Grapevine Creek-CS 920810 Federal Emergency Management Agency
Washington, D.C. 20472
FILE corY
C~RT~FI~D M~L I~ REPLY R~F~R TO:
RETURN RECEIPT REQUESTED 102
The Honorable Mark Wolfe Case No.: 92-06-006P
Mayor~ City of Coppell Community: City of Coppell~ Texas
P.O. Box 478 Map Panel Number: 480170 0010 D
255 Parkway Boulevard Effective Date
Coppell, Texas 75019 of This Revision: A06 10 1992
Dear Mayor Wolfe:
This is in response to a letter dated October 18, 1991, from Mr~.M. Shohre
Daneshmand, P.E., Acting City Engineer, City of Coppell, regarding the
effective Flood Insurance Study (FIS) report and Flood Insurance Rate Map
(FIRM) for the City of Coppell, Texas, dated October 16, 1991. In his
letter, MrS. Daneshmand requested that we revise the effective FIRM to show
the effects of realignment of Grapevine Creek Channel, including the
construction of a grass-lined channel with a base width varying from 70 to
200 feet~ the construction of a concrete drop structure approximately
125 feet downstream of Interstate Highway 635, and the construction of a
bridge at Freeport Parkway along Grapevine Creek. Ail data required to
review this request were submitted by Ms. C. Jean Hansen, P.E., Albert H.
Halff Associates, Inc., with her letters dated October 7, 1991,
November 26, 1991, June 4, 1992, and July 7, 1992.
We have completed our review of the submitted data with the data~
regard
to
used to produce the effective FIRM, and have revised the FIRM to modify the
elevations, floodplain boundary delineations, floodway boundary delineations,
and zone designations of a flood having a 1-percent probability of being
equaled or exceeded in any given year (base flood) along Grapevine Creek from
Southwestern Boulevard to Interstate Highway 635 for a distance of
approximately 1.18 miles along the creek. The 100-year flood is contained in
the new channel in this reach. A public notice was issued in the City of
Coppell local newspaper, the Citizen's Advocate, on February 14, 1992, to
inform all adjacent property owners of the City's intent to modify the
100-year floodplain and the floodway.
The revised hydraulic analysis was provided in a report entitled "Request For
Final Letter of Map Revision on Grapevine Creek, Southwestern Boulevard to
IH 635 in the City of Coppell, Texas," prepared by Albert H. Halff
Associates, Inc., dated October 1991.
The modification is shown on the enclosed annotated copy of FIRM
Panel 0010 D, Profile Panel 06P, and the Floodway Data Table for Grapevine
Creek. This Letter of Map Revision (LOMR) hereby revises this panel of the
effective FIRM dated October 16, 1991.
The following table is a partial listing of former and modified base
(lO0-year) flood elevations (BFEs).
Existing BFE Modified BFE
Location *(feet) *(feet)
31,916 feet above the confluence with
Elm Fork of Trinity River and upstream
of Southwestern Boulevard *506 *506
35,306 feet above the confluence with
Elm Fork of Trinity River and 580
feet downstream of Freeport Parkway '514 '510
36,848 feet above the confluence with
Elm Fork of Trinity River and downstream
of drop structure '519 '513
36,931 feet above the confluence with Elm Fork of Trinity River and at the
City of Coppell city limits *522 *522
*National Geodetic Vertical Datum, rounded to the nearest whole foot.
Preliminary maps for the City of Coppell, Texas, were sent to your community
on December 18, 1991, and are due to be effective in December 1992. We will
incorporate the modifications described in this LOMR into the final maps
prior to final printing.
The floodway is provided to your community as a tool to regulate floodplain
development. Therefore, the floodway modifications described in this letter,
while acceptable to the Federal Emergency Management Agency (FEMA), must also
be acceptable to your community and adopted by appropriate community action,
as specified in Paragraph 60.3(d) of the National Flood Insurance Program
(NFIP) regulations.
We encourage you to disseminate the information reflected by this LOMR widely
throughout the community in order that interested persons such as property
owners, insurance agents, and mortgage lenders may benefit from this
information. We also encourage you to consider preparing an article for
publication in the community's local newspaper that would describe the
changes that have been made and the assistance the community should provide
in serving as a clearinghouse for these data and interpreting NFIP maps.
These modifications have been made pursuant to Section 206 of the Flood
Disaster Protection Act of 1973 (P.L. 93-234} and are in accordance with the
National Flood Insurance Act of 1968, as amended (Title XIII of the Housing
and Urban Development Act of 1968, P.L. 90-448), 42 U.S.C. 4001-4128, and 44
CFR, Part 65. Public notification of modifications to the BFEs along
Grapevine Creek will be given in the Citizen's Advocate on or about
August 21, 1992 and August 28, 1992. In addition, a Notice of Changes will
be published in the Federal Re~ister.
As required by the legislation, a community must adopt and enforce floodplain
management measures to ensure continued eligibility to participate in the
NFIP. Therefore, your community must enforce these regulations using~ at a
minimum, the BFEs, zone designations, and floodways in the Special Flood
Hazard Areas shown on the FIRM for your community~ including the previously
described modifications.
This response to your request is based on minimum floodplain management
criteria established under the NFIP. Your community is responsible for
approving all proposed floodplain developments, including this request, and
for ensuring that necessary permits required by Federal or State law have
been received. With knowledge of 'local conditions and in the interest of
safety, State and community officials may set higher standards for
construction, or may limit development in floodplain areas. If the State of
Texas or the City of Coppell have adopted more restrictive or comprehensive
floodplain management criteria, these criteria take precedence over the
minimum NFIP requirements.
