2010-10-07_PERMIT FILE - C1994082

• Permit No: C1994082
• IBM Index Class Name: Permit File
• Doc Date: 10/7/2010
• Doc Name: Post Mining Channels SEDCAD Results/Channel YPM-1 to YPM-8
• Section_Exhibit Name: Tab 13 Attachment 13-12 Appendix 13-12.3
• Media Type: D
• Archive: No

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o Yoast ~iline
Postmine Channel Design
HYDROt.OGIC Ii~PUT PARAMETERS
SEDCAD 4
Channel YPM-1-3
Watershed ID -Structure 5 - SN1S1
West side subwatershed
Watershed Arsa: 9.5
Curve Number:
HYDROLOGIC CURVE AREA
WATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER (acres)
Reclaimed Fair (30% - 70%) B 71 6.28
Aspen/Mountain Shrub Good (>70%) B 30 3.23
Total 9.51
CURVE NUMBER 57
SEDCAD 4
Channel YPM-1-3
Watershed ID -Structure 5 - SWS2
East side subwatershed
Watershed Area: 11.6
Curve Number:
HYDROLOGIC CURVE AREA
1PIATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER (acres)
Reclaimed Fair (30% - 70%) B 71 10.50
Aspen/Mountain Shrub Good (>70%) B 30 0.30
Aspen/Mountain Shrub Gocd (>70%) C 41 0.40
Sagebrush Good (>70%) B 35 0.25
Sagebrush Good (>70%) C 47 0.15
Total 11.60
CURVE NUMBER 68
Vegetation cover conditions presented in Tab 10, Vegetation, Attachment 10-1, 1990/1992 Vegetation
Baseline Report, Yoasf Study Area (ESCO Associates, 1993). Approved Yoast Mine curve numbers are
presented in Attachment 13-12, Postmining Drainage and Sediment Control ,Table 13-12.1. Values were
adapted from Urban Hydrology for Small Watersheds, Technical Release No. 55, Soil Conservation Service,
1986.

TR-37
13-12.3-20
Revised 02/08