Milwaukee River Basin

The Milwaukee River Basin is an 882.3-square-mile area housed within Milwaukee, Waukesha, Washington, Ozaukee, Fond du Lac, Sheboygan, and Dodge Counties that includes the Milwaukee, Menomonee, and Kinnickinnic River Watersheds. Together, these watersheds contain approximately 500 miles of perennial streams, more than 400 miles of intermittent streams, 35 miles of Lake Michigan shoreline, 57 named lakes, and over 1.3 million people.

The Milwaukee River Basin is divided into three main watersheds:

  • Milwaukee River Watershed
  • Menomonee River Watershed
  • Kinnickinnick River Watershed

The Milwaukee River Watershed is also divided into four main subwatersheds:

  • North Branch Milwaukee River Subwatershed
  • East & West Branch Milwaukee River Subwatershed
  • Cedar Creek Subwatershed
  • South Branch Milwaukee River Subwatershed

The Milwaukee River Basin also includes the Milwaukee River Estuary.

The Natural Heritage Inventory has documented 16 endangered, 26 threatened and 65 special concern plant and animal species and 30 rare aquatic and terrestrial communities within the basin. The Southeastern Wisconsin Regional Planning Commission (SEWRPC) identified over 18,000 acres of high-quality natural communities and critical species habitats remaining in the basin. About 18% of the land area of the basin is covered by urban uses, while the remainder is considered rural. Agriculture is still dominant in the northern half of the basin.

Lake Michigan supplies drinking water to about 70 percent of basin residents as a function of population size. The remainder of the population receives their drinking water from groundwater sources. As people move to the more rural areas of the basin, groundwater quantity and quality issues will become more important.


Milwaukee River Basin’s Past

Before intensive settlement, the Milwaukee River Basin was much different than it is today. Historic settlements of four Native American groups—the Fox, Mascouten, Potawatomi, and Menominee—were documented along the Milwaukee River, and remained in the area for a short time after their lands were ceded to the United States around 1833. Some of these groups became involved in the fur trade with French explorers during the 1700 and 1800s. Pere Jacques Marquette was the first European explorer known to have visited what is now Milwaukee. He and the other explorers who followed found an area rich with upland forests of maple, beech and basswood, and lowland areas dominated by tamarack, cedar and ash.

In addition to the forests, the basin was water and wetland rich. The abundant resources of the forests, rivers and lakes were catalysts for the first settlers’ attempts at economic development in the basin. The southernmost portions of the basin, now known as the Milwaukee area, were soon settled and incorporated, while many of the forested riverbanks were cut for lumber or cleared for farming. Further north in the basin the land was rapidly deforested and cleared for agriculture. The relatively flat landscape and rich soils formed by the glaciers in many areas of the basin allowed for farming a variety of crops. By the mid-late 1800s, farming was the main activity in the upper basin,while mill operations were the first industries. The Milwaukee River and Cedar Creek provided excellent hydropower for the mills.


River Inhabitants

The number of fish found in the Milwaukee River Basin vary depending on if you count Lake Michigan species or not. Some studies count Lake Michigan species that enter the river such as Coho and Chinook salmon, but do not count fish that might stray into the lower part of the river such as lake trout. A rough cross-reference reveals 54 different species of fish.

There other inhabitants than fish in the Milwaukee River Basin however. Invertebrates play a significant role in the ecosystem of a river. In fact, the types of critters you might find can help determine the health of a stream.

Basin Fast Facts

Number of Main Watersheds

Miles of perennial streams in the basin

Different species of fish

Endangered, threatened and special concern plant and animal species