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

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YOAST MINE
Fostmine Channel Designs -Channel YPM-11
HYDROLOGIC INPUT PARAiNETERS
WATERSHED ID
Structure 5 - SWS1
Watershed - W-20 (YPM-20)
V~(atershed Area: 17.2
Curve Number:
HYDROLOGIC CURVE
WATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER AREA (acres)
Aspen/h9cuntain Brush Good (>70%) B 30 0.81
AspenlMountain Brush Good (>70%) C 41 3.42
Aspen/Mountain Brush Good (>70%) D 48 3.05
Herbaceous Goad (>70%) C 74 1.32
Sagebrush Good (>70%) C 47 0.81
Sagebrush Good (>70%) D 55 0.73
Fair (30% - 70%) B 71 7.09
Reclaimed
Total 17'2
CURVE NUMBER 57
Vegetation cover conditions presented in Tab 10, Vegetation, Attachment 10-1, 1990/1992 Vegetation
Baseline Report, 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, Soil Conservation
Service, 1986.
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TR-37 13-12.3-141 C Revised 02/08