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Mississippi River Watershed

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The Mississippi River is 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.

The Mississippi River watershed is home to incredible natural heritage features such as wetlands, areas of natural and scientific interest (ANSIs), woodland and natural heritage systems. They include:


  • Burnt Lands Alvar: Areas of Natural and Scientific Interest (ANSIs) are sites containing natural landscapes or features MNRF ID's as having important values for natural heritage protection, scientific study or education. ANSIs are categorized as life or earth science.


  • Appleton, Goulbourn: Wetlands cover 489km or 13% of the total Mississippi River watershed area? Large wetlands are located around Mississippi Lake, and in parts of the lower watershed near Appleton.


  • Marble Lake: Stromatolites or stromatoliths are layered mounds, columns, and sheet-like sedimentary rocks that were originally formed by the growth of layer upon layer of cyanobacteria, a single-celled photosynthesizing microbe. Fossilized stromatolites provide records of ancient life on Earth. (Wikipedia)

Flood Forecasting & Warning

Flood forecasting is one of the most important services that Mississippi Valley Conservation Authority provides to our residents and member municipalities. A timely warning of upcoming high-water conditions is critical to helping everybody to prepare and be better able to respond.

Our flood messages are sent to the media, posted on our website and shared on our social media channels. You can subscribe to receive MVCA flood messages via email. The following, colour coded symbols describe the watershed conditions. This is always indicated throughout our website.

Normal status indicates that no flood conditions exist. However, even during Normal conditions, the inherent risk to personal safety associated with flowing water still exists.

Watershed Conditions Statement - Water Safety: High flows, unsafe banks, melting ice, or other factors that could be dangerous for recreational users such as anglers, canoeists, hikers, children, pets, etc. Flooding is not expected.

Watershed Conditions Statement - Flood Outlook: Early notice of the potential for flooding based on weather forecasts calling for heavy rain, snow melt, high wind or other conditions that could lead to high runoff, cause ice jams, lakeshore flooding, or erosion.

Flooding is possible in specific watercourses or municipalities. Municipalities, emergency services, and individual landowners in flood-prone areas should prepare.

Flooding is imminent or already occurring in specific watercourses or municipalities.

Low Water Response

MVCA in partnership with the Ministry of Natural Resources and Forestry helps in the coordination and support of local response in the event of a drought as part of the Ontario Low Water Response Program.

The Low Water Response Program has three condition levels. The levels are based on trends in rainfall and flows.

Low Water Response Program Status

NORMALWater levels are within acceptable parameters.
Level IFirst indication of potential water supply problems, primarily a warning level – key focus is conservation of water.
Level IIIndicates a potentially serious problem – conservation of water is extended to restrictions on non-essential uses.
Level IIIIndicates a failure of the water supply to meet demand – Key focus is on regulation & enforcement.