Impaired Water - Lake Koshkonong (Lake Koshkonong)
Dane, Jefferson, Rock County, Wisconsin
LR04, LR11
808700
10,595.67
Water is impaired due to one or more pollutants and associated quality impacts.
Notes
TP and/or chlorophyll data from the period 2006-2010 were insufficient to assess per 2012 WisCALM. However, the previous assessment(s) were carried forward, and the lake remains listed as impaired. TMDL is now approved.

Chlorophyll data were assessed during the 2020 listing cycle and confirm impairments.
Listing Details
Pollutant
Total Phosphorus
Listed For
Fish and Aquatic Life
Impairments
Low DO, Eutrophication
Current Use
Shallow Lowland Lake
Listing Status
TMDL Approved
Attainable Use
WWSF - Warmwater Sport Fishery
Priority
Not Applicable
Designated Use
WWSF - Warmwater Sport Fishery
303(d) ID
610
Listing Date
4/1/2002
Impaired Water Notes
TP and/or chlorophyll data from the period 2006-2010 were insufficient to assess per 2012 WisCALM. However, the previous assessment(s) were carried forward, and the lake remains listed as impaired.
Date
6/13/2011

Impaired Water Notes
Lake Koshkonong (808700) is a part of the Rock River Basin and is listed as impaired for total phosphorus and sediment/total suspended solids. 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 2020 listing cycle; chlorophyll sample data exceeded 2020 WisCALM listing thresholds for the Recreation use and Fish and Aquatic Life use.
Date
8/7/2019

 
Pollutant
Sediment/Total Suspended Solids
Listed For
Fish and Aquatic Life
Impairments
Degraded Habitat, Turbidity
Current Use
Shallow Lowland Lake
Listing Status
TMDL Approved
Attainable Use
WWSF - Warmwater Sport Fishery
Priority
Not Applicable
Designated Use
WWSF - Warmwater Sport Fishery
303(d) ID
610
Listing Date
4/1/2002
Impaired Water Notes
Lake Koshkonong (808700) is a part of the Rock River Basin and is listed as impaired for total phosphorus and sediment/total suspended solids. The Rock River Basin TMDLs for phosphorus and sediment were approved by the USEPA September 28, 2011.
Date
5/8/2012