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THE NILE IN 1904
THE NILE IN 1904
BY Sir WILLIAM WILLCOCKS, K.C.M.G., F.R.G.S. LONDON E. & F. N. SPON Limited , 57 Haymarket . NEW YORK SPON & CHAMBERLAIN, 123 Liberty Street . Price 9 s/- net. Printed at the National Printing Department of Egypt, Cairo 1904. 1904. Dedicated to my old Chief and Master in Irrigation, Sir Colin Scott-Moncrieff, K.C.S.I., K.C.M.G., under whom I had the privilege of working for 20 years in India and Egypt....
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PREFACE
PREFACE
The publication of Sir William Garstin’s monumental work on the “Basin of the Upper Nile” is an event of such importance in the history of the Nile that the occasion should not be lost of bringing Lombardini’s work on the Nile to date. The information utilised by me in this book as far as the Upper Nile is concerned is obtained from Sir William’s Report; for the Blue Nile and Atbara I am indebted to M. Dupuis’ interesting appendix at the end of Sir William’s Report; and for the river north of Kh
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1. Introduction.
1. Introduction.
—In the introduction to his brilliant essay on the Hydrology of the Nile [1] , an essay, which, though written in 1865, foreshadowed much of what we know to day, Lombardini remarked, with much truth that, no river in the world lends itself to hydrological studies on so majestic a scale as the Nile. The most interesting river of the ancient world, it is still the most interesting river of our time; and, in spite of all that ancient and modern discoveries have unfolded, its discharges are to-day m
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2. Nomenclature.
2. Nomenclature.
—The nomenclature of the tributaries of the Nile is difficult to follow. In this book I shall call the river the Victoria Nile from Lake Victoria to Lake Albert; the Albert Nile from Lake Albert to the Sobat mouth (this reach is known generally as the Bahr el Gebel); the White Nile from the Sobat mouth to Khartoum; and the Nile from Khartoum to the sea. The Blue Nile stretches from Lake Tsana in Abyssinia to Khartoum....
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3. Description of the course of the Nile.
3. Description of the course of the Nile.
— Chapters II and III contain detailed descriptions of the Nile and its main tributaries, and this paragraph is a short epitome of what is written there about the course of the Nile. The Nile drains nearly the whole of north-eastern Africa, an area comprising 3 million square kilometres. Its main tributary, the White Nile, has its furthest sources in south latitude 4°, near Lake Tanganyika. Known as the Kagera, it is one of the feeders of Lake Victoria, and has a course of 600 kilometres before
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4. The Slopes and velocities of the Nile in its different reaches.
4. The Slopes and velocities of the Nile in its different reaches.
— Table 2 of Appendix B and Plate II comprise all the information available under this head which I have been able to collect. For the slopes I have adopted the following data: From Khartoum to Wady Halfa I have adopted the generally accepted levels of the original Soudan railway survey. From Wady Halfa to the sea I have levelled myself. Upstream and downstream from the adopted levels I have carried the levels by the aid of slopes calculated from velocity and hydraulic mean depth data. It seems
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5. Catchment basins of the Nile and its tributaries.
5. Catchment basins of the Nile and its tributaries.
— Table I , of Appendix A gives the areas of the catchment basins of the Nile. The total area according to the table is 3,007,000 square kilometres. The limits of the basin are depicted on Plate I , and, with rare exceptions, they are now fairly well known everywhere. North of the 20th parallel of latitude the watershed on the west of the Nile is not far removed from the edge of the plateau skirting the Nile valley. The plateau falls away to the west, and occasional ravines find their way to the
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6. The climate of the Nile valley.
6. The climate of the Nile valley.
—This paragraph would have been much more complete if Capt. Lyons’ monograph on the Meteorology of the Nile valley had been published. In considering the climate I shall follow the subdivisions of the catchment basin of the Nile contained in Table I . In the catchment basins of Lakes Victoria and Albert, the mean annual rainfall may be taken as 1.25 metres, with great fluctuations between good and bad years. Neglecting here and through this paragraph, the light occasional falls of rain which are
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7. The Geology of the Nile Valley.
