attenuation upstream of this HEP has led to the slight reduction of -12% in peak flows.

09_499_3_RPS: Significant flooding occurs upstream of this HEP, with flood water not returning to the channel and therefore causing a significant reduction in peak flows of -38.8%. Flood storage at Corkagh Park will also reduce the peak flows at this location.

09005_RPS: The difference of -31% is due to significant flooding upstream of this HEP along with a flood attenuation scheme at Corkagh Park. An extended receding limb is evident on the in channel hydrograph suggesting some attenuation of peak flows.

09035_RPS: The difference of -36% is due to significant flooding upstream of this HEP and flood attenuation at Corkagh Park. Upstream culvert capacities are significantly less than the hydrologically estimated peak flow. Truncated and extended hydrograph suggests that peak flows are being

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(3) Public Consultation Comments:

Please refer to Appendix A.2 for comments received on the draft final maps and potential options during the Public Consultation Phase.

(4) Standard of Protection of Existing Formal Defences:

Defence Type Watercourse Bank Modelled Standard of Reference Protection (AEP)

1 Corkagh Park Flood Camac NA NA Storage

2 DIAGEO Factory Camac Left >1% AEP Flood Defence wall

3 Robinhood Industrial Kilnamanagh Left <1% AEP Estate flood defence and wall Walkinstown

4 Lady's Lane Flood Camac Right >1% AEP defence wall

The figure above illustrates the location of the Corkagh Park Ponds (1)

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The figure above illustrates the location of the DIAGEO (2) and Robinhood (3) Industrial Estate existing defences

The figure above illustrates the Location of the Lady's Lane existing defences (4)

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(5) Other Information:

(a) Camac River, Clondalkin, South County Dublin; Mark O'Reilly and Associates, November 1995.

(b) Report on Camac Flooding 11th-12th June, 1993;

(c) Report on Camac River Improvement Scheme, Phase 1, Newlands-Fonthill to Nangor Road, Clondalkin; Drainage New Works-Design Section September 1993.

(d) Urban River Management, National Hydrology Seminar; Sean Murray, Senior Engineer, South Dublin City Council, November 2000.

(e) Local Authority comments from DCC and SDCC on specific known areas of flooding and the mechanisms causing the flooding.

4.5.5 Sensitivity Analysis

A number of sensitivity tests have been completed in accordance with Guidance Note 22 to assess the impact of adjusting various parameters within the hydraulic model. The tests undertaken were:

(a) Structure Sensitivity; discharge coefficients at critical structures were adjusted to assess the impact on water levels in the vicinity of the structure. The structures chosen were considered to have potential to contribute significant additional damage if they are determined to be sensitive to a change in the discharge coefficient. The table below presents the adjusted parameters for each run and the resultant difference in water levels in the vicinity of the structure.

Structure Location Design Run - Headloss Sensitivity Run - Resultant US water Coefficient Headloss Coefficient level change (m)

Bow Bridge 0 2 0.221

Kearns Place Bridge 0 2 0.14

Woodford Walk Bridge 0 2 0.186

N7 Underpass Culvert 0.3 1 0.006

The diagram below illustrates the impact on flood extents as a result of the change in the discharge coefficients at Bow Bridge and Kearn's Place Bridge. Although only minor increases in flood extents are evident from the diagram below, the flood depths in the vicinity of the structures have increased in line with the water level changes noted in the table above. It is therefore likely that a significant increase in damages would occur.

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Bow Bridge

Kearns Place Bridge

The diagram below illustrates the impact on flood extents as a result of the change to the discharge coefficient at Woodford Walk Bridge. The diagram indicates a significant increase in the flood extent and the number of properties potentially at risk of flooding.

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Woodford Walk Bridge

No significant additional flooding occurs in the vicinity of the N7 underpass culvert.

(b) Roughness Sensitivity

Floodplain roughness was increased to upper bound values as presented in the table below, while 1D roughness values were increased by 20%.

Roughness Zone Description Design Run Manning's n Sensitivity Test Manning's n

Industrial and commercials units 0.014 0.02

Road and Rail Network 0.013 0.017

Continuous Urban Fabric 0.011 0.017

Discontinuous Urban Fabric 0.045 0.055

Green Urban Areas 0.03 0.04

Airports 0.013 0.017

Complex Cultivation Patterns 0.04 0.05

Coniferous Forest 0.06 0.07

Non-irrigated arable land 0.035 0.045

Sport and Leisure Facilities 0.03 0.04

Pastures 0.035 0.045

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Transitional Woodland Scrub 0.06 0.07

The diagrams below illustrate the impact of increasing the in-channel and floodplain roughness values in the Camac catchment. The increase in flood extents is more pronounced in areas of flat floodplain, with a significant number of additional properties potentially at risk in the vicinity of the M50.

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The downstream boundary condition was changed to the value predicted for the medium range future scenario. This value was generated by applying climate change flow values to the Lower Liffey ECFRAM computational model along with an allowance for sea level rise at the downstream boundary of the Liffey model. As would be expected the effect of the boundary change was limited to the downstream extent of the Camac as shown in the diagram below.

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(d) Flow Sensitivity

In line with GN22 a 20% increase was applied to the 10% AEP flows to assess the sensitivity of flooding in the Camac catchment. The diagrams below illustrate the comparison between the 10% design event flooding and the 10% sensitivity event flooding. Comparison of the extents indicates relatively minor increases in flooding in urbanised areas.

