It is not one contiguous body of water, but the collective name for a series of connected lakes separated by innumerable bays, peninsulas, and islands with highly irregular shapes.

[3] Initially, the "Commission des eaux courantes du Québec" (English: Quebec Running Water Board) wanted to facilitate the floating of wood that was routed via the Saint-Maurice River, to the paper mills of La Tuque to Trois-Rivières.

A series of dikes and canals were needed to divert the water from these rivers and still today; these works are unknown to the general public.

Through the railway, the village became a supply depot and access point to the Rupert River, Mistassini Lake and other areas of northern Quebec.

These villages are located approximately 40 km (25 mi) south of the reservoir and are accessible by a forested road and by train with Via Rail.

Waterfowl present in the region include the American black duck (Anas rubripes), mallard (Anas platyrhynchos), green-winged teal (Anas crecca), ring-necked duck (Aythya collaris), common merganser (Mergus merganser), hooded merganser (Lophodytes cucullatus), common goldeneye (Bucephala clangula), bufflehead (Bucephala albeola), common loon (Gavia immer), Canada goose (Branta canadensis), bald eagle (Haliaeetus leucocephalus).

The main mammals in Haute-Mauricie are: moose, white-tailed deer, bears, hares, red foxes, muskrats, skunks and raccoons.

In its role of surveillance of the territory, this non-profit organization collaborates with the Ministry of Forests, Wildlife and Parks (MFFP) to maintain a good management of the fish resource.