THE IRRIGATION AGE. 



555 



Head Flumes. 



Formerly head flumes for orchards were built of wood, 

 but the steady increase in the price of lumber and the 

 decrease in the price of Portland cement have induced 

 many fruit growers to use cement instead. When built 

 of wood, the length of the sections varies from 12 to 20 

 feet, 16 feet being the most common. The bottom width 

 runs from 6 to 13 inches, while the depth is usually 1 

 to 2. inches less. Redwood lumber 1J4 inches thick is 

 perhaps the best for the bottom and sides, and joists of 

 2 by 4-inch pipe or fir are commonly used for yokes 

 which are spaced 4 feet centers. Midway between the 

 yokes auger holes are bored and the flow through these 

 openings is controlled in the manner shown in figures 



11 and 12. A 2-inch 

 fall for each hun- 

 dred feet may be re- 

 garded as a suitable 

 grade for head 

 flumes, but it often 

 happens that the 

 slope of the land is 

 much greater than 

 this, in which case 

 low checks are 

 placed in the bot- 

 Fig. 9. Wooden Box Placed in Bank of Headfom of the flume at 



each opening, a s 

 shown in figure 12. 



A head flume composed of cement, sand, and gravel 

 costs as a rule about twice as much as a wooden flume 

 of the same capacity, but the early decay of wood, espec- 

 ially if it comes in contact with earth, makes the cement 

 flume cheaper in the end. By means of a specially de- 

 signed machine, which is patented, cement mortar com- 

 posed of one part cement to about six parts of coarse 

 sand is fed into a hopper and forced by lever pressure 

 into a set of guide plates of the form of the flume. Such 

 flumes are made in place in one continuous line across the 

 upper margin of the orchard tract. After the flume is 

 built and before the mortar has become hard, small tubes 

 from 24 to iy 2 inches in diameter, the size depending 

 somewhat on the size of the flume, are inserted in the 

 side next the orchard. The flow through these tubes is 

 regulated by zinc slides shown in figure 12. Flumes of 

 this kind are made in five sizes, the smallest being 6 inches 

 on the bottom in the clear and the largest 14 inches. 



At a slightly greater cost a stronger flume can be 

 built by the use of molds. The increased strength is 

 derived from a change in the mixture. In the machine- 

 made flume the mixtures of one part cement to five or 

 six parts of sand is lacking in strength, for the reason 

 that there is not enough cement to fill all the open spaces 

 in the sand. In using molds medium-sized gravel can be 



inches, but when the section is increased beyond about 

 240 square inches it pays better to slope -the sides outward 

 and adopt the form of the cement-lined ditch. At present 

 (March, 1910) the cost of rich concrete in place would 



Fig. 10. Wooden Check in Head Ditch. 



added to the sand and the mixture resembles that of the 

 common rich concrete. Such flumes can be built of al- 



Fig. 11. Section of Wooden Head Flume, Showing Opening and Gate. 



be about $9 per cubic yard for the larger flumes and 

 $10.50 for the smaller sizes. The quantity of concrete 

 required per linear foot of flume depends on its size and 

 the thickness of its sides and bottom. The dimensions 

 given in figure 13 are for light rather than for heavy 

 flumes and are designed for localities where there is little 

 frost. 



For large head flumes and laterals, many fruit growers 

 first carefully prepare an earthen ditch which has carried 

 water for at least one season and afterwards line the inner 

 surface with cement concrete. Figure 14 shows a section 

 of such a ditch. 



Several years ago 3,200 linear feet of head ditches 

 were lined for 26J/2 cents per foot; they were 14 inches 

 on the bottom with 18-inch sides and a 3-inch lining. The 

 cement cost $2,85 per barrel, gravel 75 cents per yard, 

 and labor $1.75 to $2.50 per day. 



Pipes and Standpipes. 



Head flumes, being placed on the surface of the 

 ground, interfere with the free passage of teams in 



Fig. 12. The Use of Low Check in Head Flume. 



cultivating, irrigating, and harvesting the crop. Dead 

 leaves from shade and fruit trees also clog the small 

 openings in the flumes. These and other objections to 

 flumes have induced many fruit growers of southern Cali- 

 fornia to convey the water in underground pipes and dis- 

 tribute it through standpipes placed at the heads of the 

 rows of trees. Both cement and clay pipes are used for 

 this purpose. 



The former are usually molded in 2-foot lengths, with 

 beveled lap joints, and consist of a 1 to 3 or 1 to 4 mix- 

 ture of cement and fine gravel and sand. The most com- 

 mon sizes are 6, 8, 10 and 12 inches in diameter, having 

 a thickness of shell in the 12-inch pipe of \ l / 2 inches 

 which s reduced to a trifle more than 1 inch in the 6- 



anv size from a bottom width of 10 inches to one inch pipe. Piping of this kind, when well made and care- 

 of 40 inches, and from a depth of 8 inches to one of 24 fully laid, will withstand a head of 10 to 16 feet. The 





