Contribution of Earth Observation Data Supplied by the New Satellite Sensors to Flood Disaster Assessment and Hazard Reduction

Abstract

The risk of flooding due to runoff is a major concern in many areas around the globe and especially in Romania. In the latest years river flooding and accompanying landslides, occurred quit frequently in Romania, some of which isolated, others-affecting wide areas of the country’s territory.

The main objective of the NATO SfP project “Monitoring of extreme flood events in Romania and Hungary using EO data” is to improve the existing local operational flood hazard assessment and monitoring using the functional facilities supplied by the GIS info-layers, combined with Earth Observation (EO) data-derived information, Digital Elevation Models (DEM) and hydrological modeling. The study area is situated in the Crisul Alb - Crisul Negru - Kőrős transboundary basin, crossing the Romanian — Hungarian border.

The orbital remote sensing can provide necessary information for flood hazard and vulnerability assessment and mapping, which are directly used in the decision - making process. The EO data-derived information of the land cover/land use is important because it makes possible periodical updating and comparisons, and thus contribute to characterize the human presence and to provide elements on the vulnerability aspects, as well as the evaluation of the impact of the flooding. In order to obtain high-level thematic products the data extracted from the satellite images must be integrated with other geo-information data (topographical, pedological, meteorological data) and hydrologic/hydraulic models outputs.

The paper presents the specific methods developed for deriving satellite-based applications and products useful for flood disaster assessment and hazard reduction. An important contribution of EO derived information in the topic of managing flooding connected phenomena could be envisaged at the level of mapping aspects. Using the optical and microwave data supplied by the new satellite sensors (U.S. DMSP/Quikscat, RADARSAT, LANDSAT-7/TM, EOS-AM “TERRA”/MODIS and ASTER) different products like accurate updated digital maps of the hydrographical network and land cover/land use, mask of flooded areas, multi-temporal maps of the flood dynamics, hazard maps with the extent of the flooded areas and the affected zones, etc. have been obtained. These results, at different spatial scales, include synthesis maps easy to access and interpret, adequate to be combined with other information layouts resulted from the GIS database and to ingest rainfall-runoff models outputs.

The presented applications will contribute to preventive consideration of the extreme flood events by planning more judiciously land-use development, by elaborating plans for food mitigation, including infrastructure construction in the flood-prone areas and by optimization of the flood - related spatial information distribution facilities to end — users.