HomeMy WebLinkAboutNB 2 FOOTHILL RESER 11-07-88'" "~"': ~'~'"'~"' FL ~ "~- ,~ NEW B US I NESS
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DATE: OC~O~a 3~, ~~988 ~ I
TO:
WILLIAM HUSTON, CITY MANAGER
FROM: PUBLIC WORKS DEPARTMENT/ENGINEERING DIVISION
SUBJECT: FOOTHILL RESERVOIR REPAIRS
RECOMMENDATION:
That the Tustin City Council at their meeting of November 7, 1988
authorize staff to complete the following:
1. Solicitation and selection of a consultant to evaluate, test and
recommend the required remedial measures for the Foothill
Reservoir repair.
2. Solicitation of competitive bids for required Foothill Reservoir
repairs.
and the authorization of a supplemental budget appropriation of $32,500
for fiscal year 1988-89 in the Water Enterprise Fund.
BACKGROUND:
The attached memorandum outlines the problems which the City has
encountered and the initial phases the staff recommends towards the
required repairs on the Foothill Reservoir facility. As indicated in
the memo the time available for identifying the problem, its location
and to quantify it is very limited during the traditional winter/wet
season. Consequently, staff is requesting authorization for the
following items:
a. Solicitation and selection of a consultant to evaluate, test and
recommend the required remedial measures for the reservoir
repair.
b. Soli.citation of bids for required reservoir repairs.
c. Supplemental budget appropriation in the amount of $32,500 for
fiscal year 1988-89 for said reservoir repairs.
-Bob Led[end~cker
Director Public Works/City Engineer
TO:
FROM:
SUBJECT:
,
Bob Ledendecker, Director of Public Works/City Engineer
Pabio Rodriguez, Manager Field Services
Foothill Reservoir
Foothill Reservoir is a 3.5 MG Facility locate at Fowler and Hewes in the unincorporated
area of the County. The reservoir has an overflow elevation of 326' with operating depth
of 26'-0'.
The reservoir was constructed by by Tustin Water Works forces in 1958. The
construction method consisted of steel reinforced columns which were poured in place, a
reinforced concrete slap roof and gunite walls which utilize a I 1/2' - 1' slope.
Historically, this reservoir has been operated at water level of approximately 18'. It is
primarily used to balance well production and imported water take-outs within the 300
HGL pressure zone.
During the summer of 1988, we received a complaint of water infiltrating through the
garage walls of a dwelling at 18771 Winnwood, located directly downstream of the °
reservoir. We verified that the level of the reservoir at the time was 24 feet. We
immediately started to draw the reservoir down and were notified that the infiltrating
ceased at 18'. The reservoir was drained down to 16' and stabilized for approximately
two weeks. At that time the reservoir level was increased slowly. At approximately
20-21' the infiltration reoccurred. We dropped the reservoir level to approximately
16 feet, and are currently maintaining that level.
I have discussed this problem with people who have recently had similar problems and
have been involved in alternative solutions to reservoir seepage.
The consensus is that we should use a three step approach to detail final resolution of the
remedial repairs.
.
Identify the problem, its location and quantify it. Is the reservoir
leaking? Where is it leaking? and how much is it leaking?
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Identify the condition of the reservoir. This would involve a
total draw-down, visual inspection and necessary structural
investigations of the concrete and. steel components.
Selection of alternative methods available for remedial repairs.
This could involve coatings, liners, caulking and/or other methods.
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· Foothill Reservoir
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In order to address this problem in a timely fashion, its imperative that we set forth a
schedule of.required activities which will allow is to address a solution to this problem
in a manner.which least impacts the operation of the Water System.
I would recommend that this project be given a high priority, assigned to Engineering to
develop a RFP to address the remedial scope of work. That the work be phased in such a
manner as to keep the reservoir in service during critical months of the year.
A standard liner installation is estimated to cost $1.00/sq ft or $25,000.00. Assuming
preliminary and final engineering cost to be approximately 30% of the construction
cost, or $7,500.00, the total cost is estimated to be $32,500.00.
'Pablo - ~
'Rodriguez
Manager Field Services
Attachment: Plans (4) sheets
P. Murphy
G. Veeh
Ron Wolford
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