| South Mékinac River | |
| Pushpin Map: | Quebec |
| Subdivision Type1: | Country |
| Subdivision Name1: | Canada |
| Subdivision Type2: | Province |
| Subdivision Name2: | Quebec |
| Subdivision Type3: | Region |
| Subdivision Name3: | Mauricie |
| Subdivision Type4: | Regional County Municipality |
| Subdivision Name4: | Mékinac Regional County Municipality |
| Length: | 17.8km (11.1miles) |
| Source1: | Lake Gabriel |
| Source1 Location: | Grandes-Piles |
| Source1 Coordinates: | 46.7517°N -72.695°W |
| Source1 Elevation: | 292m (958feet) |
| Mouth: | North Mékinac River |
| Mouth Location: | Saint-Tite |
| Mouth Coordinates: | 49.8308°N -64.3781°W |
| Mouth Elevation: | 138m (453feet) |
| River System: | Nivo-pluvial |
| Tributaries Left: | (upstream) Discharge from a small lake, discharge from a lake, discharge from a lake, discharge from two streams (via Lac Tessier), discharge from two small lakes (via Lac des Caribous). |
| Tributaries Right: | (upstream) Ruisseau Rouille, ruisseau non identifié, décharge du lac du Castor (via le Lac à la Truite), décharge de deux petits lacs (via le Lac à la Truite). |
The Rivière Mékinac du Sud (English: South Mékinac River) is a watercourse flowing from Grandes-Piles to Saint-Tite and Hérouxville in Mékinac Regional County Municipality (RCM), Mauricie, administrative region, Quebec, Canada.
This river has two main sources in the Laurentian Mountains, at Grandes-Piles:
Upper course
From Lac à la Truite, the waters descend for a kilometre to empty into Lac Tavibois (length: ; altitude:) at Grandes-Piles, located in the Tavibois area. A retention dam has been built at its mouth with automated control of the water level; this dam is located on the boundary between Grandes-Piles and Hérouxville. After this dam, the water crosses a fall to flow further southeast into Lake Léo (length: ; altitude:) which has a small dam at its mouth. This lake flows eastwards into Tessier lake (length: ;) that the current crosses on towards the North. The lake collects a stream (coming from the north) which drains the western slope of Le Chaudron mountain (altitude:) which straddles the limit of Saint-Tite and Hérouxville, almost at the limit from Grandes-Piles.
From the dam at the mouth of Lake Tessier, the current heads northeast over, towards Le Chaudron mountain, before turning southeast to descend on crossing Chemin des Petites-Forges, up to a stream (coming from the northeast). From there, the course of the river heads south on first by forming serpentines, then crossing the Petit lac du Castor (length: ; altitude:) and very narrow), to the dam located at its mouth, south of the lake. About thirty chalets surround the Petit lac du Castor.
From this last dam, the current descends towards the south-east, crosses towards the north a small narrow lake (length: ; altitude:) to the small dam at its mouth. From there, the current flows on eastward, forming two hooks, one north, the other south, to the discharge (coming from the north) of a lake. Then the current goes to, first over south to a stream (coming from the south), then on eastward crossing Lake Ayotte (length: ; altitude:) whose dam is located in the camp Val Notre-Dame, then on south-east to the mouth of Ruille stream (coming from the south).
Lower course
From there, the river heads northeast on where it crosses the Saint-Tite boundary. Then the river crosses another in the zone to cut the route 159. And the mouth of the Mékinac du Sud river is further away, as the water flows into the North Mékinac River.
On most of its route, approximately (measured by water) from the mouth of lac à la Truite (or from lac Jean-Baptiste), the river flows mainly in a forest environment. In short, the river runs in Grandes-Piles, in Hérouxville because of the streamers and in Saint-Tite.[1]
The toponym Rivière Mékinac du Sud was formalized on December 5, 1968, at the Place Names Bank of the Commission de toponymie du Québec.[2]