A large part of the watering in the arid States is from mountain streams or from reservoirs filled from such streams or from melted snows. But in the States east of the mountains the streams usually run in deep channels and orchards are usually on much higher land. In the prairie States they could rarely be used for direct irrigation, as the channels are low and they usually run dry except in wet seasons in August, when most needed. But in the more uneven or hilly sections of the States east of the lakes a combination of neighbors will often permit taking the water from some point higher up on the stream into irrigating channels for watering fruits on a lower level. But the rule that water must be pumped from streams, stream-beds, or wells on lower levels to reservoirs on the highest side of the orchard or small fruit plantation has few exceptions.
Perhaps no plan for general uses is more practical and profitable than the one extensively used in east Europe and over a large part of central Asia, where they usually have rains in the early part of the season. During the spring months water is pumped by windmills from a lower level to reservoirs on the highest side of the fruit plantations. These reservoirs are excavated in the soil and the bottom and sides are puddled with clay as now practised in Kansas and Nebraska. When made an iron pipe is laid from the bottom to a distributing pipe across the high side of the plantations, with a hydrant for every two rows of trees or for a space of about forty feet for small fruits and gardens. The water is led by a hose to wooden troughs made V-shaped for running it over the ground. In orchard-watering some work is done in advance. The earth is drawn away to a depth of four or five inches around the crown of every tree, forming a basin six to eight feet in diameter, with the loose dirt compacted at the edges. About four inches of sand is covered over the bottom of the cavity to prevent baking when water is applied and to lessen the evaporation. The V-shaped troughs are made long enough to reach from one tree to another and are set one at a time on small iron supports made for the purpose. The water runs into a cavity until it is filled, when another is added to reach the next tree. Enough of the troughs are needed for one row. In watering the next row the troughs are brought over one at a time as wanted. In the East the spaces between the excavations are covered with some leguminous cover-crop, usually the sandy vetch. In a very dry time the water is permitted to run after the excavations are filled for a few minutes at each tree. After the inexpensive plant is established, the cost of watering each tree twice during the season - when the fruit is less than half grown and again when two thirds grown - was estimated by a number of orchardists at eight cents. In the arid States this kind of watering would do little good. But to bridge over a dry period in the humid States, it secures a good crop of perfect fruit, when the unwatered trees prove nearly a failure. Even in Florida, with an average rainfall of over sixty inches, irrigation has been largely practised in orange orchards, to bridge over the dry periods and also to save the garden crops and tobacco. In this case the water is pumped from wells by gasoline pumps into large cypress tanks, from which it is distributed over the comparatively level surface by iron pipes to which hose is attached.
In Illinois, Wisconsin, Iowa, and other drift-soil States of the West, the subsoil favors the economical use of water with after culture to prevent the soil from baking.
Another consideration in the prairie States, and indeed east to the Atlantic and south to the Gulf, is that no disputed rights are to be considered or feared, such as continually harass users of water in the arid States.
As an illustration of the possibilities of reservoir irrigation, the plant of Mueller Brothers, near St. Joseph, Missouri, may be mentioned. The water is pumped from a well on a lower level by a gasoline-engine to a large reservoir on the bluff, nearly one hundred feet above the land to be irrigated. This gives a force to the water convenient for washing vegetables, and certain home uses at the house and barn, whence it is carried to quite an extensive vegetable garden and small fruit plantations. During the dry season of 1901 grocers and hotel-keepers sought the Mueller vegetables and fruits at advanced prices.
The cost of running the pump at this quite extensive plant averages about thirty-five cents per day, but the water is elevated to an unusual height. An elevation of the bottom of the reservoir of ten feet above the land to be irrigated answers the purpose about as well, as the water will run freely to all parts below that level. In the arid States the surfaces to be watered are levelled often at great expense, but this is usually quite impracticable in the prairie States or east or south of the lakes, and it is not needed, as the water is taken from point to point in wooden troughs or in iron pipes and is distributed by hose.