Alexander Ct-CS070530
Page 1 of 1
Ken Griffin - Fwd: Grapevine Creek/Alexander Court LOMR Review
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From:
To:
Date:
Subject:
CC:
Attachments:
Ken Griffin
mboyd@ndmce.com
5/30/2007 12:55 PM
Fwd: Grapevine Creek! Alexander Court LOMR Review
brad. pickering@kimley-horn.com
20070523.pdf
Mike
The review letter from Kimley-Hom for the Alexander flood study is attached.
Please make necessary changes. It probably would be quicker to work directly with K-H.
Ken Griffin, P. E.
Director of Engineering/Public Works
972-304-3686
kg-Ii ffi1}@ci.cQlli2t;ll.tX.JIS
>>> <brad.pickering@kimley-hom.com> 5/23/20075:01 PM >>>
Ken:
As discussed this afternoon with Nadia Dahab, attached are KHA's comments for the Grapevine Creek LOMR
application for Alexander Court, dated April 26, 2007, prepared by Nathan D. Maier Consulting Engineers, Inc. If
you have any questions regarding the attached comments, please do not hesitate to give us a call.
Thank you,
Brad W. Pickering, EIT (IN), CFM
Kimley-Horn and Associates, Inc.
12700 Park Central Drive, Suite 1800
Dallas, TX 75251
p: (972) 776-1781
f: (972) 239-3820
e: brad.pickering@kimley-horn.com
file://C:\Documents and Settings\rbrother\Local Settings\Temp\XPgrpwise\465D7427City _'" 1/8/2008
i (1/8/2008) Ken Griffin - Grapevine Creek/Alexander Court LOMRReview
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From:
To:
CC:
Date:
Subject:
Attachments:
<brad .pickering@kimley-horn.com>
<kgriffin@ci.coppell.tx.us>
<Steve.Galloway@kimley-horn.com>, <Ebenezer.chiluka@kimley-horn.com>, <n...
5/23/2007 5:06 PM
Grapevine Creek/Alexander Court LOMR Review
20070523.pdf
Ken:
As discussed this afternoon with Nadia Dahab, attached are KHA's
comments for the Grapevine Creek LOMR application for Alexander Court,
dated April 26, 2007, prepared by Nathan D. Maier Consulting Engineers,
Inc. If you have any questions regarding the attached comments, please
do not hesitate to give us a call.
Thank you,
Brad W. Pickering, EIT (IN), CFM
Kimley-Horn and Associates, Inc.
12700 Park Central Drive, Suite 1800
Dallas, TX 75251
p: (972) 776-1781
f: (972) 239-3820
e: brad.pickering@kimley-horn.com
~=r~
Kimley-Horn
and Associates, Inc.
May 23, 2007
Mr. Kenneth M. Griffin, P.R.
Director of Engineering/Public Works
255 Parkway Boulevard
Coppell, TX 75019
RE: Letter of Map Revision (LOMR) Review
Grapevine Creek/Alexander Court
KHA No.: 063124008
Dear Mr. Griffin:
Kimley-Horn and Associates, Inc. (KHA) has performed the first review of the
Grapevine Creek LOMR application for Alexander Court, dated April 26, 2007,
prepared by Nathan D. Maier Consulting Engineers, Inc. (NDMCE).
KHA reviewed the document for adherence to currently published City of
Coppell and Federal Emergency Management Agency (FEMA) drainage design
guidelines. KHA recommends that NDMCE address the following items:
1. The MT -2 Form 2, page 1 of 2, states that the upstream tie-in of the
study is at cross section 27620. Cross section 27900 has been added to
the revised existing conditions model and is not included in the effective
model. Revise the forms to reflect an effective tie-in upstream of the
model modifications.
2. Revise the Floodplain Work Map to include the benchmarks and vertical
datum used for the on-ground survey.
3. The water surface elevations table in the report text is not consistent with
the modeling output for the effective floodway HEC-RAS model.
Revise the report to be consistent with the modeling output.
4. Revise the Location Map to reflect the boundaries of the LOMR
submittal.
5. Cross section 22600, the location of the downstream effective tie-in, is
not shown on the Floodplain Work Map. Revise the workmap to show
this cross section.
.
TEL 972 770 1300
FAX 972 239 3820
.
Suite 1800
12700 Park Central Drive
Dallas, Texas
7525t
~=~
Kimley-Horn
and Associates, Inc.
Mr. Kenneth M. Griffin
May 23, 2007
Page 2of2
6. The sum of reach lengths for the HEC-RAS revised condition model
does not match the sum of the reach lengths in the FEMA effective
model. Revise the reach lengths in the revised condition model or
explain this discrepancy.
7. The report text states that Manning's 'n' values were taken from the
effective model, but they vary from the effective model at multiple
locations. Revise the model to be consistent with the effective modeling
or justify the proposed Manning's 'n' values.
8. Property owner notification is required by NFIP regulations 65.7(b)(1)
due to the floodway revision. The notices must include the extent of
revision, the changes to the floodway, and contact information for any
interested parties.
9. Revise the legend on the Floodplain Work Map to reflect revised existing
conditions and not proposed conditions.
10. Future development adjacent to the subject reach shall respect both the
100-year fully developed and FEMA effective floodplain boundaries.
Please note that any future development adjacent to the subject reach will need to
comply with all of the provisions set forth in the ordinances of the City of
Coppell including, but not limited to, the Subdivision Ordinance, Zoning
Ordinance, and Floodplain Management Ordinance.
If you have any questions regarding the comments included in this letter, please
feel free to contact us at 972.770.1300.
Sincerely,
KTMI"EY-HORN AND ASSOCIATES, INC.
~~96~
Steven D. Galloway, P.E., CFM
~(k:~rr'CFM
G:\HYDRO\PROJECTS\63 I 24008\Alexander Court\20070523.doc