assessment of climate change induced flood risk to buildings€¦ · risk assessment hazard...

Assessment of climate change induced Assessment of climate change induced

flood risk to buildingsflood risk to buildingsCity of London case studyCity of London case study

Slobodan P. Simonovic

ICLR and the University of Western Ontario

BackgroundBackground

• City of London supported project: Assessment of

infrastructure vulnerability to climate change

• Interdisciplinary team:

– Slobodan P. Simonovic, Professor (UWO, ICLR)– Slobodan P. Simonovic, Professor (UWO, ICLR)

– Donald H. Burn, Professor (UW)

– Dan Sandink, Manager (ICLR)

– Hyung-Il Eum, PostDoctoral Fellow (UWO)

– Angela Peck, MESc candidate (UWO)

– Lisa Bowering, MESc candidate (UWO)

– Dragan Sredojevic, MESc (UWO).

May 26, 2011 2ICLR-Basement Flooding

Key MessagesKey Messages

• Urban environments and infrastructure are vulnerable to climate change

• Adaptation cost can be very high

• Adaptation = Risk management

• Comprehensive risk assessment methodology • Comprehensive risk assessment methodology is required to gather and examine available data in order to develop an understanding of the relevant climate effects and their interactions with municipal infrastructure

• Time to act is now

May 26, 2011 ICLR-Basement Flooding 3

Presentation OutlinePresentation Outline

• Methodology for the assessment of climate

change induced flood risk

– Climate modeling

– Hydrologic modeling– Hydrologic modeling

– Hydraulic modeling

– Risk assessment

• Case study – London, ON

• Conclusions


MethodologyMethodology


Risk Assessment

Hazard Analysis

Climate Modelling

Output: precipitation for four

climate scenarios

Hydrologic Modelling

Output: streamflows

Risk Index CalculationHydraulic Modelling Risk Index Calculation

Output: climate change flood

risk indices for all infrastructure

Infrastructure Ranking

Output: risk maps showing the

locations of high risk areas;

prioritized areas of high risk

Hydraulic Modelling

Output: water surface profiles

for climate scenarios



• Hazard Analysis


Risk Assessment

Hazard Analysis

Climate Modelling


climate scenarios


Output: streamflows








Hydraulic Modelling




Climate ScenariosClimate Scenarios

• Lower bound climate scenario

– The lowest extent of change

– Historical data, GCM and weather generator

• Upper bound climate scenario• Upper bound climate scenario

– The highest extent of change

– Historical data, GCM and weather generator


Choice of GCMChoice of GCM

2.5

3.0

3.5

4.0

Pmean (2050s)

0.0

0.5

1.0

1.5

2.0

2.5

CS

IRO

Mk2

b_B

11_P

R

GIS

SE

-R_B

1_P

R

GIS

SE

-R_A

2_P

R

NC

AR

CC

SM

3_A

2_P

R

NC

AR

CC

SM

3_B

1_P

R

CS

IRO

MK

3_S

RA

1B_P

R

CS

IRO

MK

3_S

RB

1_P

R

NC

AR

CC

SM

3_A

1B_P

R

CG

CM

3T47

_PR

_B1

CS

IRO

MK

3_S

RA

2_P

R

CG

CM

3T47

_PR

_A1B

NC

AR

PC

M_A

1B_P

R

CG

CM

3T47

_PR

_A2

NC

AR

PC

M_A

2_P

R

GIS

SA

OM

_B1_

PR

MIR

OC

3.2_

ME

DR

ES

_A2…

MIR

OC

3.2_

ME

DR

ES

_A1…

GIS

SA

OM

_A1B

_PR

HA

DG

EM

1_A

1B_P

R

HA

DG

EM

1_A

2_P

R

EC

HO

-G_B

1_P

R

CG

CM

3T63

_PR

_A2

MIR

OC

3.2_

ME

DR

ES

_B1…

EC

HO

-G_A

2_P

R

CG

CM

3T63

_PR

_A1B

GF

DLC

M2.

