High Speed Flood Modelling to Enhance Flood Forecasts and Improve Communication of Flood Warnings (PAP014430)

Código

PAP014430

Autores

Ben Caddis, Bill Syme, Alex Minett, Simone van Schijndel

Tema

Flood forecasting and early warning systems

Resumo

The 'traditional' approach to floodplain management has been to artificially modify the passage of floodwaters through a catchment via structural means (e.g. levees or floodways) in an attempt to reduce the frequency and severity of flooding at certain locations within the catchment. Changes to floodplain management practices have seen a progressive transition from this structural approach towards a more planning and response based approach. There is increasing recognition that the traditional structural approach rarely removes the flood hazard altogether, and that floods will continue to occur across floodplains. Empowering communities to become more aware of, and resilient to, floods is now widely regarded as the most effective way to reduce the economic and social impacts of flooding. Flood forecasting and flood warning are two of the most effective flood management measures for reducing harm to the public and damage to property. In many countries throughout the world, government authorities are responsible for flood forecasting, often at a national level. Forecasts are presented to the community as a flood warning, typically with information limited to the expected peak level and time of occurrence. To most in the community, such predicted levels have little meaning and the consequences are not understood. Until now, the use of hydraulic models for flood forecasting has been limited to using simplified one-dimensional models, primarily due to computational speed and model stability. Recent advances in flood modelling software have seen the release of some two-dimensional hydraulic models that can simulate at an exceptional speed and reliability. Whilst this software has value to floodplain managers who need to model large areas (even on a country scale), the implications for flood forecasting and warning are twofold: 1. The computational speed now enables these models to be used to enhance flood forecasts; and 2. The use of two-dimensional hydraulic modelling allows the lateral flood extents and localised flood behaviour to be defined. The effect of the latter is that authorities will have the ability to provide more effective, targeted, flood warnings to the community, thus empowering the community to protect themselves and their belongings. Likewise, flood response personnel will be able to plan for and target areas where assistance is most needed. This paper includes two case studies where two-dimensional hydraulic models are used to enhance flood forecasts and have provided added value to flood warnings.