My kids have just turned 11 and 14, and in all seriousness, both of them have almost died several times due to medical pros not taking the symptoms seriously enough. All long stories BUT one time we were in Havasu parked in a cove all by ourselves. The younger son was about 2.5-3 years old. We had been beached for only a few minutes and Momma was in the boat making sandwiches. I left the beach and the boys and walked out into the water to cool off. In less than a minute I cam walking back up to the back of the boat in about 5 feet of clear water. My baby boy is bicycling like a mother fucker under water !!! EEECK ! I don't know how he got there. No one can hear him because he is completely under water. And I have no idea how long he has been there. So I shit my pants and scoop him up onto the swim deck much to everyone's surprise.
My older son had swimming lessons when he was only a few months old. It is easy to teach new babies to roll over on their backs and stay there until someone comes to ge them. Swimming by 9 months ain't too hard either. We should have done it with the younger one but we didn't. He's not afraid of the water but he will never be the "fish" his older bro is.
I'm telling you this just cuz things happen real fast with babies. But honestly the biggest danger with real small kids at the river is heat. They get dehydrated and burned real easy and they don't have the reserves that bigger kids have. Kids can suffer organ damage real quick if they get too dehydrated or even just over warm for long periods of time. Lots of hidden dangers with small kids, you have to be super vigilant at all times. And that ain't always easy to do when having a good time on the water. Kids are a game changer my man. Good luck to you both.