7. The Geology of the Nile Valley.
—South of Gondokoro along the Victoria and Albert Niles, and at the lakes, the rocks are generally granites, crystalline schists and quartzites. The hills of Uganda are covered with red clay and marl on the higher lands, while the valleys consist of a rich black loam. All the cataracts are granites and granitic rocks or diorites. The Ruenzori range consists of lofty volcanoes. The surface of the ground is covered with a fine Kankar (nodulated limestone) in many places. North of Gondokoro the pla
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8. The discharges of the Nile and its tributaries.
8. The discharges of the Nile and its tributaries.
—Reference should be made to tables 24 and 25 which embody the results of an exhaustive examination of the observed discharges, the cross sections, the gauges of the Nile Valley, and the calculated discharge tables made for these gauges. Many of these tables are founded on only two or three discharges and some on only one, but they have been prepared with the greatest care and referred to all the existing gauge observations, and are good working tables, which can be modified and improved as time
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9. Lake Victoria Nyanza.
9. Lake Victoria Nyanza.
—Lake Victoria, the true source of the Nile, lies on the Equator, and fed by abundant rains and numerous streams, discharges its surplus waters over the Ripon Falls, and gives birth to the Victoria Nile. Its most important feeder, the Kagera, whose southernmost tributary rises in the Kangosi hills 2000 metres above sea level in south latitude 4°, has a length of some 600 kilometres. The direct line across the lake from the mouth of the Kagera to the Ripon Falls is 220 kilometres, so that in acad
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10. The Victoria Nile.
10. The Victoria Nile.
—From the Ripon Falls to Lake Albert, the Victoria Nile has a length of 400 kilometres. The first 64 kilometres are down a steep slope, in a stream varying from 300 to 500 metres in width. Any project for a regulator at the Ripon Falls should contemplate development of electricity for working a railway along these 64 kilometres. The next 237 kilometres are through a flat marshy land, partly lake, partly swamps, but with the water never more than 4 to 6 metres deep. In this reach the Nile is navi
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11. The Semliki River.
11. The Semliki River.
—The Semliki river has its sources in Lake Edward just south of the Equator and flows into the southern end of Lake Albert, just as the Victoria Nile flows into the northern end. Lake Edward with the addition of Lake Dueru has an area of some 2500 square kilometres and lies about 965 metres above sea level. Its waters as described by Sir William Garstin, are green in colour and brackish. The Semliki river discharges the surplus waters of the lake, and may be considered as having a discharge of 1
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12. Lake Albert Nyanza.
12. Lake Albert Nyanza.
—Lake Albert has an area of 4500 square kilometres and lies about 680 metres above sea level. We have left the high lands of Uganda and are in the stifling heat of tropical Africa. There are considerable deposits of salt along the east shore of Lake Albert, as there are also around Lake Edward. According to Sir William Garstin, the waters of Lake Albert are brackish near the shores, but perfectly sweet and clear in the middle of the lake. It is due to the waters of Lake Victoria that those of La
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13. The Albert Nile.
13. The Albert Nile.
—The Albert Nile, or the Bahr-el-Gebel, has a length of 1280 kilometres from Lake Albert to the mouth of the Sobat river. For 218 kilometres, past Wadelai to Dufile, it has a broad stream with a sluggish current as a rule, and covered with islands and papyrus marshes. This reach of the Nile is navigable. The fall here must be very little, and it may be considered as 8 metres. In high floods enormous quantities of pistea weeds float down this reach of the Nile. Papyrus and ambatch are very common
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14. The Gazelle River.
14. The Gazelle River.
—The Gazelle river, which flows into Lake No, has a catchment basin of 240,000 square kilometres, with an annual rainfall of 75 millimetres; and an additional catchment basin of 230 square kilometres with an annual rainfall of 30 millimetres; and yet the river discharges nothing in summer and about 40 cubic metres per second in flood. It is the most extraordinary river in the world, often blocked by sudd and invisible. It has practically no banks in flood or in times of low supply, while the wat
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15. The Bahr Zeraf.
