Lake Winnipeg is located on the northern fringe of the Canadian prairie where endless wheat fields and grasslands dotted with grazing cattle are characteristic of the landscape. The lake itself is surrounded by dense stands of elm, ash, basswood, maple and aspen, which bring, fleetingly, their gorgeous rich autumn color to the scenery.

The lake is composed of two basins; a wide north basin and a narrow south basin. The Nelson River, the only outflow of this lake, proceeds northward from the north basin to Hudson Bay. On the other hand, the Red River flows into the south basin with abundant loads of mud and nutrients washed out from the prairie. The city of Winnipeg is situated in the upper reaches of the Red River in the heart of Manitoba. The lake is so shallow in spite of its extensive area that the water remains always muddy due to wave and turbulent mixing by strong winds. The population density in the drainage basin is still very low, but the lake has been fairly eutrophicated by nutrient loading of the Red and other inflowing rivers.