Westhaven-CS120803 HALFF
August 3, 2012
AVO 28875
Mr. Kenneth M. Griffin,P.E.
Director of Engineering and Public Works
City of Coppell
PO Box 9478
Coppell,Texas 75019
RE: Review of Floodplain Study Submittal by Kimley-Horn and Associates, Inc.-
Conditional Letter of Map Revision (CLOMR) for Westhaven Residential
Development—Denton Creek
Dear Mr. Griffin:
We have completed the technical review of the Conditional Letter of Map Revision (CLOMR)for
Westhaven Residential Development— Denton Creek prepared by Kimley-Horn and Associates, Inc.
As of result of this review, we believe that the stream hydraulics and floodplain mapping on
Denton Creek for the Westhaven Residential Development along Denton Creek generally
conforms to City of Coppell floodplain ordinance,regulations and policies.
The following comments are a result of this review:
1. The proposed project seems to have no significant impact on water surface elevations
on Denton Creek.
2. The proposed project seems to have no significant impact on velocities on Denton
Creek.
3. Valley storage loss on Denton Creek due to the project does not exceed the
maximum allowable of 15%. Valley storage reductions for the standard project flood
event was not determined since the proposed project modifications have no
significant impact on the standard project flood backwater elevation from the Elm
Fork of the Trinity River.
Based on this information,Halff Associates recommends approval.
This review was performed for the benefit of the City of Coppell. This is not a detailed
engineering review of any construction plans, and Halff Associates, Inc. assumes no liability
for the planning, design,or construction of the project.
HALFF ASSOCIATES,INC.
1201 NORTH BOWSER ROAD TEL (214)346-6200 WWW.HALFF.COM
RICHARDSON,TX 75081-2275 FAX(214)739-0095
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Mr.Kenneth M.Griffin,P.E.
City of Coppell
H ALF F
August
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Do not hesitate to call me 214 at 346-6245 if you have further questions concerning this
review. Please include the reference"AVO 28875" on all correspondence.
Sincerely,
HALFF ASSOCIATES,INC.
1 44.14A_ &4,64%,
Russell P. Erskine,P.E., CFM
Project Manager
C: Kyle A. Dickey,P.E.
Kimley-Horn and Associates,Inc.
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