I cast in plaster at the base of the dune where the water meets the wall. Two of my casts stood up sculpturally, looking like fossils or scholar rocks.
This was a nice surprise and different from the other plaster sand casts. It was interesting to find places where the flow could be captured in a fluid medium, to learn how to make the dams for lakes of plaster.
Below the plaster is setting at the base of the dune. I came back days later and lifted the casting. It was hard to find after more clay and sand had fallen, covering it up.