44 BULLETIN 339, U. S. DEPARTMENT OF AGRICULTURE. 
meter determinations at the head of the main canal of each system 
(Pl. III, fig. 2). The gages were read by men employed for the pur- 
pose, and the discharge curves were based in each case upon 20 to 
30 current-meter ratings which were made during the season at each 
station by two to six hydrographers with different meters. The areas 
irrigated under each system and the crops that were grown were 
Getecauned by a house-to-house canvass of each farm. 
BOISE VALLEY FARMS. 
The quantity of water delivered to a total of 428.64 acres on 16 
farms in the Boise Valley was determined during the season of 1912. 
The farms imcluded were located in the heart of the vailey, near 
Meridian, and represented typical Boise Valley conditions, and the 
average use of water at the individual farmer’s head gates in the dis- 
trict durmg the season was found to be 2.56 feet per acre, the quantity 
wasted not having been deducted. Of the 428.64 acres included, 
144.84 acres were devoted to alfalfa, pasture, and other hay grasses, 
the remainder to grains, potatoes, and orchards. The soil of the 
district is nearly uniform and consists of a clay loam 3 to 8 feet in 
depth, underlain with a rather compact eravel. The water for irriga- 
tion purposes in the above district is used with more than the average 
care, and the use of water shown by the measurements Corresponds 
very closely with the requirements shown by the variation experi- 
ments. 
SALMON RIVER PROJECT FARMS. 
The water applied to a total of 978.22 acres on 12 farms of the 
Salmon River project was measured during the season of 1913, the 
area involved having all been determined by transit surveys. The 
soil of the district is a clay loam 2 to 6 feet in depth underlain by lava 
rock. The total area involved consisted of 200.73 acres of hay and 
pasture grasses, and 777.49 acres of grain, potatoes, and orchards, and 
the use of water by the farmers varied from 0.77 to 5.30 acre-feet 
and averaged 2.08 acre-feet for the entire area. This was the first 
year some of this land had been irrigated, and it is believed the 2.08 
acre-feet, with one or two exceptions, represented the average use 
of water on the entire project at that time. The quantities wasted 
from these tracts were not measured. 
WATER DIVERTED BY TYPICAL CANAL SYSTEMS. 
The canal systems investigated in order to determine their head- 
gate diversions consisted of the Riverside, Farmers’ Cooperative, 
Farmers’ Union, Settlers’, Boise Valley, Pioneer, and Eureka, typical 
canals of the Boise Valley; the Randall Canal, and the Clark and 
Edwards in the Upper Snake River Valley; and the South Side 
Twin Falls Canal, which irrigates approximately 200,000 acres on the 
