CONCRETE LINING FOR IRRIGATION CANALS. 61 



(10) Where conditions are adapted to its use, the type of joint 

 shown in figure 3, i, possesses some advantages over those previously 

 discussed. This is merely the carpenter's shiplap or half-timber 

 joint applied to concrete. It provides for all the expansion necessary 

 without weakening the lining by too wide a joint space. It also 

 permits a certain amount of "creeping" in the section without mis- 

 placement and furnishes an excellent opportunity to secure a water- 

 tight joint by the use of an elastic material like asphalt. 



(11) In adapting the shiplap joint to thin concrete linings a greater 

 thickness of lining is used at each joint. The sections shown in j, 1c, I, 

 and m, figure 3, represent this modification showing two joints and 

 methods of construction, as designed by A. F. Parker for the lining 

 of the Davis and Uinta Counties Canal in Utah. 



CONSTRUCTION METHODS AND COST. 



In submitting the following data an effort has been made to show 

 as fully as possible what constitutes current practice throughout the 

 West in the lining of old and new canals. The lack of space prevents 

 taking up many of these features in detail, but it has been the aim to 

 select representative work in the various localities and to point out 

 not only the good features of such work but to call attention to 

 doubtful practices in order to assist the engineer in the design and 

 execution of similar construction elsewhere. 



PATTERSON LAND & WATER CO., PATTERSON, CAL. 



About three years ago a series of pumping plants was installed to 

 raise water from the San Joaquin River to irrigate a tract of 14,000 

 acres, comprising the bulk of what is locally known as the Patterson 

 ranch. To prevent the loss of water by seepage the canals of tins 

 system were lined with a 3-inch layer of concrete and finished with a 

 j-inch plaster coat. 



The main canal at the river end (PL II, fig. 1) has a bottom 

 width of 7 feet, a vertical depth of 5^ feet, side slopes of 1^ to 1, and 

 a capacity of about 110 second-feet. Its capacity is reduced at 

 various points along its length, and at a distance of 2\ miles from 

 the intake the bottom width is 44 feet. 



After the excavation of each division the main canal was filled 

 with water and allowed to soak for from 6 to 9 days. It was then 

 trimmed and lined in 12 foot sections. The gasoline-driven concrete 

 mixer had a capacity of 75 cubic yards per day, winch provided 

 material to line 300 linear feet. The position of tins mixer when 

 operated and the methods employed in elevating the material and 

 delivering the concrete are shown in Plate II, figure 2. The concrete 

 used was a mixture of 1 part cement to 6 or 6^- parts of sand and 

 gravel. The plaster coat was proportioned 1 : 2 cement and river sand. 



