A general tendency of river entrenchment is found in the center of Russian Valley from 60-70 to 25-30 thousand years ago (calendar) выявлена общая тенденция врезания рек. In many cases (Protwa, Moscow rivers) it was accompanied by formation of abnormally large meanders - macrobends. This allows linking entrenchment with significant increase in river flow. Probably, there were several periods of increased flow alternating with low-water intervals. By the beginning of the last glacial maximum (LGM), the rivers have entrenched to the level of the present rivers or deeper. The cryoarid time of LGM (20-23 thousand years ago (calendar)) was the most pronounced low-water period. Upon completion of LGM, the last period of strong flow has occurred during 13-18(19) thousand years ago (calendar). In this period numerous relict macrobends were formed and most of modern floodplains developed. Thus, the Valdai era was characterized by contrasting changes in surface flow. 

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