Construction of large hydroelectric complexes on the plain rivers of Western Siberia, such as the Ob, as well as other types of anthropogenic impact (infill development, quarrying of nonmetallic building materials, carrying out track works, laying communications, wastewater discharges, etc.) lead to a change in water and channel regimes, hydrological characteristics, channel deformation in the downstream. One of these changes is the landing of water level in the section of the lower pond of the Ob from the Novosibirsk hydroelectric complex to the mouth of the Tom River, which adversely affects navigable conditions of this stretch, operation of water intakes, port and sluice, and also damages the fish industry. The landing of the water level continues to this day, and in order to maintain the design water level, it becomes necessary to increase navigation releases. The design level was changed several times after the commissioning of the Novosibirsk hydroelectric complex due to its low availability, a further change in the availability will lead to a change in the design level mark, or rather its lowering. Therefore, the purpose of the study is to assess the position of the design flow rate at the established design level and make a forecast of changes in water flow depending on the time that has passed since the start of operation of the Novosibirsk hydroelectric complex, taking into account the impact on the channel, carried out dredging works, as well as other types of anthropogenic impacts.