Abstract <p>This study proposes an integrated approach to assessing the source (surface, groundwater, or mixed) of soil hydromorphism and its relative duration based on a multilevel analysis of soil morphological properties. Using soils from the bottoms of nine depressions in the southern part of the Oka–Don Lowland as an example, the combined application of macro-, micro-, and submicromorphological methods is demonstrated for the analysis of elementary soil-forming processes with different morphometric parameters and vegetation characteristics. An integrated analysis of the transformations of soil organic matter, clay pattern, and redoximorphic pedofeatures allows for diagnosis of the specific features of the gleying associated with the differences in hydromorphism between three genetic groups of depression soils: Oxygleyic Gleysols, Albic Mollic Gleyic Stagnosols, and Albic Mollic Histic Planosols. It is shown that the main factor in differentiation of their soil profiles is the interaction between the surface and ground moisture, which determines the duration of water stagnation and depth of the impact. Carbonized organic matter, diffuse boundaries of nodules, and the evident prevalence of iron in their composition indicate the long-term influence of hydromorphism caused by surface and groundwaters on Gleysols. In contrast, the presence of multilayer clay coatings and clearly defined redoximorphic features with prevalence of manganese indicates a short-term periodic hydromorphism with surface moistening typical of Planosols. Characteristic of Stagnosols is a mixed moisture regime with a shorter period of waterlogging as compared to Gleysols.</p>