WOOD PIPE FOR CONVEYING IRRIGATION WATER. 



13 



Due to general advance in the price of lumber in late years and the 

 reduction in the cost of cement, concrete has come to be the material 

 principally used for structures of this kind. 



For municipal water supplies, intakes may require elaborate con- 

 trolling works, including settling chambers, sand gates, etc., and in 

 some localities steam pipes for heating the receiving chamber are 

 provided as a precaution against freezing. 1 But ordinarily for irri- 

 gation or power lines such structures need not be elaborate or expen- 

 sive. An example of this type of construction is shown in figure 2, 

 the intake of a 72-inch inverted siphon on the Kings Hill irrigation 

 project, Idaho. Another example in which the water enters the pipe 



PLAN 



Fig. 2. — Intake of 72-inch pipe on King Hill project. 



from an earth ditch instead of from a flume is illustrated by figure 3, 

 intake of Poisin Basin siphon, Kings Hill project, Idaho. In the 

 foregoing examples the concrete was poured around the pipe so as to 

 form a tight connection, and the portions so incased were given addi- 

 tional bands. In some instances a section of cast iron or steel pipe is 

 set in the concrete and a junction is made between that and the wood 

 pipe. In other instances where the concrete and wood are joined, 

 space for calking is provided by making the opening through the 

 concrete slightly larger than the external diameter of the pipe. 

 Either of the alternatives from the first plan given makes it possible 

 to replace or repair the end of the wood pipe with greater facility, 

 though the calked joint may be more difficult to keep water-tight. 



*Engin. Rec, 66 (1912), p. 425. Intake of Denver Union waterworks. 