15. The Bahr Zeraf.
—The Bahr Zeraf is the right hand branch of the Albert Nile which leaves the latter river north of Ghaba Shambe and joins it again midway between Lake No and the Sobat river. It is fed largely by the escape water of the Atem river brought down in a traceable channel and in flood by torrents from the hilly region east of Gondokoro. Beginning with a series of marshes and swamps, it gradually establishes its right to be called a river and finally after a tortuous and meandering course of about 270
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16. The Sobat River.
16. The Sobat River.
—This river drains 156,000 square kilometres lying between the catchment basins of Lake Rudolf and the Blue Nile. The rainfall in the mountainous region of Gallaland is plentiful and especially heavy in autumn, and were it not for the extensive lakes and marshes in its middle course, it would be a torrent in flood. Regulated and restrained by the lakes and marshes, this river has an extraordinarily even rise and fall, as a reference to Table 24 will certify. It is unfortunate that the Nasser gau
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17. The Sudd region.
17. The Sudd region.
—The Sudd region of the Albert Nile lies north of Ghaba Shambe and corresponds to that part of the river where not only do the floods overflow the banks, but the summer supplies can do so in many places. It is the delta of the river in a very embryonic stage. There are two main branches to the river, the Albert Nile proper and the Zeraf, which have both been already described. Both these rivers are liable to be blocked by sudd or blocks of living vegetation. These blocks are sometimes as much as
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18. The White Nile.
18. The White Nile.
—The White Nile stretches from the Sobat mouth to Khartoum and has a length of 838 kilometres and very little fall. It everywhere bears traces of having been the channel of the Blue Nile when in ancient times the Gebel-Royan hill had not been cut through by the Nile, and the Blue Nile itself flowed south into the great lake which is to-day the sudd region of the Albert Nile. If the Blue Nile discharged, as it does to-day, about 2500 cubic metres per second throughout the year, the Sobat 600 cubi
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19. The Blue Nile.
19. The Blue Nile.
—Compared to any river we have yet described, the Blue Nile is a true mountain stream. Draining the southern and more rainy half of Abyssinia, it is the principal source of the Nile in flood. Whatever waters it receives, it carries to the Nile and it is the true parent of the land of Egypt, for the deposit from its muddy waters is that Nile mud which has made Egypt. The Atbara carries waters which are probably more muddy than those of the Blue Nile, but compared to the Blue Nile the Atbara is a
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20. The Atbara.
20. The Atbara.
—The Atbara river flows into the Nile at El-Damer, south of Berber. It is essentially a torrent fed by the rains of north-eastern Abyssinia. The rains here begin early and end early, so that the Atbara is in high flood in August and falls quickly through September. Its floods last from June to October and the river is dry for the remaining months of the year. By dry it is meant that there is no running water, for the bed of the river contains numerous pools of water, which are nearly always deep
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21. The Nile from Khartoum to Assuân.
21. The Nile from Khartoum to Assuân.
—The Nile begins its course without any gauge to record its varying height. A gauge north of Omdurman, another upstream of the 6th cataract and a third downstream of the cataract are badly needed. Until these three gauges are erected and recorded, and another erected and recorded on the Blue Nile at Kamlin, about 100 kilometres above Khartoum, the behaviour of the Nile and its tributaries at their junction will never be exactly understood. Making use of the information which is obtainable, we ma
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22. The Nile from Assuân to the Barrage.
22. The Nile from Assuân to the Barrage.
—From Assuân to the Barrage, the length of the river is 973 kilometres in summer and 923 in flood. The slope in summer is 1 ⁄ 13000 and in flood 1 ⁄ 12200 The mean fall of the valley is 1 ⁄ 10800 . The slopes vary in the different mean reaches, the least being 1 ⁄ 14800 in the Kena Mudiria and the greatest 1 ⁄ 11400 in Beni Suef. In a high flood with a rise of 9 metres at Assuân, the rise in Kena will be 9.5 metres and only 8.2 in Beni Suef. Table 42 gives the mean areas of cross sections of the
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23. The Rosetta and Damietta Branches.
