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

[1] The map of the province of Quebec drawn up in 1870 by Eugène Taché indicates this watercourse in the form "R. The Ombrette”.

The nickname Lombrette, joined to the name of Pierre Simard or Cimar in the census of 1666–1667, still remains enigmatic.

If it is not the name of a farm or a place known as the country of origin of Pierre Simard in the surroundings of Angoulême, if need be, the ombrette can be the diminutive of shade, a bony fish that is distinguished from salmon, trout and char by its small mouth.

[2] The toponym "rivière Lombrette" was formalized on August 29, 1972 at the Place Names Bank of the Commission de toponymie du Québec.