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The Epic Interactive Encyclopedia 1996
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Epic Interactive Encyclopedia, The (1996)(Epic Marketing)[non-bootable].iso
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d
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dam
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1992-09-02
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933b
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A dam is a structure built to hold back water
in order to prevent flooding, to provide
water for irrigation and storage, and to
provide hydroelectric power. The biggest dams
are of the earth and rock types, these are
also called embankment dams. The underground
dam is where water is stored on a solid rock
base, with a wall to ground level, this
avoids rapid evaporation.
Many concrete dams are triangular in cross
section, with their vertical face pointing
upstream. Their sheer weight holds them in
position, these are commonly called gravity
dams. Other concrete dams are more slightly
built in the shape of an arch, with the curve
facing upstream, the arch dam derives its
strength from the arch shape.
The earliest dam in Britain is at the Roman
Dolaucothi gold mine in Dyfed, Wales, dating
from the 1st century AD. The first major
all-concrete dam in Britain was built at
Woodhead in 1876.
Subject by: Vince Pike