23. The Rosetta and Damietta Branches.
— Plates XVII and XVIII give longitudinal sections of the two branches of the Nile and their cross sections are given on Plate XI . During winter, summer, and low floods, regulation at the Barrage interferes with the natural discharges of the two branches. The Damietta branch is gradually silting up and decreasing in size, while the Rosetta branch scours in high floods. The mean width of the Rosetta branch is 500 metres, and the mean area of the section in flood is 4000 square metres. The mean w
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24. The Nile in flood.
24. The Nile in flood.
—We are now in a position to apply our knowledge of the Nile and its tributaries to an examination of the behaviour of the rivers in flood and in time of low supply. Lake Victoria, the Victoria Nile, and Lake Albert may all be considered as the great equatorial regulators of the Nile. The river, as a river, begins at the outlet of Lake Albert, i.e., at the head of the Albert Nile. Generally at its lowest in April, it rises gradually and reaches its maximum in November. The mean minimum of 600 cu
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25. The Nile in low supply.
25. The Nile in low supply.
—We have so far considered the Nile in flood, it now remains to quickly dispose of the low supply. After reaching its maximum, the Atbara, which is a torrential river, falls more rapidly than others, and by the end of September has practically disappeared; after the middle of September the Blue Nile falls quickly, while the White Nile with its large basin, gentle flow and numerous reservoirs, falls very deliberately. The mean minimum discharge of the White Nile at Gondokoro in an ordinary year,
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26. Nile water.
26. Nile water.
—For the following information I am principally indebted to M. J. Barois’ “Les irrigations en Egypte” just published, and to an article by Mr G. P. Foaden in the Journal of the Khedivial Agricultural Society for January 1903. The colour of Nile water is generally a pale yellow, but in June, when the first indications of the coming flood are given by a continuous gentle rise of the river from its minimum gauge, the water changes to green and remains so for two or three weeks. This green water has
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27. The soil of the Nile valley.
27. The soil of the Nile valley.
—According to numerous analyses made of Egyptian soil in 1872 by MM. Payen, Champion and Gastinel, the soil of Egypt consists of Some stiff soils contain 84 per cent argile and some light soils contain 68 per cent sand. As one approaches the Mediterranean the quantity of chloride of soda increases and runs from a fraction to 4, 5, and even 10 per cent. From the means of ten samples of soil from Kena Mudirieh analysed for me in May by Mr. Frank Hughes of the Agricultural Society we gather that th
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28. Basin irrigation.
28. Basin irrigation.
—Considering the times of flood and low supply, the climate of Egypt, the turbidity of the Nile flood, and the deltaic formation of the Nile valley, no better system than basin irrigation as practiced in Egypt could possibly have been devised. If the flood had come in April and May and been followed by a burning summer, or if the actual autumn floods had been followed by the frozen winters of Europe or the warm winters of the Sudan, basin irrigation would have been a failure or a very moderate s
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29. Perennial Irrigation.
29. Perennial Irrigation.
—The foundation-stone of the conversion of the whole of Egypt from basin to perennial irrigation was laid by Mehemet Ali in 1833, when he began the construction of the Barrages across the Nile branches north of Cairo. These weirs were intended to raise the summer level of the Nile by 3 metres. As the ordinary summer level of the Nile was 1.50 metres above its bed, the weirs were expected to raise it 4.50 metres above the Nile bed. The old basin canals had to be considerably deepened to take in t
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30. Flood protection in Egypt.
30. Flood protection in Egypt.
—The Nile during high floods is considerably above the level of the country, which is protected by embankments stretching from Assouân to the sea. In Upper Egypt, a very high flood is one metre above the country; in Middle Egypt it is 2 metres, and the same on the Rosetta branch of the Nile. On the Damietta branch it is 3·50 metres in places. In parts of Upper Egypt, but nearly everywhere in Lower Egypt, the Nile on curves is protected by stone spurs. These spurs contain each from 4,000 to 250 c
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31. Projects.
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 b
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32. The raising of the Assuân dam.
