Thanks for the comments Alan, Jameel, Ben, and Jim!
Alan: I don't think there's cause for concern. I think they're just backlit in golden hour light. The brown is flowers!
Jim: Little Yosemite Valley was certainly interesting. They've improved the pit toilets a lot since I was last there, but people are still pretty bad about keeping things clean in the area (mostly not picking up toilet paper that they dropped and then tracking it out...
I'm not sure if the effect is appropriately subtle or too subtle on the waterfall shot. It was a 2 second exposure where I zoomed from 24 to 70mm in the last half second. You can see the effect if you know what you're looking at (I think).
Tim