T.M. No. 90 - September 1956 



Relative Efficiency of Beach Sampling Methods by W. C. Krumbein 

 and H. A. Slack 



This paper is an extension of the work reported in Technical 

 Memorandum No. 50 in that it presents the results of several sampling 

 experiments designed to show more explicitly how estimates of certain 

 beach material properties may vary as a result of the sampling plan 

 adopted. A number of sampling designs applied to areas along Lake 

 Michigan near Waukegan, Illinois, and at Ocean Beach, Maryland, are 

 compared to indicate some of the factors involved in beach sampling 

 for different purposes. 



T.M. No. 91 - November 1956 



Changes in Configuration of Point Reyes Beach, California 1955-1956 

 by Parker D. Trask 



This report continues the study in T.M. No. 65. Surveys were 

 made at 8 intervals between August 1955 and June 1956; variations 

 in sediment characteristics were investigated and correlated with 

 changes in cusp formations and cut-and-fill on the beach. 



T.M. No. 92 - March 1957 



Sand Bypassing at Port Hueneme, California by Rudolph P. Savage 



Discussion of a novel method of bypassing sand from an accreted 

 area updrift of a jetty to an eroding downdrift shore Is presented. 

 The method involved first the dredging of a large lagoon behind the 

 beach, leaving a barrier to serve as protection for the dredge, and 

 then dredging cuts through the barrier. Results of the operation 

 as indicated by periodic surveys after its completion are presented, 

 and in general indicate the method to be successful. Modifications 

 are suggested should similar operations be planned for the future. 



T.M. No. 95 - February 1957 



Modification of the Quadratic Bottom-Stress Law for Turbulent 

 Channel Flow in the Presence of Surface Wind-Stress by R. 0. Re Id 



A generalized formula for velocity profile and bottom stress is 

 derived which. takes the influence of surface stress into account. 

 In general, the effect of the wind stress is such that, for a given 

 current, the effective resistance to the flow is reduced for a 

 following wind and increased for an opposing wind, relatived to the 

 resistance which exists In the absence of the surface stress. The 

 steady state case with zero mean flow is treated as a special case 

 of the general theory, and the ratio between bottom stress and sur- 

 face stress is found to be independent upon the ratio of depth to 

 bottom roughness, and generally less than 0.1. 



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