The great Nile dam, at the head of the first cataract of the Nile, is 600 miles above Cairo. The dam was built 1898 - 1902 by the Egyptian government for irrigation, the water being utilized for that purpose between May and July, when the river is at its lowest and before the annual inundation begins in the middle of July. The dam is 1-1/4 miles across and is built of Assuan granite laid in Portland cement. On the dam are 180 sluices which have a capacity of emitting 15,000 tons of water per second. It holds 1,000,000,000 cubic meters of water. The dam is filled with the muddy flood coming down from the mountains, and opens again when the Nile is low. As the water lies in the dam, the mud sinks; but as the outlets are along the bottom, when the water goes out it carries the mud with it, and thus distributes it through the canals to farm after farm. The dam has now a maximum height of 130 feet, and at the base is 100 feet thick and 30 feet at the top. The summer rains in Abyssinia raises the level of the Nile in a great flood, the crest of the wave arriving in lower Egypt in October. As soon as the water recedes the grain is planted in the rich soil. The homes are built on the highest land beyond reach of the water. With the exception of the palm tree and the fringe vegetation along the river, there is an absence of the abundant plant life of the regions having suffered sufficient rainfall.
The Nile River has its source in the highlands near the equator, having its source in Lake Victoria, about 4000 feet above sea level. The river is the longest in Africa. It pours out of Lake Victoria and races for hundreds of miles through rapids and cataracts, then flows more slowly over plains until it reaches the Sahara, through which it winds its way, spreading out into a wide fan where it empties into the Mediterranean Sea. Along the banks of the Nile the land is very fertile, so that Egypt has always been regarded as a grain-producing country. But in spite of the fact that the soil is rich, there is, nevertheless, a remarkable lack of varety in the trees of the country. Egypt has in reality only one kind of tree, which may be regarded as characteristic of the Egyptian landscape, and that is the shadowy palm tree. For timber Egypt has always been obliged to send abroad. In ancient times it was especially customary to make an expedition to the Lebanons and bring back cedar and sycamore wood for building purposes. Though palms cannot furnish the country with the necessary timber, yet they spread, and thus give protection against the burning sun. The stem of the palms is often used in the production of ropes.
The Sakka, or water-carrier, with his goatskin of water, carried either by himself or by a donkey, still plies his trade in Cairo, although the water works supply every house in the city, as well as the public sebils (fountains) with water, and though on many houses there are brass tubes through which passers-by may take a draught from the main pipes.