THE SEA OF AZOV 



467 



and more form 50-2 per cent of the total area. Hence the shallows (less than 

 5 m) occupy only 7 per cent of the Sea. 



As one moves farther into the Gulf of Taganrog its depth decreases from 

 9 to 8 m in the central part of its western half. The greatest part of this half of 



ISOBATH 5m 

 ■ ISOBATH 10m 



Fig . 222. Chart of Sea of Azov with the 5 and 10 m isobaths (Knipovitch). 



the Gulf is 5 to 7 m deep, and the 4 m isobath approaches close to the coast. 

 In the eastern part of the Sea, by contrast, large areas are occupied by shallow 

 banks 2 to 3 m deep or less. The most eastern sector of the Gulf is a sub- 

 marine delta of the river Don, with troughs — the continuation of the arms of 

 the delta — which are divided by shoals. 53-6 per cent of the total area of the 

 Gulf of Taganrog is 5 m deep or less. 



Currents 



Owing to the shallowness of the Sea, its water is in a state of perpetual hori- 

 zontal motion and under the effect of the winds ; various multiform systems 

 of irregular currents are thus created. N. M. Knipovitch (1932), however, 

 considers that there are many indications of the existence of some constant 

 system of circular cyclonic current along the shores, circling round the central, 

 deeper part of the Sea. 



Fluctuations of water-level and water-balance 



The water-level of the Sea of Azov and its various parts undergoes con- 

 siderable fluctuations as a result of spring floods, of rainfall, of summer 



