Principles of Irrigation Engineering – Arid Lands, Water Supply, Storage Works, Dams, Canals, Water Rights and Products

Frederick Haynes Newell

• Publisher: Home Farm Books
• Year: 2021
• ISBN:
  9781528769167
• Topic: Technology & Engineering
• Subtopic: Environmental Management
• Index: Technology & Engineering

"Principles of Irrigation Engineering" is a 1913 work by F. T. Bioletti on the subject of irrigation methods, dealing with canals, dams, storage, water supple, dry land, and related law. Frederic Theodore Bioletti (1865 – 1939) was an English-born American vintner. He studied at the University of California, Berkeley from 1889 to 1900, where he worked with prominent soil scientist Professor E.W. Hilgard. His work with Hilgard on the fermentation of wines under different conditions were significant in helping California vintners to refine their wine production practices and improving the resulting wines. Bioletti was the first chair of the Department of Viticulture and Enology and founded the grape breeding program at the University of California Agricultural Experiment Station. This volume will appeal to those with an interest in irrigation techniques, and their history and development in particular. Many vintage books such as this are becoming increasingly scarce and expensive. It is with this in mind that we are republishing this volume now in an affordable, modern, high-quality edition complete with a specially-commissioned new biography of the author.

PRINCIPLES OF IRRIGATION ENGINEERING.

CHAPTER I

IRRIGATION

Definition.—Under the term “irrigation,” as applied to agriculture, is included all of the operations or practices in artificially applying water to the soil for the production of crops.

Irrigation at the present time, considered from the standpoint of the irrigation engineer, includes the conservation and storage of the water supply, the carrying of water from the source of supply to the irrigable area and distributing it to the lands. It involves, in many cases, the development and bringing to the surface, waters from underground sources, and also the raising of water by pumping or other means to lands which cannot be reached by a gravity flow from the source of supply. Closely related to irrigation is also the question of drainage for the removal of excess waters from the land.

Drainage, either by natural or artificial means, is equally as important as irrigation to insure successful agricultural operations. It is generally impracticable to apply water to lands sufficient to grow crops without a portion of it being wasted either on the surface or underground. This waste, or excess, must be removed either through natural outlets or artificially constructed drainage ditches, in order to prevent the land becoming waterlogged or charged with alkali and rendered unfit for successful farming.

In addition to the physical problems involved in irrigation, economic questions must also be considered. These questions involve estimates on the value of lands to be irrigated and a comparison of these values with the cost of constructing irrigation works in order to determine whether the project is feasible from a financial standpoint.

History and Development.—The practice of irrigation is older than civilization. It originated doubtless in the semi-tropical and relatively arid regions, where there is a periodic overflow of the desert areas traversed by some of the large rivers like the Nile. These streams, coming from plateau or mountain regions, are swollen by seasonal rains or melting of snow. Mankind in the early stages of development learned to guide or assist this overflow by rough dikes and rudely constructed ditches, later building canals to bring the water out to lands which would not be overflowed naturally, and thus gradually becoming independent of the natural rise of the stream. Before historic times the practice of irrigation had been recognized to such an extent that rules relating to the handling of water were embodied in the earliest of known writings. In the code of Hammurabi (2250 B. C.) it appears that provisions were made to cover similar troubles and controversies that are being met to-day. Laws concerning the distribution of water and guarding against waste or damage to a neighbor’s field through carelessness may be copied and applied to modern conditions from the oldest of recorded regulations. In nearly all of the countries bordering the Mediterranean and to the east in Mesopotamia, India and China, the art of irrigation was practised. The early writings on the discovery and conquest of Mexico and of South American countries casually mention the irrigation canals as part of the features of the country.

FIG. 1.—Humid regions of the world, indicated in black; arid or non-productive I regions indicated by uncolored land areas.

The relative location and position of the arid regions of the world are indicated by the black areas on the accompanying diagrammatic map (Fig. 1). This illustrates how small are these humid areas, as compared with the total land surface enclosed within the outlines and left blank as indicating conditions where plant life is dependent largely upon an artificial supply of water or where the climate is too cold for the production of most of the ordinary crops. As indicated on this diagram, the greater part of western Asia and the Mediterranean countries within which civilization has developed are arid or semi-arid; also the greater part of the western half of North America including a considerable portion of Canada, Mexico, and the United States.

