Appendix A.2 River Long Section Profiles
Total Page:16
File Type:pdf, Size:1020Kb
South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL South Eastern CFRAM Study HA14 Hydraulics Report Daingean Model DOCUMENT CONTROL SHEET Client OPW Project Title South Eastern CFRAM Study Document Title IBE0601Rp0017_HA14 Hydraulics Report Model Name Daingean Rev Status Author(s) Modeller Reviewed by Approved By Office of Origin Issue Date . D01 Draft Various I. Duff I Bentley G., Glasgow Belfast 05/02/2014 D02 Draft Various J. Murdy M Brian G. Glasgow Belfast 25/07/2014 F01 Draft Various J. Murdy K. Smart G. Glasgow Belfast 05/03/2015 Final F02 Draft Various J. Murdy K. Smart G. Glasgow Belfast 13/08/2015 Final IBE0601Rp0017 F02 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_F01 3.6.2 Study Flood Risk Review 2011 South Eastern CFRAM IBE0601Rp0005_HA14 Inception Study Inception Report July 2012 2.3 Report_F02 UoM14 South Eastern CFRAM December IBE0601Rp0011_HA14_Hydrology Study Hydrology Report 4.1 2013 Report_F01 UoM14 South Eastern CFRAM January IBE0601Rp0016_South Eastern CFRAMS Study HA11-17 SC4 2014 Survey Contract Report_F01 Survey Contract Report IBE0601Rp0017 F02 South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL 4 HYDRAULIC MODEL DETAILS 4.5 DAINGEAN MODEL 4.5.1 General Hydraulic Model Information (1) Introduction: The South Eastern CFRAM Study Flood Risk Review report (IBE0601 Rp0001_Flood Risk Review_F01) highlighted Daingean as an AFA for fluvial flooding based on a review of historic flooding and the extents of flood risk determined during the PFRA. The Daingean model (Model 1) is comprised of several reaches that have been designated as HPW and MPW. The HPWs are located within a close proximity to the western edge of the Daingean AFA boundary and include the Ballyowen, Daingean Town Park and Kilcrow Rivers. These watercourses flow in a generally easterly direction, draining into the Ballyowen River near the western edge of the AFA boundary. The Ballyowen River continues through the Daingean AFA where it meets the Philipstown River. The HPW section of the Philipstown River generally flows along the southern and eastern edge of the AFA, and is joined by the Daingean Town Centre River and the Town River, both of which are located within the AFA. The Philipstown River continues downstream for approximately 2km until its confluence with the River Figile. The separately modelled River Slate (Rathangan Model 2) also enters the River Figile a further 11.5km (approx.) downstream. The River Figile continues to flow until its confluence with the Black River. Approximately 34km downstream from Daingean the Black River meets the River Barrow just outside the separately modelled Monasterevin (Model 7). The contributing catchment of Model 1 is 622 km2 and it is predominantly rural (1.7% urbanised). The downstream limit of this model is at HEP 14_1820_25_RPS. The Daingean model has one gauging station located on the River Figile just downstream of its confluence with the Philipstown River (14004, Clonbulloge). This station has been listed for Rating Review, the results of this exercise are summarised in Section 4.5.5 (4)(b) of this report. The Clonbulloge gauging station has an FSU classification of A1 and therefore has a reliable rating up to approximately 1.3 x Qmed which is 20.2 m3/s based on 53 years of data up to 2009. A rating review was undertaken at station 14004 as part of the Study which did not indicate any uncertainty in the rating at the Qmed value (see HA15 Hydrology Report). Two other gauging stations associated with Daingean include Clonarrow (14037) and Ardra (14017). Further details regarding gauging stations are located in Section 4.5.5 (a) and (c). The gauged Qmed value at Station 14004 was then used to adjust FSU catchment descriptor based estimates of Qmed at each HEP within Model 1 as appropriate. The HEP representing the Slate River tributary used Station 14011 as its pivotal station as it is located on the Slate River itself. Rainfall run-off models (NAM) have been developed of the contributing catchments to selected gauging IBE0601Rp0017 4.5 - 1 F02 South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL stations throughout HA14 in order to simulate longer AMAX series and increase confidence in the Qmed where required. These NAM models were calibrated against the low to mid range continuous flow traces at each gauging station where corresponding gauge-adjusted radar-based hourly rainfall sums (or gauge data with high temporal resolution) for the catchment are available. Using the adjusted radar-based rainfall sums, and observed rainfall sums from surrounding rain gauges, a continuous flow trace was simulated, generally for the period 1954 to 2010. All the rivers that have been included in this model have been modelled as 1D and 2D using MIKE11 and MIKE21. The 1D and 2D hydrodynamic models were then integrated into one modelling