Wausau Whitewater Park is downtown Wausau, WI.  This is a bypass off the main river that is natural but they have made a man made whitewater park here.  They also change the course from time to time by rearranging the boulders that create the whitewater.  They have public releases throughout the summer.  That is they open flood gates to this stretch of river on a schedule basis to create whitewater.  This is a course that has a few contests every year.  This is also used for Olympic trials.