1997-07-31_REVISION - M1981302

• Permit No: M1981302
• IBM Index Class Name: Revision
• Doc Date: 7/31/1997
• Doc Name: FLOODPLAIN ANALYSES DEEPE FARM PIT WESTERN MOBILE BOULDER TR TR-006 PN M-81-302
• From: DMG
• To: HART ENVIRONMENTAL
• Type & Sequence: TR6
• Media Type: D
• Archive: No

• III IIIIIIIIIIIII III E OF COLORADO
DIVISION Of MINERALS AND GEOLOGY
of
Department of Natural Resources
Sherman Roam 215
Denier,Colorado 80203
Phone:
e:I7031 866-6-3567
FAX:[phone]
DEPARTMENT OF
NATURAL
RESOURCES
Roy Romer
July 31, 1997 Governor
{a"sS Lcchhead
Mr . Michael J. Hart beculrve Director
Hart Environmental Michael B.Long
P .O. BOX 1303 Division D.,ector
Boulder, CO 80306
RE: Floodplain Analyses, Deepe Farm Pit, Western Mobile Boulder,
Technical Revision TR-006, Permit No. M-81-302
Dear Mr . Hart :
Reference is made to three memoranda from Allen Sorenson to Gregg Squire
and from Allen Sorenson to File No . M-81-302 dated May 25 and 26, 1997
and related to issues at the Deepe Farm Pit. The three memoranda are
titled Proposed Grading Plan, Guidelines for Floodplain Evaluation, and
General Notes on Deepe Farm Pit Floodplain Issues. These memoranda were
presented to Western Mobile Boulder to constitute the Division' s
adequacy review for the Deepe Farm Pit technical Revision TR-006 . These
memoranda required, in part, that Western Mobile "provide a floodplain
analysis that compares flood inundation that would occur if the
reclamation contours approved in 1989 were installed, to flood
inundation that would occur based on the reclaimed contours proposed in
technical revision TR-006 . " Since the time that the Division provided
the adequacy review for TR-006 to Western Mobile, the Division' s staff
has taken the opportunity to review numerous floodplain evaluations for
South Boulder Creek that are available. The floodplain studies that
have been reviewed by the Division include:
1 . 1973 R.W. Beck and Associates Major Drainage Planning
2 . 1986 Greenhorne & O'Mara, Inc . Flood Hazard Area Delineation
3 . 1996 Love and Associates, Inc . Floodplain Analysis
4 . 1996 Taggart Engineering, Inc . Floodplain Analysis-Phase I
5 . 1996 Taggart Engineering, Inc . Floodplain Analysis-Phase II
In addition to review of these floodplain studies, the Division has
consulted at length with the Floodplain Management Section of the
Colorado Water Conservation Board. Based upon this review of floodplain
information available for South Boulder Creek, the Division provided
testimony at a June 26, 1997 hearing before the Mined Land Reclamation
Board that it was the Division' s finding that the improvements to the
Deepe Farm Pit perimeter levee proposed in technical revision TR-006
will not result in damage to adjoining property during flooding, and
that the presence of an improved Deepe Farm Pit perimeter levee will