The Water beneath the Egyptian Western Desert

This paper adheres strictly to the textbook definition of as that derived from springs which rise above the surface of the ground by natural hydrostatic pressure, as they do in Artois in France. That is to say, the numerous deep wells sunk through the mud of the Nile Valley into the sands and gravels beneath do not qualify for the description artesian since the supplies they tap lie well below the surface and the water therein has to be raised by pumping. Practically the whole of the water below the fields of the Nile Valley and the Delta is derived from the river itself. Naturally, its flow through the sands is slower than that of the free-flowing Nile; and so it has come about that a summer supply can be obtained from these beds when the river itself is too low to fill the canals which take off from it. But this supply has to be raised by pumping and so has no right to be called, though in Egypt it commonly is, artesian. Below the First Cataract the Nile has cut its channel through a series of sedimentary and mainly porous beds, and the river water that enters them seeps away at a steep slope on either side, so that a bore sunk at any distance from the cultivation has a poor chance of striking the Nile water table at a depth profitable for exploitation. The Nile is thus losing water to the desert nearly everywhere along its course. For this loss the compensations are slight. After rain, the river is sometimes discoloured by muddy water which has rushed from the hills of the Eastern Desert down the wadis to the Nile. And at all times, there are small seepages below ground down the courses of these normally dry tributaries. But the total amount of Egyptian rainfall is so small that its contribution may be absolutely disregarded in any estimate of the Nile discharge.