40 
The Colorado Experiment Station. 
VALUES OF “C” GIVEN BY KUTTER’S FORMULA. 
Fall 1.06 ft. per mile 
Fall 2.11 ft 
1 
per mile 
Fall 5.28 ft. per mile 
Rough¬ 
ness “N” 
.017 
.020 
.025 
.030 
.017 
.020 
.025 
.030 
1 
.017 
.020 
.025 
.030 
Hydraulic 
Depth 
1/2 ft. 
69 
56 
43 
34 
71 
58 
45 
35 
73 
59 
46 
36 
1 ft. 
S3 
69 
54 
44 
85 
70 
55 
45 
86 
71 
56 
45 
2 ft. 
97 
82 
64 
54 
98 
83 
65 
54 
98 
83 
66 
54 
3 ft. 
105 
89 
72 
59 
105 
89 
71 
59 
105 
89 
71 
59 
4 ft. 
111 
91 
76 
63 j 
1 
110 
1 
94 
76 
63 
110 
93 
75 
63 
OTHER FORMULAE. 
Attempts have been made with some success to develop for¬ 
mulae in which the coefficient is constant for the same class of 
channels, irrespective of size and slope, but with varying expon¬ 
ents of “r” and “i,” not constant as in the one on page 37. Such 
are Sullivan’s, Tutton’s, the Williams-Hazen, where the expon¬ 
ents of “r” are 3/4 in Sullivan’s, 2/3 in Tutton’s, 0.63 in W.-H.; 
and the exponents of “i” 1/2 in both Sullivan’s and Tutton’s, and 
0.54 in W.-H.. 
These formulae give much promise but are not convenient to 
use without tables which are not available execpt in the case of 
the Williams-Hazen,* and in each case requires the transformation 
of known measurements into the terms of these formulae so as to 
have a guide for the selection of “c” in that class of cases. Until 
there is a larger collection of special measurements, and also an 
expression in the special formulae, it is better to be contented with 
Kutter’s. A 
*Hydraulic tables by Williams and Hazen, Pub. Jno. Wiley & Sons. 
