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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.
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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 Towards a GIS Methodology for Disaster Risk Assessments
Introduction “In dealing with extreme events, many of the critical problems that arise are inherently spatial” (Thomas J Cova, 1999) Towards a GIS Methodology for Disaster Risk Assessments
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 • Incorrect or outdated information could therefore directly impact on the quality of decision-making and hence on the quality of the response to disaster situations Towards a GIS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
Benefit of GIS Towards a GIS Methodology for Disaster Risk Assessments
Disaster Management Cycle • Adapted from Godschalk D R, 1991 Towards a GIS Methodology for Disaster Risk Assessments
Scope • Focus area: West Coast District Municipality • Discussion of GIS methodology in a disaster risk context • Use of available GIS data relevant to the disaster risk assessment • Excluding 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. Towards a GIS Methodology for Disaster Risk Assessments
Definitions • As per West Coast Disaster Risk Assessment: • 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. Towards a GIS Methodology for Disaster Risk Assessments
United Nations International Strategy for Disaster Reduction • Calculating Risk • Hazard * Vulnerability Societal Biological Hydro-meteorological Technological Economic Natural Geological Environmental Environmental degradation RISK = Technological Capacity Contingency / emergency response plans Adequately trained personnel Equipment Access to facilities offering shelter Towards a GIS Methodology for Disaster Risk Assessments
Public Participation • Format of community based workshops: • One workshop per local municipality • Presentation regarding purpose and context • Identification of hazards, vulnerability and capacity • Mapping exercise • Risk prioritisation process Towards a GIS Methodology for Disaster Risk Assessments
GIS • Data flow process: • 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 Towards a GIS Methodology for Disaster Risk Assessments
Scientific GIS spatial assessment Geodatabase 1 Risk Prioritisation Hazard 1 Hazard 2 Hazard 3 Vulnerability 1 Vulnerability 2 Vulnerability 3 Capacity 1 Capacity 2 Capacity 3 Hazard 1 Hazard 2 Hazard 3 Vulnerability 1 Vulnerability 2 Vulnerability 3 Capacity 1 Capacity 2 Capacity 3 Raster Conversion Collective Hazards Collective Capacity Collective Vulnerabilities ÷ × Risk Towards a GIS Methodology for Disaster Risk Assessments
Collective Hazard Map • R = H * V / C • Natural Hazards: • Geological Hazards • Hydro-meteorological Hazards • Environmental Degradation • Technological Hazards Towards a GIS Methodology for Disaster Risk Assessments
Collective Vulnerability Map • R = H * V / C • Societal • Environmental • Technological • Economic • Critical Facility Towards a GIS Methodology for Disaster Risk Assessments
Determining Capacity • Accessibility • Network Analysis • Critical Facilities: • Schools - 5km • Health facilities - 5km • Police stations - 24km • Fire stations - 13 minutes • Access norms and standards & Population grid (CSIR) Towards a GIS Methodology for Disaster Risk Assessments
Collective Capacity Map • R = H * V / C • Access to Critical (relief) Facilities • Critical services able to respond Towards a GIS Methodology for Disaster Risk Assessments
Overall Risk Map • R = H * V / C • Overall risk score spatially calculated Towards a GIS Methodology for Disaster Risk Assessments
Public Participation & GIS Challenges • 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 Towards a GIS Methodology for Disaster Risk Assessments
Conclusion • Inclusive approach • Ownership of the Risk Assessment • Mitigation strategies requires local buy-in • Potential of GIS • Improved decision-making Towards a GIS Methodology for Disaster Risk Assessments
Lauren Lewis • Department of the Premier: Spatial Information • +27 (0)21 483 3943 • +27 (0)86 519 4956 • Lauren.Lewis@westerncape.gov.za