31. Projects.
—No account of the Nile in 1904 would be complete without an enumeration and slight examination of the projects before the public for the provision of sufficient water to the Nile in times of low supply to insure the perennial irrigation of the whole of Egypt; to utilise these perennial waters by converting basin tracts into perennially irrigated ones; to protect the country from the dangers accompanying high floods; and to permit of the reclamation of the low salted lands of Lower Egypt which border the Mediterranean sea.
Egypt has a total irrigable area of 61⁄4 millions acres. Of this area, 1⁄4 of a million acres, which are to-day inundated in flood and lie along the edge of the deserts, must continue to be inundated in flood for all time, to prevent the sands of the desert from spreading over the Nile Valley. Their value is £5,000,000. Four million acres are perennially irrigated. They have a mean value of £55 per acre, and have a total value of £220,000,000. Of the remaining two million acres, two-thirds are irrigated only in flood and one-third is not irrigated at all. These 2 million acres have a mean value of £25 per acre, and are worth £50,000,000. The land of Egypt may be considered as worth £275,000,000 to-day. If it were possible to perennially irrigate the 2 million acres which are without such irrigation, their value would be increased by £30 per acre, or by £60,000,000.
The problem before us is how to provide perennial irrigation to these 2 million acres and so add £60,000,000 to the wealth of the country.
It has been calculated that each milliard of cubic metres of water stored in reservoirs situated in Egypt itself is sufficient to insure the conversion of half a million acres from flood to perennial irrigation. Egypt therefore requires reservoirs capable of storing 4 milliards of cubic metres of water.
In Mehemet Ali’s time, the great preoccupation of the Government was the pressing on of the cultivation of cotton, and as this crop needed perennial irrigation, the securing of an abundant supply of water all the year round was the problem of the day.
The fame of the ancient Lake Mœris had made a profound impression on the mind of Mehemet Ali, and he urged on his chief engineer the necessity of undertaking similar works. Linant Pasha first set himself to discover the site of the ancient lake, and then estimated roughly the cost of reconstructing it, but considered the cost prohibitive. He recommended Silsila as a suitable site for a weir and a canal head. The failure of the Barrage discouraged the Government from undertaking new works and the question dropped. In 1880 Count de la Motte proposed a dam at Silsila and a reservoir to the south of it. He also proposed putting a capacious depression to the east of Kalabsha in communication with the Nile by the aid of a dam at Kalabsha.
About two years later Mr. Cope Whitehouse suggested utilising the Wadi Rayan depression as a reservoir. This depression had been already mentioned by Linant Pasha in his book and located by him on his hydrological map. Financial difficulties prevented Sir Colin Scott-Moncrieff from immediately considering the question of reservoirs. The success of the Barrage repairs in 1887 however gave new life to the question of reservoirs and Sir Colin Scott-Moncrieff deputed Col. Western to give scope to the suggestion made by Mr. Cope Whitehouse, to make plans of the Wady Rayan and the deserts between it and the Nile, to find out the capacity of the reservoir, and see if it could be utilised. Col. Western’s report, plans and estimates were printed by the Egyptian Government in 1888. At the same time I was deputed to examine the other projects of Count de la Motte. In 1889 and 1891 I reported unfavourably on them, because I could find no depression near Kalabsha to put in communication with the Nile, and could find no rock at Silsila on which to build a dam. The Bergat Takham pan was the only depression near Kalabsha which could have been used as a reservoir and it was over 100 metres above the level of the Nile flood; while both in the Silsila pass and the Silsila gate I bored for rock and was everywhere still in sand 10 metres below the level at which the existence of rock was assumed by the Count’s engineers. On my report reaching Cairo, M. Prompt proposed using the trough of the Nile itself at Kalabsha as a reservoir in place of the depression which did not exist. Col. Western left the country in 1890 and I became Director General of Reservoir Studies. M. Prompt had supposed that rock could be met with at Kalabsha at a depth of 4 metres below low-water level. I could not find it at a depth of 26 metres. After sounding and boring at every possible site on the Nile and surveying, boring, and levelling in the desert between Wadi Halfa and the Fayoum, I submitted my report in 1894, proposing an open dam at Assouan of a type which I trusted would meet the requirements of a Nile reservoir dam. Sir William Garstin approved of the site and the design, and the dam was built between 1898 and 1902 with Mr. Maurice Fitzmaurice C.M.G, as resident engineer.
The Assouan Reservoir at its present level contains one milliard of cubic metres of water which will suffice for the conversion of half a million acres to perennial irrigation, adding £15,000,000 to the wealth of the country. But though the dam was only completed at the end of 1902, already the whole of the water has been devoted to special tracts, and the Government is reluctantly compelled to refuse all applications for water.