Kilbeggan, Co. Westmeath Unique ID: 250426 Stage 1: Desktop Review
Total Page:16
File Type:pdf, Size:1020Kb
Location: Kilbeggan, Co. Westmeath Unique ID: 250426 (from PFRA database) Initial OPW Designation APSR AFRR IRR Co-ordinates Easting: 233250 Northing: 235500 River / Catchment / Sub-catchment Type of Flooding / Flood Risk Fluvial non-tidal Fluvial tidal Coastal (identify all that apply) Stage 1: Desktop Review 1.1 Flood History River Flow Path (include review of The River Brosna flows through Kilbeggan and meanders south westerly to Floodmaps.ie) the river’s confluence with the River Shannon at Shannon Harbour. Flood Event Records Two flood records are listed in floodmaps.ie. Specific information about the events is not available; however the Area Engineers report identifies 23 areas prone to flooding in and around Kilbeggan. PFRA database comments (in italics): 1.2 Relevant information on OPW comments flooding issues from Designated APSR on the basis of predictive analysis and historical extents. OPW and LA staff Agree with APSR but make point that lots of extractions Predictive and some history - No wedges LA comments New housing estate, but outside the extent. New mixed use development at PO.Coola bridge properties – most derelict WWTW right beside river and within extent.Just off R436 – Coola Bridge could cause a hydraulic block also. Not so much of risk. River is low. If water is abstracted – River Brosna water extraction at Kirpatrick. Lough Ennell pump water out, pipe to canal. WI project / Westmeath County Council 2011 Meeting / discussion summary comments: OPW comments • The Brosna Drainage scheme runs through Kilbeggan. There are embankments upstream of Kilbeggan that provide flood protection. There is a mill race upstream of the town at Coola Bridge which floods into the river in heavy rainfall events. • There is an industrial estate which may be below the level of the embankments in the village centre on the right bank. Dun Bia development downstream of the village may be at risk of flooding. • The mill race in the centre of the village is a tourist attraction. LA comments • Westmeath County Council felt there was a significant flood risk at Kilbeggan, particularly at Coola Bridge. • A WWTP may also be at risk. Flood Risk Review Report – UoM 25 26 Kilbeggan V0_A 1 1.4 PFRA Data 1.4.1 PFRA hazard PFRA mapping available in GIS layer: Yes No mapping PFRA mapping included on FRR map: Yes No 1.4.2 Summary of Type FRI score Principal Receptors (if available) UWWTP 2.5 Arch_Regional 53.2 Arch_National 0.25 Total 808.25 1.7 Stage 1 Aspect Clearly APSR Uncertain Evaluation Flood History (1.1) X OPW / LA Information (1.2) X PFRA Evaluation (1.4) X Overall Desktop Evaluation (if any above aspect is uncertain X then overall designation is uncertain) 1.8 Proposed level of Level A Site Visit assessment for Stage 2 site visits Level B Site Visit X 2 Flood Risk Review Report – UoM 25 26 Kilbeggan V0_A Stage 2: Site Inspection Level B Assessment Date and Time of Inspection Date:14/04/11 Time: 14:00 Names of inspection team Peter Smyth (including OPW/LA staff if present) James Murray 2.3 Local The OPW maintained embankments were discussed with one local. He knowledge - on-site indicated that the embankments had not been breached in the last seven comments years, beyond which he had no knowledge of them. He also indicated that the drainage ditches have never risen significantly and do not pose a flood risk. (OPW, LA and any info volunteered by local residents during visit) 2.4 Comments on The single span road bridge in the centre of Kilbeggan is a major constriction hydraulic to flow, this is exacerbated at the mill race upstream. However, the road level constrictions is high through the town any would act as a natural barrier to flood flows, thus (bridges, etc.) and protecting properties downstream of the bridge. conveyance routes The weir arrangement (at the head of the mill race) significantly controls levels upstream on the Brosna. Parallel drainage ditches are running at approximately 1.5 m lower than the main Brosna. OPW maintain earth embankments to avoid flooding of agricultural land upstream of weir. 2.6 Defence Assets Formal and Open Channel Watercourses Informal Flood Man-made river channel Flood relief channel Canal Defence Assets Mill leat Drainage channels / back drains (include effective and