Impaired Water - Blackhawk Lake (Blackhawk Lake)
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 2022; 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.
Listing Details
Pollutant
Total Phosphorus
Listed For
Recreation
Impairments
Impairment Unknown, Excess Algal Growth
Current Use
Restricted Recreation
Listing Status
Addition
Attainable Use
Full Body Contact - Swimming, Boating
Priority
Low
Designated Use
Full Body Contact - Swimming, Boating
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

 
Pollutant
Unknown Pollutant
Listed For
Recreation
Impairments
Excess Algal Growth
Current Use
Restricted Recreation
Listing Status
Deletion
Attainable Use
Full Body Contact - Swimming, Boating
Priority
Not Applicable
Designated Use
Full Body Contact - Swimming, Boating
303(d) ID
2016-223
Listing Date
4/1/2016
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