In the past couple of weeks many of us have seen more snow than we’ve seen in a lifetime. Since I grew up in Minnesota however, the five-foot snowbanks and freezing temps feel just like home to me. When the first snow falls, I immediately yearn to make snow angels and go skating. But for many, the snow can be a real nuisance. So is there a bright side for those for whom the first snow signals it’s time to book a trip to Florida?
Snow and Water Supply
On Worldview today, Jerome McDonnell and I decided to explore whether there is anything redeeming about snow. Our guest was Tim Loftus, PhD, Water Resource Planner for Chicago Metropolitan Agency for Planning (CMAP), who spearheaded CMAP’s recent report on Northeastern Illinois water supply issues. Tim’s view is that snow is important at least somewhat for replenishing the water supply. But here in Illinois, snow really only replenishes our drinking water when it falls on Lake Michigan and other open bodies of water. As climate change proceeds, Tim says snow will become even less important as the proportion of annual precipitation from rain in the Chicago region will increase as the amount of snow decreases over time.
Tim points out, though, that in the mountain West, snowfall is significantly more important for restoring the water supply than here in the Midwest. This is because in the mountains, melting snow occurs gradually over many weeks or months and flows down gradually refilling the reservoirs and rivers. While a decrease in snowfall in the Great Lakes region is not likely to have much impact, the same trend in the mountain states will be a significant cause of drought, straining water supplies needed for irrigation and for drinking.
Would You Like Salt With That?
Here in Chicagoland, the key issue regarding snow is actually sodium chloride, a.k.a. salt. The rock salt that we use to ice our roads and sidewalks washes away when the snow thaws, ending up in the storm sewers and eventually, in our drinking water. Salt also dries out the soil and can be damaging to plants. While there are some alternatives to salt, it is the most common solution for dealing with ice. Tim points out that the short-term advantage of using salt, namely safety, is an important reason to we continue to use it as a de-icer. However he says the long-term cost is the accumulation of salt in our water supply. As a result, our grandchildren may have to de-salinate their water in order to drink it, a very expensive and energy-intensive process.
One Green Thing
The alternative to using salt that Tim recommends is sand. Although it does not melt ice as efficiently as salt, sand is a more benign solution. Sand does not hurt the garden and does not hurt the plants. But, as with salt, it is possible to overuse sand. If sand washes into the storm sewers, the silt can end up clogging sewer pipes and adding sediment to the water. But it is still not as damaging as salt.
The lesser of two evils for making icy winter surfaces safe for walking and driving is to use sand. The One Green Thing you can do: Replace your sidewalk salt with sand to keep chloride out of the water supply—and to save money for your grandchildren so they don’t have to de-salinate their drinking water.
—As part of our partnership with Chicago Public Media, this content may also appear on WBEZ 91.5.