2008-12-04_PERMIT FILE - C1994082 ‎(2)‎

• Permit No: C1994082
• IBM Index Class Name: Permit File
• Doc Date: 12/4/2008
• Doc Name: 10 Year, 24 Hour Postmine SEDCAD Demonstration
• Section_Exhibit Name: Tab 13 Attachment 13-3A.1 Appendix 13-3A.1-A
• Media Type: D
• Archive: No

•
YOAST MINE
Pond 10 -Watershed W-11
HYDROLOGIC INPUT PARAMETERS
SEDCAD4
Structure 2 - SWS1
WatershedW-11 (YPM-ti)
`Watershed Area: 343.6
Curve Number:
HYDROLOGIC
CURVE
WATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER AREA (acres)
Aspen/Mountain Brush Good (>70%) B 30 183.31
AspenlNlountain Brush Good (>70%) C 41 31.48
AspeniMountain Brush Gocd (?70%) D 48 3.49
Mesic Drainage
Fair (30% - 70%) B
48
9.73
Sagebrush Good (>70%) B 35 8.15
Sagebrush Gocd (>70%) C 47 2.17

Steep Mountain Erush Good >70% B
( ) 48 11.9
Steep Mountain Brush Good (>70%) C 65 2.42
Steep Mountain Brush Good (>70%) D 73 7'82
Bare D 98 2.06
Rock Outcrop Fair (30% - 70%) B 71 81.1
Reclaimed 343.6
Total
CURVE NUMBER 44
Vegetation cover conditions presented in Tab 10, Vegetation, Attachment 10-1, 1990/1992 Vegetation Baseline Report,
Yoast Study Area (ESCO Associates, 1993). Approved Yoast Mine curve numbers are presented in Attachment 13-12,
Fostmining Drainage and Sediment Contrcl , Table 13-12.1. Values were adapted from Urban Hydrology for Small
Watersheds, Technical Release No. 55, Sail Conservation Service, 1986.

SEDCAD 4
Structure 2 - SWSi
Watershed W-11 (YF_M-11)
Sedimentology: k factor
HYDROLOGIC SOIL
SOILS MAP UNIT/SOILS SERIES GROUP k FACTOR AREA (acres)
B 0.32 81.1
Reclaimed
B
0.37 80.6
XSD/E/F -Winevada -Splitro complex 4
23
2DiElF - Routt loam. C 0.24 .

68 - Zoltay barient clay loam
C 0 21

24
0

0.0
11 C/D - einco clay loam D . 2
0
12C/D -Buckskin loam C 0.19
0 28 .
17 0
27BID -Silas loam B
37
0
36.9
34C/D/E/F - Coutis silt loam
g
.
35ClD/E - Aaberg clay D 0.19
7
10
46C/D -Splitro loam C 0.24 .
75
6
53C/DIE/F -Winevada loam
B
0.23
.
0
3
66D/E/F - Foidel loam g 0.28
20
0 .
11 3
103 - Ustorthents-Cryoborolls complex D . 2
1
D 0.05 .
Rack Outcrop 343.6
Total
Weighted k Factor 0.30
Soils series information from Yoast Mine Permit Application Package (see Tab 9, Soil Baseline Study [Nyenhuis, 1994]).
Hydrologic Soil Group values are approved Yoast values (see Attachment 13-12, Table 13-12.2). The soil erodibility
factor, "k-Factor", values are presented in Attachment 13-12, Table 13-12.2.
TR-37
13-3A.1-A.24
Revised 02/08