32. The raising of the Assuân dam.
—Egypt already possesses the germ of all the storage works she needs. Six years ago a few far-seeing men saw clearly what all of us understand to-day; but among the few, no man had greater faith in the future of the country than Sir Ernest Cassel. The Assouân Reservoir project had been lying buried for four years in official pigeon holes, when in 1898 Sir Ernest came forward with the funds, and with Sir John Aird & Co., as contractors, and Sir Benjamin Baker as Consulting Engineer, under
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33. The Wady Rayan Reservoir Project.
33. The Wady Rayan Reservoir Project.
—When the Assouân dam will have been raised, we shall be standing on the threshold of what it will be able to do. The projected Wady Rayan reservoir, or the modern Lake Mœris, will be well able to supply the two remaining milliards of cubic metres of water when working in conjunction with the Assuân Reservoir. The great weakness of this projected lake has lain in the fact that by itself it could give a plentiful discharge in April and May, less in June, and very little in July, and it was for th
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34. Lake Albert reservoir project and project for training the Albert Nile and the Zeraf River.
34. Lake Albert reservoir project and project for training the Albert Nile and the Zeraf River.
—If we wish not only to irrigate the whole of Egypt, but to include the Sudan in the sphere of operations we must regulate the supply issuing from Lake Albert Nyanza and ensure its passage through the great swamp regions. To my mind no work in the Sudd regions will be of any substantial value unless the Albert reservoir dam is first built. Tabulating the information collected in the gauges and discharge tables we may state that the discharge of the Albert Nile in cubic metres per second between
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35. Flood protection for Egypt.
35. Flood protection for Egypt.
—In paragraph 30 it was stated that the floods in the Delta or in Lower Egypt can rise to a height of from 2 to 3 1 ⁄ 2 metres above the level of the country. Such floods are really dangerous and means should be found for moderating them. The Wady Rayan reservoir, when converted into the modern Lake Mœris and acting as a reservoir, will have one great advantage, it will be able to lower a high flood 30 centimetres for 50 days. This will give relief to the Nile, a relief which will be much apprec
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36. Complete project for water storage and flood protection for Egypt.
36. Complete project for water storage and flood protection for Egypt.
—The complete project for water storage and flood protection for Egypt as proposed by me, contemplates the following works:— To these have to be added the approximate estimates of the proposed works on the Upper Nile:— The total expenditure amounts to £6,000,000 spread over 12 years. The great advantage of undertaking all those works together may be thus summarized. The increased supply from the Assuân reservoir will be felt in Egypt after a period of two years. Five years later the waters of th
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37. Sir William Garstin’s programme for water storage and flood control.
37. Sir William Garstin’s programme for water storage and flood control.
—In the first appendix to his Report on the Upper Nile, Sir William Garstin, G.C.M.G., Adviser to the Ministry of Public Works, has drawn up a programme of works for water storage and flood control in the Nile valley. He approves of the raising of the Assuân dam for £500,000, and the conversion of the Rosetta branch of the Nile into a flood escape for £900,000. He then conditionally approves of a proposal suggested by Mr. J. S. Beresford, C.I.E., for making a straight cut from Bor on the Albert
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38. Project for converting the basin irrigated lands of Upper Egypt into perennially irrigated lands.
38. Project for converting the basin irrigated lands of Upper Egypt into perennially irrigated lands.
—No consideration of this question would be complete without first examining into the changes which would be made in the regimen of the Nile flood by the contemplated conversion of basin irrigation into perennial irrigation. This question was examined very thoroughly by me in 1892 and 1893 and I give here my arguments for not anticipating any serious difficulties. We have to consider the effect of the introduction of perennial irrigation on the regime of the Nile. The perfection of the perennial
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39. Development of the Sudan.
39. Development of the Sudan.
—Lord Cromer’s wise decision to construct the Suakin-Khartoum railway immediately and the Abu Hamed-Dongola railway as soon as possible, is the charter of the development of the Sudan. With these railways and especially the former in working order, we can arrange for irrigation works for the production of cotton and wheat for export, knowing that they can be exported at a cost of transport which will not be absolutely prohibitive. The soil of the Sudan along the Blue Nile, the Atbara, the Main N
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40. The Oases.
