Geoinformation Assessment of Floods in the Barguzin River Basin

This article presents the results of an analysis of archive materials of the long-term (1936–2015) observations of floods on the Barguzin River. A digital elevation model is created for geomorphometric analysis of the river basin relief. An automated analysis of relief indices in the Saga GIS software environment and expert interpretation of Landsat images from different periods has made it possible to differentiate the basin territory into homogeneous hydrological sites characterized by similar physical and geographical parameters of flood development. An assessment of flood formation is carried out, their genesis is determined, and metric characteristics and features of passage in different parts of the basin are identified. Maps of average water levels and flooded areas are compiled. Flood zone mapping is performed in the ArcGIS software environment based on the interpretation of Landsat satellite data from different periods and a topographic base at a scale of 1 : 100 000. As hydrological information for obtaining absolute flood zone boundary elevations, a sample of maximum water levels is collected from long-term observation series, and water levels at the cross sections obtained from the distribution curves of annual probabilities of exceeding maximum water levels of rain floods for hydrological posts are used. The combination of layers of hydrological sites and flood zones with the layer of agricultural lands has made it possible to establish the average long-term values of flooding of the territory for hydrological sites and determine the areas of flooded agricultural lands and settlements. A probabilistic-areal approach was used for the cartographic assessment of risk from floods. The risk calculation procedure is based on hazard indicators through a vulnerability parameter, allowing us to determine the physical risk or damage to the territory, economic facilities, and the population (in specific indicators), which forms the basis for calculating economic risk. Specific maps and an integrated risk map are compiled.