HomeMy WebLinkAboutAGENDA REPORT 1994 0202 CC REG ITEM 08C ITEM
AGENDA REPORT
C=TY O F MOORPARI‹
TO: The Honorable City Council oo^'A.rt< ct'
FROM: Kenneth C. Gilbert, Director of Public Works (C f199
ACTION. a ���
DATE: January 25, 1994 (Council Meeting 2-2-94) /"y"
SUBJECT: Consider Approval of a Project to Drill a New Irrig.t. . if
Well at Arroyo Vista Community Park , Mt"C,
BACKGROUND
As you are aware, the Arroyo Vista Community Park property was
granted to the City by Urban West Communities (UWC) in order to
fulfill certain obligations related to their development
entitlements. That property had been previously been used for
agricultural purposes. Those uses were supported by two water
wells on the property. Those water wells became the property of
the City along with the land.
As a function of the development of the park property, the City
directed the landscape architect to design an irrigation system
which was to use these wells as the source for park irrigation
water for the park. That design was prepared and the project was
constructed using these water wells.
The subject water wells were constructed more than thirty (30)
years ago. It was known when the City first embarked on the
project design that the condition of the wells was questionable.
It was suspected that, as a minimum, the pump motors and related
equipment would have to be replaced.
In July of 1993 the City Council authorize staff to proceed with a
project to investigate and evaluate the condition of the easterly
of the two water wells. That effort is generally described as
follows:
■ Pull the well column pipe and inspect same.
■ Perform a television inspection of the well casing.
Provide a general description of the condition of the well,
including the depth of the well and the depth of the water
level in the well;
■ Provide a general description of the condition of the well
pump components.
■ Develop a profile of the required pumping characteristics
(pressure, flow rate, drawdown, etc. )
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■ Develop and provide recommendations regarding the following:
• the conditions of the well casing and the method to be
used, if any, to clean same (chemical, blasting, brushing,
etc. ) ;
• the method to be used to remove the debris from the well
produced by cleaning or other sources;
• the type of well motor replacement; and,
• specifications for all of the above.
Staff retained a qualified firm to perform this work. The results
of that analysis is discussed below.
DISCUSSION
A. Water Cost Comparison
The primary purpose for using the on-site water wells is cost
effectiveness. A comparison of the estimated cost of well water
and domestic water is summarized as follows:
Domestic Water City Water
Description Service Costs ($) Well Costs ($)
Calleguas Municipal Water 70,000 0
District Connection Fees
Water Works District #1 19,000 0
Capital Connection fees
Water meter installation 1,500 0
charges
Water usage per year 30 ,000 1,000
Phase I (33 acres)
Water usage per year 60 ,000 2,000
Total Park (69 acres)
Water well maintenance 0 1,000
and operation (electrical
energy, oil, etc. )
B. Water Quality
The water extracted from the water wells on-site measures high
in Boron and is, therefore, not suitable for use as drinking
water. The amount of Boron content is at the upper limits of
the range which can be tolerated by plants. This condition was
known during the development of the project design. The
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Landscape Architect has stated that this water source is
suitable for the irrigation of the park. The species of plants
included in the project design were selected for their ability
to tolerate irrigation water with a high level of mineral
content. It was the opinion of the Landscape Architect that
there will be no adverse effect from the long term use of this
water source for park landscape irrigation.
C. East Well Evaluation
As stated in the Background of this report, a qualified water
well maintenance and service company was retained to investigate
and evaluate the condition of the east well. The findings from
that investigation are summarized as follows:
• TV Inspection: The interior of the well was inspected via a
remote controlled TV camera.
• Well: The depth of the well was found to be slightly more
than two hundred feet (200' ) . The static water level was
found to be approximately twenty-five feet (25' ) deep.
Although there is evidence of encrustation on the well
casing, the well casing and casing perforations were found to
be in fair condition. There was evidence of debris at the
bottom of the well .
• Pump: The well column pipe and related equipment were found
to be in a state of severe deterioration. The column pipe
could not be disassembled due to severe rust and corrosion
and had to be cut to be removed.
