UNITED STATES DEPARTMENT OF AGRICULTURE 
LOGAN WALLER PAGE, Director 
Washington, D. C. PROFESSIONAL PAPER April 21, 1916 
EXPERIMENTS ON THE ECONOMICAL USE OF 
IRRIGATION WATER IN IDAHO. 
By Don H. Bark, Irrigation Engineer. 
CONTENTS. 
Page. Page. - 
MMHNOCUGHIOMMAE sR eta es cee ccisc ccc ctieccto 1 | Measurement of water used on farms and 
Hlanoninvestigaylon. 5+... -.---- - <j. ss-7-- es 2 under complete canal systems......-.-...- 43 
Weather conditions in Idaho during the in- Seepage investigation. ..-..........-=.--.--- 47 
IVES TIC AUION SS o.oo 2 ie oc Serco sacle eel - se 6 | Survey of waste land in Idaho............... 52 
Results obtained during 1910, 1911, 1912, and . Proper duty of water for Idaho.............. 56 
TONS. ose cace tees eeee eee ean ers Eerer eee 9 
INTRODUCTION. 
This bulletin contains the results of experiments made in coopera- 
tion with the State Land Board of Idaho to determine the quantities 
of water needed to produce the ordinary farm crops on the types of 
soil common to that State. The experiments, in addition to investi- 
gations strictly bearing on such irrigation requirements, included 
certain supplementary investigations. 
The irrigation-requirement experiments extended from 1910 
through 1913 and consisted in applying different quantities of water 
to plots receiving similar treatment except for this factor. It is con- 
sidered that these experiments fix within reasonable lmits the 
amount of water which must be delivered to fields to produce profit- 
able crops under the conditions described. The supplementary 
experiments were made for the purpose of determining how much 
additional water must be allotted to cover waste and losses between 
the point of diversion and the fields to be irrigated. 
The conclusions contain a discussion of the factors affecting irriga- 
tion requirements in actual practice. 
Notre.—The work on which this bulletin is based was done under a cooperative agreement between the 
Office of Experiment Stations and the State Land Board of Idaho, several of the canal companies and the 
railway companies operating in Idaho contributing to the expense of the work. The bulletin will be of 
interest to officials administering the water supply of the Western States, to students of irrigation prac- 
tice, and to farmers. 
13653°—Bull. 339—16—1 
