Zillergründl Dam


The Zillergründl Dam is an arch dam on the Ziller River in the upper Ziller Valley of Tyrol state, Austria. It is east of Mayrhofen. The primary purpose of the dam is hydroelectric power production and it supports a 360 MW pumped-storage power station. As part of the Zemm-Ziller Development, construction on the dam began in 1981 and it along with the Häusling Pumped Storage Power Plant were complete in 1986. The power plant was fully commissioned by 1988. The dam is the second tallest in Austria.

Design and operation

At an elevation of above sea level, the Zillergründl is a tall and long variable-radius arch dam with a structural volume of. The dam is wide at its crest and at its base. Its reservoir has a capacity of, of which is active capacity. At normal levels, the reservoir has a surface area of. The reservoir operates at elevations from to which is the draw-down level.
Water released from the reservoir reaches the Häusling Power Plant downstream. The power plant is located at an elevation of and contains two 180 MW Francis turbine-generators. It is afforded of hydraulic head given the difference in elevations. Using its pumped-storage capability, the power-station receives water from the Stillupp Reservoir to the west in an adjacent valley at and pumps it up to the Zillergründl Reservoir. The pumping and replenishment of the reservoir occur at night, during low energy demand periods. The process is repeated; electricity is generated during high-demand periods and pumping occurs during low-demand periods when electricity is cheaper.