The basis of this LOMR is a channel-modification project. NFIP regulations,
as cited in Section 60.3(b)(7), require that communities assure that the
flood-carrying capacity within the altered or relocated portion of any
watercourse is maintained. This provision is incorporated into your
community's existing floodplain management regulations. Consequently, the
ultimate responsibility for maintenance of the channel modification rests
with your community.
The community number and suffix code listed above will be used for all flood
insurance policies and renewals issued for your community on and after the
effective date listed above.
The modifications described herein are effective as of the date of this
letter. However, within 90 days of the second publication in the Citizen's
Advocate, your community may request that we reconsider this determination.
Any request for reconsideration must be based on scientific or technical
data. Ail interested parties are hereby notified that, until the 90-day
period elapses, the determination may be modified.
Please note that FEMA is currently developing detailed application and
certification forms for use in requesting revisions or amendments to ~NFIP
maps. Forms will be available this summer and will be used for requests
received by FEMA on or after October 1, 1992. These forms will highlight
technical considerations in a fashion that facilitates an efficient review;
therefore, use of these forms prior to October 1 is strongly recommended.
Application forms should be available after July 1 for Letter of Map
Amendment and LOMR Based on Fill requests, and after September 1 for the more
common types of revision requests.
If you have any questions regarding the modifications described herein,
please call the Chief, Natural Hazards Branch, FEMA, in Denton, Texas, at
(817) 898-5107, or Mr. Alan Johnson of my staff in Washington, D.C., at
(202) 646-3403.
Sincerely,,
\'£,,~' ~ ' .
William R. Locke
Chief, Risk Studies Division
Federal Insurance Administration
Enclosures
cc: W/Mr~.M.. Shohre Daneshmand, P.E. City of Coppe~l
Ms. C. Jean Hansen, P.E.
Albert H. Halff Associates, Inc.
FLE'VATION ~FEET NGVD)
~ ......... ~ ........................ -~...~h '~ ....... :~ ....... t .... ~om'~v~.~-7.~-. - -~-~
U:... : : · i. ':'': :' : .... -''-!':.':~_'' :-\::'::i'-'2='---~=--'-:--'----2=-':--:::-:..2;==:.-' :
~.-~.'--'7-i"-'~ .... X ..... :'-.. :--?-:-il ..... :::.:---*.¥i'i_~-=- \-_:~..-:~_i---.=.---~=:-,-~'..¥~=-::-::i¢-~=::~=
~ ~ :_ ......... -.----- -_:_ .:_ _- ~ :: ..-: : , ~:_..~ .._~:-~.::
:~ ' . _. !:-===============================
..... ~l ..... [': l:*'r~:-:=':iY'-':"':"2~-=-==":" '
~. : ...... ~ .. . ~ ~'.,-:::?,::::'....::-~- . :.:.:..- :
~ - · _t''~-''1. ........... ~ -.-:-i . .
~ ~- ....... , - :- . -f--[-f .........................
~. ~ . · ~. - ,, x. , . ! '~' ' '~ ' ~'''~ ..... I .... ~ ......
~ ,~---'--'-' .... --: ....... ~-: ..... -.-----:~------X----- '!" ', '\~. "\"," ~'~'t-~^¥ i~0e£t'v~:i : --:
~ ~ ........ '\ ' 'X ~ I'-~-~- · -:- --
~ ': . :* · .: , .i~ 3; ....~ .'...' .
~ ................ : ...... : ~ ...... , .......... ~,.\-~ ....-.. :.: ..... ;:--.:~._-
~ ' ' ': ': :'.. . ': . : I:" ,~ ' '~ !X' ~,'' I ....... ~ .......
~..~.- ~' ........ :. . . .: i ..:, ' ' ','~ ...... \ ~ '-'~ ...........
....~ ..... . ...., ......~ .....
=~§~ ....... ..... : .................................. ~ . ._'.__ ........... ~- i ." ,~i ~iFa~.~::,u,?' .. . _ _--_.~_~:-_~^~:,.,.^:..' .___._..,
_~ ,,.--.. .- X,, i .N~: '':.:
~ !.: '!':.' ' i ' ' \,' '~ .... X'-'.~,~- ....... :-:':r ....
~ .... :>RO:~ .qFR 'C.I"'R~'· ! ~.~ ~. I i '
~ i .'. :_''2 ' i -~ : .i
~:1 . .. -
= F~.. . '' '1
-. : ..... ' i ...... i ......
i '' ' '' ; '' '- '-- - i .......................................... ; ....
· -2 -~---: ................................................. ~._~_ ........
- . ...... . .... : ............... !.~ ......
i .: _ ....
~-° ~ - ~.:'.'.:'.:'.CI~. : .................................... +-; ........
-~ ~ ~ .... ..,,q.-~., ............................ -...;..= .... .',_..:_.
~ i ~ "~· '~' ~ ........ =:::":-=:-*-~-=-"=7:..:.--.:-::':[-r=-;-:-:'-:' -
§ ::-.: i:: :.i::'JS '::: :: =:!: ::'::"::' ==:':::--:-:::-:===:-::-'-:: :--::
....................... :. --,: ....... :._-- L=: - · -::: i"-:';-:-: :=~-:: :_:-_'_L: :_. :£_: ~..:.. ' .:
FED~ [M[RG~NCY MANAG[MEIfl' AGENCY
,-, FLOOD PROFILES
o-,..~ CITY OF COPPELL, TX
[DALLAS AND DENTON COS.) GRAPEVINE CREEK
._ .. ~ ~. ~ ~.. ~.~ ~
~ :'. ~ ~ .~-~~:__..-~:-~
. ~
~" O ,~ ~ ~
. ~OP~EbK ......... ROAD ~ ~
~ ..................... ~ . ..... '-- ~ X
- ~ Z
~ ~ i N
,
.
...:'~
TABLE 2