VARIANT 1. Historical Background: Developments in Water Supply Systems

Water is power not only in the hydraulic sense, but in relation to progress and culture; campaigns as well as fortresses have been lost, projects rendered impracticable and communities have flourished or decayed for want of water.

Water was an important factor in the location of the earliest settled communities, and the evolution of public (and later industrial) water supply systems is tied directly to the growth of cities. There is much archaeological evidence to indicate that ancient peoples were concerned with their water supply. In the development of water resources beyond their natural condition in rivers, lakes, and springs, the digging of shallow wells was probably the earliest innovation. Wells were sufficient for small communities, and rivers provided enough water for civilizations along the Tigris and Euphrates, the Nile, and the Indus rivers.

But populations grew, the need for water increased, tools were developed, wells had to be dug deeper, and water had to be brought in from more distant sources. These ancient systems included storage reservoirs at water sources, canals and aqueducts for water conveyance to points of use, and water-distribution systems.

Highly advanced systems appeared about 2500 BC and reached their peak in the system supplying ancient Rome. Brick-lined wells were built by city dwellers in the Indus River basin as early as 2500 BC, and wells more than 1,600 feet (almost 500 metres) deep are known to have been used in ancient China. Construction of qanats, slightly sloping tunnels driven into hillside that contain groundwater, probably originated in northwestern Persia (now Armenia) about 700 BC. From the hillsides the water was conveyed by gravity in open channels to nearby towns or cities. The use of qanats became widespread throughout the region, and some are still in existence. Until 1933 the Iranian capital city, Tehran, drew its entire water supply from a system of qanats.

The need to channel water supplies from distant sources was an outcome of the growth of urban communities. Among the most notable of ancient water conveyance systems are the aqueducts built between 312 BC and AD 455 throughout the Roman Empire. Some of these impressive works are still in existence. The writings of Sextus Julius Frontinus (who was appointed superintendent of Roman aqueducts in AD 97) provide information about the design and construction of this system. The outstanding features of the system were 11 major aqueducts totalling 359 miles (578 kilometres) in length – of which 30 miles were supported on stone arches – that delivered some 50,000,000 gallons (189,000,000 litres) of water to the city daily and supplied Rome itself.

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qanat [kə'na:t] (in the Middle East) is a gently sloping underground channel or tunnel constructed to lead water from the interior of a hill to a village below

impracticable неосуществимый

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