Noting this possibility, Bourodimos (1968) used a dynamic calibration 

 technique for water level probes, but did not report the magnitude of 

 difference between dynamic and static calibrations. Dynamic measurement 

 errors were not investigated in the present study, so the measured wave- 

 forms have been treated as qualitative data. 



The major reported data are peak water levels above SWL, and do not 

 include the uncertain accuracy of the instantaneous water level measure- 

 ments. Because peak crest flow varies rather slowly, dynamic measurement 

 errors are unimportant and the static calibration ensures accurate 

 measurement of peak water level. The only major wave-gaging problem in 

 these tests was encountered in making measurements with the strip gages 

 (Fig. A-2, d and e) , which were subject to a gain of sensitivity in 

 time. Figure A- 3 shows wave, crest, and trough dimensions measured by 

 the incident gage (Fig. A-2, a) and by the strip gage on the pile in one 

 test. This test lasted about 3 hours and the data were collected pro- 

 ceeding counterclockwise from a = 0°. Gage measurements show that the 

 incident wave action did not change during the test, but the strip gage 

 recorded increasing trough and crest dimensions as the test proceeded. 

 The increase in crest height may be due to wetting of the adhesive 

 attaching the conductive strips to the pile face, but the trough measure- 

 ments are puzzling. This problem led to use of the direct methods of 

 peak water measurement at a circular pile. 



a. Dimensions of Incident Wove. 



b.Wove Dimensions on Surfoce of Circular Pile. 



Wave Height 

 Crest Heigtit 

 Trougti Deptti 



Figure A-3. Measurement drift shown by strip gage on the 3-inch 

 circular pile in unchanging incident wave action. 



76 



