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Towards A GIS Methodology for Disaster Risk Assessments. L. L. Lewis GISc Professional (Production). Presentation Outline. Introduction Disaster Management Cycle Scope Definitions Overview of Methodology Results and Challenges Conclusion. Introduction. - PowerPoint PPT Presentation
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L. L. LewisGISc Professional
(Production)
TOWARDS A GIS METHODOLOGY FOR DISASTER RISK ASSESSMENTS
© Western Cape Government 2013 |
Presentation Outline
2Towards a GIS Methodology for Disaster Risk Assessments
Introduction• Disaster Management Cycle• Scope • Definitions
Overview of Methodology
Results and Challenges
Conclusion
© Western Cape Government 2013 |
Introduction
3Towards a GIS Methodology for Disaster Risk Assessments
“In dealing with extreme events, many of the critical
problems that arise are inherently spatial”
(Thomas J Cova, 1999)
© Western Cape Government 2013 |
Introduction
Legislative Context
Disaster Management Act (Act 57 of 2002)• Three spheres of government• Disaster Management Plans (S 39 and 53), the prerequisite of which is a
Disaster Risk Assessment. – Department of Local Government: Disaster Risk Reduction is mandated to
facilitate and coordinate the reduction of potential risks posed by hazards in the province.
Spatial Data Infrastructure (SDI) Act (Act 54 of 2003)• Aims to establish, via the Committee for Spatial Information (CSI), standards
and procedure to promote information sharing and minimise duplication of datasets. – Reliable, up-to-date spatial data describes the current, on the ground
situation that could influence decisions relating to emergency response e.g. access to roads.
– Incorrect or outdated information could therefore directly impact on the quality of decision-making and hence on the quality of the response to disaster situations
Towards a GIS Methodology for Disaster Risk Assessments 4
© Western Cape Government 2013 |
Benefit of GIS
5Towards a GIS Methodology for Disaster Risk Assessments
© Western Cape Government 2013 |
Disaster Management Cycle
Adapted from Godschalk D R, 1991
6Towards a GIS Methodology for Disaster Risk Assessments
© Western Cape Government 2013 |
Scope
7Towards a GIS Methodology for Disaster Risk Assessments
Focus area: West Coast District MunicipalityDiscussion of GIS methodology in a disaster risk contextUse of available GIS data relevant to the disaster risk assessmentExcluding aggregated data
Aim: • Developing a GIS based methodology applicable to Disaster Risk Management• Focus on a multidisciplinary approach based on community participation and
scientific input from a broad range of experts and GIS• Increase efficiency and improve the quality of decision-making in all level of
disaster management activities.
© Western Cape Government 2013 |
Definitions
As per West Coast Disaster Risk Assessment:
8Towards a GIS Methodology for Disaster Risk Assessments
Capacity: The combination of all strengths, attributes and resources available within a community, society or organisation that can be used to achieve agreed goals.
Disaster: A progressive or sudden, widespread or localised, natural or human-caused occurrence. A serious disruption of the functioning of a community or a society involving widespread human, material, economic or environmental losses and impacts, which exceeds the ability of the affected community or society to cope using its own resources.
Hazard: A dangerous phenomenon, substance, human activity or condition that may cause loss of life, injury or other health impacts, property damage, loss of
livelihoods and services, social and economic disruption, or environmental damage.
Risk: The combination of the probability of an event and its negative consequences.
Vulnerability: The characteristics and circumstances of a community, system or asset that make it susceptible to the damaging effects of a hazard.
Overview of Methodology
© Western Cape Government 2013 |
United Nations International Strategy for Disaster Reduction
Calculating Risk
Hazard * Vulnerability
CapacityRISK =
Natural
Environmental degradation
Biological
Technological
Economic
Societal
Environmental
Technological
Access to facilities offering
shelter
Adequately trained personnel Equipment
Contingency / emergency response
plans
Hydro-meteorologic
al
Geological
© Western Cape Government 2013 |
Public Participation
Format of community based workshops:
11Towards a GIS Methodology for Disaster Risk Assessments
One workshop per local municipality
Presentation regarding purpose and context
Identification of hazards, vulnerability and capacity
Mapping exercise
Risk prioritisation process
© Western Cape Government 2013 |
GIS
Data flow process:
12Towards a GIS Methodology for Disaster Risk Assessments
Data collection (scientific data, workshops etc)
Spatialising non-spatial data (from reports and workshops)
Categorising data into hazards, vulnerability and capacity
Mapping data for the Risk Assessment document
Spatially calculating risk
© Western Cape Government 2013 |
Scientific GIS spatial assessment
13Towards a GIS Methodology for Disaster Risk Assessments
Geodatabase 1
Hazard 1 Hazard 2 Hazard 3Vulnerabilit
y 1Vulnerabilit
y 2Vulnerabilit
y 3Capacity 1 Capacity 2 Capacity 3
Risk Prioritisation
Collective Hazards
Collective Vulnerabilitie
s
Collective Capacity× ÷
Raster Conversion
Hazard 1 Hazard 2 Hazard 3Vulnerabilit
y 1Vulnerabilit
y 2Vulnerabilit
y 3Capacity 1 Capacity 2 Capacity 3
Risk
Results & Challenges
© Western Cape Government 2013 |
Collective Hazard Map
15Towards a GIS Methodology for Disaster Risk Assessments
R = H * V / C
Natural Hazards:• Geological Hazards• Hydro-meteorological HazardsEnvironmental DegradationTechnological Hazards
© Western Cape Government 2013 |
Collective Vulnerability Map
16Towards a GIS Methodology for Disaster Risk Assessments
R = H * V / C
SocietalEnvironmentalTechnologicalEconomicCritical Facility
© Western Cape Government 2013 |
Determining Capacity
17Towards a GIS Methodology for Disaster Risk Assessments
Accessibility
Network AnalysisCritical Facilities:• Schools - 5km• Health facilities - 5km• Police stations - 24km• Fire stations - 13 minutesAccess norms and standards & Population grid (CSIR)
Municipality Access No Access
Bergrivier 95.14 % 4.86 %
Cederberg 86.14 % 13.86 %
Matzikama 95.8 % 4.2 %
Saldanha Bay 98.96 % 1.04 %
Swartland 97.35 % 2.65 %
WEST COAST DM
95.86 % 4.14 %
© Western Cape Government 2013 |
Collective Capacity Map
18Towards a GIS Methodology for Disaster Risk Assessments
R = H * V / C
Access to Critical (relief) FacilitiesCritical services able to respond
© Western Cape Government 2013 |
Overall Risk Map
19Towards a GIS Methodology for Disaster Risk Assessments
R = H * V / C
Overall risk score spatially calculated
© Western Cape Government 2013 |
Public Participation & GIS Challenges
20Towards a GIS Methodology for Disaster Risk Assessments
Subjective input• Lack of understanding of context• Localised focus
Lack of expert attendance at workshops• Little / no input from local experts• Little / no representation from municipal departments
e.g. planning, environmental management etc.
Opportunist participants• Looking for work opportunities• Platform to vent (service delivery) frustrations
Lack of understanding of the bigger picture
Refinement of methods
Lack of spatial data
Aggregated data
Silos
Conclusion
© Western Cape Government 2013 |
Conclusion
22Towards a GIS Methodology for Disaster Risk Assessments
Inclusive approach
Ownership of the Risk Assessment
Mitigation strategies requires local buy-in
Potential of GIS
Improved decision-making
Thank you
Tel:Fax:
www.westerncape.gov.za
Contact Us
Lauren Lewis
Department of the Premier: Spatial Information
+27 (0)21 483 3943 +27 (0)86 519 4956