2023-12-14_PERMIT FILE - C1981019 ‎(13)‎

• Permit No: C1981019
• IBM Index Class Name: Permit File
• Doc Date: 12/14/2023
• Doc Name: West Taylor Pond and Channels
• Section_Exhibit Name: Exhibit 07 Item 20 Part B -ST
• Media Type: D
• Archive: No

Exh. 7-20B-3 Revision Date: 10/23/23
Revision No.: TR-161

West Fork Taylor Ditch
Station Peak Flow
(CFS)
Average
Slope (%)
Channel
Type
Side
Slopes
Minimum
Depth
(Feet)
Erosion
Protection
Station 0+00 to
WFSP-1 46.17 26 Trapezoidal
12’ bottom 3H:1V 4.0 Riprap,
D50 = 15”
WFSP-1 to
WFSP-2 71.02 1.3 Trapezoidal
12’ bottom 3H:1V 4.0 Vegetation
WFSP-2 to
Station 85+00 68.97 10.2 Trapezoidal
12’ bottom 3H:1V 4.0 Vegetation

Tributary Ditches

The six post mine tributaries channels (Trib’s 1 through 6) will be constructed to break up long
continuous slopes and minimize erosion in the South Taylor reclamation areas. They will also
convey flow to the two primary channels. These six tributaries were modeled in accordance with
Rule 4.05.3(3) for the 10-year 24-hour event.

A very small portion of Trib 1 flows over a permanent fill, which in accordance with Rule
4.09.2(7) makes the appropriate storm event for this small portion of channel the 100-year, 24
hour storm event. Since it is minor portion of the channel flows over permanent fill, Trib 1 is
modeled to the 10-year, 24-hour storm event.

A summary of the configurations for each tributary channel is provided on the table below.

Post Mine Tributary Channels
Tribuary Name
Peak
Flow
(CFS)
Average
Slope (%)
Channel
Type
Side
Slopes
Minimum
Depth
(Feet)
Erosion
Protection
Trib 1 12.49 5.0 Trapezoidal
6’ bottom 3H:1V 3.0 Vegetation
Trib 2 5.57 11.0 Trapezoidal
6’ bottom 3H:1V 3.0 Vegetation
Trib 3 5.51 11.0 Trapezoidal
6’ bottom 3H:1V 3.0 Vegetation
Trib 4 0.11 16.0 Trapezoidal
6’ bottom 3H:1V 3.0 Vegetation
Trib 5 0.11 4.0 Trapezoidal
6’ bottom 3H:1V 3.0 Vegetation
Trib 6 0.05 6.0 Trapezoidal
6’ bottom 3H:1V 3.0 Vegetation
Trib 7 0.12 7.0 Trapezoidal
6’ bottom 3H:1V 3.0 Vegetation