ineffective Bridges and Culvert crossings assets to inform Single Arch bridge Multi-Arch bridge asset survey and Single Span bridge Multi-Span bridge potential Box culvert(s) Pipe culvert(s) Arch Culvert(s) mitigation measures) Culverted Watercourses (culvert length is greater than just a crossing) Box culvert(s) Pipe culvert(s) Arch Culvert(s) Irregular Culvert(s) Walls and Embankments Embankment(s) Raised wall(s) Retaining wall(s) Control Structures – weirs, gates, dams Fixed crest weir Adjustable weir Dam / Barrage Sluice gates Lock gates Radial gates Storage On-line storage (natural) On-line storage (artificial) Off-line storage Outfalls Flapped outfall(s) into watercourse Unflapped outfall(s) into watercourse i.e. from smaller watercourses, drains etc. into river / estuary / sea Tidal flap(s) Tidal sluice(s) i.e. from main watercourse into estuary / sea Flood Risk Review Report – UoM 25 26 Kilbeggan V0_A 3 Other Pumping Station Erosion Protection Sand Dunes Additional notes (if required): 2.8 Initial Potential Mitigation Measures Non-structural Planning and Development control measures Sustainable Urban Drainage Systems Flood forecasting / warning Change in Operating Procedures for water level control: Public awareness campaign Individual property protection Land use management Structural Strategic development management for floodplain development: measures (integration of measures into strategic development proposals) Storage: On-line Off-line Flow diversion: Flood relief channel Flood relief culvert Increase conveyance: Bridge works Channel works Floodplain Flood defences: Walls Embankments Localised works: Defence raising In-fill gaps Trash screen Maintenance works: Culvert / channel clearance Asset maintenance Relocation of properties: Improve existing defences: (describe) Other (describe): Outcomes Recommended APSR not an APSR IRR Designation Summary Comments Kilbeggan has a long history of flooding. The PFRA mapping predicts an (if required) ongoing significant flood risk with this conclusion supported by both Local Authorities and the OPW. Kilbeggan was confirmed as an APSR following a desk based assessment, with no on-site verification required. Flood Risk Review Report – UoM 25 26 Kilbeggan V0_A 4 Photo1: Coola Bridge at Kilbeggan, Photo 2: Weir downstream of Coola upstream face. Bridge. Photo 3: Mill downstream of weir. Photo 4: Bridge downstream of weir, downstream face. 5 Flood Risk Review Report – UoM 25 26 Kilbeggan V0_A 230500 231000 231500 232000 232500 233000 233500 234000 234500 235000 235500 236000 236500 Kilbeggan 238000 ± 237500 237000 Legend APSR Boundary Rail Network 236500 for CARs only Roads Historic Flooding (National Roads Authority) @@! Incidents Airport Land Water bodies mapped OPW Embankments from RADARSAT-2 * Historic Flood Data Hydrometric Gauging 236000 H G ! Stations Architectural Heritage EPA River Network ^_ UNESCO Sites !R Rail Stations Special Protection Area Special Area for N ! Nursing Homes Conservation 235500 Residential Care N Proposed National ! for the Elderly Heritage Area !E Schools National Heritage Area ] Benefiting Lands ! Ports and Harbours Flood Extents (PFRA, 2010) 235000 !O OPW Buildings 10% AEP Flood Extent !!H Health Centres (1 in 10 chance in any given year) !G Garda Stations 1% AEP Flood Extent !H Hospitals (1 in 100 chance in any 234500 given year) !F Fire Stations 0.1% AEP Flood Extent # Civil Defence (1 in 1000 chance in any ! Head Quarters given year) o ! Airports * Data Source - Service Régional de Traitement d’Image et de Télédétection (SERTIT) (acquired on the 5th of December 2009). 234000 Client 233500 Project Shannon CFRAM Study The PFRA Flood Extents shown are indicative. They have been developed using Flood Risk Review Map Title simple and cost-effective methods that are suitable for the PFRA. They should not be Kilbeggan used for local decision-making or any other purpose without verification. Drawing Status FINAL Job No. 32102500 Figure No. Revision CAR 30 Scale 1:20,000 @ A3 Jun 28, 2011 233000 Checked Review Approved Drawn AD/SF JC KK/JM IB/PS Copyright reserved 0 0.5 1 2 Includes Ordnance Survey Ireland data reproduced under OSi Licence number EN0021011. Jacobs UK Ltd Km Unauthorised reproduction infringes Ordnance Survey Ireland and Government of Ireland copyright, © Ordnance Survey Ireland, 2011. 95 Bothwell Street, Glasgow, G2 7HX.