South Eastern CFRAM Study HA 15 Hydraulics Report 4.7 Callan

IBE0601Rp0015

rpsgroup.com/ireland

South Eastern CFRAM Study HA15 Hydraulics Report – DRAFT FINAL

South Eastern CFRAM

Study HA15 Hydraulics Report

Callan Model

DOCUMENT CONTROL SHEET

Client OPW

Project Title South Eastern CFRAM Study

Document Title IBE0601Rp0015_HA15 Hydraulics Report

Model Name Callan

Rev. Status Modeller Reviewed by Approved By Office of Issue Date Origin D01 Draft L. Howe I Bentley G. Glasgow Belfast 18/03/2014 /Limerick F01 Draft Final L. Howe K. Smart G. Glasgow Belfast 12/02/2015

F02 Draft Final L. Howe K. Smart G. Glasgow Belfast 13/08/2015

F03 Draft Final L. Howe S. Patterson G. Glasgow Belfast 29/06/2016

IBE0601Rp0015 F03 South Eastern CFRAM Study HA15 Hydraulics Report – DRAFT FINAL

Table of Reference Reports Relevant Report Issue Date Report Reference Section

South Eastern CFRAM November IBE0601 Rp0001_Flood Risk Review 3.3.4 Study Flood Risk Review 2011

South Eastern CFRAM Study Inception Report July 2012 IBE0601Rp0008_HA 15 Inception Report 4.3.2 UoM15

South Eastern CFRAM 1.1.1.1, October Study Hydrology Report IBE0601Rp0010_HA15_Hydrology Report 1.1.3.5, 2013 UoM15 1.1.5.4

South Eastern CFRAM January IBE0601Rp0016_South Eastern CFRAMS Study HA11-17 SC4 Survey 1.1 2014 Survey Contract Report Contract Report

4 Hydraulic Model Details ...... 1

4.7 Callan ...... 1

4.7.1 General Hydraulic Model Information ...... 1

4.7.2 Hydraulic Model Schematisation ...... 2

4.7.3 Hydraulic Model Construction ...... 11

4.7.4 Sensitivity Analysis ...... 21

4.7.5 Hydraulic Model Calibration and Verification ...... 21

4.7.6 Hydraulic Model Assumptions, Limitations and Handover Notes ...... 30

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4 HYDRAULIC MODEL DETAILS

4.7 CALLAN

4.7.1 General Hydraulic Model Information

(1) Introduction:

The South Eastern CFRAM Study Flood Risk Review report (IBE0601Rp0010_Flood Risk Review) highlighted Callan as an AFA for fluvial flooding based on a review of historic flooding and the extents of flood risk determined during the PFRA.

The Callan AFA (Model 6) incorporates the Kings River and associated tributaries including the Pawlerth River, Callan Link River and Skeaghacloran River. The Kings River joins the River Nore (Model 7 – Thomastown) from the west approximately 6 km upstream of Thomastown. The total contributing catchment area at the downstream extent of the model is 444 km2, with approximately 45% of this entering the model upstream of the AFA.

There are three gauging stations located along the length of the Callan model:

• Annamult (15001) – This gauge has an FSU rating of A2;

• Callan (15009) – This gauge has an FSU rating of B;

• Rathculbin (15023) – This gauge is inactive and has no flow or level data available.

Further information on these gauges is provided in Section 4.6.5. A CFRAM rating review was carried out for the Callan gauge (15009) in order to derive new values at the station. See section 4.9.5(b) for full review details.

A rainfall run-off model was constructed at the Callan gauge using rainfall radar data supplemented by hourly rainfall data at gauge 3613 in Kilkenny. It was calibrated against observed medium to low flows to increase confidence in the Qmed value and provide a median hydrograph shape. The resulting Qmed value is 40.78 m3/s. The Annamult gauge (15001) was not subject to hydrological modelling given the high degree of confidence in the gauge, including Qmed and hydrograph shape.

A number of rivers have been identified as HPWs within the Callan model, including Pawlerth River, Callan Link River, Callan Link B River (adjacent to Callan Link River) and the portion of the Skeaghacloran River and Kings River which pass through the AFA. These reaches have been modelled as 1D-2D using the MIKE suite of software. The remaining section of the Skeaghacloran River and Kings River is modelled as 1D, as it is designated as MPW.

On further inspection of survey data and aerial mapping, it was found that the Pawlerth River is blocked off at the downstream end of the watercourse (at the confluence with Kings River). Flow is diverted through

IBE0601Rp0015 4.7 - 1 F03 South Eastern CFRAM Study HA15 Hydraulics Report – DRAFT FINAL the Pawlerth into the Kings River upstream of the N76. Further detail of this is provided in Section 4.7.2(1).

(2) Model Reference: HA15_CALL6

(3) AFAs included in the model: CALLAN

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

Reach ID Name CALL CALLAN LINK

MLKA MULLAUNGLASS LINK A (renamed “Pawlerth Link”)

MLKB MULLAUNGLASS LINK B (renamed as the downstream extent of “Pawlerth River”)

PAWL PAWLERTH

KING CALLAN/KING GS

SHEA SKEAGHACLORAN

KING KINGS RIVER

(5) Software Type (and version):

(a) 1D Domain: (b) 2D Domain: (c) Other model elements: MIKE 11 (2011) MIKE 21 – Rectangular Mesh MIKE FLOOD (2011) (2011)

4.7.2 Hydraulic Model Schematisation

(1) Map of Model Extents:

Figure 4.7.1 and Figure 4.7.2 overleaf illustrate the extent of the modelled catchment, river centreline, HEP locations and AFA extents. The Kings catchment contains three Upstream Limit HEPs, one Downstream Limit HEP, 12 Tributary HEPs and two Gauging Station HEPs. There is no HEP at the location of the Rathculbin Gauging Station (15023) which is inactive and has no flow or water level data.

