supported by a 30-foot movable boom. The discharge line is 1,750 feet 

 long, and is made of steel pipe with a 1/2-inch wall thickness, except 

 for an 800-foot section of wire-reinforced rubber hose submerged line 

 that crosses the navigation channel. This section can be removed during 

 channel maintenance. Safety features were installed to reduce the possi- 

 bility of clogging the submerged discharge line. 



The plant began operating in August, 1958. It was estimated that 

 71,400 cubic yards of sand were bypassed in 451 hours of operation during 

 8 months, or a rate of about 100,000 cubic yards per year, almost half of 

 the estimated annual littoral transport rate. 



6.52 FLOATING BYPASSING PLANTS 



All four types of littoral barriers (Figure 6-42) have used float- 

 ing plants for harbor and inlet improvements. Floating bypassing plant 

 operations have been used at the following places: 



TYPE I 

 Port Hueneme, California 



TYPE II 

 Channel Islands Harbor, California 

 Ventura Marina, California 



TYPE III 

 Fire Island Inlet, New York 

 Santa Barbara, California 

 Oceanside Harbor, California 



TYPE IV 

 Hillsboro Inlet, Florida 

 Masonboro Inlet, North Carolina 

 Ponce de Leon Inlet, Florida 

 East Pass, Florida 

 Perdido Pass, Alabama 



6.521 Port Hueneme, California. (Savage, 1957) . This harbor is about 7 

 miles south-southeast of the mouth of the Santa Clara River. The harbor, 

 constructed in 1940, was acquired by the U.S. Navy in 1942. The 35-foot- 

 deep entrance channel is protected by two converging rubble-mound jetties. 

 (See Figure 6-45.) Littoral drift moves southeast at a rate estimated 

 between 800,000 and 1,200,000 cubic yards a year. (Herron, 1960.) 

 Although the west jetty impounded a substantial amount of sand, its 

 greatest effect was to divert the sand into the Hueneme Canyon, thus pre- 

 venting this material from reaching the shores southeast of Port Hueneme. 

 Before harbor construction, the downdrift shore was exceptionally stable. 

 After construction, the rate of erosion was about 1,200,000 cubic yards 

 per year from 1940 to 1953. In 1953 an emergency project was started at 

 this harbor to reduce downdrift erosion by nourishing the downdrift beaches. 



6-59 



