2010-10-07_PERMIT FILE - C1994082

• Permit No: C1994082
• IBM Index Class Name: Permit File
• Doc Date: 10/7/2010
• Doc Name: Post Mining Channels SEDCAD Results/Channel YPM-1 to YPM-8
• Section_Exhibit Name: Tab 13 Attachment 13-12 Appendix 13-12.3
• Media Type: D
• Archive: No

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TR-37
Yoast Mine
Postmine Ctlanne! Design
~1YDROLOGIC INPUT PARAMI=TERS
SEDCAD 4
Channel YPM-6-1
Watershed ID -Structure 7 - SWS1
West side subwatershed
Watershed Area: 8.2
Curve Number:
HYDROLOGIC CURVE AREA
11~/ATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER (acres)
Reclaimed Fair (30% - 70%) B 71 1.54
Aspen/Mountain Shrub Good (>70%) B 30 2.13
en/Mountain Shrub
As Good (>70%) C 41 4.56
p
Total ~ 8.23
CURVE NUMBER ~
SEDCAD 4
Channel YPM-6-1
Watershed ID -Structure 7 - SWS2
East side subwatershed
4~Jatershed Area: 27.8
Curve Number:
HYDROLOGIC CURVE AREA
WATERSHED TYFE VEGETATION COVER SOIL GROUP NUMBER (acres)
Reclaimed Fair (30% - 70%) B 71 20.50
Aspen/Mountain Shrub Good (>70%) B 30 3.78
Aspen/Mountain Shrub Gocd (>70%) C 41 0.22
Sagebrush Good (>70%} 8 35 2.20
Sagebrush Good (>70%} C 47 1.12
Total 27.82
CURVE NUMBER 61
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.
13-12.3-22
Revised 02/08