The underwater work with reference rods has indicated changes in 
the bottom level in excess of 2 feet in shallow water; changes in water 
deeper than 30 feet have been very slight. 
The observation and measurement of ripples has been extended to 
include two coarse sand areas. The large size of the ripples in coarse 
sand permits direct observation of grain motion and selective sampling 
of sand from ripple crest and trough. Generally sand from the ripple 
crest is slightly coarser, better sorted, «nd skewed more toward coarser 
particle sizes than that from adjacent troughs. 
Between 30 November and 15 December a submarine slide took place in 
the Sumner Branch and South Branch of Scripps Submarine Canyon. The 
slide was. first reported by divers and was confirmed by an echo=sounding 
survey which showed that the maximum change was a deepening of 9 feet. 
The divers had reported larger changes but these were in the narrow 
gorge, where echo-sounding is inaccurate. Stakes have been driven into 
the canyon walls which will allow comparative measurements to the canyon 
floor. 
Vie The Agricultural and Mechanical College of Texas, Contract No. 
DA-0-055-eng-16, Quarterly Report for period ending 3] January 195h. 
le Field Operations, Field operations were continued at the Sun 
Oil Pier at Caplen,Texas, Simultaneous 20-minute records being taken 
twice daily at both shoreward and seaward end of the pier. 
A third recorder has been installed temporarily on a Magnolia Oil 
platform south of Morgan City, Louisiana, and records are being taken 
periodically. The mean water depth at this site is 0 feet. 
The analysis of all wave records obtained at Pure Oil Structures A 
and B has essentially been completed. The analysis of wave records ob- 
tained at the Sun Oil Pier and Magnolia platform is in progress. 
2. Theoretical Investigations. Computations involving the combina- 
tions of wave generation and wave energy loss due to bottom friction have 
been completed for the case of a shallow bottom of constant depth. 
Computations for a bottom of constant slope have continued. 
VI. New York University, Contract No. DA-)9-055-eng-32. 
Work was continued on the development, design, and manufacture 
of a spectrum analyser for wave records, and on the statistical analysis 
of hindcast wave data along the Atlantic Coast obtained by the Neumann- 
Pierson methods. In addition, a report "On Ocean Wave Spectra and a 
New Method of Forecasting Wind-Generated Sea" by Gerherd Neumann was 
published as Technical Memorandum Number 3 of the Beach Erosion Board. 
11 
