Use of geographic information and remotely sensed data in the decision-making support system for flood management in Romania

Abstract

Flooding is an important risk in many areas around the globe and especially in Romania. In the latest years flooding occurred quite frequently in Romania, some of which isolated, others were affecting wide areas of the country's territory. The paper assumes a modern approach for the flooding risk indices, associated to the physic-geographical, morpho-hydrographical and vulnerability characteristics of a region. The objective of this study is to establish a methodology that should further allow determining the flooding risk, using representative indices at a scale compatible with a synthetic representation of the territory. There are stressed the facilities supplied by the Geographic Information System (GIS) and the remotely sensed data to manage flooding during their characteristic phases: before, during and after flooding. Accent is laid on the pre- and post-crisis phases. An important research topic was the study of the parameters that can be extracted from satellite images in view of organizing a hierarchy of the geographical space versus the flooding risk. Although satellite sensors cannot measure the hydrological parameters directly, remote sensing can supply information and adequate parameters to contribute to identify and map the hydrological risk at the basin level. There is various information deriving from analyzing high spatial resolution satellite images. In this respect, a series of criteria were determined from the radiometric information contained in image-data concerning the biophysical and anthropical parameters of basins. The morphological characteristics were extracted by image processing and from the Digital Terrain Model (DTM). Information obtained from satellite images proved to be useful for the determination of certain parameters necessary to monitor flooding: hydrographic network, water accumulation, size of floodable surface, land impermeability degree, water absorption capacity over the basin surface, or resilience to in-soil water infiltration. The nature of this information through the spatial and temporal coverage attributes may contribute to build complete databases suitable to allow simulations or scenarios. The study encompassed both the risk degree levels related with various parameters, which influence and determine flooding and which takes into consideration the human presence in the sensitive areas. This approach implies establishing also the vulnerability degree function of the costs of human and material nature that flooding may determine. The application was developed for the Arges hydrographic basin in Romania, a critical area, keeping in mind that it withholds many localities, including the capital and also important economic centers. Advantages offered by this integrated system are: to manipulate and make available large databases, to easily update the information, to survey the temporary modifications, to establish the link between the measured/forecasted data and the GIS database. The database allows obtaining synthetic representations of the hydrologic risk for the Arges basin through separate or combined use of the risk parameters as well as for interfacing with the hydrological models in view to improve them as regards recovering results and the possibility to achieve scenarios.