40. The Oases.
—The chief oases [6] of the Libyan desert—Dakhla, Kharga, Baharia and Farafra,—occupy extensive depressions cut down through the horizontal Eocene strata [7] to the underlying saddle of Cretaceous rocks; some of the more porous beds of the latter are water-bearing and from them, either through natural passages or through artificial borings, the water rises to the surface, often under considerable pressure. The floor level varies considerably but the cultivated lands in general lie between 70 and
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41. Dakhla oasis.
41. Dakhla oasis.
—This, by far the most important and prosperous of the Egyptian oases, lies three days’ march west of Kharga, or about 300 kilometres due west of Armant in the Nile valley. The site is a depression lying at the foot of the great east and west Cretaceous escarpment, bounded to the south by the undulating desert of Nubian sandstone, which stretches unchanged almost to the heart of the continent. The inhabitants of Dakhla, numbering over 17,000, are distributed among 12 villages and form a practica
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42. Kharga oasis.
42. Kharga oasis.
—Kharga, the easternmost of the two southern oases, is a north and south lying depression, mostly bounded by steep and lofty escarpments but open to the south and south-west. A great part of its floor, which is composed of the Nubian sandstone, is buried under sand accumulations. There are seven principal villages, besides numerous hamlets and smaller settlements, with a total population of under 8,000. Taxes are levied as in Dakhla and amount to slightly over £E. 1000. The adult palm trees in t
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43. Baharia oasis
43. Baharia oasis
, lying 180 kilometres west of Minia, is a large natural excavation 150 metres deep and entirely surrounded by escarpments. The cultivated lands bear a very small proportion to the total oasis-area; their general level is 110-115 metres above sea level, rising to 155 metres at Ain-el-Haiss in the southern part of the depression. There are four chief villages with a population, inclusive of outlying settlements, of just over 6,000. The standard of public health in this oasis is low, mainly owing
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44. Farafra oasis
44. Farafra oasis
occupies a large semicircular depression 300 kilometres west of Assiut. The floor is formed of the white chalk at the top of the Cretaceous, but at Ain-el-Wadi, a spring in the north part of the depression at 26 metres above sea level, the underlying beds are locally exposed. The solitary village of Qasr Farafra is situated on the western side at 76 metres above sea level, and contained 542 inhabitants at the last census. In the entire area there are some 20 springs, mostly grouped round the vi
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45. The Geology of Egypt
45. The Geology of Egypt
[8] . The north-east corner of Africa, lying between the Red Sea on the east and the sand merged portion of the Libyan Desert on the west, and stretching from the Mediterranean to the 22nd parallel of north latitude, both in its topographical and geological characters is distinctly tripartite, as follows:— (1) A rugged broken undulating sandstone desert, forming the southern part of the country; (2) Elevated plateaux, for the most part of limestone, stretching from lat. 25° N. (approximately) to
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46. Igneous rocks.
46. Igneous rocks.
The most ancient rocks in Egypt are found in the central igneous ranges of the Red Sea Hills and in the crystalline floor underlying the sandstones in the southern part of the country. In Nubia the crystalline rocks consist largely of granite and gneiss, with associated diorites and schists, traversed by basaltic and felsitic dykes. Cataracts have been formed at those points where the river crosses the hard igneous belts, which may be regarded as the summits of the higher ridges of an old erode
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47. Sedimentary rocks.
47. Sedimentary rocks.
Geologically the sedimentary deposits of Egypt are not of great age. Broadly they consist of a great development of Upper Cretaceous and Eocene strata, followed by more restricted deposits of Oligocene and Miocene age, the still younger formations being represented only by comparatively local though important, accumulations. As a general rule the different members of the Cretaceous and Tertiary succeed each other in regular order from south to north, the strata being undisturbed and dipping nor
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48. Upper Cretaceous.
