NILE

although the geographical problems connected with the origin of the river have been solved, the nile continues to offer problems of extraordinary interest in connec- tion with the conservation and distribution of its waters. the . ais nilsson—nitrogen, fixation of energy formerly directed to exploration has only been diverted to a closer and more scientific study of the hydrography of the river, with a view to determining how the available flow of water in its various tributaries can be most advantageously and economically protected from dissipation and wastage in the swamps of the upper river, and stored in reservoirs for utilisation as required. these studies have mostly been directed by the egyptian govt. towards increasing the flow of the river in the early summer months, when its natural flow falls short of require- ments for irrigation in egypt; it has come to be realised that the control of the nile waters is not wholly an egyptian question but concerns the rapidly developing countries higher up the river. the aswan, gebel aulia and mukwar dams —the original aswan dam, which was opened in 1902, was raised in height by seven metres in 1912 and the storage capacity of the reservoir increased from 1,000 million cu. metres to 2,250 million cu. metres of water. following on sir william garstin’s famous report on the basin of the upper nile (british blue book, egypt, no. 2 1904), schemes for constructing a large reservoir on the lower white nile by means of a dam at gebel aulia some 20 m. south of khartum, and for a canal to irrigate the great gezira plain between the blue and white niles, began to take definite form about 1913. progress with these schemes was necessarily suspended during the world war, and in the mean- while the increasing tendency towards the development of an independent existence by the sudan caused all schemes for the control of the river beyond the limits of egypt proper to be viewed with some apprehension and mistrust in egypt. the general position was summed up to date by the then adviser to the egyptian ministry of public works, sir murdoch mac- donald, in nile control (published by the egyptian govt. in 1920), and an international commission was appointed by the egyptian govt. to report on the proposed works. the commission reported favourably on the general scheme out- lined in nile control, and pointed out that under a carefully con- sidered scheme of control there was sufficient water to meet any possible developments in both egypt and the sudan for many years to come. financial considerations, complicated by the political position, again led to the temporary suspension of the works and to the preparation of further reports on the irrigation programme by mr. c. e. dupuis, formerly adviser to the egyp- tian ministry of public works (published by the egyptian govt. in 1925). the construction of the gezira canal was then actively resumed by the sudan govt., and the canal, with its great dam and reservoir, with a capacity of nearly 500,000 million cu. metres of water, at makwar, near senaar, on the blue nile, was completed to the extent necessary for the irriga- tion of 300,000 ac. in 1925, and formally opened in 1926. the egyptian govt. also actively pressed on the construction of the gebel aulia dam and reservoir on the white nile, with a storage capacity of about 2,500 million cu. metres of water, and is taking up again the scheme for the canalisation of the river through the swamps, on which some preliminary work was done between 1904 and 1913. (sce dams; irrigation.) lake albert.—it is further recognised that to be fully effective this canalisation of the river must be supplemented by further storage works higher up the river, presumably by the conversion of lake albert into a reservoir, but this scheme has not yet emerged from the stage of preliminary consideration. the most recent information concerning the physical conditions and regime of the great lakes forming the basin of the upper white nile, essential to the consideration of this project, has been collected in a report on the lake plateau basin of the nile by mr. h. e. hurst (published by the egyptian govt. in 1925.) lake tsana.—the study of the possibilities of lake tsana as a reservoir for the blue nile, originally reported on by mr. c. e. dupuis in 1903, has been continued by expeditions visit- ing the lake under mr. a. b. buckley in 1916-7, and under mr. g. w. grabham in 1920-1. the results of all these studies have been published by the egyptian govt. and the report of the mission to lake tsana in rgz0-1 by messrs. g. w. 1079 grabham and r. p. black is particularly full and interesting. all reports agree in emphasising the extreme suitability of lake tsana for conversion into a reservoir of a capacity of between 3,000 and 4,000 million cu. metres. the political questions aris- ing from the gradual conversion of the nile from a natural river into an artificially regulated stream, whose flow is controlled by reservoirs at various points on its course in several different countries, are only just beginning to make themselves felt, and a comprehensive solution of the resulting difficulties has yet to be found.! navigation and water power.—from the point of view of navigation and trade no new developments have taken place on the nile in recent years. the river remains a most useful high- way for local traffic in the various sections into which its length of 4,000 m. is divided by the occurrence of falls and rapids; but the nature of these breaks is such that the development of through traffic on any scale is never likely to be economically possible. there are considerable possibilities for the develop- ment of water-power on the nile, especially at the ripon and murchison falls in uganda; and the utilisation of the large amount of power running to waste at the aswan dam has been repeatedly considered and discussed; but the localities in which these opportunities occur are remote, and no useful application of them to practical purposes has yet been devised; in the case of aswan the intermittent character of the power obtainable, which though very large when the reservoir is full in the early part of the year is practically nil during the flood season, has hitherto proved an insurmountable objection to economic utilisation. (cc bsd,):: nilsson, christine (1843-1021), swedish singer (see 19.701), died at copenhagen, denmark, nov. 22 1921.