"A piece of land at Riverside, below the flow of water, was worth 300
dollars an acre. Contiguous to it was another piece not irrigated, which
would not sell for 50 dollars an acre. By bringing water to it, it would
quickly sell for 300 dollars, thus adding 250 dollars to its value. As
the estimate at River side is that one inch of water will irrigate five
acres of Fruit land, five times 250 dollars would be 1,250 dollars per
inch, at which price water for irrigation has actually been sold at
Riverside.
"The standard of measurement of water in Southern California is the
miner's inch under four inches pressure, or the amount that will flow
through an inch-square opening under a pressure of four inches measured
from the surface of the water in the conduit to the centre of the
opening through which it flows. This is nine gallons a minute, or, as it
is figured, 1,728 cubic feet or 12,960 gallons in 24 hours, and 1/50 of
a cubic foot a second. This flow would cover 10 acres about 18 inches
deep in a year; that is, it would give the land the equivalent of 18
inches of rain, distributed exactly when and where it was needed, none
being wasted, and more serviceable than 50 inches of rainfall as it
generally comes. This, with the natural rainfall, is sufficient for
citrous Fruits and for corn and alfalfa, in soil not too sandy, and it
is too much for grapes and all deciduous fruits.
"But irrigation, in order to be successful, must be intelligently
applied. In unskilful hands it may work more damage than benefit. Mr.
Theodore S. Van Dyke, who may always be quoted with confidence, says
that the ground should never he flooded; that water must not touch the
plant or tree, or come near enough to make the soil bake around it; and
that it should be let in in small streams for two or three days, and not
in large streams for a few hours.