original fill material remains on the upper beach. During this time, the 1968 

 artificial borrow pit, which parallels the beach about 430 meters (1,400 feet) 

 from shore, has shoaled to about half its original depth with sand moving in 

 from deeper water. The position of the borrow zone, just seaward of the 9- 

 meter MLLW contour, was thus well chosen for this site as it is beyond the 

 zone of cyclic onshore and offshore sand transport of beach material. Large 

 volumes of sand are transported offshore at Redondo Beach during storms and 

 particularly during the winter season, then returned by natural onshore trans- 

 port during summer swells. The offshore borrow pit is far enough seaward so 

 that it does not trap this beach sand or interfere with its cyclic exchange 

 between the beach and the nearshore profile. 



This was the first project in the United States where a hydraulic 

 pipeline dredge was operated successfully in a high wave energy coastal 

 area. Although highly successful in this project, this procedure has a 

 critical limitation — the necessity for a nearby harbor. The experience gained 

 on this project and the hopper-dredge operation at Sea Girt, New Jersey 

 (Mauriello, 1967; U.S. Army Engineer District, Philadelphia, 1967) provided 

 the techniques for many subsequent beach nourishment projects that utilized 

 offshore sand deposits. 



c. Dade County, Florida (U.S. Army Engineer District, Jacksonville, 

 1975). The Dade County Beach Erosion and Hurricane Protection Project, which 

 includes Miami beach, was designed to provide beach nourishment and storm 

 surge protection for one of the most highly developed beach-front areas on 

 the Atlantic coast. Erosion, greatly accelerated by manmade structures and 

 modifications, had reduced the beach along this part of the barrier island to 

 the point where ocean waves often reached the many protective seawalls built 

 by hotel and private property owners. 



The project includes about 16.1 kilometers (10 miles) of shore between 

 Government Cut to the south and Bakers Haulover Inlet (see Figs. 6-23 and 

 6-24). The plan called for an initial placement of 10.3 million cubic meters 

 (13.5 million cubic yards) of beach-fill material. This placement provided a 

 dune 6 meters wide at 3.5 meters (11.5 feet) above MLW and a dry beach 55 

 meters (180 feet) wide at an elevation 3 meters (9 feet) above MLW, with nat- 

 ural slopes as shaped by the wave action. At Haulover Beach Park the plan 

 provided a level berm 15 meters wide at elevation 3 meters above MLW with 

 natural slopes. In addition, the project provides for periodic beach nourish- 

 ment to compensate for erosion losses during the first 10 years following the 

 initial construction. The nourishment requirements are estimated to be at the 

 annual rates of 161,300 cubic meters (211,000 cubic yards) of material. Nour- 

 ishment would be scheduled at 5-year intervals, or as needed. The estimated 

 project costs of about $67 million (1980 dollars), with the Federal share at 

 58.7 percent, include the 10-year beach nourishment. 



In July 1975, the city of Bal Harbor initiated the project by the place- 

 ment of 1,242,400 cubic meters (1,625,000) cubic yards) of beach fill over a 

 1.37-kilometer (0.85-mile) segment of shore fronting the city. In addition, 

 the south jetty of Bakers Haulover Inlet was extended to a total length of 

 about 245 meters (800 feet). 



Because of the project size, the remaining 15.53 kilometers (9.65 miles) 



6-32 



