The lake is formed by the damming of two rivers, Möhne and Heve, and with its four basins stores as much as 135 million cubic metres of water.

In 1904, calculations about the future demand for water for people and industry in the growing Ruhr-area determined that the existing storage volume of 32.4 million m³ in dams of the Ruhr river system needed tripling.

A 77 m by 22 m hole was blown in the dam with the resulting floodwave killing at least 1,579 people,[1] 1,026 of them foreign forced labourers held in camps downriver.

Though the Organisation Todt quickly repaired the dams through the labor of 7,000 men taken from the construction of the Atlantic Wall, the impact of the raid on German industry in the Ruhr valley and on the civil population was significant.

According to Albert Speer, "the power plant at the foot of the shattered dam looked as if it had been erased, along with its heavy turbines."

An important reason for greater resting occurrences of diving ducks and coots is the presence of the migratory mussel in the lake.

When the water level rose sharply in December 2006, the eiders could no longer reach the zebra mussel beds and left the lake.

In addition, whitefish, eel, pike, zander, brown trout, bream, carp, tench and chub are also found.