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

.~
•

Yoast Nline
Pos#mine Channel Design
HYDROLOGIC I~lP1lT PARAMETERS
SEDCAD 4
Channel YPM-6-3
OPTION 2
Watershed ID -Structure 12 - SWS1
Watershed Area: 25.7
Curve Number:
HYDROLOGIC CURVE AREA
!~lATERSHED TYPE VEGETATION COVER SOIL GROUP NUMBER (acres)
Reclaimed Fair (30% - 70%) B 71 21.07
Aspen/Mountain Shrub Good (>70%) B 30 0.99
Steep Mountain Brush Fair (0% - 70%) D 73 1.80
Sagebrush Good (>70%) D 48 0.74
ebrush
li Sa
/Alk Good (>70%) D 85 1.10
g
a
W. Wheatgrass
Total 25'7
CURVE NUMBER 69
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 Sadiment Control ,Table 13-12.1. Values were adapted from Urban Hydro/ogy fcr Small
Watersheds, Technical Release No. 55, Sail Conservation Service, 1986.
Revised 02/08
TR-37 13-12.3-26A