PERMFILE63825

• Permit No: C1981035A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: MODIFICATION A
• Section_Exhibit Name: APPENDIX 8 HYDROLOGIC DESIGNS
• Media Type: D
• Archive: Yes

• Table of Contents
1. Scope and Purpose ................................................................................... 1
2. Mine Drainage Plan ................................................................................... 1
2.1 Diversion of Uncontaminated Runoff ....................................................... 1
2.2 Treatment of Yard Runoff ...................................................................... 2
3. Drainage Basin Characteristics .................................................................... 3
3.1 Basin Geometry and Soils ..................................................................... 3
3.2 SCS Curve Number .............................................................................. 3
4. Hydrology ................................................................................................ 5
4.1 West Hillside Area ................................................................................ 5
4.2 Peak Discharges and Volumes ............................................................... 6
5. Drainage Structures .................................................................................. 6
5.1 Pipes and Channels ............................................................................. 6
5.2 Yard Drainage Routed to Ponds ............................................................. 7
5.3 Drainage Structure Summary ................................................................. 7
5.4 Rip-rap Design for the Eastside Drainage Channel ................................... 9
• 8. Sediment Ponds .................. 10
................................................................... .
6.1 Hydrology ............................................................................................ 10
6.2 Watershed Sediment Yield .................................................................... 12
6.3 Pond Geometry ......................................................................:............. 13
6.4 Outlet Works and Trash Rack ................................................................ 13
7. Topsoil Storage Pile Drainage .................................................................... 14

January 1998