2005-06-15_PERMIT FILE - C1992081A

• Permit No: C1992081A
• IBM Index Class Name: Permit File
• Doc Date: 6/15/2005
• Doc Name: Sediment Control and Pond Designs
• Section_Exhibit Name: Tab 12 Appendix 12-1
• Media Type: D
• Archive: Yes

CN: curve number (CN) design criteria aze from existing permit information;
Procedures jor Determining Peak Flows in Colorado (SCS, 1980) was
utilized to determine runoff design criteria for the following conditions.
Disturbed -facilities area
Soil type:
Ground cover
Cover type:
CN:
SedimentoloQV: R-Factor:
K-Factor:
LS Factor:
C Factor:
P Factor:
C
bare, poor ground cover
none
89
10 (taken from Figure 8A.6 in Haan, Barfield, and
Hayes, 1994, after Renard et al., 1993).
0.25 (from Appendix 12-2 of existing permit)
digitized from Exhibit 12-2
1.0 (baze soil, packed under construction conditions)
1.0
Grain size analysis: from Appendix 12-2 of existing permit
Pond Desien: from Exhibit 12-3 of existing permit
Waterman headgate invert elevation is 6,397.0 feet; 24-inch drop inlet
spillway (principal) elevation is 6,400.0 feet, the 12-inch straight pipe
spillway (emergency) elevation is 6401.5 feet.
The Waterman headgate allows HGTI to control the pond water elevation to
assure that there is sufficient storage space to meet the intentions of Rule
4.05.9(2)(b).
Initial pool elevation in SEDCAD demonstration set at 6,400.0 feet.

TR-06 12-18.2 Revised OS/OS