The upper part has mountainous relief and is accessible only by secondary forest roads including Chemin Careau (coming from the north).

The water level of the river varies with the seasons and the precipitation; the spring flood occurs in March or April.

[1] Known since 1851, this toponym evokes the memory of Jean Cassaux (around 1699-1761), surgeon, originally from the town of Issor in Béarn, in France.

The spelling of his patronym used in the name of the river will subsequently include the letter z notably in an act of land concession in 1750.

[2] The toponym "Rivière Cazeau" was formalized on December 5, 1968 at the Place Names Bank of the Commission de toponymie du Québec.