Impaired Water - Castle Rock Lake (Castle Rock Flowage)
Adams, Juneau County, Wisconsin
CW01, CW02, CW06
1345700
12,385.67
Water is impaired due to one or more pollutants and associated quality impacts.
Notes
Castle Rock Flowage was evaluated in 1998 at which time contaminated sediment was found with PCBs, Mercury, and Dioxins. High water column phosphorus levels were also found. Cleanup projects in the lake resulted the removal of contaminated sediment and delistings for PCBs, Mercury, and Dioxins. The high phosphorus levels have remained, observed in 2014, 2016, and 2018. The phosphorus listing is part of the Wisconsin River TMDL, a restoration plan approved by the EPA in April 2019.
Listing Details
Pollutant
Total Phosphorus
Listed For
Recreation
Impairments
Eutrophication, High Phosphorus Levels
Current Use
Restricted Recreation
Listing Status
TMDL Approved
Attainable Use
Full Body Contact - Swimming, Boating
Priority
Not Applicable
Designated Use
Full Body Contact - Swimming, Boating
303(d) ID
534
Listing Date
4/1/1998
Impaired Water Notes
Total nitrogen was removed from this water as this listing was in error. This should have been removed in 2008. Original listing may have been nutrients and when switching over N was accidentally chosen instead of TP as pollutant.
Date
3/17/2011

Impaired Water Notes
Jim Kreitlow (NOR) documented dissolved oxygen standards violations while sampling the lake in the mid 1990s. Dissolved oxygen concentrations below 5 mg/l were generally found during the early morning hours, probably a result of algae respiration.

The cause of this impairment is likely a result of excessive nutrient loading (phosphorus) from point and nonpoint sources in the watershed. As a result, the flowage is very eutrophic with abundant algae growth.

The Petenwell and Castle Rock Flowages Comprehensive Management Plan was completed in 1996. This report indicates severe algal blooms cause periodic shifts in dissolved oxygen. During photosynthesis, dissolved oxygen values are high (11-12 mg/l) but during respiration, they can drop below 5.0 mg/l (STORET, 1992 was referenced). The report also indicates blue-green algae are the dominant phytoplankton in the Petenwell and Castle Rock Flowages. The report mentions that sediment sampling was completed in both flowages, but additional sampling was recommended. Previous sampling found high levels of 2,3,7,8-TCDD and 2,3,7,8-TCDF in the sediments. PCBs and mercury have also been detected at a limited number of sampling sites. Currently, a specific fish consumption advisory exists on the flowage for dioxin.
Date
4/8/2010

Impaired Water Notes
Needs monitoring. Data documentation sheet did not include phosphorus so only total nitrogen was included from the 2002 data documentation sheet.
Date
4/1/2008

Impaired Water Notes
This water was assessed during the 2014 listing cycle; total phosphorus sample data overwhelmingly exceed 2014 WisCALM listing thresholds for the Recreation use and exceeded Fish and Aquatic Life use, however, chlorophyll data do not exceed REC or FAL thresholds.
Date
1/20/2014

Impaired Water Notes
This water was assessed during the 2016 listing cycle; total phosphorus sample data overwhelmingly exceed 2016 WisCALM listing thresholds for the Recreation use and exceeded Fish and Aquatic Life use, however, chlorophyll data do not exceed REC or FAL thresholds.
Date
8/19/2015

Impaired Water Notes
This water is part of the 2019 approved Wisconsin River TMDL addressing Total Phosphorus and Total Suspended Solids.
Date
6/10/2019

 
Pollutant
Dioxin
Listed For
Impairments
NA
Current Use
Listing Status
Pollutant Removed
Attainable Use
Priority
Delisted 2016
Designated Use
303(d) ID
534
Listing Date
4/1/1998
Impaired Water Notes
Sampling has found high levels of 2,3,7,8-TCDD and 2,3,7,8-TCDF in the sediments. PCBs and mercury have also been detected at limited sampling sites. However there is no specific advice for PCBs and mercury but Castlerock Flowage has specific fish advice for the Wisconsin River from Petenwell Dam downstream to Castle Rock Dam (Castle Rock Flowage) for Carp for dioxin.
Date
10/13/2010

Impaired Water Notes
This water was assessed during the 2016 listing cycle; new fish tissue data indicates that this waterbody should be removed from the impaired waters list for Dioxins.
Date
8/19/2015

 
Pollutant
PCBs
Listed For
Impairments
NA
Current Use
Listing Status
Pollutant Removed
Attainable Use
Priority
Delisted 2008
Designated Use
303(d) ID
534
Listing Date
4/1/1998
Impaired Water Notes
2008 303d list proposed delist for Mercury and PCBs only.
Date
4/1/2008

 
Pollutant
Mercury
Listed For
Impairments
NA
Current Use
Listing Status
Pollutant Removed
Attainable Use
Priority
Delisted 2008
Designated Use
303(d) ID
534
Listing Date
4/1/1998
Impaired Water Notes
Castlerock Flowage has specific fish advice for the Wisconsin River from Petenwell Dam downstream to Castle Rock Dam (Castle Rock Flowage) for
Carp All sizes for dioxin.
Date
12/19/2010

Impaired Water Notes
Waterbody ID Code (WBIC): 1345700
County(ies): Adams, Juneau
Impaired Stream Reach (location and mileage):
Entire Flowage (15 miles) - River miles 159.7-174.8
Dissolved oxygen, pH violations, FCA, Hg, PCB, Dioxin
Cause of impairment -- Nutrients, contaminated sediment
- Point and nonpoint sources

Jim Kreitlow (NOR) documented dissolved oxygen standards violations while sampling the lake in the mid 1990s. Dissolved oxygen concentrations below 5 mg/l were generally found during the early morning hours, probably a result of algae respiration. Values for pH above 9.0 were documented in 1994, 1995, 1996 and 1997 (9 of 107 samples).

The cause of this impairment is likely a result of excessive nutrient loading (phosphorus) from point and nonpoint sources in the watershed. As a result, the flowage is very eutrophic with abundant algae growth.

The Petenwell and Castle Rock Flowages Comprehensive Management Plan was completed in 1996. This report indicates severe algal blooms cause periodic shifts in dissolved oxygen. During photosynthesis, dissolved oxygen values are high (11-12 mg/l) but during respiration, they can drop below 5.0 mg/l (Storet, 1992 was referenced). The report also indicates blue-green algae are the dominant phytoplankton in the Petenwell and Castle Rock Flowages. The report also references sediment sampling has been completed in both flowages, however additional sampling is recommended. Previous sampling found high levels of 2,3,7,8-TCDD and 2,3,7,8-TCDF in the sediments. PCBs and mercury have also been detected at limited sampling sites. Currently, a fish consumption advisory exists on the flowage for PCBs, dioxin and mercury.
Date
4/1/2002

Impaired Water Notes
2008 303d list proposed delist for Mercury and PCB's only.
Date
4/1/2008