PERMFILE130103

• Permit No: C1980001
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: 3.5 ROADS
• Media Type: D
• Archive: No

(unnumbered culverts). This same procedure was used to find the year of
• highest runoff into the Moffat Area sediment pond. The year of highest runoff
for the sediment pond can be found in the Sediment pond Section 9.6.1.
3.5.3.4 Peak Flow Determination for Culverts in East Ridge (E),
Center Ridge (C), Skyline (SK) and Tipple Area (TA)
The drainage areas of these culverts will not be disturbed by mining or
reclamation. Therefore the condition of these drainage areas will remain the
same far the life of the culverts. Table 3.5-2 lists the design criteria used
to determine the peak flow of the culverts. The drainage areas for all
culverts with the exception of the Tipple Area culverts can be found in
Exhibit 3.5-22. The Tipple drainage areas can be found in Exhibit 4.6-21.
Appendix 3.5-A lists the results of the computer simulations for the drainage
areas of the culverts.
Drainage areas for Tipple Area culverts TA-11 through TA-18 are 'not
listed Table 3.5-2 nor were computer simulations performed on these culverts.
All of these culverts were existing at the time of the original permit
• submitt
ur
ose al and only provide drainage in
of these culverts is to
rev
nt and about the loadout facility. The
wate
"standin
" fr
i
t
h
p
p p
e g
r
om occurr
ng a
e
t
loadout facility in low lying areas. It was not considered necessary to
perform computer simulations on these culverts because none of the culverts
service a drainage area greater than 2.5 acres and previous computer
simulations on drainages of similar or larger size (i.e., TA-1 and TA-8) did
not provide peak flows sufficient to suggest that the existing culverts may
not to adequate.
3.5.3.5 Culvert Design
Using the computer generated peak flow rates, the culverts were sized
from Figure 4-18 of the publication "Handbook of Steel Drainage and Highway
Construction Products", 1977. They were sized for zero head and inlet
control. Table 3.5-3 lists the peak flow r tes, size required for each
culvert, the culvert size existing or to be used, and the appendices where the
peak flow rates were determined. It should be noted that no runoff was
• 3.5-Sb May 14,1993