2022-10-17_PERMIT FILE - C1981019A ‎(12)‎

• Permit No: C1981019A
• IBM Index Class Name: Permit File
• Doc Date: 10/17/2022
• Doc Name: Upper and Lower Section 3 Ponds
• Section_Exhibit Name: Exhibit 07 Item 14 Appendix 7-14S3
• Media Type: D
• Archive: Yes

Exh. 7-14S3-2 Revision Date: 8/15/22
Revision No.: TR-155
Streeter & Buckskin Permanent Post Mine Channels

The Section 3 Pond watershed is comprised of two post-mining channels. The main channel is
the Streeter Ditch, which will convey post mining surface water flows to the Upper and Lower
Section 3 Ponds. Buckskin Ditch is a tributary to the Streeter Ditch. The locations of both
channels are presented on Map 12 and Figure Exh. 7-14S3-2, and the channel profiles are
presented on Map 33.

Both channels have been designed in accordance with Rule 4.05.4(2)(b) for the 100-year, 24-
hour storm event as the watershed reporting to the Upper and Lower Section 3 Ponds is greater
than one square mile.

A SEDCADTM model has been included which evaluates the peak flow and total runoff volume
for each of the channel segments for the 100 year, 24-hour storm event. The channel
configurations for the Streeter and Buckskin Ditches are summarized below.

Streeter Ditch
Station Peak Flow
(CFS)
Average
Slope (%) Channel Type Side Slopes Erosion
Protection
Station 0+00 to
SD-1 104.12 4.7 Trapezoidal 15’
bottom 3H:1V Riprap,
D50 = 6”
SD-1 to SD-2 109.89 4.4 Trapezoidal 15’
bottom 3H:1V Riprap,
D50 = 9”
SD-2 to SD-3 111.97 2.7 Trapezoidal 15’
bottom 3H:1V Vegetation
SD-3 to
Confluence with
Buckskin Ditch
104.21 2.1 Trapezoidal 15’
bottom 3H:1V Vegetation
Confluence of
Buckskin Ditch to
Station 101+46
81.98 2.6 Trapezoidal 15’
bottom 3H:1V Vegetation

Buckskin Ditch
Station
Peak
Flow
(CFS)
Average
Slope (%)
Channel
Type
Side
Slopes
Erosion
Protection
Station 0+00
to 35+00 37.48 4.0 Trapezoidal
12’ bottom 3H:1V Vegetation