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Egypt, not to mention the water which is necessary for new plantations. This fact has been borne in mind for many years past, and Sir William Garstin has been giving his most earnest attention to the finding of some means whereby the lands which are at present waste may be brought under cultivation. Speaking broadly, the cultivated land in Egypt is now producing nearly all it is capable of, and as the revenue of the country depends upon agricultural prosperity, little more revenue is to be expected until more land is brought under irrigation. As Lord Milner says, “In Egypt prosperity and water go hand in hand.” After much thought the English engineers of the Irrigation Department decided that the only way to provide more water, and so increase the revenue, was to build a huge reservoir, preferably at Aswân. Statistics prepared by Sir W. Willcocks (op. cit., p. 428), show that about one-third of the land in Egypt is undeveloped, that nearly the whole of this undeveloped land lies in the perennially irrigated tracts, and that the summer supply of water is not sufficient for perennial irrigation. There are about 2,000,000 acres of waste land in Egypt, and to redeem these and water all the cultivable land, 6,000,000,000 cubic metres of water will be required.
The proposal to build the Aswân Reservoir was opposed violently by certain irresponsible archæologists, because, they declared that, according to the original plans, the beautiful temple at Phile would be submerged annually, and finally would be destroyed by the water. Instead of holding up the water at a level of 114 metres above mean sea level, Sir W. Garstin reduced the level to 106 metres, which satisfied most people ; but Sir W. Willcocks thinks (p. 437) that “this action of the archæologists has hurt the reservoir and will not in the end save the temple.” After some difficulties as to ways and means, Messrs. Aird and Co. signed a contract with the Egyptian Government, undertaking to build the Aswân Dam and supplementary works for the sum of £2,000,000 ; the works were to be completed in 1903, and Messrs. Aird were to receive no payment until that date, when the debt was to be paid off in 30 half-yearly annuities of £78,613. The canals and drains, which form an important part of the scheme, were to be made within the five years in which Messrs. Aird were building the dam, and were to cost about £2,000,000 sterling more. It was calculated that the revenues of the country would be increased by about £2,750,000 when the works were completed, and while they were in progress Egypt paid nothing. The actual cost of the Aswân Dam and the Asyût Barrage was £E.3,439,864.
The Aswan Dam stands in the First Cataract, a few miles south of Aswân. It is designed to hold up water to a level of 106 metres above mean sea level, or rather more than 20 metres above the low-water level of the Nile at site. Its total length is 2,185 yards, with a width at crest of 26-4 feet. The width of the base at the deepest portion is 90 feet, and the height of the work at the deepest spot is 100 feet. The dam is pierced by 180 openings, or under-sluices, of which 140 are 23'1 feet by 6.6 feet, and 40 are 18'2 feet by 6.6 feet, provided with gates. Four locks have been built, and a navigation channel made on the west of the river. It has been decided to raise the Aswân Dam, and when this has been done the water will be held up to a height of 112 metres, instead of 106 metres as at present.
Early in 1905 a number of sensational reports were spread relative to the safety of the Aswan Dam. These were no doubt due to an entire misconception of the true meaning of a report submitted on March u by Sir William Garstin to the Egyptian Council of Ministers. Sir William then stated that circumstances had arisen inducing him to modify the conclusion that the Aswân Dam should be raised without delay. The reasons for this decision were that it was desirable, before adding to the height of the structure, to adopt measures for protecting the downstream bed of the river from erosion by water flowing through the sluices of the Dam, and also to consider carefully the views expressed in a recent paper by Prof. Karl Pearson and Mr. I. W. Atcherley on “Some Disregarded Points in the Stability of Masonry Dams.” The authors of this paper are mathematicians whose opinions cannot be lightly discussed, but we may say at once that no abstract theory can sweep away, or in any way disturb, the solid basis that secures the safety of the Aswân Dam. It will be remembered that when Sir W. Willcocks first prepared drawings for a dam, in 1890, it was intended that water should be held up to the height of 30°50 metres above zero of the Aswân gauge, the capacity of the proposed reservoir being 85 milliard cubic feet. These drawings were in accordance with accepted principles, and provided such a factor of safety as to ensure security. The commission which selected Aswân as the site for the Dam approved both the height of the Dam and the capacity of the reservoir, but it was afterwards settled that the former should only be carried to the height of 22'50 metres above zero of the Aswân gauge, with a corresponding reduction in the capacity of the reservoir to 35 milliard cubic feet. There were three members in the Commission, viz., M. Boulé, who was concerned chiefly about the Philæ temples, Signor Torricelli, an authority on pressures of masonry, and Sir Benjamin Baker, who had to decide all points connected with strains arising from expansion and contraction. Finally it was decided that the theoretical toe pressures should be limited to about 4} tons io the square foot. Comparison with existing dams shows that, as finally proportioned, the Aswân Dam was designed on extremely safe lines. In fact, though it was intended to hold up merely 35 milliard cubic feet, it was of such
proportions that engineers were justified in believing the work to be capable of impounding 70 milliards by raising the superstructure six metres above the original height. Prof. Pearson thinks that the “pressure of water behind a dam tends to cause failure by vertical fracture near the outer toe, instead of causing failure along a horizontal plane." Other experts, equally qualified to speak with authority, doubt the applicability of the new theory to the Aswan Dam. The erosion of the river bed has been satisfactorily dealt with, for the holes, many of them 20 feet deep, have been filled up, and on Sir Benjamin Baker's recommendation a protective masonry apron has been built from une bank of the Nile to the other. If necessary, a low weir will be built, similar to the auxiliary weirs built below the Delta Barrage by Sir Hanbury Brown. Nothing will be done about raising the Dam until the masonry apron has been finished. At the present time (July, 1906) "all the holes and depressions caused by the rush of water through the sluices have been filled up with solid granite masonry, set in cement-mortar, up to the level of the sills of the sluices, whence it is carried down in an easy gradient to meet the natural rock surface some 60 metres downstream of the Dam." The rumours which state that the Dam is unstable are “absolutely devoid of the smallest foundation. I should add that the number of persons who are in any degree qualified to express an opinion of any value on this question is extremely limited. To the best of my beliet, amongst those persons no single individual can be found who does not entertain entire confidence in the stability of the Dam” (Lord Cromer, Egypt, No. 1 (1906), p. 48).
The Asyût Dam is what is called an open Barrage, and consists of nu bays or openings, each 16 feet 5 ins. wide, and each bay is provided with regulating gates. The total length of the work is 2,691 feet, and a lock has been built on the west bank, large enough to pass the largest tourist boat plying on the river. Both works were begun by Messrs. Aird in 1898.
The ancient Egyptians called the Nile Hāp, or Hāpi 8
and the Arabs call it “Bahr,” which is applied to any large mass of natural water, whether sea, lake, or river. As the Egyptians divided their country into north and south, even so they conceived the existence of two Niles, which they called “Hāp Reset” 8 adanya the “South Nile,”and “Hāp Mehet” 8 - po slehet 8 o n the the “ North Nile.” Both Niles were represented by men having female attributes, and bearing upon their heads the plant which was characteristic of the region through which that Nile flowed ; thus y, the papyrus plant, represented the country of the south where the papyrus grew, and r, the lotus plant, typified the country of the The Source of the Nile at Philæ.
(From Rosellini.) north, i.e., the Delta, where the lotus grew. The god of one Nile was coloured red and the god of the other a greenish-blue; it has been thought