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Milwaukee Estuary Area of Concern


About the Milwaukee Estuary AOC

The Milwaukee Estuary was designated an Area of Concern (AOC) in 1987 by the International Joint Commission because of historical modifications and pollutant loads that contributed toxic contaminants to the AOC and Lake Michigan. Sediments contaminated with PCBs (polychlorinated biphenyls), PAHs (polycyclic aromatic hydrocarbons) and heavy metals contribute to nearly all of the eleven beneficial use impairments within the original boundaries of the AOC. The rivers within the AOC were also historically modified (straightened and dredged) to accommodate large vessel commercial shipping. While Milwaukee still maintains a viable commercial port, some of the river reaches within the estuary are no longer maintained through dredging.


The original boundaries of the AOC included the lower 5 km of the Milwaukee River downstream of North Avenue Dam; the lower 4.8 km of the Menomonee River downstream of 35th Street; the lower 4 km of the Kinnickinnic River downstream of Chase Avenue; the inner and outer harbors; and the nearshore waters of Lake Michigan, bounded by a line extending north from Sheridan Park to the city of Milwaukee's Linnwood water intake.

In 2008, the boundaries of the AOC were expanded for the purposes of addressing sites that contributed significant loads of contaminated sediments to the estuary. These expanded portions of the AOC are associated with the beneficial use impairments that are directly connected to contaminated sediment (see Beneficial Use Impairments tab).

Remedial Action Plan

The DNR worked with community stakeholders to develop a Remedial Action Plan in 1991. Since that time, significant progress has been made towards improving conditions in the AOC. The Remedial Action Plan is updated regularly to summarize progress made in the AOC and share the path forward with our partners and stakeholders. It includes a summary of the progress towards removing beneficial use impairments and tracks progress on projects that are important for reaching delisting targets. The DNR is committed to making progress in the AOC in order to delist, or remove, the Area of Concern designation and continues to work with stakeholders to identify goals and actions necessary to address legacy contamination in the AOC.

The main priorities for the Milwaukee Estuary AOC include:

  • remediation of contaminated sediments in tributaries and nearshore waters of Lake Michigan;
  • nonpoint source pollution control;
  • improving water quality for recreation; and
  • enhancing fish and wildlife habitat and populations.

Community Engagement

Community Advisory Committee (CAC)

Stakeholders in the Milwaukee Estuary Area of Concern participate in and lead the Community Advisory Committee as the long-term voice and way for individual citizens to share their opinions and perspectives on how cleanup efforts affect the people who live and work in the community.

More information about stakeholder involvement and how to become a member can be found on the Community Advisory Committee website.

Community Advisory Committee History

Initial work to form a Community Advisory Committee was led by UW-Extension, who collaborated with a Stakeholder Delegation to provide education and outreach about the AOC. When the team formed, it consisted of twelve people representing a balance between public, private and nonprofit interests in the Milwaukee Estuary AOC. UW-Extension recruited volunteers for the initial team in Spring 2012. Today, there are ongoing membership opportunities to continue to represent the diverse backgrounds and concerns of people in the AOC. For more information on how to serve on the CAC, visit the Community Advisory Committee website.

Get Involved

To learn more about AOC news, community events, volunteer opportunities and more check out these resources and links to partner agencies.



On July 18, 2008, the EPA approved expanding the geographic boundaries for the Milwaukee Estuary Area of Concern (AOC). Evidence showing contributions of toxic substances from upstream sources has accumulated since the boundaries were originally drawn in 1980. This change more accurately reflects ecosystem impacts connected with the beneficial use degradation described in the Milwaukee Estuary Remedial Action Plan and subsequent documents. Several specific expansions are included in the plan.

  • Cedar Creek downstream from Bridge Road to confluence with Milwaukee River. This addition encompasses the entire Cedar Creek Superfund Site, which contributes sediments contaminated with PCBs to the Milwaukee River.
  • Milwaukee River and Lincoln Creek from confluence with Cedar Creek to North Avenue Dam. This addition includes the portion of the Milwaukee River influenced by contaminated sediments from Lincoln Creek and Cedar Creek. This also includes a large deposit of contaminated sediments located upstream from the Estabrook Park Dam.
  • Little Menomonee River from Brown Deer Road to confluence with Menomonee River, and Menomonee River downstream from confluence with Little Menomonee River to 35th Street. The Little Menomonee River contains the Moss American Superfund Site, which potentially contributes contaminated sediments to the Menomonee River.



