1. National Centre for Risk Analysis and Options Appraisal Risk Assessment, RASP and IMPACT Ian Meadowcroft

2. National Centre for Risk Analysis and Options Appraisal Meanings of Risk Combination of likelihood and consequences of specified outcome Likelihood - usually annual probability Outcomes include flooding, damage (properties / infrastructure), effects on people, environmental harm Individual and aggregate risk Concepts / definitions / tools reviewed in SR587

3. National Centre for Risk Analysis and Options Appraisal Conceptual Model: Source - Pathway - Receptor RECEPTORS: people, property, warning effectiveness SOURCE - High river, Tide, Waves PATHWAY: Defence operations, flooding

4. National Centre for Risk Analysis and Options Appraisal

5. Risk-based decision-making New defences Maintaining and operating defence systems Flood warning Restricting development in flood and erosion prone areas Strategic planning, policy analysis

6. National Centre for Risk Analysis and Options Appraisal

7. Risk-based decisions..... What is the national / regional risk? What is the appropriate level of spending to reduce risk? Which reach / defence poses the greatest risk? Where are the maintenance priorities? What impact might climate change have? What combination of risk management most effective? What is the ‘residual risk’, how will it change?

8. National Centre for Risk Analysis and Options Appraisal RASP - Risk Assessment for Strategic Planning RASP methodology will deliver: Failure probabilities for individual defences Failure probabilities for the defence “system” Total flood risk for identified community (impact zone) An indication of the risk associated with each defence (using information on failure probability and consequences - economic or social)

9. National Centre for Risk Analysis and Options Appraisal Indicative Floodplain

10. National Centre for Risk Analysis and Options Appraisal Urban area Agricultural land

11. National Centre for Risk Analysis and Options Appraisal Estimate the probability of overtopping and breaching for each defence section Loading Condition Good Condition PoorProbability of Breach

12. National Centre for Risk Analysis and Options Appraisal Risk: Annual Average Damage in each land use zone

13. National Centre for Risk Analysis and Options Appraisal Approach to Risk Assessment Ian Meadowcroft ian.meadowcroft@environment-agency.gov.uk