PERMFILE56724

• Permit No: C1994082
• IBM Index Class Name: Permit File
• Doc Date: 9/27/2007
• Doc Name: 10-Year, 24 Hour SEDCAD Demonstration
• Section_Exhibit Name: Tab 13 Attachment 13-3A.2 Addendum 13-3A-A
• Media Type: D
• Archive: No

YOAST MINE
Pond 10 -Watershed W-20
HYDROLOGIC INPUT PARAMETERS
SEDCAD 4
WATERSHED ID
Structure 5 - SWS1
Watershed - W-20 (YPM-20)
Watershed Area:
17.0
Curve Number:
VEGETATION HYDROLOGIC CURVE AREA
WATERSHED TYPE COVER SOIL GROUP NUMBER acres
Aspen/Mountain Brush Good (>70%) C 41 5.58
Sagebrush Good (>70°h) C 47 1.54
Spoil Bare C 86 9.92
Total 17.0
CURVE NUMBER 68
Curve number (CN) values used are approved Yoast Mine values (see Table 13-12.1). Values
were adapted from Urban Hydrology for Small Watersheds, Technical Release No. 55 (TR-55) ,
Soil Conservation Service, 1986.
SEDCAD 4
WATERSHED ID
Structure 5 - SWS1
Watershed W-20 (YPM-20)
Watershed Area:
17.0
Sedimentology
k Factor and Control Factor:
VEGETATION HYDROLOGIC k CONTROL AREA
WATERSHED TYPE COVER SOIL GROUP FACTOR FACTOR acres
Aspen/Mountain Brush Good (>70%) C 0.37 0.042 5.58
Sagebrush Good (>70%) C 0.19 0.042 1.54
Spoil Bare C 0.16 1.0 9.92
Total 17.0
0.23 0.60
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TR-35 13-3A-A.24 Revised 08/07