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-19
Watershed ID -Structure 6 - SWS1
Watershed Area: 9.1
Curve Number:
HYDROLOGIC CURVE AREA
WATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER (acres)
Reclaimed Fair (30% - 70%) B 71 4.5
Reclaimed Topsoiled, No Vegetation B 86 1.7
Aspen/Mountain Shrub Good (>70%) C 41 2.9
Total 9.1
CURVE NUMBER 64
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.
SEDCAD 4
Channel YPM-19
Watershed ID -Structure 6 - SWS1
Watershed Area: 9.1
Sedimentology: k Factor and Control Factor:
HYDROLOGIC CONTROL AREA
WATERSHED TYPE VEGETATION COVER SOIL GROUP k FACTOR FACTOR (acres)
Reclaimed Fair (30% - 70%) B 0.16 0.043 4.5
Reclaimed Topsoiled, No Vegetation B 0.16 1.0 1.7
Aspen/Mountain Brush Good (>70%) C 0.37 0.042 2.9
Total 9.1
0.23 0.22
Undisturbed vegetation information taken from Exhibit 10-1, Premining Vegetation Map. Hydrologic soil group values
based on soil types which were taken from Exhibit 9-1, Soils Type and Soils Salvage Map. Disturbed area vegetation
information (Reclaimed: vegetated, fair [30% - 70%]; or, topsoiled, no vegetation) taken from 2006 Annual Reclamation
Chronological Seeding Map (Yoast Mine 2006 Annual Reclamation Report). Field observations as of June 2007 indicate
areas seeded in 2006 display good stand establishment and growth. Approved Yoast Mine "k" Factor and Control Factor
values are presented in Appendix 13-12, Postmining Drainage and Sediment Control, Tables 13-12.2 and 13-12.3,
respectively.
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TR-36 13-12.1-70 Revised 08/07