Coastal developments are the cause of beach erosion AND the case for "replenishment".
I would encourage anyone who lives in MD to read about the current state of Assateague. It's shrinking, and the ultimate cause is the continued beach replenishment in Ocean City to the north. Sand dynamics is a VERY complex science. If we cannot get our politicians to agree on the simple things like evolution and a helio-centric solar system, how on Earth could we expect them to understand something far more sophisticated?