Washington, D. C. PROFESSIONAL PAPER October, 1922 
By Cari Rouwer, Irrigation Engineer, 
Division of Agricultural Engineering, Bureau of Public Roads. 
THE FARMER’S SHORT-BOX MEASURING FLUME.' 
| 
CONTENTS. 
Page. Page. 
Se 6 oa a 1 | Submerged-fiow discharge diagrams-......-.-. 9 
sane GIMTSION. ~~. - 2-2-2 5----2----- 2°) Speeial- bests. Jon) | Oh Poe 2 a eee 12 
Derivation of discharge formulas.......-.... 5. | SURO RTy 2" > So. 2 ae et ae ee ee 13 
Free-flow discharge table...-............---- 6 
Many devices have been developed for the measurement of the 
water delivered to farmers for irrigation, and of these the standard 
weirs have been most carefully calibrated. When weirs of this type 
have been correctly designed, installed, and maintained they give 
accurate results. In some localities, however, especially in the older 
irrigated sections, types of weirs have come into use that are not 
standard and that consequently can not give accurate results unless 
new calibrations are made. For one of the many weirs of this type 
the following tables and charts have been prepared in order that the 
structures already installed may be successfully used in the distribu- 
tion of water. 
The farmer’s short-box measuring flume, as shown in Figure 1, 
is a weir with completely suppressed end cortractions and a partially 
suppressed bottom contraction. No provision is made for the aera- 
tion and lateral expansion of the nappe, as-required in the standard 
weir without end contractions. The floor of the weir box is level, 
and is placed at the grade of the ditch in which it is installed. The 
weir bulkhead is variable in height, depending on the conditions it 
has to fulfill, and it is usually made from the commercial sizes of 
2-inch lumber. No attempt is made to keep a sharp edge at the 
crest. As shown in the figure, the bulkhead is not fixed, but may 
be removed, by sliding it out of the grooves in the walls of the weir 
1 The work upon which this bulletin is based was done with the assistance of M. L. Lightburn and A.B. 
Crosley under the direction of R. L. Parshall, senior irrigation engineer, in charge of the irrigation investi- 
gations in Colorado. The bulletin was prepared in cooperation with the Colorado Agricultural Experi- 
ment Station. 
3137—22 
