PERMFILE127218

• Permit No: C1980005A
• IBM Index Class Name: Permit File
• Doc Date: 9/28/2007
• Doc Name: 10-Year, 24 Hour SEDCAD Modeling
• Section_Exhibit Name: Tab 07 Appendix 7-6c.1 Addendum 7.6-1A
• Media Type: D
• Archive: Yes

Seneca II Mine
Pond 004
HYDROLOGIC INPUT PARAMETERS
SEDCAD 4
WATERSHED ID
Structure 2 - SWS1
Subwatershed -Channel PM-17 Upper
Watershed Area:
41.8
Curve Number:
HYDROLOGIC CURVE AREA
WATERSHED TYPE GROUND COVER SOIL GROUP NUMBER (acres)
Reclaim >3 years Good (>70%) B 62 41.81
Total 41.8
CURVE NUMBER 62
Approved Seneca II Mine curve number (CN) values are presented in Appendix 7-12, Postiming Drainage
Control. Values were adapted from Urban Hydrology for Small Watersheds, Technical Release No. 55 (TR-
55), Soil Conservation Service, 1986.
SEDCAD 4
WATERSHED ID
Structure 2 - SWS1
Subwatershed -Channel PM-17 Upper
Watershed Area:
41.8
Sedimentology: k Factor and Control Factor
VEGETATION HYDROLOGIC k CONTROL AREA
WATERSHED TYPE COVER SOIL GROUP FACTOR FACTOR (acres)
Reclaimed Good (>70%) B 0.16 0.043 41.81
Total 41.8
0.16 0.043
The soil erodibility factor, "k-Factor", values were determined based on Seneca II soil survey information (see Tab 9, Exhibit 9~
1, Soil Type and Sampling Locations, and Attachment 9-6) as presented in Soils of Colorado, Loss Factors and Erodibility,
Soil Conservation Service, 1983.
The Control Factor values were adapted from the Yoast and Seneca II-W permit application packages. These values are
presented in each permit in the Drainage and Sediment Control Plan attachment, which is located in Tab 13 of the respective
permit documents. The values are based on Renard, et al. (Renard, K.G., Foster, G.R., Weesies, G.A., McCool, D.K., and
D.C. Yoder, coordinators, 1996. Predicting Soil Erosion by Water. A Guide to Convemtion Planning with the Revised
Universal Soi/Loss Equation (RUBLE). Agricultural Handbook 703. U.S. Department of Agriculture.
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TR-42 7-6c.1 A-20 Revised 09/07