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Figure 4.7.1: Model of Map Extent

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Figure 4.7.2: Map of Model Extents at the AFA

Following a review of all survey data, including a culvert survey, it was found that two culverts in the Pawlerth River have been blocked off, namely 15PAWL00052I and 15PAWL00018. It is assumed that 15PAWL00052I (beneath the N76) and 15PAWL00018 (beneath Lower Bridge Street) were disconnected/blocked, and the link channel (Pawlerth Link) was created to divert flow into the Kings River. Surveyors advised that the channel between the two culverts is dry. The model has been developed based on these assumptions; the model extent is shown in Figure 4.7.3. This assumption was later confirmed by the Callan Area Engineer and subsequent survey.

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Pawlerth Link Pawlerth River 15PAWL00052I (Disconnected) Channel not represented in 1D model

15PAWL00018 (Disconnected)

Kings River

Figure 4.7.3 Model extent showing the disconnected culverts

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

River Name x y KING CALLAN LINK 242449.63 142886.49 KING CALLAN LINK B 242939.24 142723.59 PAWL PAWLERTH LINK 240951.6 144160.6 PAWL PAWLERTH 240784.81 145125.3 SHEA SKEAGHACLORAN 241661.94 145220.76 KING KINGS RIVER

240687 144114.06 (3) Total Modelled Watercourse Length: 25.0 (km)

(4) 1D Domain only Watercourse Length: 15.2 (km) (5) 1D-2D Domain 9.8 (km) Watercourse Length:

(6) 2D Domain Mesh Type / Resolution / Area: Rectangular / 5 metres / 10.5 km2

(7) 2D Domain Model Extent:

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Figure 4.7.4 2D Model Extent

Figure 4.7.4 represents the modelled extents and the general topography of the catchment within the 2D model domain. The 2D domain was generated using LiDAR survey data and created as a 5 m grid rectangular mesh. The river centreline is illustrated in black with black areas also representing the blocked cells, e.g. buildings. The area beyond the 2D model domain is illustrated in red. Changes in the vertical scale of this map are outlined by the index; all levels have been set to OD Malin (metres). For details of the approach to modelling buildings in the 2D area, please refer to Section 3.3.2 of this report.

Figure 4.7.5 shows the extent of the NDHM data used. The black line depicts the river network and the red boundary represents the LiDAR extent (as shown in Figure 4.7.4). A buffer zone was created between the two datasets which were smoothed together by interpolation.

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Figure 4.7.5 NDHM Extent

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Figure 4.7.6 shows an overview drawing of the model schematisation. Figure 4.7.8 and Figure 4.7.7: Overview of Model Schematisation provide detailed views. The overview diagram covers the model extents, showing the surveyed cross-section locations, AFA boundary and river centreline. It also shows the area covered by the 2D model domain. The detailed areas are provided where there is the most significant risk of flooding. These diagrams include the surveyed cross-section locations, AFA boundary and river centreline. They also show the location of the critical structures, as discussed in Section 4.7.3(1), along with the location and extent of the links between the 1D and 2D models.

Figure 4.7.6 Model Schematic Overview

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Figure 4.7.7: Overview of Model Schematisation

Figure 4.7.8: Model Schematisation of a reach of the Kings River, Skeaghacloran River and Pawlerth River

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(8) Survey Information

(a) Survey Folder Structure:

First Level Folder Second Level Folder Third Level Folder

CCS_S15_M06_15CALL_WP7_Final_1305 15CALL Data Files 23 15CALL Drawings Callan 15CALL GIS CCS: Surveyor Name Photos (Naming S15: South Eastern CFRAM Study Area, convention is in the Hydrometric Area 15 format of Cross-Section M06: Model Number ID and orientation -

15CALL: River Reference upstream, downstream,

WP4 : Work Package4 left bank or right bank) Version: Final

130523– Date Issued (23rd AUG 2013)

(b) Survey Folder References:

Reach ID Name File Ref.

CALL CALLAN LINK CCS_S15_M06_15CALL_WP7_Final_130523

MLKA MULLAUNGLASS LINK A CCS_S15_M06_15MLKA_WP2_Finals_130118

MLKB MULLAUNGLASS LINK B CCS_S15_M06_15MLKB _WP2_Finals_130118

PAWL PAWLERTH CCS_S15_M06_15PAWL_WP2_Finals_130118

KING CALLAN/KING GS CCS_S15_M06_CallanGS_WP7_Final_130522

SHEA SKEAGHACLORAN CCS_S15_M06_15SHEA_WP2_Finals_130118

KING KINGS RIVER CCS_S15_M06_15KING_WP2_Final_130731

(9) Survey Issues: (a) Annamult (15001) gauging station (254289 144376) was not initially captured by the surveyors; its location is shown in Figure 4.7.9. The gauge was later captured as part of an Infill Survey and is now included in the model.

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Figure 4.7.9: Location of Annamult gauge (15001)

(a) Callan (15009) gauging station (241551 143868) was not initially captured by the surveyors; its location is shown in Figure 4.7.10. The gauge was later captured as part of an Infill Survey and is now included in the model.

Figure 4.7.10: Location of the Callan gauge (15009)

4.7.3 Hydraulic Model Construction

(1) 1D Structures (in-channel along modelled See Appendix A.1 watercourses): Number of Bridges and Culverts: 17

Number of Weirs: 6

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Four culverts (15PAWL00052I and 15PAWL00018) were not represented in the model. Survey details or a photograph of each structure is included below.

The survey information recorded includes a photograph of each structure which has been used to determine the Manning’s n value. Further details are included in Section 3.4.1. A discussion on how the structures have been modelled is included in Section 3.3.3.

Four critical structures have been identified in the model. These are 15SHEA00434J (N76 Road bridge), 15KING00145D (Newtown Road bridge), 15KING00795D (R697 Road bridge) and 15KING00449D (Ennisnag Road bridge).

The capacity of structure 15SHEA00434J is insufficient to convey flood flows during the modelled events (10%, 1% and 0.1% AEP). This causes flow to build up upstream of the structure. This flooding affects grassland and agricultural land adjacent to the River Skeaghacloran, north of Callan. No proprties are affected.

The capacity of structures 15KING00145D, 15KING00795D and 15KING00449D is insufficient to convey flood flows during the modelled events (10%, 1% and 0.1% AEP). This causes flow to build upstream of the structures. This flooding affects grassland and agricultural land adjacent to the Kings River, no properties are affected. Photographs of the critical structures are shown in Figure 4.7.11 to Figure 4.7.14 15KING00449D Ennisnag Road bridge.

