In a study of St. Lucie Inlet, which forms the north boundary of 

 Jupiter Island, Walton (1974) estimated that the annual net southerly 

 longshore transport rate passing the north jetty was 100,000 cubic yards 

 (76,500 cubic meters). However, the total volume crossing the inlet and 

 continuing downcoast was estimated at only 30,000 cubic yards (22,950 

 cubic meters) per year, with the remainder either permanently trapped 

 by the inlet or transported offshore. 



A cooperative study by the University of Florida (1969) focused on 

 a series of tests using a drag scraper for beach nourishment from off- 

 shore borrow sources at Jupiter Island. 



The area has been the subject of a number of investigations includ- 

 ing those by Purpura (1962), Bruun and Monohar (1963), and Bruun, Battjes, 

 and Purpura (1966). Most of these studies dealt primarily with coastal 

 engineering problems such as shape and placement of groins, seawalls, and 

 inlet jetties, rather than general long-term changes in the coastal con- 

 figuration, 



A preliminary analysis of the data collected during this study has 

 been presented by Richter (1971, 1972, 1974). 



2. Study Area . 



Under Shepard's (1963) coastal classification, the southeastern 

 Florida coastline, with its lagoons and offshore islands, is a barrier 

 coast. Tanner (1960) described it as a "perched" barrier coast; i.e., 

 the sand is merely a thin veneer spread over Pleistocene coquina, sand- 

 stone, and limestone bedrock. Exposures of this bedrock, usually assign- 

 ed to the Anastasia Formation, are visible at a number of places along 

 the coast (Cooke, 1945; Puri and Vernon, 1964). Outcrops, such as those 

 at Boca Raton, exhibit typical wave-cut cliff and platform features. 

 Tanner further classified the area as an eroding, nonequilibrium coast 

 but felt that the coquina at or near sea level effectively retarded 

 the erosional process. Offshore profiles for Jupiter, Boca Raton, and 

 Hollywood, from the beach to the shelf edge, were plotted from National 

 Oceanic and Atmospheric Administration, National Ocean Survey (formerly 

 U.S. Coast and Geodetic Survey), unpublished boat sheets (Fig. 2). Typi- 

 cal beach profile shapes are shown in Figure 3. 



a. Jupiter . The Jupiter site is located in the northeast comer of 

 Palm Beach County, approximately 80 miles (128 kilometers) north of Miami 

 (Figs. 1 and 4). Of the three sites, it is least affected by the wave 

 shadow of the Bahamas and the most exposed to the north Atlantic--through 

 a 70° sector from approximately N. 05° W. , where the nearest coastline is 

 Cape Canaveral, to N. 65° E. , where the Little Bahama Banks afford pro- 

 tection from waves approaching from the east. The effective fetch from 

 the east, through a 45° sector, is limited to about 50 miles (80 kilo- 

 meters). Exposure to the southeast through a 50° sector, is open to an 

 approximate 100-mile (160 kilometers) fetch. Jupiter has a relatively 

 straight coastline bearing about N. 17° W. 



13 



