John Peter Oleson
Irrigation involves intentional enhancement of the natural water supply to orchards or crop land, or the provision of water where none is available naturally. In Antiquity, as today, land was irrigated only where necessary. In consequence, irrigation activities varied in their intensity—depending on the climate and the crops—as well as in technique, which depended for the most part on topography and hydrology. In his discussion of the differences between Egyptian and Greek life, Herodotus focuses on the provision of water to agricultural land (II 12–13).
When they learned that all the land of the Greeks is watered by rain
and not irrigated by the river, like their own, the Egyptians said that
the Greeks would someday be deceived in their high hopes and suffer
terrible starvation. What the Egyptians said about the Greeks was true
The Egyptians were astonished that anyone should rely completely on such an unpredictable source of water. In Egypt, as in Mesopotamia, irrigation was necessary virtually everywhere for agricultural activity, and great exogenous rivers supplied an abundance of water. Greece, although lacking in ground water, received sufficient precipitation to allow the drought farming of grain crops and fruit trees, and irrigation was applied almost exclusively to vegetable gardens. In Italy, by contrast, drainage was as big a concern to the farmer as irrigation, which was applied for the most part only to vegetable gardens or, occasionally, to enhance the quality of a field crop.
Mesopotamia and Egypt, in fact, were exceptional among the ancient cultures considered here in their extensive use of constant, river-based irrigation. Elsewhere, a variety of techniques and strategies were employed to make the best use of the available precipitation. In the desert lands that became the Provincia Arabia, for example, techniques for harvesting the infrequent precipitation allowed