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The 1% AEP MRFS model was used to provide an indication of the sensitivity of the Camac catchment to an increase in flows. The MRFS model results were used as the factors applied to take account of climate change were comparable to the value calculated using the methodology described in GN22. The diagram below provides an overview of the increase in flood extents due to the applied increase in flow values. The diagram indicates a significant increase in flooding throughout the catchment with additional properties being at risk in numerous locations.

The sensitivity analysis indicated that the model is relatively sensitive to changes in the various parameters. An increase in rainfall and the subsequent increase in flows presented the most variation in flood extents, with even a 20% increase causing a significant increase in potential flood risk throughout the catchment.

Although the sensitivity tests indicate that changes in model parameters could significantly influence the model output, calibration results provided a good correlation with available recorded flood levels and extents. The model provided a good representation of the flooding experienced during a recent extreme flood event, with an estimated magnitude of 2% -1% annual exceedance probability. This provides confidence that the model is generating reliable results for events of this magnitude and therefore the model parameters utilised to simulate design events are a good representation of the hydraulic behaviour of the watercourse and catchment.

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4.5.6 Hydraulic Model Assumptions, Limitations and Handover Notes

(1) Hydraulic Model Assumptions:

(a) Please refer to main report for general assumptions using the InfoWorks ICM modelling software.

(b) It is assumed that all informal and formal defences are effective.

(c) Specific roughness data was not available for all culverts, a conservative value was therefore applied where no data was available.

(d) It is assumed that incidental defences (i.e. boundary walls) are ineffective and have no influence on flow paths.

(e) Given the urban nature of, and development pressure in, the catchment, it remains possible that incidental or possible informal defences might be altered resulting in a moderate possibility that alternative flood flow routes bypass these constraints.

(f) For design run simulations it has been assumed that all culverts and screens are free of debris and sediment.

(g) No specific afflux data was available for calibration of headloss across bridges, as such all bridge coefficients have been left at default values.

(h) Corkagh Park has been modelled using a 2D mesh, it has been assumed that the water level defined in the LiDAR DTM is normal water level for the ponds and any additional storage provided is above this level.

Incorporation of Flood Defence Proposed Options

(a) Flood Defence Walls and Embankments – proposed flood defence walls have been incorporated into the 2D mesh using porous walls with infinite crest levels and zero porosity. The location of the walls and embankments included in the models are illustrated in the diagrams below, the number displayed beside each of the defence items indicates the maximum height, including freeboard, of the wall or embankment required at that location. Locations of manholes which are proposed to be sealed to prevent flooding via the drainage system have also been shown on the diagrams below.

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South Circular Road to Bow Lane

Lansdowne Valley Park to South Circular Road

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Robinhood Industrial Estate

Nangor Road

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Woodford Walk

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Moneenalion Commons Lower

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Baldonnell Little

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Kingswood (Fortunestown and Tallaght Rivers)

Saggart (Vershoyles River)

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Greenoge Business Park

The table below provides an overview of the length of defences required.

ID Bank Watercourse Start Chainage End Chainage

(approx) (approx.)

924000, 924001, Left and Right Vershoyles 2380 2200 924002

924003 Left Vershoyles 1490 1470

924004 Right Vershoyles - Vershoyles 70 Camac 13120 Camac

924005 Left Camac 14960 14270

924006 Left Camac 13320 12920

924007 Left Camac 12920 12590

924008 Right Fortunestown 1435 1330

924009 Left and Right Fortunestown 1000 980

924010 Left and Right Fortunestown 920 830

924011 Left Fortunestown 220 160

924012 , 924013 Right Fortunestown 160 30

924014 Left Tallaght 660 630

924015 Left Tallagh 740 695

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ID Bank Watercourse Start Chainage End Chainage

(approx) (approx.)

924016 Right Camac 12040 11940

924020, 924020 Left and Right Camac 8090 7950

924022 Right Camac 7750 7600

924023 Right Camac 7550 7500

924024 Left Camac 7430 7360

924025 Left and Right Camac 7290 6980

924026 Left and Right Camac 6900 6770

924027 Right Camac 6440 6170

924028 Left Camac 6530 6380

924029 Right Camac 5280 5200

924030 Right Camac 5000 4960

924031 Left Camac 2815 2650

924033 Right Camac 2840 2750

924034 Right Camac 2420 2320

924035 Right Camac 2280 2145

924036, 924070, Right Camac 1775 1575 924071

924037 Right Camac 1490 1470

924039 Left Camac 1400 1310

924040 Right Camac 1230 1070

924041, 924062, Left and Right Camac 1060 670 924063, 924064, 924065, 924069, 924068, 924067, 924066, 924042

924043 Left Camac 1060 1030

924044 Right Camac 650 510

924045 Left Kilnamanagh - Kilnamangh 290 Walkinstown130 Walkinstown

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ID Bank Watercourse Start Chainage End Chainage

(approx) (approx.)

