Early chronicles show that, since the 13th century, the land mass of Sylt has shrunk by about two thirds. The southern spit is especially vulnerable to storm surges, causing long term depletion to the Hörnum Odde.
A number of coastal protection measures have been tried over the years, from building dykes and planting dunes to erecting breakwaters or tetrapods. Since 1972 the most effective defence against the sea’s continuous onslaught has been sand replenishment. Special ships anchored off the coast steadily pump sand through pipelines on to the beach and the sand is evenly distributed by bulldozers. The storm tides thus carry away this protective cushion of sand, rather than the actual coastline. A wide flat beach ensures that the waves have space to peter out, diminishing their destructive power.