48. Upper Cretaceous.
The Cretaceous system in Egypt is divisible into three main groups, (1) a great thickness of freshwater arenaceous sediments known as the Nubian Sandstone, of Senonian age in the south (Dakhla, Nile valley, and southern part of Eastern Desert), and Cenomanian age in the north (Baharia, Abu Roash(?), and Wadi Araba); (2) 300 metres of argillaceous deposits with bone-beds near the base, of Senonian age; (3) a deep water foraminiferal white chalk (Danian) 60 to 100 metres thick, especially develop
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49. Eocene.
49. Eocene.
Our knowledge of the junction of the Cretaceous and Eocene in several parts of the country leaves much to be desired. Where the Eocene is most fully developed its basal member consists of a group of green argillaceous deposits, known as the Esna shales, well seen at the base of the cliffs throughout the Esna-Qena reach of the valley. These beds everywhere pass conformably upwards into the Lower Eocene (Libyan) limestones above, but in the Nile Valley and the Eastern Desert the exact line of dem
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50. Oligocene and Miocene.
50. Oligocene and Miocene.
Throughout Oligocene and Miocene times conditions similar to those which led to the deposition of the Upper Eocene formation in the Fayûm prevailed, accompanied by a continual retreat of the sea to the north. In the littoral area marine beds were intermingled with the sediments brought down by rivers from the land to the south; and throughout these deposits the remains of land animals and great quantities of large silicified trees are common. A considerable part of the deserts east and west of
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51. Pliocene, Pleistocene and Recent.
51. Pliocene, Pleistocene and Recent.
In Pliocene times the relative areas of land and sea approximated to those of to-day and powerful earth-movements initiated the formation of the lower part of the Nile Valley. The determining faults and the huge blocks of displaced rock are visible along the cliff walls in many parts of the valley, and at Gebelain isolated ridges of highly tilted limestone protrude above the floor of the trough, though as a rule, except near the cliffs, the faulted rocks are invisible, being buried under great
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52. Economic products.
52. Economic products.
Limestones for building and other purposes are abundant in the Lower and Middle Eocene formations, though as a rule of only medium quality. The chief quarries are those of Jebel Mokattam, Tura, Heluan, Abu Foda, Harîdi, and el-Tarif. At Isawia, near Tahta, a fine tough freshwater tufaceous limestone of Pleistocene age occurs, and was largely used in the construction of the Assiut barrage. Clays of good quality are not widely extended, though certain bands of the Esna shales are very largely use
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Appendix F.
Appendix F.
1903 [9] 641 + 52 for side channel. [10] 1847 + 138 for side channel....
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Appendix G. TABLES GIVING MEAN MONTHLY DISCHARGES OF THE NILE AND ITS TRIBUTARIES DURING 1902, 1903 AND 1904.
Appendix G. TABLES GIVING MEAN MONTHLY DISCHARGES OF THE NILE AND ITS TRIBUTARIES DURING 1902, 1903 AND 1904.
[11] Blue Nile water flowing up the White Nile and decreasing the normal discharge....
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Appendix I.
Appendix I.
Note. —The very high discharges at Assuân and Cairo in April and May 1879; the minimum discharge of that year was about 1500 cubic metres per second. There has never been any discharge like that since....
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Appendix J. DISCHARGE TABLES OF THE DIFFERENT GAUGES OF THE NILE AND ITS TRIBUTAIRIES.
Appendix J. DISCHARGE TABLES OF THE DIFFERENT GAUGES OF THE NILE AND ITS TRIBUTAIRIES.
This gauge is in backwater when the north end of the Sudd region is flooded. This table is only very approximative. (1) These discharges include the Rahad river. They represent the discharges below the Rahad river junction referred to the Wad Medani gauge. (2) During a high flood the river scours, and it silts during a low flood; consequently for exact discharges below 5 metres, the section of the river should be taken annually in December. This gauge is in backwater when the White Nile is disch
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Appendix K. TABLES GIVING DETAILED INFORMATION ABOUT THE NILE BETWEEN ASSUÂN AND CAIRO.
Appendix K. TABLES GIVING DETAILED INFORMATION ABOUT THE NILE BETWEEN ASSUÂN AND CAIRO.
Zero is R. L. 85·00 metres or mean low water level....
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