The objective of the research was to assess the dependence of natural drainage of the soils of Predbaikalye on orography. The calculation was based on natural drainage of Predbaikalye morphometric indices (main slope areas; total length of all streams of the river basin, which is considered as the base of erosion; total area of the river basin; the difference in elevation of its source and mouth; the length of the elementary stream flow). Statistical treatment of the results was carried out using the program STATISTICA 10.0. The research methods included descriptive statistics, such as the Shapiro-Wilk test criterion, probability plots, and the dispersion analysis according to Kruskal and Wallis. The lowest significance of the descriptive statistics of natural drainage corresponds to the Irkutsko-Cheremchovskaya plains and the Kansko-Taishetskaya plains. For the Leno-Angarskoe plateau, the Predbaikalye basin and Angarsky ridge the significance was higher, and the highest significance was found for the region of the Eastern Sayan Mountains. The application of the Shapiro-Wilk test shows that the values of the most common indicators of the various orographic units conflict with a normal distribution, except for the values of the Predbaikalye basin. By applying the Kruskal-Wallis test, which is a non-parametric analog of the one-factor dispersion analysis, the dependence of natural drainage on orography was established.
Keywords: natural drainage, Predbaikalye, melioration, orography, groundwater.