924046 Right Walkinstown 230 180

924047 Right Kilnamanagh 190 80

924048 Right Kingswood 770 740

924049 Right Kingswood 114 850

924050 Left Kingswood 1070 840

924051 Left Walkinstown 110 40

924052 Right Walkinstown - Walkinstown 60 Kingswood 540 Kingswood

924053 Left and Right Kingswood 510 420

924055 , 924031 Left Camac 2870 2640

924032, 924057, Left and Right Camac 2640 2440 924058, 924061, 924060, 924059

(b) Landsdowne Valley Park was identified as a potential storage area using the existing topography of the park and controlling flow through the Grand Canal embankment. The bund structure required to provide the storage was simulated using a mesh polygon with ground levels increased to alter the topography of the park. An orifice unit was included with invert level equivalent to the existing bed levels to maintain low flows. An overflow weir was also included to control the peak water level within the storage area.

(c) A diversion option was investigated with an abstraction point located in the vicinity of St. Patricks Athletic Football Club on Emmet Road. The route of the diversion culvert crossed Inchicore Road to Con Colbert Road, and then through to the sports grounds adjacent to the National War Memorial where it descended to the River Liffey. The diversion was modelled using an over-flow side-weir inlet, with conduit sections separated by manholes, through to its discharge point, which is upstream of the weir near UCD boat club. The option was ruled out on economic and technical grounds.

(d) Additional storage at Corkagh Park was identified as a potential option to reduce flow entering the more densely urbanised reaches of the Camac River. An attenuation scheme is already in place in Corkagh Park. The Camac River spills to a number of attenuation ponds and channels during high flows. The additional storage option proposal was intended to increase the area of Corkagh Park used for attenuation introducing an inline structure to regulate flow and a bund structure to contain flood water within the parkland.

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(e) Dredging of the Camac River was modelled by lowering the bed levels of all sections between its confluence with the Liffey and Landsdowne Park. The gradient of the channel was maintained with all bed levels being lowered 2m, no adjustment to channel width or composition was made. The model results indicated that dredging this portion of the Camac could reduce the overall length and height of the flood defences walls and embankments which would be required. However due to the amount of associated works (under-pinning of bridges, lowering of culverts, stabilisation of nearby properties and removal/disposal of dredge material) required for this option it was deemed unfeasible.

(f) Removal of bridge parapets was modelled by lowering the bridge spill to the appropriate level enabling flood water to spill over the bridge at a lower level. The hydraulic model was altered to remove the parapets of Bow Bridge and Kearn's Place Bridge. Removal of the Bow Bridge parapet reduced water levels by approximately 400mm as far upstream as Kearn's Place. Removal of the Kearn's Place Bridge parapets reduced water levels upstream and reduced the height and length of wall required. However removal of this parapet increased the water levels downstream.

The option appraisal carried out for the Camac catchment did not find a cost beneficial option for the catchment as a whole, a more detailed study will be required to investigate possible flood alleviation measures for specific locations within the catchment.

Please refer to IBE0600Rp0031 Eastern CFRAM Study Camac Options Report, for further details on the options considered along with the economic implications of each.

(2) Hydraulic Model Limitations:

(a) Only one low flow gauging station was available to provide flow/stage calibration.

(b) A variable timestep with a maximum value of 1 second has been applied to the 1D domain of this model to achieve a successful model simulation.

(c) Streets and roads have generally been defined by the inclusion of impermeable buildings in the 2D mesh. Consultation with Local Authorities, OPW and the Public did not highlight that flow paths or flooded areas had been excluded due to roads not being expressly delineated and the model is considered to be well calibrated to approximately the 1% AEP event.

(3) Design Event Runs and Hydraulic Model Handover Notes:

(a) No drainage networks are included in the computational model, as such all flows have been introduced directly to the 1D channel as point or lateral inflows. Flooding has been reported to originate from both the main river network and the urban drainage network, only flooding coming directly from the main river network has been modelled.

(b) Generally, other than buildings, only floodplain structures which were identified as being formal or informal effective defences have been included in the model due to the uncertainty towards the capacity of un-engineered structures to retain water. As such in certain instances flow paths and flooded areas differ

IBE0600Rp00027 53 F01 Eastern CFRAM Study HA09 Hydraulics Report – DRAFT FINAL from those recorded during past flood events.

(c) Flooding and flood flow in the Camac River is influenced by a number of in-channel structures including sluice gates, conduits and storage.

(d) Significant flooding is predicted along the right bank of the Camac River downstream of the South Circular Road Bridge during the 1% AEP event. Faulkner's Terrace, Kearn's Place and Shannon Terrace being the worst affected, a number of these properties are also predicted to be at risk during the 10% AEP event, Bow Bridge and Kearn's Place Bridge both increase the risk of flooding along this reach. The collapse of a wall in the vicinity of Lady's Lane during the October 2011 event increased the flooding in this area. Dublin City Council have since installed an engineered flood wall to provide protection against a 1% AEP event. From Lansdowne Valley Park to the South Circular Road Bridge a number of properties are predicted to be at the risk of flooding, with properties along Tyrconnell Road and Emmet Road potentially at risk during the 10% AEP event. In the Woodford Walk and Nangor Road area significant flooding is predicted during the 1% AEP event however no significant flooding is expected during the 10% AEP event. Blockages of bridges and culverts was identified as exacerbating flooding in some areas. During the October 2011 event, a partial blockage of the bridge at Woodford Walk was reported by residents as causing flooding, with further flooding only negated by the residents removing the blockage.