Eleven of the possible 14 beneficial uses identified by the International Joint Commission are impaired or suspected to be impaired for the Milwaukee Estuary AOC.

  • Restrictions on dredging activities*
  • Fish tumors or other deformities*
  • Bird or animal deformities or reproduction problems*
  • Restrictions on fish and wildlife consumption*
  • Degradation of benthos*
  • Degradation of phytoplankton and zooplankton populations
  • Loss of fish and wildlife habitat*
  • Degradation of fish and wildlife populations*
  • Beach closings/Recreational restrictions
  • Eutrophication or undesirable algae
  • Degradation of aesthetics

*Beneficial Use Impairments that are denoted with an asterisk are linked to contaminated sediment cleanup timelines. Remediation of contaminated sediment in the Milwaukee Estuary AOC is key to addressing these beneficial use impairments.

Final BUI Removal Packages With Cover Letters


Links related to the Milwaukee Estuary AOC


A Toxic Legacy: Cleaning Up Milwaukee's Waterways

In this video, Milwaukee historian John Gurda shares the next steps in an ambitious plan to clean up the remaining historical pollution in the rivers and harbor of the Milwaukee Estuary AOC. A project agreement with federal, state and local partners launched in 2020 leverages funding and offers a shared path forward to accelerate cleanup of the remaining contaminated sediments in the AOC. In scale, speed and impact, it's a historic opportunity to remove toxic pollution that is preventing our region from reaching its full potential. This project is vital to restore the health of our waterways and to open economic opportunities for Wisconsin and the Great Lakes region.

Built on Water: Milwaukee's Vital Resource

Lake Michigan and the rivers that feed it have been Milwaukee’s dominant natural resources since the days of the Potawatomi. Join historian John Gurda for a lively, illustrated look at the lake and its adjacent waterways. See how they served the community and how they have weathered a cycle of heavy use to emerge as focal points of both concern and celebration in the 21st century.

Milwaukee River Estuary Area Of Concern: A Community Returns To Its Rivers

The Great Lakes Restoration Initiative has brought federal dollars to Wisconsin to assist with the cleanup and restoration of five Areas of Concern (AOCs) - seriously polluted sites on the Great Lakes in need of special attention. Work in the Milwaukee Estuary AOC is returning these valuable resources to the people of Milwaukee.

Milwaukee River Estuary Area Of Concern: Connecting Milwaukee's Youth

With the help of federal funds and the hard work of local agencies, citizens groups and businesses, the DNR is breathing new life into Milwaukee's rivers and returning them to the community and to Milwaukee's youth as an urban oasis. Public parks and organizations such as the Urban Ecology Center connect kids and families to the waterways in their neighborhoods.


Sediment Projects

Sediment Projects Status and Map

Fish and Wildlife Projects

Fish and Wildlife Habitat Projects Status and Map

  • MMSD Menomonee River Concrete Removal
  • Little Menomonee River Parkway Grassland Restoration
  • Burnham Canal Wetland Restoration
  • Grand Trunk Wetland Restoration
  • Milwaukee River Fish Habitat Enhancement and Expansion
  • Wheelhouse Gateway Riparian Restoration
  • Kletzsch Park Dam Fish Passage
  • Estabrook Dam Fish Passage
  • Five Low Flow Barriers on the Menomonee River
  • Kinnickinnic River Habitat Rehabilitation
  • Little Menomonee River Corridor Restoration

PFAS Study

PFAS Sampling Results in the Federally Designated Milwaukee Estuary Area of Concern

The DNR performed surface water and sediment sampling to determine if PFAS (per- and polyfluoralkyl substances) are present in areas that are targeted for potential remedial dredging across the federally designated Milwaukee Estuary Area of Concern (AOC). These sampling results are now available.

Please direct any questions about the results to:

Christine Haag
Remediation & Redevelopment Program Director