Lakes in Iowa

Water has played a huge role in shaping Iowa’s land over the years, and our state’s lakes reflect the many different interactions of humans and water over time across our landscape. There are three primary processes by which lakes were formed in Iowa.

Glacial: Glaciers covered much of Iowa 10,000 years ago. As the glaciers gradually receded and chunks of ice broke off, the melting ice left behind basins that filled with water, forming some of Iowa’s most popular and iconic lakes (e.g., Iowa Great Lakes, Clear Lake, Black Hawk Lake). Bigger blocks of ice formed deeper lakes. Smaller blocks of ice formed shallower lakes and wetlands (e.g. prairie pothole wetlands dotting the north central Iowa landscape).

Fluvial: Fluvial lakes were formed by river processes. For example, the Mississippi and Missouri Rivers both have oxbow lakes associated with them (e.g. DeSoto Bend National Wildlife Refuge).

Human Activity: The majority of lakes in Iowa were formed by human activity. This includes the damming of rivers to form reservoirs (e.g., Saylorville Lake, Lake Red Rock, Lake Rathbun) for flood control, as well as constructed lakes (e.g. Ada Hayden Lake near Ames, constructed from a former gravel pit).

Iowa’s lakes are hotspots for recreation year-round—from boating, fishing, swimming, picnicking, and hiking in the warmer weather months, to ice-fishing and snowmobiling in the winter months. Nearly two-thirds of residents visit an Iowa lake each year, with water quality being the #1 most important factor in deciding which lakes to visit (Iowa Lakes Valuation Project).

Video Resources

Out to the Lakes – Iowa State University | Iowa Learning Farms

Enhanced Learning Activities

A Culture of Conservation Activity Booklet (Grades 6-12)

Additional Resources

Ambient Lake Monitoring – Iowa Department of Natural Resources

Iowa Lakes Valuation Project – Iowa State University