Impaired Water - Cedar Creek (Cedar Creek)
Ozaukee County, Wisconsin
MI02, MI04
0.00 - 5.00
Water is impaired due to one or more pollutants and associated quality impacts.
This segment of Cedar Creek was put on the Impaired Waters List for PCB contaminated fish tissue and sediment. This site has legacy sediment contamination. The TMDL for PCBs was approved in 2008. Evaluation of fish and bug communities in the 2020 and 2022 cycles showed them in good condition.
Listing Details
Listed For
Fish Consumption
PCBs Contaminated Fish Tissue
Current Use
Specific Restricted Fish Consumption
Listing Status
TMDL Approved
Attainable Use
Unrestricted Fish Consumption
Not Applicable
Designated Use
Unrestricted Fish Consumption
303(d) ID
Listing Date
Impaired Water Notes
The Cedar Creek and Milwaukee River watershed is located in Ozaukee County, in southeastern Wisconsin. The Problem Statement of the TMDL submittal identifies the listed reaches for the watershed as including Cedar Creek (WBIC 21300, stream miles 0-5), and the Milwaukee River (WBIC 15000, stream miles 3-28). During the development of the TMDL, WDNR resegmented the Milwaukee River into two segments, and addressed the upper portion of the Milwaukee River in this TMDL submittal.

The Cedar Creek segment includes open stretches of the creek as well as several ponded portions, including Ruck Pond, Columbia Pond, and Wire and Nail Pond. These are formed behind dams on the creek. The Milwaukee River segment includes the open stretch of the river as well as the Thiensville
impoundment, a 700-acre impoundment formed behind the Thiensville Dam.

Land Use: The land use is described in the Problem Statement Section of the TMDL submittal. For the entire Cedar Creek watershed, the land use is mainly agricultural (49%), wetlands (16%), grasslands and forest (26%) and urban about 3.5% (Page 3 of the TMDL). The Cedar Creek segment addressed by the TMDL flows through the City of Cedarburg, and is therefore more
urbanized. The Milwaukee River watershed is more mixed, with 33% urban, 25% agricultural, 21% grasslands, 12% forest, and 6% wetlands. The Milwaukee River segment begins in the village of Grafton, and ends in the village of Thiensville (Figure 1 of the TMDL).

The Cedar Creek and Milwaukee River watershed was listed on the 2006 Section 303(d) list due to fish consumption advisories due to polychlorinated biphenyls (PCBs). In the 1970’s, WDNR detected PCBs in sediments and fish in Cedar Creek. Investigation and remediation has been underway by WDNR and the USEPA Superfund program to address the PCB contamination. Fish tissue monitoring has been conducted for many years in the watershed. A fish consumption advisory (FCA) has been placed on Cedar Creek for all fish species.

This FCA states that no fish of any species should be consumed from Cedar Creek. For the Milwaukee River, numerous species are under either a “no more than 1 meal per month” or a more restrictive FCA due to PCBs.

Source Identification: The Source Assessment Section of the TMDL submittal discusses how PCBs entered Cedar Creek and Milwaukee River through industrial discharge at two facilities in Cedarburg, Wisconsin. The PCBs were discharged from the facilities via stormwater and industrial discharge. PCBs still exist on the sites, and significant amounts of PCBs are present in the sediments in the waterbodies. Stormwater runoff from the contaminated facilities is the only current source of PCBs other than the instream sediments (Page 11 of the TMDL). These contaminated sediments are transported downstream by scouring and resuspension of sediments during higher-flow events.

WDNR identified two National Pollutant Discharge Elimination System (NPDES) permitted point source discharges in the Cedar Creek segment, the Cedarburg Wastewater Treatment Facility (ID #0020222) and the Wilshire stormwater retention basin (WI-S049972-2). WDNR does not believe that the WWTP facility is an active source of PCBs, based upon effluent sampling (Page 11 of the TMDL) but did determine a WLA. Wilshire Basin is considered a minor source by WDNR, as the basin receives stormwater run-off from the contaminated sites. This run-off contains PCB-contaminated sediments, and under significant run-off conditions, could discharge to Cedar Creek (Page 11 of the TMDL).

WDNR believes that the source of PCBs in the Milwaukee River is sediment transported from Cedar Creek (Page 12 of the TMDL). WDNR did not identify any active sources of PCBs on this segment, other than from contaminated sediments being transported downstream through normal river processes, although further investigation is on-going.

Impaired Water Notes
Cedar Creek is a 28-mile, warm water stream that runs through Washington and Ozaukee Counties of Southeastern Wisconsin and flows into the Milwaukee River at river mile 28. The land use in the Cedar Creek Watershed is primarily rural including agriculture (49%), wetlands (16%), grasslands and forest (26%), while urban areas cover about 3.5% of the watershed (WNDR 2001). The Wisconsin Department of Natural Resources (WDNR) placed the first 5 miles of Cedar Creek upstream of the confluence with the Milwaukee River on Wisconsin’s 303(d) Impaired Waters List for Fish Consumption Advisories (FCAs)1 due to PCBs in contaminated sediments.

Cedar Creek contributes to an annual average PCB mass of approximately 5 kg to the Milwaukee River (BBL, 2005). Unfortunately PCB contamination caused by releases decades before is still present today because of the persistent nature of these chemicals.

The impaired segment of Cedar Creek flows through the Town of Cedarburg before reaching the Milwaukee River, and includes open stretches of stream as well as areas known as Ruck Pond, Columbia Pond, Wire and Nail Pond, and the former Hamilton Pond; the dam of the latter failed in 1996 and was permanently abandoned shortly thereafter. These portions of Cedar Creek and of the impaired Milwaukee River Segment 2 are classified as a Warm Water Sport Fish community, and supports a diverse fish community including: Bluegill, Black Crappie, Common Carp, Horneyhead Chub, Creek Chub, Common Shiner, Fathead Minnow, Bass, Northern Pike, Rock Bass, Largemouth and Smallmouth Bass, Walleye, Yellow Perch, Common White Sucker and four species of Redhorse (Greater, Silver, Shorthead and Golden).

Impaired Water Notes
The Cedar Creek & Milwaukee River PCBs TMDL was approved by the USEPA September 23, 2008.