OBSERVATIONS OF TRANSFORMATION OF SHALLOW WATER WAVES OFF THE OGATA COAST

Ten-minute simultaneous wave records have been obtained in shallow water off theOgata Coast by six step-resistance type wave gauges set along a long pier at depths ofm and at a tower at a depth of 25 m. This paper presents the results of waveobservations analyzed both by the significant wave and the wave spectrum method.The main results obtained are as follows: 1) Though the relationship between bottomfriction factors and wave Reynolds numbers in shallow water off some Japanese coastsobtained by Iwagaki.Kakinuma (1966) are relatively reasonable at offshore side stations, the calculated values of bottom friction factors are much greater at onshore side stations;2) The interactions between spectral component waves at onshore side stations differfrom at offshore side stations in strength and behaviour; 3) The significant wave heightsat W-5 are greater than those at W-4 when those are comparatively high.