摘要: Description　　Physically, the Oasis corresponds to a depression dug in the limestone rock with a surface area of about 17.000 km2, whose bottom lies 45 m below sea level and the surrounding relief rise

Description

　　Physically, the Oasis corresponds to a depression dug in the limestone rock with a surface area of about 17.000 km2, whose bottom lies 45 m below sea level and the surrounding relief rises 350 metres above sea level. To the north, a lake called Lake Qaroun, spreads over 40 km in length and is 4 km wide at some points, thus covering about 200 km2. That is all that is left of the "inland sea" which, during the upper Pharaonic period, still inundated most of the Fayoum lands so that the latter was known as the "Country of the Lake". Herodotus, who visited it in 460 BC, spoke of "Lake Moeris" which seems to correspond to a smaller lake, perhaps not as shrunk as the one today, but certainly not the "inland sea" of remote times.

　　What could have happened between the upper ancient period and the Vth century BC which could explain such a remarkable change, reducing the vast stretch of water to less than 20% of its ancient surface area?

　　Erstwhile the water reached the Fayoum only through the Bahar Youssef canal, (the Hassan Wassif opening is more recent) then it ramified through a large network covering the whole area. Not so long ago the water was evacuated only into the Qaroun Lake until the recent addition of the Wadi Rayyane depression.

　　Historical aspect:

　　In prehistoric times the Fayoum had a vast depression which received, through one of the branches of the Nile, the Bahar Youssef which rises from the north of Assiout, the river's overflow when it was in spate formed the ancient "inland sea". Only a central plateau emerged, the rest being bushes and marshes covered with luxurious vegetation and inhabited by an abundant and varied fauna. Settlements sprung up very early on (prehistoric studies yielded information on the life style of the inhabitants at the end of the Paleolithic and Neolithic) who developed their own cultures known as the cultures of Qaroun (8100 BC), Fayoum and Moeris (Vth and IVth millenium BC). Prehistorians classified the Fayoum among the first regions of Northern Egypt where agriculture was practised.

　　These settlements arose during the pre-dynastic periods and during the Old Empire when the sovereigns provided incentives to encourage agriculture.

　　It was, however, with the XIIth dynasty, when Egypt's capital was transferred to Lishte, a place quite close on the Nile, that there was renewed interest in the region from the country's rulers because of its enormous agricultural potential and a considerable amount of work was done to develop the area. The work was started by Senusert II (1872-1854) and completed by his grandson Amenemhat III (1853-1809); the Bahar Youssef was channelled and a network of irrigation canals was set up. This doubtlessly also made it possible to protect the Fayoum from the Nile's devastating floods and to gain agricultural land to the detriment of the "Inland sea".

　　The first to have drawn attention to this hydraulic undertaking and colossal drainage operation and who described it in the Vth century with great admiration, was Herodotus. This was indeed one of the oldest experiences of this magnitude and perhaps even the oldest of all time, never achieved before, about 3850 years ago, with no comparison whatsoever, except for contemporary hydraulic works, or later works on the Tigris and Euphrates in Mesopotamia. Strabo in 24 BC described how the water of the Nile was channelled and distributed and already in his time the system had been greatly improved by the Ptolemies, who, in their turn, undertook great drainage and further development works.

　　Amenemhat III deified "The magnitude of the great works undertaken by Amenemhat in the Fayoum as well as the size of the monuments he left (his funerary temple of Hawara and the famous labyrinth of the Greek travellers) made such an impression that, confusing his coronation name of Pramarres with the quite similar name of Lake Moeris, the Greeks attributed the digging of the lake to him".Amenemhat III, the genius behind the development of the "country of the Lake" was deified by the Ptolemies (about 15 centuries after his death) who in turn were interested again in the Fayoum, drained it definitively and at the same time developed its agriculture and its economy, especially under Ptolemy II (285-246 BC).The Fayoum thus became one of Egypt's richest agricultural areas where Strabo could see the only olive groves in the country and taste the wine which was produced there in abundance. On a curious monument dating from that period and found in Kisnan Fares (Medinet El Fayoum), the deified Amenemhat III is shown together with the crocodile god Sobek (a local deity of Fayoum), the baboon of Thot and the hippopotamus of Thoueris. The deified king was thus placed on an equal footing with the other gods, all linked in one way or another, with the waters of the life-giving Nile". (according to a text by Jean-Pierre Corteggiani, Egyptologist.

　　The Egyptians of the IIIrd century BC thus in their own way acknowledged this tremendous technical feat with its great impact in the Fayoum and in Egypt and possibly in the outside world as well.

　　The works started with the XIIth dynasty, further developed during the period of the Ptolemies who, it seems, added 1200 km2 of arable land, did not stop with that dynasty but continued during the Roman period when there was a need for new lands and other marshy areas on the banks of the lake had to be reclaimed especially during the 1st and IInd century AD leading to a renewed shrinking of the prehistoric lake.

　　The Greco-Roman period was one of the most prosperous in the history of the Fayoum because of the prosperity of its numerous agricultural villages (known as the villages of Sobek, the crocodile god of the region) whose lands had first been drained and then irrigated by channels fed by the great Bahar Youssef canal. This period of plenty was however followed by a period of decline (from the IIIrd century on) leading to the abandonment of several towns and villages of the Fayoum in the IVth century and doubtlessly also to the deterioration of the hydraulic system. The Arab conquerors, from the middle of the VIth century and during the whole of the Middle Ages, had to undertake great restoration works to clear the blocked canals, dig other ones, build dykes, dredge flooded areas and build bridges. The historians and chroniclers of that time referred to these works and there are some dated remains visible such as those undertaken when the Lahoun was opened at the beginning of the XIIIth century in the Bahar Youssef canal and the neighbouring bridge which spans the canal. Thanks to the works completed under the Mameluke Sultans in the XIIIth century then under Mohamed Ali in the XIXth century, the Fayoum became once more the "garden of Egypt". The XIXth century brought two problems with it, overpopulation and salination. Lake Qaroun, what is now left of the great prehistoric lake fed by the great Nile, is today just as saline as the Mediterranean.