Townhouses-AG001212 CITY COUNCIL MEETING: December 12 2000 ITEM
ITEM CAPTION:
Consider approval of a variance to Floodplain Management Ordinance No. 94-639 Article 4, Section C,
paragraph 3 which requires offsetting valley storage for development within the floodplain for the development of
Townhouses of Coppell, 48 acre site south of Sandy Lake Road and east of MacArthur Blvd.: and the City's
existing 0.5 million gallon ground storage tank site on Sandy ]~ake Road.
APPROVED
SUBMITTED ~ CITY COUNCIL
Kenneth M Gri/~, PE
TITLE:~ Dxrector of Enmneenng/IMbttc Works DATE
STAFF COMMENTS:
See attached memo.
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BUDGET AMT. $ AMT. EST. $ +k-BID $ _\-.
FINANCIAL COMMENTS: . ~~.~~\
DIP.. INITIALS: ~ FIN. REVIEW: ~] ~ CITY MANAGER.. RE .
Agenda Request Form - Revised 5/00 Document Name:. #eng5
MEMORANDUM
FROM THE
DEPARTMENT OF ENGINEERING
To: Mayor and City. Council Members
From: Kenneth M. Griffin, P.E., Dir. of Engineering/Public Works Vy
Date: December 12, 2000
RE: Consider approval of a variance to Floodplain Management Ordinance No. 94-639
Article 4, Section C, paragraph 3 which requires offsetting valley storage for
development within the floodplain for the development of Townhouses of Coppell, 48
acre site south of Sandy Lake Road and east of MacArthur Blvd., and the City's
existing 0.5 million gallon ground storage tank site on Sandy Lake Road.
Whv a variance request? Because new floodplain maps to be adopted in 2001 will remove the
properties in question from the floodplain and eliminate the need for valley storage. Now', for the rest of
the sto~':
For some time now, the Engineering Department has been discussing floodplain issues w,ith potential
developers of the proposed Towxuhouses of Coppell and the 48-acre triangular tract of land immediately
east of the Townhouses of Coppell. Both properties lie generally near the southeast comer of MacArthur
and Sandy Lake (see exhibit). Our official Floodplain Map dated April 15, 1994 shows portions of both
properties within a 100-year floodplain, i.e. a Floodplain Management Area. For development within a
Floodplain Management Pa'e~ a Floodplain Development Permit is required per Article 4, Section C of
the Floodplain Management Ordinance. The definition of a Floodplain Management Area is "The
combination of all floodplain and regulatory floodways within the jurisdiction of the Cio', including
floodplain land that is not identified on Floodplain Hazard Boundats.' Maps or Flood Insurance Rate
Maps." Because portions of these properties are currently within a Floodplain Management Area, we
have had numerous meetings conceming how' to satisfy paragraph 3 of Section C. Paragraph 3 basically
states that when you develop within a floodplain and are removing valley storage from the floodplain you
need to compensate for a portion of that loss.
During discussions with the developers, I informed them that I was interested in acquiring additional land
for a future pump station and ground storage tank generally to be located at our existing site. It was then
mutually agreed that the relocation of our site away from Sandy Lake could be a benefit. For the City it
would allow' us to relocate off of a main entry into the City and get us closer to a 24" water line in
MacArthur Blvd. and for the developer of the 48 acres it would remove the obstruction of a pump station
and ground storage tank from the main entry., point to their development. Because of the potential for a
land swap with the owner of the 48-acre tract of land, we also need to be included in this variance request.
T~pically, I would not entertain any variances to the Floodplain Management Ordinance that resulted in
development that did not meet the strict intent of the ordinance. However, in this particular case there is a
"CITY OF COPPELL ENGINEERING - EXCELLENCE BY DESIGN"
proposed revision to the floodplain maps that will remove the properties in question from the floodplain.
Once those properties are removed from the floodplain they no longer fall under the requirements of the
Floodplain Management Ordinance. Therefore, there would be no valley storage requirement because
there would technically be no reclamation required from the floodplain.
The new updated maps should become effective in mid-2001. The proposed revised maps were originally
provided to the City in October 1999. One aspect of a revision to a floodplain map is a ninety-day appeal
period. Notices were placed in the local paper on January 28, 2000 and February,' 4, 2000 concerning the
revisions to the floodplain map. During the 90-day appeal period, there were three appeals filed with the
Federal Emergency Management Agency (FEMA). One appeal was from the US .Arm)' Corps of
Engineers, which provided additional information on an Upper Trinity River Study. A second appeal was
from Nathan Maler Engineering, Inc. concerning the impact of the revised floodplain maps on the
property owned by his client, Terry.' Holmes, on the north side of Sandy Lake at Denton Creek. The third
appeal was from the City of Carrollton.
