definition

Flood hazard mapping is an exercise to define those areas which are at risk of flooding under extreme conditions. As such, its primary objective is to reduce the impact of flooding through better predictive capacity. It acts as an information system to enhance our understanding and awareness of flood risk. Creation of evolutionary mapping of the extreme meteorological events and their consequences, using GIS systems so that a bank of historic data can be constituted will result in easily-readible, rapidly-accessible charts and maps which facilitate the identification of areas at risk of flooding and also helps prioritise mitigation and response efforts.
(ClimateTechWiki, Flood hazard mapping, accessed on Sept. 2016)

Co-benefits and impacts

Identification of those areas at risk of flooding will help inform emergency responses. For example, areas that are likely to require evacuation can be identified, and evacuation routes can be planned and clearly signposted so local communities are made aware in advance of an emergency. The identification of flood risk areas will also help in the location of flood shelters for evacuees. Identification of flood risk areas is likely to help in the planning of a more effective emergency response. It is essential that certain infrastructure, such as electricity supplies, sewage treatment, etc., and services, such as the emergency services, continue to function during a flood event. The creation of flood hazard maps will therefore allow planners to locate these elements in low risk areas so that they can continue to serve during an extreme event. Alternatively, flood hazard mapping may highlight a requirement to defend these elements from flooding. Flood hazard mapping will allow quantification of what is at risk of being flooded such as the number of houses or businesses. This will help identify the scale of emergency and clean-up operations. The creation of flood hazard maps should promote greater awareness of the risk of flooding. This can be beneficial in encouraging hazard zone residents to prepare for the occurrence of flooding. In order to achieve this however, local authorities must ensure that emergency procedures are established, and that information about what to do in the event of a flood is made available to the general public. Further, it keeps memories of flood events alive and informs next generations (retains historical lessons learned from historical flood events and informs future generations). By identifying buildings at flood risk, awareness raising campaigns can also be targeted at high risk properties. This may include raising awareness of emergency flood procedures and may also promote the implementation of flood-proofing measures. In the longer-term, flood hazard maps can support planning and development by identifying high risk locations and steering development away from these areas. This will help to keep future flood risk down and also encourages sustainable development. In order for this to occur, the consideration of flood hazard maps must be integrated into planning procedures. On the other hand, in itself, flood hazard mapping does not cause a reduction in flood risk, It must be integrated into other procedures, such as emergency response planning and town planning, before the full benefits can be realised. More advanced, accurate flood hazard maps are likely to rely on complex numerical models due to the lack of observed extreme event data. This requires a degree of expertise to implement. The collection of topographic and bathymetric data to complement extreme water level and wave height information could also be expensive to collect.
(ClimateTechWiki, Flood hazard mapping, accessed on Sept. 2016)

conditions

To realise the full benefits of flood hazard mapping, it is important to provide people in the hazard zone with information about emergency procedures and ways of reducing flood risk. If information on what to do in the event of an emergency is not provided, flood hazard maps may serve only to increase fear and anxiety as residents are more aware of the risk of flooding.
(ClimateTechWiki, Flood hazard mapping, accessed on Sept. 2016)

Related Links

---

Last modified: Sept. 21, 2016, 8:36 a.m.