Global warming has led to an increase of rainfall intensities. Together with increasing urbanisation (from 54% to 60% and even 90%), the vulnerability to flash floods increases. Besides structural measures, innovative early warning systems (EWS) are needed that empower authorities, but also industries and inhabitants to become more resilient. Last decade many EWS have been executed, in order to enable institutions to become pro-active. This is a major achievement, however, these systems are often complex, enabling only few experts to work with them and a limited group of people to use them.
Royal HaskoningDHV developed together with Nelen&Schuurmans and Infoplaza an innovative smartphone app that enables inhabitants to access the needed information easily on one hand – the Flash Flood Forecasting App (FFF App). Case study for the development was Accra, the capital of Ghana, which is one of the Rockefeller 100 Resilient Cities (100RC). The development was supported by a funding for innovative solutions for African cities, Via Water.
Within Accra Metropolitan Assembly (1,6 million people) 40% lives in slums, located in flood prone areas, causing casualties each year. Warnings broadcast by radio to residents are often too late and inaccurate. Our FFF app generates, based on state-of-the-art concepts, rainfall now-casts with a resolution of 3 km. The rainfall forecast is input for a novel 3Di hydraulic model that forecasts extremely fast (within seconds) flood maps on street level.
The FFF app provides notifications when flash floods on the selected location is expected and shows the forecasted rainfall as well as the flood maps, in an interactive manner. This generic approach can be implemented worldwide. Besides the smart phone app, the system provides a sophisticated tool for urban planning, making it an excellent tool to contribute the millennium goals.