File:Preparing land for irrigation and methods of applying water (1904) (14755904846).jpg

Identifier: preparinglandfor145unit (find matches)
Title: Preparing land for irrigation and methods of applying water
Year: 1904 (1900s)
Authors: United States. Bureau of Irrigation Investigations United States. Office of Experiment Stations
Subjects: Irrigation farming West (U S )
Publisher: Washington : U.S. G.P.O.
Contributing Library: U.S. Department of Agriculture, National Agricultural Library
Digitizing Sponsor: U.S. Department of Agriculture, National Agricultural Library

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>75r>-- / >fee/ shoe 4 x <? Seciio/7 on A B r~2— ho/e c 2 /ron hook, Make 8(4 for each end) Fig. 3.—Homemade land grader. On the largerranges of the Statefield ditches or lat-erals are frequentlylaid out by means of the engineers level. TThen the slope of attO-acre field does not exceed 80 feet to the mile, the level is set upin a position to command the upper half. The front chainman carriesa leveling rod and the rear chainman a long-handled shovel. Some-times the chain is dispensed with and the distances are ascertained bypacing. A beginning is made by holding the rod on the surface of the ground 26 at the highest corner of the field and next to the supply ditch. Thetarget is then read and raised, say 0.3 of a foot, and the front chain-man stretches the chain or tape to its full length of 100 feet andendeavors to lind a spot of the right elevation to suit the rod reading.While the reading is being taken and the target again shifted 0.3 foot
Text Appearing After Image:
/J Shaft Fig. 4.—Leveler. higher the rear cnamman makes a mark in the soil with his shovel.The driver of the ditch plow follows the rear chainman, keeping atleast 200 feet in the rear of the latter, and, being seated on a sulky, hecan look ahead and improve on the grade location marked out by curv-ing the ditch in order to have fewer sharp bends. 27 A grade of 0.25 per 100 is ample for fields that are carefully leveled,but if there are surface irregularities it is well to increase the gradeto 0.3, or even 0.4, per 100. The homemade level shown in figure 5 is pretty generally usedthroughout the Gallatin Valley to locate ditches and laterals. It iscarried by one man, and an assistant makes marks, as in the formercase, with a shovelto guide the driverof the ditcher whichfollows him. Theusual grades allowedare from J to f ofan inch to the rod. In the majority of cases no instruments are used to locate fieldditches. The proprietor of an irrigated farm becomes in time famil-iar with the s

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