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and 4 metres high. It ran between two groups of rocks on either side of the river
and was linked to the rock with substantial stonework (Fig 1.3).
The dam's position allowed for a spillway and sluices between the northern end
of the dam and the cliffs to the west. Around 500 BC the dam height was increased
to 7 metres, the upstream slope (the water face) was reinforced with a cover of
stones, and irrigation was extended to include the southern side as well as the
northern side. After the Kingdom of Sheba, possession of the dam came to the
Himyarites in around 115 BC, who undertook further reconstruction, raising it to
14 metres high with extensive water works at both the northern and southern ends
with five spillway channels, two masonry-reinforced sluices, a settling pond, and a
1000 metre canal to a distribution tank. These works, completed in 325 AD,
allowed the irrigation of 100 km 2 . The dam suffered numerous breaches and the
maintenance work became increasingly burdensome. Around 570, the dam was
again overtopped, and this time left unrepaired. The final destruction of the dam is
noted in the Qur'an and the consequent failure of the irrigation system provoked the
migration of 50,000 people to the present emirate El Fujeira. 1
According to the Romans stiff soil is masculine and soft soil is feminine.
Archimedes 2 is considered a mastermind and mathematician, inventor of many
mechanical principles, in particular the buoyancy force, important in geotechnics.
Vitruvius 3 , author of Architectura (discovered in the 15 th century) wrote in
Fermitas about soil densification, installation machines for piles, iron
1
In 1986 a new 38 m high, 763 m long, earth dam located 3 km upstream of the ruins of the
old Ma'arib dam was completed across the Wadi Dhana, creating a storage capacity of 400
million cubic metres.
2 Archimedes 287 BC 212 BC, Greek mathematician, physicist, and inventor. His
reputation in antiquity was based on several mechanical contrivances, e.g., Archimedes'
screw; which he is alleged to have invented. One legend states that during the Second Punic
War he protected his native Syracuse from the besieging armies of Marcus Claudius
Marcellus for three years by inventing machines of war, e.g., various ballistic instruments
and mirrors that set Roman ships on fire by focusing the sun's rays on them. In modern
times, however, he is best known for his work in mathematics, mechanics, and hydrostatics.
In mathematics, he calculated that the value of is between 3,1408 and 3,1429, devised a
mathematical exponential system to express extremely large numbers, proved that the
volume of a sphere is two thirds the volume of a circumscribed cylinder, and, in calculating
the areas and volumes of various geometrical figures, carried the method of exhaustion
invented by Eudoxus of Cnidus far enough in some cases to anticipate the invention (17th
cent.) of the calculus. One of the first to apply geometry to mechanics and hydrostatics, he
proved the law of the lever entirely by geometry and established Archimedes' principle. In
another legendary story, the ruler Hiero II of Syracuse requested him to find a method for
determining whether a crown was pure gold or alloyed with silver. Archimedes realised, as
he stepped into a bath, that a given weight of gold would displace less water than an equal
weight of silver (which is less dense than gold); and he is said, in his excitement at his
discovery, to have run home naked, shouting Eureka! (I've found it! I've found it!). A
Roman soldier killed him, supposedly while absorbed in mathematics.
3
Marcus Vitruvius Pollio (ca 90 BC - ca 20 BC) Roman architect. He wrote the oldest
extant Western treatise on architecture De Architectura or the Ten Books. An invaluable
document of Roman and Greek architectural history and building practices; its discovery in
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