(e) A number of commercial properties in the Robinhood Industrial Estate which has a reach of flood defence wall along the Walkinstown Stream are predicted to be at risk of flooding. The flood defences are predicted to be bypassed by the 1% AEP event. Flooding is also predicted from the Kingswood Stream which will affect a number of properties in this area during the 10% AEP event.

(g) A large area of flooding is predicted on the left bank of the Camac downstream of the N7 during the 1% AEP event. This flooding was not verified by historical data or anecdotal evidence. Photographic evidence suggests that the river banks in this area may have been altered during agricultural activities which have lowered the banks sufficiently to allow a prolonged discharge of flood water to leave the channel during the 1% AEP event.

(h) A number of properties are predicted to be at risk of flooding in the Saggart and Commons areas from the Vershoyles River. The flooding is predicted to occur from a 600mm culvert inlet adjacent to Carrigmore Avenue.

(4) Model Deliverables:

Model deliverables are supplied in an accompanying InfoWorks ICM transportable database containing all model results files as required by the brief and the relevant network and event files. (5) Conclusions:

A 1D/2D flexible mesh ICM model has been generated of the Camac HPW catchment which utilises appropriate supplementary datasets from the GDSDS to better represent extended culverted reaches.

This model is considered well calibrated given that an event of 1-2%AEP was experienced and relatively well documented in October 2011 and supplemented by information on other fluvial events recorded since the 1980s.

One gauging station, located within the modelled extents, was used during both the hydrological analysis

IBE0600Rp00027 54 F01 Eastern CFRAM Study HA09 Hydraulics Report – DRAFT FINAL and hydraulic model calibration. A good correlation was achieved between the modelled stage discharge relationship and the spot gaugings at the gauging station.

Flooding is predicted to occur at a number of locations throughout the catchment with numerous properties potentially at risk of flooding. In many cases the predicted flooding has been verified by the flood event which occurred in Oct 2011. Comments made on the public consultation/stakeholders workshops at the draft mapping stage further supported model calibration and the understanding of flood mechanisms in this HPW.

Three sets of hard flood defences are located within the modelled reach, two of which have been predicted to be effective to above the 1% AEP event (Diageo and Lady's Lane) and one which is predicted to be ineffective during a 1% AEP event (Robinhood Industrial Estate).

A sensitivity analysis has been undertaken to understand the significance of design assumptions and model parameters used in the analysis. The sensitivity tests indicated that the model is relatively sensitive to changes in model parameters and input data.

Some areas in the lower reaches of the modelled catchment are known to be susceptible to both fluvial and pluvial flooding leading to some ambiguity with the source of flooding in historic recorded flood extents. Further analysis is recommended to investigate fully the flooding mechanisms in the catchment.

(6) Quality Assurance: Model Constructed by: Andrew Sloan

Model Reviewed by: Andrew Jackson

Model Approved by: Grace Glasgow

IBE0600Rp00027 55 F01

APPENDIX A.1

Structure Details - Bridges Spring Height Bridge from RIVER Opening Height Width Invert MANNINGS BRANCH CHAINAGE ID LENGTH Shape (m) (m) (m) N Camac 19750 Br01975D US 2.6 Rectangular 0.8 3.88 NA 0.05 Camac 18410 Br01841D US 6.7 Arch 3.5 3.66 1.9 0.025 Camac 18110 Br01811D US 1 Rectangular 0.9 3.8 NA 0.025 Camac 16910 Br01691D US 2.6 Rectangular 1.2 2.21 NA 0.025 Camac 16840 Br01684 US 9.2 Arch 1.8 3.48 0 0.05 Camac 16260 Br01626D US 4.7 Rectangular 1.3 3.5 NA 0.05 Camac 15630 Br01563D US 16.5 Arch 1.65 3.09 0.65 0.055 Camac 15120 Br01512D US 5.7 Rectangular 2.65 4.37 NA 0.05 Camac 14240 Br01424D US 3.3 Rectangular 1.73 3.4 NA 0.025 Camac 13980 Br01398D US 1.7 Rectangular 3.3 9.87 NA 0.025 Camac 13320 Br01332D US 7.1 Rectangular 1.4 6 NA 0.025 Camac 13280 Br01328D US 4.1 Rectangular 1.3 6 NA 0.025 Camac 13220 Br 01322D US 3.6 Rectangular 1 6 NA 0.025 Camac 13200 Br01320 US 5 Rectangular 0.8 5.4 NA 0.025 Camac 12590 Br01259D US 7.1 Arch 1.8 3.99 1 0.055 Camac 12320 Br01232D US 3.6 Rectangular 2.05 4.24 NA 0.025 Camac 11860 Br01186E US 7.1 Arch 1.66 3.01 1.12 0.025 Camac 11580 Br01158D US 4.7 Arch 1.87 3.09 1.3 0.025 Camac 11210 Br01121D US 6 Arch 1.9 4.7 0.95 0.055 Camac 10920 Br01092D US 5.4 Arch 1.85 5.46 1.7 0.055 6.3 Rectangular 0.7 2.88 NA 0.055 Camac 10700 Cu01070I US 6.3 Rectangular 1.278 2.77 NA 0.055 Camac 10340 Br01034D US 2.7 Rectangular 1.4 9.13 NA 0.025 Camac 9680 Br00968D US 4.3 Rectangular 3 7.5 NA 0.025 Camac 9630 Br00963d US 8.5 Rectangular 2.72 6.93 NA 0.025 Camac 9350 Br00935D US 1 Rectangular 1.96 6 NA 0.055 Camac 9230 Br00923D US 4.7 Rectangular 2.27 7.92 NA 0.055 Camac 8810 Br00881D US 5.1 Rectangular 3.31 4.81 NA 0.05 6.8 Rectangular 1.8 2.6 NA 0.05 Camac 8630 Cam863DS 6.8 Rectangular 1.8 2.6 NA 0.05 8.4 Rectangular 1.95 2.48 NA 0.05 Camac 8510 cam00851 DS 8.4 Rectangular 1.95 2.48 NA 0.05 14.2 Rectangular 2.12 3.26 NA 0.05 Camac 8180 cam0818 DS 14.2 Rectangular 2.12 3.26 NA 0.05 16.3 Rectangular 1.82 3.3 NA 0.04 Camac 7950 Br00795_US 16.3 Rectangular 1.82 3.3 NA 0.04 14.4 Rectangular 2 4.35 NA 0.05 Camac 7860 Camm0786_Br_break 14.4 Arch 3.4 12.5 NA 0.045 Camac 6600 Camm00660_Br_break_us 2.8 Rectangular 2.35 8.8 NA 0.055 Camac 6460 Camm00646_br_break_us 1.7 Rectangular 2.6 12 NA 0.05 Camac 6400 Camm0640_br_us 1.9 Rectangular 1.4 4.15 NA 0.05 Camac 4140 Br00414D US 2.1 Arch 4.98 14.5 4.87 0.025 Camac 2770 Br00277 US 11.4 Arch 3.03 3.27 2.1 0.025 Camac 2440 Br00244D US 18.7 Arch 3.8 4.84 2.5 0.04 Camac 1820 PC00182 US 1 Rectangular 0.9 4.84 NA 0.04 Camac 1700 PC00170 US 1 Rectangular 1.35 8.58 NA 0.04

