[2] The reservoir is shaped highly irregularly, with many deep bays, dotted with islands in its western section, and characterized by a large rounded peninsula in the centre.

The Geographic Board reported in 1960 that "according to the missionaries of the Côte-Nord, the Innu had given this name to the lake in remembrance of their last fight with the Iroquois on Mount Pigmaugan (Pipmuacan) that overlooks the water."

The Pipmuacan Reservoir was formed in October 1953 when Hydro-Québec began construction on the dams and power plant of Bersimis-1.

In 2002, Hydro-Québec diverted part of the Portneuf River to the north into the Pipmuacan Reservoir to increase the capacity of the Bersimis power stations.

[4] The partial diversion of the Sault aux Cochons River is being studied to further optimize the operation of the existing stations.