1_B

1_P

R

CG

CM

3T63

_PR

_B1

GF

DL3

0_A

21_P

R

EC

HO

-G_A

1B_P

R

Mir

oc3

.2_H

IRE

S_B

1_P

R

GF

DLC

M2.

1_A

2_P

R

HA

DC

M3_

B1_

PR

GF

DLC

M2.

1_A

1B_P

R

CC

SR

NIE

S_B

21_P

R

HA

DC

M3_

A1B

_PR

HA

DC

M3_

A2_

PR

Mir

oc3

.2_H

IRE

S_A

1B_P

R

EC

HA

M5O

M_A

1B_P

R

EC

HA

M5O

M_B

1_P

R

EC

HA

M5O

M_A

2_P

R

Pre

c (m

m)


Weather GeneratorWeather Generator


Risk Assessment

Hazard Analysis

Climate Modelling


climate scenarios


Output: streamflows








Hydraulic Modelling




Hydrologic ModellingHydrologic 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)


� Dingman (16 sub-basins)

1500

Hydrologic ModellingHydrologic Modelling

• Two hydrologic scenarios

– 100 year return period

– 250 year return period

0

300

600

900

1200

0 50 100 150 200 250

Peak Flow (m

3

/sec)

Return Periods

CC_LB

CC_UB


Risk Assessment

Hazard Analysis

Climate Modelling


climate scenarios


Output: streamflows








Hydraulic Modelling




Hydraulic Hydraulic ModellingModelling

• HEC-RAS and HEC-GeoRAS

• Input: Streamflows from Streamflows from hydrologic model

• Output: floodplains to represent flood extent and depth for use in risk analysis


Hydraulic Hydraulic ModellingModelling



• Risk Assessment


Risk Assessment Methodology Risk Assessment Methodology

Risk Indices

Consequences-Loss of Function

Flood Risk

Risk Tables

Risk Assessment

OutputProbability

Risk Indices-Loss of Function

-Loss of Equipment

-Loss of Structure

Flood Risk

Assessment due to

Climate Change

Risk Maps

Monetary Value-Loss of Function

-Loss of Equipment

-Loss of Structure

Probability of Hazard x Σ[Monetary Value x Consequence]


Buildings– City

– Commercial, industrial,

institutional, residential

– More than 120,000

Data CollectionData Collection

Stage-Damage Curves– Ministry of Natural

Resources

– Research

Economic Data– Municipal Property Assessment Corporation

– City


Spatial DataSpatial Data


Infrastructure Flood ImpactInfrastructure Flood Impact

Infrastructure Potential Flood Effects


Buildings Structure, contents, evacuation

Critical Facilities Structure, equipment/contents, delay in service, evacuation

Risk Index CalculationRisk Index Calculation

Risk Indices


Infrastructure Flood

Risk Tables

Risk Assessment

OutputProbability


-Loss of Equipment

-Loss of Structure


Risk Assessment due

to Climate Change

Risk Maps


-Loss of Equipment

-Loss of Structure




Probability - The likelihood that a particular flood event

will occur in a given year

CC_LB CC_UB CC_LB CC_UB

1:100yr 1:100yr 1:250yr 1:250yr

CC_LB CC_UB CC_LB CC_UB



Risk Indices



Risk Tables

Risk Assessment

OutputProbability


-Loss of Equipment

-Loss of Structure


Risk Assessment due

to Climate Change

Risk Maps


-Loss of Equipment

-Loss of Structure




Flood Consequence Multipliers

Loss of Function (IM1)

Loss of Equipment (IM2)

Loss of Structure (IM3)


Floodplain

Aerial photo

Risk Index Calculation Risk Index Calculation

Aerial photo

Buildings

Identify inundated

buildings


Stage-Damage Curves


Stage-Damage Curves

Single-storeySingle-storey

with basement


(after Waters Edge, 2007)


