The Medjerda (rear RTL مجردة) is a Fleuve mainly Tunisia N.

Geography

It takes its source close to Souk-Ahras (in Constantinois Algérie N) then runs towards the east before being thrown in the Mediterranean (Golfe of Tunis). Running out on more than 416 kilometers of which 350 in Tunisia, it is only and the longest perennial river of Tunisia even if it has a irregular Débit, energy of: 1000 to 1 m·S − 1 , because of the multitude of Wadi S with irregular flows by definition like the Wadi Mellègue.

Thanks to the richness of its alluvia, the Vallée of Medjerda is one of the most fertile grounds of Tunisia and represents it twelfth of its water resources. This is why the river is equipped with several Barrage S hydroelectric. Medjerda is in addition a crucial water way for the Irrigation and thus plays a big role for the regional Agriculture.

Medjerda carts each year approximately 800 million cubic meters of water but also some 20 million tons of ground, removed by erosion, which settle when the river reached the low areas and punts of its lower course. One then attends a general raising of the reads, whose banks end up dominating the Plaine, and to his lengthening by a Delta which advances gradually on the sea. Instability, resulting from what the river runs between its Berge S, conduit with frequent changes of bed (five known to date) and with an increasing difficulty for the water run-off in a zone more and more punt.

History

This strategic role pushed with the foundation of the towns of Utique, Carthage and Tunis near the river. This last is known Romains under the name of Bagradas . It is close to sound Golfe that Régulus, according to Pline Old the ( Natural history , VIII, 14), would have killed a Serpent of 200 feet length.

The gulf of Utique, in which the river was thrown, is formed during the postglacial period (there is approximately: 6000 years). With the wire of time, the deposits of alluvia gradually fill the northern part of the gulf. The sea is withdrawn some gradually starting from the Moyen-âge. The southern part of the gulf as for it is filled more recently. This succession of events was deduced from old documents and archaeological traces. Moreover, aerial observations and satellite were used in order to analyze the evolution of the landscape during: 3000 last years. The Lagune of Ghar El Melh is the last vestige of what was the gulf of Utique. Following the Crue S of February 1937 which cause extensive damage of any nature, it is created an Office of the development of the valley of Medjerda in charge of the fight against the Inondation S, the cleansing and the drainage, the defense and the restoration of the grounds, the network of irrigation and the agricultural experimentation (station of Sidi Thabet). Derivation by Henchir Tobbias, which divides the flow of Medjerda starting from 1939 and reduces its course of 15 kilometers, becomes its current bed as of 1973.

Stoppings

Medjerda is equipped with several stoppings. Among them, one finds those of Sidi Salem (the largest stopping of the country) and of El Aroussia. This last, which is of river type to three sluices, has an hydroelectric station and of a hydrant intended for the irrigation of 50.000 Hectare S. Its realization spread out between 1952 and 1957.

Crossed cities

Some cities crossed by Medjerda of upstream downstream:

• Souk-Ahras (Algeria)

• Jendouba (Tunisia)
• Bousalem (Tunisia)
• Testour (Tunisia)
• Medjez el-Bab (Tunisia)
• Tebourba (Tunisia)
• Djedeida (Tunisia)