On September 7, 2000, FEMA issued a letter stating that the appeals for our community had been
resolved. That letter started a thirty-day comment period after which FEMA would address any
comments and then resume the timeline for implementing the revised map. The last step for FEMA in
implementing the revised floodplain map is the issuance of a Letter of Final Determination. The Letter of
Final Determination begins a six-month compliance period and establishes an effective date for the new
floodplain map. During the six-month compliance period, we will be revising our floodplain ordinance to
adopt the new floodplain map. In recent conversations v,4th FEMA, it is my understanding that the Letter
of Final Determination could be issued at any time.
I go into great detail concerning the status of our floodplain maps in relationship to this request for a
variance to show that if the developer of the Towv. houses of Coppell, the 48 acre tract of land and the City
were required to build extensive valley storage to offset reclamation from the floodplain, as defined on the
1994 map, that requirement would go away once the new maps are adopted. As is often said, timing is
everything. If there had been no appeals to the proposed map the new map would currently be in place
and there would be no requirement for valley storage or a variance request. Also, if no property were
currently proposing development, there would be no need for a variance request.
I am trying to apply a degree of common sense to this complicated issue. The new' maps will be adopted
sometime in the year 2001 showing that the properties in question will not be within a designated
Floodplain Management Area. Therefore, I am recommending that the City grant a variance to Article 4,
Section C, paragraph 3 of the Floodplain Management Ordinance No. 94-639 to eliminate the need for
offsetting valley storage for the development of the Tovmhouses of Coppell. the 48 acre tract of land east
of the Townhouses of Coppell and the City's 2.5 acre tract of land that currently houses our 0.5 million
gallon ground storage tank.
The offsetting valley storage is a local amendment to the minimum National Floodplain requirements. So
while a variance might be granted to the requirement for valley storage all other aspects of the Floodplain
Ordinance still must be adhered to by the Townhouses of Coppell while the new maps are being adopted
to insure compliance with federal regulations.
Staff will be available to answer any questions at the Council meeting.
"CITY OF COPPELL ENGINEERING - EXCELLENCE BY DESIGN"
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Storage
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AN ORDINANCE OF THE CITY OF COPPELL
ORDINANCE NO. ¢'-/d. q
jan ORDINjaNCE OF THE CITY OF COPPELL, TEXAS, AMENDING THE CODE
OF ORDINANCES OF THE CITY OF COPPELL, TEXAS, BY AMENDING ARTICLE 16-
4, FLOODPLAIN MANAGEMENT ORDINANCE; PROVIDING FOR COMPREHENSIVE
MANAGEMENT OF FLOODPLAINS IN THE CITY OF COPPELL; PROVIDING A
TITLE; SHOWING STATUTORY AUTHORITY; LISTING FINDINGS OF FACT;
STATING PURPOSES AND METHODS; DEFINING SCOPE OF AUTHORITY;
OUTLINING THE ORGjaNIZATION OF THIS ORDINANCE; PROVIDING
DEFINITIONS OF TERMS; DEFINING LANDS TO WHICH THE ORDINANCE
APPLIES; IDENWIFYING AREAS AND METHODS OF DETERMhNING SPECIAL
FLOOD HAZARDS; ESTABLISHING A PENALTY OF FINE NOT TO EXCEED FIVE
HIo."NDRED DOLLARS ($500.00) FOR NONCOMPLIANCE; DEFINING PREVAILING
RESTRICTIONS; MAKING INTERPRETATION PROVISIONS; PROVIDING WARNINGS
AND DISCLAIMERS OF LIABILITY; ESTABLISHING ADMINISTRATIVE ,SAND
VARIjaNCE PROCEDURES, INCLUDING PERMITS; DESIGNATION OF CITY
ENGINEER AS .&DMINISTRATOR; DEFINING DIoWIES AND RESPONSIBILITIES OF
THE ADMINISTRATOR; MAKING GENERAL AN'D SPECIFIC DESIGN AND
. PERFORMANCE PROVISIONS FOR METHODS OF REDUCING LOSSES; PROVIDING
· FOR THE REPEAL OF ORDINANCE 87-390 AND ALL ORDINjaNCES IN CONFLICT;
PROVIDING A SEVERABILITY CLAUSE; PROVIDING A SAVINGS CLAUSE; AND
PRO'~qDING AN EFFECTIVE DATE.
BE IT ORDAINED BY THE CITY COUNCIL OF THE CITY OF COPPELL, TEXAS:
SECTION 1. That the Coppell City Code be, and the same is hereby, amended by
amending Article 16-4 to read as follows:
'ARTICLE 164 FLOODPLAIN MANAGEMENT ORDINANCE
ARTICLE 1
Adoption and Title, Statutory Authority, Findings of Fact, Purposes and Methods,
Scope of Authority, and Organization.
SECTION A. Adoption and Title
This Ordinance is hereby adopted and shall be known as the "Floodplain Management
Ordinance" of the City of Coppell.
AGG0~228
"Encroachment".
"F/ood£/a/n management" The operation of an overall program of corrective and
preventive measures for reducing flood damage including, but not limited to,
emergency preparedness plans, flood control works and floodplain management
regulations.
floodways within the jurisdiction of the City, including floodplain land that is not
identified on Flood Hazard Boundary Maps or Flood Insurance Rate Maps.
