MILWAUKEE RIVER

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The Milwaukee River Watershed includes three main branches: the North Branch, East–West Branch, and South Branch. In total, the watershed spans about 700 square miles across Fond du Lac, Dodge, Sheboygan, Washington, Ozaukee, and Milwaukee counties. The Milwaukee River originates in Fond du Lac County and flows for approximately 100 miles before joining the Menomonee and Kinnickinnic rivers in the Milwaukee River Estuary, where the system empties into Lake Michigan.

The Milwaukee Metropolitan Sewerage District’s (MMSD) jurisdiction of the Milwaukee River is limited to the portions of the river that are within Milwaukee County, and this only includes portions of the South Branch of the river. 

In addition to the Milwaukee River mainstem, MMSD also has jurisdiction over the following Milwaukee River tributaries: Lincoln Creek, Southbranch Creek, Indian Creek, Beaver Creek, and Brown Deer Park Creek. 

Land use varies across the watershed. Agriculture dominates much of the North and East–West Branches, while the South Branch is more urbanized, with dense residential, commercial, and industrial development. 

Problem

Development across the watershed has changed how water flows throughout the area. Streams and tributaries such as Beaver Creek and Southbranch Creek were reshaped to move water quickly through growing communities, but studies showed that they could not handle modern stormwater volumes. During heavy rain, water levels can rise beyond what the streams were designed to carry, increasing the risk of flooding of nearby roads, neighborhoods, and businesses. There are an estimated 543 structures remaining in the one-percent annual probability floodplain of the Milwaukee River mainstream and tributaries. 

Other tributaries in the watershed, including Lincoln Creek, Indian Creek, Southbranch Creek, and Beaver Creek, face similar challenges. The reports, Milwaukee River in Milwaukee County Upstream of the Milwaukee Harbor Estuary and the Milwaukee River Watershed Phase 1, found that many of these waterways have limited access to their natural floodplains which reduces their ability to store or slow down stormwater.  

As urban development increased, so did impervious surfaces. During heavy rain or snowmelt, large volumes of runoff are rapidly delivered to streams, often exceeding the capacity of both natural channels and older flood infrastructure and leading to increased flooding in some communities. These conditions contribute to higher flood risk and long-term impacts on the Milwaukee River Watershed, tributaries, and the communities they flow through. 

Additionally, some tributaries of the Milwaukee River, such as Lincoln Creek, were lined with concrete in the 1960s to reduce the risk of flooding. However, this created fast, dangerous flows, endangering the safety of nearby residents and increasing the risk of flooding for the community.   

Solution

MMSD’s Greenseams® program is essential to flood management within the Milwaukee River Watershed. By storing and draining water into the ground naturally, Greenseams® helps reduce future flooding and water pollution. Additionally, the Working Soils® program aims to permanently protect privately held working land in the Milwaukee River watershed floodplain.

Healthy soils store rainwater, recharge groundwater and reduce water pollution. Both initiatives happen upstream, which significantly aids in flood management and water quality further downstream. 

Stormwater basins are also a significant engineering tool used to manage flooding within the tributaries of the Milwaukee River. Stormwater basins are reservoirs built to temporarily hold stormwater during heavy rain and snowmelt events. Their purpose is to prevent high volumes of water from quickly flowing into nearby streams, which can lead to flooding and water contamination. By capturing and storing stormwater, these basins help manage runoff effectively and protect the surrounding communities.

MMSD Flood Management Work

Kinnickinnic River Flood Management Projects

Menomonee River Flood Management Projects