South Eastern CFRAM Study HA 14 Hydraulics Report 4.12 Portlaoise IBE0601Rp0017 rpsgroup.com/ireland South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL South Eastern CFRAM Study HA14 Hydraulics Report Portlaoise Model DOCUMENT CONTROL SHEET Client OPW Project Title South Eastern CFRAM Study Document Title IBE0601Rp0017_HA14 Hydraulics Report_Portlaoise_F01 Model Name Portlaoise Rev Status Author(s) Modeller Reviewed by Approved By Office of Origin Issue Date M. Houston D01 Draft I. Duff I Bentley G. Glasgow Belfast Feb 2014 T. Carberry Draft F01 T. Donnelly T. Donnelly K. Smart G. Glasgow Belfast 25/03/2015 Final Draft F02 T. Donnelly T. Donnelly K. Smart G. Glasgow Belfast 13/08/2015 Final Draft F03 T. Donnelly T. Donnelly S. Patterson G. Glasgow Belfast 27/06/2016 Final IBE0601Rp0017 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL Table of Reference Reports Relevant Report Issue Date Report Reference Section South Eastern CFRAM November IBE0601 Rp0001_Flood Risk Review 3.2.5 Study Flood Risk Review 2011 South Eastern CFRAM Study Inception Report July 2012 IBE0601Rp0005_HA 14 Inception Report 4.3.2 UoM14 South Eastern CFRAM December Study Hydrology Report IBE0601Rp0011_HA14_Hydrology Report 4.6 2013 UoM14 South Eastern CFRAM January IBE0601Rp0016_South Eastern CFRAMS Study HA11-17 SC4 4 2014 Survey Contract Report Survey Contract Report 4 Hydraulic Model Details.................................................................................................................... 1 4.12 Portlaoise model ...................................................................................................................... 1 4.12.1 General Hydraulic Model Information .............................................................................. 1 4.12.2 Hydraulic Model Schematisation ..................................................................................... 2 4.12.3 Hydraulic Model Construction ........................................................................................ 11 4.12.4 Sensitivity Analysis ........................................................................................................ 30 4.12.5 Hydraulic Model Calibration and Verification ................................................................. 30 4.12.6 Hydraulic Model Assumptions, Limitations and Handover Notes .................................. 45 IBE0601Rp0017 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL 4 HYDRAULIC MODEL DETAILS 4.12 PORTLAOISE MODEL 4.12.1 General Hydraulic Model Information (1) Introduction: The South Eastern CFRAM Study Flood Risk Review report (IBE0601 Rp0001_Flood Risk Review_F01) highlighted Portlaoise as an AFA for fluvial flooding based on a review of historic flooding and the extents of flood risk determined during the PFRA. The Portlaoise model (Model 6) includes the Triogue River and a number of its tributaries as listed in Section 4.12.1(4). Portlaoise is the most upstream model of the Triogue River with the Mountmellick model located immediately downstream. The Triogue flows through Portlaoise and to the east of Mountmellick before joining the River Barrow. Its upper reaches comprise the Cush and Foyle Rivers which rise in the northern foothills of Cullenagh Mountain. In addition to the Triogue, three unnamed urban watercourses and their tributaries flow through the AFA extent. The total contributing catchment area at the downstream end of the model is approximately 84 km2 (at HEP 14_1018_1_RPS). Portlaoise hydrometric station is located within the AFA on the River Triogue (Stn no. 14014). It is relatively new with data from 2000 and was not classified under FSU. Similarly, the gauging station at Kyleclonhobert (Stn no. 14101) on the Boghlone River is relatively new with nine years of AMAX data, and was not classified under FSU. Rainfall runoff modelling was undertaken at these stations during the hydrology analysis to augment the data and provide statistical robustness to the index flow (refer to UoM 14 Hydrology Report ibe0601Rp0011, Chapter 4.6). Both stations were used as pivotal sites in adjusting Qmed estimates (based on FSU WP 2.3 and catchment descriptors) at HEPs across the model. They were also used in to anchor the model to observed data as detailed in Appendix A.3. A rating review was conducted at Station 14014 but the outputs did not warrant a change in design Qmed as discussed in Section 4.12.3 (5). The Hydrology report (IBE0601 Rp0012) contains full details of hydrology analysis for this model. The majority of the rivers