Disaster Risk Assessment
As required by the Disaster Management Amendment Act (Act No. 16 of 2015) and the National Disaster Management Framework, a disaster risk assessment must be done. This assessment will inform the disaster management plan. Not only for this but it MUST inform other planning mechanisms such as the IDP and SDF.
Conducting a disaster risk assessment
This blog will provide an introduction into conducting disaster risk assessments by and/or for municipalities and will focus on vulnerability. Various methodologies exist to conduct disaster risk assessment but the one we use is based on the Community Capitals Framework which uses 7 capitals:
- Environmental and
To calculate disaster risk these 7 capitals will be used in the following formula:
R = Disaster risk
H = Probability of a hazard with a certain magnitude
CH = Capacity of factors that impact on the magnitude of the hazard
Vhuman = Human vulnerability
Vsoc = Social vulnerability
Vcul = Cultural vulnerability
Vfin = Financial vulnerability
Vinfra = Infrastructural vulnerability
Venviro = Environmental vulnerability
Vpol = Political vulnerability
Chuman = Capacity to mitigate and limit Human vulnerability
Csoc = Capacity to mitigate and limit Social vulnerability
Ccul = Capacity to mitigate and limit Cultural vulnerability
Cfin = Capacity to mitigate and limit Capacity to deal with economic vulnerability
Cinfra = Capacity to mitigate and limit Infrastructural vulnerability
Cenviro = Capacity to mitigate and limit environmental vulnerability
Cpol = Capacity to mitigate and limit Political vulnerability
In short, the capitals can be described as follows:
- Human Capital
Human capital includes the managerial capacity and the peoples ability to withstand shocks/disasters or to adapt in time.
- Social Capital
Social capital is the quantity and quality of social resources available (e.g., networks, membership in groups (formal/informal), social relationships, and access to wider institutions in society) from which people draw.
Cultural capital considers ethnicity, generation differences, traditional beliefs and norms, stories and folklore, spirituality, habits and heritage.
Financial resources include among others savings, income, investments or businesses, and credit that people use to support their livelihoods.
Buildings and infrastructure in a community include schools, roads, water, electricity and sewer systems and access roads. including telecommunications, industrial parks, main streets, water and sewer systems, roads, etc.
The presence and status of soil, land, water, natural beauty, lakes, rivers and streams, forests, wildlife, soil, etc., in the local landscape.
Political capital as the access to power relationships, and the capacity to influence the political system and governmental processes at local and higher levels.
To use these capitals in disaster risk assessment it must be included in a model to produce disaster risk values or score. Important also is to map the vulnerability scores. GIS is therefore very important for in the assessment of disaster risk.
Various research studies developed indicators for disaster-related risk assessment of which Jordaan’s work is influential in this regard in South Africa. He developed indicators for drought risk assessment. Some of these indicators will be used in the assessment of disaster risk. The usability of indicators for this assessment will depend on the availability of data including spatial data for the use of GIS.
Vulnerability for Human Capital is a function of highest education levels, age and health. Coping is a function of perseverance and experience.
Vulnerability for Social Capital is a function of formal networks, informal support structures and safety and security nets. Coping is a function of the availability of support structures and information.
Vulnerability for Cultural Capital is a function of dependency, gender equality and beliefs and cultural beliefs. Coping is a function of innovation and experience.
Vulnerability for Financial Capital is a function of unemployment and income rate. Coping is a function of the availability of financial safety nets.
Vulnerability for Infrastructure Capital is a function of access to basic services and amenities. Coping is a function of innovation.
Vulnerability for Environmental Capital is a function of land degradation. Coping is a function of the soil quality.
Vulnerability for Political Capital is a function of availability of disaster management plans and government efficiency.
Disaster Risk Tool
The above described indicators are consolidated into a disaster risk assessment tool to calculate risk for an area. Spatial feature that will be used to map the disaster risk is municipal wards. In the tool, each ward will be assessed for its vulnerability and coping capacity (Figure below).
The end result is a ranking of wards in regards with their risk values.
Below is an example of municipal wards and the values above were linked to boundary of these wards.
A heat map was creating showing the area with the highest disaster risk.