Hello there
Well, first of all, it may surprise you to learn that not that many
materials were involved in the Sumerian irrigation systems. It was
constructed by simply moving dirt to make channels for the water to go
through.
Unlike many other places where irrigation was used and water had to be
lifted from a river or lake to spread on the fields, in ancient
Sumeria, the rivers were actually higher than the surrounding fields
because of silt build up forming a natural levee along the banks. It
was simply a matter of cutting an opening in the levee and allowing
water to flow over the fields.
Irrigation eventually destroyed the ability to raise crops in the
area. When looking at the arid waste there now, it is hard to believe
that the region was once lush and green. However, the very act of
irrigation poisoned the soil.
There was no way to drain away the water once it was on the fields
since they were lower than the river. As it evaporated, it left a
load of salts behind and also drew salt upward from deeper layers of
soil. By about 2300 BCE, agricultural production in Sumeria had
dwindled to almost nothing. Most of the regions fields were abandoned
as worthless.
As an archaeologist, I am aware that there are history sources which
claim Sumerian irrigation was accomplished by the use of shadufs,
canals, channels, dikes, weirs, and reservoirs. They are being rather
generalized in their statements. All of those things were eventually
used in the Mesopotamian region, but by later civilizations rather
than the Sumerians, and your question is specific about the Sumerians.
The shaduf was not invented till much later by the Egyptians. Canals
and channels were accomplished simply by the movement of earth, no
other real materials were used except for perhaps a palm log to block
a channel when needed. Dikes were simply earth moved to the side of a
channel and weirs were earth built diversionary structures similar to
dams. Once again, no outside materials were needed. And as for
Sumeria, the rivers themselves were the reservoirs.
From time to time catastrophic floods overwhelmed the region. At Ur
there is a well-known band of 1.5 m of clay between two layers of
pottery. This is evidence of a major flood, and this event was
probably the basis for the flood story in the Sumerian Epic of
Gilgamesh and for the much later Biblical story of the Flood.
It was not till about 1000 BCE that the large scale irrigation
projects were undertaken which drastically moved water to where it was
needed. By the time these large scale projects were underway, which
did include wood, stone and other materials, the Sumerian civilization
was already long gone from history and replaced by Babylon and others.
In fact, one of the major accomplishments of the later system had to
do with draining the fields to prevent salt build up. By this time
the irrigation systems were enormous. Although the plain of
Mesopotamia is very flat, the bed of the Euphrates is higher than that
of the Tigris. In fact, Euphrates floods sometimes found their way
across country into the Tigris. Engineers used this gradient as soon
as irrigation schemes became large enough, using the Euphrates water
as the supply, and the Tigris channel as a drain.
Since there was no 'real' construction in the Sumerian irrigation
system other than earth movement, and allowing water to run down hill
from the river to the fields, an "example" would be most anything that
displayed that simple principle.
Search - Google
Terms - mostly first hand knowledge - but since you will probably need
some backup sources, here are some websites you can use.
First I will give you "Ennugi" No, that is not something I do to the
top of your head. It is an ancient poem which describes the process
of Sumerian irrigation. It is simply moving and carrying dirt.
Ennugi was the canal-controller, mentioned in the Mesopotamian poem of
Athrahasis. Here is the full text:
http://www.dow.wau.nl/iwe/ennugi/research/mesopotamia.htm
"Why do Civilizations Fall?" - You will find an overview explaining
how Sumerian and other Mesopotamian irrigation practices caused the
poisoning of the land.
http://www.learner.org/exhibits/collapse/mesopotamia.html - From Annenberg/CPB
"Mesopotamian Farming" - Actually this is a very brief set of notes
about Mesopotamian farming which only touches briefly on Sumer.
"Archaeolink.com" - I must identify this as my own website. Scroll to
archaeology> middle east or to ancient civilizations>middle east to
access a few dozen sites and articles about the Mesopotamian region.
Sumer has a section of its own.
http://www.archaeolink.com/
When dealing with ancient farming and irrigation practices in this
part of the world, it is often difficult to separate Sumer from the
later periods as so many historians (rather than archaeologists) have
a tendency to lump Sumer and later civilizations such as Babylon,
Assyria, etc, all together. I hope the above has helped in your
project.
If I may clarify anything, please ask
Cheers
digsalot |
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