Phosphorus Compliance – Badger Mill Creek

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The District’s work to find a phosphorus compliance solution for Badger Mill Creek

Excess phosphorus is harming Wisconsin waters, making water quality standards increasingly restrictive. The Wisconsin Department of Natural Resources (WDNR) enforces these standards through the federal Clean Water Act and the state’s Phosphorus Rule, established on December 1, 2010. These rules set maximum thresholds for phosphorus in Wisconsin’s surface waters and set procedures through permits designed to help curb the growing issue.  Due to Phosphorus Rule requirements, Madison Metropolitan Sewerage District spent several years developing a set of compliance options for Badger Mill Creek, one of our discharge streams.

What is Project PLUS?

Project PLUS (Phosphorus Limits & Updated Solutions) reflects our work in 2022 and 2023 to determine a final phosphorus compliance solution for Badger Mill Creek.

 Through technical assessments, community engagement and ongoing partner conversations, PLUS had three goals: 

  • Achieve phosphorus compliance standards.
  • Minimize harm to the biology of the stream.
  • Maintain fiscal responsibility to ratepayers and owner communities.

At its May 25, 2023 meeting, the District’s Commission approved, via resolution, the discontinuance of effluent, or cleaned wastewater, to the Badger Mill Creek to meet its permit requirement for phosphorus compliance in that waterway. This compliance solution is now moving through a regulatory process, which could take a year or more.

The Commission also approved $1 million in projects to support the health and resiliency of Badger Mill Creek and formed a stakeholder group to develop a portfolio of projects.

FAQs On Phosphorus and Project PLUS

About Phosphorus

What is phosphorus? Is it bad?

Phosphorus is an essential nutrient for plant and animal growth. 

However, excess phosphorus will encourage undesirable plants and algae to grow sometimes causing algae blooms that can reduce recreational use and property values, create problems in our waterways and drinking water and impact public health.    

Where does phosphorus come from?

Excess phosphorus can come from our yards via fertilizer or yard waste, agriculture run-off, cleaning products, septic systems, appliances, pets and domestic wastewater (i.e. from our diets, household products). 

Why is Madison Metropolitan Sewerage District concerned about phosphorus?

When wastewater enters a wastewater treatment plant, the amount of phosphorus must be reduced to prevent excess phosphorous in the discharge that can be harmful to waterways. The District’s wastewater treatment plant discharges and drains into local rivers and streams that flow into the Mississippi River before moving to the Gulf of Mexico. When in excess, nutrients like phosphorus accumulate and become harmful pollutants for people, aquatic life and watershed environments.  

 Because of this, the Wisconsin Department of Natural Resources requires all wastewater treatment plants to meet specific standards for the amount of phosphorus in their discharges per the federal Clean Water Act and Wisconsin’s Phosphorus Rule.   

Does the District remove or recycle phosphorus?

Madison Metropolitan Sewerage District removes over 96% of the phosphorus from incoming wastewater. In addition, the District removes this phosphorus through phosphorus harvesting technology, the Yahara WINS adaptive management project​, community awareness campaigns and pollution prevention education​, and most recently with the initiation of Project PLUS at Badger Mill Creek. The district also manages phosphorus on the landscape with improved application techniques for biosolids that are recycled on area farm fields.  

Project PLUS

What is Badger Mill Creek Project PLUS?

To comply with the District’s Wisconsin Pollutant Discharge Elimination System (WPDES) permit, the District must achieve phosphorus compliance in Badger Mill Creek, a stream in which the District discharges treated wastewater.  Badger Mill Creek PLUS (Phosphorus Limits & Updated Solutions) is the initiative supporting compliance. Project PLUS will help identify a phosphorus compliance recommendation.  

Who is involved in Project PLUS?

Various experts and individuals assisted on Project PLUS, including District staff, WDNR, U.S. Geological Survey scientists and technical staff and engineering/environmental experts. In addition, the District continues to have conversations with community partners and stakeholder groups. As a result, the District presented a solution that aligns with the collective team’s scientific feedback, data, project goals and shared community interests for achieving phosphorus compliance in Badger Mill Creek.    

How is Project PLUS different than Yahara WINS?

The Yahara Watershed Improvement Network, known as Yahara WINS, is a groundbreaking initiative to achieve clean water goals, reduce phosphorus loads and meet more stringent water quality standards in the Rock River Basin. With Yahara WINS, a reduction from all watershed sources (agricultural and urban stormwater runoff) is required to address impairments caused by phosphorus and total suspended solids. Compared to Badger Mill Creek, the initiative has many different factors contributing to its design. 

