The New Student's Reference Work/Irrigation
Ir′riga′tion is the artificial application of water to land. Ruins of basins, acqueducts and canals give ample evidence of its extensive use in pre-historic times. Irrigation was practiced among the Assyrians, Babylonians and Phoenicians and China, Egypt and India are noted for the antiquity and the completeness of their systems. Remains of works in Colorado, Utah, New Mexico and Arizona show that the pre-historic inhabitants practiced irrigation and some of their ditches are used in present operations. The Mormons furnished the United States with the first irrigation on a practical scale. In California it was developed in connection with mining. The Union Colony established in Colorado in 1870 made the Greeley District famous for its productions, especially potatoes and alfalfa.
The Spaniards who invaded the country learned irrigation and carried it to their kinsmen in Mexico. In southern California the early missions surrounded their stations with farms made fruitful by watering the parched plains. The wonderful results of these later-day ventures induced the adoption of systems of irrigation in other portions of the regions of insufficient rainfall, and this was largely done by forming colonies, their settlers locating on small, near-by farms and obtaining water from a common source. In this manner increasing areas were brought under cultivation, and such colonies, with individuals, associations and companies, introduced irrigation in many localities. In the 80s millions of money was put into such projects speculatively, but few proved profitable for investors, although they were the means of substantial advancement in extension of irrigation.
Government Reclamation Projects. The whole scheme, however, has become so vast and of such economic importance that state and national governments are more and more assuming its responsibilities. The reclamation act, which became a law in 1902 marked the beginning of a new era in irrigation in America. This provides that the proceeds from the sales of public lands in 13 states and three territories be used in constructing irrigation systems therein. Any lands thus reclaimed are subject to entry only under the provisions of the homestead laws in tracts of not less than 10 nor more than 160 acres, and between these limits the acreage may be restricted by the Secretary of the Interior as his judgment dictates. The settlers are required to pay, in not to exceed ten yearly installments, such amounts per acre as may be equitably apportioned—which in the case of the initial system put in operation was $26—with a view to returning to the reclamation fund the estimated cost of the construction of the projects, which in effect gives free land under the homestead laws and permanent irrigation systems and water at cost, although the title to the sources of supply remains in the government until otherwise provided by Congress. When the payments are made for the major portion of the lands irrigated, the control of the works passes to the owners of the land, to be maintained at their expense under such form of organization and under such rules and regulations as may be acceptable to the Secretary of the Interior. Under this act much work is being accomplished and stupendous schemes undertaken. Extensive engineering projects are under way in several of the states and territories affected by this act, which applies to Arizona, California, Colorado, Idaho, Kansas, Montana, Nebraska, Nevada, New Mexico, North Dakota, Oklahoma, Oregon, South Dakota, Utah, Washington and Wyoming. The projects already authorized contemplate the ultimate redemption of 2,000,000 acres.
In 1913 water was available from the Government irrigation systems for 1,290,107 acres, and 942,272 acres were under contract to receive water. Conservative engineers estimate that there are 30,000,000 acres of our desert which may be reclaimed.
The Salt River project in Arizona is one of the best known of the Government irrigation projects. Its principal structure is the Roosevelt dam, 280 feet high and 1,125 feet long on top. The storage capacity of the reservoir created by this dam is 1,284,000 acre-feet, or sufficient to cover 1,284,000 acres one foot deep. It supplies water to about 190,000 acres of land in the vicinity of Phoenix, and power created at the dam site is transmitted electrically about 100 miles down the valley to pump water to additional areas.
Gunnison Tunnel, a six-mile bore through the Vernal Mesa in Colorado; Shoshone dam, 328 feet high, in northern Wyoming; and Laguna dam, a weir nearly a mile long across the Colorado River 12 miles above Yuma, Arizona, are other notable engineering works of the Service. A unique pumping project has been built in western North Dakota, where the pumps are placed on floating barges which accommodate themselves to changes in the river banks and in the water level. The pumps force water through pipes with flexible joints to settling basins on the shore. Power is generated with lignite mined from a Government coal mine in the vicinity.
