The main motivation for the reconstruction of the control closures of the bottom outlets (BO) was mainly the current unsatisfactory technical condition of Johnson type caps on BO marked I and II and cylindrical closures on BO marked III and IV. More than 80 years have passed since their commissioning, during which time only routine maintenance and partial repairs have been carried out. The current state of this equipment, both in terms of corrosion and operational damage, does not guarantee long-term reliable operation. The aim was to restore full operational reliability, including sealing at the level of leakage values meeting current standard requirements, and to extend the service life to ensure the long-term safety of the entire hydrological structure (HS).
The aim of the research was to specify or supplement the results of the “Assessment of hydraulic conditions in the area of bottom outlets and the adjoining stilling basin of Vranov reservoir – reconstruction of outlets” prepared by prof. Ing. Jan Šulc, CSc. Another goal was to design the actual hydraulically tested variants of measures enabling safe transfer of affected flood flows Q1 – Q10000 by lower outlets with new end control segment caps at each bottom outlet and crest spillway with subsequent cascade and stilling basin.
As part of the research, two physical models were built, a model of a bottom outlet with an end segment closure at a scale of 1:14.68 and a spatial model of the dam body with outlet devices at a scale of 1:55.