Long Waves in Canals and Standing Waves in Closed Basins 187 

 Table 25. Logarithmic decrements of seiches in lakes 



(According to Endros) 



damping occurs in lakes composed of basins which are connected with each 

 other by a narrow canal. This is the case with the Waginger-Tachinger See, 

 the Konigssee, and others. Another group which has a great damping factor 

 is the shallow lakes, like the Lake Balaton, the Kurisches Haff, etc. It seems, 

 on the whole, that every great disturbance in the morphology of the basin 

 is accompanied by an increased damping of the seiches; this increase can 

 take such proportions that the variation of the water level comes very close 

 to being aperiodical. 

 (b) Oscillations in Bays 



It has been clearly proven from the tide-gauge registrations that all ocean 

 from the smallest to the largest, execute oscillations with a nodal line at the 

 opening of the bay. These "disturbances" in the tidal curves are so frequent 

 that smooth tidal curves are very rare. Honda, Terada, Yoshida and 

 Isitani (1908) have reproduced in scale models the oscillations as they 

 occur in nature in the bays along the Japanese coast. Figure 79 gives as an 



100- 



o J 



6 12 © 



Fig. 79. Tide curves in the Bay of Hakodate and oscillations of short period in the bay. 



example tidal curves of the Bay of Hakodate on which the short-period 

 oscillations of sea level in the bay are superimposed. The principal seiches 



