South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL South Eastern CFRAM Study HA15 Hydraulics Report Thomastown Model Client OPW Project Title South Eastern CFRAM Study Document Title IBE0601Rp0015_HA15 Hydraulics Report Model Name Thomastown Rev. Status Author(s) Modeller Reviewed by Approved By Office of Origin Issue Date D01 Draft T. Carberry L. Howe I Bentley G. Glasgow Limerick/Belfast 14/04/2014 L. Howe / L. Howe / Draft F01 K. Smart G. Glasgow Belfast 19.12.2014 Final R. R. Clements Clements L. Howe / L. Howe / Draft F02 K. Smart G. Glasgow Belfast 13/08/2015 Final R. R. Clements Clements IBE0601Rp0015 Rev F02 South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL Table of Reference Reports Relevant Report Issue Date Report Reference Section South Eastern CFRAM November Study Flood Risk IBE0601 Rp0001_Flood Risk Review_F01 3.3.13 2011 Review South Eastern CFRAM IBE0601Rp0008_HA 15 Inception Study Inception Report July 2012 4.3.2 Report_F02 UoM15 South Eastern CFRAM October IBE0601Rp0010_HA15_Hydrology Study Hydrology Report 4.7 2013 Report_F01 UoM15 South Eastern CFRAM January IBE0601Rp0016_South Eastern CFRAMS Study HA11-17 SC4 1.1 2014 Survey Contract Report_F01 Survey Contract Report 4 Hydraulic Model Details.................................................................................................................... 1 4.8 thomastown model .................................................................................................................. 1 4.8.1 General Hydraulic Model Information .................................................................................. 1 4.8.2 Hydraulic Model Schematisation ......................................................................................... 2 4.8.3 Hydraulic Model Construction ............................................................................................ 10 4.8.4 Sensitivity Analysis ............................................................................................................ 17 4.8.5 Hydraulic Model Calibration and Verification ..................................................................... 17 4.8.6 Hydraulic Model Assumptions, Limitations and Handover Notes ...................................... 32 IBE0601Rp0015 Rev F02 South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL 4 HYDRAULIC MODEL DETAILS 4.8 THOMASTOWN MODEL 4.8.1 General Hydraulic Model Information (1) Introduction: The South Eastern CFRAM Study Flood Risk Review report (IBE0601 Rp0001_Flood Risk Review_F01 ) highlighted Thomastown as an AFA for fluvial flooding based on a review of historic flooding and the extents of flood risk determined during the PFRA. Model 7 represents the Thomastown AFA and encompasses the River Nore upstream and downstream of its extent, plus associated tributaries. The total contributing area at the downstream limit of the model is 2,417km 2. A total of 72% of this comes from Model 5 upstream (Kilkenny).Both Model 6 (Callan) and Model 8 (Ballyhale) enter the River Nore at Model 7 (Thomastown). Model 6 (Callan) joins the Nore at the uppermost reach of the River Nore in Model 7 (Thomastown); whereas Model 8 (Ballyhale) joins the River Nore just upstream of the AFA in Model 7 (Thomastown). There are two gauging stations located along the length of the Thomastown model: • Mount Juliet (15011) – This gauge was not included in the FSU; • Brownsbarn (15006) – This gauge has an FSU rating of A2. Further information on these gauges is provided in Section 4.9.5. CFRAM rating reviews were carried out for both gauges in order to derive new Q med values at the stations. See Section 4.9.5(a) and (b) for full review details. Rainfall run-off (NAM) models have been developed for the contributing catchments of each gauging station in order to simulate longer AMAX series and increase confidence in the Q med . Following this process it was noted that there was significant discrepancy between simulated and gauged Q med values moving downstream. Details on how this was resolved and final Q med values is included in Section 4.4.5(e) of this report and Section 3.1 of the HA15 Hydrology Report. The simulated Q med values at each of these stations have been used to adjust FSU predicted values at each HEP within the Ballyragget model as appropriate. Qmed estimates at the various HEPs were derived using an FSU catchment descriptor-based equation, and adjusted based on the gauge at Brownsbarn or Mount Juliet as appropriate. A number of rivers have been identified as