D
I S T R I C T E N G I N E E R ‘ S R E P O R T
To: PBCSD Board
of Directors
From: Michael
Niccum, District Engineer
Subject: Fourth Priority Fire Protection
Pipeline Replacement Project
_________________________________________________________________________
It is recommended the Board of Directors approve the
scope of work for the Fire Protection Water System Improvements - Fourth
Priority Pipeline Replacement Project.
E2
Consulting Engineers (“E2”) was retained in January to perform preliminary
engineering services required to identify the costs and benefits for future
fire protection pipeline replacement projects.
E2 has reviewed fire hydrant testing procedures, updated the computer hydraulic
model of the water distribution system in Pebble Beach and prepared a technical
memorandum identifying pipeline segments with the greatest potential for
improvement and preliminary construction
cost estimates. Water main lines with calculated flows less than the
minimum fire code hydrant flow requirements were identified and prioritized for
replacement based on the ratio of existing fire flow to the fire code flow
requirements.
A
table is attached which identifies the highest priority pipeline segments and
the estimated construction cost for upgrading the pipelines. The 4th
priority segments are identified on two attached exhibits and are located in
areas where fire hydrant testing data matched the flows calculated in the
hydraulic model. Three additional
exhibits show the location of the first three pipeline improvement projects
already constructed. The proposed fourth
priority pipeline base project will upgrade the main water lines that provide fire
flow to all of the country club neighborhoods located in the gravity zone of
the water distribution system south of the Monterey Peninsula Country Club and
to the Pebble Beach neighborhood located in the first lift zone near the lower
interface with the Pescadero Canyon open space.
The optional project elements
will increase flows in the neighborhood located in the first lift reduced
pressure zone near Forest Lake and the lower interface with the Huckleberry
Hill open space as well as the neighborhood located near Bird Rock. Field hydrant test and hydraulic model data
indicate expected fire flows between 500 to 750 gallons per minute (gpm) in the
affected area and the proposed improvements will increase the flow rate above
the fire code requirement of 1,000 gpm.
Analysis
of the computer hydraulic model results and the fire hydrant testing records
indicated that in some locations a wide discrepancy exists between expected
fire hydrant flows and the actual field measurements. The reason for the discrepancy could be that
the assumed fire hydrant flows are based on old or inaccurate test data or that
pipeline friction factors assumed in the hydraulic model do not match field
conditions. The cause of the discrepancy
has not yet
been confirmed due to a delay in the 2006 fire hydrant testing program. Field testing cannot begin until the five
million gallon water storage tank located near Forest Lake is operational
following the recent California American Water (“Cal-Am”) rehabilitation project. The project elements identified for the 5th
priority base project in the summary table may change based on the results of
the fire hydrant testing.
E2 has earned $36,920 or
74 % of the budget of $49,760 for preliminary design engineering services. The remaining work includes providing
technical support services to Cal-Am and the Fire Department for the 2006 fire
hydrant testing program and revising the computer hydraulic model to reflect
the collected field data.
The information
developed during preliminary engineering indicates the proposed scope of 4th
priority pipeline improvements will provide valuable fire protection benefits to
several neighborhoods and provide additional fire flow near the interface with large
forested open spaces. It is therefore suggested
the scope of project elements identified for the 4th priority fire
protection pipeline replacement project be approved. A recommendation to approve an agreement with
E2 Consulting Engineers for engineering services required for design and
construction support could be made at the next Board meeting. It is estimated design and construction work would
be completed within twelve months. An
allocation of $1,750,000 for fire protection water system improvements is
included in the 2006-07 fiscal year budget.
C: Gary Hofsheier,
Monterey District, Cal-Am Water Company
Concur:
Agenda Item No. 13