Folks who live near the St. Croix River like to brag that when their river flows into the Mississippi, it makes the Mississippi cleaner. The St. Croix runs 150 miles along the Wisconsin-Minnesota border before it joins the Mississippi near Hastings. The condition of many waterways around the state has Minnesotans wringing their hands over pollution and blighted scenery. But for most of its length the St. Croix is clean and quiet. It is rich with spectacular views, great fishing and a long history. Yet Twin Cities commuters are pushing east in search of an improved quality of life. The St. Croix now winds through one of the fastest-growing parts of the state. Those who care about the river are trying to keep their good thing going. As part of our series "Changing Currents," Mainstreet Radio's Jeff Horwich visits the St. Croix with some who know it best.