D. Results of Well Investigation
Based on the above findings, the contractor provided the City
with a report which basically describes two options --
rehabilitation or replacement. Those options are briefly
described as follows:
1 . Well Rehabilitation -- A contract to rehabilitate the
existing east well would include the following tasks:
a) Bailing -- the removal of the materials on the bottom of
the well (optional) ;
b) Relining -- the installation of a new eight inch (8")
column pipe inside the existing twelve inch (12") column
pipe;
c) Packing -- the installation of rock material between the
existing and the new column pipes;
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d) Cleaning -- the cleaning of the perforations in the
existing column pipe by means of explosive charges;
e) Testing -- the installation of a temporary pump to test
the flow rate characteristics of the rehabilitated well.
The estimated cost of the construction of this option is
$20,000 to $25,000. It should be noted that although it is
anticipated the ground water extraction rate of the
rehabilitated well would be equal to or greater than that now
demonstrated by the west well, staff is advised that a
contractor would not be able to guarantee this result.
2 . Drilling a New Well -- It is anticipated that a set of
"boilerplate" plans and specs could be obtained from
qualified well drilling contractors. The estimated cost to
drill a new well is $40,000.
E. Cost Comparison
It should be noted that either of the above two options would
require the installation of a new submersible well pump and
motor for an additional expenditure of $20,000±. A comparison
of the estimated total project cost for these two options is as
follows:
Rehab Existing Drill New
Item Well ($) Well ($)
Design 1,000 4,000
Rehab Existing Well 25,000
Drill New Well 40 ,000
Cap Existing Well 5,000
Inspection 4,000 4,000
New Well Pump and Motor 20,000 20 ,000
Total 50 ,000 73 ,000
F. Committee Review
At a recent meeting of the Public Works, Facilities and Solid
Waste Committee (Councilmembers Wozniak and Montgomery) the
Committee discussed these proposed improvements.
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G. Recommended Option
Staff and the Public Works, Facilities and Solid Waste Committee
recommend that a new water well be drilled. This recommendation
is based on the following list of perceived benefits:
• all of the well components would be new;
• the diameter of the well would be a full twelve inches (12" ) ;
• the well casing perforations would be new and thus not
blocked by infiltration and corrosion; and
• the groundwater extraction rate has the potential of being
superior to that of a rehabilitated well.
A contractor will guarantee that the well is drilled properly
and the equipment will work properly. However, a contractor
will not guarantee groundwater production rates. There is a
certain degree of risk involved in the drilling of any water
well. Nevertheless, for the reasons stated above, it is the
view of staff that the chances of a failure of a new well are
far less than the chances of a failure of a rehabilitated well.
In addition, in that the potential for groundwater production is
more a function of the condition of the underground aquifer than
the actual well, and it is already known that there is a
"healthy" aquifer in this area, it is the view of staff that the
chance for failure are extremely remote.
H. West Well
The age of the west well is approximately the same as that of
the east well. Based on the findings from the inspection of the
east well, it is not recommended that any additional funds be
expended to inspect and evaluate the condition of the west well.
It is recommended that the west well be used in its present
condition as the primary well until the new well is drilled and
place on line. The west well could then be used as the back-up
well and, at some point in the future, it too should be
replaced.
I. Fiscal Impact
Staff is in the process of developing an updated cost summary
for the Arroyo Vista Community Park development project. The
cost to substantially upgrade or replace one or both of the
irrigation wells was not included in the list of tasks
identified in the cost estimate previously presented to the
Committee and the City Council. It is anticipated that it will
not be possible to fund these well improvements with surplus
construction monies, but rather an additional appropriation
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will be required. Nevertheless, it is recommended that the City
Council authorize staff to proceed with the preparation of a
design for this project, using funds already appropriated for
park improvements, and defer the appropriation of additional
funds for construction until the project design is completed and
a more accurate cost estimate is available.
J. Conclusion
Again, the water wells on site are in poor condition. It is
recommended that the City proceed immediately with the
construction of a new well in order to provide a long-term,
reliable, inexpensive source of irrigation water for this park.
RECOMMENDATION
Staff and the Public Works, Facilities and Solid Waste Committee
recommend that the City Council direct staff to proceed with
efforts necessary to develop a design for the drilling of a new
irrigation water well to replace the east well at Arroyo Vista
Community Park, for a cost not to exceed $4,000 [Note: No
appropriation or budget amendment is required] .
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