Beach reclamation is simply providing more sand for a beach that is eroding. I have linked a site that has a terrific explanation of dredging, which is a common method of beach reclamation. 

Jetty's are long narrow barriers, often made of rock, which prevent waves from washing sand into harbors. They also prevent large waves from crashing in the harbor.

Studies of the historical changes in the mean high-water shoreline of Georgia indicate that the basic causes of shoreline erosion are:

—The worldwide rise in sea level (an average of one to two feet per century);
—Seasonal storms and hurricanes. The Georgia coast has not had a major hurricane (defined as at least a category 3 hurricane) since the late 1890s;
—Man's activities, including channel dredging with offshore disposal of dredged material, jetty construction, shoreline structures, and damming of rivers.

Georgia's coast islands and beaches are composed largely of sediment which has eroded from the highland and mountainous regions further inland.

You can learn more about beach erosion here.