high priority watercourses within the Thomastown model, including Cloghabrody River, Jacks Stream River and a portion of the Nore River which passes through the AFA. These reaches have been modelled as 1D-2D using the MIKE suite of software. Upstream and downstream of the AFA the Nore River is designated MPW and has been modelled as 1D only. The IBE0601Rp0015 4.8-1 Rev F02 South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL Brownsbarn (15006) gauging station is located at the downstream extent of the model reach, as such the model has been extended downstream by 900m to enable calibration of this gauge. (2) Model Reference: HA15_THOM7 (3) AFAs included in the model: THOMASTOWN (4) Primary Watercourses / Water Bodies (including local names): Reach IDName NORE RIVER NORE_E NORE RIVER NORE_C&D CLOG CLOGHABRODY JACK JACKS STREAM BROW BROWNSBARN (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) 4.8.2 Hydraulic Model Schematisation (1) Map of Model Extents: Figure 4.8.1 and 4.8.2 below illustrate the extent of the modelled catchment, river centre line, HEP locations and AFA extents. The Nore catchment contains 3 Upstream Limit HEPs, 1 Downstream Limit HEP, 2 Gauging Station HEPs, 2 Intermediate HEPs and 5 Tributary HEPs. IBE0601Rp0015 4.8-2 Rev F02 South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL Figure 4.8.1Map of Model Extents IBE0601Rp0015 4.8-3 Rev F02 South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL Figure 4.8.2Map of Model extents at the AFA (2) x-y Coordinates of River (Upstream extent): Table 4.8.1Watercourses included in the model River Name x y NORE NORE C AND D 257265 140735 NORE NORE E 254185 154285 NORE NORE AT BROWNSBARN 260775 138865 CLOG CLOGHABRODY 259165 138885 JACK JACKS STREAM 259745 140735 (3) Total Modelled Watercourse Length: 22.8 (km) (4) 1D Domain only Watercourse Length: 16.5(km) (5) 1D-2D Domain 6.3(km) Watercourse Length: (6) 2D Domain Mesh Type / Resolution / Area: Rectangular / 5 metres / 7.5 (km 2) IBE0601Rp0015 4.8-4 Rev F02 South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL (7) 2D Domain Model Extent: Figure 4.8.32D Model Extent Figure 4.8.3shows the extent of the LiDAR data used in the 2D model. Buildings are illustrated in red. For details of the approach to the modelling of buildings in the 2D area, please refer to section 3.3.2 of this report. Figure 4.8.4 shows the extent of the NDHM data used. The black line shows the river network and the red boundary represents the LiDAR extent (as shown in Figure 4.8.3). A buffer zone was created between the two datasets which were smoothed together by interpolation. IBE0601Rp0015 4.8-5 Rev F02 South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL Figure 4.8.4NDMH Extent Figure 4.8.5 below shown an overview drawing of the model schematisation. Figures 4.8.6and Figure 4.8.7 show detailed views of critical structures in the model. The overview design 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 4.8.3(1) along with the location and extent of the links between the 1D and 2D models. IBE0601Rp0015 4.8-6 Rev F02 South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL Figure 4.8.5Model Schematic Overview (A – Full Extent) IBE0601Rp0015 4.8-7 Rev F02 South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL Figure 4.8.6Model Schematic Overview - Critical Structures (B – Upper MPW Section) Figure 4.8.7Model Schematic Overview - Critical Structures (C – AFA Section) IBE0601Rp0015 4.8-8 Rev F02 South Eastern CFRAM Study HA15 Hydraulics Report - DRAFT FINAL (8) Survey Information (a) Survey Folder Structure: First Level Folder Second Level Folder Third Level Folder CCS_S15_M05_07_15NORE_E 15NORE_E Data Files _WP2_Finals_131118 15NORE_E Drawings Thomastown 15NORE_E GIS CCS: Surveyor Name Photos (Naming S15: South Eastern CFRAM Study Area, convention is in the Hydrometric Area 15 format of Cross-Section M05: Model Number 5 ID and orientation - 15NORE_E: River Reference upstream, downstream, WP2 : Work Package 2 left bank or right bank) Finals: Version 131118 – Date Issued (18 th NOV 2013) (b) Survey Folder References: Reach IDName File Ref. NORE RIVER NORE_E CCS_S15_M05_07_15NORE_E _WP2_Finals_131118 NORE RIVER NORE_C&D CCS_S15_M07_15NORE _C_D_WP2_Finals_130118 CLOG CLOGHABRODY CCS_S15_M07_15CLOG_WP2_Finals_130118 JACK JACKS STREAM CCS_S15_M07_15JACK_WP2_Finals_130115 BROW BROWNSBARN CCS_S15_M07_10_Brownbarn_GS_15006_WP1_Finals_130123 (9) Survey Issues: (a) Mount Juliet 15011 gauging station (255083E 142502N) was not captured by the surveyors; its