Freshwater Resources Monitoring

The Freshwater Resources Monitoring group conducts routine surface water monitoring at nearly 100 fixed monitoring sites within the MMSD Planning Area. Field measurements and grab samples are taken 1-2 times per month at these sites and brought to the in-house certified laboratory for analysis. Up to 41 different parameters are sampled at each site.

The MMSD Planning Area includes the Milwaukee River, Menomonee River, Kinnickinnic River, Root River, Oak Creek, and Lake Michigan Direct Drainage watersheds. However, some of these boundaries extend outside of the Planning Area. 

Click on the sites on the map to learn more.

To summarize the large amount of data collected each year, the Freshwater Resources Monitoring group produces an annual report, focusing on a specific subset of parameters and/or sites. This report focuses on surface water quality in 2020 for chloride, E. coli (EC), fecal coliform (FC), total phosphorus (TP), and total suspended solids (TSS) for routine monitoring data (does not include targeted monitoring). These parameters of interest are aligned with current projects MMSD is involved in to support the work of our partners.  ​

Check out the last page of this report to learn more about these projects!​

In addition, WDNR recently adopted new E. coli standards for surface water to replace fecal coliform. The effects of switching to this new standard are further explored in terms of compliance.

The tables show the percent of samples meeting surface water quality criteria for all sites in 2020. When possible, Wisconsin 2020 Consolidated Assessment and Listing Methodology (WisCALM) guidance and criteria found in WI Administrative Code Chapters NR 102 (EC  ¹ , TP ² ), 104 ³  (FC), 105 ⁴  (chloride) and the Milwaukee River Basin Total Maximum Daily Load ⁵  (TSS) were used.

​MMSD is not responsible for ensuring that surface water meets water quality standards. MMSD’s Jones Island and South Shore WRFs’ effluent discharges to the Harbor and nearshore of Lake Michigan. Different than surface water quality criteria listed in the WI Administrative Code, the water quality-based limits for effluent are established in MMSD’s Wisconsin Pollutant Discharge Elimination System permit. 

Click on the watersheds on the map to view the results.

Footnotes:

 ¹  Wis. Admin. Code § NR 102.04 (May 2020) The E. coli standard is based on a geometric mean of 5 or more samples per 90-day window, but for the purposes of this report, the criterion is used as a benchmark for water quality.

 ²  Wis. Admin. Code § NR 102.06 (May 2020).

 ³  Wis. Admin. Code § NR 104.06 (February 2004) The fecal coliform standard is based on a geometric mean of 5 or more samples per month, but for the purposes of this report, the criterion is used as a benchmark for water quality.

 ⁴  Wis. Admin. Code § NR 105.06 (July 2010).

 ⁵  CDM Smith. 2018. Total Maximum Daily Loads for Total Phosphorus, Total Suspended Solids, and Fecal Coliform Milwaukee River Basin, Wisconsin. Final Report. USEPA Region 5, March 19, 2018. 147 p.

Due to the COVID-19 pandemic, sampling was reduced by nearly 50% in 2020. Monitoring was suspended March 16th and resumed June 1st at a limited capacity. 

1. The typical high discharge events associated with heavy spring precipitation events were largely missed. Discharge graphs in the map show a rise in spring discharge based on long-term daily medians: on the Milwaukee and Menomonee rivers and Cedar Creek this occurred during March – May.
2. The reduced number of samples in 2020 may not be representative of overall water quality conditions.  Even with limitations, sampling generally covered a wide range of discharge, but several watersheds missed the opportunity to sample all hydrograph regimes (once per month). For example, Honey Creek/Underwood Creek were first sampled in June.
3. Because water quality data are variable, it is important to monitor on a regular basis during all conditions. Results differ each year due to varying precipitation amounts and frequency, site-specific conditions, and other factors that affect compliance.  The results in this report show mixed compliance compared to last year: 22% of all parameters compared had changed compliance categories. See  previous year's report  for a more in-depth analysis regarding this.

​Click on the watersheds to view the discharge graphs (example below) with sampling dates.  

E. coli and fecal coliform are used as indicators of the presence of disease-causing pathogens in surface water. Sources of these bacteria include rural and urban sources such as manure application, wildlife, and leaking sewer laterals.  Approx. 90% of the bacteria loads in these watersheds are from both urban and rural runoff ⁵ .

In May 2020, the WDNR adopted changes to NR 102 Water Quality Standards for WI Surface Waters that removed fecal coliform criteria and replaced it with E. coli. E. coli is known to be a better predictor for illness due to human fecal contamination of surface water and therefore more protective for human health in recreational waters. 

The new rule also removed variances for waterbodies that could not meet the historical criteria (also known as secondary contact recreation water). All water bodies are now considered full recreation water and must meet the statewide E. coli criteria.

Important to note: This rule is separate from the TMDL.  The goal of the TMDL is to reduce pollutant loads in discharges to the streams so that surface water quality standards will be met. The TMDL was developed for fecal coliform and therefore effluent limits in WPDES permits may still be based on fecal coliform. 

With less than a year since the adoption of this rule, the Freshwater Resources Monitoring historical dataset can be used to help us understand the impacts*. The animation shows each site's percent compliance as it transitions through the three parts. 

1. Percent compliance was calculated for each site under the historic fecal coliform criteria. 
2. Where applicable, the fecal coliform variance criterion was removed to isolate its contribution to compliance. Removing the fecal coliform variance drastically reduces compliance in sites where the variance applies. 
3. Percent compliance was calculated for all sites using E. coli.  Switching the bacterial indicator to E. coli has a similar negative impact on compliance at all sites, though to a lesser extent when compared to removing the variance. All sites included within the analysis had substantially reduced compliance when applying the new E. coli criterion. The largest changes were observed for sites within the Milwaukee River Estuary with one site dropping from 83% to 8%.  Under the new rule, no site had more than 20% compliance in all assessment periods.

With only 16 sites located on reaches listed for an E. coli impairment on the 303(d) Clean Water Act list, our data show that applying the new E. coli criteria across the area may dramatically increase the number of waterbodies with impairments. MMSD currently routinely monitors for E. coli at 44 of 91 sites.  This highlights a need for continued and expanded E. coli monitoring.

*Each data set was calculated following the DNR rules in table above. Both the historical and new bacteria criteria specify a minimum data frequency. In order to meet this requirement, five years of data were pooled for each site. Data collected during targeted monitoring were removed so that analysis could focus on baseline conditions.