To think those traveling artists may have had an engineer among them that had an Educated Idea
of where the water line may be, if the rivers canyon mouth had a dam. At the time, they were working
all along the tops of the mountain canyon's ridges. Many worked boulders are underwater in these pics.
The mid-summer level is well below max flood & well above draught levels, when many more markers are
exposed. What would they think if they could see it all, their works at the edge of ridges, coves at the waters
edge, just because that's where most of the ancient bedrock was, at a favorate spot along a well traveled trail.