That tradeoff between winter safety and the quality of our local waters is a tough one. None of the experts I talked to for today's story on salt pollution in urban lakes and streams said that we should or could stop using road salt. But it's clear that there is far more salt on roads and sidewalks than we need to keep them safe. So the first step, they say, is minimize minimize minimize.

At this point, though, no one knows whether cutting back on road salt would make a significant difference in the water. The PCA and local watershed districts are just beginning a four year project to measure how much salt is in local lakes and streams, and as cities cut back, that might show up as well over time.

But it took decades for the salt to rise, and it will take decades for levels to fall again. That's the nature of our relationship with water.

The Minnesota Pollution Control Agency has a huge web site devoted to its Twin Cities road salt reduction project. You can find any and everything you'd like know here. It includes educational materials for all.