FLOODS IN A CHANGING CLIMATE Risk Management

Transcription

1 FLOODS IN A CHANGING CLIMATE Risk Management Slobodan P. Simonović Professor Civil and Environmental Engineering The University of Western Ontario London, Canada

2 5 FLOODS IN A CHANGING CLIMATE Conclusions Risk management as adaptation to climate change Use of systems approach Flood risk management as a social system management problem Systems tools Probabilistic approach (Monte Carlo simulation, Evolutionary optimization, Probabilistic MO goal programming) Fuzzy set approach (Fuzzy rule-based simulation, Fuzzy linear programming, Fuzzy Compromise MO programming) An illustrative example

3 FLOODS IN A CHANGING CLIMATE 6 Outline Introduction Global change Climate change Floods in a changing climate Risk management as adaptation Systems approach An example Calgary, Canada, June 2013 Toronto, Canada, July 2013

4 INTRODUCTION 7 Global change Global change Population growth Alterations in climate Changes in land use Changes in oceans or other water resources Changes in ecological systems They are all directly related to flooding

5 INTRODUCTION 8 Global change

6 FLOOD RISK 11 Management Principle 1 Risk of flooding Uncertainties Subjective-objective risk confusion Move from risk to resilience Flood risk management Adaptation to global change

7 FLOOD RISK 12 Management Principle 2 information resources The system in focus is a social system of: Individuals Organizations Societies and Environment. Flows connecting the subsystems: Resource, and Information. Information is used to determine resource use by subsystems. Values provide meaning to information flows.

8 13 City of London Vulnerability of Municipal Infrastructure to Climate Change-Caused Flooding Risk City of London Fuzzy risk measure Risk = Hazard x Exposure x Vulnerability Two climate change scenarios Two regulatory floods (100-year and 250-year) Critical municipal infrastructure Buildings Transportation Flood protection Emergency management Water

9 14 Methodology Rainfall-runoff transformation Hydrologic Model Floodplain mapping Hydraulic Model Infrastructure Flood Risk due to Climate Change Input Climate Scenarios Weather Generator Temperature, Precipitation Risk Assessment Analysis of Change in Climate Variables Temperature, Timing, Duration, Shifts, Precipitation Infrastructure Risk Assessment due to Change in Climate Variables

10 15 Infrastructure data Buildings Transportation Roadways Bridges Critical Infrastructure Schools Hospitals and Emergency Services Barriers Dams, Dikes, Other flood control infrastructure Sewer Infrastructure Wastewater Treatment Plants Outlets Sanitary and Storm Systems

11 16 Climate modelling Rainfall-runoff transformation Hydrologic Model Floodplain mapping Hydraulic Model Infrastructure Flood Risk due to Climate Change Input Climate Scenarios Weather Generator Temperature, Precipitation Risk Assessment Analysis of Change in Climate Variables Temperature, Timing, Duration, Shifts, Precipitation Infrastructure Risk Assessment due to Change in Climate Variables

12 24 Climate modelling

13 25 Downscalling

14 26 Hydrologic modelling Rainfall-runoff transformation Hydrologic Model Floodplain mapping Hydraulic Model Infrastructure Flood Risk due to Climate Change Input Climate Scenarios Weather Generator Temperature, Precipitation Risk Assessment Analysis of Change in Climate Variables Temperature, Timing, Duration, Shifts, Precipitation Infrastructure Risk Assessment due to Change in Climate Variables

15 27 Hydrologic modelling Modification of HEC-HMS Nesting of sub-basins Medway (5 sub-basins) Stoney (6 sub-basins) Pottersburg (4 sub-basins) Dingman (16 sub-basins)

16 28 Hydrologic modelling More frequent flooding More severe floods Two hydrologic scenarios 100-year and 250-year

17 29 Hydraulic modelling Rainfall-runoff transformation Hydrologic Model Floodplain mapping Hydraulic Model Infrastructure Flood Risk due to Climate Change Input Climate Scenarios Weather Generator Temperature, Precipitation Risk Assessment Analysis of Change in Climate Variables Temperature, Timing, Duration, Shifts, Precipitation Infrastructure Risk Assessment due to Change in Climate Variables

