Same for me. I quit wearing sandals on the river a while ago; I got tired of my toes getting munched by rocks and thorns and such. On a trip last week, I tripped over something, and when I tried to recover I ended up kicking a big jagged rock. I was very glad to have close-toed shoes on when that happened.
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I've been tempted to get a pair of 5.10 Water Tennies, but I've never found any I could try on first. A lot of people like them, though.
Even an old pair of sneakers or low-to-mid cut hikers work better than sandals, IMO.