Increasing the capacity of navigation locks is a very important sector of the Russian Federation inland waterway transport development. One of its directions is the structure of the flow in the navigation lock discharge system investigation,using modern methods of mathematical modeling. Calculations on the numerical model, described in this paper, allow to analyze the hydrodynamics of water flow that occurs when the chamber is drawdowned, and evaluate the work of flow energy quenching system at the outlet of the tailrace. This article presents a standard dampers design and their disadvantages, two new flow energy dissipation systems are proposed. The high efficiency of these systems (in comparison with already existing systems) is proved by mathematical modeling, their using can significantly improve the vessels placing conditions and increase the capacity of navigation facilities.