Establishing Basic Parameters: Risk Assessment

1
Establishing Basic Parameters Risk Assessment

• Session 2
• World 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

3
Risk Assessment The Process

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

4
Risk Assessment Initial Decisions

• 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

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Step 1 Hazard Identification and Analysis

• 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

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Step 2 Vulnerability Analysis

• 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

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Step 3 Risk Analysis

• 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

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Risk Assessment Methods Approaches
Risk Assessment
Quantitative
Qualitative
Expert-driven
Community-driven

• Performed by experts
• Requires high level of technical
  expertise
• Relies on quantitative methods

• Participatory in nature
• Incorporate variations in perception and
  acceptability of risk of stakeholders
• Community-based hazard and risk mapping
• Vulnerability and capacity assessments

• 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

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Risk Assessment Techniques Risk Identification

• 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

10
Risk Assessment Techniques Risk Checklist

• 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

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Risk Assessment Techniques Risk Matrix

• 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

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Risk Assessment Techniques Risk Matrix
Ranking of multiple locations on basis of a risk
index (Location 2 has highest risk)
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
Risk Index to Community
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Risk Assessment Techniques Risk Matrix

• Ranking of multiple hazards

Very High
High
Medium
Low
Very Low
Very Low Low Medium High Very High
Forest Fires
Floods
Droughts
Epidemics
Technological
Earthquakes
FREQUENCY
SEVERITY (LOSS)
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Risk Assessment Methods Scenario Analysis

• 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

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Risk Assessment Methods Time based
Probabilistic Assessment

• 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

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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

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Monitoring Implementation

• 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

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Challenges to Risk Assessment

• 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