More than 800 rowers will be on Milwaukee’s waterways Saturday as part of the 23rd Milwaukee River Challenge, but the river and waterways are a much different sight than they were just 23 years ago when the annual race started. “The initial goal of the race was to bring people down to the river as we were working to revitalize it. And so to have the river walk and to have the river be as clean as it is and have it be a place for such a spectacular race, it means the world,” race director Alyssa Remington said. Remington said the rivers have seen a big change since she started rowing in Milwaukee during the early 2000s.“There was all kinds of debris floating in the water. You know, you wanted to make sure that you didn’t get any of the water splashed on you. You were very cautious right …