2011-12-01_APPLICATION CORRESPONDENCE - C2010089 ‎(2)‎

• Permit No: C2010089
• IBM Index Class Name: Application Correspondence
• Doc Date: 12/1/2011
• Doc Name: Preliminary Adequacy Review No. 2
• From: Western Fuels Association
• To: DRMS
• Email Name: MLT
• Email Name: SB1
• Media Type: D
• Archive: No

However, the response to question number 12 -B of this section may require another
review if the elevations of the primary discharge pipes are raised.
Response — DRMS may wish to make another review in light of WFC's response to 12b
below.
12. DRMS: The Division has no further concerns with this question. In the renamed Appendix
2.05.3(4) -1 of the May 26, 2011 submittal, WFC stated that the gated primary discharge
pond inlets would minimize short circuiting. WFC further explained that location
constraints prohibited redesigning the ponds. The Division, however, has additional
questions concerning sediment in the ponds.
a) In the last sentence of the 3` complete paragraph on page 4 of the Arcadis report in
Appendix 2.05.3(4) -1, the sediment storage elevations listed for the three sediment
ponds don't match the sediment storage elevations presented in Table 3 on page 5.
Please revise.
Response — The discrepancies between the last sentence on page 4 and Table 3 on page 5
has been corrected by revising the text.
b) Referring to Table 3 of the Arcadis report in Appendix 2.05.3(4) -1, the invert of the
primary discharge pipe elevation for each sediment pond is located just above the
maximum sediment storage elevation. The Division is concerned that the sediment
ponds may have sediment discharge problems due to this small elevation difference.
The Sedcad manual, on page 64, recommends a minimum 2 foot difference between the
top of the sediment level and the primary pipe invert. If the release is slow, 0.5 feet to
1.0 feet can be used. Please consider increasing the height between the top of the
sediment storage level and the invert of the primary discharge pipe, allowing for the
requirement mentioned in question number 9 of this section that the pond capacity
between the primary discharge pipe and the emergency spillway must contain the runoff
volume from a 10 year -24 hour event.
Response — Pipe inverts have been revised as suggested and pond volumes re- evaluated.
13. DRMS: The Division has no further concerns with this question. Figures 1 -4 were revised
in the May 26, 2011 submittal. However, the Division has two additional requests.
a) It does not appear that the primary and emergency discharge structures for the three
sediment ponds are shown on Map 2.05.3(3) -1. Please add these structures to the map
since they are part of the surface water hydrology.
Response — Map 2.05.3(3) -1 Surface Water Hydrology has now been labeled as Map
2.05.3(4) -1 Surface Water Hydrology. The primary and secondary discharge structures
for the three ponds have been added on Map 2.05.3(4) -1.
b) In Table 2 on page 4 of the Arcadis report in Appendix 2.05.3(4) -1, a primary discharge
pipe length of 247 feet is given for sediment pond NHN -002. However, referring to
Figure 3 of the same report, the pipe length appears to be about 60 feet. Please clarify.
Response — Expanded the footprint of NHN002 and re- designed the primary discharge
pipe. It is now 75 feet long.
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