Residents in low-lying river areas of Weyauwega, Fremont and New London are being urged to evacuate immediately because of dangerous floodwaters, the Waupaca County Sheriffs Office said Wednesday.Authorities provided the map below, showing the affected zones, and stressed that safety cannot be guaranteed for those who choose to remain in place. Public shelters have been opened at Washington Center Gym, 500 W. Washington St., New London, and Weya…