Assessment of the possibility of operating low-pressure hydroelectric facilities in order to improve the conditions of navigation in their lower reaches

Abstract

Abstract The paper provides an assessment of the projected low-pressure hydroelectric facility operation on the Volga River from the point of view of navigation conditions in its lower reach. The operating mode of the low-pressure hydroelectric facility completely depends on the hourly discharges of the Nizhny Novgorod HPP, located upstream. Significant unevenness in time of the supplied discharges from the Nizhny Novgorod HPP, which, repeating itself when discharging flows into the lower reach of the Nizhniy Novgorod low-pressure hydroelectric facility, can lead to negative consequences for shipping in terms of failure to provide transport passes and necessary depths. It is proposed to reduce the unevenness of discharges by introducing diurnal flow regulation into the low-pressure hydroelectric facility operation, aimed at changing the hydrological regime of the river section to improve the conditions and organize uninterrupted and safe navigation in the lower reach. Achievement of the regulation goal associated with minimization of interval deviations of the supplied flow rates from Nizhny Novgorod HPP from the daily average values and the fulfillment of the restrictions on the hydrological regime of the low-pressure hydroelectric facility ponds, is achieved by two control options (three-stage and two-stage). The study used the methods of mathematical statistics and probability theory, optimization of management decisions. The methodology of the mathematical model limitations’ nonfulfillment elimination for solving the problem and optimization of the low-pressure hydroelectric facility daily hydrograph is presented. Using a specific example, the problem of diurnal regulation of discharges is solved and the obtained effect is described.