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CHAPTER XVIII.

THE MEASUREMENT AND DUTY OF WATER.

G. S. 3472.

Measurement of Water.]

Water sold by the inch by any individual or corporation shall be measured as follows, to-wit: Every inch shall be considered equal to an inch square orifice under a five inch pressure, and a five inch pressure shall be from the top of the orifice of the box put into the banks of the ditch to the surface of the water; said boxes or any slot or aperture through which such water shall be measured shall in all cases be six inches perpendicular, inside measurement, except boxes delivering less than twelve inches, which may be square, with or without slides; all slides for the same shall move horizontally, and not otherwise; and said box put into the banks of ditch shall have a descending grade from the water in ditch of not less than one-eighth of an inch to the foot.

The State Engineer, in his report for 1885, page 52, says in this connection:

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The necessity for a practical standard, or unit, of measure of water is very urgent; one that is simple, positive and adapted to all classes of ditches and canals, and readily understood by all agriculturists, whether small gardener or large farmer. At present we have no unit of measure in universal use throughout the State. All recent legislation regarding irrigation water requires measurements to be expressed in cubic feet per second. This is a correct system, being definite, but the "inch" system is probably more extensively used than any other; and it is astonishing how many ways there are of delivering water under this method, and of estimating its real volume. This unit of measure, known throughout the State as the 'statutory inch,' is defined in section 3472 of the Gen

eral Statutes of Colorado, as follows, viz: 'Every inch shall be considered equal to an inch square orifice under a five-inch pressure, and a five-inch pressure shall be from the top of the orifice of the box put into the banks of the ditch to the surface of the water, said boxes or any slot or aperture through which such water shall be measured shall in all cases be six inches perpendicular, inside measurement, except boxes delivering less than twelve inches, which may be square, with or without slides; all slides for the same shall move horizontally, and not otherwise; and said box put into the banks of ditch shall have a descending grade from the water in ditch of not less than one-eighth of an inch to the foot.' Section 3478 in same chapter makes it a misdemeanor for any person to sell water by the inch, and measure it by any other device than the one described above, with a penalty attached, viz: Upon conviction thereof may be imprisoned not exceeding one year, or fined not exceeding one thousand dollars, at the discretion of the court.' According to this law, where water is sold by the inch, no box can be over six inches perpendicular height. Although the inch method of measuring has been in use since the first irrigation in the State, yet scarcely two people measure it alike, or understand what an inch of water really is; and many a good citizen has inadvertently subjected himself to the penalty of the law. The statutory inch answers very well as a unit of measure for small volumes of water, providing the legal pressure and all other requirements are maintained, but it is quite well understood by irrigators and others, that the legal box can be placed in a ditch, and so manipulated as to deliver quantities of water differing over fifty per cent., either more or less, as suits the interest of the party controlling the box. At the present day, such large quantities are sometimes required to be measured, that the statutory inch is found to be impracticable, as well as inaccurate; for example, in Weld County, a canal company sells ninety-two cubic feet of water per second, delivered in one lateral ditch. If this amount of water was sold by the inch, and measured by a legal box, it would require to be forty-nine feet one inch long, with a height of six inches, and this is impracticable.

"The referees in some of the water districts, in making up their findings, have experienced much difficulty in reducing

to one unit of measure the various statements of water appropriators, and this office has experienced a like difficulty. Most of the statements made in filings were made in perfectly good faith, but the capacities of the ditches were, in many cases, given in inches of cross-section instead of statute inches. For example, a ditch five feet wide by twenty inches deep, would have an area of twelve hundred square inches instead of statute inches, claimed for it, without reference to velocity, or to fall per mile. This was done without any intention to claim more than was due. Many disputes and misunderstandings arise about the exact amount of water due for an 'inch.' To settle the matter, it would be well to have the flow of water through the legal orifice (as specified in existing contracts) defined in specific quantity, in specific time, and, for the future, cubic feet, per second of time, substituted for the inch system, which measures water through boxes of impracticable dimensions, unsuited to the modern practice of irrigation."

