2 BULLETIN" 376, XJ. S. DEPARTMEISTT OP AGRICULTTJEE. 



and operated in sizes up to 12 and 13 feet in diameter, tlie largest to 

 date being 13^ feet. This great increase in size and carrying capac- 

 ity has been brought about by providing yokes or cradles which 

 support the lower part of the pipe and thus prevent its collapse. 



Being well adapted to low heads and large diameters, such pipe 

 has proved one of the best and cheapest means of conducting large 

 volumes of water under low or medium heads from the sources of 

 supply to the places of use, regardless of whether the latter be a 

 power plant, a storage reservoir, the highest portion of an irrigated 

 tract, or the distributing reservoir of a municipahty. Stave pipe is 

 also frequently used in the constmction of inverted siphons, so 

 called, in conjunction with canals and grade pipe lines, to convey 

 water across gulches, ravines, or other depressions or down chute 

 drops to lower levels. It is likewise well adapted to rolling ground 

 where the building of canals on grade might be impracticable. 

 Finally, in the smaller sizes it is often used to convey and distribute 

 water to orchard tracts, manufacturing plants, and municipalities. 



The present economic importance of stave pipe in this country, 

 which arises from its adaptation to so many diverse uses, its wide 

 range of capacities, the ease with which it can be laid on rough ground, 

 and its cheapness when compared with other pressure pipes, has led 

 this department to investigate and report upon its merits and de- 

 merits. About three years ago a study was begun which comprised 

 the types, materials, methods of construction, and durabihty of wood 

 pipe. The results of this study were summarized in a recent depart- 

 ment bulletin.^ During the past two years another phase of the 

 same general subject has been investigated. This investigation has 

 included the making of tests and the collection of data on the flow of 

 water in wood-stave pipe, the results of which are embodied in this 

 report. Field work during the summer seasons of 1914 and 1915 

 consisted in the performance of 64 experiments on the fl:ow of water 

 in wood-stave pipes ranging in diameters from 8 inches to 13| feet, 

 while the office work consisted in the collection and analysis of avail- 

 able records of all previous experiments of a similar character and 

 the preparation of the data herein presented. From the results of 

 all experiments made, which combined reach a total of 286, there 

 has been deduced a new set of formulas for the flow of water in stave 

 pipe which is here presented. (See p. 48.) 



In another pubhcation ^ the writer has endeavored to show that 

 Kutter's formula is appHcable to the design of any open channel and 

 that the recommendations of the earlier writers on this subject con- 

 cerning the values of n (which comprises aU the influences retarding 



1 "Wood Pipe for Conveying Water for Irrigation, by S. O. Jayne, Bulletin 155, U. S. Department of 

 Agriculture. 



2 The Flow of Water in Irrigation Channels, by Fred. C. Scobey, Bulletin 194, U. S. Department of 

 Agriculture. 



