Winnebago River

Watershed at a Glance

The Winnebago River watershed drains a total of 440,244 acres (688 square miles). Only about 10% of the area is in Minnesota, the rest is in Iowa. The headwaters of the Winnebago River are in Freeborn County in southern Minnesota, where Bear and State Line lakes, along with several streams and ditches, drain to creeks that flow to the Winnebago River. This river flows 72 miles in north Iowa through Forest City and Mason City, joining the Shell Rock River at Rockford, Iowa.

Hydrologic Unit Code:07080203
Intensive monitoring start year:2013
Major lakesMajor rivers and streams
Bear, Emmons, State Line
Steward Creek, Lime Creek, Freeborn County Judicial Ditches 25 and 25, County Ditch 79


The vast majority of the Winnebago River watershed is cropland (73%). The other major land uses include pasture or hayland (11%), developed for urban use (9%), water (4%), and woodland and natural areas (3%).

Bear Lake is a large and shallow lake, encompassing 1,560 acres at the ordinary high water level with a mean depth of 2.1 feet and maximum depth of 4 feet. In 1972, the Minnesota Department of Natural Resources designated Bear Lake as a Wildlife Management Lake. It suffers from a large population of invasive rough fish, and high levels of suspended sediments, algae, and total phosphorus. All major measures of lake water quality point to a hypereutrophic (very highly productive for algae) lake condition. Total phosphorus averages about 229 parts per billion (ppb), whereas a healthy shallow lake in this region should be around 90 ppb. Chlorophyll, a measurement of algae, averages about 91 ppb, whereas a healthy lake should be about 30 ppb. Water clarity measure only about 0.4 meters during spring and summer, compared to 0.7 m for a healthy lake. 

State Line Lake, located in the town of Emmons on the Iowa border, is a 445-acre lake. Water clarity during the spring and summer averages about 0.2 to 0.3 meters.  There is limited water quality data available for this lake, which is surrounded by housing, farmland, and Gateway Park in Emmons.

What's being done

The Winnebago watershed will be part of the MPCA’s intensive watershed monitoring in 2013, which includes studying fish and bug populations along with measuring water clarity and other parameters. This effort will involve monitoring both Bear and State Line lakes. The MPCA will use the monitoring data to determine the health of streams and lakes in this watershed.

In 2010, the Minnesota DNR started a lake and watershed improvement effort for the Steward Creek and Bear Lake subwatershed. The total watershed area is 24,901 acres, and also includes the Freeborn County Ditch 79 subwatershed. DNR staff worked across traditional divisional boundaries and with local government to provide information on the lake and watershed, and to help guide a future direction for improved lake conditions. The DNR developed a publication called “The Bear Lake Watershed Story, a guide to water quality and watershed health” and provided it at meetings. This effort is ongoing among the DNR, local governmental units, and watershed landowners.

Monitoring and assessment reports

PDF icon Winnebago River Watershed Stressor Identification Report (wq-ws5-07080203a)

What is a watershed?

Illustration showing contour of land directing flow of water

Learn the basics of a watershed.

Skip Wright, Regional Hydrologist, Minnesota DNR


Cathi Fouchi, Regional Planner


Freeborn County Environmental Services


Freeborn County Soil and Water Conservation District

507-373-5607, Ext. 3