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South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report – DRAFT FINAL South Eastern CFRAM Study HA12 Hydraulics Report Tullow (Tullowphelim) Model DOCUMENT CONTROL SHEET Client OPW Project Title Sooth Eastern CFRAM Study Document Title IBE0601Rp0014_HA11, 12 & 13 Hydraulics Report Model Name Tullow (Tullowphelim) Rev Status Author(s) Modeller Reviewed by Approved By Office of Issue Date Origin T. Carberry Limerick/ D01 Draft M. Toraldo S. Patterson G. Glasgow 04/07/2014 M. Nixon Belfast Draft L. Howe / L. Howe / Belfast/ F01 K. Smart G. Glasgow 08/04/2015 Final R. Clements R. Clements Manchester Draft L. Howe / L. Howe / Belfast/ F02 K. Smart G. Glasgow 13/08/2015 Final R. Clements R. Clements Manchester IBE0601Rp0014 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL Table of Reference Reports Relevant Report Issue Date Report Reference Section South Eastern CFRAM Study November IBE0601 Rp0001_Flood Risk 3.1.6 Flood Risk Review 2011 Review_F01 South Eastern CFRAM Study 4.3.2 IBE0601Rp0007_HA 11, 12 and 13 Inception Report UoM11, 12 July 2012 Inception Report_F02 & 13 South Eastern CFRAM Study 4.5 February IBE0601Rp0012_HA11, 12 & Hydrology Report UoM11, 12 2014 13_Hydrology Report_F02 & 13 South Eastern CFRAM Study January IBE0601Rp0016_South Eastern HA11-17 SC4 Survey 1.2 2014 CFRAMS Survey Contract Report_F01 Contract Report 4 Hydraulic Model Details .................................................................................................................... 1 4.9 Tullow (Tullowphelim) .............................................................................................................. 1 4.9.1 General Hydraulic Model Information .................................................................................. 1 4.9.2 Hydraulic Model Schematisation ......................................................................................... 3 4.9.3 Hydraulic Model Construction ............................................................................................ 11 4.9.4 Sensitivity Analysis ............................................................................................................ 20 4.9.5 Hydraulic Model Calibration and Verification ..................................................................... 20 4.9.6 Hydraulic Model Assumptions, Limitations and Handover Notes ...................................... 32 IBE0601Rp0014 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL 4 HYDRAULIC MODEL DETAILS 4.9 TULLOW (TULLOWPHELIM) 4.9.1 General Hydraulic Model Information (1) Introduction: The South Eastern CFRAM Study Flood Risk Review report (IBE0601 Rp0001_Flood Risk Review_F01) highlighted Tullow (Tullowphelim) as an AFA for fluvial flooding based on a review of historic flooding and the extents of flood risk determined during the PFRA. Model 2 represents the Tullow AFA and encompasses the River Slaney upstream and downstream of its extent, plus associated tributaries. Modelled tributaries include the Derreen River and one of its tributaries (Coppenagh stream); and two urban tributaries of the Slaney (Tullowphelim and Mount Wolseley streams) that flow through Tullow AFA. Model 1 (Baltinglass) is located upstream of Model 2 (Tullow). Model 2 (Tullow) then drains into Model 3 (Bunclody), all of which are located on the River Slaney. The total contributing area at the downstream limit of the model is 564 km2. The Derreen River catchment 2 area is 236 km , accounting for just over 40% of the overall model. Rathvilly gauging station (Stn no. 12013) is located near the upstream limit of the model (refer to Section 4.9.2(1)). There are 28 years of available data and it has a B classification under FSU (refer to Section 4.9.5). Rainfall runoff modeling was conducted at this station during hydrological analysis (refer to HA 11, 12, 13 Hydrology Report (IBE0601 Rp0012_F02 for details) to increase the statistical robustness of the index flow. This station was subsequently used as a pivotal site for adjusting initial Qmed estimations (based on catchment descriptors and FSU WP 2.3) at HEPs along the River Slaney. Full details of hydrology estimation are in the HA 11, 12, 13 Hydrology Report. The Tullow Flood Relief Scheme was completed in 2011. It consisted of a combination of river widening and deepening, flood walls and embankments. The River Slaney is a MPW for the modelled upstream and downstream reaches. A 4 km reach of the Slaney flowing through the Tullow AFA, together