In the southwestern portion of the United States, especially in Arizona and New Mexico, remains of irrigation works have been found which were constructed and operated prior to any recorded history of that section. In the valley of the Rio Grande, irrigation was practised by the native inhabitants before the advent of Spanish explorers in the early part of the sixteenth century. The early Spanish missionaries also constructed irrigation works in that valley some time during that century. This, so far as known, was the beginning of modern irrigation in the United States. Some of the works constructed by the early Spanish settlers have been in use almost continuously up to the present time.

In 1847, irrigation was begun by the Mormon settlers in the Salt Lake Valley, Utah. This was the beginning of Anglo-Saxon irrigation in this country. The next irrigation development of any magnitude was about twenty years after work was started in Utah, when it was taken up in Colorado and California. From these parent colonies it gradually spread to the other states of the arid west.

The first attempts at irrigation, as previously stated, were primitive in character and consisted principally in assisting nature in carrying water over the low bottom lands during the flood period. The next step was the diversion of water from the streams and conducting it by means of crudely constructed canals to the lands. The first ditches constructed throughout the west consisted of simple furrows for turning part of the flow of a creek to the low-lying bottom lands. Diversion works, in many cases, consisted of temporary dams of bags of sand placed in the stream to raise the water slightly and divert it to the canals. When not in use, canals were frequently closed by means of an earthen embankment. When water was desired in the canal, the embankment was wholly or in part removed. In the construction of these early canals engineering advice was rarely sought, grades were fixed by the eye or by the flow of water and locations made to conform to the contours of the slopes.

In general it may be said that the advances in irrigation, the oldest of agricultural practices, have been made but slowly. It was not until comparatively recent times that the larger problems pertaining to storage and conservation of water supply were undertaken. Within the past few years remarkable progress has been made in this direction. The ultimate limit of the amount of land which can be brought under irrigation in the arid west depends largely upon the further conservation and storage of water supply and improved methods of transporting, and applying it to the soil.

Needs and Benefits.—The need of irrigation arises from lack of natural rainfall at the times when required by crops. In some regions the total precipitation annually is apparently adequate for all vegetation, but frequently the rain occurs at seasons when it is not needed and fails at critical times, thus irrigation must be practised during the season of summer drought. Under these conditions it may be considered as a form of insurance, while in the truly arid areas it is an absolute necessity.

The benefits which are derived from irrigation are those which arise from the ability to supply the amount of water needed by the growing plants in the quantity and at the times when it is most beneficial in crop production. In the arid or dry regions where rainfall is irregular or spasmodic there are consequently few clouds, the sunshine reaches the soil without obstruction and where water can be supplied this continuous unobstructed daily sunshine stimulates plant growth to a high degree, because of the well-known fact that all life and growth on the earth is maintained by the sun’s energy.

Irrigation affords ideal conditions for agriculture, since with the life-giving sunlight and a means to supply moisture at proper times and in the exact quantity needed, agriculture can be reduced more nearly to scientific accuracy.

It is largely because of these facts that agriculture in an arid region offers larger opportunities for returns from a given area than in the humid regions, where dependence must be placed upon an erratic rainfall. The amount of sunlight in the humid areas and consequently the forces leading to growth are limited by the many cloudy days. Ignoring this fact, it has sometimes been urged that the same amount of energy and investment put in the agricultural operations of the eastern part of the United States should be equally or more productive than in the western, but, in this statement, there is a neglect of consideration of this all-important item of total amount of sunlight.

PLATE I

FIG. A.—Diverting dam in Boise River, Idaho, a typical structure for taking out river water by gravity.

FIG. B.—Main northside canal of Minidoka Project, Idaho. Illustrative of the larger irrigation canals, with power transmission lines located on the bank.

FIG. C.—Water being distributed to the fields through furrows after having been diverted from the river by gravity canals.

FIG. D.—Water being applied to the fields by flooding.

