Estimation of Groundwater Flow for the Central Eastern Sayan Rivers

The results of estimating the groundwater flow for the rivers of the Eastern Sayan, which includes 89 individual watersheds, are presented. Most of the river basins (left tributaries of the Angara River) are located in a fold-mountain area and are poorly covered by the data of the routine observations of river runoff. The groundwater flow of the rivers was determined by a complex hydrological and hydrogeological method of genetic hydrograph separation, taking into account a removal of a part of the flow for the aufeis formation. For unexplored rivers, the groundwater flow was determined by the method of transition coefficients for unit water discharges obtained during the hydrometric survey in the winter low-water period. In the fold-mountain area, the specific groundwater flow varies over a wide range and depends on the landscape and climatic conditions, as well as on the hydrogeological conditions of specific watersheds associated with the presence of permafrost and differences in tectonic activity in different parts of the study area.