Hazard mapping, as defined by the United Nations, is the crucial process of pinpointing geographical areas and determining the extent to which specific phenomena may pose a threat to individuals, property, infrastructure and economic activities. This entails the identification and visual representation of spatial variations in hazard events or physical conditions.
The prime objective of hazard mapping is to equip residents with information regarding the potential range of damage and the measures they can take to prevent disasters. Put simply, the hazard maps assist the communities to locate, forecast and understand the hazards that may be an issue in their localities. While it may not entirely prevent a disaster, effective use of hazard mapping can significantly mitigate the impact of disasters.
A hazard map may also show evacuation sites, evacuation routes and other disaster prevention facilities. Therefore, effective use of hazard maps enables quick and accurate evacuation, avoiding areas for potential secondary disasters, hence effectively minimising the damage from disasters.
The hazard maps usually have elements such as location, likelihood of occurrence thus frequency or return period, and severity. Some specific types of hazard maps include flood hazard maps, landslide hazard maps, volcanic hazard maps, seismic hazard maps, tsunani and storm surge hazard maps.
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Flood hazard maps are meant to mitigate damages caused by floods through smooth and prompt evacuation or, indeed, prevention of flooding. The maps are published to show depth estimates and duration of flooding as a result of river overflows following the maximum possible rainfall. Such maps can also be a basis of developing and implementing a river flood prevention plan.
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A volcanic hazard map is a map of the area that may be affected by volcanic hazards. They are a source of data for studying evacuation plans during normal times. Further, the maps also provide data for disaster prevention measures which include mountain entry restrictions, evacuation and land use during the volcanic eruptions.
The geo-hazard map becomes a tool for providing residents and communities with information on the risk of sediment disasters. It is essentially developed to facilitate evacuation of residents and communities in the event of a disaster.
There are four techniques that are usually used for developing hazard maps and these include utilisation of community knowledge, digging into historical events, scientific study and inquiry and computational modelling. Use of community knowledge is key in disaster risk management as it harnesses the local community’s knowledge, hence forming the bedrock of hazard mapping. The application of tools integral to rural development approaches such as Participatory Rural Appraisal (PRA) and Rapid Rural Appraisal (RRA) prove useful in this endeavour.
For starters, PRA is the approach that aims at incorporating the knowledge and opinions of rural people in the planning and management of projects and programmes. It is a cost effective approach and cements and inculcates the community understanding of hazards and disaster risk reduction. RRA, on the other hand, is a flexible approach that tries to shorten the time it takes to get from knowing nothing about an area or a situation to deciding what development interventions might be best for that area. RRA uses key informants, careful observation and also exploits the knowledge and experience of local people. Loosely, an RRA is meant for learning by outsiders while the PRA enables local people to conduct their own analysis, and often to plan and take action.
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Besides utilising the community knowledge technique to develop hazard maps, digging into historical events is a technique that delves into historical records. The records often hold a wealth of information on past events, vital for developing hazard maps.
In conclusion, hazard mapping is an absolutely necessary tool in disaster risk management. Hazard maps provide essential information that helps people to understand the risks of natural hazards and to help mitigate disasters. Further, they indicate the extent of expected risk areas and can be combined with disaster management information such as evacuation sites and evacuation routes, among others. By delineating areas prone to hazards, it empowers communities and authorities to make informed decisions and implement measures that save lives and protect property. It is, therefore, advisable that hazard maps are readily available for effective disaster risk management.