Camac 1470 Br00147D US 18.9 Arch 5.01 5.95 2.6 0.025 Spring Height Bridge from RIVER Opening Height Width Invert MANNINGS BRANCH CHAINAGE ID LENGTH Shape (m) (m) (m) N Camac 1240 Br00124D US 6.5 Rectangular 1.8 10 NA 0.025 Camac 1050 BR00105_break_us 5.2 Rectangular 1.828 9 NA 0.025 16.5 Arch 2.87 4.85 0.5 0.025 Camac 670 Br00067D US 16.5 Arch 2.81 4.81 0.5 0.025

Saggart 1250 09SAGA00125_BR_BREAK_US 2.1 Rectangular 0.825 1.97 NA 0.05 Saggart 700 09SAGA00070BR_BREAK_US 4.1 Rectangular 0.425 2 NA 0.05

Saggart 520 09SAGA00052_BR_BREAK_US 14.1 Rectangular 1.5 1.7 NA 0.05 Fitzmaurice 520 Fitz00052D US 1.4 Rectangular 0.65 4.4 NA 0.025 Vershoyles 3200 Vers00320D US 24 Rectangular 6 2.07 NA 0.025 Vershoyles 3030 Vers00303D US 26.7 Arch 2.5 2.2 2 0.025 Fortunestown 2000 Br0200 US 2.5 Rectangular 1.83 4.3 NA 0.025 10.7 Rectangular 0.84 0.59 NA 0.025 Fortunestown 160 FortBr0016D US 11.5 Rectangular 0.78 0.78 NA 0.025 4.4 Circular 0.3 0.3 NA 0.05 Tallaght 940 09TALLA0094_BR_BREAK_DS 4.4 Circular 0.3 0.3 NA 0.05 Tallaght 900 09TALLA0090_BR_BREAK_DS 1.4 Rectangular 1 4.8 NA 0.05 7.8 Circular 0.3 0.3 NA 0.05 Tallaght 890 09TALLA0089_BR_BREAK_US 7.8 Circular 0.3 0.3 NA 0.05 3.4 Circular 0.45 0.45 NA 0.05 Tallaght 830 09TALLA0083_BRIDGE_BREAK_US 3.4 Circular 0.45 0.45 NA 0.05 6.1 Circular 0.45 0.45 NA 0.05 Tallaght 770 09TALLA0077_BRIDGE_BREAK_US 6.1 Circular 0.45 0.45 NA 0.05 3.3 Circular 0.45 0.45 NA 0.05 Tallaght 720 09TALLA0072_BRIDGE_BREAK_US 3.3 Circular 0.45 0.45 NA 0.05 15.8 Rectangular 1.5 1.38 NA 0.05 Walkinstown 130 09WALK00013_BR_US 15.8 Rectangular 1.5 1.67 NA 0.05 Kingswood 540 09KING00054_BR_US 34.9 Rectangular 1.5 2.6 NA 0.05 Kingswood 470 09KING00047_BR_US 9 Rectangular 2.15 6.4 NA 0.05 Crumlin 340 Crum00034D US 1.9 Rectangular 1.08 4.19 NA 0.025 Crumlin 250 Crum00025D US 1.9 Rectangular 1 3.39 NA 0.025 Crumlin 190 Crum00019D US 1.8 Rectangular 1 3.39 NA 0.025 Crumlin 40 Crum00004DUS 1.9 Rectangular 1.1 5.5 NA 0.025

