CDERA: Mapping hazards in the Caribbean
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CTA. 2004. CDERA: Mapping hazards in the Caribbean. ICT Update Issue 20. CTA, Wageningen, The Netherlands
Permanent link to this item: http://hdl.handle.net/10568/57691
Terry Ally reports on how the Caribbean Disaster Emergency Response Agency (CDERA) is compiling a catalogue of digital hazard maps that will enable farmers to assess flood risks.
When a natural disaster such as a hurricane strikes, there is little that farmers in the Caribbean can do to prevent damage to crops, livestock and farm buildings, and to the agricultural sector as a whole. However, there are a number of ICT-based decision support tools that can help them to mitigate damage due to specific hazards such as floods due to excessive rainfall. In 2001 the Caribbean Disaster Emergency Response Agency (CDERA), based in Barbados, carried out a ´preparedness audit´, which showed that flooding was the most frequent hazard occurring in 90% of the 16 member states, only 75% of those affected had flood contingency plans in place. The audit also revealed that little use was made of flood hazard maps for community disaster planning. CDERA therefore launched two pilot projects focusing on compiling flood hazard maps for seven member states with a view to providing information for decision makers in all sectors. One project is the Caribbean Disaster Management (CADM) project, funded by the Japan International Cooperation Agency (JICA), in which Japanese experts in flood management, community disaster preparedness, and GIS mapping are working with CDERA to detail flood hazard maps. The second project, the Caribbean Hazard Mitigation Capacity Building Project (CHAMP), funded by the Canadian International Development Agency (CIDA), which is also developing detailed multi-hazard maps for four pilot countries. CHAMP and CADM have prepared the first comprehensive catalogue of hazard maps and vulnerability assessments for the CDERA states, plus Haiti, Suriname, Martinique and Puerto Rico. These maps are included in a database, which is searchable by hazard or by country, in the CDERA virtual disaster library (www.cdera.org/doccentre). CDERA realizes that this is not enough, however. One of the things revealed in the 2001 Audit, and substantiated in the hazard maps and vulnerability assessments, was that most of the flood hazard maps produced in the region show areas that have experienced floods in the past, rather than those that are prone to flooding. By combining maps showing historical flood events with rainfall data it is possible to identify patterns, and to predict return events, i.e. when such flooding will recur in the future. The flood hazard maps show inundation as a result of return events once in 100, 50, 25, 10 or 5 years. The maps therefore provide valuable information that can be used by planners and also by farmers, enabling them to make informed decisions on matters such as which crops to plant, where, and whether they should be insured. For example, if an agricultural area is prone to flooding, with a high risk of recurrence, the farmer might decide that the area would be better suited to livestock rather than to cash crops. Alternatively, after weighing the risks, he might decide that it could be used for crops because flood events that recur every 5 or 10 years would not be of a sufficient magnitude to destroy the crops. A 50-year return event, however, would be devastating and he could make preparations. The hazard maps also provide information to guide decisions on appropriate agricultural practices. The hazard maps will be built into a geographic information system (GIS) that also includes attribute data such as roads, buildings, water courses, topography, etc., that bring the spatial data to life. GIS maps thus provide valuable additional information that hazard mitigation planners can use to assess flood risk. The main priority is to plot escape routes. By coupling the GIS data with rainfall forecasts, it is possible to assess the significance of the event, where the water will come from, and the extent of the flooding. As well as being invaluable for hazard mitigation, the GIS maps can provide crucial information on which farmers can base their decisions. They can use the maps, for example, to find the nearest markets, the state of transportation routes, population density, and which areas of land are most likely to be subject to encroachment for other uses. Based on this knowledge, farmers can assess whether farming activities in a particular area are likely be viable in the long term, and so make sound investment decisions. The GIS maps fit into CDERA´s wider Comprehensive Disaster Management portfolio, which focuses on hazard mitigation in all sectors. In the past, the focus of disaster management was preparedness and response measures, mainly in urban areas. Today, the approach has broadened to include all economic sectors, all phases of a hazard, and all hazards. The concept of preparedness has also been widened to include a wealth of decision support tools such as hazard mapping that can empower stakeholders in all sectors the sectors to take meaningful and well-informed decisions. Both projects are in their third and final year. The final hazard maps will be published on the CDERA website by mid-2005. mailto:firstname.lastname@example.org Terry Ally is Public Information Specialist at CDERA, Barbados. For more information, visit a target=_new href=http://www.cdera.org www.cdera.org