Scene below an irrigation reservoir near Richfield, Idaho, showing a field irrigated by means of canals and ditches.
We can, then, hold or conserve the water, first, by leaving the steeper slopes covered with vegetation; second, by keeping the soil loose; and, third, by building reservoirs to hold the floods. We can make use of the conserved water by carrying it in pipes or ditches to those regions where it is needed. We can get rid of too much water by draining the swamps, and building dikes to protect lowlands from river floods.
Let us now learn something of the different uses of water. Every one of our homes has its water supply. In the city the water comes through pipes from some distant reservoir. In the country the homes are so far apart that it is difficult to supply them in this way. The water in the streams is often not suitable for drinking, and if there are no springs near by it has to be obtained by some other means. Nearly everywhere in the earth under our feet water can be found by digging or boring a well. Sometimes we have to go only a few feet, at other times many hundreds of feet. This water in the earth, or ground water, is of very great importance. It enables us to build our homes where we wish. Spring water is that which finds its way to the surface through some tiny crack or fissure in the rocks. How delicious is the pure, cold water that comes out of the shady hollow in the hills! You can form in your minds a picture of the rain falling on some distant mountain, of its soaking into the ground and finally reaching the little crevices in the rocks. Along these crevices it may have crept for days and perhaps years until at last it found an outlet in some spring.
The great river flows by so quietly that we often forget in how many ways it is serving us. It serves not only those upon its banks but those who live hundreds of miles away and who, perhaps, have never seen it. It was the first and easiest means of travel used by our forefathers before there were any roads or railroads through the wilderness. It now aids in carrying on trade between different regions. If large and deep enough, it permits boats from all parts of the world to reach the very heart of our country.
Canals might be called artificial rivers. They serve an important purpose in nearly level countries where Nature has placed no navigable river. Although canal boats usually move slowly, yet they can carry goods cheaper than railroads can. The Erie Canal, in connection with the Great Lakes and the Hudson River, makes it possible for us to go all the way by water from the heart of the continent to New York City. The Erie Canal has helped make New York City the greatest city in our country. The canal across the Isthmus of Panama saves ships a journey of many thousand miles around South America.
Rivers serve us in yet another way by affording water for irrigation. A great river like the Colorado flows through regions of many different climates. Some rivers become so small in the summer that it is necessary to build great reservoirs at their headwaters in order to insure a supply when the crops need it. But in the case of the Colorado this is not necessary. The headwaters of this river are among lofty mountains, where the melting snows and summer showers make the waters of the river higher in the early summer than at any other season of the year. Thus its great delta, the Colorado Desert, has become the home of many thousands of people.
Another use which we make of rivers is by putting the water to turning mill wheels. If you will turn to your geographies, you will find that nearly all the great manufacturing cities of our country have grown up around rapids or waterfalls, where some river tumbles over a ledge of rocks.
Once we had to build our mills close to the rivers to use the water power, but this is no longer necessary. Now we build electric-power plants by the rivers and carry electric energy more than a hundred miles to any place where we wish to use it. Electricity made from the distant mountain waterfall will do any kind of work for us wherever we carry it. Thus we see that the river works for us in more than one way. After it has created power for our factories, it can be turned on to the thirsty fields, where it will serve us equally well.
Great Western Power Company of California