Overview--from Dept of Public Health report
"Despite nearly 50 years of concern, observation and efforts at reduction, the use of road salt continues to increase. Monitoring of surface and ground water continue to show increasing trends in chloride and sodium levels, although the levels are not yet a human health hazard. Storm water monitoring during snowmelt has identified surges of extremely high levels of chloride. As these surges enter local waterways, they have the potential of harming fish and other aquatic organisms. Additional efforts to reduce road salt applications are needed if Madison is going to achieve the goals set in the 1970s. New information in this report includes a decade by decade look at salt reduction efforts and how they affected chloride levels in Lake Wingra." Source
Click on graphs to enlarge. The lower graph shows that various measures to reduce salt use around Lake Wingra have caused temporary dips in salt in the lake. But despite these efforts, salt levels have continued to rise.
City Policy"Our lakes are one of the things that make Madison a great place to live. Their natural beauty offers us scenic views and a wealth of recreational opportunities. These precious resources require a good deal of care and attention if we are to preserve them for future generations.
One big problem facing our lakes is the steady rise in chloride levels. The chloride comes largely from the salt that is applied to our streets and highways in the winter. The chloride levels in the ground water we drink are also increasing for the same reason.
In order to protect our drinking water and our lakes the City of Madison uses far less salt that most communities in Dane County and across the snow belt. The Streets Division will only use salt on main arterials, thoroughfares, main connector streets, Madison Metro bus routes, streets surrounding hospitals and schools and major hills and curves. All other City of Madison streets receive sand to act as an abrasive on hills, intersections and curves. This policy may mean that you will have to slow down in winter and leave a bit earlier to arrive at your destination on time. Remember when you do these things that you are just doing your part to preserve our drinking water and our beautiful lakes."
Snow plowing and salting frequently asked questions.
References
Report by Public Health Madison-Dane Co., 2011. Excellent summary!
