The recovery of Upper Prior Lake hinged on a few simple radio tags. The next time the Prior Lake-Spring Lake Watershed District put their nets in the water, they did not come up empty. Over the past 10 years, Upper Prior Lake has been brought back to life. This summer, the Minnesota Pollution Control Agency recommended removing Upper Prior from its impaired waters list for nutrients. The lake is part of a small chain in the center of the city of Prior Lake where the water flows north.