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TO: Alan Ratliff, City Manager
FROM: Russell R. Doyl~~., City Engineer
RE: Funding for Two (2) Preliminary Phase Engineering Studies with
Reports for Pelican and Bethel School Road Sites
During and after the July 12, 1988, storm that caused the Town Center power
service to fail, and interrupted the City Council meeting; there were a
number of reported flooding areas. This storm was purported to be greater
than the one hundred (100) year frequency.
Of all the reports on flooding, only the two (2) sites involved structural
or residential flooding. These were in and around Site (1) 763,767 and 771
Pelican, and Site (2) 721, 725 and 726 E. Bethel School Road. These two (2)
areas are out of separate subdrainage systems that collect stormwater and
carry it to Grapevine Creek. It appears in both cases, that the existing
drainage system is not of ample size to handle these more severe storm
events.
Therefore, we request approval for non-budgeted funds not to exceed $3,500
to retain Ginn, Inc. and conduct these two (2) Preliminary Phase Studies
with reports. This funding includes an estimated fifty-six (56) man hours,
and the preliminary phase study worked into other workloads will take an
estimated three to four (3-4) weeks.
Per the work order submitted by Ginn, Inc., this Preliminary Phase
Engineering Study will collect data, from the construction drawings and
files, conduct an engineering analysis and preliminary design developingone
to three (1-3) alternatives to provide relief (or improved drainage) to each
of these two (2) areas. The report will include, but not be limited to, an
estimated construction and final engineering design cost for each of the one
to three alternatives proposed by the consultant engineers.
We will then return with each recommended alternative to get approval of
funding and solicit final design engineering services for each selected
alternative. If approved and funded, then we will cause the final design to
take place, advertise for bids, award and supervise the construction.
Please note that the traditionally prioritized list for fixing drainage
problems is as follows:
1) Loss of life.
2) Structural (or residential) flooding.
3) Public street flooding, obstructing.
emergency vehicle access.
4) Public improvements flooded.
5) Property damage (i.e. landscaping, erosion, etc.)
This of course, is not to say that this heirarchy of priorities are the same
as the City of Coppell's list of priorities on any one project or situation
or at any time in history (i.e. for various conditions, the City Council may
decide otherwise).
However, since this is the general opinion of this office, and that there
were only two (2) sites reported that would involve the stormwater
collection system within the public rights-of-way, AND the flooding of
residential structures; we are recommending funding for these engineering
studies to further determine what level of funding would be needed to
resolve or improve the circumstances if, in fact, there is a reasonable,
economical or cost effective resolve to both of these sites.
Both Kevin Peiffer and I will be available at your staff meeting, and the
City Council meeting to address any questions or issues presented.
RRD/lsg
PELICNCC.
BETHEL ~CHOOI. ROAD
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CIRCLE
NORTHLAKE WOODLANDS EAST
CITY OF COPPELL,DALLAS COUNTY,TEXA~
STEVE PARSONS - I-ZI4-46Z-1665