Methods of Irrigation.—Ordinarily, water for irrigation purposes is conducted from some stream or lake by means of open canals dug in the rocks or earth, similar in many respects to the drainage ditches commonly used in humid regions. In fact, the resemblance between the irrigation canal and a drainage ditch is so great that the word “ditch” is commonly applied to the small irrigating canal, although it is preferable to limit the word “ditch” to its original application in drainage.

The main canal, designated to bring water to a given area, heads usually in some perennial stream and takes water from it either by means of a dam or obstruction in the river, forcing some of the water into the canal (see Plate I, Fig. A) or the water is diverted by building the inlet gates at a level sufficiently low to permit it to flow from the stream into the head of the canal. From this point the canal is built on a gently descending grade less than that of the stream from which a supply is derived, that is to say, if the stream falls at a rate of 10 ft. per mile, the irrigating canal may be built with a fall say 1 ft. per mile and at the end of 10 miles the canal will be 90 ft. above the bed of the stream. To build such a canal in ground which will sustain it, the canal after bordering the stream for a short distance must turn from it, skirting the valley and thus partly surrounding a considerable body of land which becomes wider and wider between the canal and the river. Water released from the canal will flow down the natural drainage lines back to the river, or it can be kept up on the higher ridges and thus brought to the highest points of most of the farms between it and the river.

The canal divides or sends off branches and these again send from their sides other smaller branches, sometimes called laterals, dividing and the sub-dividing until each farm is reached. (See Plate I, Figs. C and D.)

Earthen canals necessarily lose a considerable amount of water by percolation or seepage into the soil, especially if this is sandy or gravelly. There are also small losses by evaporation from the surface. Where water is very valuable the loss by percolation is frequently reduced by lining the canals with masonry or other impervious materials, or by confining the water in pipes as is the case of city supply.

Water having been brought to the area to be irrigated, there are a variety of ways in which it is applied to the land. One of the common methods, ordinarily known as “flooding,” is to deliver the water to the highest portion of the land and allow it to flow downward over the slope until the entire area or field to be irrigated has been covered. (Plate I, Fig. D.) Another method, sometimes called the “check system,” requires that the land be divided into small areas, each surrounded by a check or border of earth a few inches in height. Water is turned into each of the small areas until it is covered to the required depth. This method has advantages over ordinary flooding in that the amount of water applied to each portion of the land can be more accurately controlled. In the “furrow system,” water is carried over the land in small furrows (Plate I, Fig. C), excavated by means of a plow or other suitable appliance, a few feet apart over the entire area. Still another method, known as “sub-irrigation,” consists in bringing the water below the surface by means of pipes laid in the soil and allowing it to escape through small openings in the walls of the pipes. This method, while theoretically nearly perfect, is ordinarily prevented by the excessive cost.

Comparison of Irrigated and Non-irrigated Lands.—The advantages of irrigation are best expressed in values of crops per acre on irrigated and non-irrigated areas. Unfortunately it is difficult to make a comparison of this kind on account of the lack of comparable data relative to crop values in different sections of the country. There are examples where special crops grown without irrigation have yielded greater returns per acre then other crops grown with irrigation. There are few if any examples, however, where non-irrigated orchards...

Table of contents

• Cover
• Title
• Copyright
• Preface
• Contents
• List of Plates
• Chapter I: Irrigation
• Chapter II: Irrigable Lands
• Chapter III: Water Supply
• Chapter IV: Design and Construction of Canals
• Chapter V: Canal Structures
• Chapter VI: Distribution Systems
• Chapter VII: Irrigation by Pumping
• Chapter VIII: Drainage
• Chapter IX: Operation and Maintenance
• Chapter X: Storage Works
• Chapter XI: Reservoir Sites
• Chapter XII: Dam Sites
• Chapter XIII: Timber Dams
• Chapter XIV: Earth Dams
• Chapter XV: Rock-fill Dams
• Chapter XVI: Masonry Dams
• Chapter XVII: Outlet Works
• Chapter XVIII: Water Rights
• Chapter XIX: Economic Features of Irrigation
• Index