Breakwaters can take the form of headland breakwaters or nearshore breakwaters. Headland breakwaters can be constructed to mimic rocky cliffs that encourage the formation of pocket beaches. Waves will break at angles to the shoreline causing sediment transport and shoreline shape adjustment until a full equilibrium shape is reached. At this stage, beaches will remain stable.
Headland breakwater systems have been built along the shoreline of the Chesapeake Bay for shore protection and to maintain recreational beaches. Since 1985, 60 breakwaters at 19 sites have been designed, constructed, and monitored.
Nearshore breakwaters are detached, shore-parallel structures that reduce wave energy to a protected area. The reduction in wave energy slows littoral drift and produces sediment deposition and a salient feature, or shoreline bulge, in the sheltered area behind the breakwater. Some longshore sediment transport may continue behind the structure along the coast.
Nearshore breakwaters modify currents around them, which results in the accretion of sediment directly behind the structures. These breakwaters reduce offshore sand transport during storms; therefore they help retain sand on nourished beaches, protect upland areas, provide recreational beaches, and create or stabilize wetlands. An extensive system of nearshore breakwaters has been used to protect 8.3 km of Lake Erie shoreline at Presque Isle, Pennsylvania.