120 



area to be undertaken, known as the Central Gharbia drainage 

 area. The land is divided into categories : good, medium, and 

 poor land under cultivation, barren land, land under reclama- 

 tion, and land on which at the time of survey there was stand- 

 ing water. 



A check was put on the field surveyors by the determination 

 of the salt-content of large numbers of soil samples taken as 

 the work proceeded. It is well recognized that the presence 

 or absence of salt is the principal determining factor in the 

 fertility of the Delta land. The results showed that the fertility 

 is a close approximation to a salt survey, the good land con- 

 taining on the average o'3 per cent., the medium 0*5 per cent., 

 and the poor land 0*8 per cent. The barren land may contain 

 up to as much as 25 per cent, of salt. 



The close dependence of the fertility on the altitude above 

 sea-level, or in other words on the amount of natural drain- 

 age, is shown by a comparison of the fertility map with a 

 contoured map of the same area. 



THE WATER SUPPLY OF EGYPT, 19131914. 



By B. F. E. KEELING, M.A., 



Director of Physical Services, Survey Department, Ministry 

 of Finance, Egypt. 



[ABSTRACT.] 



The flooid of 1913 was the lowest recorded for over one 

 hundred years. A general account is given of the rainfall in 

 the areas from which the Nile draws its supply, and of the 

 methods by which the water is utilized in Egypt, with the two 

 main divisions of basin and perennial irrigation, the limits of 

 which are shown on a map. During winter there is always 

 sufficient water for the perennially irrigated tracts, and the 

 principal factor in irrigation is the height to which the Nile has 

 risen, enabling more or less of the basin tracts to receive water. 

 In summer there is often difficulty in providing the perennially 

 irrigated areas with sufficient water, and it is then the quantity 

 of water which is the controlling factor. 



In 1913 the flood-level at Aswan was 2\ metres below normal, 

 and \\ metre below that of any previous year since the occu- 

 pation. The effect of this on the irrigation of Upper Egypt, 

 and the function of the Esna Barrage in providing water to 

 basins which otherwise would have been left dry, are explained. 



The low flood was naturally followed by a very bad supply 

 during the early summer of 1914. The natural supply reaching 