Two of the largest structures erected by the Reclamation Service are under construction at the present time, the Elephant Butte dam near Engle, New Mexico, and the Arrowrock Dam in southern Idaho. The Elephant Butte Dam will be 290 feet high and 1,200 feet long on top. The reservoir created by this dam will have a superficial area of 40,080 acres, and a capacity of 2,627,700 acre-feet. It will serve a double purpose in protecting the lower valley from destructive floods and insuring an ample water supply for 180,000 acres of land in New Mexico, Texas and Mexico. The Arrowrock dam in Boise River canyon will be 350 feet high, and its cubical contents will be about 500,000 cubic yards. Its purpose is to store the flood and excess waters for the irrigation of about 200,000 acres of land in the vicinity of Boise.
A brief summary of the work of the Service shows that it has built 7,961 miles of canals and ditches, 401,000 feet of flumes, 120,000 feet of culverts, and 831,000 feet of pipe lines; its excavations amount to more than 99,000,000 cubic yards; it has built 697 miles of wagon roads and 51 miles of railroad, and has in operation 2,331 miles of telephone lines; it has developed 32,466 horsepower, and built 351 miles of electric transmission lines. Its tunnels have a length of over 22 miles, its canal structures number 50,233, and it has built 3,339 bridges, and 82 miles of dikes. The capacity of its reservoirs amount to 5,051,210 acre-feet.
As a result of this work it is estimated that 100,000 people are already established in homes on the Government projects. Flowing out of the engineering activities are countless beneficial factors which are tending to eliminate isolation, to promote betterment of social and educational conditions, and to dignify agriculture as a profession. Centralized graded schools, trolley lines in the farming sections, country clubs and assembly halls, churches and organizations for producing and marketing products, co-operative creameries, canneries, laundries, etc., are among the numerous agencies being developed to make rural life attractive and complete.
The government aid is not intended to discourage or interfere with a continuance of private enterprise, and the government is supposed to enter only fields where private capital is not strong enough to develop the opportunities properly or where, if left to individuals, the possibilities would be only partly utilized.
Engineering skill has performed wonders in irrigation construction; great dams and reservoirs have been built, mountains tunneled, canyons spanned depressions bridged, rivers diverted, and waters conducted in devious ways for long distances and by these means and by canals been made available to the land. Naturally irrigation has been most associated with arid regions; but when pursued in many of the more humid sections, results have been obtained that proclaim its widespread beneficence.
Storage Reservoirs. The storage reservoir has come to be an essential part of irrigation schemes, and water for this purpose is mostly obtained from streams having their sources in the forests and melting snows of the mountains. In the springtime and early summer these streams are converted into swollen torrents, and in the earlier years their waters hurried to the oceans, unused, but they are being more and more diverted and stored to reclaim the dry lands. The early systems depended mostly upon the natural flow of the streams for water-supply, diverted by dams and canals, but in the growing season the streams were lowest, and, when water was most needed, it often was not available. This condition resulted in the extensive building of dams and storage reservoirs, in which are collected the flood-waters, thus not only insuring a supply when most needed but making possible the reclamation of vast additional areas hitherto accounted worthless. From these artificial lakes and reservoirs the waters are conducted into main canals and thence through lateral channels to the farms. A feature of the great enterprises undertaken by the government is the erection of works to collect and store these immeasurable flood-waters, making them available for distribution as needed. At the time of the passage of the reclamation act, however, irrigation systems had already been built along nearly every stream in the arid states, and works of considerable magnitude constructed for the storage of floods and the diversion of rivers, irrigating in the aggregate over 7,500,000 acres.
