THE FLOW OF WATER IN IRRIGATION CHANNELS. 65 
No. 107, R. S., Ten-Mile feeder, Idaho. Semicircumference 144 inches long. 
Flume clean. Coefficient n =0.013. 
No. 108, R. S., South Ridge Canal, section 1, Idaho. Semicircumference 60 inches 
long. Flume clean. Coefficient n=0.0139. 
No. 109, VMC+, King lateral extension, Uncompahgre project, United States 
Reclamation Service, Colorado. Excellently constructed as to alignment and grade. 
No. 108 flume. Coefficient n=0.0179. 
No. 110, VMC4-. Same system as No. 109 above. Same class of construction. 
No. 120 flume. Coefficient n=0.0177. 
No. Ill, VMC+. Same system as Nos. 109 and 110 above. Same class of con- 
struction. No. 96 flume. Coefficient n=0.0166. 
METAL FLUMES OF CORRUGATED IRON. 
No. 112, VMC+, Stewart Canal near Paonia, Colo. A No. 132 flume with numerous 
curves. Test in table covers whole flume. Value of n for portions of flume range 
from 0.0196 on a reach, most of which was on a curve of 300 feet radius to 0.0224 on 
a tangent. A similar test on a reach of No. 144 flume 278 feet long, with two curves, 
gave a value of 0.0230 for n. Coefficient n=0.0222. 
MASONRY-LINED SECTIONS. 
No. 114, R. S., Cottonwood flume, Idaho. Rubblestone fairly well laid. Some 
coarse sand in bed being earned as silt. Coefficient n=0.0163. 
EARTH CHANNELS. 
No. 118, W-14++, Interstate Canal, Nebraska. In same soil and with same gen- 
eral description as No. 120. This canal designed with frictional factor of 0.025, but 
on account of high velocity maximum discharge allowed is 830 second-feet instead 
of the 1,421 second-feet for which designed. Coefficient n=0.012. 
No. 121, SF-21**, Bear River Canal, Utah. Canal six years old. Section changed 
from trapezoidal with 1 to 1 slopes to present form. Bottom covered with sediment, 
but free from gravel and growth. Coefficient n=0.0134. 
No. 122, SF-12**, Bear River City Canal, Utah. Age and condition similar to 
No. 121 above of which this canal is a branch. Coefficient n=0.0135. 
No. 123, SF-15**, Corinne branch, Bear River Canal, Utah. Reach free from 
growth. Originally trapezoidal in clayey loam now segment of ellipse lined with 
smooth silt. Six years old. Coefficient n=0.0155. 
No. 124, SF-22**. Same canal as No. 123 above. Same conditions but carrying 
a small part of rated capacity. Coefficient n=0.0164. 
No. 125, VMC+, Fort Lyons Canal, Colorado. Carrying but 7 per cent of capacity, 
merely covering bottom. Slight curves at ends of reach. Bottom fine silt, merging 
into sand. In places boggy. Exceptionally smooth, regular, and free from im- 
pediments. Coefficient n =0.0165. 
No. 128, W-lb+--h Empire Intake Canal, Colorado. Straight, grade uniform, 
channel in firm sand, and gravel having no pebbles larger than one-half inch diameter. 
No vegetation. Two years old. Coefficient n =0.0170. 
No. 129, W-14 — K Same reach as No. 128 above with different discharge. Coeffi- 
cient n=0.0194. 
No. 131, VMC+, Jarbeau Power Canal near Rifle, Colo. New. First third of 
reach in clayey loam with few water- worn stones projecting. Rest of reach in clayey 
loam in which moss was starting. Coefficient n=0.0176. 
No. 136, SF-3**, Logan, Hyde Park and Smithfield Canal near Logan, Utah. In 
operation 15 years. Bottom and sides smooth earth and gravel up to 1 inch in diame- 
79256°— Bull. 194—15 5 
