these tests, a trap giving an efficiency close to 100 percent has been 

 developed. This instrument is being tested under field conditions in 

 a 30 x 30-foot sand area. In addition, equipment for studying sediment 

 movement by wave action was revised, and calibration of the apparatus 

 was completed, prior to initiation of further tests. 



IV. University of California, Contract DA-49-055-eng-44. Laboratory 

 Study of Wave Refraction . 



Laboratory experiments have been made on the reflection and energy 

 dissipation characteristics of a solitary wave at a sloping wall at an 

 oblique incidence. These laboratory studies have been largely completed 

 and a report is in preparation. Some theoretical work has been done on 

 an exact second order theory for cnoidal and solitary waves. The results 

 appear to agree more favorably with laboratory measurements of several 

 wave characteristics than is the case with other theoretical results. 



V. Agricultural and Mechanical College of Texas, Contracts DA-49-055- 

 eng-56-4 and 58-9. Estimation of Hurricane Surges . 



Additional work was done on the research problem in Narragansett 

 Bay (eng-56-4). This work included analysis of the surge forcing 

 functions for the various hurricanes, which involves an analysis of the 

 alongshore as well as the onshore components of wind and wind stress. 

 A revised program for surge calculations on the computer was compiled. 

 This program incorporates astronomical tide with the surge by a suitable 

 input condition at the edge of the shelf. Numerical stability for the 

 bay calculations is obtained by use of a schematic made up of subchannels 

 with identical travel times (for a free surge), and by the incorporation 

 of a filter at each step to subdue any erratic behavior. The calcula- 

 tions also involve taking into account the variation of water storage 

 area within the bay as a function of water elevation, thus preventing 

 overestimates of the peak surge at Providence and other points near the 

 head of the bay where flooding of low-lying land areas occurs. Computa- 

 tions for observed and design conditions are under way. Computational 

 methods previously developed for determining storm surge estimates in 

 the New York Harbor entrance area (eng-58-9) have been used to make 

 predictions for hurricane water levels in that area. A report 

 summarizing this work "The Prediction of Hurricane Storm Tides in New 

 York Bay" will be published in August 1960 as Technical Memorandum No. 

 120 of the Board. This report describes the effort made to correlate 

 storm surges in New York Bay with the meteorological characteristics of 

 the storms producing them, and thus to predict the nature of the storm 

 surge resulting from a hypothetical design hurricane. The method used 

 is largely empirical, but has theoretical guidance. Therefore, though 

 the constants involved apply only to the specific areas studied, the 

 general method and procedure may well have more general application. 



VI. Dr. W. C. Krumbein (Consultant). Study of Beach Sampling Methods . 



Design of computer program to study the application of computing 

 machine methods to the study of factors influencing beach characteristics 



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