Morphodynamics of the river mouth systems of the southern Baikal depression

Abstract

The researches covered the largest river mouths, representing the main morphogenetic types of river mouth systems (RMS) of tributaries of the southern depression of the Lake Baikal. On the coastal area of the southern depression there are 3 types of RMS: fewarm with channel opening or with a spit; multi-arm with phytogenous-delta coast (on the terrigenous cone); arched protruding deltas on a shallow seaside. The results of morphometric analysis in dynamics for the period from 1897 to the present time are presented. The various morphometric parameters and coefficients of development of the RMS are given. The increase in the level initially led to the flooding of the mouths and adjacent territories, and then to a new stage of development of the RMS at the «river-lake contact», both subaerial and underwater parts of them. An attempt was made to consolidate the concepts of river mouth system, river mouth area, and river mouth geosystem with the definition of the borders. The conclusions about the factors of formation of various RMS are presented: the water level regime of the receiving reservoir, hydro-climatic conditions, seismotectonic expressions, and the technogenic factor. The leading processes of relief formation at the present stage of development are revealed.