One significant difference for Yahara WINS is the Total Maximum Daily Load (TMDL) assessment conducted by Wisconsin DNR and approved by U.S. EPA. The TMDL provides a roadmap for the reductions needed to meet Wisconsin’s water quality standards, including specific regulatory requirements and the identification of responsible entities. The TMDL also triggers a regulatory requirement that point sources must reduce runoff to meet surface water standards.  

Without a regulatory driver, such as a TMDL for Badger Mill Creek, the District is the only required agency to contribute resources and lead phosphorus reduction activities. With the District as the only regulated entity required to pay for phosphorus reductions, there is a significant difference in the number of pounds of phosphorus that need to be reduced to reach water quality goals compared to other options being considered. 

When faced with a choice to meet regulatory requirements alone or collectively, in the case of Yahara WINS, point sources chose to pool resources and work collaboratively. Along with non-point sources like agricultural producers and land conservation agencies, Yahara WINS partners work together to aim to reduce runoff in the watershed to improve water quality and meet required regulations.  

In addition, a 20-year commitment from a significant geographic span of landowners would need to be obtained to apply adaptive management practices for reducing excess phosphorus in Badger Mill Creek. This only adds to the challenge of meeting water quality standards without a regulatory driver. 

Studies and Assessments

What compliance solutions were considered?

In June 2022, we presented preliminary compliance alternatives to the Commission, including watershed adaptive management, modification of the flow, water quality trading, site-specific criterion, variance and tertiary treatment.  

In October 2022, District staff reported to the Commission that adaptive management and water quality trading were losing viability as options and that tertiary treatment, originally one of the six options, would be reconsidered. 

A Final Alternatives Assessment for Phosphorus Compliance Report delivered in April 2023 considered four remaining phosphorus compliance options: diversion, water quality trading, watershed adaptive management and tertiary treatment. 

What types of answers did District assessments provide?

The District hired consulting firms to complete two studies to help inform a final compliance recommendation.  

The first study focused on understanding the influence of the District’s treated effluent on the stream flow, depth and habitat. To do this, we focused on answering two key questions:   

1. What is the depth and flow of the stream with and without the treated effluent discharge?  
2. What is the impact of any changes in depth and flow on in-stream habitat?   

The second study focused on an engineering feasibility assessment to critically examine tertiary treatment options at the Nine Springs Wastewater Treatment Plant. It provided the District with hydraulic and pumping information, operations and management of the system, a construction footprint, cost information and energy use of a tertiary treatment system. These answers are provided within the engineering feasibility report and included in the final alternative assessment report available to the public.  

Badger Mill Creek Phosphorus Compliance Preliminary Engineering Feasibility Report 
Badger Mill Creek Hydrologic Assessment, Emmons & Oliver Resources, Inc. 
Final Alternatives Assessment for Phosphorus Compliance Report 

How did the District assess the impact of effluent on streamflow and stream habitat?

With WDNR guidance and consultant assistance, the team began flow and habitat measurements at various site locations along Badger Mill Creek and the Sugar River in January 2023.   

The assessments occurred under two scenarios.   

  • Scenario 1: District effluent being discharged as normal per the District’s permit  
  • Scenario 2: District effluent not being discharged  

The before-and-after study design allowed the District to understand the impact of the effluent flow on the stream under current climatological and hydraulic conditions. In consultation with the DNR and using historic USGS hydrograph data, this specific assessment’s timeline aligned with the winter months. This was done to understand the impact of treated effluent on the stream when flow and depth are historically at their lowest.  

Why was it necessary to turn off the District’s flow to Badger Mill Creek?

The District is committed to minimizing harm to the biology in Badger Mill Creek. The District undertook a study to examine the potential impacts discontinuing effluent flow to Badger Mill Creek. Done in consultation with WDNR and experts throughout the region, this test involved slowly reducing flow and then maintaining zero flow for approximately 2.5 months between January and April 2023.

During this period, we assessed flow, depths and habitat and asked interested parties to observe daily conditions in the stream. Hundreds of observations were received by the District showcasing the daily differences along the stream. Most importantly, these observations demonstrated that flow remained in all segments of the stream throughout the test period. These visual observations were further supported by stream measurements taken at various sites on Badger Mill Creek down to the confluence with the Sugar River.

