ST0301A-AG100727 (2)T H E C I T Y O F
AGENDA REQUEST FORM COPPELL
T DATE: July 27, 2010
A s �
ITEM #: ES - 3
WORK SESSION
0
in
Discussion regarding the November 2nd Election.
Discussion regarding Aerial Sewer Crossing.
Discussion regarding City participation for maintenance and electric costs
associated with lighting along S.H. 121.
Discussion of Agenda Items.
Agenda Request Form - Revised 02/07 %wksessn
MEMORANDUM
TO: Mayor and City Council
FROM: Kenneth M. Griffin, P.E., Director of Engineering/Public Works
DATE: July 27, 2010
REF: Discussion concerning a proposed change order associated with Bethel Road
ST 03 -01A from Penfolds to Denton Tap.
During the course of the removal and replacement of the existing bridge along Denton Creek on
Bethel Road, an opportunity has presented itself that would eliminate an ongoing maintenance
issue for the City of Coppell.
The main trunk sewer line along Bethel Road utilizes a siphon system as it crosses Grapevine
Creek. In essence, a properly working siphon system allows the sewer line to be constructed
down one bank, below the creek bed and back up the other bank and then continue into a gravity
system. With a correctly operational siphon system, you do create those rare situations where
sewage does flow uphill. We do have other siphon systems in town that work correctly;
however, this particular system along Bethel Road has been an ongoing maintenance issue since
it was constructed in the mid -90's.
Because of the removal of the bridge, we have an opportunity to drill several additional piers
adjacent to the bridge and construct and aerial crossing that would eliminate the existing siphon.
The design of the aerial crossing has been performed in house by Keith Marvin, P.E., Project
Engineer; however, the negotiations with the contractor are not yet complete.
To continue moving forward with the project, we need to move forward with the drilling of the
piers prior to additional work taking place on the bridge structure. Based on initial discussions
with the contractor utilizing the preliminary plans, it's anticipated this change order will cost
between $90,000.00 and $100,000.00.
Staff is seeking general consensus to move ahead with the removal of the siphon and the
installation of an aerial sewer crossing, with a change order to follow potentially at the August
24 Council meeting.
Staff will be available to answer any questions at the Council meeting.
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