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a wooden pipe system, which can be kept full of water only part of the time, 

 when the cost of the wooden pipe system would be in excess of 1.3 times the 

 cost of the flume system. Also the flume system is more economical when 

 the cost of a wooden pipe system which can be kept full of water all the 

 time is 1.8 times the cost of the fliiiiie system. As stated above, a wooden 

 pipe system under average conditions will cost about twice as much as a 

 wooden flume system; therefore, if the above cost alone is considered a 

 wooden flume system is more economical. But there are other relative 

 advantages and disadvantages which should be considered. 



The third type of system that is, the wooden pipe system which can be 

 kept full all the year around without freezing has the advantage that it 

 can be used for domestic supply. The other two types require a separate 

 domestic system if domestic water is desired. But it is not always possible 

 to combine the two, for often the source of supply from which the irrigation 

 water is obtained may be frozen in the winter or it may be so polluted that 

 it is not safe drinking water and if it must be filtered or treated to purify 

 it, it would be very poor economy to have to purify the irrigation water as 

 well as the domestic water which are carried in the same pipe. If these 

 conditions exist a separate domestic system is preferable. 



PERMANENT CONSTRUCTION. 



The short life of wooden flume and wooden pipes and the increasing 

 value of water have led to more permanent and better class of construction 

 throughout the arid region. Wooden flumes on trestles are being replaced 

 by steel flumes; wooden flumes resting on the ground or bench flumes which 

 were necessary to carry the water on steep hillsides or through porous 

 ground, are being replaced by concrete flumes and concrete lined channels. 

 Concrete linings are being constructed wherever the seepage losses must be 

 prevented because of the value of water loss or because of the damage 

 caused to adjacent land by the seepage water. Concrete pipes, both plain 

 and reinforced, which a few years ago were only used in southern Cali- 

 fornia, are now being used to some extent in many of the irrigated dis- 

 tricts of Washington, Oregon, Idaho, and other western states and their 

 use is growing. The use of plain concrete pipe is, however, limited to small 

 heads and concrete pipe reinforced with steel can only be used for moderate 

 heads. So far reinforced concrete pipe has been used only where pressure 

 heads are under 100 feet, and some manufacturers of reinforced concrete 

 pipe will guarantee them for heads as large as 150 feet. But it can not be 

 expected that cement pipe will replace wooden pipe where pressures are 

 large and as much of the land covered by irrigation systems in British Co- 

 lumbia is irregular and the surface has a steep slope which often produces 

 high pressures, the use of reinforced concrete pipe can not be adopted in 

 general. For such locations wooden pipes, especially if they can be kept 

 full and protected from freezing, are the best solution. On steep slopes 

 which are fairly uniform with no deep depressions, it is possible to so regu- 

 late the pressure that cement pipes can be used. 



During the past two years some of the irrigation companies of British 

 Columbia have realized the economy of improved method of construction 

 and some of the work which has been done and is being done is equal to 

 any in the country. Excellent examples of permanent construction are 

 found on the systems of the Kelowna Irrigation Company and the South 

 Kelowna Company, near Kelowna, and the Fruitlands Irrigation and Power 

 Company, near Kamloops. Some of the systems installed and others which 



