2002-05-13_PERMIT FILE - C1981041 (16)

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APPENDIX 13-3 • ALTERNATE DRAINAGE AREAS RUNOFF CALCULATIONS REFERENCE: Procedures for Determining Peak Flow in Colorado, S.C.S. March 1980. Overland Conveyor -Transfer 2-3 Area: 6.15 Acres CN: 76 (Green River (C), 20% dirt road, 80% woods in fair conditions) Runoff: 0.15"/12 x 6.15 Acres = 0.077 Acre-Ft. Powder & Cap Magazine Area: 0.023 Acres CN: 89 {Lazear {D), dirt road) Runoff: 0.55112 x 0.023 Acres = 0.001 Acre-Ft. Overland Conveyor -Coal Canyon to Rail Loop Area: 16.50 Acres CN: 78 (Green River (C), Sage-grass 20% cover) • Runoff: 0.19"/12 x 16.50 Acres = 0.261 Acre-Ft. Overland Conveyor -East End of Tube over River Area: 0.15 Acres CN: 83 (50% Green River (C), Sage-grass 20% cover, 50% dirt road) Runoff: 0.32"/12 x 0.15 Acres = 0.004 Acre-Ft. South Fan -Bench and Topsoil Stockpile Area: 0.455 Acres CN: 87 (Lazear (D), 30% Sage-grass 20% cover, 70% dirt road) Runoff: 0.47"112 x .455 Acres = 0.018 Acre-Ft. CRDA No. 1 -Topsoil Piles 5 & 6 Area: 2.1 Acres CN: 86 (Soil group B, dirt fallow) Runoff: 0.43"/12 x 2.1 Acres = .075 Acre-Ft. CRDA No. 2 -Stockpiles Area: 2.10 Acres CN: 83 (Lazear (D), Sage-grass 20% cover) Runoff: 0.32"/12 x 2.10 Acres = 0.056 Acre-Ft. • 13-3-1 (New 3/1/96)