Thirteen years after that fateful canoe trip, then-U.S. Sen. Mondale and Wisconsin Sen. Gaylord Nelson worked to have the St. Croix River designated as one of the nation’s first Wild and Scenic Rivers. The stretch from Taylors Falls, Minnesota, to Prescott, Wisconsin, was added in 1972. Today, there are 226 Wild and Scenic Rivers - a designation given to only one-half of 1 percent of the nation’s rivers. Mondale, who died earlier this month at the age of 93 at his home in Minneapolis, called the St. Croix a “national treasure” and considered his work to preserve it among his proudest political accomplishments, the St. Paul Pioneer Press reported.