Impaired Water - Rock River (Rock River)
Rock County, Wisconsin
LR02, LR03
788800
171.08 - 183.45
12.37
Water is impaired due to one or more pollutants and associated quality impacts.
Notes
This segment of the Rock River was originally listed as impaired in 1998 for total phosphorus and total suspended solids. A TMDL is being developed.

This water was assessed during the 2012 listing cycle, and total phosphorus data exceed 2012 WisCALM listing criteria for the fish and aquatic life use.

This water was assessed during the 2014 listing cycle; total phosphorus sample data exceed 2014 WisCALM listing criteria for the Fish and Aquatic Life use and biological impairment was observed (i.e. at least one macroinvertebrate or fish Index of Biotic Integrity (IBI) scored in the poor condition category).

This water was assessed during the 2016 listing cycle; total phosphorus sample data exceeded 2016 WisCALM listing criteria for the Fish and Aquatic Life use and biological impairment was observed (i.e. at least one macroinvertebrate or fish Index of Biotic Integrity (IBI) scored in the poor condition category).

This water was assessed during the 2018 listing cycle; new total phosphorus sample data exceed 2018 WisCALM listing criteria for the Fish and Aquatic Life use, however, no biological data (i.e. no macroinvertebrate or fish Index of Biotic Integrity (IBI) scores) were available to assess biological impairment. New chloride sample data were clearly below 2018 WisCALM listing thresholds for the Fish and Aquatic Life use.
This water was assessed during the 2020 listing cycle; new total phosphorus sample data exceed 2020 WisCALM listing criteria for the Fish and Aquatic Life use and biological impairment was observed (i.e. at least one macroinvertebrate Index of Biotic Integrity (IBI) scored in the poor condition category).New chloride sample data were clearly below 2020 WisCALM listing thresholds for the Fish and Aquatic Life use.
Listing Details
Pollutant
Total Phosphorus
Listed For
Fish and Aquatic Life
Impairments
Low DO
Current Use
WWSF - Warmwater Sport Fishery
Listing Status
TMDL Approved
Attainable Use
WWSF - Warmwater Sport Fishery
Priority
Not Applicable
Designated Use
WWSF - Warmwater Sport Fishery
303(d) ID
401
Listing Date
4/1/1998
Impaired Water Notes
There are many lakes, rivers or streams in the Rock River Basin that are included on the 303(d) List. This effort is focused on those waters that are impaired by either excessive sediment, high phosphorus concentrations, or both sediment and phosphorus (see Table 1). These pollutants cause impacts to waterways which include low dissolved oxygen concentrations, degraded habitat, and excessive turbidity. All of these problems result in harm to fish and aquatic life, water quality, recreation and even navigation. Everyone who lives or recreates in the Rock River basin will benefit from the improved water quality that will result from reduced sediment and phosphorus.
Date
12/1/2006

Impaired Water Notes
The Rock River (788800, miles 171.1-304.9) is a part of the Rock River Basin and is listed as impaired for sediment/total suspended solids and total phosphorus. The Rock River Basin TMDLs for phosphorus and sediment were approved by the USEPA September 28, 2011.
Date
5/8/2012

Impaired Water Notes
This water was assessed during the 2014 listing cycle; total phosphorus sample data exceed 2014 WisCALM listing criteria for the Fish and Aquatic Life use, however, available biological data do not indicate impairment (i.e. no macroinvertebrate or fish Index of Biotic Integrity (IBI) scored in the "poor" condition category).
Date
4/1/2014

Impaired Water Notes
This water was assessed during the 2016 listing cycle; total phosphorus sample data exceed 2016 WisCALM listing criteria for the Fish and Aquatic Life use, however, no biological data (i.e. no macroinvertebrate or fish Index of Biotic Integrity (IBI) scores) were available to assess biological impairment.
Date
10/7/2015

Impaired Water Notes
This water was assessed during the 2018 listing cycle; new total phosphorus sample data exceed 2018 WisCALM listing criteria for the Fish and Aquatic Life use, however, no biological data (i.e. no macroinvertebrate or fish Index of Biotic Integrity (IBI) scores) were available to assess biological impairment.
Date
4/18/2017

Impaired Water Notes
This water was assessed during the 2020 listing cycle; new total phosphorus sample data exceed 2020 WisCALM listing criteria for the Fish and Aquatic Life use and biological impairment was observed (i.e. at least one macroinvertebrate Index of Biotic Integrity (IBI) scored in the poor condition category).New chloride sample data were clearly below 2020 WisCALM listing thresholds for the Fish and Aquatic Life use.
Date
6/17/2019

 
Pollutant
PCBs
Listed For
Impairments
PCBs Contaminated Fish Tissue
Current Use
Listing Status
Pollutant Removed
Attainable Use
Priority
Delisted 2008
Designated Use
303(d) ID
401
Listing Date
4/1/1998
 
Pollutant
Mercury
Listed For
Impairments
Mercury Contaminated Fish Tissue
Current Use
Listing Status
Pollutant Removed
Attainable Use
Priority
Delisted 2008
Designated Use
303(d) ID
401
Listing Date
4/1/1998
Impaired Water Notes
Delisted in 2006 but not documented until 2008
Date
4/1/2008

 
Pollutant
Sediment/Total Suspended Solids
Listed For
Fish and Aquatic Life
Impairments
Degraded Habitat
Current Use
WWSF - Warmwater Sport Fishery
Listing Status
TMDL Approved
Attainable Use
WWSF - Warmwater Sport Fishery
Priority
Not Applicable
Designated Use
WWSF - Warmwater Sport Fishery
303(d) ID
401
Listing Date
4/1/1998
Impaired Water Notes
There are many lakes, rivers or streams in the Rock River Basin that are included on the
303(d) List. This effort is focused on those waters that are impaired by either excessive
sediment, high phosphorus concentrations, or both sediment and phosphorus (see Table 1).
These pollutants cause impacts to waterways which include low dissolved oxygen
concentrations, degraded habitat, and excessive turbidity. All of these problems result in
harm to fish and aquatic life, water quality, recreation and even navigation. Everyone who
lives or recreates in the Rock River basin will benefit from the improved water quality that will
result from reduced sediment and phosphorus
Date
12/1/2006

Impaired Water Notes
The Rock River (788800, miles 171.1-304.9) is a part of the Rock River Basin and is listed as impaired for sediment/total suspended solids and total phosphorus. The Rock River Basin TMDLs for phosphorus and sediment were approved by the USEPA September 28, 2011.
Date
5/8/2012