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

SENECA II-W
Channel PM-2 System
HYDROLOGIC INPUT PARAMETERS

SEDCAD 4
Channel PM-3
Watershed ID -Structure 7 - SWS1
Watershed Area:
11.7
Curve Number:
VEGETATION HYDROLOGIC CURVE AREA
WATERSHED TYPE COVER SOIL GROUP NUMBER (acres)
Aspen/Mountain Shrub Good (>70%) B 30 5.73
Sagebrush Good (>70%) C 47 5.98
Total 11.71
CURVE NUMBER 39
SEDCAD 4
Channel PM-3
Watershed ID -Structure 7 - SWS2
Watershed Area:
76.6
Curve Number: Postmine Conditions
VEGETATION HYDROLOGIC CURVE AREA
WATERSHED TYPE COVER SOIL GROUP NUMBER (acres)
Aspen/Mountain Shrub Good (>70%) B 30 2.82
Sagebrush Good (>70%) C 47 1.40
Reclaimed Good (>70%) C 71 72.40
Total 76.62
CURVE NUMBER 69
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.
TR-59
20-1.167
Revised 08/07