Upstream, the waters of this river are coming from Decelles Reservoir, located east of the lake.

[1] In 1928, the "Commission géographique du Québec" (Geographic Board of Quebec) formalized this name that evokes the work of Télesphore Simard.

Working for the Government of Quebec, Simard explored the rivers of the North Coast and Temiscamingue.

This name will be replaced by the English name "Expanse", probably as a result of the construction, circa 1912, of a dam on rapid of the Fifteen (French: Rapides des Quinze); which would significantly increase the surface area of the lake.

The word that comes close to Algonquin Winneway, meaning "white water" refers to a particular bay and an island in the southeast of Lake Simard.