Deterministic (quantitative) and fuzzy

(qualitative) damage measures are combined

to describe loss of structure (IM3)



Risk Indices



Risk Tables

Risk Assessment

OutputProbability


-Loss of Equipment

-Loss of Structure


Risk Assessment due

to Climate Change

Risk Maps


-Loss of Equipment

-Loss of Structure




Monetary Value

The dollar value associated to a particular

building as a result of floodingbuilding as a result of flooding

D1 D2 D3



Risk Indices



Risk Tables

Risk Assessment

OutputProbability


-Loss of Equipment

-Loss of Structure


Risk Assessment due

to Climate Change

Risk Maps


-Loss of Equipment

-Loss of Structure




∑=

××=3

1

)(i

ikeikeke IMDPR

Rke = risk index

P = probability

D = monetary value

IMike = impact multiplier

k = building type

e = building element

i = impact category


Case Study Case Study –– London, ONLondon, ON


ResultsResults

Risk Indices



Risk Tables

Risk Assessment

OutputProbability


-Loss of Equipment

-Loss of Structure


Risk Assessment due

to Climate Change

Risk Maps


-Loss of Equipment

-Loss of Structure



ResultsResults

• Table and map for each of the 4 climate

scenarios + 1 for the current state:

100 CC_LB 250 CC_LB 250 UTRCA

100 CC_UB 250 CC_UB100 CC_UB 250 CC_UB

• Areas of high risk within each scenario

individually


ResultsResults

Scenario Area(km2)

Buildings Critical Facilities

100 CC_LB 22.95 1110 3

Infrastructure affected

100 CC_UB 25.79 2535 6

250 CC_LB 25.95 2517 6

250 CC_UB 27.87 2706 6

250 UTRCA 24.56 1762 3


ResultsResults

Table Layers Map

Cell DA RI

C3 0326 0.17

Reference

Cells

100 CC_LB Scenario

C3 0326 0.17

C3/C4 0550 0.28

B3/B4 0677 0.49Dissemination

Areas

Risk Index


ResultsResults100 CC_LB scenario100 CC_LB scenario

DA 0035

2nd highest risk

Broughdale dyke

DA 0092

Highest risk

Pottersburg Creek culvert

DA 0890

3rd highest risk

The Coves


ResultsResults100 CC_UB scenario100 CC_UB scenario


ResultsResults250 CC_LB scenario250 CC_LB scenario


ResultsResults250 CC_UB scenario250 CC_UB scenario


Comparison AnalysesComparison Analyses

Five analyses:

(1) Climate change impact250 UTRCA vs. 250 CC_UB

(2) CC uncertainty - comparison of 100 year climate events100 CC_LB vs. 100 CC_UB100 CC_LB vs. 100 CC_UB

(3) CC uncertainty - comparison of 250 year climate events250 CC_LB vs. 250 CC_UB

(4) Regulatory flood - comparison of lower bound scenarios100 CC_LB vs. 250 CC_LB

(5) Regulatory flood - comparison of upper bound scenarios100 CC_UB vs. 250 CC_UB



Areas of interest include:

• Cells B5/C4: Along Pottersburg Creek, north of Trafalgar to the airport

• Cell C3: Forks of Thames River• Cell C3: Forks of Thames River

• Cells E3/E4 & D4/D5: Dingman Creek


Key MessagesKey Messages

• Urban environments and infrastructure are vulnerable to climate change

• Adaptation cost can be very high

• Adaptation = Risk management

• Comprehensive risk assessment methodology is • Comprehensive risk assessment methodology is required to gather and examine available data in order to develop an understanding of the relevant climate effects and their interactions with municipal infrastructure

• Time to act is now


ResourcesResources

www.slobodansimonovic.comwww.slobodansimonovic.comwww.slobodansimonovic.comwww.slobodansimonovic.com

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