DR9101-CS 910710 (2)July 10, 1991
MS. Shohre Daneshmand, P.E.
City of Coppell
Post Office Box 478
Coppell, Texas 75019
Re: Oak Trail Drainage Project
Dear Ms. Daneshmand:
I~_.,nazo, Starek & Tang, Inc.
Engineers · Planners
This is to further discuss the options available to the
city to resolve the known utility conflict described in our
letter to you on July 8, 1991. In that letter we discussed
the possible solution of lowering the water line to clear
the proposed storm sewer. The contractor, M-S Utilities,
has submitted a proposal of $3,669.60 for this work.
Another possibility is to put the water line through the
storm sewer by using ductile iron pipe and a steel sleeve
for the water line. The contractor will do this work for
$500. The consequences of implementing this solution are
that during the 100-year storm the level of the water
accumulated in the backyard of 141 Oak Trail would be about
0.75 feet higher, and it would take approximately 5 minutes
longer to completely drain.
Also discussed in the July 8 letter is the potential for a
second conflict. After reviewing the proposed plan
profile, we feel there is a good possibility that the
second conflict will be avoided when it is uncovered in the
field. The top of the storm sewer at that point is over
6 feet below grade, and most water laterals are placed
about 4 feet deep.
A summary of options follows:
For known conflict Point
Lower water line using contractor at a cost of $3669.60
or city forces for a materials cost of approximately
$1000. Hydraulically the storm sewer would be un-
affected.
330 Union Station
Da0as, Texas 75202-4802
214/748-6740 Metro 214/263-5420
Fax 214/748-7037
Ms. Shohre Daneshmand, P.E.
July 10, 1991
Page 2
Put the water line through the 42-inch storm sewer pipe
using ductile iron water pipe and a steel sleeve using
the contractor at a cost of $500. During the 100-year
storm, this would cause the water in the backyard of
141 Oak Trail to be 0.75 feet deeper, and it would take
5 minutes longer to completely drain.
For second (potential% conflict Point
There is a good possibility that this conflict will not
exist when uncovered. If it does, the conflict would be in
the upper portion of the storm sewer, and we would recom-
mend using the $500 solution as described earlier.
As we discussed, the contractor needs a decision by this
Friday, July 12, 1991, or an additional $1000 expense will
be incurred due to the removal of his equipment from the
site.
If you need any additional information about this situa-
tion, please let us know.
Sincerely,
Glenn Hit P.E.
Vice President
GH/smh
89256.20