Grapevine Creek-CS 920828 £
CHANGES .AJ~E MADE IN DETERMINATIONS OF BASE FLOOD
ELEVATIONS FOR THE CITY OF COPPELL, DALLAS COUNTY,
TEXAS, UNDER THE NATIONAL FLOOD INSURANCE PROGRAM
On October 16, 1991, thc Federal Emergency Management Agency (FEMA)
identified Special Flood Hazard Areas (SFHAs) in the City of Coppell, Dallas County,
Texas, through i~suance of a Flood Insurance Rate Map (FIRM).
The Administrator, Federal lasurancc Administration (FIA), has determined that
modification of the clcvatious of the flood having a 1 -percent chance of occurrence in
any given year Coasc flood) for certain locations in thc City of Coppell is appropriate.
The modified base (100-yea0 flood elevations (BFEs) revise the FEMA FIRM for thc
community.
Thc changes are being 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 thc Housing and Urban Development
Act of 1968, P.L. 90-448), 42 U.S.C. 4001-4128, and 44 CFR Part 65.
A hydraulic analysis was performed to incorporate thc realignment of Grapevine
Creek Channel, including thc construction of a grass-lined channel with a base width
varying from 70 to 200 feet, the construction of a concrete drop structure approxi-
matcly 125 feet downstream of Interstate Highway 635, and thc construction of a
bridge at Freeport Parkway, and has resulted in a revised delineation of thc regulatory
floodway a reduction in SFHA, and lower BFEs from upstream of Southwestern
Boulevard to Interstate Highway 635. Thc aforementioned channclized portion of
Grapevine Crcck contains the 10-, 50-, 100-, and 500-year floods. The table below
indicates thc modified BFE~ for several locations along thc affected length of
Grapevine Creek.
Existing BFE Modified BFE
Location *(Feet) * (Feet)
Approximately 31,916 feet above confluence
with Elm Fork of Trinity River and upstream
of Southwestern Boulevard *506 *506
Approximately 35,306 feet above confluence
with Elm Fork of Trinity River and 580 feet
downstream of Freeport Parkway *514 *510
Approximately 36,848 feet above confluence
with Elm Fork of Trinity River and downstream
of drop structure '519 '513
Approximately 36,931 feet above confluence
with Elm Fork of Trinity River and at City
of Coppell limits *522 *522
· National Geodetic Vertical Datum, rounded to nearest wholc foot
Under thc above-mentioned Acts of 1968 and 1973, the Administrator, FIA, must
develop criteria for floodplain management. For the community to participate in thc
National Flood Insurance Program (NFIP), the community must use the modified
BFEs to administer the floodplain management measures of the NFIP. These modified
BFEs will also be used to calculate the appropriate flood insurance premium rates for
new buildings and their contents and for the second layer of insurance on existing
buildings and contents.
Upon the second publication of notice of these changes in this newspaper, any
person has 90 days in which he or she can request, through thc Chief Executive Officer
of the community, that thc Administrator, FIA, reconsider thc determination. Any
request for reconsideration must be based on knowledge of changed conditions or new
scientific or technical data. All interested parties are on notice that until thc 90-day
period elapses, the Administrator's determination t9 modify the BFEs may itself be
changed.
Any person having knowledge or wishing to comment on these changes should
immediately notify:
The Honorable Mark Woffc
Mayor, City of Coppell
255 Parkway Boulevard
P. O. Box 478
Coppell, Texas 75019
2t,8-28
Citizens' Advocate August 28, 1992