2008-12-04_PERMIT FILE - C1994082A ‎(16)‎

• Permit No: C1994082A
• IBM Index Class Name: Permit File
• Doc Date: 12/4/2008
• 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: Yes

YOAST POSTMINE CHANNEL 12
HYDROLOGIC INPUT PARAMETERS
SEDCAD4
WATERSHED ID
Structure 1 - SWS2
Channel YPM-13 Watershed
Watershed Area: 26.3
Curve Number:
HYDROLOGIC SOIL CURVE
WATERSHED TYPE VEGETATION COVER GROUP NUMBER AREA (acres)
Aspen/Mountain Brush Fair (30% - 70%) D 63 0.2
Reclaimed Fair (30% - 70%) B 71 26.1
Total 26.3
CURVE NUMBER 71
Vegetation cover conditions for undisturbed areas presented in Tab 10, Vegetation, Attachment 10-1,
1990/1992 Vegetation Baseline Report, Yoast Study Area (ESCO Associates, 1993). Approved Yost 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.
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TR-37 13-12.3-1421 Revised OS/08