CONTROL OF THE NILE

THE Control of the Nile waters has occupied mankind since the dawn of history. Water is the first and last consideration in a rainless land-it is the life of the people; and thus Egypt has witnessed a continuous struggle to utilise to the fullest possible extent the waters of the river whose valley and delta mark the limits of cultivable land. To the ancient Egyptians the sacred river presented the same problem as faces the modern engineer. How can the waters be best utilised during the flood months of late July, August, September, and October, and how may the sluggish river be harnessed to the needs of men during the season of low water?

Before the Emperor Nero had sent his expeditions to discover the sources of the mysterious river, and Juvenal had sung Divitis ostia Nili, the Pharaohs had introduced a system of irrigation which was hardly improved upon until the early years of the nineteenth century. From the banks of the Nile were cut deep channels, along which the water flowed during the season of the flood inland to the foothills. Parallel to the river, and forming a series of dykes, were built a number of embankments, which formed basins to retain the overflow. They retained the precious silt, brought down from the plateaux of Central Africa, spreading it over the land and rejuvenating the soil year by year in a far more efficient and thorough fashion than the modern agriculturist can do by artificial means. Each basin was connected with its neighbour performing the functions of a natural drain, and thus the saline qualities of the water were carried back to the river when the flood had played its part in enriching the soil. The peasant had the simple task of casting his seed to the winds, which carried it across the water-saturated soil. In the delta the process of flooding was simpler, owing to the ease with which water could be drawn from the many branches of the river; and in this area the land brought under cultivation was probably not less than that now utilised by a more efficient and modern system of irrigation. During the period of inundation the country was a vast lake, dotted with villages emerging from the banks and mounds upon which the inhabitants had constructed their mud-brick houses.

Clusters of date palms threw up their slender trunks topped by spreading leaves, while upon the land the silt of the waters slowly settled, reviving and giving heart to the soil.

For 7000 years the system of basin irrigation introduced by the Pharaoh Menes and his successors remained in use. Rome made Egypt the granary of the West, and from the banks of the Nile quantities of grain were shipped to feed the turbulent mobs of the imperial city. But succeeding centuries changed the course of the world's commerce, and when Mohammed Ali made himself master of Egypt, in 1811, he cast about for new means of extracting wealth from the soil. Cultivation had hitherto been a one-crop system, dependent upon the flood. To him must be given the credit of foreseeing the immense advantage to be gained from constant irrigation throughout the year, enabling crops such as cotton, sugar, and rice to be grown. The climate was eminently suitable for their cultivation, but they required constant and careful watering during the summer. To do this he introduced a perennial system of irrigation by constructing a number of deep canals, known as sefi, or summer canals, to carry off the water at low flood. Miles of these canals were dug throughout the delta, carrying water for long distances in deep cuttings, from which it was drawn by means of water-wheels turned by animals, or slung up in buckets attached to poles.

Hitherto the enormous quantities of water brought down during the flood had been more than ample for the needs of every cultivator. Indeed, it was not possible, nor was it desirable, to attempt to regulate the enormous mass of water and silt that invaded the countryside, as the crops cultivated were not sown till the receding flood had deposited some two to three feet of mud on the fallowland. Sugar and cotton required more scientific methods. It was possible to overflood the soil, and it therefore became necessary to regulate not only the quantity of water irrigating the land during the low-flood season, but to buoy up and to prevent the complete swamping of the countryside during the season of inundation. This change in the processes of Nature carried in its train disadvantages and difficulties, which could only be overcome by experience. The careful regulation of water, though it brought untold prosperity and wealth to the cultivator, robbed the land of its full measure of renovating Nile silt. The sluggish waters resting in deep canals dropped their silt upon the beds of the canals, which quickly became choked, impeding the passage of the water. Canals became blocked for miles, and narrow ponds were formed here and there down their length. This lack of silt had the effect of diminishing productivity, and great efforts were required annually to keep the waterways open. As an inevitable consequence the scramble for water resulted in the rich man

utilising every means in his power to obtain a supply, while the peasant often left his crops on the field to dry up under the fierce sun that caked his land into a hard, compact mass cut here and there by long fissures.

Added to these difficulties was the important question of drainage. It was not enough to provide the means for cultivation; drainage outlets must be cut to clear the sodden soil from the effects of water-logging. Saline deposits rise quickly, turning good land into marsh; and although drains were dug, the improvident fellah (or peasant) more often used them as in-takes than as outlets to cleanse his land. An inspector of irrigation can imagine no more heinous crime than this, yet it was a frequent occurrence; and it was a matter for wonderment to the fellah why a duplicate system of canals was required, unless they were both intended to carry to his fields the precious fluid.

Every peasant knew the state of the river, and the height of the flood, measured by the rock-cut gauge at Assuan, was flashed from end to end of Egypt as the river rose during the early weeks of the flood season. In recent times readings are taken at many localities, even as far south as Khartoum and beyond, so that the available water is known long before the maximum flood reaches the delta. The longest series of records are the readings of the Roda gauge at Cairo, which runs from A.D. 641 to 1451, and from 1737, with one break, up to the present time. The early readings cannot be regarded as strictly accurate, as upon them depended the taxation assessments on land; and there would seem to be no doubt that the Arab cultivator managed to obtain a registration of incorrect readings for the purpose of evading the tax collector. To the peasantry a low year brought in its train disaster. Well might the Arab poet describe the pics measured at Assuan as 'The Angels of Death' and the marble column in the well at Roda, upon which twenty-four measurements were cut by the Caliph AlMutawakhil, as The Column of Destiny.' A rise of eighteen divisions on the column was generally regarded as the height of the lowest inundation; twenty was excellent; but at twenty-four the overflooding was ruinous.

