HomeMy WebLinkAboutItem 4.06 Computerized Irrigation Systems . CITY OF DUBLIN .20
AGENDA STATEMENT
City Council Meeting Date: May 14, 1990
SUBJECT: Cost/Benefit Analysis of Computerized Irrigation
Systems
(Report by Public Works Director Lee Thompson)
EXHIBITS ATTACHED: 1) Reference list
2) Copy of report from San Diego County Office of
Education
3) Report on water saved from agencies in Southern
California
RECOMMENDATION: Receive report
2) Direct Staff to continue researching other cities
and monitoring the Shannon Park installation for
cost/benefit of computerized irrigation.
3) Direct Staff to include computerized irrigation
systems on new projects and on the renovation of
the Dublin Sports Grounds.
FINANCIAL STATEMENT: No cost associated with this report. Estimated costs
of computerized irrigation systems and estimated
irrigation cost savings are noted below.
DESCRIPTION:
As part of the Goals and Objectives for 1988, the Public Works Department was
asked to study the cost/benefit of a computerized irrigation controller
system.
OVERVIEW
Since the time of the Council's initial direction, the irrigation industry
has greatly expanded its efforts to save water and manage irrigation systems.
Computerized irrigation systems are the industry' s response to the need to
reduce water consumption in landscapes. There are basically two types:
centralized computer systems and field-controlled computer systems. Both
systems utilize moisture sensing devices to reduce water usage.
The centralized system links controllers together through receivers or
dedicated phone lines to a computer in a central location, such as an office.
All programming and monitoring is done from this central location.
A field-controlled system utilizes a computer and sensors in each controller.
This system automatically adjusts watering to achieve the optimum moisture
level for healthy plants.
The centralized system costs considerably more than a field-controlled system
and yet does not produce any better results. Therefore, the information that
follows will focus on the use of a field-controlled system.
BENEFITS
A field-controlled computer irrigation system would provide the following:
A. Efficient use of water. Moisture sensors are installed which are
linked to the controller. The sensors measure the moisture content around
- them and send this information back to the controller. The controller then
adjusts the program to stop or continue to achieve the necessary moisture
level. This is basically what a water audit accomplishes. A water audit is
a study of a particular irrigation system to achieve the most efficient use
of water. The Cities of Milpitas, Sunnyvale, Livermore, and San Ramon report
that computerized field controllers match remarkably closely with water audit
requirements.
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ITEM NO. 4#
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B. Fewer dol-_.:s expended for water usage. G_ the cities using these
units, the lowest reported reduction in consumption of water was 25%. The
highest was 35%. This percentage is the amount of water saved the first year
after installing a computerized system. The following table shows what the
City of Dublin could expect to save by using computerized controllers:
TABLE I: PROJECTED TWO-YEAR SAVINGS ON IRRIGATION WATER
25%2 USE DOLLARS SAVED DOLLARS SAVED
89-901 REDUCTION FIRST YEAR AFTER TWO YEARS
Street Medians $17,375 $13,031 $ 4,344 $ 8,688
Assess. Dists. 25,250 18,937 6,313 12,626
Parks:
Stagecoach Pk. 880 660 140 280
Kolb Park 7,450 5,587 1,863 3,726
Dolan Park 7,3503 5,512 1,838 3,676
Alamo Creek Pk. 10,000 7,500 2,500 5,000
Dub. Sports Grds. 23,500 17,625 5,875 11,750
Mape Park 1,750 1,3124 438 876
Swim Center 10,7005 9,095 1,605 3,210
Civic Centeg 3,500 2,625 875 1,750
Park System $65,130 $49,916 $15,214 $30,428
1 Projected estimate of usage ($) for 89-90 used as most accurate data.
2 Based on information from current users, minimum percentage the City can
3 expect to save.
90-91 projected cost of water at Alamo Creek Park. More representative of
4 actual costs than 89-90 figure due to construction.
Percentage saved is reduced to 15% to compensate for water other than
5 irrigation (pool usage) .
6 90-91 estimated usage because of insufficient historical data.
For purposes of this study, Shannon Park has been excluded because a
computerized controller is being installed as part of current renovation.
Over a two-year period, the total savings is over $30,000. This table uses a
25% savings factor, which may be conservative.
C. Automatic shutoff. These systems, when coupled with flow meters,
have the ability to automatically shut down when a leak or break is detected.