The following is the method employed by many of our leading engineers for calculating the capacity of a ditch in cubic feet per second:

Let C represent the cross section of the flowing body of water; P the wet perimeter, or sum of the bottom and side lines of the cross-section; F the fall in a given distance; D the said given distance; X the capacity. Then

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This formula makes no allowance for crookedness of ditch, seepage, evaporation, or other elements that may retard the flow to a greater or less extent, and thus reduce the result; and on the average twenty or twenty-five per cent. should be allowed therefor.

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It seems that the amount of water which may claimed by a ditch appropriation is to be measured by the capacity of the ditch at its smallest point.

Ophir S. M. Co. vs. Carpenter, 6 Nev., 393.
Barnes vs. Sabron, 10 Id. 217.

As regards the efficiency or 'duty,' of water we cannot do better than make the following citation from State Engineer's report, 1885:

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At the present day, it is impossible to define the full duty of water in Colorado, as no trustworthy data can be had, and it is doubtful if this duty can ever be precisely accomplished. There are very many factors of this subject to be considered, such as the nature of the soil, the 'lay' of the land, subsoil, the kind of crop grown, the skill of the irrigator, climatic conditions during the crop season, etc. Although this duty cannot be clearly defined, it is very apparent that in almost every section of Colorado the amount of water used in irrigation can be considerably reduced. Except in a few instances, where necessity has forced the practice of economy, it has not been necessary to restrict the use of water to anywhere near the minimum quantity required to raise a crop.

Powell, in his 'Lands of the Arid Region,' says, one second foot of water will irrigate So to 100 acres in Utah,' but 'many of the farmers will not admit that so great a tract can be cultivated by this unit. In the early history of irrigation in this country the lands were over-supplied with water, but experience has shown that irrigation is most successful when the least amount of water is used necessary to a vigorous growth of the crops; that is, a greater yield is obtained by avoiding both scanty and excessive watering; but the tendency to over-water the lands is corrected only by extended experience.' Colonel Baird Smith, in his report on Italian irrigation, states that 'the general average area irrigated by each cubic foot of water, 'per second,' throughout Lombardy, amounts to 70.2 acres.'

"Probably one of the main causes of the general ignorance of the duty of water is the absence of a definite system of measurement that can be practically applied. In pioneer days the 'miner's inch' was the standard, and an 'inch to the acre' was a common estimate of the duty of water.

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“If the statutory inch be considered equal to 45 cubic inches discharged per second, 38.4 of these inches are equal to one cubic foot per second, and this would be equal to 38.4 acres, per cubic foot, per second, which would be a very low duty. Since the building and operating of large canals on the co-operative system, some attention has been given to the question of the best methods of dividing the waters of a canal, equitably, among shareholders; but this operation had the division only in view, with reference to actual quantity, and the owners of such canals have no direct interest in determining the exact quantity of water required to irrigate a stated The later organized canal companies, which disposed of water in perpetuity, or yearly, by quantity, or by the acre irrigated, have necessarily been compelled to make estimates of the duty of water. These estimates have been based on the experiences of the old irrigators, calculations being made of the discharge of their ditches or dividing boxes, expressed in either statutory inches or cubic feet per second and this quantity compared with the land cultivated for a series of years. On these determinations have been based the first really practical estimates of the duty of water in Colorado, expressed in a tangible form. These estimates range from 50 to 55 acres per cubic foot per second, and this is the generally recognized duty at the present time.

"Many of the canal companies formulate rules and make contracts which are detrimental to the interests of the State, inasmuch as no inducement is held out to the purchasers to use water with economy in irrigation. This is more especially so when water is furnished for a stipulated price per acre, and a maximum quantity agreed upon; also, when the water is sold in perpetuity, with the contract so worded that the benefits derived by the use of less than the maximum named quantity shall inure to the canal company. Contracts for water should be for absolute quantities, and then if the purchaser can farm with less, by skillful and careful use of his water, the value of his surplus, which he might use on other land, or sell to those who need it, will be a premium to strive for. If such contracts were in general use, we might look for a large and rapid increase of the duty of water."

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