Walworth County, Wisconsin
FX05
753800
154.64
Water is impaired due to one or more pollutants and associated quality impacts.
Notes
This lake was listed in 2010. This water was assessed during the 2014 listing cycle; total phosphorus sample data overwhelmingly exceed 2014 WisCALM listing thresholds for the Recreation use, however, chlorophyll data do not exceed REC thresholds. Total phosphorus and chlorophyll data do not exceed Fish and Aquatic Life thresholds.Pollutant
Total Phosphorus
Listed For
Recreation
Impairments
High Phosphorus Levels
Current Use
Restricted Recreation
Listing Status
TMDL Development
Attainable Use
Recreation
Priority
High
Designated Use
Recreation
303(d) ID
2010-9
Listing Date
4/1/2010
Impaired Water Notes
Potter Lake should be considered impaired based on very high phosphorus levels, eutrophication, and degraded habitat due to minimal aquatic macrophytes. The Average Total Phosphorus concentration for Potter Lake (2004-2007) is .114 mg/l, which greatly exceeds the TP impairment threshold of .02 mg/l for Deep Seepage lakes. Although average TSI based on chlorophyll a is 56, which is 'Fair' for Deep Seepage lakes, per Heidi Bunk this lake should be considered impaired. A number of whole lake treatments were done with Sonar pesticides in 1997, 2004, and 2005, which due to the unselective nature of the treatment decimated the macrophyte population. In Fall 2005 a team did a macrophyte survey & found only two individual plants. Heidi Bunk visited in fall 2008 & there were some macrophytes present, but minimal. In 1992 macrophyte rooting depth was 15 ft; in 2007 and 2008 it was 9.5 ft, indicating a significant decrease in total area of macrophyte coverage & habitat. It is not meeting its fish and aquatic life use. Most of the lake is 8 ft deep or less (much of it is less than 4 feet), with one small deep hole approximately 25 feet deep. Nonpoint sources are the primary contributors to Potter Lake. The watershed is 545 acres, and its land uses are Residential 37%, Agricultural 20%, transportation 6.5%, Woodlands 4%, minimal commercial/industrial. Recommendations for additional monitoring include more DO profiles, and Bunk recommends management to add macrophytes (there is a tentative plan in place for the west side of the lake).
Date
10/18/2009
Impaired Water Notes
TP and/or chlorophyll data from the period 2006-2010 were insufficient to assess per 2012 WisCALM. However, the previous assessment(s) were carried forward, and the lake remains listed as impaired.
Date
6/14/2011
Impaired Water Notes
This water was assessed during the 2014 listing cycle; total phosphorus sample data overwhelmingly exceed 2014 WisCALM listing thresholds for the Recreation use, however, chlorophyll data do not exceed REC thresholds. Total phosphorus and chlorophyll data do not exceed Fish and Aquatic Life thresholds. The impairment of 'Eutrophication' should be removed.
Date
1/20/2014