A Chloride Impact Study for the Southeastern Wisconsin Region

The Commission staff prepared a Prospectus for a comprehensive study of the environmental impacts of the use of chloride on the surface water and groundwater resources of the Region. A Technical Advisory Committee (TAC) was formed (roster to the right), and that committee met in 2015 to complete the Prospectus (summary notes for those meetings can be found under "Meeting Materials" below).

Work began on the Study in summer 2017 with Region-wide monitoring as outlined in the Prospectus. This included continuous monitoring for specific conductance at about 41 stream locations throughout the Region. Following a detailed site selection process and in-stream monitoring equipment deployment, a two-year comprehensive data collection period began in October 2018 and concluded in October 2020. Additional data collection at selected sites continued into spring of 2021. Monthly grab samples were collected at each site, along with targeted event sampling, to obtain water quality data that include chloride concentrations. Additionally, quarterly sampling was performed at six lakes within the Region, collecting temperature, specific conductance, and chloride data at various depths. Figure 1 compares the draft seasonal chloride profiles for two lakes in the Region, Moose Lake and Little Muskego Lake.

Previous studies have demonstrated that specific conductance is a good predictor of chloride concentration once a reliable relationship is established. Specific conductance, collected at 5-minute intervals at each monitoring site, is paired with the corresponding chloride concentration obtained from sampling and will be used to develop regression relationships. Figure 2 shows the preliminary paired study data for all of the Commission monitoring sites. The best-fit chloride-specific conductance relationships will be used to estimate chloride concentrations based on the observed continuous specific conductance data. 

Work has begun on the technical reports for the Study and the TAC began meeting again in 2022 to review Study efforts and provide input. Currently Commission staff are developing technical reports summarizing the field work and the impacts of chloride in the environment.  Professor Strifling and students at Marquette University Law School are leading the development of a technical report for the legal and policy considerations for chloride management.  Commission staff continue to work on the regression analyses, the analysis of mass balance of chloride sources in the environment of the Region, and researching state-of-the-art practices and technologies affecting chloride in the environment. All of these subjects will also be documented in technical reports for the Study.  Draft technical report chapters will be posted on this website for review and comment as they are completed.

TR-64 Regression Analysis of Specific Conductance and Chloride Concentrations (Preliminary Draft)

Chapter 1 – Introduction

Chapter 2 – Methods

Chapter 3 – Results

Appendix A – Acronyms and Abbreviations

Appendix B – Lake-Specific Regressions for Lakes Sampled as Part of the Chloride Impact Study

Comments will be taken on the Draft TR-64 text until May 17, 2024.


4-17-24 Chloride Study TAC Meeting Presentation (TR-64 Review)

1-31-24 Chloride Impact Study TAC Meeting Presentation (TR-62 Chapters 3, 5 review)

11-10-23 Chloride Impact Study TAC Meeting Presentation (TR-67 review)

6-28-23 Chloride Impact Study TAC Meeting Presentation (TR-61 review)

4-26-23 Chloride Impact Study TAC Meeting Presentation (TR-62 Chapters 1, 2, 4 review)

11-9-22 Chloride Impact Study TAC meeting presentation

1-19-22 Chloride Impact Study Update presentation to WDNR staff

6-5-20 Chloride Impact Study Presentation at the Healthy Lakes Conference

3-29-19 Chloride Impact Study Update Presentation


Meeting Materials

4-17-2024 TAC Meeting Summary Notes

1-31-24 TAC Meeting Summary Notes

11-10-23 TAC Meeting Summary Notes

6-28-23 TAC Meeting Summary Notes

4-26-23 TAC Meeting Summary Notes

11-9-22 TAC Meeting Summary Notes

6-5-18 Summary Notes

10-21-15 Summary Notes

9-8-15 Summary Notes



Please use the comment box below to submit comments or questions you may have about the Chloride Impact Study at any time during the planning process.

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You can also submit comments and questions to Laura Herrick, SEWRPC Chief Environmental Engineer, at lherrick@sewrpc.org  

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Southeastern Wisconsin Regional Planning Commission

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Milwaukee, WI 53204

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E-mail: sewrpc@sewrpc.org


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