characteristics and stability has been completed. Field data obtained at 

 Mission Bay, California in 1950 were utilized in the study and found to 

 be too few and too similar to develop clearly defined relationships. A 

 method by which such data may be treated has been determined as a result 

 of this study, and the design of a possible field test to acquire all 

 necessary data is underway. The results of the computer study are being 

 summarized and will be published as a technical memorandum in the latter 

 part of 1961. 



VII. Beach Erosion Board Laboratory . 



(a) Wave Forces on Structures. 



Analysis was continued on the wave force data obtained in the large 

 wave tank on a vertical 12- inch diameter pile. This work has been pointed 

 particularly towards the phase relationship of the water elevation, water 

 velocity, and wave force with the passage of the waves. A report on this 

 work is under preparation. A new section on wave forces on piles was pre- 

 pared for inclusion in Beach Erosion Board Technical Report No. 4, making 

 use of higher order approximations of wave characteristics. A somewhat 

 more comprehensive treatment of this work is being put into report form. 



(b) Wave Run-up. 



Additional large-scale data involving waves up to 3.5 feet in height 

 were gathered on a 1 on 1-1/2 riprap protected slope using 160-pound rock 

 in an attempt to determine possible existence of a scale effect. Calibra- 

 tion tests for this tank were essentially completed, to enable accurate 

 determination of the waves acting on the structure. Data on effect of 

 scale in determination of prototype wave run-up from small-scale model 

 tests on smooth stones were analyzed, and a correction curve prepared for 

 inclusion in the new edition of Beach Erosion Board Technical Report No. 4. 

 These data were also combined with run-up data, resulting in a corrected 

 run-up curve for specific use with normal design waves in inland reservoirs, 

 This curve is included in a report "Freeboard Allowances for Wind-Generated 

 Waves in Inland Reservoirs" presented before the American Society of Civil 

 Engineers, and submitted to them for publication. 



(c) Study of Sand Bypassing Operations. 



Efforts were continued to collect all available data on sand by- 

 passing operations (past, present, or planned) for correlation and study. 

 The hydrographic survey data obtained in the Port Hueneme area in June 

 1959 are now being analyzed. A field observation program was initiated in 

 the vicinity of the new Ventura County Harbor, California, in which an off- 

 shore breakwater (parallel to the shore) forms a protected area serving as 

 a sand trap. Sand deposited in this protected area is to be dredged and 

 bypassed to the downdrift side of Port Hueneme. Wave gages for this study 

 were installed, and tape recorders for use in obtaining material for wave 



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