2007-10-30_PERMIT FILE - C1982057A

• Permit No: C1982057A
• IBM Index Class Name: Permit File
• Doc Date: 10/30/2007
• Section_Exhibit Name: Tab 20 Attachment 20-1 Part 2
• Media Type: D
• Archive: Yes

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TR-59
SENECA II-W
Channel PM-2 System
HYDROLOGIC INPUT PARAMETERS
SEDCAD 4
Channel PM-6
Watershed ID -Structure 5 - SWS1
Watershed Area:
15.5
Curve Number: Postmine Conditions
VEGETATION HYDROLOGIC CURVE AREA
WATERSHED TYPE COVER SOIL GROUP NUMBER (acres)
Aspen/Mountain Shrub Good (>70%) B 30 10.19
Sagebrush Good (>70%) C 47 1.40
Reclaimed Good (>70%) C 71 3.90
Total 15.48
CURVE NUMBER 42
SEDCAD 4
Channel PM-6
Watershed ID -Structure 5 - SWS2
Watershed Area:
38.1
Curve Number: Postmine Conditions
VEGETATION HYDROLOGIC CURVE AREA
WATERSHED TYPE COVER SOIL GROUP NUMBER (acres)
Sagebrush Good (>70%) C 47 8.09
Aspen/Mountain Shrub Good (>70%) B 30 18.90
Reclaimed Good (>70%) C 71 11.08
Total 38.07
CURVE NUMBER 46
Approved II-W Mine curve numbers are presented in Appendix 13-5B, Postmining Drainage and
Sediment Control, Table 1, Seneca II-W (South Expansion Area) Curve Numbers. Values were
adapted from Urban Hydrology for Small Watersheds, Technical Release No. 55, Soil Conservation
Service, 1986.
20-1.165
Revised 05/07