Engineered structures are appropriate particularly in areas of intense erosion or where suitable sand sources are not available.
In the 1997 Ocean Ridge Shore Protection Project, 8 t-groins were constructed using granite boulders transported by rail from Georgia.
A geogrid fabric was attached to a metal frame and lowered onto the sand using a back hoe.
The frame was removed after the geogrid was secured in place by the boulders, which weighed up to 3.5 tons.
The geogrid fabric prevents the boulders from sinking into the sand.
More granite was placed in a t-shaped form, according to a surveyed template.
The eight t-groins, shown under construction in this aerial photo, will retain the sand along this highly erosive beach.