66 
forms, which were also used on tangents, resulting in a much larger 
number of joints on the straight portions than good practice warrants. 
The joints were spaced 6 feet apart, and an attempt has been made 
to cover the seams with a coating of cement mortar. It is claimed, 
however, that these will eventually become filled with sediment, 
but the daily and seasonal contraction and expansion usually tend 
to enlarge rather than to decrease their width. 
Plate V, figure 2, shows the forms used for back-filling with 
puddled earth to prepare this canal for concrete lining. In Plate 
VI, figures 1 and 2, these forms have been removed and the channel 
is ready to receive the forms used in placing the concrete, as shown 
in Plate V, figure 2. Additional information on construction methods 
used with other useful data are to be found elsewhere. 1 
NORTHERN PACIFIC IRRIGATION CO., KENNEWICK, WASH. 
During the winter of 1910-11 this company lined 22,500 feet of 
ditches on the "Highlands" at Kennewick to eliminate heavy seepage 
losses. The soil through which these ditches are built is principally 
a fine sandy loam overlying gravel at a depth of 18 inches to 2 feet. 
One ditch 10,800 feet long, 3 feet wide on the bottom, with side 
slopes of \ to 1 and a vertical depth of 26 inches, is designed to 
carry 18 second-feet. Another ditch having in part a bottom width 
of 3i feet, side slopes of J to 1, and a vertical depth of 19^ inches is 
designed to carry 14 second-feet. This ditch is reduced to a bottom 
width of 2 i feet, but with the same side slopes and depth as the upper 
part. The concrete used was a 1:3:4 mixture of cement, sand, and 
crushed rock. 
In preparation for lining, center grade stakes were set and the 
bottom of the ditch brought to grade. Scantlings 2 by 4 inches 
were then placed across the bottom of the ditch at 12-foot intervals 
at right angles to the center line and flush with the subgrade. Three 
forms 12 feet long (PL VII, fig. 1) were then set in the ditch on the 
cross strips and centered. Earth was shoveled and tamped behind 
the forms to secure the desired section. There were 14 men in a 
crew on this work. 
After the earth sections were prepared in this way, 2 by 2 inch 
screeds (PL VII, fig. 2) were placed at intervals of 5 feet 8 inches 
and upon them forms 6 feet long were set on every other space. 
The concrete was mixed with a one-third yard mixer, wheeled to 
place and dumped on planks laid on top of the forms. It was then 
shoveled behind the forms and lightly tamped. Strips of sheet 
iron were inserted behind the forms to protect the slope while the 
concrete was being put in and also to prevent a too rapid loss of 
water from the mixture by its contact with the drier earth. These 
i Brit. Columbia Dept. Agr. Bui. 44 (1912). 
