8 The; Colorado Experiment Station 
ways in case of breaks in the banks of the canal. The wasteway 
consists of a 10x3 feet hole, cut lengthwise in the bottom of the 
flume near the middle of its length, and opening into a wooden 
box encasing the bottom of the outside of the flume. Wasteway 
gates are built into one side of this box. The flumes experimented 
upon are from 70 to 90 feet in length and with semi-circular arcs 
of 168 inches. Duplicate experiments were made upon each 
flume as a check upon the value of the coefficient. Table 1 shows 
the results of these experiments. 
TABLE 1—HYDRAULIC ELEMENTS IN FLUMES WITH WASTEWAYS. 
Length 
Dis¬ 
Area of 
Mean Wetted 
Hydrau¬ 
Slope 
Co¬ 
Co¬ 
of 
charge 
Wetted 
Veloc - Perim- 
lic 
feet 
efficient 
efficient 
Section 
Tested 
sec-ft. 
Section 
sq. ft. 
ity ft. eter 
per sec. lin. ft. 
Mean 
Radius 
per 
foot 
(c) 
(n) 
79.6 
15.72 
5.83 
2.70 
7.02 
0.83 
0.00216 
63.6 
0.0211 
79.6 
27.68 
9.50 
2.91 
8.32 
1.14 
0.00168 
66.4 
0.0219 
69.6 
14.05 
9.12 
1.54 
8.23 
1.11 
0.00043 
70.6 
0.0202 
69.6 
22.22 
12.93 
1.72 
9.53 
1.36 
0.00043 
71.2 
0.0210 
The results of these experiments indicate that the effect of 
the wasteway in the flume of short length, is to reduce its carry¬ 
ing capacity by increasing the coefficient of friction. For flumes 
of this class, less than 100 feet long and having wasteways similar 
to the above type, a mean value for (n) of 0.021 is indicated. 
FLUMES ON TANGENTS WITH NO IRREGULAR¬ 
ITIES. About 3,000 feet of flume had been constructed in the 
winter of 1912-13 upon the Garland canal of the Trinchera Irri¬ 
gation District, near Blanca. The length of semi-circular arc was 
168 inches. Because of the excellency of the construction, uni¬ 
form grade and perfect alignment it was especially well adapted to 
purposes of experiment. (Plate I.) 
Tests were made upon the tangents between curves in April, 
I 9 I 3* 
Experiments were also made upon a flume of the Minnesota 
canal near Paonia, in October, 1913. The grade of this flume was 
not uniform throughout its entire length, so that only two sections 
were tested, but these had uniform grade and sufficient fall to 
allow of an accurate determination of the slope. No transverse 
bracing whatever existed in this flume, and during the three sea- 
sobs it had been in operation sag had taken place in cross-section 
and caused a displacement of the uprights and drawing together at 
the top. For this reason the mean wetted area was obtained by 
taking cross-sectional depths, which were plotted, and the wetted 
perimeter was measured with a pair of dividers. 
Table 2 gives the results of these tests: 
