CONCRETE LINING FOR IRRIGATION CANALS. 69 
faces with straight-edges. The sides and bottom, were tamped 
lightly with wooden tampers and sprinkled before the lining was 
applied. The section lined has a bottom width of 11 J feet, side 
slopes of 1^ to 1, and a wetted perimeter of 26J feet. 
The three mixers used were operated on planks in the bottom of 
the ditch in advance of the work. With each mixer there was a 
crew of about 25 men and in addition a finishing crew of 5 or 6 men 
to dress the earth surfaces immediately ahead of the mixer. One 
rock crusher was also operated, the crushed rock being hauled an 
average of 2 miles. Most of the sand was procured from pits along 
the line of the canal and was used without screening. The lining 
was laid in 8-foot sections If inches thick, with strips of building 
paper in the joints between the sections. Four hundred feet of 
lining was considered a good day's work for a crew. 
A 1:3:4 mixture of concrete was used for most of the lining, but 
on one section a 1 :4 mortar applied 1 inch thick was considered just 
as good as the thicker lining of concrete, besides being much easier 
to apply. 
The lining in gravel sections leaked considerably the first season, 
presumably because allowed to dry too rapidly on account of lack 
of water for keeping it moist after laying. In work that was done 
the following year this difficulty was obviated by allowing a small 
amount of water to flow in the ditch soon after lining, using check 
dams to prevent its interference with construction. Men wearing 
rubber boots then waded along and with shovels or buckets threw 
water upon the side slopes at frequent intervals to keep the concrete 
wet while setting. Where lining had been placed on moistened sand, 
the results were better than in the sections through gravel, there 
being no perceptible leakage. Conditions in the gravel portion 
improved with the first year's use of the lined section, after which 
the seepage was considerably lessened. 
The various items of cost secured are as follows: 
Cost of lining canal of Lo,wer Yakima Irrigation Co. 
Laborers per day of 10 hours, without board $2. 50 
Man and team per day, without board 4. 50 
Contract price per square foot for mixing and laying concrete . 025 
Cement per barrel ! 3. 10 
Sand per cubic yard, approximately .50 
Total cost of lining, per square foot . 065 
Total cost of lining 9, 064. 49 
During February and March, 1911, the company placed additional 
lining, using practically the same methods above described, except 
1 This does not include an 8-mile haul over heavy roads. 