This ability will help in reducing wasted water due to line breaks and
vandalism. The systems can also alert the programmer to a malfunction on
each particular system so that the programmer does not waste time inspecting
stations that do not need repair. The estimated savings in labor is 10% to
15% of the irrigation maintenance budget.
D. Other benefits. Most of the computerized controllers are adaptable
to hand-held remote control units which allow the programmer to operate the
controller while physically at the site. This reduces the time it takes a
person to inspect and repair irrigation systems. Retrofitting existing
landscapes can occur with minimal damage because the wiring for the sensor is
direct burial. Most damage would occur in retrofitting street median
landscapes where new street cuts would be required. Most computerized
controllers are capable of being downloaded with a laptop P.C. and producing
very detailed report on historical use, which would be beneficial for
budgeting purposes. An example of such a report is attached.
COSTS
None of the other agencies had detailed cost estimates for installation
because their systems were either installed on a trial basis or were
specified on future projects. The field-controlled system is relatively new.
Table II includes assumptions on those costs for street median, assessment
district, and park landscapes.
-2-
TABLE II: PROJECTED COSTS TO IMPLEMENT COMPUTERIZED CONTROLLER
MATERIAL COST LABOR COST TOTAL
Street Medians $ 49,800 $ 62,4001 $ 112,200
Assessment Dists. 32,950 40,0002 72,950
Parks:
Stagecoach Park 3,050 9502 3,950
Kolb Park 3,750 1,4002 5,150
Dolan Park 7,350 2,1002 9,450
Alamo Creek Park 6,150 2,1002 8,250
Dublin Sports Grds. 5,650 2,8002 8,450
Mape Park 2,050 5602 2,610
Swim Center 3,250 1,6802 4,930
Civic Cente 10,550 2,8002 13,350
Park System $ 41,800 $ 14,390 $ 56,190
Material Cost includes each controller, sensor, flow, and so forth, necessary
to fully convert each location to computerized control.
1 Cost is derived assuming 200' of trenching at $10.00/lineal foot.
Previous work has shown a cost of $18.00/lineal foot to trench through
pavement. The lower cost is used here because of (1) the likelihood that
some existing sleeves could be utilized and (2) a large but undetermined
amount of trenching would be in landscaped areas and could be achieved at
2 a much lower cost.
Cost is based on a varying amount of manhours at each location, including
3 equipment at $35.00/hour.
Park system does not include Shannon Park.
The costs to install may certainly be higher in street median and assessment
district landscapes because of the potential for having to cut into streets
to connect landscapes. However, the cost may be significantly reduced if
existing sleeves are big enough to handle additional wire. If this is the
case, the cost to install a computerized system would be much lower. The
costs for installing in each park are conservative and reflect a worst case.
Costs may be reduced if existing conduits can be used as electrical raceways.
BENEFIT VS. COST
The table below shows the number of years needed to recoup costs based on a
worst-case scenario for installation.
TABLE III: COST VS. SAVINGS COMPARISON
SAVINGS AFTER NO. OF YRS. TO
COST TO INSTALL TWO YEARS TO RECOUP COSTS
Street Medians $ 112,200 $ 8,688 13
Assess. Dists. 72,950 12,626 11.5
Stagecoach Pk. 3,950 280 14
Kolb Park 5,150 3,726 3
Dolan Park 9,450 3,676 5.5
Alamo Creek Park 8,250 5,000 3.5
Dub. Sports Grds. 8,450 11,750 1.5
Mape Park 2,610 876 6
Swim Center 4,930 3,210 3.5
Civic Center 13,350 1,750 15.5
Only the Dublin Sports Grounds would have an almost instant benefit. It
should be noted that the Dublin Sports Grounds will use approximately 25% of
the water allocated to the park system. Additional savings could be
experienced at Kolb Park, the Swim Center, and Alamo Creek Park in the near
future. As discussed earlier, the number of years needed to recoup costs in
-3-
the street median ana assessment district landscapes could be significantly
reduced if existing sleeves could be utilized. The only way to find out is
to excavate at the ends of the medians and attempt to run a representative
number of wires through the sleeves.