Two structures located on the Pawlerth Channel originally diverted flow underneath the N76 road bridge, this section of channel has since been blocked off/disconnected and diverted through the Pawlerth Link channel, see Figure 4.7.15 and Figure 4.7.16.

Figure 4.7.11: N76 Road bridge (15SHEA00434J)

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Figure 4.7.12 15KING01145D Newtown Road bridge

Figure 4.7.13 15KING00795D R967 Road bridge

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Figure 4.7.14 15KING00449D Ennisnag Road bridge

Figure 4.7.15: Upstream face of 15PAWL00052I Figure 4.7.16: Upstream face of 15PAWL00018

It is assumed from survey data and discussions It is assumed from survey data and discussions with locals that they are no longer connected. with locals that they are no longer connected.

Two structures were excluded from the model as they are too large to be hydraulically significant, these can be seen in Figures 4.7.17 and 4.7.18.

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Figure 4.7.17: 15CALLAN00003D Figure 4.7.18: 15KING00613D

Culvert orifice too large to be hydraulically Culvert orifice too large to be hydraulically significant. Walls of bridge were input into model. significant. Walls of bridge were input into model.

(2) 1D Structures in the 2D domain None (beyond the modelled watercourses):

(3) 2D Model structures: None

(4) Defences:

Type Watercourse Bank Model Start Model End SOP (% AEP) Chainage Chainage (approx.) (approx.)

EMBANKMENT Kings River LEFT 759.26 831.218 10%

WALL Kings River LEFT 840 890 10%

WALL Kings River RIGHT 890 942.52 10%

EMBANKMENT Kings River LEFT 870 920 10%

(5) Model Boundaries - Inflows:

Full details of the flow estimates are provided in the Hydrology Report (IBE0601Rp00110_HA15 Hydrology Report_F01 - Section 4.6 and Appendix D). The boundary conditions implemented in the model are shown below in Table 4.7.1.

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Table 4.7.1: MIKE 11 Boundary Information

A review of flows and time-to-peak of inflow hydrographs was carried out during the calibration process. Initially, flows during the 0.1% AEP event in the model were lower than the estimated peak flows. There are a number of unmodelled tributaries along the model reach and so the timings of three of the tributaries have been altered. The timing of unmodelled inflows 15_1870_2_RPS and 15_1991_3_RPS was moved forward by 24 hours, and the timing of unmodelled tributary 15_1762_5_RPS was moved forward by 12 hours. As a result, the modelled peak flows at HEP 15001_RPS at the downstream boundary of the model match the estimated flows well.

Figure 4.7.19 provides an example of the associated upstream hydrograph generated for the 0.1% AEP event in the Kings River. The upstream boundary of the Kings catchment is located at HEP 15_1733_4_RPS, the model node ID at this location is 15KING01898.

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Figure 4.7.19: Inflow upstream (HEP 15_1733_4_RPS)

(6) Model Boundaries – The downstream boundary condition is a Q-h relationship generated Downstream Conditions: based on the cross-section at the downstream extent of the model. This is located at the confluence of the Kings River (Ch 17230.54) and the Nore River. Joint probability with Model 7 (Thomastown) has not been considered. The Callan AFA is greater than 10 km upstream of the downstream boundary of the model. Therefore, backwater from Model 7 (Thomastown) is considered to have no effect on flood flows within the AFA. The Q-h boundary is to be assessed during sensitivity analysis. Refer to Section 6.2.1 of the Hydrology Report and Section 3.5.1 of this report for more details of the approach.

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Figure 4.7.20: Downstream boundary Q-h relationship

(7) Model Roughness:

(a) In-Bank (1D Domain) Minimum 'n' value: 0.035 Maximum 'n' value: 0.05

(b) MPW Out-of-Bank (1D) Minimum 'n' value: 0.030 Maximum 'n' value: 0.045

(c) MPW/HPW Out-of-Bank Minimum 'n' value: 0.045 Maximum 'n' value: 0.030

(2D) (Inverse of Manning's 'M') (Inverse of Manning's 'M')

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Figure 4.7.21: Map of 2D Roughness (Manning's n)

Figure 4.7.21 illustrates the roughness values applied within the 2D model domain. 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.

(d) Examples of In-Bank Roughness Coefficients

Callan Link – 15CALLAN00055 Callan Link b – 15CALLAN00053

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Figure 4.7.22: 15CALLAN00055 Roughness Figure 4.7.23: 15CALLAN00053 Roughness

Manning’s n = 0.038 Manning’s n = 0.04

River with shallows and meanders, noticeable River with shallows and meanders, noticeable aquatic growth aquatic growth

Kings River – 15KING01521 Pawlerth River – 15PAWL00171

Figure 4.7.24: 15KING01521 Roughness Figure 4.7.25: 15PAWL00171 Roughness

Manning’s n = 0.035 Manning’s n = 0.045

Standard natural stream or river in stable condition River or stream with rocks and stones, shallow and weedy

Skeaghacloran River – 15SHEA00520 Skeaghacloran River 15SHEA00140

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Figure 4.7.26: 15SHEA00520 Roughness Figure 4.7.27: 15SHEA00140 Roughness

Manning’s n = 0.05 Manning’s n = 0.045

River or stream with rocks and stones, shallow and River or stream with rocks and stones, shallow and weedy weedy

4.7.4 Sensitivity Analysis

Sensitivity analysis to be reported in Final Version of report, as agreed with OPW.

4.7.5 Hydraulic Model Calibration and Verification

(1) Key Historical Floods (From IBE0601Rp0010_HA15 Inception Report, unless otherwise specified):

th (a) OCT 2004 Flooding occurred in Callan on 27 October following a period of heavy rainfall. Photos were found depicting extensive flooding of roads, streets, farmland, and property in the area. A peak flood level of 24.97 mOD (Malin), and a corresponding peak flow of 129 m3/s, were recorded at Annamult Gauging Station (on King’s River, upstream of its confluence with the Nore) on 29th October as reported on the OPW hydrometric website (http://www.opw.ie/hydro). A peak level of 62.86 mOD (Malin) was recorded at Callan Gauging Station as reported on the same website; however there is no corresponding flow data available.

