Risk Sensitive Land Use Planning 1

Establishing Basic Parameters:

Risk Assessment

Session 2World Bank Institute

2

Risk Assessment: Concepts and Definitions

Risk Probability/likelihood of loss due to one or more hazard

eventsin pre-defined geographical area

Depends on severity of hazard, vulnerability of exposed assetsand the capacity to cope with risk

Includes time dimension or frequency of occurrence of hazards

Risk Assessment Analysis of both the severity of hazard and vulnerability of

assetsin a particular location

Could include a time-dependent dimension Can be undertaken at various levels of precision Provides input to planning strategies

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Process to determine severity and spatial distribution of risk Analytical tool for disaster risk reduction Basis for land use planning interventions

Risk Assessment: The Process

Risk Assessment

Risk Assessment

Vulnerability Assessment

Vulnerability Assessment

Hazard Assessment

Hazard Assessment

Assets at Risk

Assets at Risk

Capacity AssessmentCapacity

Assessment

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Precision of data Relatively rough information sufficient for public information and

commitment building Greater levels of precision required to justify differential treatment

of land Increasing precision increases the cost of assessment

Time-related factors Recurrence interval of extreme events Current land use practices or future risks associated with

alternative land use scenarios

Depth of assessment Hazard analysis defines the spatial scale of the hazard and also

generates commitment to public policy initiatives Vulnerability analysis helps to understand the consequences of

alternativeland use configurations

Probabilistic risk analysis captures the full range of potential casualty anddamage experiences for a rational comprehensive approach

Risk Assessment: Initial Decisions

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Analysis of: Hazards that may occur in a given area The history of the hazard occurrence The hazard intensity and impact Change in exposure with respect to time Areas that would be most affected

within the city Population groups impacted the most

Quantifies severity of hazard at a given site As a point estimate, or As a time-dependent probabilistic statement

Results can be mapped to increase understanding and usage

Geographic Information Systems can be useful

Step 1: Hazard Identification and Analysis

Risk Sensitive Land Use Planning

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Quantifies the degree of susceptibility of people and assets to sustain damage under various levels of hazard

Physical vulnerability varies across a city and depends on the existingbuilding stock and site conditions

Socio-economic vulnerability depends on population distribution,socio-economic status, gender, race/ethnicity, age, nature of economy etc.

Indicates elements at risk that need land use planning interventions

Integrates capacity analysis to estimate protective and coping capabilities

Step 2: Vulnerability Analysis

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Combines parameters of hazard and vulnerability to quantify losses

Losses may include casualty, direct material losses and indirect material losses

May or may not be time-dependent

Time dependent risk assessment provides basis to determine acceptable level of risk

Can be used to determine benefit-cost for land use planning interventions

Level of precision/approximation of risk assessment depends on purpose of its use

Step 3: Risk Analysis

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Risk Assessment

Quantitative Qualitative Expert-driven Community-driven Participatory in nature

Incorporate variations in perception and acceptability of risk of stakeholders

Community-based hazard and risk mapping

Vulnerability and capacity assessments

Performed by experts

Requires high level of technical expertise

Relies on quantitative methods

Risk Assessment: Methods & Approaches

Use analytical tools

Provides technical and financial parameters for land use planning

Suitable for subjective data

that is difficult to quantify

Do not require high level of technical expertise

Can be performed by various stakeholders

Risk Sensitive Land Use Planning

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Determines hazards that may occur in area Includes description of area and its environment

Identifies and characterizes susceptible elements to the hazard Includes vulnerability and capacity of population,

institutions and critical facilities

Uses mapping tools to facilitate the process of stakeholders’ consultation and provide input to landuse planning

Risk Assessment Techniques: Risk Identification

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Best for a specific project, event or area

Best for parameters that are difficult to quantify

Helps planners follow systematic procedure for land use decisions

Risk Assessment Techniques: Risk Checklist

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Charts parameters of frequency versus severity of hazards Uses two-dimensional chart

Can be both quantitative and qualitative Interpretation must be

consistent

Used by planners to prioritize types of risks

Risk Assessment Techniques: Risk Matrix

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Location 1

Location 2

Location 3

Location 4

Severity of Hazard 3 5 4 2

Frequency of Hazard 5 3 3 1

Human Loss Potential 3 5 4 3

Economic Loss Potential 3 5 4 4

Response Capacity 3 3 3 3

Cumulative 17 21 18 13

Ris

k In

dex t

o C

om

mu

nit

y

Risk Assessment Techniques: Risk Matrix

Ranking of multiple locations on basis of a risk index (Location 2 has highest risk)

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Ranking of multiple hazards

FREQ

UEN

CY

SEVERITY (LOSS)

Very High

High

Medium

Low

Very Low

Very Low

Low Medium HighVery High

Epidemics

Forest Fires

Floods

Technological

Droughts

Earthquakes

Risk Assessment Techniques: Risk Matrix

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Calculates potential losses from a hypothetical event Provides understanding of the spatial distribution of losses

to the built environment Develops internal institutional knowledge regarding

vulnerabilitiesof infrastructure and population

Serves as effective communication tool between variousstakeholders

Steps involve: Creating an inventory of built environment, human exposure,

and economic value Analysis of potential hazards Analysis of potential damage Translation into social and economic loss

Risk Assessment Methods: Scenario Analysis

Risk Sensitive Land Use Planning

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Estimates disaster loss from multiple events and the probability of occurrence of each event in time

Analytically most sophisticated Important for planners to understand the concepts of

probabilistic assessment Forms basis for: building code regulation, micro-

zoning,benefit/cost analysis of risk reduction options

Used to establish a threshold for acceptable risk Provides spatial distribution of severity of various

hazardsat a high level of resolution

Risk Assessment Methods: Time – based Probabilistic Assessment

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Using the Results: Establishment of Basic Planning Parameters

Based on participatory approach to: Establish level of acceptable risk Establish priorities Set planning strategies and interventions

Look at options to reduce risk: Transfer or share Eliminate or avoid Accept, or retain and manage Mitigate

Continuously monitor status of risk and interaction with land use

Factor into risk assessment and land use planning process the changes in risk

Check the effectiveness of land use planning measures in reducing risk by:

Using monitoring and evaluation forms Scheduling regular monitoring activities Assigning responsible parties Submitting progress reports Using indicators and benchmarks

Monitoring Implementation

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Multiple hazards to which people are simultaneously exposed

Difficulty in aggregating vulnerability across sectors

Wide range of assets to be accounted for in measuring vulnerability and capacity

Large number of stakeholders with roles to play in shaping risk

Unequal access to technology, Inequality in the distribution of human resources, as well as hardware and inability to buy in data from private sources

Focus on built assets at risk and less on people

Difficulty of measuring human vulnerability

Rapid changes in slums and low-income settlements

Inability to include highly vulnerable populations in assessments

Difference in expert risk assessments and public perceptions of risk

Challenges to Risk Assessment