Mississippi River Basin Freshwater in Average Year

Runoff is generally highest when there is high rainfall, precipitation near the mouth is greater than in the western potion and this is shown by the higher levels of run-off estimated for the river mouth. The spring period from March to May is when the highest flows are expected in the basin with August to October experiencing low flows. One recent flood period is the upper basin occurred in 1993 and was attributed to rains in late winter and the summer months.

Freshwater Legend (mm/month)

Bargraph referencing the colours on the evaporation maps.

Other Mississippi Maps

Mississippi Freshwater Maps