5.6 sec). '^' The exception occurred when the beach eroded to expose the 



end wall of the tank in Cases 100 and 110. In these tests, reflection was 



observed to increase as the scour depth increased to expose more of the end 



wall. 



Water temperature 



20. Water temperature in the tank most likely exhibited seasonal varia- 

 tions since it was not controlled and the tank was not sheltered. Although 

 temperature was not measured during the experiment (except for one case), it 

 is possible to obtain estimates of the water temperature for each of the 

 respective cases (Appendix A). 



Recording of Data 



21. During the experiments, profile survey measurements, wave height, 

 and other information were recorded in logbooks. Measured profiles were 

 plotted soon after each run was completed to determine if the profile had 

 achieved a near-equilibrium shape, i.e., if further changes would be small. 

 Many of the plots were digitized in 1979 and the data placed on a nine-track 

 magnetic tape for replotting by computer.-* 



22. It is believed that there were seven logbooks holding the data 

 from all LWT experiments performed with the 0.22- and 0.40-mm sands. These 

 logbooks also contained data for similar experiments concurrently performed in 

 small tanks to investigate scale effects. However, only five logbooks 



were located in the course of preparing this report. In the present work, 

 those profile surveys not on the magnetic tape but appearing in the available 

 logbooks were entered into computer files in the same format as the data digi- 

 tized in 1979. The format is described in Appendix C. 



23. Through a combination of the three available data sources (log- 

 books, hand-drawn plots made during the course of the experiments, and the 

 magnetic tape), almost all of the known profile surveys were recovered. Plots 

 generated from the 1979 tape were visually compared to the original plots in 

 order to verify and correct the data files. Thus, essentially all profile 

 change data sets from the movable-bed experiments performed in the LWT in 

 1956-1957 and 1962 have been recovered, digitized, and verified. 



24. A compilation of the associated wave data was made in the prepa- 

 ration of this report. There were three primary sources of data on the 



15 