with the tributary watercourses included in the AFA, have been modelled as 1D-2D using the MIKE suite of software. The 1D-2D extent has been extended to the confluence of the River Slaney and Derreen (12_531_8_RPS). Outside of this area, the River Slaney is modelled as 1D only. (2) Model Reference: HA12_TULL2 (3) AFAs included in the model: Tullow (Tullowphelim) IBE0601Rp0014 4.9 - 1 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL (4) Primary Watercourses / Water Bodies (including local names): Reach ID Name 12SLAN5 SLANEY5 12COPP COPPENAGH 12REEN DERREEN 12MTWO MOUNTWOLSELEY STREAM 12SLAN6 SLANEY6 12SLAN7 SLANEY7 03TULL SLANEY TRIBUTARY 12TULL TULLOWPHELIM 12TUPH TULLOWPHELIM STREAM (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) IBE0601Rp0014 4.9 - 2 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL 4.9.2 Hydraulic Model Schematisation (1) Map of Model Extents: Figure 4.9.1 Map of Model Extent Figure 4.9.1 illustrates the extent of the modelled catchment, river centre line, HEP locations and AFA extents. The Slaney catchment contains one Upstream Limit HEP, one Downstream Limit HEP, five Intermediate HEPs and five Tributary HEPs. The Derreen catchment contains one Upstream Limit HEP, two Trib HEPs and discharges into the Slaney catchment at 12_531_8_RPS. Tullowphelim and Mount Wolseley streams contain one Upstream Limit HEP each and both discharge into the Slaney (at 12_1830_1 and 12_1707_2_RPS respectively). Coppenagh Stream contains one Upstream Limit HEP and it discharges into the Derreen at 12_535_7_RPS. There are three gauging stations located along the River Slaney catchment but flow data is available for only one of the stations, the aforementioned Rathvilly Station (12013 – EPA), which represents also the upstream HEP of the catchment (12013_RPS). Tullow Town Bridge (12005) and Tullowbeg (12006) have no flow or water level data available and so were used as Intermediate HEPs in anchoring the model to hydrological estimates as detailed in Appendix A.3. IBE0601Rp0014 4.9 - 3 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL Figure 4.9.2 Map of model extent at the AFA IBE0601Rp0014 4.9 - 4 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL (2) x-y Coordinates of River (Upstream extent): River Name x y 12SLAN5 SLANEY5 284911 170291 12COPP COPPENAGH 286188 175233 12REEN DERREEN 287932 174044 12MTWO MOUNTWOLSELEY STREAM 286473 172431 12SLAN6 SLANEY6 284078 174798 12TULL TULLLOWPHELIM 285565 174035 12TUPH TULLOWPHELIM STREAM 285798 173228 12SLAN7 SLANEY7 289160 185359 03TULL SLANEY TRIB. 285494 168540 (3) Total Modelled Watercourse Length: 49.2 km (approx.) (4) 1D Domain only Watercourse Length: 27.4 km (5) 1D-2D Domain 21.8 km (approx.) Watercourse Length: (approx.) (6) 2D Domain Mesh Type / Resolution / Area: Square / 5 metres / 5.7 km2 (approx.) IBE0601Rp0014 4.9 - 5 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL (7) 2D Domain Model Extent: Figure 4.9.2 2D Model Extent Figure 4.9.3 shows the extent of the LiDAR data used in the 2D model. Buildings are illustrated in black. For details of the approach to the modelling of buildings in the 2D area, please refer back to Section 3.3.2 of this report. IBE0601Rp0014 4.9 - 6 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL Figure 4.9.4 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 4.9.3). A buffer zone was created between the two datasets which were smoothed together by interpolation. Figure 4.9.3 NDHM Extent IBE0601Rp0014 4.9 - 7 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL Figure 4.9.5 shows an overview drawing of the model schematisation. Figure 4.9.6 provides more 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 map shows the area where there is the most significant risk of flooding. This figure includes the surveyed cross-section locations, AFA boundary and river centreline. It also shows the location of the critical structures as discussed in Section 4.9.3 (1), along with the location and extent of the links between the 1D and 2D models. Figure 4.9.4 Model Schematic Overview - Full Extent IBE0601Rp0014 4.9 - 8 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL Figure 4.9.5 Model Schematic Overview - Critical Structures IBE0601Rp0014 4.9 - 9 F02 South Eastern CFRAM Study HA 11, 12 & 13 Hydraulics Report - DRAFT FINAL (8) Survey Information (a) Survey Folder Structure: First Level Folder Second Level Folder Third Level Folder CCS_S12_M02_12COPP_Final_WP3_130 12COPP_Data Files 321 12COPP_Drawings Tullow (Tullowphelim) 12COPP_PDF P635-12COPP-LP