_PERMIT FILE - C1981008A ‎(13)‎

• Permit No: C1981008A
• IBM Index Class Name: PERMIT FILE
• Doc Name: Sedimentation Pond 004
• Section_Exhibit Name: Tab 13 Attachment D
• Media Type: D
• Archive: Yes

tc = [11.9(L)3]0.385
H
where:
L = hydraulic length = 0.186 miles
H = watershed height = 95 ft.
tc = 0.064 hr.
SEDIMENTOLOGY
The SEDIMOT II computer program was also utilized to calculate the
sedimentology of each watershed using the modified universal soil loss
equation (MUSLE) . Using a density of 87 lbs/cubic foot, 65.46 tons or
0.035 ac-ft. of sediment will be deposited in this pond as the result of
a 10-year, 24-hour storm. A total of 0.11 ac-ft. or 3.1 MUSLE 10-year,
24-hour storm event equivalent storage is provided for sediment yield.
Peabody will restore adequate sediment storage to the pond when the
available sediment storage becomes 0.035 ac-ft. or less.
Particle Size Distributions
The particle size distribution for this sediment pond was taken from
Simons, Li and Associates (Design of Sediment Control Measures for Small
Areas in Surface Coal Mining) . This distribution is representative of a
sandy loam soil similar to those described in Tab 9 of the current Nucla
Mine Plan. The inputted soil particle distribution is as follows:
Particle Size Percent Finer
2.0000 100.0
1.0000 100.0
0.1000 85.0
0.0500 80.0
0.0020 20.0
0.0001 0.0
The specific gravity of the soil and the submerged bulk specific gravity
were estimated based on the reference cited above and are 2.5 and 1.25,
respectively.
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