Iowa County, Wisconsin
LW11
1239400
212.50
Water is impaired due to one or more pollutants and associated quality impacts.
Notes
Blackhawk Lake was evaluated every two-year cycle from 2012 to 2024; in the 2016 cycle excess algal growth was identified and in the 2022 elevated phosphorus was also identified. This lake is on the Impaired Waters List.Pollutant
Unknown Pollutant
Listed For
Recreation
Impairments
Excess Algal Growth
Current Use
Restricted Recreation
Listing Status
303d Listed
Attainable Use
Recreation
Priority
Low
Designated Use
Recreation
303(d) ID
2024-01
Listing Date
4/1/2024
Impaired Water Notes
This water was assessed during the 2018 listing cycle; new chlorophyll sample data exceeded 2018 WisCALM listing thresholds for the Recreation use.
Date
7/12/2017
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; chlorophyll sample data exceeded 2020 WisCALM listing thresholds for the Recreation use. Based on the most updated information, no change in existing impaired waters listing is needed.
Date
6/11/2019
Impaired Water Notes
Phosphorus was identified as the cause of excess algal growth. This unknown is proposed for delisting.
Date
6/14/2021
Pollutant
Total Phosphorus
Listed For
Recreation
Impairments
Impairment Unknown, Excess Algal Growth
Current Use
Restricted Recreation
Listing Status
Pollutant Removed
Attainable Use
Recreation
Priority
Delisted 2024
Designated Use
Recreation
303(d) ID
2022-037
Listing Date
4/1/2022
Impaired Water Notes
This water was assessed during the 2022 cycle; new phosphorus sample data nearly exceeded 2022 WisCALM listing criteria for Aquatic Life and Recreation use. Based on elevated algal growth and BGA blooms after mid July, the biologist recommended this water be listed for phosphorus as well.
Date
6/14/2021