Iowa is sucseptable to extreme flooding especially around the Mississippi River.  Iowa, like most of the Midwest, has a humid continental climate throughout the state with extremes of both heat and cold. Iowa flooding occurs as a result of intense rainfall, icejams, and snow melting.  Ironically, the main-stem reservoirs built in-part to control floods may exacerbate the ice jam problem because low wintertime discharges might facilitate ice formation. The average annual temperature at Des Moines is 50 °F (10 °C); for some locations in the north the figure is under 45 °F (8 °C), while Keokuk, on the Mississippi River, averages 52 °F (12 °C). Winters are brisk and snowfall is common. Spring ushers in the beginning of the severe weather season. Iowa averages about 50 days of thunderstorm activity per year.  Tornadoes are common during the spring and summer months, with, on average, 37 tornadoes per year producing mass amounts of flooding.  The Iowa summers are known for heat and humidity, with daytime temperatures often near 90 °F (32 °C) and sometimes exceeding 100 °F (38 °C). 

Iowa is rich in water resources with six major river basins and more than 27,000 miles of perennial streams.

Channel alterations to almost 80% of Iowa streams have interrupted natural flow regimes, increased flooding, and decreased biotic diversity.

The Mississippi River has the third largest drainage basin ("catchment") in the world.  It drains 41% of the 48 contiguous states of the United States. The basin covers more than 1,245,000 square miles.