Two Distinct Watersheds


watershed_webThe Mississippi River (above) is just over 200 km in length. Draining over 250 lakes and wetlands, the watershed encompasses an area of 3,750 km². From its headwaters at Mazinaw Lake to its confluence at the Ottawa River near Fitzroy Harbour, the river drops 210 m in elevation.  Together with drainage areas of the Carp River and local flow to the Ottawa River, MVCA has a total jurisdiction of 4353 km².

From Mazinaw Lake, the river follows an easterly course towards Mississippi Lake, meandering through the many lakes and reservoirs. In Lanark, it picks up volume of two of its major tributaries, the Clyde and Fall Rivers. It then flows north through the towns of Carleton Place, Almonte, and Pakenham and eventually enters the Ottawa River near Arnprior.

The Landscape was formed over millennia by glacial erosion. Its irregular terrain changes from exposed bedrock, dense forest and plentiful wetlands of the Canadian Shield in the west, to the managed rolling farmland and urban centers of the Ottawa Valley.

The Soil is steep granite and shale formations with shallow soil cover in the west. Leda clay is abundant in the eastern part of the watershed.
Many types of natural habitats, such as forests, rocky highlands, farm and wetlands, meet and overlap to create a diverse home for plants and animals, while providing lots of recreational opportunities for watershed residents seeking a natural retreat


The Carp River watershed is an important natural ecosystem that is located entirely within the City of Ottawa. The river is 42 km long and drains an area of 306 km². It is predominately urban in the headwaters in Stittsville with the remainder of the watershed in a rural state, reaching its endpoint at Fitzroy Harbour.

MVCA is working with the City of Ottawa to develop a long-term environmental management strategy that is necessary to protect, enhance or restore environmental quality in light of current and future demands on the river’s resources. To achieve these goals, the subwatershed plan provides an overall strategy including development guidelines and a monitoring protocol.