VULNERABILITY AND RISK ASSESSMENT FOR THE PFRA IN IRELAND

Transcription

1 WG F THEMATIC WORKSHOP FLOODS AND ECONOMICS VULNERABILITY AND RISK ASSESSMENT FOR THE PFRA IN IRELAND Mark Adamson 25 th October 2010

2 OVERVIEW OF PFRA OVERALL APPROACH Risk Assessment Historic FRA (What has happened) Predictive FRA (What could happen) Consultation Define Significant Risk Identification of APSRs Identify APSRs (Can be based on justification under any one of the approaches + FRS) Validate, Consult & Finalise

3 PREDICTIVE PFRA PROBABILITY OF A FLOOD (HAZARD) Range of Sources of Flooding 3 Event Probabilities (where possible) CONSEQUENCES Adverse Impacts for Different Receptors People, properties, objects, places and activities that could suffer harm or damage in the event of a flood

4 RECEPTORS RECEPTOR GROUPS Social Economic Environmental Cultural Heritage RECEPTOR INDICATORS Datasets Meeting Certain Requirements (National, Spatially-Identified, Classified, )

5 RECEPTORS SOCIAL COMMUNITY INFRASTRUCTURE Schools Emergency Services Hospitals, Care Homes, Health Centres Governance Buildings RISK TO PEOPLE No. Residential Properties

6 RECEPTORS ECONOMIC PROPERTIES Commerical Properties UTILITY INFRASTRUCTURE Electricity, Gas, Telecoms, Water TRANSPORT INFRASTRUCTURE Roads, Rail, Airports AGRICULTURE

7 RECEPTORS ENVIRONMENT POLLUTION SOURCES IPPC, SEVESO Sites DESIGNATED AREAS Designated Species & Habitats SPAs, SACs

8 RECEPTORS CULTURAL ARCHITECTURAL Protected Structures ARCHEOLOGICAL National Monuments UNESCO Sites MUSEUMS

9 VULNERABILITY ASSESSMENT METHOD OF ASSESSMENT Possible to Qualitatively Describe Vulnerability by Receptor Type, But: Consequences often Not Readily Measureable No direct, quantified measure of damage Difficult to reliably monetarise damages Preferable (Necessary) to have a Consistent Metric (Category / Numeric) of Risk Inter-Comparability for Areas with Mixed Risk Definition of Aggregate Significance Thresholds

10 VULNERABILITY ASSESSMENT APPROACH ADOPTED For each Receptor type / sub-type, assess: Importance (International, National, Regional, etc.) Susceptability to damage (Total Loss Negligable) Assign Vulnerability Classification by Receptor Subjective, But: Use of Standardised Tables for Definition for Vulnerability Classifications Consistency Subject to Consultation with Experts / Key Stakeholders

11 VULNERABILITY ASSESSMENT E.G., DAMAGE TO MATTERS OF VALUE PROBABLE IMPACT DEGREE OF RECEPTOR IMPORTANCE / DESIGNATION International National Regional Local Total Loss Critical Critical Extreme High Severe Degradation Critical Extreme High Moderate Moderate Damage Extreme High Moderate Low Minor Damage High Moderate Low Low No / Negligible Damage Low** Low Low Low

12 VULNERABILITY ASSESSMENT Level 4 Receptor_C Basic Classification Education Emergency Services Primary Schools Post Primary Schools Third Level Fire Stations Garda Stations Civil Defence High Vulnerability High Vulnerability High Vulnerability High Vulnerability Moderate Vulnerability Moderate Vulnerability Governance OPW / Government Buildings VARIABLE Care Homes Nursing Homes Extreme Vulnerability Hospitals Hospitals Critical Vulnerability Health Centre Health Centres Moderate Vulnerability

13 RISK ASSESSMENT RISK (HAZARD, CONSEQUENCES) Hazard Indicative Mapping for range of sources of flooding 3 Probabilities for each source Consequences Standardised Vulnerability Classifications FLOOD RISK INDEX (FRI) Consistent Metric of Risk Standard Threshold for Significance

14 RISK ASSESSMENT TABLE OF FLOOD RISK INDEX (FRI) SCORES V u l n e r a b i l i t y Vulnerability Class Vulnerability Factor Probability of Flood Event 0.1% - Low 1% - Medium 10% - High Low Moderate High Extreme Critical

15 RISK ASSESSMENT INDIVIDUAL POINT RECEPTORS Each Receptor represents a certain level of risk Properties, Power stations, airports, hospitals, etc. Calculate FRI for each Receptor Vulnerability Classification Probability of Flooding AREAS OF RISK Cumulative risk within an area Collection of houses, businesses, other receptors Sum FRI within a given area

16 RISK ASSESSMENT AREAS OF RISK Create 500m X 500m Grid Squares Calculate FRI in each Square Identify Risk Squares: FRI > 0 (i.e., any risk) Amalgamate Adjacent Risk Squares Calculate FRI in Amalgamated Area

17 RISK ASSESSMENT

18 RISK ASSESSMENT

19 RISK ASSESSMENT

20 SIGNIFICANT RISK RISK CAN BE SIGNIFICANT FOR: Individual Receptors Hospitals Power Stations International Airports UNESCO Sites Some SACs, SPAs Areas Groups of Mixed Receptors, Typically Communities (Homes, Businesses, Social / Utility Infrastructure,..)

21 SIGNIFICANT RISK THRESHOLD FOR SIGNIFICANCE Based on Flood Risk Index (FRI) Too High Focus only on very high risk areas (Dublin, Cork) Exclude areas of high risk (Ballinasloe, Bandon, etc.) Too Low Include many / all areas of risk 1000 s of APSRs Very high cost & resource implications Unrealistic expectations for Schemes (CBR, Budgets)

22 SIGNIFICANT RISK THRESHOLD FOR SIGNIFICANCE Criteria for Selection of Threshold Good correlation with Historic FRA outcomes Agreement with findings of detailed Flood Risk Assessments Good alignment with public and political perceptions of flood risk, and where action is needed (Capture all recognised hot-spots ) Provide reasonable expectation of viable measures to address the risk

23 INITIAL RESULTS

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25 SUMMARY ADOPTED METHOD Use of Consistent Metric ( Flood Risk Index ) Degree of Subjectivity, but Method is Transparent and Robust SIGNIFICANCE THRESHOLD Crtieria for Selection of Appropriate Level Cyclic Process (6-Yearly Review) PFRA OBJECTIVE: ID APSRs, NOT DETAILED FRA

26 WG F THEMATIC WORKSHOP FLOODS AND ECONOMICS VULNERABILITY AND RISK ASSESSMENT FOR THE PFRA IN IRELAND Mark Adamson 25 th October 2010