A saltier lake? A recent report by WBEZ radio looked at how much road salt ends up in Lake Michigan from Chicago's streets. Not so much, it turns out, because most of the City's runoff goes to the Chicago River and (because the river is reversed) heads west to the Des Plaines on its way to the Gulf of Mexico. But we know that north shore ravines drain directly into the Lake. What does the report say about Lake Michigan salinity? Current Lake Michigan chloride levels are around 12 milligrams per liter(mg/L) (according to the IEPA), far below the USEPA's standards of 500 mg/L for "General Use Waters." However, if you measure the lake's springtime chloride levels, they have risen almost 50 percent since 1980. To see the full report click here.