Sand trapped by the updrift jetty was pumped to the downdrift beach 

 through a floating pipeline dredge. The dredging procedure used was 

 unique. The outer strip of the impounded beach was used to protect the 

 dredge from wave action during the initial phase. Land equipment exca- 

 vated a hole in the beach, and then a small pipeline dredge enlarged the 

 hole enough to permit a larger dredge to enter from the open sea. The 

 larger dredge completed the Phase 1 dredging, leaving a protective strip 

 of beach for the final operation. In dredging the barrier strip of beach, 

 cuts were made from the Phase 1 area to the mean lower low water line at 

 an angle of about 60 degrees to the shoreline. These diagonal cuts gave 

 the dredge more protection from waves than perpendicular cuts. 



Since it was necessary to close the dredge entrance channel to 

 prevent erosion of the protective barrier, water had to be pumped into 

 the Phase 1 dredging area to supply the dredge. This problem might have 

 been avoided had the proposed entry route from inside the harbor been 

 used and left open during Phase 1 dredging, rather than the entry route 

 from the open sea. (See Figure 6-45.) 



From August 1953 to June 1954, 2,033,000 cubic yards of sand were 

 bypassed to two downdrift feeder beaches through a discharge line sub- 

 merged across the harbor entrance. A survey indicated an erosion rate 

 downdrift from the harbor of about 2 million cubic yards from June 1955 

 to June 1956. Subsequent development of Channel Island Harbor, discussed 

 below, provided periodical nourishment to the downdrift beaches. 



6.522 Channel Islands Harbor, California . This harbor, designed to 

 shelter about 1,100 private small craft, was constructed about a mile 

 northwest of the entrance channel to Port Hueneme. (See Figure 6-46.) 



The design objectives of the littoral barrier were to trap nearly 

 all of the southward moving littoral drift, to prevent losses of drift 

 into the Hueneme Canyon, to prevent shoaling of the harbor entrance, 

 and to protect a floating dredge from waves. The sand bypassing opera- 

 tions transfered dredged sand across both the Channel Islands Harbor 

 entrance and the Port Hueneme entrance to the eroded shore downdrift 

 (southeast) of Port Hueneme (U.S. Army Engineer District, Los Angeles, 

 1957). The general plan is shown in Figure 6-46. 



The project consisted of an offshore breakwater and two entrance 

 jetties. The breakwater, 2,300 feet long and located at the 30-foot 



6-61 



