IRRIGATION AND T>KA1NAG&. 155 



there is the Esneh barrage under construction, and the 

 Assiout barrage which, closed in a bad flood, saved an 

 enormous area of basin land from imperfect filling. 



The Barrage 12 miles below Cairo sends a supply down 

 the three great canals which irrigate the whole Delta. 



The Zifta barrage is also an important work. The early 

 red water of the flood was largely wasted into the sea 

 down the Damietta and Rosetta branches of the Nile. 

 The discharge at Cairo, which is only 550 cubic metres 

 per second about the 5th of July, is 1000 cubic metres 

 by the 20th and 1800 cubic metres by the 31st of that 

 month. The Zifta barrage arrests and distributes that 

 early flood passing down the Damietta branch, and a 

 similar barrage in the Rosetta branch will perform the 

 same function there. 



If water can be had by the loth of July for maize and 

 flood rice sowing, Government would be perfectly justified 

 in publishing a decree permanently forbidding all rice and 

 maize cultivation before that date. These are properly 

 Nili crops, but of recent years the abuse has arisen of 

 using for these other crops' water, which should be devoted 

 to cotton only. The Nile reservoir has after all a limited 

 capacity, and other storage schemes, either in the great 

 Central African lakes, in Lake Tsana, or in the bed of the 

 White Nile itself are under consideration. But if the water 

 is not unnecessarily used for other crops it will suffice for 

 all the cotton which can be grown for some years to come. 



Drainage is almost as necessary as irrigation, and that 

 for various reasons. It permits the passage of air into 

 the soil to oxidise and break up plant food, and to render 

 harmf ul matters innocuous. It allows the filtering through 

 of fresh water to remove noxious salts. It facilitates the 

 penetration of plant roots, and thus increases their range 



