2011-09-09_REVISION - M1981185 ‎(43)‎

• Permit No: M1981185
• IBM Index Class Name: REVISION
• Doc Date: 9/9/2011
• Doc Name: Response to Fifth Adequacy Letter
• From: R Squared, Inc.
• To: DRMS
• Type & Sequence: CN1
• Media Type: D
• Archive: No

Mr. Wallace H. Erickson
Response to August 22, 2011 Cazier Memorandum
September 9, 2011
Page 9
Attachment D -6, Augmentation Pond Work Plan
Adequacy Issue No. 12.
Page 3, Construction. The first bullet references Attachment D -6, Figure D -1 for
stormwater management controls. Neither Figure D -1 nor D -2 show any BMPs, nor can
the augmentation pond be considered a stormwater management control. Please provide
stormwater management control locations and type on Figure D -2.
Response to Adequacy Issue No. 12.
Wildcat is correcting the reference in the first bullet to Attachment D -6, Figure
D -2, and is submitting a revised Attachment D -6, Figure D -2 showing stormwater
management control locations and type. See Attachment 3. The augmentation pond is
not a stormwater management structure. Wattles will be installed during construction
and augmentation pond berms will be stabilized following completion. In addition, a
down gradient perimeter ditch and catch basin will be installed to collect and divert
stormwater and spring melt runoff water through a catchment basin.
Adequacy Issue No. 13.
Page 3, Construction. Item 3 discusses a two -foot (minimum) keyway and a liner for the
pond. Neither of these is shown in Figure D -1 or D -2. Please provide enough detail to
demonstrate how the liner is installed and at least a conceptual detail of the keyway.
Response to Adequacy Issue No. 13.
Wildcat is submitting a general description for the installation of the keyway and
liner. See Attachment 8.
Adequacy Issue No. 14.
Page 3, Construction. Item 5 states cut and fill slopes will not exceed 2:1. This is
apparently inconsistent with section A on Figure D -2. If the pond slopes are 2:1 as
stated on page 2 (Background), the cut slope above elevation 8760 as shown on Figure
D -2, is clearly steeper than 2 Furthermore, the second to last paragraph on page 8 of
Exhibit 6.5 discusses slopes not being steeper than 1:1 without DRMS approval, which
is not only incorrect, but inconsistent with Exhibit D, Attachment 6. DRMS will require
slope stability analyses addressing a) empty /dry conditions, b) full capacity conditions,
and c) rapid draw down conditions for any embankment design to impound water with
slopes greater than 3H:1 V.
DEN 97,591,786v1 9 -9 -11
GREENBERG TRAURIG, LLP • ATTORNEYS AT LAW • WWW.GTLAW.COM