Q. How are the lakes impacted by a rough winter like this one, with crews spreading so much salt on the roads? A. If more road salt is used, more will end up in the lakes, says Stephen Carpenter, a zoology professor in the UW-Madison Center for Limnology. A heavy winter is likely to add salt to the lakes. It also adds a lot of meltwater, which dilutes the salt.
Over time, road salt levels have slowly been building in all the Madison-area lakes, he says. Lake Wingra has higher concentrations than the other lakes, because it has the highest proportion of urban area in its watershed.
It's unclear exactly what effects all that salt will have, though the sodium chloride increases salinity and may have ecological consequences. As we move the lakes toward a saltier environment, it might be harder for native plants and animals to compete and more favorable for non-native plants and animals, Carpenter says. For example, the invasive aquatic plant Eurasian watermilfoil is fairly salt-tolerant. Lakes aren't the only water around, and it's possible salt could affect groundwater too.
Alternative road de-icers might avoid some of these salinity problems, Carpenter suggests. But these are more expensive.
— Produced in cooperation with University Communications
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