I have pairs of both Keen and Simms wading sandals. Both of mine are about 4-6 years old, and were designed for wading (both have faults in that regard that may have been addressed in newer style changes - for example my Simms sandals have crappy Velcro that does not stay closed all of the time when wading) and neither were designed for hiking, although I hiked in to a remote river with a friend once who wore Simms wading sandals, apparently without a major problem. I believe if you want to hike, you should get footwear designed for hiking, not wading. And if you want to wade, get footwear designed for wading.

So, in my opinion, I would take 2 pairs with me, as already recommended. Otherwise, you open yourself up to problems.

That being said, when I was a kid I often rode my bike several miles to go fishing, wet waded most of the day in a small mountain trout stream with rubber soled tennis shoes, wore these wet shoes home, dried them out over night (more or less) and probably played baseball with these same shoes the next day. But, that was the only pair of shoes I had at the time. Then, as an adult I fished for many years wearing inadequate footwear (winter steelhead fishing at 18 below zero, for example - but that's another story). Now, some 50-60 years later, my feet are suffering from years upon years of such abuse! Don't be penny-wise and pound foolish.