319 project funded - 2020 Mill Creek TP Monitoring for 9KE Plan


Wood County LCD and the Mill Creek Farmer-led Group are working to develop a 9KE Plan for the Mill Creek Watershed. This project is to support lab costs for baseline TP data at 6 points in the HUC 10 (Mill Creek HUC 0707000302) watershed. The County will find volunteers to collect samples. This will identify baseline TP data for the watershed, and help identify reduction goals for their watershed plan, as well as establish natural variability for the sites. This monitoring began in 2019, and this will be second year of monitoring TP concentrations in the watershed.


Collect baseline growing season median total phosphorous concentrations at six locations of the Mill Creek Watershed, for their nine key element plan. GSM monitoring began in 2019, this would be year two of anticipated three years of TP concentration data, to account for natural and climactic variability. Baseline water chemistry for 9 key element plan.


Baseline TP concentrations for county to help identify reduction goals, as well as natural baseline concentrations over three years, for 9-key element plan. Project will last three years to account for natural and climatic variability ending in October of 2021. Data will be managed in the SWIMS database.

Study Design

Growing season TP sampling at six locations in the Mill Creek watershed. Wood County will find volunteers to collect the water samples at the four pour points. Six samples will be collected per year during the growing season and will continue to be collected until the end of the growing season in 2021. Water chemistry sample sites at Robin Road, Cardinal Road, CTH PP, CTH O, CTH K, and CTH F(WBIC 1398600).

Related Reports

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Targeted Watershed Approach
Planning (WQ, Nine Key Element)
Reports and Documents
Data Documentation
The overall goal of this project is to evaluate the success of the Mead Lake TMDL and determine if additional TP load reductions are needed from the watershed. There are multiple objectives of this project. 1) Data collected will be used to determine if the installation of BMPs have reduced TP loading from the watershed and if water quality conditions improved in Mead Lake. The data will help evaluate the accuracy of the TP load reduction goal developed in the 2008 TMDL. The information may help in assessing new TP sources in the watershed. 2) Data collected will provide a baseline to document current water quality conditions and will allow for a comparison following additional BMP installation. This study will allow for an overall watershed and a site specific evaluation.
Mill Creek TWA 2020 Watershed Map (319 project-funded) (2022 WQMPLAN)
Mill Creek is a 47-mile tributary of the Wisconsin River. The stream originates in the City of Marshfield and has minimal stream flow in the upper reaches. The Marshfield WWTP discharges to the headwaters of Mill Creek and contributes more than 90% of the stream flow at the point of discharge. The upper 14 miles of the stream is listed in NR 104 as a Limited Aquatic Life variance stream and the lower 33 miles is classified as Fish and Aquatic life waters. Mill Creek is also listed as an impaired water body on EPA’s 303d list for low dissolved oxygen, which required the Department to develop a TMDL for the stream. The stream is impacted by storm water run-off from Marshfield, sedimentation, barnyard and cropland run-off, flashy stream flow, channel ditching, stream bank erosion, ammonia toxicity and nutrient enrichment. Large volumes of storm water scours streambeds erode streams banks, and carries sediment, nutrients, and other pollutants to surface waters. August 2000 HBI results suggest there is a significant organic loading to the stream. Water samples collected in the winter of 2000 (before the new treatment plant was built) found ammonia concentrations high enough to cause chronic toxicity to aquatic life based on EPA criteria. Since Mill Creek is currently classified as Limited Aquatic Life, the WWTP in Marshfield has no ammonia limit. This plan provides an overview of the physical characteristics of the Mill Creek watershed including land use and land management. The plan will also summarize the several environmental studies and programs that increased the understanding of the causes of water quality degradation, past conservation initiatives and investments aimed at reducing agricultural runoff, and program outcomes. The intent of the background information is to provide a historical perspective of water quality and quantity issues for the watershed which will serve as a basis for developing a long range plan for the river system. Success is achieved when the long term use of soil and water resources are balanced with the safety, health and prosperity of the community. At the time of the Mill Creek watershed plan submission (2019), the Total Maximum Daily Load (TMDL) plan for the Wisconsin River basin has been submitted to EPA for review and approval. Wood County acknowledges that the pollutant reduction goals and allocation limits developed to address the current resource concerns in both streams and flowages in the Mill Creek Watershed are forthcoming. Wood and Portage County also acknowledge that once the Wisconsin River Basin TMDL report is complete, this plan may need to be modified to be consistent with the TMDL report.
Activities & Recommendations
Nine Key Element Plan
Support of 9key plan