To answer your question: not a dune that is only build for a period of the year. Will the dune be removed after winter?
The Netherlands is under sea level for the biggest part so we have (badly take care of) dunes and if it's high water (big rivers flow this way) parts will be flooded. Is that bad? It's nature and we are used to wet and cold feet although we don't like it.

Where do you walk? Do you climb over the dune to be on the beach? Enjoy your walks I wish I had a beach nearby.