The main reasons for the occurrence of floods of different genesis in the river basins of Angara, Nizhnyaya Tunguska, Lena and Lake Baikal within the Irkutsk region are studied. Based on the analysis of the collected materials, the work considered the natural prerequisites for the occurrence of floods in the Irkutsk region, the main ones are: 1) floods resulting from an increase in river runoff during spring or spring-summer snow melting floods and summer rainfall floods; 2) floods caused by the collision of a water flow with an obstacle in the river bed during ice damming and jamming. The most important parameters in flood hazard analysis are maximum runoff and water levels. The maximum runoff of spring snow melting floods and summer rainfall floods at hydrological posts was analyzed, and an inventory of river sections with ice-dam and ice-jam was carried out. The result of the work was the zoning of the territory of the Irkutsk region according to the genesis of floods. The method of conjugate analysis was used, based on identifying the relationships between individual components of nature (geomorphological structure, climatic conditions and water regime of rivers). The use of the method of conjugate analysis made it possible to identify nine areas (Biryusinsko-Udinskij, Vostochno-Sayanskij, Verkhneangarskij, Sredneangarskij, Leno-Angarskij, Verkhnelenskij, Pribaikalskij, Tunguskij and Vitimo-Patomskij), differing in the water regime of rivers and natural conditions for the river runoff formation. The performed zoning of the Irkutsk region territory has both practical and theoretical significance. The results of this study can be used in educational institutions, in the Ministry of Emergency Situations, as well as in scientific activities, to obtain modern data on the causes and nature of the spread of floods within the Irkutsk region.

Slepneva Elena Valeryevna, Candidate of Sciences (Geography), Associate Professor, Department of Geography, Cartography and Geosystem Technology, Irkutsk State University, 1, K. Marx st., Irkutsk, 664003, Russian Federation, e-mail: physgeo@geogr.isu.ru 

Parygina Elizaveta Aleksandrovna, Student, Faculty of Geography, Irkutsk State University, 1, K. Marx st., Irkutsk, 664003, Russian Federation, e-mail: lizavetaparygina@yandex.ru 

Kichigina Natalia Vitalievna, Candidate of Sciences (Geography), Senior Researcher, Laboratory of Hydrology and Climatology, V. B. Sochava Institute of Geography SB RAS, 1, Ulan-Batorskaya st., Irkutsk, 664033, Russian Federation, e-mail: nkichigina@mail.ru

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