Waukesha County, Wisconsin
MI03
18400
0.00 - 4.70
4.70
Water is impaired due to one or more pollutants and associated quality impacts.
Notes
This water was placed on the impaired waters list in 2010 for Recreational use impairments due to bacteria. This segment of Lilly Creek was evaluated every two-year cycle from 2014 to 2024; chloride levels were elevated. Evaluation of phosphorus, temperature, and bug data showed good conditions. This water is covered by the Menomonee River Watershed Nine Key Plan, approved in January 2022.Pollutant
Chloride
Listed For
Fish and Aquatic Life
Impairments
Chronic Aquatic Toxicity
Current Use
Unsupported Aquatic Life
Listing Status
303d Listed
Attainable Use
Default - Fish and Aquatic Life
Priority
Low
Designated Use
Default - Fish and Aquatic Life
303(d) ID
2016-010
Listing Date
4/1/2016
Impaired Water Notes
This water was assessed during the 2016 listing cycle and chloride sample data exceeded 2016 WisCALM chronic listing criteria for the Fish and Aquatic Life use.
Date
8/21/2015
Impaired Water Notes
This water was assessed during the 2018 listing cycle; new chloride sample data exceed 2018 WisCALM listing criteria for the Fish and Aquatic Life use.
Date
4/11/2017
Pollutant
Fecal Coliform
Listed For
Recreation
Impairments
Recreational Restrictions - Pathogens
Current Use
Restricted Recreation
Listing Status
TMDL Approved
Attainable Use
Recreation
Priority
Not Applicable
Designated Use
Recreation
303(d) ID
2010-40
Listing Date
4/1/2010
Impaired Water Notes
The Milwaukee River Watershed TMDL was approved by the EPA on March 9, 2018 and covers waters in the basin impaired for Total Phosphorus, Sediment/Total Suspended Solids, and bacteria (E. coli and Fecal Coliform).
Date
3/9/2018
Impaired Water Notes
Lilly Creek is impaired due to recreational restrictions because of high bacteria levels (Fecal Coliform) in the creek. Fecal coliform levels exceed 400 CFU/100 ml 31% of the time on an annual basis and 19% of time seasonally. During high flows, fecal coliform exceeds thresholds 75% of the time. The source of the high bacteria levels is unknown at this time.
Date
11/12/2009