458 



Tides in Estuaries 



This increasing asymmetry can only occur when the velocity with which 

 the peak of the tide wave (high water) travels differs from the velocity of the 

 foot of the wave (low water). Table 74 gives for the same rivers these velocities 



o Where current reverses 



Cuxhaven 



Gluckstadt 



Brunshousen 



Schulou 



Nienstedten 



Hamburg 



6 8 10 12 2 4 6 8 10 12 2 4 6 8 10 12 2 4 6 

 Time, hr 



Fig. 193. Tide curves in the "River tide zone" of the Elbe; o indicates slack water. Height 



scale about 1 : 170. 



according to the same sources. In fact, they are different according to the 

 depth of the rivers, but the high-water values are everywhere considerably 



Table 73. Asymmetry of the flood wave in estuaries 



