Wood County, Wisconsin
CW05
1369900
286.71
Water is impaired due to one or more pollutants and associated quality impacts.
Notes
Dexter Lake has been listed for E. Coli since 1998. This lake was evaluated for phosphorus and algae every two years from 2008 to 2020. In 2010 Dexter Lake was listed for phosphorus and algae.Pollutant
Total Phosphorus
Listed For
Recreation
Impairments
Excess Algal Growth, Eutrophication
Current Use
Restricted Recreation
Listing Status
303d Listed
Attainable Use
Recreation
Priority
Low
Designated Use
Recreation
303(d) ID
2010-11
Listing Date
4/1/2010
Impaired Water Notes
In-lake water quality data was collected by DNR staff in 2006, 2008 and 2009. In 2006 and 2009, the total phosphorus (TP) data meet the minimum data requirements and clearly exceed the listing criteria by an order of magnitude. Using the standard calculation, average TP is .396 mg/l, which exceeds the listing threshold of .04 mgl/l, and TP should thus be listed as a pollutant. For these two years, Growing Season Epilimnetic (GSE) TP Averages exceed the listing threshold of .04 mg/l, as shown below.
Year GSE Ave. Listing threshold
2006 418 ug/l (.418 mg/l) .04 mg/l
2009* 393 ug/L (.393 mg/L)
2008** 341 ug/l (.341 mg/l)
* Some 2009 samples are not yet back from the lab but it is expected these samples will be consistent with values previously collected, or higher. The number of samples we currently have for 2009 do meet minimum data requirements for listing.
**2008 only has 2 data points instead of the required 3 data points for listing, but those two values showed a similar pattern to those collected in 2006 and 2009.
Additional Trophic State Index (TSI) information:
· The average summer TSI value based on chlorophyll a was 67.3, which does not exceed the listing threshold of 71 prescribed in the WisCALM (2010), but did flag the water as ‘Fair’ for further review, leading to analysis of the high TP levels. Chl-a TSI may be below 71 because the naturally stained water and low hydraulic residence time would limit some algal growth even though the P levels are extremely high.
· Ave. summer TSI based on Secchi Disk clarity is 73.1, which exceeds the threshold for TSI-SD of 71 for a Poor general assessment (TSI-SD is used only for general assessment and not for 303(d) listing). Secchi disk TSI's are high even though the chl-a levels were lower, some of which may be attributed to the stained water.
Date
10/21/2009
Impaired Water Notes
Lake Dexter is a shallow impoundment on the Yellow River Beaver Creek about 3 miles downstream of the City of Pittsville. Lake Dexter has poor water clarity with an summer average Secchi Disk of about 1.2 feet and significant algae blooms during low flow conditions that can create very low DO levels. Although the TSI-chlorophyll for this water flagged it as 'Fair' rather than 'Poor', the average total phosphorus is very high at .396 mg/l, which exceeds the listing threshold of .04 mgl/l by an order of magnitude. In the best professional judgment of the biologist this waterbody is impaired; Chl-a TSI is 67.3, which is below the impairment threshold of 71 but may be because the naturally stained water and low hydraulic residence time would limit some algal growth even though the P levels are extremely high.
Date
10/21/2009
Impaired Water Notes
This water was assessed during the 2012 listing cycle, and total phosphorus sample data exceed 2012 WisCALM listing criteria for the fish and aquatic life and recreation uses. Chlorophyll data from the period 2006-2010 were insufficient to assess per 2012 WisCALM.
Date
6/15/2011
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 only exceeds REC thresholds.
Date
3/24/2014
Impaired Water Notes
This water was assessed during the 2016 listing cycle; total phosphorus sample data overwhelmingly exceeded 2016 WisCALM listing thresholds for the Recreation use and Fish and Aquatic Life use, and chlorophyll data exceeded only REC thresholds.
Date
10/12/2015
Impaired Water Notes
This water was assessed during the 2020 listing cycle; total phosphorus and chlorophyll sample data exceeded 2020 WisCALM listing thresholds for the Recreation use and Fish and Aquatic Life use.
Date
7/10/2019
Pollutant
E. coli
Listed For
Recreation
Impairments
Recreational Restrictions - Pathogens
Current Use
Restricted Recreation
Listing Status
303d Listed
Attainable Use
Recreation
Priority
Low
Designated Use
Recreation
303(d) ID
673
Listing Date
4/1/1998
Impaired Water Notes
Additional pollutants and impairments were recommended to be added in 2008, but only one year of data (2006) exist. Three years of monitoring data are needed. K. Voss
Date
4/1/2008