File:Preparing land for irrigation and methods of applying water (1904) (14798786853).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

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
so as to present the appearance of low embankments having awide base. In nine cases out of every ten the sides of the levees areleft too steep. The width of the base of a levee, as a rule, should beeight times the height of the crest. Thus a levee 9 inches high shouldhave a base width of 6 feet. The height depends on the difference inelevation of the contour lines and the depth of water to be appliedin one irrigation. With 4-inch contours when completed and settledthe levees are usually 9 inches high. This leaves a margin of safetybetween the surface of water in the check and the top of the levee,providing the depth of water applied does not exceed 6 inches, sincea portion of the water is absorbed bv the drv soil before the check isfilled. CHECK OR SLUICE BOXES. The check or sluice boxes, through which the water is admitted intothe checks, vary in width from 1 foot to 10 feet, They are rectangularboxes passing through the earth embankments, and so arranged that30439—Xo. 145 -04 3 32
Text Appearing After Image:
Fig. 9.—Check box. Section across length at bottom of page, section across side in middle, andlongitudinal section showing floor at top. 33 flashboards can be readily and quickly inserted and withdrawn. Theboxes must be water-tight, inexpensive, and so made and placed asnot to obstruct farm implements. The sketch in figure 9 was made from a medium-sized box which wasdesigned and used by Mr. Joshua Cowell, of Manteca, Cal. Figure 10 shows a cheaper box which is common in StanislausCount). FLOODING CHECKS. Many of the canals in the San Joaquin Valley are operated in a mannerto meet the needs of the check system. Instead of delivering a smallstream for a long period, the practice is to deliver a large volume ofwater for a short period. On land that is checked one man can handle, as a rule, four timesas much water as hecan in flooding fromfield ditches. Un-der this system aflow of 10 cubic feetper second is not un-usual for a -10-acretract of alfalfa; andsince this amountwould cover a f

Note About Images