PERMFILE109999

• Permit No: M2000113
• IBM Index Class Name: Permit File
• Doc Date: 9/18/2001
• Doc Name: RESPONSE TO MEMO REGARDING FLOODPLAIN ISSUES DMG FN M-2000-113
• From: HIGH COUNTRY ENGINEERING INC
• To: DMG
• Media Type: D
• Archive: No

5EP-18-O1 TUE 03;46 PM
Memo
COUNTRY ENGINEERING
FAX NO, 97:94512555
To: Gregg Squire. Division of Minerals and Gefllogy
CC: Allen Sorenson, Division of Minerals and Geology
Steve Wujek, Knight Plannhig
Tim Thulsor>,13alcohn and Crcen
From: Leslie Flope, tilgh Country Ettgfneering, Illc.
Uatc: September 18, 2001
Re: Itcsponsc to Metno Regarding l~loodplain lssucs,l)MGFile No- M-2000-113
HCE Project No: 2011041.74 - Mamm Creek Gravel ktit
P, 01 /01
III IIIIIIIIIIIIIIII
sss
The purpGSe of this memorandum is to respond to the memorandum that Allen Sorenson,
DMG, sent to yott on September 17, 2001.
the proposed berms along rho norttl perimeter of l}tc gravel sites will be installed at tltc
beginning of the active mining in the pits. The inslellatiutt of the berms will progress when the
material for the berms is madu uvailnblc itt tl,e active mining pits. The application before you
propusvs lu keep the beans as a permanent wntcr control feature through the mining and
reclamaliun pltascs. Tlrorcforc, the bond amottnt should include the riprapping acrd berming of ~'
dtc bravcl pits at the beginning of the gravel mining.
The control sills will be planed at the doa~nstrcam end of each at:tive gravel pit at the
beginning of netive mining in each pit. This will pmvide the stormwater flows a conirGllcd
discharge paint. 'there will be four control sills, one at each downstream end of each pit. The
elevation difference between the cotttrol sills and the discharge points into the Colorado River
will be less than three feet. The U.S. Fish and Game has requested the crest clcvatiun for the
sills to be at normal hil;h water elevation, which is less than a tluee-foot drop, typically.
Additional channels should not be necessary to direct the 11ow towards the control sills since
the gravel mitilng will progress from upstream to downstream, in the direction of the control
sills. 'Thus, it would be appropriate for the Division to request bonding for four control sills
that will be required for the proposed pits.
Wa are coordinating the riprap design, bedding mau:ria] and riprap placement details with
Arlen Sorenson. Per Mr. SUIL'nSUlt~~ rcyucst, tltc riprap will be placed on the riverDide, crust
and pit sidu of Utc bean. 1'he riprap on tho pit side will end at the elovatiott of the riprap on the
riverside. All of tltcse flood cotttrol measures will be installed at the beginning of the gravel
utiuiug,
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