2008-01-16_PERMIT FILE - C1994082A ‎(2)‎

• Permit No: C1994082A
• IBM Index Class Name: Permit File
• Doc Date: 1/16/2008
• Doc Name: Sediment Ponds SEDCAD4 Results
• Section_Exhibit Name: Tab 13 Attachment 13-12 Appendix 13-12.1
• Media Type: D
• Archive: Yes

Yoast Mine
Pond 12A Design
HYDROLOGIC INPUT PARAMETERS
SEDCAD 4
Channel YPM-6-2
Watershed ID -Structure 9 - SWS1
Watershed Area: 17.2
West side subwatershed
Curve Number:
HYDROLOGIC CURVE AREA
WATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER (acres)
Aspen/Mountain Shrub Good (>70%) C 41 4.78
Reclaimed Fair (30% - 70%) B 71 11.34
Reclaimed Topsoiled, No Vegetation B 86 1.03
Total 17.2
CURVE NUMBER 64
SEDCAD 4
Channel YPM-6-2
Watershed ID -Structure 9 - SWS2
Watershed Area: 20.3
East side subwatershed
Curve Number:
HYDROLOGIC CURVE AREA
WATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER (acres)
Reclaimed Topsoiled, No Vegetation B 86 9.20
Reclaimed Fair (30% - 70%) B 71 8.13
Aspen/Mountain Shrub Good (>70%) D 48 1.01
Sagebrush Good (>70%) D 55 2.00
Total 20.3
CURVE NUMBER 75
Approved Yoast Mine curve numbers are presented in Appendix 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.
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TR-36 13-12.1-74 Revised 08/07