Impaired Water - Rock Dam Lake (Rock Dam Lake)
Clark County, Wisconsin
LC16
2139000
95.87
Water is impaired due to one or more pollutants and associated quality impacts.
Notes
Rock Dam Lake is on 303(d) list due to mercury, listed in 1998, and is proposed for removal based on 2001 updated Fish Consumption advisories.

This water was assessed for total phosphorus and chlorophyll-a in 2014, 2016, and 2018. An impairment by phosphorus was found each cycle.

This lake is covered by a restoration plan: Healthy Soils and Healthy Waters: A Community Strategy for the Eau Claire River Watershed (expires 2027).
Listing Details
Pollutant
Total Phosphorus
Listed For
Recreation
Impairments
Impairment Unknown
Current Use
Restricted Recreation
Listing Status
303d Listed
Attainable Use
Full Body Contact - Swimming, Boating
Priority
Low
Designated Use
Full Body Contact - Swimming, Boating
303(d) ID
2014-275
Listing Date
4/1/2014
Impaired Water Notes
This water was assessed during the 2018 listing cycle; total phosphorus sample data exceed 2018 WisCALM listing thresholds for the Recreation use and Fish and Aquatic Life use, however chlorophyll data do not exceed REC or FAL thresholds.
Date
7/11/2017

Impaired Water Notes
This water was assessed during the 2014 listing cycle; total phosphorus sample data 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.
Date
1/13/2014

Impaired Water Notes
This water was assessed during the 2016 listing cycle; total phosphorus sample data exceeded 2016 WisCALM listing thresholds for the Recreation, however, chlorophyll data do not exceed REC thresholds. Total phosphorus and chlorophyll data clearly met thresholds for Fish and Aquatic Life use.
Date
10/16/2015

Impaired Water Notes
This lake is covered by a restoration plan: Healthy Soils and Healthy Waters: A Community Strategy for the Eau Claire River Watershed (2027).
Date
7/24/2019

 
Pollutant
Mercury
Listed For
Impairments
NA
Current Use
Listing Status
Pollutant Removed
Attainable Use
Priority
Delisted 2020
Designated Use
303(d) ID
391
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