2007-12-17_PERMIT FILE - C1981020A ‎(6)‎

• Permit No: C1981020A
• IBM Index Class Name: Permit File
• Doc Date: 12/17/2007
• Section_Exhibit Name: Appendix M‎(vii)‎ to M‎(viii)‎ Hydrologic Data
• Media Type: D
• Archive: Yes

Appendix M(vii)
} Munger Canyon Mine
Hydrologic Calculations - AS CONSTRUCTED
Surface Water Controls
Coal Mine Waste Bank/Refuse Pile
STORM EVENTS
10 YEAR 24 HOUR EVENT
25 YEAR 24 HOUR EVENT
100 YEAR 24 HOUR EVENT
1.5 INCHES
1.9 INCHES
2.3 INCHES
The pond sizing calculations presented below are calculated based
on the manual -Procedures for Determining Peak Flows in
Colorado -published by the Soil Gonservation Service dated
March 1984.
Ditch sizing calculations are prepared using SEDCAD"" 4
The upland run-off areas are shown on Figure 2.2.6 Waste Disposal Site,
Plan.
The vegetation study for the mine is located in Volume I
Section 4.8 beginning on page 4-90. The vegetation type
in the foundation area of the refuse pile is Big Sagebrush
Shrubland. The vegetation type in the upland area is
Juniper Woodland, ref. Figure 4.8-1.
The major soil type in the foundation area of the refuse pile is
Rivra Loam Variant. The soil type in the upland area is
Torriorthents rock outcrop complex, ref Figure 4.7-1.
Disturbed Area
Herbaceous-Mixture of grass, weeds
Hydrologic Condition Poor
Soil Type -Rivera Loam Variant A
Curve Number 80
Table 2-2d-Runoff curve numbers for grid and semiarid rangelands
Upland Area
Cover
Juniper Woodland affected area
Vegetative Cover % 43.3
Litter % 24.0
Ground Cover % 67.3 Table 4.8-13
TR-22 M(vii)-2 03/07