RURAL ENGINEERING. 



585 



Results (iiid cost (if rarious tiiiiiif/s for ditches. 



Description of lining. 



Per cent 



saving. 



Experi- 

 mental cost 

 of lining, 

 per sq. ft." 



Estimated 

 cost (in 

 practice) 

 of lining 



per sq. ft." 



Cement concrete, 3 in. thick 



Cement lime concrete, 3 in. thick 



Cement mortar 



Heavy oil, 31 gals, per sq. yd 



Clay puddle, 3J in. thick 



Heavy oil, 3 gal. per sq. yd 



Heavy oil, 2J gal. per sq. yd 



Thin oil, 2J gal. per sq. yd 



Earth (no lining) 



86.6 

 65.5 

 63.3 

 50.4 

 47.8 

 38.0 

 27.3 

 7.3 

 0.00 



Cents. 

 8.3 

 8.3 

 3.88 

 1.20 

 3.90 

 1.00 

 .77 

 1.00' 



Cents. 



7.5 



7.5 



3.25-3.50 



1.20 



1.20 



1.00 



.77 



.80 



" Excluding the preparation of the ditch. 



" While there is no doubt that cement concrete is tlie most efficient as re- 

 gards seei>age, it is also the most expensive, being more than six times the 

 cost of the heavy oil lining (3§ gallons per square yard), which saves 50.4 i)er 

 ceirt of the water which would seep were the ditch not lined. This saving with 

 the concrete ditch is 86.6 per cent, or If times as large. Where water is very 

 valuable there is no doubt but that the concrete ditch is more permanent and 

 economical. But where the water is not so scarce and a little waste will do 

 no damage, the expense of lining the ditch with oil may be justified, while a 

 more expensive lining would be impracticable. . . . But . . . the advantag;e of 

 lining a canal is not alone the decrease in seepage; other factors should be con- 

 sidered. ... (1) The prevention of growth of vegetation is an important item 

 and is quite an expense, when in most cases the ditch or lateral must be cleaned 

 out several times during an irrigation season; (2) the resistance to scouring, 

 on which depends the velocity which the water can be given; (3) the pre- 

 vention of burrowing into the banks and bottom of ditches by squirrels and 

 gophers. 



" That oil will prevent vegetation and the burrowing of animals in the banks 

 and bottom of the ditch is clearly shown by [an] example near Lemoore. 



" That oil will prevent scouring to a great extfflit and will allow a much 

 higher velocity of flow of water than the earth ditch may be expected when 

 we consider its resistance to wave action at the Ivanhoe Reservoir, and the 

 resistance of oiled roads to cutting under the action of running water. This 

 toughness of oil lining was noticed in filling the experimental ditches each 

 iiiorning. When the water carried by the wooden flume discharged into each 

 ditch through the gate it had a full of at least 1 ft. It was difficult to pre- 

 vent the sloping ends of the earth and puddle ditches from being badly cut up 

 by the erosive force of the falling water. These ends had to be well protectecl 

 with heavy canvas, and even then erosion could not be altogether prevented. 

 The ditches lined with oil resisted the erosion and showed no cutting, although 

 they were not protected with canvas. . . . This resistance to erosion will 

 permit a saving of cross-sectional area due to the possibility of giving the water 

 an increased velocity. The higher velocity will prevent the deposition of silt to 

 a great extent and there will be a conse<iuent decrease in the cost of operation 

 and maintenance." 



On the artificial irrigation of field crops, I. I. Streltsev (Vyednm. Selsk. 

 Khoz. Promuish.. 1905, Nos. ',1, J,3 ; abs. in Zhur. Opnitn. Agron. [Russ. Jour. 

 Erpt. Landir.], 8 (1907), No. 1, p. 78). — The author sums up his observations 

 during years on the Government Kamensk Irrigated Field in the Bakhmut 



