Abstract
The article identifies unresolved problems on ensuring the safety of low-pressure hydraulic systems, due to the specifics of a number of unfavorable factors. When studying the predicted parameters of the breakthrough wave, which are used in calculating flood damage in the event of an accident of medium and low-pressure dams, it was revealed that its main parameter, which determines the impact area coefficient values, is the maximum flooding depth. Based on the simplified graphic-analytical methodology of Istorik B.L., by using the experiment planning method principles, a method was developed for preliminary expert assessments of the flooding depth in the downstream of low-pressure hydraulic systems in the event of their waterfront breakthrough. Application of the proposed equation will allow carry out preliminary expert assessments of the emergency scale.