The Real Cost of Salt Use For Winter Maintenance In The Twin Cities Metropolitan Area

Minnesota’s seven county, Twin Cities Metro Area (TCMA) uses about 349,000 tons of road salt each year (Sander et al. 2007, based on salt purchasing records). The chloride in salt is a toxic pollutant that accumulates over time in our waters. Thirty-eight stream reaches, lakes and wetlands are impaired for aquatic life due to high concentrations of chloride in the TCMA according to the Minnesota Pollution Control Agency’s (MPCA’s) 2014 Proposed 303(d) List of Impaired Waters (MPCA 2014a). To examine the cost savings and other benefits of reducing salt use, scenarios were created to show hypothetical reductions of salt use from 10 to 70% at 10% increments. Seventy percent was selected as the upper bound since it is the approximate reduction needed for the Shingle Creek Total Maximum Daily Load (TMDL) Study, the first chloride TMDL in the State of Minnesota (Wenck Associates 2006). It is not known at present whether other requirements, safety foremost among them, can be met with a salt use reduction as high as 70%.