During the 1% AEP simulated event (shown in Figure 4.7.28); extensive flooding of roads, streets, farmland and properties is seen. Photographs taken during the 2004 event (Figure 4.7.30 to Figure 4.7.32) match the simulated 1% AEP flood extent reasonably well. The modelled peak flow at the Annamult station during the 10% AEP is 122.17 m3/s, and the peak flow during the 1% AEP is 176.086 m3/s. The modelled peak water level at the Callan gauging station is 62.98 m AOD during the 1% AEP and 92.765 m AOD during the 10% AEP event suggesting that this event was in between 10% and 1% AEP.

The Callan Flood Alleviation scheme was completed in 2012; this scheme included

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the construction of embankments and walls which protect the AFA from flooding during the 10% AEP event. See Figure 4.7.29 and flood hazard maps. Due to the change of channel and floodplain morphology in the AFA, flows and water levels in the Kings River are no longer the same as those recorded before 2012. As this event occurred pre-2012, it cannot be used to facilitate model calibration.

(b) JAN 1996 Kilkenny, Callan, Thomastown and Inistioge experienced flooding on 6th January 1996 following heavy rainfall.

In Callan, floodwater flowed through houses at Lower Bridge Street when the Kings River broke its banks. A peak flood level of 62.68 mOD (Malin) was recorded at Callan gauging station (http://www.opw.ie/hydro) while downstream of Callan, at the Annamult gauging station, the peak flow on the Kings River was 113 m3/s upstream of its confluence with the River Nore.

In the modelled 10% AEP event (Figure 4.7.29), houses at Lower Bridge Street are shown to be free from flooding (this area is now defended). During the 10% AEP event, peak flow at the Annamult gauging station is 122.173 m3/s, suggesting that this event was close to a 10% AEP event. The peak modelled water level at the Callan gauging station is 62.765 m AOD during the 10% event. However this event was pre- 2012 and cannot be used to facilitate model calibration, for details see section 4.7.5(1a).

(c) JAN 1995 The historical review indicated that a flood event occurred at Ballyragget, Kilkenny, Callan and Thomastown at the end of January 1995. The flooding followed heavy rainfall. In Callan the Kings River broke its bank. A peak flood level of 62.56 mOD (Malin) was recorded at Callan gauging station (http://www.opw.ie/hydro); while downstream of Callan, the gauging station at Annamult recorded a peak flow of 109 m3/s on the King’s River, upstream of its confluence with the River Nore.

The Kings River is shown to break its banks in Callan during all simulated events (10%, 1% and 0.1% AEP), see flood hazard maps. The modelled flow at the Annamult gauge during the 10% AEP is 122.17 m3/s. The peak modelled water level at the Callan gauging station is 62.765 m AOD during the 10% AEP event, suggesting that this particular event was close to a 10% AEP. However, this event was pre-2012 and cannot be used to facilitate model calibration, for details see section 4.7.5(1a).

(d) FEB 1990 Flooding occurred in Ballyragget, Freshford, Kilkenny, and Callan on 6th February 1990. In Callan, the Kings River broke its banks. The gauging station at Callan recorded a peak level of 62.64 mOD (Malin), while the gauging station at Annamult recorded a peak level of 24.79 mOD (Malin) and a corresponding flow of 111 m3/s on 6th February on the Kings River, upstream of its confluence with the Nore

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(http://www.opw.ie/hydro).

The King’s River is shown to break its banks in Callan during all simulated events (10%, 1% and 0.1% AEP), see flood hazard maps. The modelled peak flow at the Annamult gauge during the 10% AEP event is 122 m3/s. The recorded water level of this event at the Annamult gauging station is 24.79 mOD (Malin) which is higher than the modelled 0.1% AEP event of 24.56 mOD (Malin). The Inception Report indicated that the River Nore had high water levels which would have been the critical factor controlling water level at the Annamult gauging station. The peak modelled water level at the Callan gauging station is 62.76 mOD (Malin). Recorded flow from the Annamult gauging station, and recorded water level from the Callan gauging station, suggest that this event was close to a 10% AEP event. There is, however, uncertainty with the recorded water level at the Annamult gauging station for this event and this event was pre-2012 (see section 4.7.5(1a) for details), so cannot be used to facilitate model calibration.

(e) AUG 1986 The review of information indicated that a flood event occurred in Ballyragget, Freshford, Kilkenny and Callan on 25th August 1986 due to heavy rainfall. In Callan, the Kings river overflowed causing flooding of houses. The gauging station at Callan recorded a peak level of 62.68 mOD (Malin), while the gauging station at Annamult recorded a peak level of 24.92 mOD (Malin) and a corresponding flow of 124 m3/s on 26th August on the Kings River upstream of its confluence with the Nore (http://www.opw.ie/hydro).

In the modelled 10% AEP event, houses at Lower Bridge Street are free of flooding (this area is now defended), see flood hazard maps. The recorded water level for this event at the Annamult gauge is higher than the modelled peak water level during the 0.1% AEP event (24.56 mOD). During this flood event the River Nore had high flows. This high flow was the controlling factor for water level at the Annamult gauge, which is responsible for the unusually high water level. The modelled peak water level at the Callan gauging station is 62.749 m AOD during the 10% event, suggesting that this event was close to a 10% AEP event. There is however uncertainty with the recorded water level at the Annamult gauging station for this event and this event was pre- 2012 so cannot be used to facilitate model calibration, for details see Section 4.7.5(1a).

st (f) DEC 1960 Flooding occurred in Kilkenny, Callan, Thomastown and Inistioge on 1 December 1960 caused by heavy rainfall and snowmelt. In Callan, shops and houses were flooded to a depth of two feet. The gauging station at Callan recorded a peak level of 62.99 mOD (Malin), while the gauging station at Annamult recorded a peak level of 24.82 mOD (Malin) and a corresponding flow of 110 m3/s on 26th August on the Kings

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River upstream of its confluence with the Nore (http://www.opw.ie/hydro).

