2010-10-07_PERMIT FILE - C1994082 ‎(2)‎

• Permit No: C1994082
• IBM Index Class Name: Permit File
• Doc Date: 10/7/2010
• Doc Name: YPM-9 to YPM-24, Dragline Deadhead Route Postmine Channel
• Section_Exhibit Name: Tab 13 Attachment 13-12 Appendix 13-12.3 Part 2
• Media Type: D
• Archive: No

YOAST MINE
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Postmine Channel Designs -Channel YPM-11
HYDROLOGIC INPUT PARAMETERS
SEDCAD 4
Structure 11 -SWS1
Watershed ID: Channel YPM-22
~Natershed Area: 15.8
Curve Number:
HYDROLOGIC CURVE
WATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER AREA (acres)
Aspen/Mountain Brush Good (>70%) C 41 4.66
Aspen/Mountain Brush Good (>70%) D 48 3.71
Sagebrush Good (>70%) C 47 1.62
Fair (30% - 70%) B 71 5.8
Reclaimed
Total 15'8
CURVE NUMBER 54
SEDCAD4
Structure 12 - SWS2
Watershed ID: Channel YPM-22
Watershed Area: 1.4
Curve Number:
HYDROLOGIC CURVE
WATERSHED TYPE VEGETATION COVER SOIL GROUF NUMBER AREA (acres)
Fair {30% - 70%) B 71 1.4
Reciaimed
Total 1.4
CURVE NUMBER 71
Vegetation cover conditions presented in Tab 10, Vegetation, Attachment 10-1, 1990/1992 Vegetation Baseline Repon,
Yoast 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, Sail Conservation Service, 1986.

TR-37
13-12.3-141 I
Revised 02/08