134 



THE APPLE 



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'RON PL/JTE 



under a 4-inch pressure head as it passes through. A section of 

 the hydrant box, showing the adjustable steel slides to regulate 

 the opening, is given in Fig. 56. 



On the Gage Canal system in Riverside County, California, the 

 water supply for the tiers of 40-acre tracts is taken from the canal 

 in riveted steel pipes, which are from 6 to 10 inches in diameter. 

 These larger mains are connected with 4-, 5-, and 6-inch lateral 

 pipes of the same material, which convey the water to the highest 

 point of each 10-acre tract. This general arrangement is shown 

 in Fig. 57. 



The ditches conducting water from gravity canals to orchard 

 tracts do not differ from the supply ditches for other crops. 



Location of the 

 trees. In setting 

 out any orchards 

 which are to be 

 irrigated, the ele- 

 vation of the sur- 

 face of the land 

 ought first to be 

 ascertained. This 

 is usually done 

 by making a contour survey, which divides each tract by level 

 lines into a number of curved strips or belts. With these lines 

 as a guide the proper direction for the tree rows can readily be 

 determined. Where the trees are watered in basins or checks, 

 fiat slopes are not so objectionable, but in furrow irrigation a slope 

 of about 2 inches to 100 feet is necessary to insure an even dis- 

 tribution of water. When streams are to be run in the furrows, 

 the slope of the furrows may be increased to 8 or 10 or even 

 12 inches to 100 feet. On slopes varying from 10 to 40 feet to 

 the mile, therefore, the tree rows may be located, at the proper 

 distance apart, down the steepest slope. Under such conditions 

 the trees are commonly planted in squares. 



Where the slope is so steep that difficulties are likely to be 

 encountered in distributing water, the equilateral, hexagonal, or 

 septuple method of planting (as it is variously termed) should be 

 adopted. In this method the ground is divided into equilateral 



Fig. 56. Section of hydrant box, showing device of meas- 

 uring miner's inches. (Riverside Water Company) 