It is estimated that 90 per cent. or more of the irrigated land in the United States is supplied, mostly by gravity, with water front surface streams. The application of water is mostly done by flooding, by furrows and by subirrigation, and for best results skill and judgment are required as to how, when and in what quantities it should be used, which is governed largely by the quality of the soil and the kind of crops raised.
California leads in the number of irrigators and the value of produce from irrigated land, although Colorado has the greatest irrigated area. Of the annual productions on the irrigated farms of the United States forage-crops constitute over one third of the total. Fruits and vegetables are important items, largely grown in favoring localities for winter marketing. The benefits of irrigation are seen in such yields as ten tons per acre of alfalfa per season, five tons of clovers and timothy or the 400 to 500 bushels of Irish potatoes per acre, with the element of uncertainty as to moisture supply practically eliminated. Unless, however, scientific cultivation is given, the best results are not obtained, which applies equally where irrigation is not practiced; and after a field has been watered, following proper cultivation, the top soil should be stirred to aerate the ground and provide a loose, finely pulverized surface, by which excessive evaporation is prevented.
Dry Farming. In this the same principles are involved as in the so-called dry farming so widely exploited in recent years; but these principles are as old as they are excellent and simply mean good tillage, the mode of procedure depending on the requirements of the soils, seasons, climates and crops. It contemplates cultivation of the ground in such manner and at such intervals as will best improve its physical condition and prepare it for the reception and retention of the natural precipitation. By maintaining the surface soil in a proper condition capillary attraction with the moisture beneath is broken, lessening the loss of water — in short such methods of tillage as best promote rapid percolation into and prevent evaporation out of the soil. The conclusions from experiments made in Utah by the United States government are that “under such conditions, with a rainfall averaging 12 inches per annum, dry farming is feasible,” although it is claimed that good results have not been infrequent where the precipitation has been even less. Its value is manifest and important to the husbandmen of the semiarid region where irrigation is impracticable or impossible, as with the natural rainfall profitable yields are obtained that otherwise have been impossible, and its increasing adoption is proving most beneficial. Its general principles mean much to every farming community, but are vital to the agriculture of regions deficient in rainfall.
The following table shows the areas of the Government irrigation projects and the expenditures to December 31, 1913:
| Expenditures |
|New Mexico-Texas||Rio Grande||156,000||2,850,000|
|North Dakota||N. Dak. Pumping||26,182||927,000|
|South Dakota||Belle Fourche||100,000||3,192,800|
During the early history of irrigation, farmers naturally confined their efforts mainly to diverting small streams in small valleys if the slope of the country and the topography were such as to make the work easy and cheap. With the values of land then existing no expensive developments were practicable.
The accumulation of alkali on the surface of irrigated lands, which was at first thought a serious detriment, is remedied by underdrainage, and, strange as it may seem to the uninformed, tile drainage appears likely to become not uncommon in many irrigated districts. In fact, irrigation and drainage go hand in hand, and most of the government's irrigation projects provide for elaborate drainage systems. It is anticipated that the advocates of national drainage works for the reclamation of the vast swampland areas of the United States will look to Congress and the Reclamation Bureau to extend the service to include the reclamation of these areas.
In the arid regions there are yet millions of acres that lack only water to make them productive, already possessing, as they do, the other elements of fruitfulness. In the United States prior to 1870 probably less than 20,000 acres were irrigated; by 1880 the area was probably 50 times greater; and the 13th census showed that in 1909 there were 13,738,485 acres irrigated, representing 158,713 farms, producing crops valued at nearly $181,617,396 of which more than $175,907,232 was credited to the irrigated fields of the 11 arid states of Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming.The various governmental projects for storing the flood-waters instituted since then, together with the numerous private enterprises, including the improvement, enlargement and extension of canals and better administration of the water supply, promise to make productive wide areas heretofore barren.
- Rio Grande 25,000 acres additional in Mexico.
- Yakima: Sunnyside Unit 100,000 acres: Tieton Unit 34,000 acres.