Flood Hazard on the Rivers of the Baikal Region

A comprehensive characterization of the flood hazard on the rivers of the Baikal region is presented, which was obtained by investigating the streams within the basins of the Angara, Upper Lena (with the Vitim and Olekma), Lower Tunguska (headwaters), Upper Amur and Lake Baikal (including the entire Selenga basin). The main flood indicators for the period 1985–2017 are estimated: the genesis, recurrence, duration, flooded area and the force of impact. The influence of changes in the river runoff characteristics on the flood risk is shown by results of correlation analysis and analysis of integro-differential curves. An assessment is made of the changes in the flood frequency at gauging stations during the period of pronounced climatic changes (from 1981 to 2014), compared with the earlier period. The flood hazard within the spatial context for municipalities in the rank of administrative districts is determined on the basis of the dual (socio-economic and natural) nature of floods. It has been confirmed that the most dangerous in the Baikal region are rainfall floods in the southern areas of Irkutsk oblast, the Republic of Buryatia and Zabaikalskii krai. They have the highest frequency, and the largest flooding areas and force of impact and are characterized by the greatest damage and by the largest number of victims and evacuated people. At the same time, the frequency of floods at gauging stations in recent years has decreased compared to the earlier period against the background of the observed low-water period, which is most pronounced on the rivers of South Baikal and in the Selenga river basin.