Objectives of this Briefing

Transcription

1 Eastern CFRAM Study (Catchment Flood Risk Assessment & Management) Stakeholders Briefing Poddle & Camac Watercourses Overview Grace Glasgow July 2013 Burns Beach near Brighton, Western Australia RPS has won a series of awards from the Urban Development Institute of Australia - including the Water Sensitive Urban Development Category for the Brighton Estate near Perth. Objectives of this Briefing Catchment Flood Risk Assessment & Management Studies Overview Eastern CFRAM Study - current status & project tasks The Poddle & Camac Prioritised Works Draft Flood Extent Mapping & Option Assessment Key Dates Discussion 1

2 Implementation of the EU Floods Directive & SI 122 of 2010 Previous pilot projects to inform methodologies Address fluvial and coastal flooding CFRAM Studies Based on Ireland s River Basin Districts International aspect liaison with Rivers Agency NI Projects commenced in 2011/12 with Flood Risk Management Plans to be completed in 2016 CFRAM Roles & Responsibilities OPW Competent Authority CFRAM Funding and Management Reporting, Coordination, Consultation Public Bodies, local and regional authorities CFRAM Study Project Partners Progression of minor works and schemes Appropriate planning and development with respect to flood risk Maintenance where appropriate Support RPS 2

3 CFRAM Studies The main outputs of a CFRAM Study are Flood Maps and Flood Risk Management Plans containing options, responsible parties, costs and timeframes Flood Risk Management Plans are NOT: Flood Event Emergency Response Plan Exclusive programme to address all flood problems Minor Works, Parallel Schemes / Studies Solely focused on flood protection Producing detailed designs ready to build Set of works that will progress immediately Eastern CFRAM Study Area 3

4 Eastern CFRAM HA 09 (Liffey) DCC & SDCC Areas of Further Assessment Clontarf Sutton & Howth North Raheny Sutton & Baldoyle Baldonnel Lucan to Chapelizod Sandymount High Priority Watercourses Liffey Santry Poddle Camac Eastern CFRAM - Progress Preliminary Flood Risk Assessment Where is the problem? Flood hazard & risk maps What is the problem? Eastern CFRAM Flood Risk Management Objectives What do we need to achieve? Options Development What is the solution? Poddle & Camac Part VII Planning Draft FRMPs Final FRMPs Who does the solution and when? 4

5 Eastern CFRAM - Project Tasks Data collection Flood risk review (submitted to EC Commission March 2012) Surveys Hydrological analysis Hydraulic analysis Flood risk assessment Environmental assessment Consultation and engagement Development of flood management options Preparation of flood risk management plans Poddle & Camac Watercourses History of frequent and severe flooding in these heavily urbanised catchments particularly October 2011 Some previous works undertaken aiming to address flooding problems Dublin City Co and South Dublin County Co officials made a strong case to include the watercourses in the Eastern CFRAM study Public open evening in January 2012 attended by local elected representatives and residents group follow up with detailed record of flooding events and catchment walkover survey Decision taken to prioritise these areas to allow the councils to progress viable flood risk management options in advance of the overall 2015 deadline 10 5

6 Flooding - October 2011 Flooding October 2011 Surveys River Sections, Structures & Defences CFRAMS Survey Contract 2 Liffey (Hydrometric Area 09) Tender Documentation August 2011 Receipt of Data (Camac & Poddle) September 2012 Receipt of Data (ECFRAM Study) January 2013 Floodplain Surveys National survey Data receipt September 2012 Defence Asset Condition Surveys Property Surveys 6

7 Historical events Catchment boundaries Analysis of rainfall data Hydrometric data review Hydrological analysis Gauging station rating review Estimation of design flood parameters Joint probability analysis Sensitivity analysis Future changes Hydraulic analysis Infoworks ICM Poddle 12 km of main Poddle River 61 online structures Camac 20 km of main Camac River 22 km of tributaries 13 km of culverted watercourse 117 other online structures 14 7

8 Poddle & Camac Infoworks ICM Roughness coefficients Boundary conditions 15 Poddle & Camac Infoworks ICM Flexible Triangular Mesh 1m 2 100m 2 Grid 2D Domain Area 10km 2 Entire modelled reaches are HPW Full model utilises integrated 1D/2D techniques 16 8

9 Calibration, Verification and Deliverables Available information to assist calibration and verification includes Recorded Flood Extents for October 2011 event Surveyed Flood Depth Information for October 2011 event Anecdotal account of flooding from residents groups for October 2011 Gauging Station records Calibration data for various events gathered for the Greater Dublin Strategic Drainage Study (Rainfall and Flow) Deliverables Flood extent, flood zone, flood depth, flood velocity and flood hazard function mapping 50%, 20%, 10%, 5%, 2%, 1%, 0.5% and 0.1% AEP 17 Draft flood extent mapping 18 9

10 Flood risk management options Applicable measures are shortlisted Screening selects measures on technical, environmental and economic grounds Detailed multi-criteria analysis is applied to measures/combinations of measures (options) Environmental assessments are undertaken to support the mca Preferred options are consulted on and placed in flood risk management plans or, for the Camac & Poddle, progressed as projects 19 Poddle Preferred Options Flood risk management options Hard defences and sealing manholes Hard defences, sealing manholes and upstream storage Hard defences, sealing manholes and flow diversion Camac Considered Options Hard defences Hard defences and storage 20 10

11 Hard defences & sealing manholes Hard defences, sealing manholes & upstream storage 11

12 Hard defences, sealing manholes & flow diversion Flood risk management options 24 12

13 Flood risk management options 25 Flood risk management options Cross section through Flood Embankment 13

14 Flood risk management options Cross section through Flood Wall Elected Member Briefings Public Consultation Days Eastern CFRAM - Key Dates Event Camac Poddle Political Briefings Venue County Hall, Tallaght Clondalkin LA offices, SDCC City Hall Lord Edward Street DCC Date & time 27 May, 3.00pm 19 June, 3.00pm 19 June, 3.30pm Target audience Tallaght ACM, SDCC Clondalkin ACM, SDCC South Central ACM, DCC Focus Poddle Camac Camac and Poddle Event Camac Poddle Public Consultation Days Venue Perrystown Community Centre, Clondalkin Library, SDCC Dolphin s Barn Library, DCC SDCC Date & 24 June, 1.00pm to 7.30pm 25 June, 1.00pm to 7.30pm 26 June, 1.00pm to 7.30pm time 27 June, 10.00am to 4.30pm Focus Poddle Camac Camac and Poddle Maps uploaded to (2 weeks) Stakeholder Workshop - today 28 14