What is the use of all this work? Why not wait for the rains to come and wet the earth, as the farmer does in the eastern United States? The Mexicans, who have tilled these valleys for more than two hundred years, ought certainly to have learned in all that time how to get the best returns. You may be sure that they would not water the ground in this way if it were not necessary. The fact is that over a large portion of the western half of the United States it does not rain enough to enable the farmer to grow his crops. The climate is generally very different from that of the Middle and Eastern States.
When the Mexicans moved northward into the valley of the Rio Grande River, into Arizona and California, they found a climate similar in many respects to that at home, and soon learned that it was necessary to water the land artificially in order to make it productive. Though in many places sufficient rain fell, yet the heaviest rainfall came in the late summer or winter, when the plants needed it less, while the spring and summer were long and dry. The Mexicans were not the first to practise watering the land, if we may judge from the ruins of ancient ditches constructed by the primitive Indian inhabitants. It is evident that they too made use of water in this manner for the growing of their corn and squashes.
This turning of water upon the land to make it productive is termed "irrigation." The work is performed in different ways, as we shall see later. Irrigation is now carried on through all portions of the United States where the rainfall is light and streams of water are available.
To one who has lived in a country where there is plenty of rain, it seems to involve a great deal of work to prepare the land and to conduct water to it. One may feel pity for the farmer who has to support himself in this manner in so barren a country. I am sure, however, that if any such person will stop to think, he will remember times when in his own fertile home the expected rain did not come, and the vegetation wilted and dried up. He may have become discouraged because of a number of "dry years," but probably never thought that he had the means at hand to make up, at least in part, for the shortcomings of Nature, in sending too much rain one year, and another year too little.
FIG. 113.—WATER-WHEEL FOR LIFTING WATER FOR IRRIGATION, VIRGIN RIVER, SOUTHERN UTAH
It would doubtless have paid such a farmer many fold to have been prepared at the coming of a dry year to turn the water from a neighboring stream over his lands. This process would have involved a good deal of labor; but how the plants would have rejoiced, and how abundantly they would have repaid him for the extra trouble!
The showers come without regard to the time when growing things need them most, but with irrigation the crops are independent of the weather. The farmer may be sure that, if he prepares the ground properly and sows the seed, the returns will be all that he can wish. In many localities several crops may be raised in a year by this method where otherwise only one would grow.
Now let us see how the water is taken from the streams and what are the different methods employed to distribute it over the land. Almost every valley is traversed by a stream, great or small. It may be a river, with a large volume of water, or a creek which completely dries up during the long, rainless summers of the West.
