2013-12-17_PERMIT FILE - C1992081 ‎(19)‎

• Permit No: C1992081
• IBM Index Class Name: Permit File
• Doc Date: 12/17/2013
• Section_Exhibit Name: Tab 12 Facilities
• Media Type: D
• Archive: No

A 12 -inch diameter culvert was installed above the existing 24 -inch diameter culvert
spillway. Certification reports for this pond modification are presented in Appendix 12 -1A,
Pond Certifications.
Capacity tables for the two ponds are shown on Exhibit 12 -3, Truck Loop Pondl, and Exhibit
12 -4, Rail Loop Pond2. Per Exhibit 12 -3, the Truck Loop Pond has an as-built storage
capacity of 1.11 acre -feet at the principal spillway elevation (24 -inch drop inlet pipe), and
1.56 acre -feet at the invert of the emergency spillway (12 -inch straight pipe). As shown on
Exhibit 12 -4, the Rail Loop Pond has an as -built storage capacity of 1.69 acre -feet at the
invert of the combination principal and emergency (trapezoidal) spillway.
Area -stage information was compiled from an October 1992 aerial photography survey, a
1991 sediment survey and, for the Rail Loop Pond only, a 1997 as-built survey. Certification
of these as-built drawings is limited to storage capacities only and is not intended to verify
design and/or construction standards. Design and construction certifications were completed
by the previous operator /owner and are referenced above.
Truck Loop Pond: Appendix 12 -1, Sediment Control and Pond Design, presents a
SEDCAD4 modeling demonstration that shows the existing storage capacity (0.97 acre -feet)
is adequate to detain runoff from the truck dump watershed area generated by the 10 -year,
24 -hour storm event and, that the as -built pond configuration meets the requirements of
Rules 4.05.6 and 4.05.9.
Rail Loop Pond: Appendix 12 -1 also contains a SEDCAD4 modeling demonstration that
shows the existing configuration (1.91 acre -feet of storage) is sufficient to detain runoff from
the 10 -year, 24 -hour storm event and that the as-built pond configuration meets the
requirements of Rules4.05.6 and 4.05.9. Note that there is a slight discrepancy between the
"as- built" storage capacity (1.69 ac -ft) and the SEDCAD model capacity (1.91 ac -ft). This is
due to slight differences in how the surveyed as -built values versus the SEDCAD generated
values were calculated. Both instances show there is sufficient capacity to detain runoff from
the 10 -year, 24 -hour storm event.
Small Area Exemptions
Topsoil Stockpiles: There are three topsoil stockpiles (TS -1, portion of TS -2 and TS -3)
within the Loadout area and six topsoil stockpiles (A, C, D, E, F and G) and one temporary
waste stockpile (TWS) associated with the TAHR. The locations of these stockpiles are
shown on Exhibit 9 -2, Soil Types & Topsoil Salvage Map (TAHR Corridor) and Exhibit 12-
2, Surface Water Control Plan Map (Facility Area). In order to demonstrate that these piles
meet the intention of Rule 4.05.2(3), SEDCAD+ analyses were conducted. These
demonstrations and discussions are presented in Appendix 12 -2 Small Area Exemptions.
Topsoil stockpile TS -1 and apportion of TS -2 have been replaced on the reclaimed portion of
the facilities area. The status of the remaining stockpiles has not changed since their
construction in the 1970's and 1980's except for the establishment of vegetative cover. Due
to the shallow slopes existing well established vegetative cover, and small drainage areas
none of the stockpiles exhibit a soil loss through sediment erosion. Consequently, the topsoil
TR -10 3 Revised 02/13