In the modelled 1% AEP event, houses and shops at Lower Bridge Street are shown to be flooded, see Figure 4.7.28. During the 10% AEP event, this area is free from flooding (this area is now defended), see Figure 4.7.29. The modelled peak water level at the Callan gauging station is 62.76 mOD (Malin) during the 10% AEP event. The modelled peak flow at the Annamult gauge during the 10% AEP event is 122.17 m3/s, suggesting that this event was close to a 10% AEP event. The recorded water level at the Annamult gauging station is higher than the modelled water level during a 0.1% AEP event. During this flood event, the River Nore had a high flow which is the controlling factor for water level at the Annamult gauging station. There is uncertainty with the recorded water level at the Annamult gauging station during this event and this event was pre-2012 (see section 4.7.5(1a) for details) so cannot be used to facilitate model calibration.

th (g) OCT 1954 Flooding occurred in Kilkenny, Callan and Thomastown on 29 October 1954 caused by heavy rainfall. Flooding occurred in Callan when the Kings River broke its banks. The gauging station at Annamult recorded a peak level of 24.81 mOD (Malin), and a corresponding flow of 107 m3/s on 29th October on the Kings River upstream of its confluence with the Nore (http://www.opw.ie/hydro).

The Kings River is shown to break its banks in Callan during all simulated events (10%, 1% and 0.1% AEP), see flood hazard maps. The recorded water level at the Annamult gauge is higher than the 0.1% AEP modelled event - 24.56 mOD (Malin). During this event, the River Nore had high flows which was the controlling factor for water level at the Annamult gauging station. The modelled peak flow at the Annamult gauging station is 122.17 m3/s during the 10% AEP event, suggesting that this event was close to a 10% AEP event. There is however uncertainty with the recorded water level at the Annamult gauging station during this event and this event was pre-2012 (see Section 4.7.5(1a) for details) so cannot be used to facilitate model calibration.

th (h) MAR 1947 A major flood event was found to have occurred on 14 March 1947 in Freshford, Kilkenny, Callan, Thomastown and Inistioge. In Callan, the Kings River broke its banks, flooding 40 shops and houses on Upper and Lower Bridge Street. No information on flows or levels is available.

During the modelled 1% AEP event, houses and shops at Upper Bridge Street and Lower Bridge Street in Callan are shown to be flooded, see Figure 4.7.28: 1% AEP flood extent near Callan . During the 10% AEP event, no flooding occurs in this area (this area is now defended), see Figure 4.7.29. No flow or level data available to verify the model for this event.

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R. Sheehan

1&2 3

Figure 4.7.28: 1% AEP flood extent near Callan

Lower Bridge Street

Upper Bridge Street

Figure 4.7.29: 10% AEP flood extent at Lower Bridge Street

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Figure 4.7.30: Photograph facing upstream on the N76.

Figure 4.7.31: Photograph facing downstream on the N76.

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Figure 4.7.32: Photograph facing Kings River at the junction of Mill Lane and Minnauns Road.

Summary of Calibration There are a number of historic flood events to calibrate the model to in the AFA. Extents, levels and flows largely match well with the lower return periods (10% AEP). However, these flood events occurred before the Callan Flood Relief scheme was completed and so the modelled flood extents, flows and levels are now different. During a number of events, where flow and level data are available at the Annamult gauge, water level is skewed well above the reliable rating due to flow backing up from the River Nore. Therefore, these events cannot be used to facilitate model calibration.

A CFRAM rating review was carried out at the Callan gauging station (15009). Model parameters were adjusted to achieve best fit of the modelled rating to the highest flow spot gauging. A fair degree of agreement was achieved between the modelled rating and the observed data, for full rating review details see Section 4.7.5(a).

A mass balance check has been carried out on the model to ensure that the total volume of water entering and leaving the model at the upstream and downstream boundaries balances with the quantity of water remaining in the domain at the end of the simulation. The mass error in the 1% AEP design run was found to be -0.32%, which is within acceptable limits (Section 3.11 of this report details acceptable limits).

Model flows were validated against the estimated flows at HEP check points to ensure the model is well anchored to hydrological estimates. For example, at HEP 15001_RPS, the estimated flow during the 1% AEP event is 169.93 m3/s and the modelled flow is 176.37 m3/s. Refer to Appendix A.3 for flow tables.

There are no significant instabilities in the model results. Overall, the model is performing well and is supported by historic information.

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(2) Post Public Consultation Updates:

Following informal public consultation and formal S.I. public consultation periods in 2015, no model updates were required for Final issue.

(3) Standard of Protection of Existing Formal Defences:

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

None

(4) Gauging Stations:

There are three gauging stations on this model reach:

(a) Callan (15009)

Gauging station 15006 is located in County Kilkenny on the Kings River. Figure 4.7.33 shows the location of the gauge.

Figure 4.7.33 Callan (15006) Gauging Station Location

A national review under FSU classified Callan station as a B quality rating, meaning it is considered suitable for flows up to Qmed. Flows can be determined up to Qmed with confidence. B sites have a well defined rating up to Qmed i.e. the highest gauged flow was at least equal to or very close to Qmed, say at least 0.95 Qmed, and no significant change in channel geometry was known to occur at or about the corresponding stage.

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A rating review was carried out for this gauge. During calibration the model was adjusted to achieve best fit of the modelled rating to just above the highest flow spot gauging (1.86 m OD Malin, 23.78 m3/s). During initial calibration of the model, a lack of agreement between the modelled rating and the OPW rating in the low Q-h range was found regardless of the roughness values used. Only the upstream face cross-section of the bridge structure was surveyed and a review of the cross-sections downstream of the bridge suggests that there may be a high point in the channel, at a location downstream of the bridge, which was not captured in the survey and which controls the low stage Q-h relationship. To account for this, a cross- section was interpolated downstream of the bridge structure with the bed levels raised until agreement could be achieved with the low flow spot gaugings. This low flow control point was investigated and a cross-section was surveyed at the location, this cross-section is now included in the model in place of the interpolated section. A Manning’s n value of 0.035 on the cross-section at the gauge was required for the model to replicate the existing OPW spot gaugings. This is within range of values expected for clean, straight, natural channels.

