Ralph Rose, age 13, of Carson City, Nev., for his question:
WHEN WAS WATERPOWER FIRST USED?
Waterpower is power derived from the fall of water from a higher to a lower level and extracted by means of waterwheels or hydraulic turbines. The use of waterpower dates from ancient Greece and Rome, where waterwheels were used for the milling of corn.
The availability of cheap slave and animal labor during ancient times restricted the widespread application of water power until about the 12th century. During the Middle Ages, large wooden waterwheels were developed with a maximum power output of about 50 horsepower.
Modern waterpower owes its development to the British civil engineer John Smeaton who in the late 1700s built the first large waterwheels using cast iron construction.
Waterpower played an important part in the development of early American towns. Starting with the gristmill and the sawmill of colonial times, waterpower gave impetus to the growth of the textile, leather and machine shops industries in the early part of the 19th century.
Although the steam engine had already been developed at this time, coal was scarce and wood unsatisfactory as a fuel, Waterpower helped to develop the early industrial cities until the canals to the Midest were opened along the so called fall line, where the upland mountain region meets the coastal plain.
Combining the advantages of available waterpower with location at the upstream end of river navigation, the earliest waterworks that led to the growth of cities in the Northeast were located at what are now Pawtucket, R.I., Paterson, N. J. and Fall River, Mass.
The Mississippi River fall line at Saint Anthony Falls is largely responsible for the development of Minneapolis, Minn., as a grain milling center.
Early American waterpower works were limited to drops of about 17 feet and dams and canals were necessary for the installation of successive waterwheels where the drop was greater.
Replacement of nearly all waterwheels by steam came about when coal became readily available.
The rebirth of waterpower had to await the development of the electric generator, further improvement of the hydraulic turbine and the growing demand for electricity by the turn of the 20th century.
Commercial power companies began to install a large number of small hydroelectric plants in the mountain regions near the major population centers, and by 1920 hydroelectric plants accounted for 40 percent of the electric power produced in the United States.
Hydroelectric power generation was accelerated by the establishment of the Federal Power Commission in 1920. Although additional hydroelectric plants were being built, the simultaneous development of larger and more efficient stream power plants made it obvious that only very large and costly hydroelectric installations could compete effectively, and that the federal government would have to pay a major share of their construction.
The Tennessee Valley Authority, or TVA, started government participation in large scale waterpower development. Since its establishment in 1933, the TVA has been very successful.