Waukesha County, Wisconsin
UR09
851100
0.00 - 4.11
4.11
Water is impaired due to one or more pollutants and associated quality impacts.
Notes
On 303d list. Also on 2002 trout streams list. This segment of Mason Creek has been listed on the state's 303d impaired water list since 1998 for Total Suspended Solids and Total Phosphorus. Included in the Rock River TMDL approved in September 2011.
This water was assessed every two-year cycle from 2018 to 2024; temperature levels were too high, confirming the elevated temperature impairment. Evaluations of chloride, bugs, and fish found good conditions.Pollutant
Sediment/Total Suspended Solids
Listed For
Fish and Aquatic Life
Impairments
Elevated Water Temperature, Degraded Habitat
Current Use
Unsupported Aquatic Life
Listing Status
TMDL Approved
Attainable Use
Coldwater - natural reproduction
Priority
Not Applicable
Designated Use
Coldwater - natural reproduction
303(d) ID
270
Listing Date
4/1/1998
Impaired Water Notes
Mason Creek (851100, miles 0-6.14) 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 2018 listing cycle; new temperature sample data exceed 2018 WisCALM listing criteria for the Fish and Aquatic Life use.
Date
4/12/2017
Impaired Water Notes
This water was assessed during the 2020 listing cycle; temperature sample data exceed 2020 WisCALM listing criteria for the Fish and Aquatic Life use. Based on the most updated information, no change in existing impaired waters listing is needed.
Date
6/14/2019
Pollutant
Total Phosphorus
Listed For
Fish and Aquatic Life
Impairments
Low DO
Current Use
Unsupported Aquatic Life
Listing Status
TMDL Approved
Attainable Use
Coldwater - natural reproduction
Priority
Not Applicable
Designated Use
Coldwater - natural reproduction
303(d) ID
270
Listing Date
4/1/1998
Impaired Water Notes
Mason Creek (851100, miles 0-6.14) 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