38 The: Colorado Experiment Station 
there are no known reasons for doubting the accuracy of the ex¬ 
perimental data, it is probable that the pipes in question were not 
clean, and these data indicate their interior condition. It is not to 
be understood that values for (n) of 0.027, or even 0.019, are 
recommended for wood stave siphons properly constructed and in 
good condition of alignment and interior. The siphons which were 
expected to be in good condition did show low values of (n), but 
the entire data indicate the condition that may be obtained in 
siphons after a few years of operation where no provision is made 
for cleaning them. 
TABLE 9—HYDRAULIC ELEMENTS OF WOOD STAVE SIPHONS. 
Name of 
Siphon 
u 
o> 
o> 
£ 
d 
0 ) 
f-i 
3 
i/i 
09 
<13 
U 
PH 
a p, 
21 (2 
£ 
£ 
* ^ 
d 0 
§ ^ 
I 
o 
cu 
w 
03 
be 
Sh 
d 
r~^ 
O 
W 
* 
o 
(1) |(2) | (3) | (4) | (5) | (6)| (7) | (8) j (9) | (10) | (11) 
Redlands Mesa (b) .| 48 | 486 j 51120.3411.62 j 0.497 j 1.0211. 49.4 |.0271j.1005 
Redlands Mesa (a) .| 48 J 515 J 66 j 20.4411.63 j0.202 | .3921 82.2 |.0172 |.0380 
Jones Extension .| 36 | 815 j 115.2512.16 10.5151 .632 j 98.6 |.01401.0262 
Arkansas Val. Conduit No. 13 . j 60 | 363 | 37 149.70 j 2.53 j 0.669 j 1.843 j 52.8 j.0275 |.0925 
Arkansas 
Val. 
Conduit 
No. 
14. 
j 60 
j 1621 
99 
49.70 
2.53 
1.045 
0.644 
89.7 
.0169 
.0324 
Arkansas 
Val. 
Conduit 
No. 
12. 
| 60 
| 426 
55 
50.73 
2.58 
0.596 
1.400 
61.8 
.0238 
.0675 
ArKansas 
Val. 
Conduit 
No. 
6. . 
I 60 
323 
26 
53.99 
2.75 
0.368 
1.141 
72.7 
.0204 
.0486 
Arkansas 
Val. 
Conduit 
No. 
8. . 
| 60 
^ 405 
59 
53.99 
2.75 
0.408 
1.007 
77.6 
.0193 
.0429 
Arkansas 
Val. 
Cons. 18 & 
19. 
j 58 
12278 
104 
52.68 
2.88 
1.162 
0.510 
116.0 
.0134 
.0192 
Arkansas 
Val. 
Conduit 
No. 
17 . 
| 54 
544 
83 
52.68 
3.31 
0.942 
1.732 
75.0 
.0195 
.0458 
Arkansas 
Val. 
Conduit 
No. 
7. . 
| 54 
[2563 
60 
53.99 
3.39 
2.205 
0.861 
109.1 
.0139 
.0220 
Arkansas 
Val. 
Conduit 
No. 
9. . 
j 54 
803 
77 
53.99 
3.39 
1.438 
1.790 
75.6 
.0193 
.0449 
• *Value of (c) in Chezy Formula V = c-y/rs. 
**Value of (n) in Kutter’s Formula. 
***Value of (f) in formula for lost head due to friction and curvature. 
L V 
h = f — - 
d 2g 
THE EFFECT UPON “n” OF VARIATION IN HYDRAULIC 
FACTORS 
Many times in determining the carrying capacity to be as¬ 
signed to a channel under construction, doubt arises as to the 
proper coefficient of roughness to use, or as to what safety factor 
to apply for any possible future variation in the value of the co¬ 
efficient. 
Table io illustrates the manner in which the discharge flue- 
