First, this is my design that I have created just for this purpose. I have not DS any layers at this time.
The bridge is quite close but I want to make it look as if there is sand over it without adding another layer of sand. No problem!
Grab the eraser. I am using one on 95 and lower the brush hardness down to 13%.
I used circular strokes on the pier layer and this is what it looks like now.
Just like if you had been on the beach, with many beach-goers kicking up sand on the wood! You can do this for almost anything sitting on the sand as well.