T.M. No. 120-A - Apr! I 1961 



Discussion of Technical Memorandum No. 120, "The Prediction of 

 Hurricane Storm-Tides in New York Bay" (and Closure by Author) 

 by D. L. Harris and B. W. Wilson 



The author has carefully examined the methods and prediction 

 formula for hurricane storm-tides presented by Dr, Wilson in BEB 

 T.I^. No. 120, and discusses certain points which he believes limit 

 its general applicability for storms other than those used in its 

 development. Mr. Harris has independently applied Wilson's formula 

 to Hurricane Hazel (1954) and has presented an alternative prediction 

 formula. Wilson amplified the points raised by Harris and makes 

 further explanation for their treatment in his own prediction tormula 

 noting shortcomings in the Harris approach which in Wilson's opinion 

 indicate the Wilson formula to be more versatile. 



T.M. No. 121 - September I960 



Development and Tests of a Radioactive Sediment Density Probe 

 by J. M. Caldwel I 



The development, calibration, and laboratory and field testing 

 of an instrument for in-pi ace determination of sediment density is 

 described. The device encased in a submersible probe and utilizing 

 3 millicuries of radium to detect reflected gamma rays transmits a 

 preamplified signal through a 75-foot cable to a scaler, the signal 

 being correlated to the density of the sediment-fluid mixture. The 

 probe senses the in-place bulk density of sediment surrounding the 

 probe over a sphere of material of about I -foot radius centered on 

 the probe. Evidence is presented that this device is an accurate 

 and practical tool for use in the field, and that its accuracy is 

 greater and costs less than for other methods presently in use. 



T.M. No. 122 - November I960 



Effects of Reefs and Bottom Slopes on Wind Set-up in Shallow Water 

 by E. G. Tickner 



Wind tides in shallow water were studied in a laboratory channel 

 with a reef, with various widths of openings, located near the center 

 of the channel and with various slopes of the channel bottom other 

 than horizontal. The reef increased the setup over a smooth bottom 

 condition by a factor of two for a solid reef and somewhat less than 

 this if the reef had an opening in it. The cross-sectional integra- 

 tion procedure adequately describes the surface profile for the 

 sloping bottom, while the estimated setup assuming a constant depth 

 equal to the deepest part underestimates the actual setup as much 

 as 2.75. 



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