Using multi-temporal remote-sensing data to estimate 2011 flood area and volume over Chao Phraya River basin, Thailand

In 2011, when Thailand faced its most severe flood disaster in 50 years, the Geo-Informatics and Space Technology Development Agency provided flood affected data to support government agencies during the crisis, specifically synthetic aperture radar (SAR) imagery, optical satellite imagery and a digital elevation model (DEM). These data were combined with water level data from gauge stations to map the area flooded and to estimate water volume in near real time to support decision-making for flood relief operations. However, difficulties were encountered when dealing with different kinds of spatial data and different application techniques. Problems included inconsistent acquisition schedules for different satellites, different image resolutions and different data acquisition modes, i.e. ScanSAR Wide and Wide modes. DEM accuracy also proved to be an issue. Current work is underway to improve the satellite image acquisition planning and DEM accuracy and increase the number of gauge stations in the flood affected area so as to improve the accuracy, reliability and usefulness of geoinformatics data for future disaster management.