1902. 



FORESTRY AND IRRIGATION. 



441 



agricultural countries in the world, with 

 crops superior to any raised elsewhere. 

 This is mainly due to the magnificent 

 and untiring efforts of the English engi- 

 neers in charge of irrigation and similar 

 work. 



Probably the most important of these 

 irrigation works is the Nile Reservoir 

 Dam at Assuan, at the first cataract of 

 the Nile. This is the largest dam of 

 its kind in the world, being i}( miles 

 long. It impounds the water at the 

 period of high tide and stores it for the 

 period of low water. It is a sluice dam, 

 as shown in the frontispiece of this is- 

 sue, which is made from an official 

 Eg3"ptian government photograph, fur- 

 nished by Mr. Means. An interesting 

 fact concerning its construction is that 

 it is 35 feet lower than its intended 

 height, though the foundations have 

 been made to support the additional 

 masonry should it ever be constructed. 

 This decreases the dam's capacit}' just 

 one-half ; the reason exists in the tem- 

 ple of Philae on an island up stream, 

 which would be submerged if the dam 

 were carried to its platmed height. As 

 this temple is one of the most interest- 

 ing and best preserved in the country, 

 its complete annual submersion was not 

 to be tolerated. One engineer wanted 



to build the island, temple and all, tO' 

 the required height, while another sug- 

 gested carrying it away bodih' to some 

 other place. As it is, the dam remains 

 one-half as useful as it might be if it 

 were not for the temple. As it stands 

 now, the dam has a capacit}^ of 35,000,- 

 000,000 cubic feet of water, held at a 

 height of 48 feet above the zero of the 

 Assuan gage. The water impounded 

 will suffice for the irrigation of 300,000 

 acres of cotton and sugar cane, and will 

 be worth $50,000,000 to the country. 

 The dam, completed to its full height, 

 will cost about $8,750,000, and doubling 

 its present capacity this will mean $125,- 

 000 for 1, 000, 000, 000 cubic feet of water, 

 or, allowing for evaporation, $150,000 

 per 1,000,000 cubic feet. 



On December 8 this dam will be dedi- 

 cated with considerable ceremony, in 

 the presence of the invited representa- 

 tives of many nations. Forestry and 

 Irrigation will present a full account 

 of the dam and its value in a subsequent 

 issue, the article being one of a series 

 which Mr. Means will write for this 

 magazine on the irrigation works of 

 the countries he visited, with reference 

 to their significance and applicability 

 to similar conditions in the United 

 States. 



ROW OF HARDY CATALP.A, TREES ON THE GROUNDS OF MR. GEO. A. ROOT, TOPEKA, KANS.\S. 



TREES EIGHTEEN YE.A.RS OLD, HEIGHT 30 FEET, AND DIAMETER TWO FEET 



FROM THE GROUND lO INCHES. PHOTO REPRODUCED THROUGH 



COURTESY OF MR. GEO. W. TINCHER. 



