cubic yards (640,000 cubic meters) of material from Kobe Sound and the 

 Intracoastal Waterway was pumped onto the beach between 1957 and 1963 

 (U.S. Army Engineer District, Jacksonville, 1968). In September 1963, 

 borrow material from a zone 600 to 800 feet (180 to 245 meters) offshore 

 was placed on the beach with drag-scraper equipment (Gee, 1965). Although 

 exact fill volume data are not available, a total of 500,000 cubic yards 

 (382,500 cubic meters) was to have been placed over a 3-year period (U.S. 

 Army Engineer District, Jacksonville, 1968). Between June and October 

 1973 a total of 2.5 million cubic yards (2.3 million cubic meters) of 

 sand was pumped from offshore and placed along 16,800 feet (5,121 meters) 

 of beach (Strock and Noble, 1975). 



About 36,000 cubic yards (27,540 cubic meters) of material has been 

 dredged annually from the St. Lucie Inlet since 1964 (Walton, 1974). 

 Most of this material has either been dumped offshore or along the 

 dredged channel, not placed directly on the adjacent beaches. How much 

 of the spoil material remains in the littoral zone and is subsequently 

 transported alongshore is unknown. 



b. Boca Raton. The Boca Raton site is located in the southeast 

 comer of Palm Beach Coionty, approximately 40 miles (64 kilometers) north 

 of Miami (Fig. 1). The shoreline trends N. 05° E. and has an intermediate 

 exposure to open ocean waves, through a 30° sector from N. 10° E. to N. 

 40° E. A narrow "window" of exposure opens from N. 76° E. to N. 79° E. 

 through the Northwest Providence Channel, separating Grand Bahama Island 

 and Andros Island, about 60 miles (95 kilometers) from the mainland. 

 Open exposure to the southeast is limited to a 24° sector from S. 19° E. 

 to S. 04° W. 



The site is 2.5 miles (4.0 kilometers) north of Boca Raton Inlet and 

 12 miles (19.2 kilometers) south of South Lake Worth Inlet, Coquina 

 limestone crops out at about mean low water (MLW) and is generally ex- 

 pressed as a relatively smooth planar ledge dipping seaward (east) at 

 4° to 8° (Fig. 5). At times, this ledge is completely covered with sand. 

 More often, it is exposed with the seaward edge forming a dropoff of 

 from 4 to 5 feet (1.2 to 1.5 meters) about 50 feet (15 meters) from the 

 MSL shoreline. The coquina ledge has dense seasonal growths of encrust- 

 ing algae, sponges, and worm reef {Sabellajnidae) (Kirtley, 1966). The 

 coquina becomes the dominant shoreline feature about 2 miles (3.2 kilo- 

 meters) south of the site, forming two minor promontories with maximum 

 elevations of approximately 20 feet above MSL and an alongshore dimen- 

 sion of about 400 yards (360 meters) (Fig. 6). 



The beach at the Boca Raton site is also steep and narrow with a 

 typical width of about 100 feet and a 1 on 9 slope. Seaward of the 

 coquina ledge the slope is about 1 on 100. The frontal dune is heavily 

 vegetated and has a maximum elevation of about 25 feet (8 meters). 



The beach- front property at Boca Raton has been subject to intensive 

 development during the study period, with the construction of high-rise 

 condominiums essentially on the dune line (Eyre, 1971). A section of a 



17 



