Alexander Ct-CS070821
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<brad .pickering@kimley-horn.com>
<kgriffin@ci.coppell.tx.us>
<mboyd@ndmce.com>, <ojohnson@ndmce.com>
8/21/20076:12 PM
Grapevine Creek/Alexander Court Ultimate Study Review
20070821.pdf
Ken,
Attached is the review letter for the Grapevine Creek/Alexander Court
Ultimate Study, dated August 2007, prepared by Nathan D. Maier
Consulting Engineers, Inc. You will receive a hardcopy of the review
letter by mail.
If you have any questions, please do not hesitate to contact me.
Thanks,
Brad Pickering, EIT (TX), CFM
Kimley-Horn and Associates, Inc.
12700 Park Central Drive, Suite 1800
Dallas, Texas 75251
p: (972) 776-1781
f: (972) 239-3820
e: brad.pickering@kimley-horn.com
<mailto: brad .pickering@kimley-horn.com>
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Kimley.Horn
and Associates, Inc.
August 21, 2007
Mr. Kenneth M. Griffin, P.E.
Director of EngineeringlPublic Works
255 Parkway Boulevard
Coppell, TX 75019
RE: Ultimate Condition Study Review
Grapevine Creek/Alexander Court
KHA No.: 063124008
Dear Mr. Griffm:
Kimley-Horn and Associates, Inc. (KHA) has performed the ftrst review of the
Grapevine Creek illtimate Conditions Study for Alexander Court, dated August
2007, prepared by Nathan D. Maier Consulting Engineers, Inc. (NDMCE).
KHA reviewed the document for adherence to currently published City of
Coppell drainage design guidelines. KHA recommends that NDMCE address the
following items:
1. The flow change locations used in the ultimate conditions study are
inconsistent with the flow change locations in the City-Wide Storm Water
Management Study for the City of Coppel!, dated January 1991, prepared
by Albert H. HaltI Associates, Inc. Revise the flow change locations to
be consistent with the Halff study or explain the discrepancy.
2. The known starting water surface elevation used for the ultimate
condition proftle is inconsistent with the City-Wide Storm Water
Management Study for the City ofCappell. Revise the starting water
surface elevation to be consistent with the Halff study or explain the
discrepancy.
3. The mapped top width at cross section 27540 does not reflect the HEC-
RAS model output. Revise the floodplain delineation at this cross
section to be consistent with the HEC-RAS model.
4. Revise the Floodplain Work Map to show the entire studied reach, the
extent of the model cross sections, and the cross section labels.
5. The Floodplain Work Map or report should include a water surface
elevation table showing the ultimate condition water surface elevation
for each lot to be used to set the minimum ftnished floor elevation.
.
TEL 972 no 1300
FAX 972 239 3820
.
Slite 1800
12700 Park Central Drive
Dallas, Texas
75251
~=~
Kimley-Horn
and Associates, Inc.
Mr. Kenneth M. Griffm, P.E.
August 21, 2007
Page 2 of2
Please note that the ultimate condition floodplain delineation encroaches heavily
on several of the proposed lots. Should any grading be proposed within the
ultimate condition floodplain boundary, a proposed condition floodplain study
will need to be submitted to the City for review.
If you have any questions regarding the comments included in this letter, please
feel free to contact us at 972.770.1300.
Sincerely,
KIMLEY.HORN AND ASSOCIATES, INC.
~-,..~
Steven D. Galloway, P.E., CFM
~_~.CFM
Cc: Michael Boyd, P.E.; Nathan D. Maier Consulting Engineers, Inc.
G:\HYDRO\PROJECTS\63124008\Alexander Court\20070821.doc