"F/oodp/a/n managenu~ mgu/at/o~" The zoning ordinances, subdivision regulations,
building codes, health regulations, special purpose ordinances (such as this floodplain
ordinance), and other applications of police power. The term describes such City,
County, State, or Federal regulations, or any combination thereof, which provide
standards for the purpose of flood damage prevention and reduction.
"Flood protection system" Those physical structural works for which funds have been
authorized, appropriated, and expended and which have been constructed specifically
to modify flooding in order to reduce the extent of the area within the City subject
to a "special flood hazard" and the extent of the depths of associated flooding. Such
a system typically includes channel improvements, reservoirs, levees or other
specialized flood modifying works constructed in conformance with sound engineering
standards.
"F/oodproo. fing" Any combination of structural and non-structural additions, changes,
or adjustments to structures which reduce or eliminate flood damage to real estate
or improved real property, water and sanitary facilities, structures and their contents.
"F/ood-m/med eros/on" The collapse or subsidence of land along the riverine flow line,
or banks, the shore of a lake or other body of water as a result of undermining
caused by waves or currents of water exceeding normal and anticipated levels or
suddenly caused by an unusually high water level in a riverine or lacustrine
environment accompanied by a severe storm, or by an unanticipated force of nature,
such as a flash flood or an abnormal surge of water from some similarly unusual or
unforeseeable event which results in flooding.
"F/ood-re/ated eros/on area manage" The operation of an overall program of
~.. ;
· . ;-. corrective and preventive measures for reducing flood-related erosion damage,
~ including but not limited to preparedness plans, flood-related erosion
emergency
control works, and floodplain management regulations.
"F/ood~vay" See "Regulatory floodway.'
assume the cost of any modifications noted by FEMA, as a result
their technical reviews, to be required for proper completion.
c Require the developer to submit an as-built )orr of
floodplain development conditions as soon as g the
qoodplain is completed. Encourage the expeditious of the as-
bu.', conditions in order to obtain the final le~ of map revision
from he FEIMA.
12. Make submittals tc CEMA in compliance with provisions of this ordinance
and the provisions ot 44 CFR.
13. Maintain and hold open t,, publ all records including maps,
elevation certificates and floodproofing, permits issued
variances, appeals, and so or, quired by or generally pertaining to the
provisions of this ordinane.
14. Review, approve or aeny all apg development permits required
by adoption of t~'., ordinance.
15. Make int~ pretations as needed to detern,~e exact location of the
bound~ ~es of floodplain management areas or hazard areas.
16. l~'otify the affected communities and the Texas :al Resource
Conservation Commission prior to any alteration or of a
watercourse, and submit evidence of such notification to Federal
Emergency Management Agency.
17. Obtain and reasonably utilize base flood elevation data and floodway
available from a Federal, State, or other source, when those data have not
been provided as outlined in Article 3, Section B, in order to administer the
provisions of Article 5.
SECTION C. Floodplain Development Permit
A Floodplain Development Permit shall be required for all new construction,
development, and encroachment, including the placement of manufactured homes,
within the floodplain management areas of the City. Application for a Floodplain
Development Permit shall be presented to the Floodplain Administrator on City
permit forms or facsimiles thereof, which include drawings (to scale) and technical
information sufficient to fully support the compliance of the proposed development
with the provisions of this ordinance. These data shall include, but are not necessarily
limited to, information which demonstrates the effects of such developments on the
floodplain, including impacts on the floodplains, floodways, flood elevations, and
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velocities within the channel of the 2-year and 100-year mean recurrence interval
floods and in the discharges of the effective FIS upstream of, downstream of, and
along or through the proposed development, and further, the person making
application shall:
~~/Y~ow the lowest floor elevated to a minimum of two (2) feet above the me
base t~oddL~-'~tion or to one (1) foot above the design by,~ n~tl ~levation,
whichever is higher. Lq IBt.'~'"',~ nf as~su~ptt[, the energy gradient
3. Demonstrate, with technical data, the impacts on the design base flood
storage capacity of the floodplain for all developments which include fill
within the floodplain. Generally, the following requirements shall be met:
a. For drainage areas of 0 to 11210 square miles the valley storage
reduction shall not exceed 15% for the 100-year flood and 20% for the
standard project flood;
b. For drainage areas in excess of 100 square miles the valley storage
reduction shall not exceed 0% for the 100-year flood and 5%, for the
standard project flood.
4.Demonstrate with technical data that the flood carrying capacity within the
altered or relocated portion of any watercourse is maintained.
5. Demonstrate with technical data that at any point within the
cumulative effect of the proposed development when combined wi~ other
existing and approved proposed development:
Will not increase the water surface elevations design base flood
urbanized watershed);
b. W: increase the effective base flood (existing condition
wat~ by m, one foot;
c. Will not increase flood water surface elevations of the FIS
regulatory floo ct at the time of application for a floodplain
developm,
d. Ot meets the provisions .cie 5 of this ordinance.
6. technical data for the Floodplain rator's review and
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