CONCLUSION AND RECOMMENDATION
A computerized field controller will reduce the amount of water that the City
uses in its landscapes. That amount will vary, of course, but at least a 25%
reduction can be expected. At this time, it is difficult to determine labor
costs to install such a system. Currently, no other local agency has
retrofitted existing landscapes, but most are specifying these units in new
landscapes. Since this product is relatively new, there is no information
available as to the life of a unit. Staff recommends monitoring the system
currently being installed at Shannon Park to determine cost effectiveness and
budgeting funds to install a computerized system as part of the Dublin Sports
Grounds Renovation project. Staff additionally recommends specifying
computerized irrigation systems for future Capital Improvement Projects. A
separate project to retrofit existing systems may be recommended as a Capital
Improvement Project for a future Fiscal Year, if these systems become more
cost effective and prove to be economical from the standpoint of future repair
or replacement.
-4-
LOCAL AGENCY USE
Milpitas: Skip Evans, Maintenance Superintendent
Has a unit in one park that is 1-1/2 years old. Indicates unit tracks
very well with water audit recommendations.
Sunnyvale: Robert Walker, Superintendent of Parks
Has one installed in Cannery Park, and two additional parks will have
units installed. Experienced a 30% reduction in consumption in the
first year of use. Units tracked water audit requirements. Will send
a standard specification to us when developed.
Livermore Area Recreation & Park District: Ed Murdoch, Sr. Park
Superintendent
Has one in Hagemann Park. Tracks water audit. Estimates 20% saved in
first year at this park, and comments that the park looks better than
before.
San Ramon: Dorn Driggs, Parks Supervisor
Units installed at Athan Downs. Estimates 25% reduction in use. Units
are specified for all new landscapes, including six units in 90-91.
Very happy with results.
s. _ ��,
o
SAN DIEGO COUNTY OFFICE OF EDUCATION
WATER CONSUMPTION SAVINGS WITH CALSENSE
30
28 —
Before CALSENSE
2G —
24 — <..Learning o..�
Period
22 —
20 —
0
U)
a ro G 29% Savings with CALSENSE
V J
a 12 —
' r 10
IN G
Y
4 —
2 —
0 —
r—rrt
JAN
APR MAY JUNE JULY AUG SEPT OCT NOV DEC
14';Z
0- EDUCATION
�YPINI DEGO COUN"Y
A 0 A n A
Y—rch 23 , 1939
10 ,,THO \11 IT I-L%Y CONCERN:
The San Diego.. County' Office of Ed,icati-:n in stalled - the Calsense
Computerized Moisture Control System at our office complex .in December
of 1937 . The following are observations Dade by the landscape
deDartment and ' the office of maintenance and operations :
I
Our total water consumption , which includes landscape , lavatories and
cafeteria , is down by 29% . Since our employees have increased from year
to year , all of the reduction had to have come from landscape usage .
The m3nufacttrer of the Calsense System provides a logging capability .
According to this logging data , the savings, in landscape- usage is 35-1-13 ,
sea:
is
s s
Given the increased usage of the lavatories and cafeteria , this '
reasonable . Based on this saving , we expect to pay for the system out
0
of water cost savings in less than three years .
The reports (computer printouts) are also an excellent management tool
allowing the system to be fine-tuned and permits careful observation of
each valve in the system for water usage . This .feature also assists
greatly in budgeting for the coming year .
The service offered by the manufacturer is also a very p• s! tive feature .
Their response to problems has been very prompt and reassuring . The
company has provided on the job training to all personnel on . the
.i 0 . L.
Calsense System and has p-ro-:Ptly provided the pr_ cuts to 'e r a b le C)L:r'
irrigation department to maximize water savings ,
I am very pleased with the performance of the Calsense System and have
budgeted for an additional computer for the newest irrigation projeCt
he office complex .
covering the slopes next to the
Please give me a call at 292-3712 if Y,�u have any questions reTar'djirl-
our experience with this water conse-rvat- ion product .
Regards ,
I a A . Hansen
Manager
If,-- intenEnce and Opera tiolls
San Diego Coup O.f4ce of Educat— on
F'.