The gauging station is located on a HPW reach, and as such the model has been constructed from surveyed cross-sections in the 1D channel of the model, and LiDAR DTM representing the 2D floodplain. Flow is accurately represented both in-channel and within the floodplain. The model produced a stable rating curve up to 108.9 m3/s (stage 2.59 m; 66.18 mOD Malin, which is an estimated 0.1% AEP flow).

The results of the rating curve are shown in Figure 4.7.34. The graph depicts the RPS modelled rating curve against the OPW rating curve. The graph shows that the model accurately represents the OPW rating curve based on the highest flow spot gaugings, to just above the highest flow spot gauging (1.86 m OD Malin, 23.78 m3/s). The model passes between the two highest flow spot gaugings and can be considered well calibrated to the spot gaugings.

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Figure 4.7.34 Comparison of Existing OPW Rating Curve, RPS Rating Curve and Spot Gaugings

(b) Annamult (15001)

This gauge is located at the downstream end of the model, just before the confluence with the River Nore. It was classified “A2” under FSU with records from 1954 to 2009 (missing 8 years from the AMAX series). 3 There is confidence in the gauge up to approximately 1.3 times Qmed (Qmed is 89.58 m /s). (c) Rathculbin (15023)

No flow or water level data is available for this gauging station and it has therefore not been used to calibrate the model.

(5) Other Information:

None

4.7.6 Hydraulic Model Assumptions, Limitations and Handover Notes

(1) Hydraulic Model Assumptions:

(a) The in-channel, structure and floodplain roughness coefficients, initially selected based on normal bounds, have been reviewed using aerial photography and survey data during the calibration process. It is considered that the selected values are representative.

(b) The time-to-peak of inflow hydrographs generated during the hydrological analysis have been reviewed during the calibration process. The timing of unmodelled inflows 15_1870_2_RPS and 15_1991_3_RPS were moved forward by 24 hours and the timing of unmodelled inflow 15_1762_5_RPS was moved forward by 12 hours. The modelled peak flows at HEP 15001_RPS at the downstream boundary of the model match the estimated flows well.

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

(d) It was assumed that 15PAWL00052I (beneath the N76) and 15PAWL00018 (beneath Lower Bridge Street) were disconnected/blocked from a review of survey data and surveyor comments. The section of watercourse between the two culverts is assumed to be dry from surveyor comments and so the section of channel and structures are not represented in the 1D model river network. This assumption was validated by the Area Engineer for Callan and subsequent defence survey.

(e) 15CALLAN00003D and 15KING00613D were not included in the model as their orifices are too large to be hydraulically significant. The soffit level of 15CALLAN00003D is 65.81 and the maximum 0.1% AEP water level is 64.891. The soffit level of 15KING00613D is 44.65 and the maximum 0.1% AEP water level is 38.293, see also Section 4.7.3.

(f) All culverts with only the upstream or downstream face surveyed had the upstream invert level raised by 0.02 m to improve model stability. This is an acceptable approach as applicable structures were of short length and this will have minimal affect on water level locally.

(g) The inflow for Pawlerth (15_1786_1_RPS) was altered from a hydrograph to constant flow value (using the peak flow as a constant) to improve model stability. This has been assessed and is an acceptable

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(h) Where only the upstream/downstream face of a structure has been surveyed, the surveyed face has been duplicated and used as the opposite face of the structure. This is assumed acceptable as all these structures were of short length and so there should be minimal difference between the upstream and downstream orifice of each structure.

(i) It should be noted that observed flooding of rural roads and outlying properties may be represented less accurately than flooding within the AFA. The MPW was modelled using cross-section data only, and the cross-sections did not contain enough data on the left and right banks. As water levels increased, the floodplain was not accurately represented as water was not able to spill as required. The majority of the cross-sections on the Kings River (From Chainage 4698.86 m to 17233 m) were extended with the use of the NDHM to provide enough information on the floodplain and to allow water to spill as necessary. Background mapping from the NDHM was applied to the MPW which allowed for more accurate floodplain representation between the 1D cross-sections. Specific areas where floodwaters were subject to glass- walling beyond the 1D cross sections were connected to the nearest cross-section to produce a more accurate mapping output. It should be noted that this method simply projects the water level from the associated cross-section onto the topography. This methodology is further discussed in Section 3; essentially it provides no attenuation for the MPW but provides improved mapping. This is reflected in the model check flows which are discussed in Appendix A.3.

(2) Hydraulic Model Limitations and Parameters:

Hydraulic Model Parameters:

MIKE 11

Timestep (seconds) 1

Wave Approximation High Order Fully Dynamic

Delta 0.85

MIKE 21

Timestep (seconds) 1

Drying / Flooding depths (metres) 0.02 / 0.03

Eddy Viscosity (and type) 0.5 (Flux Based)

MIKE FLOOD

Link Exponential Smoothing Factor Pawlerth, Ch 1029 - Ch 1232.06: 0.8

(where non-default value used) Pawlerth Link, Ch 0 – Ch 0: 0.8

Lateral Length Depth Tolerance (m) -

(where non-default value used)

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

This model is influenced by fluvial sources only. The 10%, 1% and 0.1% AEP events were simulated.

Four critical structures have been identified as causing flooding, these are 15SHEA00434J, 15KING00795D, 15KING00449D and 15KING00145D. All four structures restrict flow and cause flow to build up upstream, affecting grassland and agricultural land. No properties are affected by the critical structures, for full details see Section 4.7.3(1).

Model results show the AFA to experience flooding from the Kings River during all simulated return periods (10%, 1% and 0.1% AEP). This flooding is due to the incapacity of the Kings River channel. During all simulated return periods, flood flows exceed channel capacity at numerous locations along the Kings River. This flooding mostly inundates grassland and agricultural land, approximately 20 properties in the AFA and 20 properties downstream of the AFA are flooded during the higher return periods (1% and 0.1% AEP), see flood hazard maps. No properties are flooded during the 10% AEP event.