We specifically conducted this study during the low-flow months as this is when the creek’s historic hydrograph (a measure of water flow over time) is at its lowest. This allowed us to directly examine the impact the District effluent has on streamflow, depth and habitat at the times when the stream would have the lowest natural flow in order to understand stream conditions under the worst-case scenario.

How has the District worked with WDNR on the project? What advice has WDNR offered regarding the assessment period?

From the project’s start, the District has worked closely with WDNR to develop and vet our habitat and flow assessment process. The WDNR consulted with the District on study design elements around the District’s approach of a single-season test period during winter low-flow conditions. 

In consultation with WDNR, it was communicated that a short-term winter study would be sufficient to assess changes to flow, temperature and stream physical characteristics like habitat. 

How did the community get involved with creek observations and data reporting during the winter 2023 assessment phase?

The District created a digital report form to allow interested parties to engage with a consultant-led assessment of Badger Mill Creek. We asked interested citizen scientists to record observations of their favorite area(s) of Badger Mill Creek and/or the Sugar River through February 2023. 

However, the data shared through the report form is not part of a specific scientific study protocol. Therefore, while the observations were helpful as another way understand what is happening in the stream, the observations were not used to determine a final recommendation. 

What reports and scientific findings are available for review? How have you shared this information?

Summaries of the stream flow and treatment engineering studies are available below. 

Badger Mill Creek Phosphorus Compliance Preliminary Engineering Feasibility Report 
Badger Mill Creek Hydrologic Assessment, Emmons & Oliver Resources, Inc. 

A Final Alternatives Assessment for Phosphorus Compliance Report delivered in April 2023 considered four remaining phosphorus compliance options: diversion, water quality trading, watershed adaptive management and tertiary treatment. 

In addition, project updates are shared on this dedicated project web page and with owner communities and Commission members. In addition, social media, email communications and working with local media sources are used as a companion to regular outreach.  


What has the District recommended to meet phosphorus compliance in Badger Mill Creek?

On April 27, the District presented a phosphorus compliance solution for Badger Mill Creek to its Commission.  
The recommendation comprises a two-part strategy involving discontinuing District effluent to Badger Mill Creek and providing financial resources to enhance the stream corridor. This solution will help protect our waterways from the harmful impacts of excess phosphorus and provide an opportunity for community ownership and involvement in enhancing the creek. 

The recommendation presentation is available on YouTube, and the Final Alternatives Assessment for Phosphorus Compliance Report is accessible for public review.  

Is it possible your recommendation will create changes in Badger Mill Creek?

The District has a shared interest in keeping Badger Mill Creek healthy and an enjoyable resource for the community. The District is committed to minimizing harm to the biology of the stream, and analysis has shown that the District’s effluent does not control the overall health of the creek. Discontinuing flow will also benefit the creek in some respects. Without our effluents, chloride and nitrogen levels, which affect stream health, will drop. Removing our warm effluent also moves the stream’s temperature toward more natural conditions, which better supports the stream’s cold-cool water ecosystem. 

Would turning off flow impact Badger Mill Creek or Sugar River?

Specific to the Sugar River, this claim is negligible. A District study, third-party sampling and a historical review of past assessments show that discontinuing District flow in Badger Mill creek could have other positive impacts (see other FAQs) on the Sugar River. Additionally, a recent study led by the District, along with U.S. Geological Survey monitoring records, show that when effluent was discontinued during low-flow conditions, the largest observed difference was a 2-inch reduction of water levels in Badger Mill Creek in the heart of Verona and became even smaller as the water flows to the Sugar River. Without the District effluent contributing to stream flow, the flow at Badger Mill Creek near State Highway 69 exceeded 9 cfs (cubic feet per second) in low flow conditions, with no change to the width of the stream. The District study and submitted observation reports recorded that all observed sites remained flowing during low-flow conditions when the District effluent was removed.

An aggregating effect triggered by flow alterations and diverse landscapes in and along Badger Mill Creek influences downstream water. By reviewing current and historical data, as well as considering stormwater detention, infiltration requirements and farming practice improvements (which have all been implemented in the watershed since the original decision to return the flow to the Sugar River watershed,) it is evident that flow in Badger Mill Creek has increased over time. These additional water sources in the watershed have offset the District’s contribution to the streamflow. This is despite the District’s permit-capped discharge amount, making effluent only a minor contributor to the flow observed in the lower portions of Badger Mill Creek and the Sugar River.

Would turning off flow harm trout?

The District’s effluent exceeds the sublethal criteria set by the WDNR for temperature for limited forage fish, small warm water fishery and cold water community classifications. The most restrictive classification, cold water community, is generally referred to for trout communities. 

