Floodplain Delineation Based on Analysis of Digital Elevation Model, Soil Maps and Occurrence of Quaternary Formations

This paper presents a GIS based method of indicating flood extent in a mountainous river basin. Only main river with the valley is object of this analysis. The approach used in this work combines analysis of digital elevation model (DEM) obtained from LIDAR data with presence of alluvial soils and quaternary formations. In addition, in this article an attempt of calculating flood wave height for delineated floodplain is presented. The results are compared with floodplains derived from one of the products of country-scale project „IT system for protection against extraordinary hazards” (ISOK) which are flood hazard maps and with the extent of The Great Flood of 1997. Indication of the area flooded during Poland’s Great Flood in July 1997 is based on the hydrological data from Institute of Meteorology and Water Management – National Research Institute (IMGW – PIB).