IRRIGATION AND DRAIN A GK 151 



with the red water rich in silt. The value of basin land 

 depends on the amount of silt deposited, and consequently 

 basins or parts of basins which are nearest the source of: 

 supply are most valuable as they receive most silt. 

 Beginning with an appreciable rise in July, the Nile 

 continues its rise in August till it attains the maximum 

 which is maintained during the first ten days of September, 

 after which it begins to fall less rapidly than it rose. 

 The basins are grouped into systems which are fed by 

 large canals taking water directly from the Nile. 



The objects of the Irrigation Engineers are to fill the 

 basins as early as possible and to a sufficient depth with 

 rich silt-laden water, to leave the water 30-40 days to 

 deposit its silt and then to drain it back into the Nile. 

 The cultivators follow the retreating water, as it lays bare 

 the basins, with their sowing of winter crops. If the 

 Nile flood is a poor one there is difficulty in filling the 

 basins. In former years under such circumstances large 

 areas remained without water, entailing most severe loss 

 on cultivators, and remission of land-tax by the Govern- 

 ment. Much has been done in the past fifteen years by 

 remodelling and improving the basin system to greatly 

 mitigate the evils of a low flood, and this so successfully 

 that even in recent bad floods the unirrigated areas have 

 been trifling. Instead of draining the basins directly into 

 the Nile, by a judicious arrangement of canals the water 

 from the higher basins, which were first filled, is passed 

 into the lower basins which had only received partial 

 filling and thus the latter in bad years can be saved from 

 drought, although they may only receive clear water from 

 which the upper basins have abstracted the silt. 



