It’s been more than a decade since Wisconsin cracked down on phosphorus. Has it helped protect our lakes and rivers?

Noted: Phosphorus runoff also increases after extreme precipitation events, which are projected to be more frequent as the climate changes. A 2017 study from the University of Wisconsin-Madison’s Center for Limnology found that phosphorus “pulses” into waterways after extreme rainfall, building on previous research that showed waterways receive most of their phosphorus in just a dozen or two events per year. The bigger the rainstorm, the more phosphorus was flushed downstream, the UW study found.