18 30 Hydraulic modelling Input: Streamflow from hydrologic model HEC-RAS and HEC- GeoRAS Output: floodplains to represent flood extent and depth for use in risk analysis

19 31 Hydraulic modelling 100 yr 250 yr

20 32 Risk assessment Rainfall-runoff transformation Hydrologic Model Floodplain mapping Hydraulic Model Infrastructure Flood Risk due to Climate Change Input Climate Scenarios Weather Generator Temperature, Precipitation Risk Assessment Analysis of Change in Climate Variables Temperature, Timing, Duration, Shifts, Precipitation Infrastructure Risk Assessment due to Change in Climate Variables

21 33 Risk assessment Probability Risk Assessment Output Infrastructure Flood Risk Assessment due to Climate Change Consequences -Loss of Function -Loss of Equipment -Loss of Structure Risk Indices Risk Tables Risk Maps Monetary Value Risk = Probability of hazard x Σ[Monetary damage value x Consequence ]

22 34 Risk assessment Floodplain Aerial photo Infrastructure Stage-Damage Curves Identify inundated infrastructure

23 36 Risk assessment Probability - The likelihood that a particular flood event will occur in a given year CC_LB CC_UB CC_LB CC_UB 100yr RP 100yr RP 250yr RP 250yr RP

24 39 Risk assessment Probability Risk Assessment Output Infrastructure Flood Risk Assessment due to Climate Change Consequences -Loss of Function -Loss of Equipment -Loss of Structure Risk Indices Risk Tables Risk Maps Monetary Value R ke P 3 i 1 ( D ike IM ike ) R ke =risk index ; P = probability; D = monetary value; IM ike =impact multiplier k = infrastructure type; e = infrastructure element; i = impact category

25 40 Risk assessment

26 FUTURE 41 From risk to resilience

27 FLOODS IN A CHANGING CLIMATE 42 Conclusions Risk management as adaptation to climate change Use of systems approach Flood risk management as a social system management problem Systems tools Probabilistic approach (Monte Carlo simulation, Evolutionary optimization, Probabilistic MO goal programming) Fuzzy set approach (Fuzzy rule-based simulation, Fuzzy linear programming, Fuzzy Compromise MO programming) An illustrative example

28 FLOODS IN A CHANGING CLIMATE 43 Resources Standardization of climate change impact assessment process Gaur, A., and S.P. Simonovic, (2015) Discussion towards framing a uniform climate change impact analysis process, Environmental Processes Jou Downscaling King, L., A. I. McLeod and S. P. Simonovic, (2015) Improved weather generator algorithm for multisite simulation of precipitation and temperature, Jou of the American Water Resources Association Srivastav, R. and S.P. Simonovic, (2014) Multi-site, multivariate weather generator using maximum entropy bootstrap, Climate Dynamics Srivastav, R.K., A. Schardong and S.P. Simonovic, (2014) Equidistance Quantile Matching Method for Updating IDF Curves Under Climate Change, Water Resources Management: An International Jou Mandal, S., R. K. Srivastav, and S.P. Simonovic, (2016) Use of Beta Regression for Statistical Downscaling of Precipitation in the Campbell River Basin, British Columbia, Canada, Jouof Hydrology, 538: Gaur, A., and S. P. Simonovic, (2016) Extension of Physical Scaling method and its application towards downscaling climate model based near surface air temperature, International Jou of Climatology. London case study Eum, H-I., D. Sredojevic, S. P. Simonovic, (2011) Engineering Input for the Assessment of Flood Risk due to the Climate Change in the Upper Thames River Basin, ASCE Jou of Hydrologic Engineering, 16(7): Bowering, E., A. M. Peck, and S.P. Simonovic, (2013) A flood risk assessment to municipal infrastructure due to changing climate part I:Methodology,Urban Water Jou, 11(1): Peck, A., E. Bowering, and S.P. Simonovic, (2013) A flood risk assessment to municipal infrastructure due to changing climate part II: case study, Urban Water Jou, 11(7):