Big Gulch Sewer Line Replacement
 Over the last six years, the District has been
involved in efforts to address the impacts of
uncontrolled stormwater on the sewer lines that
follow the length of Big Gulch into the District’s
Wastewater Treatment Plant.
Since emergency repairs
were done in December 2006, the Big Gulch Sanitary
Sewer Reconstruction Project has constructed a
stormwater headworks structure and a high flow
bypass line. Construction has also been completed on
a new sanitary sewer pipeline, an additional line
for future needs, and the restoration of the stream
and adjacent areas in the upper sections of the Big
Gulch drainage basin.
The construction contract to
move the lower reaches of the sewer line away from
the impacts of the creek has recently been awarded,
and work has begun. As designed, the new line will
be directionally drilled and placed in a small bore
tunnel almost 2,500 feet in length. This new
pipeline will extend downstream to the wastewater
treatment plant access road where it will be
connected into the existing pipeline which flows
into the treatment plant. The horizontal directional
drilling technique minimizes environmental damages
by drilling the pipeline underground and going
beneath the sensitive areas.
We expect construction
of this segment of the project to be completed by
the end of the summer. Completion of the entire
project is expected by the end of 2009. The final
phase of the project includes replacing the bridge
at the bottom of Big Gulch, which is the access
route to the wastewater treatment plant.
The Big
Gulch sewer trunk line carries approximately 80% of
the wastewater generated within the City of
Mukilteo. The District has worked with the City of
Mukilteo and various state and federal agencies to
implement this very difficult and complex repair
project to a major piece of public infrastructure,
and we will continue to work to protect the sewer
line and the Gulch.
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