US COUNTRY STUDIES : Mississippi River

The Mississippi River is a tributary of the Ottawa River in eastern Ontario in Canada. It is 200 kilometres (120 mi) in length from its source in Upper Mazinaw Lake, has a drainage area of 4,450 square kilometres (1,720 sq mi), and has a mean discharge of 40 cubic metres per second (1,400 cu ft/s). There are more than 250 lakes in the watershed.

From its headwaters at Mazinaw Lake to its confluence at the Ottawa River near Fitzroy Harbour the river drops 323 metres in elevation. It begins on the rugged lands of the Canadian shield (mostly gneiss and marble), and then, after Carleton Place, flows through limestone and clay plains. At Carleton Place, there are rapids with limestone cliffs. This area supports the largest stand of hackberry trees in the region.

Communities along the river include the Village of Lanark, the towns of Carleton Place, Mississippi Mills (including former towns of Almonte and Pakenham), and Galetta. Here it enters the Ottawa River.

Most of the upper landscape is temperate deciduous forest dominated by sugar maple, american beech and red oak. At one time, the forests had much more hemlock, but this was logged out to produce bark for the tanning industry. Now, large hemlock stands are uncommon. Most forests are relatively young, that is, less than a century old.

The irregular terrain of the watershed was arises out of an old mountain chain which was once higher than the Himalayas. It has since been eroded to mostly gneiss and marble hills, with occasional outcrops of granite. Lower in the watershed, there are younger limestone rocks. Most of these are covered by clay deposited when this area was covered by the Champlain Sea.

Occasional large wetlands occur along the river. One of the largest is the Innisville Wetlands, a provincially significant wetland that is also designated and Area of Natural and Scientific Interest.Another large wetland is the Appleton Silver Maple Swamp. These wetlands depend upon the seasonal cycles of the river. High water periods in the spring flood large areas creating wetland soils, and large areas of marsh. As water levels slowly fall, conditions suitable for swamp forests occur. This natural seasonal alternation between high and lower water levels is essential for creating the natural diversity of wetlands along the river.

Downstream, where the Mississippi enters the Ottawa River, there are several important shorelines and wetlands, including the Mississippi Snye, which has a rich aquatic flora over marble bedrock, and has recorded observations for the musk turtle

Tributaries include the:

Clyde River
Indian River
Fall River
Bell's Creek

The river originally powered textile mills. Today, it provides hydroelectric power. Such power dams, however, have all but eliminated american eels from the river; these were once an abundant source of food for aboriginal populations, as well as providing a source of food for herons and otters, among other animals.The origin of the river's name is something of a mystery; although its current spelling may be derived from that of its much larger American cousin, it is most certainly a corruption of a different native name, as the translation 'great water' would not apply to a relatively minor tributary of the Ottawa, definitely the largest river in the area. Instead, the name may originate from "Mazinaai, Algonquian for ' image river', referring to the pictographs found on Mazinaw Lake, though this is by no means proven.