The establishment and maintenance of guaranteed dimensions of the ship's passage on the waterway requires an integrated approach. First of all, this is due to the influence of the level regime of the water body on the increase in the depth of the watercourse, taking into account the possible setting of the water level. Navigation conditions of the river Vyatka in the lower reaches largely depend on the influence of the support of the Kuibyshev reservoir. The authors substantiated the areas of support within the boundaries of the investigated area from the Vyatskiye Polyany hydraulic bridge to the Sokolyi Gory hydraulic bridge, conducted studies on the calculation of water level setting during the development of shipping slots. As a result, it was revealed that it is possible to establish guaranteed dimensions on the Lower Vyatka in a section from the mouth of the river to 40 km, including the city of Mamadysh. In the upper section of the river, the hydraulic features of it do not provide a reasonable opportunity to establish the specified dimensions of the path.