I have a boat at the confluence of the Illinois and Mississippi River. Sometimes the current is super strong. Ask David Scalley. It was like swimming in an infinity pool. Usually by later fall you could swim the Illinois River. But I wouldn’t do it alone or without support and a boat and a swim-it. Usually the current does die down. While I have no idea how strong the current is in Louisville. I stressed over it in Chattanooga for 6 months. What I found is that it was not all that bad. You felt it and swam slower but you still keep moving and once past swimming against the current it was great. But it was much better than I imagined.