system using MIKE FLOOD. (2) Model Reference: HA14_DAIN1 (3) AFAs included in the model: Daingean (4) Primary Watercourses / Water Bodies (including local names): Reach ID Name 14CLON 14004 (Gauging Station reach) 14BLAC BLACK RIVER 14BOWE BALLYOWEN RIVER 14DCTR DAINGEAN TOWN CENTRE 14DPAK DAINGEAN TOWN PARK 14FIGI FIGILE 14PHIL PHILIPSTOWN 14TOWN TOWN RIVER 14KILC KILCROW (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) IBE0601Rp0017 4.5 - 2 F02 South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL 4.5.2 Hydraulic Model Schematisation (1) Map of Model Extents: Figure 4.5.1: Daingean Model Overview IBE0601Rp0017 4.5 - 3 F02 South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL Figure 4.5.2: Map of Model Extents at AFA Level Figure 4.5.1 and Figure 4.5.2 illustrate the extent of the modelled catchment, river centreline, HEP locations and AFA extents. Figure 4.5.2 shows the AFA extent. The figures illustrate that the Daingean model contains six HEP upstream limits. There are three gauging stations associated with the Daingean model - Clonarrow (14037), Ardra (14017) and Clonbulloge (14004). These are discussed in more detail in Section 4.5.5(4). There are nine point sources in the BND file relating to HEP tributaries and a total of six HEP check flow points (including the gauge 14004_RPS). (2) x-y Coordinates of River (Upstream extent): River Name x y CLON 14004 25910.3 22440.0 BLAC Black River 260973.2 216155.9 BOWE Ballyowen River 246019.2 228101.6 DCTR Daingean Town Centre 247299.3 227343.6 DPAK Daingean Town Park 246597.2 227468.3 FIGI Figile 260802.5 223625.0 PHIL Philipstown 247078.3 226348.6 TOWN Town River 247573.2 227352.9 KILC Kilcrow 246405.2 227166.2 IBE0601Rp0017 4.5 - 4 F02 South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL (3) Total Modelled Watercourse Length: 40.8 km (approx.) (4) 1D Domain only Watercourse Length: 32.5 km (5) 1D-2D Domain 8.3 km (approx.) Watercourse Length: (approx.) (6) 2D Domain Mesh Type / Resolution / Area: Rectangular / 5 metres / 56 km2 (Area set as land value) 27 km2 (7) 2D Domain Model Extent: Figure 4.5.3: 2D Model Extent Figure 4.5.3 provides an illustration of the 2D modelled extents and the general topography of the Daingean model. The AFA boundary is outlined in red with the reach centrelines illustrated in dark blue. Figure 4.5.3 also shows the 1D modelled extent that is within the 2D area. Buildings within the Daingean AFA are illustrated in black and are also represented as land value 300 m. This method allows for the provision of more realistic flood levels and overland flow routes throughout the grid. It should be noted that IBE0601Rp0017 4.5 - 5 F02 South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL this image depicts a rectangular model grid. Therefore, there will be a slight off-set between the spatial extent of the actual building and its model representation; this is discussed in greater detail in Section 3.3.2 of this report. The grey area within this grid represents the land value of 300m, - land values were applied to this 2D surface to reduce model run times. Figure 4.5.4 shows an overview of the model schematisation for Daingean, demonstrating the surveyed cross-section locations, AFA boundary, river centreline and the area covered by the 2D model domain. Figure 4.5.5 and Figure 4.5.6 show more detailed views of the areas where there is the most significant risk of flooding and include the surveyed cross-section locations, AFA boundary and river centreline. They also show the location of the critical structures, along with the location and extent of the links between the 1D and 2D models. IBE0601Rp0017 4.5 - 6 F02 South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL Figure 4.5.4: Model Schematisation IBE0601Rp0017 4.5 - 7 F02 South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL Figure 4.5.5: Model Schematisation Overview showing HPWs IBE0601Rp0017 4.5 - 8 F02 South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL Figure 4.5.6: Detailed Area of Model Schematisation showing Critical Structures* * For clarity in viewing cross-section locations, the model schematisation diagram shows the full extent of the surveyed cross- sections. Note that the 1D model considers only the cross-section between the 1D-2D links. (8) Survey Information (a) Survey Folder Structure: First Level Folder Second Level Folder Third Level Folder CCS_S14_M01_14BLAC_WP4_Final_1304 Data Files 30 Drawings Where: Daingean GIS CCS – Surveyor Name Photos (Naming S14 – South Eastern CFRAM Study Area, convention is in the Hydrometric Area 14 format of Cross-Section M01 – Model Number 1 ID and orientation - 14BLAC– River Reference upstream, downstream, WP4 – Work Package 4 left bank or right bank) Final - Version 130430 – Date Issued (30th APR 2013) IBE0601Rp0017 4.5 - 9 F02 South Eastern CFRAM Study HA14 Hydraulics Report – DRAFT FINAL (b) Survey Folder References: Reach ID Name File Ref.