Irrigation Systems, Ancient - Dam, Building, River, Important, Salt, Source

Irrigation in Egypt and Mesopotamia

The first successful efforts to control the flow of water were made in Mesopotamia and Egypt, where the remains of the prehistoric irrigation works still exist. In ancient Egypt, the construction of canals was a major endeavor of the pharaohs and their servants, beginning in Scorpio's time. One of 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 regarding the uncertainty of the flow of the Nile were recognized. During very high flows, the dikes were washed away and villages flooded, drowning thousands. During low flows, the land did not receive water, and no crops could grow. In many places where fields were too high to receive water from the canals, water was drawn from the canals or the Nile directly by a swape or a shaduf. These consisted of a bucket on the end of a cord that hung from the long end of a pivoted boom, counterweighted The Nile River has played an important role in the lives of Egyptians throughout history. This frieze (c. 2000 B.C.E. ) depicts Egyptians using water from the Nile River for irrigation. at the short end. The building of canals continued in Egypt throughout the centuries.

The Sumerians in southern Mesopotamia built city walls and temples and dug canals that were the world's first engineering works. It is also of interest that these people, from the beginning of recorded history, fought over water rights. Irrigation was extremely vital to Mesopotamia, Greek for "the land between the rivers." Flooding problems were more serious in Mesopotamia than in Egypt because the Tigris and Euphrates carried several times more silt per unit volume of water than the Nile. This resulted in rivers rising faster and changing their courses more often in Mesopotamia.

Both the Mesopotamian irrigation system and that in the Egyptian delta were of the basin type, which were opened by digging a gap in the embankment and closed by placing mud back into the gap. Water was hoisted using the swape, as in Egypt. Laws in Mesopotamia not only required farmers to keep their basins and feeder canals in repair but also required everyone to help with hoes and shovels in times of flood or when new canals were to be dug or old ones repaired. Some canals may have been used for 1,000 years before they were abandoned and others were built. Even today, 4,000 to 5,000 years later, the embankments of the abandoned canals are still present. These canal systems, in fact, supported a denser population than lives there today. Over the centuries, the agriculture of Mesopotamia began to decay because of the salt in the alluvial soil. Then, in 1258, the Mongols conquered Mesopotamia and destroyed the irrigation systems.

The Assyrians also developed extensive public works. Sargon II, invading Armenia in 714 B.C.E. , discovered the qanat (Arabic name) or kariz (Persian name), which is a tunnel used to bring water from an underground source in the hills down to the foothills. Sargon destroyed the area in Armenia but brought the concept back to Assyria. This method of irrigation spread over the Near East into North Africa over the centuries and is still used. Sargon's son Sennacherib also developed waterworks by damming the Tebitu River and using a canal to bring water to Nineveh, where the water could be used for irrigation without hoisting devices. During high water in the spring, overflows were handled by a municipal canebrake that was built to develop marshes used as game preserves for deer and wild boar, and birch-breeding areas. When this system was outgrown, a new canal, nearly 19 kilometers (30 miles) long, was built, with an aqueduct that had a layer of concrete or mortar under the upper layer of stone to prevent leakage.