REEF TYPE BREAKWATERS

Reef type breakwaters refers to a low-crested rubble mound breakwater without the traditional multilayer cross section. This type of breakwater is little more than a homogenous pile of stones with individual stone weights sufficient to resist wave attack. In recent years a number of low-crested breakwaters has been built or considered for use at a variety of locations. Most of these structures are intended to protect a beach or reduce the cost of beach maintenance. Other applications include protecting the water intakes for power plants, the entrance channel for small boat harbors, and providing an alternative to revetment for stabilizing an eroding shore line. In situations where only partial attenuation of the waves on the leeside of the structure is required, or possibly even advantageous, a low-crested rubble mound breakwater is a logical selection. Since the cost of a rubble mound increases rapidly with the height of the crest, the economic advantage of a low-crested structure over a traditional breakwater that is infrequently overtopped is obvious. Because the reef type breakwater represents the ultimate in design simplicity it could be the optimum structure for many situations. Unfortunately, the performance of lowcrested rubble mound structures, and particularly a reef type breakwater, is not well documented or understood.