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19-03-2015, 15:15

Environmental Setting

The most important natural resource in Egypt, in ancient times as well as modern, is the Nile River. Reflecting the importance of the Nile, the Egyptians from the Middle Kingdom on called their land Kemet, which means the “Black Land” of the floodplain where they cultivated their crops, in contrast to the deserts to either side, which were known as Deshret, the “Red Land” where any kind of cultivation was impossible.



Without the Nile, there would have been no fertile valley in which ancient Egyptian civilization could have arisen. Cereal agriculture, which was introduced into Egypt from southwest Asia (see 4.8), was the economic base of pharaonic Egypt. The special environmental and climatic conditions of the Egyptian Nile Valley greatly enhanced the productivity of emmer wheat and barley cultivation without the long-term problems (especially salinization) that threatened agriculture elsewhere in the ancient Near East. Cereal agriculture thrived in Egypt as nowhere else in the ancient world. What the farmers grew fed everyone else - not only the king and elite, but also all of the full-time workers employed by the state, from bureaucrats to laborers who built the royal tombs and cult temples.



Unlike agriculture in North America and Europe, rainfall is not a significant factor for cultivation in Egypt. The annual flooding of the Nile provided the needed moisture for cultivation on the fertile floodplain. Most of the water of the Nile originates far to the south of Egypt in highland Ethiopia, beginning as heavy rains there from June to sometime in September. Daniel Eugene Stanley, a geologist at the Smithsonian Institution who has analyzed deposits of silts at the mouth of the Nile Delta, has shown that most of these silts came from Ethiopia, carried via the Blue Nile, which originates at Lake Tana in northern Ethiopia. The Atbara River, which feeds into the Nile at Atbara in northern Sudan, also begins in highland Ethiopia, but the Blue Nile has a far greater volume of water. Flowing rapidly through high altitude, mountainous regions in northern Ethiopia, the Blue Nile and Atbara River have created deep canyons and much of their water passes directly into the Nile.



The White Nile, which originates in Lake Victoria in northern Tanzania, also provides some of the water of the Egyptian Nile (about 10 percent). But some of the volume of the White Nile does not reach Egypt. It is lost in a huge swampy region in southern Sudan known as the Sudd, where the flow of the river is sluggish and much evaporation occurs.



The confluence of the Blue and White Niles is at Khartoum, the modern capital of Sudan in the northern part of the country. From Khartoum northward the river is called the Nile. North of Khartoum there is little seasonal rainfall, although the northern extent of the rainfall belt, which first brings rains to northern Ethiopia, can change periodically.


Environmental Setting

Map 3.3 Northeast Africa.



Between Khartoum and Aswan in southern Egypt there are six (numbered) cataracts, bands of igneous and metamorphic rocks which intersect with the river, creating shallows and rapids that impede boat traffic. This region of the Nile is known as Nubia, corresponding to where some Nubian languages were spoken from late antiquity onward. Above (south of) the Second Cataract there is a stretch about 160 kilometers long called the Batn el-Hagar (“Belly of Rocks”), where the rocky river bed makes navigation difficult or treacherous for much of the year except during the flood season. About midway between the Second and Third Cataracts there is also another cataract known as the Dal Cataract. Cutting through soft sandstone bedrock in Nubia, the Nile has a narrow floodplain until about 100 kilometers north of Aswan in Egypt proper. This greatly limits the agricultural productivity in most of Nubia, and the deserts on either side are some of the hottest and driest regions in the world.



The Egyptian Nile Valley, from Aswan to the apex of the Delta in northern Egypt, is a much more homogeneous stretch of the river, with no cataracts to impede navigation and communication along the river. Navigation downstream was with the current, while navigation upstream by sailboat was greatly enhanced by the prevailing northerly winds. But as John Cooper has recently demonstrated, navigating on the Nile before modern dams were built could be difficult - especially after the annual floods were finished.



Broad floodplains, up to 25 kilometers across, are characteristic of much of the Egyptian Nile Valley and are ideally suited for large-scale cereal cultivation. In cross-section the river in Egypt is a deep channel, with floodplains to either side. As Karl Butzer, a geomorphologist at the University of Texas, has emphasized, the Nile Valley is a slightly convex type of floodplain, with natural levees that rise above parts of the floodplain and often remain dry during the seasonal inundation. The levees divide the floodplain into flood basins, which are where crops were cultivated in pharaonic times. Ancient settlements were located on levees within the floodplain or at the edge of the floodplain. There were also low-lying areas beyond the floodplain, near the desert edge, which retained moisture and were good grazing places for domesticated animals.



The Egyptian Nile Valley is a very circumscribed environment, with farming possible in ancient times only on the floodplains. The present course of the river is not the same as it was during pharaonic times. For example, investigations in the Giza-Saqqara region have demonstrated that the river flowed much farther west (and closer to the pyramids) than it does today. Beyond the fertile silts and seasonally moist soils of the floodplain is the low desert, where almost nothing grows. Immediately beyond that is the high desert, consisting of limestone cliffs and hills, where tombs were excavated in the bedrock, or limestone plateaus, which provided a solid bedrock base for pyramid construction.



In the northernmost part of Egypt, the Nile Delta is a somewhat different environment from the Valley. With more river channels, the Delta is not such a highly circumscribed environment as the Valley. In the winter there are Mediterranean rains, some of which reach the Cairo region. In pharaonic times some of the Delta was used for animal grazing, including government-controlled pasturage where cattle and sheep were fattened. There was also seasonally flooded land in the Delta suitable for farming, while settlements were located on low, sandy knolls called turtlebacks that rose above the floodplain.



Since the High Dam at Aswan was built in the 1960s, the environment of the lower Nile Valley has changed. Flooding no longer occurs annually, but as needed throughout the year for perennial cultivation. The dam prevents the destruction of villages and towns in Egypt, which sometimes occurred when the annual flooding was too high. Too low floods, which decrease the amount of land under cultivation and thus total agricultural yields, are also prevented by the dam. But nutrient-rich silts brought downstream are now blocked behind the dam, and huge amounts of artificial fertilizer need to be used in Egypt.



The annual flooding used to flush out salts in the soil, which increase when fields are irrigated and evaporation occurs. Without the yearly inundation there is now much more salt in the ground water. Ground water is also higher now in the lower Nile Valley, which is a major problem for ancient stone monuments. As ground water percolates up into ancient building stones, it evaporates, leaving salts in the stone, which will eventually weaken and crumble.



 

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