22-09-2012, 03:20 PM
ANCIENT HYDRAULIC STRUCTURES
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OVERVIEW
Since the Egyptian’s and Mesopotamian’s first successful efforts to control the flow of
water thousands of years ago, a rich history of hydraulics has evolved. Sec. 1.2 contains a
brief description of some ancient hydraulic structures that are found around the world.
During the 20th century, many new developments have occurred in both theoretical and
applied hydraulics. A number of handbooks and textbooks on hydraulics have been published,
as indicated in Fig. 1.1. From the viewpoint of hydraulic design, however, only
manuals, reports, monographs, and the like have been published, mostly by government
agencies. Unfortunately, many aspects of hydraulic design have never been published as
a compendium. This Hydraulic Design Handbook is the first effort devoted to producing
a comprehensive handbook for hydraulic design. The book covers many aspects of
hydraulic design, with step-by-step procedures outlined and illustrated by sample design
problems.
ANCIENT HYDRAULIC STRUCTURES
A Time Perspective
Although humans are newcomers to earth, their achievements have been enormous. It was
only during the Holocene epoch (10,000 years ago) that agriculture developed (keep in
mind that the earth and the solar system originated 4,600 million years ago). Humans have
spent most of their history as hunters and food-gatherers. Only in the past 9,000 to 10,000
years have humans discovered how to raise crops and tame animals. Such changes probably
occurred first in the hills to the north of present-day Iraq and Syria. The remains of
the prehistoric irrigation works in Mesopotamia and Egypt still exist. Table 1.1 presents a
chronology of knowledge about water.
Figure 1.2 illustrates the chronology and locations of various civilizations ranging
from India to Western Europe. This figure, from O. Neugebaur’s book titled The Exact
Sciences in Antiquity, illustrates the Hellenistic period the era of “ancient science,”
during which a form of science developed that spread later from Europe to India.
This ancient science was dominant until the creation of modern science dominant in
Isaac Newton’s time.
Irrigation Systems
1.2.2.1 Egypt and Mesopotamia. In ancient Egypt, the construction of canals was a major
endeavor of the Pharaohs beginning in Scorpio’s time. Among the first duties of provincial
governors was the digging and repair of canals, which were used to flood large tracts of land
while the Nile was flowing high. The land was checkerboarded with small basins defined by
a system of dikes. Problems associated with the uncertainty of the Nile’s flows were recognized.
During high flows, the dikes were washed away and villages were flooded, drowning
thousands of people. During low flows, the land was dry and no crops could grow. In areas
where fields were too high to receive water directly from the canals, water was drawn from
the canals or from the Nile by a swape or shaduf (Fig. 1.3), which consisted of a bucket on
the end of a cord hung from the long end of a pivoted boom that was counterweighted at the
short end (de Camp, 1963). Canals continued to be built in Egypt throughout the centuries.
Dams
The Sadd-el-Kafara dam in Egypt, situated on the eastern bank of the Nile near Heluan
approximately 30 km south of Cairo, in the Wadi Garawi, has been referred to as the world’s
oldest large dam (Garbrecht, 1985). The explorer and geographer George Schweinfurth
rediscovered this dam in 1885, and it has been described in a number of publications since
that time (see Garbrecht, 1985). It was built between 2950 and 2690 B.C. Although the Jass
drinking-water reservoir in Jordon and the diversion dams on the Kasakh River in Russia are
probably older, they are much smaller than the Sadd-el-Kafara (Dam of the Pagans).
It is unlikely that the Sadd-el-Kafara dam was built to supply water for drinking or irrigation
because the dam lies too far from the alabaster quarries situated upstream to have
supplied the labor force with drinking water. Furthermore, there is a vast supply of water
and fertile land in the nearby Nile valley. The apparent purpose of the dam was to protect
installations in the lower wadi and the Nile valley from frequent, sudden floods. The dam
was destroyed during construction by a flood; consequently, it was never completed. To
date, the dam’s abutments still exist.