Impaired Water - Lake Thompson (Thompson Lake)
Oneida County, Wisconsin
UW40
1569900
401.22
Proposed for removal from impaired waters during assessment period.
Notes
Thompson Lake was put on the 303(d) list due to mercury in 1998 and is proposed for removal in 2020 based on 2001 updated Fish Consumption advisories.

This lake was assessed for phosphorus and algae every two years between 2012 and 2020; in 2016 this lake was listed for excess algal growth and this impairment was confirmed in 2018. In 2020 algal levels were good and the listing was proposed for deletion.
Listing Details
Pollutant
Unknown Pollutant
Listed For
Impairments
Excess Algal Growth
Current Use
Listing Status
Delist
Attainable Use
Priority
Not Applicable
Designated Use
303(d) ID
2016-231
Listing Date
4/1/2016
Impaired Water Notes
This water was assessed during the 2016 listing cycle; chlorophyll sample data exceed 2016 WisCALM listing thresholds for the Recreation use, however, total phosphorus data do not exceed REC thresholds. Total phosphorus and chlorophyll data do not exceed Fish and Aquatic Life thresholds.
Date
8/7/2015

Impaired Water Notes
This water was assessed during the 2020 listing cycle; new chlorophyll sample data were clearly below 2020 WisCALM listing thresholds for the Recreation use and the Aquatic Life use.
Date
8/12/2019

 
Pollutant
Mercury
Listed For
Impairments
Mercury Contaminated Fish Tissue
Current Use
Listing Status
Delist
Attainable Use
Priority
Not Applicable
Designated Use
303(d) ID
485
Listing Date
4/1/1998
Impaired Water Notes
This listing was part of a set removed from the impaired waters list due to a change in fish consumption advisory levels in 2001. In 2001 Wisconsin DNR put into effect a statewide fish consumption advisory for mercury due to atmospheric deposition. Most of the lakes removed from the specific fish consumption advisories list in 2001 were not removed from the impaired waters list even though the thresholds had changed. For the 2020 assessment process WDNR requested delisting of 91 waters with residual mercury listings from prior to 2001. This request was approved by US EPA.
Date
9/4/2018