The Zagorsk pumped-storage station (PSS) is the first large pumped-storage station in a series of unified PSS being constructed in the central zone of the European USSR.On the basis of construction experience, it is possible to distinguish certain general problems characteristic for many PSS: small volume discharge of the streams used for filllng the reservoirs (dry-weather flow up to 1 mS/sac); presence of artificial lower and upper reservoirs on weak foundations; extreme diversity of the geological bedding caused by glacial activity; high specific volumes of earthworks per unit capacity (about 40 mS/kW); absence of rock quarries for concrete and filters.Under these conditions the wide use of traditional hydraulicking methods of performing earthworks was rather problematical, which was reflected in discussions during an examination of the technical design.However, the acute shortage of vehicles and the complete absence of noncoheslve materials at the very start of construction accelerated the decision about creating a department of hydraulicklng works. Hydraulicklng was supposed to solve three problems: supplying the construction with noncohesive rock materials; excavation of the foundation pit of the PSS with simultaneous hydraulic filling of the 500-kV outdoor electrical equipment yard; hydraulic filling of the downstream dam with an impervious core.