Purpose: checking the headrace canal to the fall no. 1 for diversion capacity in connection with a change in the canal discharge. Due to the increase in the estimated flow for irrigation and watering, it is planned to build a canal from the reservoir to the fall no. 1. The tasks of the hydraulic computation included the determining of the headrace canal parameters for the intended catastrophic water discharge of 375 cubic m/s, the computation was carried out taking into account the non-steady flow in canal. For effective energy extinction in the tail-race of the fall, it is required to make a constructive decision and carry out a justification taking into account the topographic conditions of the structure's operation. It is necessary to resolve the issue of energy extinction in tail-race of the structure. Calculations of the toothed overfall for energy extinction in the tail-race are presented. Materials and methods. A version of the dissipator with an indented wall which allows dissipate energy in the constraint environment effectively and obtain a favorable distribution of velocities in the flow in tail race of the structure was adopted for the computation. A step-by-step computation for determining the diversion capacity of the fall no. 1 was carried out: first, the diversion capacity of the headrace canal was determined at a catastrophic discharge Q = 375 cubic m/s with a subsequent change in its hydraulic parameters, then the computation for dissipating the flow energy in the downstream of the structure are given. Results: the calculations of the jagged sill for damping the energy in the tail-race are presented, the indented wall of the fall is designed and the corresponding depths in the tail-race are calculated. Conclusions: the performed computation of the headrace canal and fall no. 1 made it possible to ensure the passage of a catastrophic flow rate equal to 375 cubic m/s, under set conditions.