Structure Details - Culverts Spring Height from COLEBROOK Opening Invert WHITE Ks (unless RIVER BRANCH CHAINAGE ID LENGTH (m) Shape Height Width (m) otherwise stated) Camac 200080 09CAMM02008D US 7 Rectangular 0.6 1 NA 15 Camac 19870 C01987I US 14.8 Arch 2.23 3.55 1.5 5.7 Circular 0.25 0.25 NA 0.3 5.7 Circular 0.9 0.9 NA 0.3 Camac 18000 Cu1800 US 5.7 Circular 0.25 0.25 NA 0.3 11.6 Circular 0.9 0.9 NA 0.3 Camac 17520 Cu1752 US 11.6 Circular 0.6 0.6 NA 0.3 Camac 16690 Cu01669I US 4.9 Circular 1.5 1.5 NA 0.3 Top Manning's n 0.012 Bottom Camac 15680 Cu01568I US 9.5 Rectangular 1.3 2.73 NA Manning's n 0.04 Camac 15490 UN_Trib_Camac_20 247 Rectangular 1.55 3.35 NA 0.3 Top Manning's n 0.03 Bottom Camac 13860 Cu01386 US 52.2 Arch 1.9 2.33 1.28 Manning's n 0.04 Camac 13360 Cu01336I US 7.8 Rectangular 1.5 3 NA 0.3 Camac 12270 Cu01227I US 50.5 Arch 2.89 6.32 1.65 0.3 11 Circular 1.3 1.3 NA 0.3 Camac 11750 Cu01175I US 11 Circular 1.3 1.3 NA 0.3 17.3 Rectangular 2.08 2.6 NA 0.3 17.3 Rectangular 2.11 4.05 NA 0.3 Camac 9940 Cu00994I US 17.3 Rectangular 2.11 2.64 NA 0.3 8.5 Circular 1.2 1.2 NA 0.3 Camac 9610 Cu00961 US 8.5 Circular 1.2 1.2 NA 0.3 Camac 9040 Cu00904I US 184.3 Arch 2.16 4.81 1.42 0.3 Manning's n Camac 7500 CU14 US 72 Rectangular 2.15 3.47 NA 0.012 Manning's n 70.5 Arch 1.99 2.8 0 0.012 Manning's n Camac 6980 Cu13 US 70.5 Arch 2.04 3.06 0 0.012 Manning's n 76.2 Arch 1.53 2.05 0 0.012 Manning's n 76.2 Arch 1.8 2.22 0 0.012 Manning's n Camac 6770 Cu12 US 76.2 Arch 1.53 2.05 0 0.012 Manning's n Camac 6600 Cu11 US 17.1 Rectangular 2.33 4.84 NA 0.012 Manning's n Camac 6380 CamXs638‐MhCu10a 195 Rectangular 1.6 5.43 NA 0.012 Camac 6270 Camm00627_Break 44 Rectangular 4.4 4.4 NA 1.5 Manning's n Camac 6220 Camm_622_cul_us 1169.9 Rectangular 1.6 5.43 NA 0.012 Manning's n Camac 5200 CamXs520‐Cu09 62.2 Rectangular 3.43 3.24 NA 0.012 Manning's n Camac 4790 CamXs459_MhCu08 614.8 Arch 3.71 2.9 2.5 0.012 Camac 3250 Cu00325I US 77.5 Arch 3.15 7.07 0.15 0.3 Rectangular 2.9 3.75 NA 0.3 Camac 3030 Cu00303I US 161.5 Rectangular 2.94 3.7 NA 0.3 Camac 2750 Cu00275I US 26.2 Rectangular 3.17 3.92 NA 0.3

