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August 2017
8-4
City of Morgan Hill
Sewer System Master Plan
8.2.4
Construction Contingency Allowance
Knowledge about site-specific conditions for each proposed project is limited at the master
planning stage; therefore, construction contingencies were used. The estimated construction
costs in this master plan include a
30 percent
contingency allowance to account for unforeseen
events and unknown field conditions.
8.2.5
Project Related Costs
The capital improvement costs also account for project-related costs, comprising of engineering
design, project administration (developer and City staff), construction management and
inspection, and legal costs. The project related costs in this master plan were estimated by
applying an additional
30 percent
to the estimated construction costs.
8.3 CAPITAL IMPROVEMENT PROGRAM
The Capacity Improvement Costs for the previously identified projects in this master plan for
mitigating existing system deficiencies and for serving anticipated future growth throughout the
City are summarized on
Table 8.2
. The Capital Improvement Program lists the type of
improvement, location, cost, construction trigger, suggested phasing, and cost sharing.
8.3.1
Pipelines
The recommended pipeline improvements are grouped by collection basin and listed on
Table
8.2
. Each improvement includes a general description of the street alignment and limits as well as
existing pipe diameter and length.
The following three pipeline improvements categories were identified:
x
New Pipeline.
The new pipeline is proposed where none exists.
x
Replacement Pipeline.
This improvement is intended as a replacement to an existing
pipeline and along the same alignment. The existing pipeline should be abandoned when
the replacement pipeline has been constructed.
x
Parallel Pipeline.
This improvement is intended as a parallel to an existing pipeline. The
existing pipeline should remain in service, even when this new improvement is
constructed.
The opinion of probable construction costs, for the projects included in this master plan, are based
on the pipe unit costs summarized on
Table 8.1
.
It is assumed that any replacement pipes will be in the same alignment and at the same slope as
the existing pipe. However, this study recommends an investigation of the alignment during the
pre-design stage of each project.