in the Portlaoise model are HPW and are being modelled as 1D-2D using the MIKE suite of software. The only exceptions to this are small stretches of the Borris and Triogue River to the north of the AFA that are MPW and are being modelled in 1D only. (2) Model Reference: HA14_PLAO6 (3) AFAs included in the model: Portlaoise (4) Primary Watercourses / Water Bodies (including local names): Reach ID Name Bloomfield Stream 14BLMF Boghlone 14BOGH Boghlone Trib 14BOGT IBE0601Rp0017 4.12-1 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL Clonminam 14INAM Derry 14DERY Kylegrove 14KYLE Maryborough Drain 14MARY Peat Works 14PEAT Portlaoise 14014 River Borris 14BORS Togher 14TOGH Triogue River 14TRIO (5) Software Type (and version): (a) 1D Domain: (b) 2D Domain: (c) Other model elements: MIKE 11 (2011) MIKE 21 – Rectangular Mesh (2011) MIKE FLOOD (2011) 4.12.2 Hydraulic Model Schematisation (1) Map of Model Extents: IBE0601Rp0017 4.12-2 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL Figure 4.12.1: Map of Model Extents Figure 4.12.1 illustrates the extent of the modelled catchment, river centreline, HEP locations and AFA extents. The catchment contains 10no. Upstream Limit HEPs, 1no. Downstream Limit HEP, 3no. Intermediate HEPs and 10no. Tributary HEPs. There are two gauging station HEPSs (Stn nos. 14014 and 14101). The Station at Kyle (Stn no.14032) on the River Triogue has no useable flow or water level data and essentially serves as an Intermediate HEP in anchoring the model to hydrological estimates (Appendiz A.3). IBE0601Rp0017 4.12-3 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL (2) x-y Coordinates of River (Upstream extent): Table 4.12.1 Modelled Watercourses River Name x y 14BLMF Bloomfield Stream 249908.4 198250.3 14BOGH Boghlone 245337.9 197989.8 14BOGT Boghlone Trib 245420.3 197542.8 14INAM Clonminam 247106.1 197190.5 14DERY Derry 249312.4 196927.6 14KYLE Kylegrove 244259.1 197659.4 14MARY Maryborough Drain 248181.0 196921.4 14PEAT Peat Works 247253.5 195019.1 14014 Portlaoise 246751.5 199081.0 14BORS River Borris 249014.8 197166.3 14TOGH Togher 244966.6 196101.6 14TRIO Triogue River 247465.6 195311.4 (3) Total Modelled Watercourse Length: 40.2 km (approx.) (excluding downstream overlaps with other models) (4) 1D Domain only Watercourse Length: 1.1 km (5) 1D-2D Domain 39.1 km Watercourse Length: (6) 2D Domain Mesh Type / Resolution / Area: Rectangular / 5 metres / 65 km2 (7) 2D Domain Model Extent: Figure 4.12.2 shows the extent of the LiDAR data used in the 2D model. For details of the approach to modelling buildings in the 2D area, please refer to Section 3.3.2 of this report. IBE0601Rp0017 4.12-4 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL Modelled River Centreline AFA Boundary Figure 4.12.2: 2D Model Extent Figure 4.12.3 is an overview drawing of the model schematisation. Figure 4.12.4 to Figure 4.12.11 provide detailed views. The overview drawing 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 maps show the areas 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 4.12.3 (1) along with the location and extent of the links between the 1D and 2D models. For clarity in viewing cross-section locations, the diagrams show the full extent of the surveyed cross-sections. Note that the 1D model considers only the cross-section between the 1D-2D links. IBE0601Rp0017 4.12-5 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL Figure 4.12.3: Model Schematisation Overview Figure 4.12.4: Detail of 1D Model Cross Section and Structure Locations, 1 of 8 IBE0601Rp0017 4.12-6 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL Figure 4.12.5: Detail of 1D Model Cross Section and Structure Locations, 2 of 8 Figure 4.12.6: Detail of 1D Model Cross Section and Structure Locations, 3 of 8 IBE0601Rp0017 4.12-7 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL Figure 4.12.7: Detail of 1D Model Cross Section and Structure Locations, 4 of 8 Figure 4.12.8: Detail of 1D Model Cross Section and Structure Locations 5 of 8 IBE0601Rp0017 4.12-8 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL Figure 4.12.9: Detail of 1D Model Cross Section and Structure Locations 6 of 8 Figure 4.12.10: Detail of 1D Model Cross Section and Structure Locations 7 of 8 IBE0601Rp0017 4.12-9 Rev F03 South Eastern CFRAM Study HA14 Hydraulics Report - DRAFT FINAL Figure 4.12.11: Detail of 1D Model Cross Section and Structure Locations 8 of 8 (8) Survey Information (a) Survey Folder Structure: First Level Folder Second Level Folder Third Level Folder CCS_S14_M06_14BLMF_WP4_Final_130 Data