You may have noticed that it has been raining. You may be thinking this is good, what with the long-term dry weather we've had.

Actually, the timing couldn't be worse.

The heavy rains are hitting just before the city of Madison and other municipalities were set to do their spring cleaning. The public works departments needs to wait until the snow is gone before it can do comprehensive street sweeping to pick up all the debris that has accumulated in the gutters. And there is even more of that than usual this spring, as we had more bigger snow events than we do over a typical winter.

But before the street sweepers could be deployed, the rains started, washing much of that sediment right into the Madison lakes. To make matters worse, farm fields are at just the right time to produce a lot of runoff -- mostly thawed but without vegetation.

As UW limnologist Steve Carpenter explained it to me in an email this morning: "There will be a lot of erosion. The lakes will receive a big load of phosphorus and sediment this week."

Phosphorus grows algae, that scum you see in the lakes in the summer months.

A lot can happen during a season of lakes usage, but we're not getting off to a good start.