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CITY OF PALM DESERT
PUBLIC WORKS DEPARTMENT
STAFF REPORT
REQUEST: Authorize Staff to Proceed with the Bidding Process for the
Purchase of Irrigation Equipment to Convert Solar and Standard
Controllers to "Smart" Capability.
SUBMITTED BY: Mark Greenwood, P.E., Director of Public Works
DATE: June 11, 2009
Recommendation:
By Minute Motion, authorize staff to proceed with the bidding process for
the purchase of irrigation equipment that will convert solar and standard
irrigation controllers to "Smart" capability, not to exceed $54,000.
Funds are available in General Fund Account No. 110-4614-453-3915, Special
Programs -Water Conservation and Capital Reserve Fund Account No. 400-4645-433-
4001.
Executive Summary:
The majority of the irrigation controllers in the landscape areas that are managed by the
Landscape Services Division of the Public Works Department do not have the capacity
to automatically adjust irrigation schedules based on the plant water needs or changes
in weather ("Smart" capability). In order to conserve water, maximize efficiency of staff
time, and provide optimum growing conditions for these landscapes, staff is requesting
to purchase irrigation equipment that will convert existing irrigation controllers to "Smart"
status.
Staff Report —
Irrigation Equipment
Page 2 of 3
June 11, 2009
Discussion:
The Public Works Department's Landscape Services Division manages a total of 173
irrigation controllers; 131 are solar powered and 42 are standard 110 volt power. Only
eight have "Smart" capability, which is the ability to automatically adjust irrigation
scheduling based on present weather conditions or plant water needs.
The solar controllers, due to their unique character, are not compatible with any
available weather -based scheduling device. However, they can be connected to sensor
devices such as a rain shutoff switch, or a soil moisture sensor. Soil moisture sensors
schedule irrigation based on plant water needs rather than weather conditions. In the
past two years, staff has field tested the combination of the solar controller and a soil
moisture sensor with positive results. The approximate cost for the conversion of 131
solar controllers is $310 per controller ($40,610), which is far less than the cost of a new
"Smart" controller.
The standard irrigation controllers can be retrofitted to "Smart" status with the
installation of an available weather -based scheduling device, which works with the
existing irrigation controller to provide "Smart" capabilities, or by completely replacing it
with a new "Smart" controller. Staff will install the device that is least expensive. The
approximate average cost per conversion is $385 for a total cost of $13,090.
The total estimated cost for the conversion of all the controllers is $53,700.
In addition, staff has contacted the Coachella Valley Water District (CVWD), who has
participated in a "Smart" irrigation conversion program with the City of Indian Wells, and
they have indicated their willingness to participate in a similar program with the City of
Palm Desert. Staff understands that CVWD's participation would be 50% of equipment
cost.
The installation of these devices will be done by City Landscape Services staff. The
recurring maintenance cost for the equipment is null for the regular controller and the
yearly replacement of a 9-volt battery for the solar controllers.
Therefore, staff recommends that City Council, by Minute Motion, authorize staff to
proceed with the bidding process for the purchase of irrigation equipment that will
convert solar and standard irrigation controllers to "Smart" capability, not to exceed
$54,000.
Staff Report —
Irrigation Equipment
Page 3 of 3
June 11, 2009
Fiscal Impact: Landscape Services Division's estimated cost for water usage in Fiscal
Year 2008-09 is $112,000. The use of a "Smart" controller has demonstrated a 15-25%
savings. This translates into an annual savings of $16,800 to $28,000. The recovery
cost for this investment will be between 1.9 and 3.2 years without CVWD's contribution,
and 1.1 to 1.7 year with their participation. There is a potential for greater savings now
that CVWD has instituted tiered water rates. Funds are available in Special Programs
Account No. 110-4614-453-3915 and Capital Reserve Fund 400-4645-433-4001.
Prepared By:
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Approval:
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Jo ►''� . Wohlmuth
C Manager
ent Services
Department
Mark Gr4nwood, P.E.
Director of Public Works
Paul Gibson
Finance Director
CITY COUNCIL ACTION
APPROVED * ✓ .DENIED
RECEIVED OT4IER
MEETING DATE /2-/)-b9
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ABSENT: e
ABSTAIN: AI O41 e.
VERIFIED BY: K_I (ei
Original on File with City Clerk's Office
*Removed for separate consideration -then approved,
with an increase of $20,000 for the purchase of
additional equipment as part of the Smart Router
Meter Program. 5-0
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