How to get water to affect landscape "wetness"

Hi there, I have a landscape set up and a water plane that creates lakes and oceans. I have the water working with “Distance to Nearest Surface” to add shoreline effects, but I would like for the water on the shores to affect the landscape wetness to give it a more realistic look. I could use distance to nearest surface again, but then any object that I place on land will make it wet. Is there a way in the material to specify that it is only the water material that it reacts to, or even the water plane mesh? I’m fine with having to do this in blueprints as well. I just don’t want to have to paint vertex colors around all my shorelines as that would take a very long time. Any tips or pointers would be great!

You need to calculate water level in landscape’s material and change the roughness depending if pixel is below the water level or above it.