GROINS:  These are built in groups (groin fields) perpendicular to the shore to trap sand between them.  They can decrease erosion in the pocket beach they enclose, but erosion is often increased downdrift of the groins.

VEGETATION:  Planting vegetation on the dunes can help to anchor beaches.  Some plants such as sea oats serve this function naturally, but sea oats are fragile and now endangered

BREAKWATERS:  Built offshore and parallel to the beach to block incoming waves and dissipate their energy.  They can cause extra sand deposition behind the breakwater, which extends the beach

BEACH FILL/RENOURISHMENT: Placing large amounts of sand onto an eroded beach to bring the beach profile up to a more desirable level.  After the initial fill, the process must be periodically repeated ? this is known as renourishment

SEAWALLS:  Built at the land's edge to resist the waves.  A seawall can actually speed up erosion, as sediment is scoured away at the base of the wall