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
Pond12A
Watershed ID -Structure 11 - SWS1
Watershed Area: 3.8
Curve Number: Unvegetated Watershed
HYDROLOGIC CURVE AREA
WATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER (acres)
Reclaimed Topsoiled, No Vegetation B 86 3.2
Aspen/Mountain Shrub Good (>70%) C 41 0.6
Total 3.8
CURVE NUMBER 79
SEDCAD 4
Pond 12A
Watershed ID -Structure 11 - SWS2
Watershed Area: 1.5
Pond surface
Curve Number:
HYDROLOGIC CURVE AREA
WATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER (acres)
Pond Water surface N/A 100 1.5
Total 1.5
CURVE NUMBER 100
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.
TR-36 13-12.1-77 Revised 08/07