Geoinformation assessment of floods in the Barguzin River basin
T.A. BORISOVA, A.N. BESHENTSEV, S.A. PETROV
Baikal Institute of Nature Management, Siberian Branch, Russian Academy of Sciences, Ulan-Ude, Russia
Keywords: digital elevation model, geomorphometric analysis, hazard, risk, hydrological data, mapping
Abstract
The article presents the results of the analysis of archive materials of the long-term (1936-2015) observations of floods on the Barguzin River. A digital elevation model was created for geomorphometric analysis of the river basin relief. Automated analysis of relief indices in the Saga GIS software environment and expert interpretation of Landsat images from different periods 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 was carried out, their genesis was determined, and metric characteristics and features of passage in different parts of the basin were identified. Maps of average water levels and flooded areas were compiled. The flood zone mapping was 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 was collected from long-term observation series, and calculated 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 were used. The combination of layers of hydrological sites and flood zones with the layer of agricultural lands made it possible to establish the average long-term values of flooding of the territory for hydrological sites, and to 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 were compiled.
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