Sediment Contamination Monitoring

The Program and partners conduct sediment contamination testing at six locations in the Milwaukee River. The goal of the sediment monitoring is to provide initial characterization of location and extent of contaminated sediment deposits in Ozaukee County portions of the mainstem Milwaukee River.

Methods of sediment monitoring include:

Orthophoto Review

Review of historic
orthophotos from 1941 through current to identify 58 suspected areas of sediment deposition. Orthophotos assist staff with locating potential sediment deposit areas while in the field.

Sediment Poling
Confirm location, extent, and general composition of sediment deposits and to measure water depth to soft bottom and total depth to hard bottom. Sediment poling is used to determine the site where the sediment core samples will be taken from.


Sediment Coring

Sediment coring sites are prioritized by areas with the thickest soft sediment. A range of soft sediment depths (e.g, < 1’, 1-2’, 3-4’, > 4’) are sampled.

Sediment Coring Sites:
Site 1 (County Line)
Site 2 (M-T Impoundment) 
Site 3 (Downstream of Cedar Creek)
Site 4 (Newburg)
Site 5 (Bridge Street Impoundment)
Site 6 (Upstream of Grafton)

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Laboratory Analysis of Sediment

Levels of PCB contamination at each site analyzed using WDNR’s “Consensus-Based Sediment Quality Guidelines”. 
These guidelines establish “concern level” schemes at which toxicity to benthic dwelling organisms are predicted to be unlikely (TEC) and probable (PEC).

Threshold Effect Concentration (TEC)
Midpoint Effect Concentration (MEC)
Probable Effect Concentration (PEC)

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  • Likely source of contaminants (Cadmium) found at Newburg likely due to historical industrial operations in the City of West Bend. 
  • Contaminated sediment likely released during the abandonment of the Woolen Mills Dam and impoundment in 1988
  • Approximately 2,310 cu yards of sediment immediately behind the Newburg Dam was removed in 2012
  • Baseline data from sites 5 and 6 (upstream of Cedar Creek) indicates relatively low levels of PCB contamination in the Milwaukee River upstream of Cedar Creek
  • 77 samples exceeding TEC, MEC, and PEC for PCB’s at sites downstream of Cedar Creek
  • Cedar Creek and the Hamilton Pond is a likely source of contaminants (particularly PCB’s) to the Milwaukee River downstream of the Cedar Creek confluence

View the Final Sediment Contamination Report Submitted to the USEPA:

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