The District’s WPDES permit requires reporting for maximum mean daily temperatures. The effluent is up to 20 degrees Fahrenheit warmer than the criteria for trout communities. Because the effluent temperatures are too warm, the District currently has alternate effluent temperature limits approved by WDNR and EPA to discharge to Badger Mill Creek.  

In addition, to the warmer winter temperatures, WDNR trout fishery data notes that for cool-cold mainstem trout streams, which is how Badger Mill Creek is classified, the daily maximum mean temperature should be between 68.5 degrees and 72 degrees Fahrenheit. For the District’s current WPDES permit term, the maximum mean daily temperatures currently exceed those criteria in June, July, August and September. Without effluent, the stream will go back to the natural fluctuation of temperature, allowing for cooler temperatures in the warmer months. 

District effluent also contains chloride and nitrogen, which can impact trout and other aquatic organisms. Warmer District effluent, mixed with chloride, can impact trout populations. Depending on the District as a water source does not provide a realistic and positive long-term outlook for the trout population.  

What types of enhancements will the District provide funding for? How much?

To improve the stream’s resiliency and align with the community’s interests in preserving it for the future, the District will serve as a resource to fund projects that could include stormwater and flood management, removing sediment, adding habitat structures and removing obstructions.  

The budget to support these enhancements will be provided after careful fiscal consideration and approval by the Commission. 

How can individuals and organizations provide feedback regarding the District’s recommendation?

The District’s goal remains to ensure the public’s ongoing interest and feedback in the initiative will be heard. There is another opportunity for the public to provide comments before the compliance deadline. 

  • In-person: Attend the May 11 public hearing in person to provide comments; speakers are encouraged to register their interest at 
  • Virtual: Participate virtually via Zoom in the May 11 public hearing to provide comments; speakers must register: 
  • Written: A public comment period runs April 27 through 4 p.m. CDT May 8. Comments can be submitted at 

When will we know the final recommendation?

The Commission will approve a final option at the May 25 Commission Meeting. The decision must meet the Wisconsin Department of Natural Resources compliance schedule deadline of May 31, 2023. A project implementation phase will begin after. 

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Final Compliance alternative Solution

What did the Commission decide as the final compliance alternative solution in Badger Mill Creek?

On May 25, 2023, the Commission unanimously endorsed the recommendation to discontinue flow to Badger Mill Creek and discharge only to Badfish Creek. Additionally, the Commission approved a substantial financial allocation of $1 million to facilitate the implementation of projects to support the health and resiliency of Badger Mill Creek.  

The decision was based on assessments indicating that Badger Mill Creek no longer requires District discharge to maintain its flow. Moreover, the transition to a single-point source for effluent discharge allows the District to better manage future regulatory requirements and aligns with the District’s sustainability goals and commitment to safeguarding public health, protecting the environment, and managing community resources responsibly and cost-effectively. 

The Commission explored the potential need for future flexibility in allocating additional resources and funds to support the vitality of Badger Mill Creek and Badfish Creek, as identified by various stakeholder groups. 

When will discharge to Badger Mill Creek discontinue?

The discontinuance of returning treated effluent to Badger Mill Creek will not happen immediately. We need to undertake further deliberations and arrangements to determine the appropriate process and timing to discontinue the flow. 

With the approval of the recommendation, the District’s next step is to submit its final compliance solution to the WDNR.

How can individuals and organizations join the stream enhancement stakeholder group?

By September 30, 2023, the District will convene and facilitate a group of governmental and nongovernmental stakeholders and experts. Using a third-party facilitator, the group will work through a process to prioritize interests and needs, which could include flow, habitat and other improvements. Through the collaborative work of this group, a project prioritization and funding plan will be developed and presented to the Commission for approval in September 2024.

How can I stay updated on the project?

The District remains committed to providing transparency throughout this process. As Project PLUS moves into the compliance phase and additional information and timelines become available, we will share them through email and our website.  

Be sure you are subscribed to receive District news here

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Struvite Harvesting

See how we successfully recover struvite, a form of phosphorus, from wastewater for reuse.

Yahara WINS

Learn about a program that works with landowners to reduce phosphorus runoff across the watershed.

Reduce Pollution

Read the blog article “Simple ways to reduce phosphorus pollution” for tips for your home or business.

Phosphorus Rule

Get an overview and summary of Wisconsin’s Phosphorus Rule from the Department of Natural Resources.