XII. Beach Erosion Board Staff. 



(a) Wave Forces on Piles 



Numerous measurements have been made of the wave forces on a 

 vertical 12-inch pile with a 3-foot sensitive (instrumented) section. 

 The pile is cantilevered from a frame at the top of the tank and may 

 be raised or lowered to place the 3-foot sensitive section at various 

 heights. Waves with periods ranging from 5 to 16 seconds, and heights 

 ranging from 2 to 6 feet have been tested in water depths ranging from 

 7 to 15 feet. The forces on the 3-foot sensitive section ranged from 

 20 to 100 pounds for nonbreaking waves, and breaking waves produced 

 forces of short duration as high as 1,000 pounds. 



(b) Wave Run-up 



Testing of eight smooth slopes ranging in steepness from 1 on 30 

 to a vertical wall has been completed and most of these slopes have 

 been tested for the effect of roughness on wave run-up by roughening 

 the slopes with five sand sizes ranging from 0.2 to 10 millimeters in 

 median diameter. Also, most of the slopes have been tested for the 

 effect of permeability op wave run-up for the same sjinds used in the 

 roughness tests. The data show that slope roughness and permeability 

 reduce wave run-up considerably below that observed for smooth slopes. 



(c) Study of Sand Bypassing Operation at Port Hueneme 



As a continuation of the observational program, a survey of the 

 area was made in May 1957. The data taken before, during and after the 

 Port Hueneme dredging to June 1955 have been analyzed and the report 

 was published as Technical Memorandum No. 92. Computations to establish 

 the volumetric changes between June 1955 and June 1956 have been made and 

 according to these computations, over 2 million cubic yards of material 

 was lost from downcoast beaches while the upcoast area gained in the 

 order of 200,000 cubic yards of material. It is recognized that the 

 major portion of the material from updrift is shunted into Hueneme 

 Submarine Canyon by the west jetty and lost from the survey record. 



(d) Laboratory Study of Effects of Groin Field on Littoral 

 Drift Passing Field 



Preliminary tests were made in the Shore Processes Test Basin to 

 establish an equilibrium profile on which the groins will be placed. 

 Installation of a new trapping and sand-moving system using eductors 

 to transfer the trapped sand to the feeder beach area was completed. 

 The new system has been used in several tests and works very well, 



(e) Measurement of Suspended Material in Laboratory Wave Tanks 



Sampling has been continued in the Shore Processes Test Basin 

 (groin study) and the large outdoor wave tank. Analysis of the data is 

 in progress and a draft of the report is being prepared. 



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