Chicago Area Waterways Chloride Initiative Work Group

In its mission to protect the area’s local water quality, the Metropolitan Water Reclamation District of Greater Chicago (MWRD) is coordinating a stakeholder group to address chloride levels in area waterways. Rock salt (sodium chloride) and salt runoff are harmful to wildlife, insects, surface water and soil along roadways and sidewalks. Sodium chloride and impurities in road salt end up in runoff from rain, melted snow and ice, and are released into local environments by the splash and spray caused by vehicles. Road salts travel onto vegetation, into the soil and groundwater, through storm drains and into surface waters. Chloride in surface waters can be toxic to many forms of aquatic life, including fish, insects, amphibians and macroinvertebrates, which live in water for all or part of their lives and are a significant part of the food chain for fish and birds. Studies show that chlorides in urban streams have increased substantially over the last 50 years, especially in northern metropolitan areas like Chicago.

In 2015, the Illinois Pollution Control Board (IPCB) finalized a new water quality standard for chloride for the Chicago Area Waterway System (CAWS) and Lower Des Plaines River. The new water quality standard for chloride will go into effect on July 1, 2018. Because of the adoption of the chloride water quality standard, where necessary, the Illinois Environmental Protection Agency (Illinois EPA) will be obligated to incorporate chloride limits into the National Pollutant Discharge Elimination System (NPDES) permits.

As an NPDES permit holder with jurisdiction over most of Cook County, the MWRD was asked by the Illinois EPA to form and administer a stakeholder work group with the ultimate goal of reducing chloride discharges and resulting impacts to the waterways. Led by the MWRD, the CAWS Chloride Initiative Work Group is developing a technical report that can be used to support discharger variances from the chloride standard that would be filed with the IPCB. The technical report will address best management practices to reduce salt usage, water quality benefits, and social and economic impacts of salt use reduction. A variance is a relief mechanism granted by the IPCB that allows petitioners to address the high chloride problem without being subject to a chloride water quality standard for a specified time period.

Currently, many reaches of the CAWS would not always meet the new chloride water quality standard of 500 milligrams per liter (mg/L) during winter months. The CAWS Chloride Initiative Work Group is assessing current water conditions, documenting current road deicing activities, developing a pollutant minimization plan, identifying opportunities to reduce road salt runoff while maintaining public safety, and then implementing the plan and documenting progress. The Work Group consists of committees that include a legal committee coordinating the preparation of the petition; a BMPs committee coordinating the needed solutions; a data acquisitions committee; a water quality committee; and a social and economic impact committee. The goal of the Work Group is to prepare the technical report, organize training workshops, and to assess the water quality benefits of best management practices in an ongoing manner.

To view past meeting agendas and presentations or learn about future meeting dates for the Chloride Initiative Work Group and its committees and additional watershed planning council meetings, please click on the meetings link below or view any of the additional links.


arrow Meetings
arrow CAWS Chloride Water Quality Data
arrow Kick-off Meeting Letter
arrow Follow-up Meeting Letter
arrow 2015 Chicago Area Waterways Deicing Survey


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