2013-10-31_REVISION - M1977284 ‎(3)‎

• Permit No: M1977284
• IBM Index Class Name: REVISION
• Doc Date: 10/31/2013
• Doc Name: Drainage Design Plan Mineral Joe Mine
• From: Cotter
• To: DRMS
• Type & Sequence: AM1
• Email Name: TC1
• Email Name: SJM
• Media Type: D
• Archive: No

Mineral Joe Mine - Drainage Design Plan 21
4.4.2 Middle Diversion Structure (MDS)
The MDS intercepts stormwater runoff from upslope sub -basin N -D (0.91 acres) and a fraction of the
adjacent sub -basin (0.079 acres). The MDS diverts this stormwater eastward into the adjacent sub -basin,
east of the mine site (Figure 1). The MDS channel is normally dry, and flows only in response to
precipitation events.
The MDS channel was inspected on May 28, 2013 and seven cross sectional profiles were surveyed along
the 384 -ft channel (Plate 4). The survey results are presented in Attachment 3 and are summarized in Table
12. The MDS channel is broad and shallow, with an average top width of 12.3 feet and an average side
slope ratio of 4.8:1. The average local bedslope is 0.0778 for the seven profiles and 0.0933 for the entire
channel.
Based on the surveyed channel geometry, the current MDS was modeled with a 0.9 -ft bottom width and
4.8:1 ft side slopes in the WinTR -55 model run CC- CP_03.w55. Model results are presented in Section
5.2 (channel capacity) and 5.3 (channel stability).
Table 12. Middle Diversion Structure Channel Geometry
Profile ID:
MDS -PI
MDS -P2
MDS -P3
MDS -P4
MDS -P5
MDS -P6
MDS -P7
Avg.
Area, bank full (W):
7.92
7.36
11.22
11.84
11.34
7.95
12.36
10.0
Area,0.5 -ft freeboard (ft'):
1.52
2.62
5.86
1.63
3.78
2.03
2.67
2.9
Area,1 -ft freeboard (fe):
0.00
0.14
1.94
0.00
0.91
0.13
0.48
0.5
Top Width (ft):
13.30
11.63
12.10
11.70
12.90
11.10
13.70
12.3
Bottom Width (ft):
0.00
0.00
0.00
4.15
2.00
0.00
0.00
0.9
Side Slope Ratio, Left Bank:
9.50
6.44
4.84
7.01
6.16
5.47
5.16
6.4
Side Slope Ratio, Right Bank:
3.80
3.42
1.81
3.33
2.50
2.03
5.47
3.2
Average Side Slope Ratio:
6.7
4.9
3.3
5.2
4.3
3.8
5.3
4.8
Local Channel Bed Slope (ft):
0.1376
0.0356
0.0936
0.0400
0.0628
0.0631
0.1119
0.0778
Channel Profile
MDS -P2
F 0.00
L
a
d
1.00
d
C
C
A
L
U 2.00 -
0 1 2 3 4 5 6 7 8 9 10 11 12 13
Distance (ft)
Channel Profile
MDS -P5
F 0.00
t
a
m
0 1.00
Z
C
G
t 2.00 --
L) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Distance (ft)
Figure 7. Typical Channel Profiles Measured in Middle Diversion Structure
414813.131029 Whetstone Associates