ESTIMATION OF FREE SURFACE AND DEPTHS DYNAMICS IN DOWNSTREAM OF NIZHNY NOVGOROD HYDROPOWER COMPLEX WHEN CONSTRUCTING THE THIRD LINE OF LOCKS OR THEIR THIRD STAGE

Abstract

The shipping locks of the Nizhny Novgorod hydropower complex and the Gorodets-Nizhny Novgorod section limit shipping in the Integrated Deep Water System. Dredging, carried out since the 1970s to maintain design depth, has had a great impact on the water level in the downstream of the Nizhny Novgorod hydropower station. The solution of the problem of shallow depths on the site and the passage of the Gorodets locks by the vessels is possible by building a low-pressure hydroelectric complex in the area of B. Kozino. In order to estimate the impact of the construction of the third lock line, as another alternative solution of the problem proposed by a number of authors, hydraulic calculations of the behavior of water free surface at the site and at depths were performed. The movement of the water flow in the riverbed was described by a system of differential equations of motion. As a result of the calculations, it was found that the free surface curve at a flow velocity in the range of 800–1500 m3/s does not reach the position of the curve at the design level. This indicates the insecurity of the design shipping depth on the site. Alternatives to hydraulic structures in the form of the third line of Gorodets locks or the third stage in the approach channel will not provide the necessary navigation depth. Downstream channel will be radically deformed, and additional dredging in the downstream site will lead to the water levels landing on the sills of existing locks No. 15–16 and the site.