The Dominique river runs from north to south for with a vertical drop of. It has one important tributary, the Foins River, which drains the southeast of the basin. The mouth of the river is in the municipality of Port-Cartier in the Sept-Rivières Regional County Municipality. At its mouth in the city of Port-Cartier the river converges with an arm of the Aux Rochers River in the Rivière-aux-Rochers Park. A trail in the park leads to the Rivière Dominique waterfall. The origin of the name, which was made official on 5 December 1968, is not known.
The northern part of the Dominique River basin is on a deeply dissected rocky plateau in which slopes can rise by. The highest point is in the north of the basin. The piedmont region extends for between the plateau and the coastal plain. It is formed of rounded rocky hills up to high. The coastal plain is a strip of fairly flat land about wide that gradually slopes down to sea level from in the north. The bedrock is dominated by magmatic rocks, deformed to some extent, of migmatite, granitoid rocks and granitic gneiss. The plateau and piedmont area include vast areas where the bedrock is exposed. In other places there is glacial till of up to in depth, and in the main valleys there are large glaciofluvial sediments. In the coastal plain the Goldthwait Sea deposited large amounts of clay and silt sediment as it followed the retreat of the glaciers after the last ice age. As the land rebounded from the weight of the ice, the sea retreated and the marine sediments were covered by coarser sandy estuarine and deltaic sediments.
Hydrology
Waterbodies cover 5.72% of the Dominique River basin. The main lakes are Lake Morin at and Little Lake Anguille at. Ombrotrophic peatlands cover 6.15% of the basin, mostly on the coastal plain where the flat relief and fine sediments retain the water. The rivers and streams follow angular courses dictated by fractures in the hard bedrock. Upstream the rivers follow rather rectilinear courses through narrow valleys, but downstream they meander slightly through the loose deposits of the coastal plain. The annual average flow at the Dominique River mouth is estimated at, varying during the year from.
Environment
The Pentecôte weather station, to the southwest of the river mouth, records an average annual temperature of and annual average rainfall of. A map of the ecological regions of Quebec shows the upper and central Dominique River in sub-regions 6j-T and 6m-T of the east spruce/moss subdomain, and the lower part in sub-region 5g-T of the eastern fir/white birch subdomain.. On the coastal plain the forest cover is dominated by stands of balsam fir, white spruce and paper birch, with lesser numbers of jack pine, larch and trembling aspen. Further inland in the spruce-moss region the forest cover is dominated by black spruce, with balsam fir and, to a lesser extent, hardwoods such as paper birch, trembling aspen and balsam poplar. Fish species are American eel and brook trout. There are rainbow smelt at the mouth of the river. The Dominique River is not recognized as an Atlantic salmon river.
Conservation
The watershed is almost entirely contained in the Port-Cartier–Sept-Îles Wildlife Reserve. This reserve, with a total area of, covers of the Dominique River basin, or about 87.5%. The proposed Lake Pasteur Biodiversity Reserve extends into the west of the watershed. It is a protected area under IUCN category III, established in 2003. The proposed reserve covers a total area of of which are in the Dominique watershed, covering 18.0% of its area including Lake Morin and Little Lake Anguille. On the Gulf of St. Lawrence the river basin adjoins the Port-Cartier West Waterfowl Concentration Area.
