Eggberg basin, reservoir in Germany

The Eggberg basin is a large water reservoir located near Rickenbach above the Säckingen cavern power plant in Baden-Württemberg. Situated about 400 meters above the facility below, it holds approximately 2.2 million cubic meters of water that flows through a vertical pressure shaft to generate electricity.

The Eggberg basin is the upper reservoir of the Säckingen cavern pumped-storage plant, operated by the Schluchseewerk. It also collects natural inflow diverted from the Murg, Ibach and Dorfbach rivers through a 12.5 km free-flow tunnel. The basin has a ring dam of rockfill with an asphalt concrete outer seal. Its lower reservoir is the impounded High Rhine, where the Säckingen run-of-river plant also stands.

The basin takes its name from the Eggberg hill above Bad Säckingen. Its water comes not only from the pumped circuit but also from natural inflows diverted from the Murg, Ibach and Dorfbach rivers through a 12.5 km free-flow tunnel, so the reservoir also collects mountain stream water.

The basin sits on the Eggberg above Bad Säckingen, reached on foot from the surrounding heights; the dam is a ring of rockfill with an asphalt-concrete seal on its outer face. Water arrives not only from the pumped circuit but also through a 12.5 km open-channel tunnel from the Murg, Ibach and Dorfbach. The Rhine weir below, with its run-of-river power station, marks the lower end of the system.

The maximum fall from the basin to the Rhine, impounded by a weir as the lower reservoir, is 410.72 m when the river stands at 289.28 m above sea level. The same weir feeds the run-of-river Rheinkraftwerk Säckingen, so one river serves both plants.