2014-01-29_HYDROLOGY - P2009025 ‎(8)‎

• Permit No: P2009025
• IBM Index Class Name: HYDROLOGY
• Doc Date: 1/29/2014
• Doc Name: Baseline Hydrologic Monitoring Plan
• From: Black Range Minerals
• To: DRMS
• Email Name: TC1
• Media Type: D
• Archive: No

Appendix D - SOP for Stream Flow Measurement - Hansen Project 6
Table 1. Coefficients and Exponents for Parshall Flumes
Throat
Width
Coefficient
(C)
Exponent
(n)
1 in
0.338
1.55
2 in
0.676
1.55
3 in
0.992
1.55
6 in
2.06
1.58
9 in
3.07
1.53
1 ft
3.95
1.55
2 ft
8.00
1.55
3 ft
12.00
1.57
4 ft
16.00
1.58
5 ft
20.00
1.59
6 ft
24.00
1.59
7 ft
28.00
1.60
8 ft
32.00
1.61
10 ft
39.38
1.60
12 ft
46.75
1.60
15 ft
57.81
1.60
20 ft
76.25
1.60
25 ft
94.69
1.60
30 ft
113.13
1.60
40 ft
150.00
1.60
50 ft
186.88
1.60
Discharge Calculations for the Portable Cutthroat Flume
Discharge calculations for the portable Cutthroat flume assume free -flow discharge conditions exist and
follow the form:
where:
Q = CfhUnf
C and n = constants
Q = discharge (ft3 /s)
Cf = the free flow coefficient
h„ = the upstream gauge reading (ft)
Bf = the free flow exponent
The value of of can be read directly from Figure 1. The value of the free flow coefficient, Cf is a function of
the flume's length and throat width:
where:
Cf = KfW 1 025
W = the throat width in feet; and
Kf = the flume length coefficient (Figure 1)
4153A.140129 Whetstone Associates