I wouldn’t consider it at all. The backwaters are full of random deep channels under the water. There’s nothing worse than dropping a bird and not being able to retrieve it due to depths. Or walking in 2′, just to take a step into 6′ and go under. Been there, done that…managed to recover the shotgun too…
The Mississippi isn’t a river to be messed with. It’s vastly underestimated by most. I would, at the very least, use a kayak or canoe. I would also stay out of the main channel in one. Doesn’t seem that dangerous but 40 degree water temp and 15 degree air temp, mixed with a moderate current isn’t something to gamble with…