Spring Height from COLEBROOK Opening Invert WHITE Ks (unless RIVER BRANCH CHAINAGE ID LENGTH (m) Shape Height Width (m) otherwise stated) 20.3 Arch 2.05 5.11 0.91 0.3 Camac 470 Cu00047I US 20.3 Arch 2.05 5.11 0.91 0.3 Camac 270 Cu00027I US 150 Arch 2.59 5.85 0.1 0.3 Saggart 1600 09SAGA00160_CUL_US 19.3 Circular 1 1 NA 1.5 Saggart 1570 09SAGA00157_CUL_US 6.4 Circular 0.9 0.9 NA 1.5 Saggart 1270 09SAGA00127_CUL_US 5.1 Rectangular 0.7 0.9 NA 1.5 Saggart 950 09SAGA00095_CUL_US 16.9 Circular 0.9 0.9 NA 1.5 Millrace 40 Milj 00004I US 12.4 Circular 0.45 0.45 NA 0.3 Link 130 Link00013I US 12.6 Circular 0.6 0.6 NA 0.3 Link 430 Link00043J US 7.8 Circular 1 1 NA 0.3 Vershoyles 2190 Vers00219 US 480 Circular 0.6 0.6 NA 0.3 Vershoyles 1600 Vers00160I US 15.2 Rectangular 1.19 2.5 NA 0.3 18.8 Circular 0.3 0.3 NA 0.3 Vershoyles 1490 Vers00149I US 18.8 Circular 0.3 0.3 NA 0.3 82.7 Circular 1.2 1.2 NA 0.3 Vershoyles 1440 Vers00144I 82.7 Circular 1.2 1.2 NA 0.3 120.1 Circular 1.2 1.2 NA 0.3 Vershoyles 1110 Vers00111I 120.1 Circular 1.2 1.2 NA 0.3 Vershoyles 980 Vers00098I US 20.7 Rectangular 0.95 1.75 NA 0.3 Vershoyles 860 Vers00086I US 54.1 Rectangular 1.59 1.1 NA 0.3 Vershoyles 470 Vers00047I US 4.8 Rectangular 1.02 1.77 NA 0.3 Vershoyles 360 Vers00036I US 4.7 Rectangular 1.1 1.98 NA 0.3 Vershoyles 90 Vers00009I 48.5 Circular 0.9 0.9 NA 0.3 Vershoyles 40 Vers00004I US 30 Circular 0.9 0.9 NA 0.3 City West 90 West 00009I US 14.8 Circular 0.5 0.5 NA 0.3 City west 0 West DS 8.1 Circular 0.3 0.3 NA 0.3 City West 0 SD009I_22 529.1 Circular 1.05 1.05 NA 1.5 Fortunestown 2720 Cu0272 In 137.3 Rectangular 0.8 1.7 NA 0.3 Fortunestown 2510 Cu251 Us 20.9 Rectangular 1.26 2 NA 0.3 Fortunestown 2300 Cu0230 US 14 Circular 0.9 0.9 NA 0.3 Fortunestown 2190 Cu0219 US 29.6 Rectangular 0.97 1.92 NA 0.3 Fortunestown 1810 Cu0181 US 29.4 Rectangular 1.02 2.04 NA 0.3 Fortunestown 1760 Cu0176 US 163.4 Rectangular 1.54 3.1 NA 0.3 Fortunestown 1300 Cu0130 US 20.8 Rectangular 1.16 3 NA 0.3 Fortunestown 980 Cu0098 US 1.1 Rectangular 0.9 2.84 NA 0.3 80.9 Rectangular 0.55 1.13 NA 0.3 Fortunestown 590 Cu0059 US 80.9 Rectangular 0.64 0.74 NA 0.3 Fortunestown 570 Cu0057 US 8.9 Circular 0.7 0.7 NA 0.3 Fortunestown 450 Cu0045 US 6.7 Circular 1 1 NA 0.3 4.4 Circular 0.6 0.6 NA 0.3 Fortunestown 240 FortCu0024 US 4.4 Circular 0.45 0.45 NA 0.3 9.7 Circular 0.73 0.73 NA 0.3 Fortunestown 150 FortCu0015 US 9.7 Circular 0.73 0.73 NA 0.3 5.6 Rectangular 0.82 0.59 NA 0.3 Fortunestown 70 Fort00007I US 5.6 Rectangular 0.73 0.73 NA 0.3 Tallaght 1440 09TALLA00144_BREAK 2745 Rectangular 1.5 1.8 NA 0.6 2.7 Circular 0.45 0.45 NA 1.5 Tallaght 680 09TALLA0068_CULVERT_BREAK_US 2.7 Circular 0.45 0.45 NA 1.5 Tallaght 630 09TALLA0063_CULVERT_BREAK_US 12.8 Circular 2.05 2.05 NA 1.5 Tallaght 560 09TALLA0056_CULVERT_BREAK_US 16.1 Rectangular 1.06 1.69 NA 1.5

Spring Height from COLEBROOK Opening Invert WHITE Ks (unless RIVER BRANCH CHAINAGE ID LENGTH (m) Shape Height Width (m) otherwise stated) Tallaght 490 09TALLA0049_CULVERT_BREAK_US 86 Rectangular 1.6 1.68 NA 1.5 Tallaght 170 09TALLA0017_CULVERT_US 95.7 Circular 2.05 2.05 NA 1.5 Cheeverstown 130 09CHEE0013_CUL_US 50.8 Circular 1.8 1.8 NA 1.5 65 Circular 1.2 1.2 NA 1.5 Cheeverstown 100 CHEE_DS 65 Circular 1.2 1.2 NA 1.5 Kingswood 3540 09King00354_CUL_US 325.5 Circular 1.3 1.3 NA 1.5 Kingswood 2280 09King00228_CUL_US 755.3 Rectangular 1.63 1.6 NA 1.5 Manning's n Kingswood 1360 09King00136_CUL_US 42 Arch 1.89 2.43 0 0.012 Manning's n Kingswood 740 09King00074_CUL_US 110.1 Rectangular 0.934 2.62 NA 0.012 Kingswood 0 King DS 79 Rectangular 2 3.35 NA 0.3 Kilnamanagh 1820 09KILN00182_CUL_US 1554.9 Rectangular 1.2 2 NA 1.5 8.8 Circular 1.05 1.05 NA 1.5 Walkinstown 190 09WALK00019_CUL_US 8.8 Circular 0.6 0.6 NA 1.5 Crumlin 130 Crum00013I US 15.3 Rectangular 1.5 1.5 NA 0.3

