The river's silt-brown waters turned flashing gold in the first sunlight of a new day. To the farmer on the riverbank it was a sight filled with vivid memories, familiar signs and ancient questions.
The farmer saw that the river (later called the Euphrates) had risen during the night. He was reminded of a saying his father had taught him. On a morning like this his father had told him he was now old enough to learn the secrets of the river and how it gave life to the desertlands. "Water," the father had begun, "like fire, is a good friend but a bad enemy. On desertlands, water is the strongest power the gods hold over man."
Words spoken father-to-son 7,000 years ago held the wisdom the people lived by. Not for another 1,500 years would the written word be invented, but word-of-mouth lessons about how to keep life going were the richest inheritance each generation gave the next.
The farmer could tell by the sun's position on the horizon and the rise of the river that the flood season would come soon. By such signs, knowing nothing of calendars, he and the people of his village marked the seasons. They would have welcomed better ways to forecast nature's changes and moods, because in this arid land survival depended on advance preparations for too much water or too little.
A small song bird added its music to the murmur of the river. Here at the lower reaches of the Euphrates he and his friends were regular visitors when the warm days returned. The bird's arrival was another warning. Upriver the floods might have started even now.
The farmer noted these signs. This year the village had chosen him to organize the river watch. If the gods were angry this season, and the watch under his leadership failed to give the alarm, the village would make him pay, perhaps with his life. It was a harsh custom, but when the life of the village was entrusted to those on guard, there seemed no other way.
On this sunlit morning such dark thoughts did not stay long. Tradition gave an extra section of land to the man in whose hands the village put its safety. It was better to think about the larger harvest the farmer would enjoy.
True, some in the village said the watch leader's fields were larger than he deserved. That was to be expected. But the farmer had no real fear that talk would do him out of his land, although after the floods it might be hard to find. Many of the dividing lines would be washed away or buried under mud. The mud, river-borne silt from the faraway mountains, brought new fertility to the soil. That was good. It also brought a new round of dispute to the village. That could not be helped. After the floods the redivision of the lands, without arithmetic or geometry, was a makeshift chore that too often left hard feelings.
The farmer, by later standards, did not know much. But compared to the past rather than the future, his people were wealthy in farming knowledge. Their skill provided the village with wheat, barley and peas. Sheep and goats were raised for their wool, meat and milk. At about this time cattle were coming into use among farming peoples, for meat, milk, hides and their strength as beasts of burden. Ox-drawn plows and wheeled carts were replacing planting sticks and back-packs.
In other ways the villages along the Tigris and Euphrates were not typical—because they were on the desert. Farming began where crops could be grown by rainfall alone, in the highlands of the Fertile Crescent. This belt of moderate but adequate rainfall starts at the northwest corner of the Arabian Peninsula and sweeps north inland from the Mediterranean, then curves north and east through the elevated lands at the headwaters of the Tigris-Euphrates rivers, and turns southeast to touch the Persian Gulf. The lands lying generally to the south of this crescent are semi-arid or dry-as-dust desert. They include a large part of the Arabian Peninsula and most of the Tigris-Euphrates valleys. The desert soils in this region are often highly fertile. But without the addition of water they cannot grow the quantities of food needed to support large communities.
The farmer's village and others like it owed their existence to a hard-won answer to a difficult problem.
Here was born the idea of irrigation, in the arc of semi-desert bordering the higher lands of good rainfall. In the Arabian Peninsula and other parts of this semi-arid crescent, it was discovered that terraced plots could be watered by building catch dams and ditches to collect the run-off from a surrounding watershed. This method for adding run-off to scant rainfall was a big step toward the kind of agriculture later developed along desert rivers like the Tigris, Euphrates, Nile and Indus.
Below the site of the farmer's village, the first settlers saw the marshes at the mouth of the Euphrates as the best place to live. The loam soil was rich and deep. There was no lack of sweet water. In fact, there was too much. Drainage ditches and dikes could keep the water off the land in most seasons. But no earthen structure could fully control the worst floods. So the village itself was built as a refuge on a man-made platform of earth. Even this artificial hill could not escape occasional disastrous floods that might come but once a generation. For insurance against this danger an even higher central mound was constructed. It held the common granary and village temple and was a final point of safety and defense against floods or attempts to rob the village of its food reserve.
This ground plan was a necessity for the village, and later for the first cities, which sprang up along the Tigris-Euphrates valleys. Unlike the Nile, whose annual floods are comparatively gentle and easy to live with, the twin rivers went on rampages capable of wiping out the work of years. The stepped mounds, some of which still can be seen there thousands of years later, were an effective answer to the river's grim challenge.
After these early farmers found a way to avoid being drowned by floods, they had to face another problem: How to get enough water on the land in the growing season.
On the Tigris-Euphrates the floods came many months before the autumn planting season, the summer months being too hot for field crops. The flood-borne silt benefited the land, but for irrigation purposes the river waters had to be tapped at low stage.
The drained marshes could be irrigated by opening the dikes when high tides backed up the rivers and raised their surface levels above the fields. (The two rivers, today joined in the Shatt-al-'Arab, are thought to have been separate for their full lengths in those days.)
Irrigation by tidal power could be carried on easily by each village working alone. But upstream from tidewater each mile added higher obstacles to small-scale irrigation and demanded large-scale systems. For the next 300-400 miles natural levees line both rivers. Further up, above the levees, the rivers have cut their way below the surrounding plains.
The problem, then as now, was how to get water from the river at low stage over the levees or cut banks to the fertile desert beyond. Bucket-chains, -wheels and -sweeps sufficed for small-scale irrigation and have been used for this purpose into modern times.
The farmer's recent ancestors had devised a further improvement. Silt-deposits have raised the river bed and levees so that even low-water mark is usually above the nearby parched earth. The farmer's forebears saw that a cut in the levee would let gravity take the river water to the desert. The plan worked. To harness the resulting man-made flood, a short canal was dug from the cut in the levee along the higher edge of the area to be farmed. Water from the canal flowed with the land's slight grade through a network of irrigation ditches.
A simple idea. But geography made it immensely important. The desert between the Tigris and Euphrates rivers could now be irrigated by canals linking the rivers. Upstream from the levees, dams could raise the waters to the level of the plains. Such gigantic projects would take the manpower of many villages. They would take new skills in engineering and organization. All that was in the future, yet the possibility could now be seen. Thus the irrigation canal was an essential link in a chain of discoveries which led to a change as big as that from the hunter's wanderings to the settled village of the farmer. From this stage in the accumulation of knowledge, invention, like water running down hill, followed a natural course which gave man a new way of life. In generations to come the first cities were built in the Tigris-Euphrates valleys. With them for the first time came the basic civilized arts: writing, astronomy, calendars, arithmetic, geometry, construction, engineering, architecture, food distribution, law and government.
Neither the farmer nor his descendants could imagine the civilized arts which were to crown their pioneering efforts. They could see no further into the future than the need to support a population which increased as much as the food supply allowed. But it was that ever-increasing food supply, won by taming the flood waters, that allowed the famous cities of the Fertile Crescent to prosper—to become, in fact, the "cradle of civilization."