For crossing deep fast flowing streams I use these neoprene triboard shoes (Decathlon). They fit like socks, so the flowing water doesn't get much hold of them (unlike sandals, Crocs etc). They have pretty tough grippy soles and protection all around to prevent my feet from getting injured by stones etc. As a bonus, they give an element of heat insulation, which can be very nice when you have to spend a long time finding a way through a raging, ice-cold melt water stream, because your feet get numb from the cold very soon, which eventually impairs safety.
It is something extra to carry (345 grams/ pair) but they can double as camp shoes and I find they really help with safe crossings while keeping my boots dry. They were cheap too (less than £10).