Impaired Water - Lac Courte Oreilles (Musky Bay)
Sawyer County, Wisconsin
UC20
2390800
301.77
Proposed for removal from impaired waters during assessment period.
Notes
This water was assessed during the 2012 listing cycle. Total phosphorus concentrations exceed WisCALM listing thresholds for recreation use for shallow lowland drainge lakes (threshold applies to the bay). Observed macrophyte density in Musky Bay is not representative of expected conditions and is in fact causing an impairment of the recreational use.

We recommend delisting Musky Bay from the impaired waters list. In 2012, when Musky Bay was listed for high curly-leaf pondweed abundance with phosphorus as the pollutant, both TP and the plant metrics indicated that the lake was impaired. Now, at 29.53 ug/L, TP clearly attains the criterion of 40 ug/L. Treatment for curly-leaf pondweed has been effective in reducing its presence. Chlorophyll a attains both the recreation and aquatic life thresholds, and aquatic plants indicate that Musky Bay is in good condition.
Listing Details
Pollutant
Total Phosphorus
Listed For
Impairments
Non-Native Aquatic Plants
Current Use
Listing Status
Delist
Attainable Use
Priority
Not Applicable
Designated Use
303(d) ID
2012-MB
Listing Date
4/1/2012
Impaired Water Notes
This water was assessed during the 2012 listing cycle. Total phosphorus concentrations exceed WisCALM listing thresholds for recreation use for shallow lowland drainge lakes (threshold applies to the bay). Observed macrophyte density in Musky Bay is not representative of expected conditions and is in fact causing an impairment of the recreational use.
Date
4/1/2012

Impaired Water Notes
"We recommend delisting Musky Bay from the impaired waters list. In 2012, when Musky Bay was listed for high curly-leaf pondweed abundance with phosphorus as the pollutant, both TP and the plant metrics indicated that the lake was impaired. Now, at 29.53 ug/L, TP clearly attains the criterion of 40 ug/L. Treatment for curly-leaf pondweed has been effective in reducing its presence. Chlorophyll a attains both the recreation and aquatic life thresholds, and aquatic plants indicate that Musky Bay is in good condition." Page 64, 7.5 SSC Recommendation for Musky Bay (2018).
Date
4/22/2019