WATER PROBLEMS AND DEVELOPMENTS OF THE PAST1

Abstract

ABSTRACTPresent‐day climatic conditions of the Earth were reached between 5,000 and 8,000 years ago. These are essentially the conditions under which the earliest civilizations arose. Ancient basic water problems were the same as those of today, and remarkable technologies for coping with these problems were developed. Few water technologies, except for water treatment, are modern creations.Dry farming began about 8000 B.C. Irrigation began about 5000 B.C. and became extensive by about 3500 B.C., principally in Mesopotamia, the Nile Valley of Egypt, and the Indus Valley of Pakistan. Ancient irrigators developed ingenious structures for obtaining groundwater without the use of wells or sweeps. One device, the Khanat (a kind of infiltration gallery), is still widely used in the Mediterranean area, southwest Asia and China. The khanat was invented during the First Millenium B.C.Ancient peoples also learned to collect surface runoff in areas of scanty precipitation and to use it for local groundwater recharge. The water was recovered from dug wells and used for domestic supply and stock watering.Damming of rivers began at least by the early part of the First Millenium B.C. in the Arabian Peninsula. Most early dams were for irrigation but some were also for city water supply. Many canals in various areas served the dual purposes of water supply and navigation.Soil and water salinity have been persistent problems throughout the history of irrigation and we still have not solved these problems.Irrigation practices were developed independently in the New World but much later than in the Old. North American Indians in some areas still follow the ancient practices. The chinampa system, still used in Mexico, is one of the most intensive methods of farming ever devised.Ancient peoples in the Old World also developed ingenious methods for conserving and increasing soil moisture and for retarding runoff and erosion.During the time of classical Greece and imperial Rome practical water engineering developed to a high degree. Water tunnels, aqueducts, canals, drainage ditches, and dams become commonplace. Even so, water supply and management came relatively late in Europe, where dependence had been largely on natural supply and distribution until the 19th Century.