ИСТИНА

There are more than 700 cities and towns, thousands of villages and settlements, and more than seven million hectares of agricultural land of the Russian territory are exposed to a risk of flooding. Results of flood modeling for three cities located in different parts of Russia: Veliky Ustyug at Northern Dvina river (Europe); Yakutsk at the Lena river (Siberia) and Blagoveschensk at the Amur river (Far East) are presented. The two-dimensional hydrodynamic model of flow in channels and on floodplain STREAM_2D on the basis of the numerical solution of two-dimensional Saint-Venant equations was used for the simulations. One of the major challenges in mathematical modeling is the verification of the model. This is usually made using data on water levels from hydrological stations: the smaller the difference of the actual level and the simulated one, the better the quality of the model used. Alternative sources of verification, e.g. remote sensing, should be used where data is unavailable. Flooded areas obtained from hydrological modeling and satellite images interpretation have been compared. Satellite images made by optical and radar sensors: SPOT-5/HRG, Resurs-F, Radarsat-2 were used. Flooded areas were calculated using unsupervised classification for satellite images. Verification of the model through a comparison of simulated inundated areas with outlines of flooded zones from satellite images for known hydrologic situations demonstrate close correspondence (relative errors of 7-10% in terms of the area for peaks of the analysed floods). This study was supported by the Russian Science Foundation, project no. 14-17-00155.