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.t| 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 
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Fic. 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. 

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