THE IBBIGATION AGE. 



145 



%-inch iron rod. The mold boards could be put in 

 one at a time, and one section 20 feet in length was 

 finished at one time. 



The mold frames having been put in position 

 and the lowest mold board placed on each side, a 

 layer of cement mortar was spread on the bottom ; 

 in this mortar were embedded cobbles, another layer of 

 irortar put on top of these cobbles, then successive 

 layers of cobbles and mortar until the side lining was 

 completed for the section. Mold boards were put on 

 as the lining was built up. The mixture was also 

 tamped during construction to assure the filling of all 



Form used for 

 //rung cana/s 



^^T^> 

 E.ar/'h Form /n place 



' 

 '.Form ,nP/ace 



-7 '- 



Lined canal when 



[. 4. Methods of Lining the Anaheim Water Company's Canal. 



spaces between cobbles. The ingredients used for the 

 mortar in this lining of the sides were one part of 

 cement to six parts of river sand. After the forms 

 were removed the sides and bottoms were finished with 

 a very thin wash of neat cement. 



The cost of cement was $3 a barrel, delivered on 

 the grounds. The cobbles were close at hand. The 

 cost of labor was $1.75 for common labor per nine- 

 hour day and $3.50 for masons per nine-hour day. 

 The total contract price for excavating and lining the 

 ditch was $25,000, or an approximate cost of 13 cents 

 per square foot, for the lining. 



CEMENT CONCRETE. 



The best examples of this kind of construction are 

 seen south of Los Angeles, near Orange, Santa Ana, 

 and Anaheim. In this vicinity two irrigation com- 

 panies, both diverting water from the Santa Ana river, 

 afford good illustrations of this efficient lining. These 

 two companies are the Anaheim Water Company and 

 the Santa "Ana Irrigation Company. 



The Anaheim Water Company has lined its main 

 canal and laterals with a thickness of concrete varying 

 from 4 inches for the larger canal to 2 inches for the 

 smaller laterals. The work of lining has been done 

 very thoroughly and with great care. If the canal is 

 an old earth ditch it is prepared for the lining and 

 carefully finished as described below. If the canal is 

 to be constructed and then lined the excavation is made 

 with shovels, or with teams where more economical, 

 the excavation being generally preceded by a thorough 

 irrigation to settle and soften the ground. The ex- 

 cavated cross-section is made larger than the finished 

 cross-section by the thickness of the lining. The bot- 

 tom of the ditch is carefully graded and tamped so as 



Fig. 5. Santa Ana Valley Company's Canal, Lined with Cement Concrete. 



to give a solid, smooth surface. A wooden form is 

 placed on the bottom of the excavated ditch. (Fig. 4.) 

 This wooden form is a trapezoidal trough with no 

 bottom, 16 to 20 feet long, depending on the size of 

 the ditch; to make it rigid the frames on which the 

 side mold boards are nailed are placed every two feet. 

 The trough is placed in such a position that the axis 

 of the ditch coincides with the axis of the form. Moist 

 earth from the excavation is shoveled behind this form 

 and is well tamped in successive layers; at least six 

 inches of earth on each side is packed solidly in this 

 manner. The earth form is now removed and before 

 the earth has had time to dry the lining is put on. 

 For the lining another form, smaller than the earth 

 form, is used. For some of the laterals this form was 

 given a peculiar shape (Fig. 4), with the idea of 

 strengthening the lining, and giving the ditch a slightly 

 curved form at the bottom, the corners being rounded. 

 The form is built with the usual side slopes of YZ on 1 ; 

 the slope is made natter for the lower eight inches, 

 where a slope of 1 on 1 is used. The depth of the form 

 is equal to the depth of the lined section plus the 