During the 1% AEP event, flood flows exceed channel capacity in Kings River upstream of Lower Bridge Street, overtopping the left bank and flooding approximately 10 properties on the west side of the road. The same flood mechanism occurs during the 0.1% AEP event. However, due to the higher quantity of flows, floodwaters flow east across Lower Bridge Street and inundate approximately 20 properties on Lower Bridge Street and the upstream end of Minnauns Road. Flood flows also overtop the right bank of the Kings River at the same location during the 0.1% AEP event; eight properties are flooded on the west side of Upper Bridge Street. Two commercial buildings at Westcourt Business Park are shown to experience flooding also during the 0.1% AEP event, see flood hazard maps.

Model results show the capacity of the Skeaghacloran River passing through the AFA to be adequate during all events (10%, 1% and 0.1% AEP). The only out-of-channel flow that occurs due to high flows in the Skeaghacloran River is on grassland upstream of the N76 culvert, just upstream of the AFA boundary, see flood hazard maps.

(4) Hydraulic Model Deliverables:

Please see Appendix A.4 for a list of all model files provided with this report.

(5) Quality Assurance:

Model Constructed by: Laura Howe

Model Reviewed by: Grace Glasgow

Model Approved by: Malcolm Brian

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APPENDIX A.1 MODELLED STRUCTURES

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Structure Details - Bridges and Culverts

SPRING HEIGHT FROM OPENING INVERT MANNING’S RIVER BRANCH CHAINAGE ID LENGTH SHAPE HEIGHT WIDTH (m) N (m) (m) (m) KINGS RIVER 14760 15KING00426D 1 13.4 Irregular 2.2 6.5 2.2 0.018 KINGS RIVER 14760 15KING00426D 2 13.4 Irregular 5 15.2 3.76 0.018 KINGS RIVER 14760 15KING00426D 3 13.4 Irregular 2.75 6.5 2.2 0.018 KINGS RIVER 14536 15KING00449D 1 5.74 Irregular 1.3 1.96 0.82 0.018 KINGS RIVER 14536 15KING00449D 2 5.74 Irregular 1.9 2.09 0.9 0.018 KINGS RIVER 14536 15KING00449D 3 5.74 Irregular 2.85 3.66 1.79 0.018 KINGS RIVER 14536 15KING00449D 4 5.74 Irregular 3.5 3.70 1.31 0.018 KINGS RIVER 14536 15KING00449D 5 5.74 Irregular 3.4 3.95 1.15 0.018 KINGS RIVER 14536 15KING00449D 6 5.74 Irregular 2.85 3.77 1.24 0.018 KINGS RIVER 14536 15KING00449D 7 5.74 Irregular 2.3 4.23 1.63 0.018 KINGS RIVER 14536 15KING00449D 8 5.74 Irregular 1.5 2.2 1.43 0.018 KINGS RIVER 11072 15KING00795D 1 7.75 Irregular 3.4 4.09 1.52 0.015 KINGS RIVER 11072 15KING00795D 2 7.75 Irregular 3.1 3.58 1.62 0.015 KINGS RIVER 11072 15KING00795D 3 7.75 Irregular 3.1 3.7 1.72 0.015 KINGS RIVER 11072 15KING00795D 4 7.75 Irregular 3 3.5 1.75 0.015 KINGS RIVER 11072 15KING00795D 5 7.75 Irregular 3 3.6 1.28 0.015 KINGS RIVER 11072 15KING00795D 6 7.75 Irregular 3.2 3.5 1.82 0.015 KINGS RIVER 11072 15KING00795D 7 7.75 Irregular 3 3.4 1.63 0.015 KINGS RIVER 11072 15KING00795D 8 7.75 Irregular 2.6 3.9 1.38 0.015 KINGS RIVER 7536.645 15KING001145D 1 7.3 Irregular 2.3 3.36 - 0.018 KINGS RIVER 7536.645 15KING001145D 2 7.3 Irregular 2.6 4.5 1.79 0.018 KINGS RIVER 7536.645 15KING001145D 3 7.3 Irregular 3 6.3 2.67 0.018 KINGS RIVER 7536.645 15KING001145D 4 7.3 Irregular 2.4 4.4 1.81 0.018 KINGS RIVER 2783.04 15CALLAN00048D1 3.91 Irregular 2.5 8.39 - 0.015 KINGS RIVER 947 15CALLAN00012D 1 2 Irregular 2.4 5 - 0.012 KINGS RIVER 947 15CALLAN00012D 2 2 Irregular 2.1 4.75 - 0.012 KINGS RIVER 947 15CALLAN00012D 3 2 Irregular 2.3 5.2 - 0.012 KINGS RIVER 835 15CALLAN00009D 1 8.45 Irregular 4.1 7.7 1.96 0.015 KINGS RIVER 835 15CALLAN00009D 2 8.45 Irregular 4.7 8.9 2.27 0.015 KINGS RIVER 835 15CALLAN00009D 3 8.45 Irregular 3.1 8 2.01 0.015 Skeaghacloran 3229.377 15SHEA00190D 3.5 Irregular 1.75 1.6 - 0.015 Skeaghacloran 1858.13 15SHEA00351D 3 Irregular 1.25 1.99 - 0.021 Skeaghacloran 986.58 15SHEA00428D 10.4 Irregular 1.2 2.9 - 0.021 Skeaghacloran 850 15SHEA00434J 1 135 Circle 0.73 N/A - 0.018 Skeaghacloran 850 15SHEA00434J 2 135 Circle 0.68 N/A - 0.018 Pawlerth 470 15PAWL00136J 170 Circle 1.05 N/A - 0.015 Pawlerth 875.6 15PAWL00102E 4.5 Irregular 1 1.48 - 0.021 Pawlerth 294 15PAWL00161D 4.7 Circle 0.6 N/A - 0.014 KINGS RIVER 14760 15KING00426D 4 13.4 Irregular 3.5 6.6 2.6 0.018

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SPRING HEIGHT FROM OPENING INVERT MANNING’S RIVER BRANCH CHAINAGE ID LENGTH SHAPE HEIGHT WIDTH (m) N CALLAN LINK 308 15KING00048D2 3.91 Irregular 2.5 7.6 0.022 KINGS RIVER 6023.5 15KING01297D 4.7 Irregular 2.8 12.72 - 0.022 Pawlerth 1354 15MILKB00005I 6.1 Circle 0.52 N/A - 0.015