Mohammed Ali early realised the impossibility of maintaining a complicated irrigation system without assistance. He called in the help of French engineers; and to one of these, Mougel Bey, must be given the credit for evolving the Cairo Barrage. Mougel Bey declared that the only method by which water at low flood could be obtained was to dam the apex of the delta below Cairo. By holding up the waters and by adding four metres to the water level sufficient could be retained to supply the entire needs of the delta. The plan was immense in conception and in 1842 the work was commenced. Two bridges were constructed, one across the

Rosetta branch and the other across the Damietta branch, pierced by a number of sluices which were opened and closed by sliding screens. Behind the bridges upstream are the entrances of the summer canals. Thus when water is required the sluices are closed, buoying up the waters and forming an enormous barrier stretching across both branches of the river. Unfortunately, engineering science was not then in a position to tackle the problems unexpectedly met with, and though the barrage was in partial use in 1863 the frequent settlement of its foundations caused it to be abandoned, and in 1883 it was officially declared useless.

The barrage was the beginning of a series of works which were continued and planned by British engineers from 1883 onwards. Their achievements must rank as the greatest series of irrigation works in the world; and in controlling the waters of the Nile from Assuan northwards they have saved Egypt from reverting to an impecunious State of struggling peasantry. It is true that other engineers may have solved this problem in a like manner, but the happy circumstance of having the principal departments of State staffed by Englishmen under the guiding hand of Lord Cromer allowed their task to be completed in a more thorough and ambitious manner than could otherwise have been the case.

The task of the newly constituted Irrigation Department may, for the sake of convenience, be divided into two portions, though it should be realised that both series of works proceeded concurrently. In the first place, the almost complete breakdown of the summer canals necessitated a thorough revision of the whole question of perennial irrigation in the delta. As forming a section of this work of reconstruction, the reparation of the barrage was of first importance. Secondly, the system of basin irrigation which had existed for thousands of years in Upper Egypt called for its substitution by the perennial system, in order that the maximum amount of land might be brought under cultivation and the land already cultivated be provided with a constant supply of water to grow more valuable crops. Mohammed Ali and his successors had in general confined their schemes to the delta, but here and there powerful pumps had been installed, and some canals cut, which gave the benefits of regulated inundations to small areas in Upper Egypt.

The chiefs of the department were British engineers with big reputations, known popularly as 'The Wise Men of the East,' who entered on their task with an energy and enthusiasm that conquered the inertia and distrust of the natives and overcame the physical difficulties of these immense irrigation problems. Lord Cromer, writing in 1908, pays a tribute to their work:

The British engineer unconsciously accomplished a feat which, in the eyes of a politician, is perhaps even more remarkable than that of con

trolling the refractory waters of the Nile. He justified Western methods to Eastern minds. He inculcated, in a manner which arrested and captiIvated even the blurred intellect of the poor, ignorant Egyptian fellah, the lesson that the usurer and the retailer of adulterated drinks are not the sole products of European civilisation; and, inasmuch as he achieved this object, he deserves the gratitude not only of all intelligent Asiatics, but also of all Europeans-of the rulers of Algiers and of Tunis as well as those of India. (Modern Egypt, vol. ii., p. 465.)

Reorganisation in the delta proceeded over a number of years. The problem everywhere was to improve the existing system without interrupting its action, to increase the head of water while work on the canals was in progress, and to relieve the sodden soil by drainage where the water had been brought to it. New canals were dug and old canals repaired. Levels were corrected, regulators introduced, and a proper rotation for cultivators drawn up. Yet these improvements would have been useless had not the officials been empowered to insist upon the observance of regulations, and been able to bring pressure to break down the wall of prejudice that met them at every turn. It was no easy matter to train a population, accustomed for many years to divert at will the head of water from a canal, or to cut the banks or to lift water from the summer channels, to the detriment of their neighbours, into more provident methods.

The success of these reforms depended upon the barrage itself. The great work of reparation was commenced during the low water season of 1884. The temporary repairs effected during that year met with immediate success, to justify a more complete restoration. At each season of the low water portions of the dam were enclosed by blankets of earthen walls, from which the water was pumped until the bed of the river was revealed. The foundations, resting on sand and silt, were strengthened, the great containing walls thickened, and the structure reinforced against the subversive action of water. The sluices were supplied with mechanically worked iron gates, a set being fitted to the Damietta branch of the dam which had hitherto lacked this one essential attribute; and when the work was finished the barrage held an amount of water in excess of that contemplated in the original project. A small weir was afterwards constructed north of the barrage at Ziftah, on the Damietta branch. The effect of these works was at once evident. There was now a sufficient depth of water at the in-take to increase the flow by gravitation throughout the miles of summer canals. Less water was therefore wasted in transit, and the increased velocity carried the precious silt to the fields in place of distributing it along the beds of the canals. Finally it was found possible to increase the depth of the cuttings radiating northwards from the barrage, and thus to economise labour in the cleaning and maintenance of this network of waterways. As a