2006-08-02_PERMIT FILE - C1980007 ‎(8)‎

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 8/2/2006
• Doc Name: Hydrologic/Hydraulic Analysis for Roadway Drainage
• Section_Exhibit Name: Exhibit 75 SGARE Appendix G Report to Appendix E
• Media Type: D
• Archive: No

Table 2 Routing Characteristics
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From Sub-Outlet To Sub-Outlet Routin Len th Avera a Slo a Note

1 2 1,725 11.01 Channel
2 3 425 11.91 Trunk Line 2
4 3 29 31.14 Cross Drain 9
3 5 220 11.51 Trunk Line 2
5 6 976 9.16 Trunk Line 1
6 7 385 7.70 Channel
8 7 40 15.00 Cross Drain 6
7 9 420 8.11 Channel
9 10 106 5.94 Cross Culvert 3
10 II 105 6.67 Cross Culvert 2
11 12 240 7.06 Channel
13 12 67 16.42 Cross Drain 5
12 14 840 7.62 Channel
15 14 96 26.04 Cross Drain 4
14 16 540 8.96 Channel
17 16 34 20.59 Cross Drain 2
16 18 900 6.70 Channel
18 19 80 5.24 Channel
20 19 30 3.33 Cross Drain 1
19 21 1,090 7.50 Channel
21 0 100 10.50 Cross Culvert 1
Unit Hydroerauh Response Shape
The unit hydrograph methodology with a double triangle dimensionless unit hydrograph shape
(DUHS) is used in SEDCAD 4 (Warner, 2004). Three different types of DLTI-IS can be chosen to
provide the model user with the opportunity to obtain a refined prediction of the storm
hydrograph. The slow DUHS that was developed for heavily forested areas with thick ground
residue covering greater than 75% of the surface was selected in the modeling because it best
described the site conditions among the three types of DUHS. For a detailed site description and
the vegetation cover distribution data, please refer to the USDA Forest Service Report on Service
Trip to Sylvester Gulch (Johnston, 2004) that is included in Appendix C of this study and the
Exhibit 32A of the West Elk Mine permit application package (Savage and Savage, Inc., 1996).
Sub-Watershed Sedimentolo yg Inyut
A set of sediment-related factors -soil erodibility, representative slope length, representative
slope, type of soil cover and control practices -were selected to each sub-watershed based on the
site conditions and the gradation test results.
Culvert Da[a
Locations, lengths, diameters, and inlet and outlet elevations for Trunk lines, cross culverts, and
cross drains were initially selected based on the site conditions and a preliminary design, and
adjusted in accordance with [he requirements of Forest Service, model results and later designs.
• This procedure was repeated several times to obtain the final design data.
Sunrise Engineering, Inc.
Sylvester Gulch Access Road
Hydrologic /Hydraulic Analyses for Roadway Drainage