Again, I have used chalk finish paints and small glass beads to represent the pebbles. Our beach consists of pebbles but there is sand when the tide is sufficiently far out. It matters not, on a bright summer's day you cannot see the beach for bodies!
We do occasionally get snow and it is quite fun to see a snowman on the beach.
There is usually enough flotsam around to decorate him, especially if there has been a storm.