Structure Details - Weirs

Camac 6420 Wr642 US_Gauging_Station Broadcrested

Camac 17890 Wr01789W US Broadcrested

Camac 16770 Wr01677W US Broadcrested

Camac 16390 Wr01639W US Broadcrested

Camac 15970 Wr01597W Broadcrested

Camac 15810 Wr01581 US Broadcrested

Camac 15770 Wr01577 US Broadcrested

Camac 15180 Wr01518W US Broadcrested

Camac 11450 Wr01145W US Broadcrested

Camac 11370 Wr01137W US Broadcrested

Camac 10890 Wr01089W US Broadcrested

Camac 9660 Wr00966 US Broadcrested

Camac 9540 Wr00954 US Broadcrested

Camac 9420 Wr00942 US Broadcrested

Camac 9400 Wr00940 US Broadcrested

Camac 9180 Wr00918 US Broadcrested

Camac 8820 Wr00882 US Broadcrested

Camac 3890 Wr00389 US Broadcrested

Camac 3730 Wr00376 US Broadcrested

Camac 2810 Wr00281 US Broadcrested

Camac 2630 Wr00263 US Broadcrested

Camac 7410 Camm00741_weir_us Broadcrested

Saggart 40 09SAGA0004_WEIR_US Broadcrested

Millrace 120 Milj00012W US Broadcrested

Fitzmaurice 680 09FITZ00068_WEIR_US Broadcrested

Fitzmaurice 630 09FITZ00063_WEIR_US Broadcrested

Fitzmaurice 540 09FITZ00054_WEIR_US Broadcrested

Fitzmaurice 520 09FITZ00052_WEIR_US Broadcrested

Fitzmaurice 470 09FITZ00047_WEIR_US Broadcrested

Fitzmaurice 440 09FITZ00044_WEIR_US Broadcrested

Fitzmaurice 410 Fitz00041W US Broadcrested

Fitzmaurice 390 Fitz00039W US Broadcrested

Fitzmaurice 370 Fitz00037W US Broadcrested

Vershoyles 3150 Ver00315W US Broadcrested

Vershoyles 3130 Vers00313W US Broadcrested

Vershoyles 2960 Vers00296W US Broadcrested

Vershoyles 1620 Vers00162W US Broadcrested

Vershoyles 1570 Vers00157W US Broadcrested

Vershoyles 1450 Vers00145W US Broadcrested

Vershoyles 860 Vers00086W US Broadcrested

Camac 1770 Wr0177 US Broadcrested

Tallaght 170 09TALLA0017_WEIR_BREAK_US Broadcrested

Tallaght 650 09TALLA0065_WEIR_US Broadcrested

Tallaght 680 09TALLA0068_PIPE_BREAK Broadcrested

Tallaght 850 09TALLA0085_WEIR_US Broadcrested

Kingswood 2540 09KING00254_WEIR_US Broadcrested

Kingswood 2430 09KING00243_WEIR_US Broadcrested

Kingswood 2330 09KING00233_WEIR_US Broadcrested

Kingswood 660 09KING00066_WEIR_US Broadcrested

Crumlin 300 Crum00030W US Broadcrested

Crumlin 20 Crum00002W US Broadcrested

Camac 12270 Corkagh_Outlet Irregular

Camac 9440 WR00944 US Irregular

Camac 9240 Wr00924 US Irregular

Tallaght 700 09TALLA0070_WEIR_BREAK_US Irregular

APPENDIX A.2

PUBLIC CONSULTATION INFLUENCE

There were several comments made at the Camac consultation events (elected member briefings, public consultation days, Stakeholders Group Workshop), and via email / letter and telephone calls, in relation to the flood extents illustrated on the flood risk maps. Discrepancies were highlighted by consultees between the maps and the observed reality on the ground at a number of locations. However, investigation revealed that the majority of these discrepancies could be explained by factors which were not included within the flood mapping element of the project, such as blocked culverts, blocked bridges and surcharging drainage networks. In most cases, these mechanisms were acknowledged by consultees as being the source of the flooding. Therefore, no major amendments were made to the flood mapping model as a result of the comments received during the consultation process.

There was significant concern that no cost beneficial options were identified for the Camac catchment. However, most consultees understood that a holistic approach was required at this stage of the process, and that any option must provide protection to all flood risk properties in the catchment while providing a cost effective solution before it can be progressed.

As a result of the comments made and issues raised during the consultation process, the following additional investigations were carried out.

 Bow Bridge and Kearns Place Bridge were identified as structures causing restrictions that should be considered for removal or modification.

 It was suggested that lowering the bed level along the lower reach of the Camac should be considered.

 It was suggested that attenuation of the lower reach tributaries be considered.

 It was noted that properties flooded from the Bluebell stream during the October 2011 flood however this watercourse has not been included in the CFRAM study and should be included in future investigations.

Further details of the additional investigations mentioned above are contained within the Camac Options Report (IBE0600Rp0031_Camac Options Report).

APPENDIX A.3

Arbitrary Manhole Levels

Robinhood Stream Confluence to River Liffey

Some manhole cover level information which has been carried through from the GDSDS model for this reach has been set at an arbitrarily elevated level, this model assumption will not impact upon the model results. Future studies should acquire more accurate level information for these manholes.

Arbitrary Manhole Levels

Corkagh Park to Robinhood Stream Confluence

N7 to Corkagh Park

Upstream Boundary to N7