eddy current by the powerful warm Mozambique Current which flows south- 

 wards. It is of interest to note in passing that recent surveys have 

 indicated that this current, generally believed to be in the region of 

 three to four miles offshore, varies considerably in its distance from 

 the coast, and on a recent occasion has been found no nearer than thirty 

 miles off-shore opposite the Bluff Whaling Station. The littoral current 

 referred to travels up the coast in a north-easterly direction and is 

 greatly influenced by the prevailing winds. Assisted by the obliquity 

 of wave action, it carries large quantities of sand in suspension and 

 there is no doubt that, in general, it causes a littoral drift of the 

 sand supply from the south to move up the coast. 



BFPBCT OP PREVAILING WINES 



The prevailing winds of Durban are north-east and north-north-east 

 on the one hand, and south-west and south- south-west on the other, with 

 periods of calm averaging 21% of the time. These winds have a marked 

 effect upon the wave action and the consequent aggravation of the sand 

 movement. During severe north-easterly winds, for example, the combina- 

 tion of these two natural erosive forces can become so strong as to cause 

 serious depletion of the beach within a very brief period - it is not a 

 rare occurrence for over 100,000 cubic yards of sand to be lost from the 

 beach within a few days during such occasions, particularly when in con- 

 junction with the equinoctial tides. Frequently, the bulk of the 'lost* 

 sand appears to be deposited in off-shore banks parallel to the shore and 

 about 200 to 300 yards out. Some of this material, together with some 

 bed sand, is returned to its original position under the influence of 

 south-westerly winds, due to the fact that the waves on these occasions 

 affect the seabed to a greater degree, and the sand is brought into sus- 

 pension and moved shoreward by the current, but in general the losses far 

 exceed the later accretion. 



EFFORTS TO COMBAT EROSION 



Considerable investigation has been directed to the "near shore" area 

 of the beaches, as it is clear that the maximum movement of the sand takes 

 place within this area. It is therefore of interest to examine the posi- 

 tions of the various fathom lines under the different conditions which have 

 existed over the period under review. In order to appreciate the circum- 

 stances, however, it will be necessary to give a very brief resume* of the 

 steps which were taken by the Durban Corporation to combat the serious 

 erosion which took place prior to 1938. Several consulting engineers were 

 engaged, and there was unanimity amongst all as to the cause of the erosion, 

 which was agreed to be prolonged dredging in the vicinity of the harbour 

 entrance, and also as to the cure, which was the replenishment of the 

 beaches by artificial means. It was on the method that disagreement arose, 

 and the Council finally adopted the scheme whereby the Railways Adminis- 

 tration supplied the sand for replenishment from its dredgers, delivery 



