CONCRETE LINING FOE IRRIGATION' CANALS. 67 



strips were raised as the filling progressed. Two crews of 5 men 

 each placed the concrete behind the forms, 2 men wheeled to each 

 crew, and about 5 men were employed to move forms, etc. About 

 6 men were in the mixing crew and 2 others plastered rough places 

 in the lining. 



Water kept in the finished ditch a few hundred feet in the rear 

 of the work (PI. VII, fig. 3), was pumped ahead to the mixer with a 

 small gasoline engine. 



The engineer stated that in one hour a crew could place about 

 six sections, or 34 lineal feet, of the lining in the ditch having a 

 3-foot bottom. 



On some of this work done during freezing weather, canvas covers 

 were placed over the ditch. Under these covers iron pipes were 

 laid through which steam was run from a steam boiler during the 

 night. 



Rock gathered from various places within the locality was crushed 

 and hauled from 1 to \\ miles. Six men collected the rock, 4 men 

 operated the crusher, and about 7 teams hauled the crushed rock 

 to the place of use. The cost of the crushed rock was not obtainable, 

 but other items of expense were as follows: 



Cost of labor and materials for lining Northern Pacific Canal. 



Cement per barrel delivered at works, approximately $3. 00 



Sand delivered by contract, per cubic yard 1. 75 



Laborers per hour, without board 25 



Teams per hour, without feed 35 



TRUCKEE-CARSON PROJECT, NEVADA. 



A part of the main lower Truckee Canal constructed in 1904 and 

 1905 by the United States Reclamation Service was lined with 

 concrete. Much of this lining was placed without the use of expan- 

 sion and contraction joints. In November, 1911, about six years 

 after the lining was completed, Mr. F. L. Peterson, irrigation engineer 

 of this office, made a careful examination of the lined portions of this 

 canal to determine if possible the effect produced by the lack of 

 joints. Plate VIII, figure 1, is a general view of the lined canal 

 opposite the railroad siding at Gilpin, Nev. Here the canal is 

 excavated for the most part in solid rock and lined with 4 inches of 

 concrete. In the same plate are shown fractures in the lining after 

 a thin mortar coating had been placed over the seams. Plate VIII, 

 figures 2 and 3, gives a closer view of two of the fractures, the latter 

 one of which has been repaired. 



The general specifications for the concrete used on this work 

 provided : 



The concrete to be used on all the structures and tunnels on this canal will be 

 composed of Portland cement, sand, and gravel or broken stone, in the proportion of 



