2009-08-20_PERMIT FILE - C1980001A

• Permit No: C1980001A
• IBM Index Class Name: Permit File
• Doc Date: 8/20/2009
• Section_Exhibit Name: 4.6 Hydrologic Balance Control Plan
• Media Type: D
• Archive: Yes

occurring drainage divide between Oak Creek and
• Trout Creek.
Northern boundary- This boundary will be established by grading and
sloping to provide a drainage break between the
coal stockpile area and the maintenance shop.
Western boundary- This boundary will be established by the grading
and sloping of the area from the truck/storage
shed to the centerline between the shed and
maintenance shop as previously mentioned. The
area to the west of the storage shed is the west
Ridge haulroad with drainage control provided by
the haulroad ditch.
J1, B2,S1,SW1, J1, B2,S1,SW2; and J1, B1, S1, SW3:
Eastern Boundary- The boundary for these subwatersheds is
established by the natural topographic drainage
divide between Oak Creek and Trout Creek.
Additionally, a safety berm is also used in this
location, although its primary function is to
provide protection for equipment used around the
Coal stockpile area. The safety berm is
maintained at a minimum height of two feet.
Other boundaries- All of the other external boundaries surrounding
the combined subwatersheds are established by
ditches, except for the southwestern boundary
subwatershed J1,B1,S1,SW3. This boundary is
established by a natural topographic high point
on the west Ridge haulroad.
The subwatershed area serviced by Ditch FD-4 contains underground
storage tanks requiring a delay in the construction of FD-9 until the
underground tanks are removed and new above ground tanks are installed. As a
result, Ditch FD-3 has been sized to pass the peak flow of runoff from the
subwatershed serviced by Ditch FD-4 as well as the peak flow from Culvert FC-
1. The lower portion of Ditch FD-5 has been designed to pass the peak flow
from the upper portion of Ditch FD-5 and Ditch FD-4 in anticipation of
completion of Ditch FD-4.
• 4.6-39b May 20, 1993