The enterprise was put through with great rapidity, the project fully realising the designs of its inaugurators.  By aid of this great structure, 2,500 square miles have been added to the area of the 10,500 miles hitherto subject to cultivation.  Its value to the country is at the least worth $100,000,000.  The dam extends for one and a quarter miles, and possesses 180 openings, each of which is twenty-three feet high, and will altogether allow the outpour of fifteen thousand tons of water per second.  Navigation up and down the Nile has not been impeded, since, by a chain of four locks, vessels are able to pass up and down the river.  Each lock is 260 feet long and thirty-two feet wide.  During flood-time the gates of the dam are open; while the flood is subsiding the gates are gradually closed, and thus, in a long season of low water, the reservoir is gradually filled up for use through a system of canals, whereby the waters can be drawn off for irrigation and the main flow of the Nile can be increased.  The lake thus formed is nearly three times the superficial area of Lake Geneva in Switzerland, and the waters are held back for a distance of 140 miles up the course of the river.  The reservoir is filled during the months of January and February, and from April to the end of August the water is let out for irrigation purposes from the bottom of the reservoir, thus enabling the sediment, which is of such value, to be carried out through the sluices.  Four or five waterings are allowed to percolate from it to the various regions which are thus brought under cultivation, and besides this the main supply of the river itself is artificially increased at the same time.

The dam has been constructed of granite ashlar taken from quarries near Aswan.  These quarries are the very same from which the ancient obelisks were hewn.  The amount of rock used was about one million tons in weight.  In building the dam it was found to be very difficult to lay the foundation, since the bottom of the river proved to be unsound, although in the preliminary reports it had been declared to be of solid granite.  In some instances it was found necessary to dig down for forty feet, in order to lay a perfectly secure foundation on which the heavy wall could be superimposed.  This required much additional labour, and great risk and damage was encountered during the progress of the work at the date of the impending rise of the waters of the Nile.  Rubble dams were raised to ward off the waters from the point where it was necessary to excavate.  The holes were gradually filled with solid blocks of granite; then the base of the structure, one hundred feet in width, was laid, and the massive piers, capable of resisting the immense pressure of the water during the height of the floods, were raised, and the whole edifice was at length completed with great rapidity by the aid of many thousand workmen, just before the rise in the Nile occurred.  The official opening of the dam took place on the 10th of December, 1902.