Structure Details - Weirs RIVER BRANCH CHAINAGE ID Type KINGS RIVER 11123 15KING00786W Broad Crested KINGS RIVER 11360.5 15KING00765W Broad Crested KINGS RIVER 12979 15KING00606W Broad Crested KINGS RIVER 9238 15KING00970W Broad Crested CALLAN LINK 16.6644 15CALLAN00042W Broad Crested KINGS RIVER 14265 15KING00462W Broad Crested

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APPENDIX A.2 RIVER LONG SECTION PROFILES

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Kings River 1% AEP Peak Water Levels

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APPENDIX A.3 ESTIMATED PEAK FLOW AND MODEL FLOW COMPARISON

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IBE0600 SE CFRAM STUDY RPS PEAK WATER FLOWS

AFA Name CALLAN Model Code HA15_CALL6 Status DRAFT FINAL Date extracted from model

Peak Water Flows Check Flow Model Flow River Name & Chainage AEP (m3/s) (m3/s) Diff (%)

10% 86.90 87.48 +0.67

KINGS RIVER 965.133 1% 120.65 122.79 +1.77 15009_RPS 0.1 163.44 166.50 +1.87 % 10% 111.30 98.13 -13.21

KINGS RIVER 8802.63 1% 154.53 138.78 -11.83 15_1869_2_RPS 0.1 209.33 193.29 -10.19 % 10% 123.35 122.14 +0.98

KINGS RIVER 16741.7 1% 169.93 176.04 +3.60 15001_RPS 0.1 226.37 232.54 +2.73 % 10% 7.99 7.66 -4.11

SKEAGHACLORAN 4877.2 1% 13.43 13.43 0 15_686_5_RPS 0.1 21.73 22.83 +5.05 % 10% 0.66 8.04 +1117.42

PAWLERTH LINK 91.79 1% 1.22 8.81 +622.38 15_1786_4_RPS 0.1 % 2.17 8.95 +312.44

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The table above provides details of flow in the model at HEP inflow, check point, modelled tributary and gauging station. These flows have been compared with the hydrology flow estimation and a percentage difference provided.

The table shows that flows at the downstream extent of the River Kings (Ch 16731.9, HEP 15001_RPS) are within 5% of the estimated flow during all events, 10%, 1% and 0.1% AEP events. Demonstrating that the model is well anchored to the hydrological estimates.

Modelled peak flows in the Kings River (Ch 965.133, HEP 15009_RPS) are within 1% of the estimated peak flows during the 10% AEP return period. During the higher return period, these flows are up to 2% different than the estimated peak flows, this shows a good degree of correlation with the estimated peak flows; as such is considered well anchored to hydraulic estimate.

Modelled peak flows in the Kings River (Ch 8802.63, HEP 15_1869_2_RPS) are between 10%-13% lower when compared with the estimated peak flows during the 10%, 1% and 0.1% AEP events. This difference is due to a slightly higher degree of hydraulic attenuation than is represented through the design flow estimation.

The modelled peak flow in the Skeaghacloran River (Ch 4877.2, HEP 15_686_5_RPS) is within 5% of the estimated peak flows during the 10%, 1% and 0.1% AEP events. Demonstrating that this location is well anchored to the hydrological estimates.

The modelled peak flow in the Pawlerth Link channel (Ch 91.79, HEP 15_1786_4_RPS) is significantly higher when compared with the estimated peak flows. During all return periods (10%, 1% and 0.1% AEP) the Kings River has high water levels, which completely wash out the Pawlerth Link Channel. This results in much higher than estimated peak flows in the Pawlerth Link Channel.

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APPENDIX A.4 DELIVERABLE MODEL AND GIS FILES

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MIKE FLOOD MIKE 21 MIKE 21 RESULTS HA15_ CALL6 _MF_DES_Q10_2 HA15_CALL6_M21_DES_Q10_2 HA15_CALL6_M21_DES_2_Q10_2 HA15_ CALL6 _MF_DES_Q100_2 HA15_CALL6_M21_DES_Q100_2 HA15_CALL6_M21_DES_2_Q100_2 HA15_ CALL6 _MF_DES_Q1000_2 HA15_CALL6_M21_DES_Q1000_2 HA15_CALL6_M21_DES_2_Q1000_2 HA15_CALL6_MESH_DFS2_DES_1 HA15_CALL6_MESH_RES_DES_1

MIKE 11 - SIM FILE & RESULTS FILE MIKE 11 - NETWORK FILE MIKE 11 - CROSS-SECTION FILE MIKE 11 - BOUNDARY FILE HA15_CALL6_M11_DES_Q10_2 HA15_CALL6_NWK_DES_2 HA15_CALL6_XNS_DES_2 HA15_CALL6_BND_DES_Q10_2 HA15_CALL6_M11_ DES_Q100_2 HA15_CALL6_BND_ DES_Q100_2 HA15_CALL6_M11_ DES_Q1000_2 HA15_CALL6_BND_ DES_Q1000_2 MIKE 11 - DFS0 FILE MIKE 11 - HD FILE MIKE 11 – HD RESULTS HA15_CALL6_DFS0_Q10 HA15_CALL6_HD_DES_Q10_2 HA15_CALL6_MF_DES_Q10_2 HA15_CALL6_ DFS0_Q100 HA15_CALL6_HD_DES_Q100_2 HA15_CALL6_MF_DES_Q100_2 HA15_CALL6_ DFS0_Q1000 HA15_CALL6_HD_DES_Q1000_2 HA15_CALL6_MF_DES_Q1000_2

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GIS Deliverables – Hazard

Flood Extent Files (Shapefiles) Flood Depth Files (Raster) Water Level and Flows (Shapefiles) Fluvial Fluvial Fluvial o09exfcd001F0 o09dpfcd001F0 O09NFCDF0 o09exfcd010F0 o09dpfcd010F0 o09exfcd100F0 o09dpfcd100F0 Flood Zone Files (Shapefiles) Flood Velocity Files (Raster) Flood Defence Files (Shapefiles) Fluvial Defended Areas O09ZNA_FCDF0 o09VLfcd001F0 o09dffcd100F0 O09ZNB_FCDF0 o09VLfcd010F0 o09VLfcd100F0 Defence Failure Extent NA

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