I:f L 1�.
r7W
COUIVI 0 7)
9-3, 1989
Rich u r r a y
Calsense
2075 Corte del N0931
Suite J
Carlsbad , California 92009
Dear Rich :
The Calsense System %,;as installed in December of 19317 as result 0 4L
Z of Education durinc-
testing perforred here at the San Diego Ccuntv
the previous 5 months . After one fear of experience with the model - 1000
-ed . This is
7� system, an approximate 356 reduction in water usage 0 c�_U r r - L al
summary and t;zl--, r1c, into account
1. based c.n the attached water bill sumL I - S
consumption . We recently upgraded the model 10-00
lavatory and cafeteria con 0 - U I t%- ,
-
to the model 2000 . 'Listed below are my obs'ervations in ma4nt`iR._' n`
Calsense System :
ns-a
the Calse,
The ease of c Deration 1,,ave been able to P- oc�'r3
Tn .,-i t h t,,-o
ng t h;e r--a u a t h-3 p
2000 t 3-0 U t r e adi
i t was nece_zsary to r c e
different contrOl
lei CO'__'P;=n4Os , to
in orz; er -
.3sistence fro:2. the ianufa�:tl:r =rs
their controllers .
eXCel' eL
L sincle phcne Call Ss
The e factory =eryjce has be=-,I n' -
immediate help .
3 . Spnc; al features allOws the Calsen_-e to
trouble shooter . It even has ow Sens:L-3 --,�-hich turns f f
v a ve when a szrirkler head breaks
4 . I h-3ve a lot Of t i e b e c a u s e it 1s no I n c e r n°_ e s 45 r
a
t a f r e ri e n t c C.c k C h a S e S 7) C: -2 u e t 0 r L1
n the weather-r .
C.
T:'r. Rich ?•lurray - 2
tiarch 23, 1989
i
S . We will have the Calsense System paid for our of our water
savings in less than three years .
I will pe happy to show the Calsens*e System to any of your potential
Qustomers .
Sin e el y,
r
Jack O' Lexey
Head Grounds YK-eer
p
San Diego County Office of Education
6401 Linda Vista Road '
San Diego , California 92111
( 619)292-3721 '
}
Froject : San Diego County School Board ;
DATES 1.1AX TIME ACTUAL TIME PERCENT PERCENT
USED SAVED
TOTALS 34834 18912 54% 46%
Sept 16-Nov 7 9255 6196 67% 33%
Jul 13-Sept 7 9175 6543 71% 29%
Apr 27-114ay 16 4320 1005 23% 77%
Mar 18-Apr 6 3816 1902 500 50%
Feb 24-Mar 16 1163 671 580 42%
Dec 17-Jan 31-1989 7105 2595 37% 63%
20, dd. A.L'c 0
PROJECT SAN DIE,J9 COUNTY S•C=COL B.',)-'.PD =2
DATES TI''1E ACTUAL T'I^1E PERCENT PERCEirT
USED SAVED
TOTALS 21231 14411 680 320
SEPT 14 - NOV 11 5573 3763 66%. 34"0
JULY 13 - SEPT 7 6013 4665 78% 21'
JUNE 13 - JULY 11 3495 2561 73% 27%
APRIL 27 - ;1AY 8 633 353 56 444
MARCH 25 - APRIL 4 1089 531 490 510
FEBRUARY 24 - MARCH' 13 1089 421 390 61,`
FEB 3 - FEB 15 614 435 79` 2
Nov 13-Feb 10-1989 2625 1632 62% 381=0
Z-1 =,
C L V ♦ ! [
PROJECT SAN DIEGO COUNTY SCHOOL BOARD r3
DATES ViAX TIME ACTUAL TIME PERCENT PERCENT
USED SAVED
TOTALS 48728 34123 709 309
8119 7209
89 0
119
OCT 2 - NOV 13 25y,
JUL 13 - SEP 2 13169 9845 759
APR 27 - MAY 16 6088 1703 289 729
APR 6 - APR 14 2.771 2450 889 129
APR 3 - APR 5 961 934 979 39
MARCH 25 - MARCH 27 1459 1069 739 27A
FEB 24 - MAR 14 4629 2115 469 549
2583 799 21
3268 0
FEB 3 - FEB 15
Dec 5-Jan 30-1989 8264 6215 759 259
2G%5 Corta de:Nr ga'.Sulte J Car.Szad.Cis.920='S, 9j 9,r-- -33.0-?
M u N I A \_
Fi O.iELT SAN DIEGO COUNTY SCHOOL BOARD r4
D"%TES MAX TI?:E ACTUAL TIME PERCENT PERCENT
USED SAVED
TOTALS 59973 29254 497 51%
S 2,FT 22g .. p;OV 13 11867 7224 61"
I.:L. L •O
JUL 18 - SEPT 7 11003vSIO 62 3S
APR 27 - MAY 16 0347 2177 aY o 65
"'IARCq 25 - APR 5 4023 2540 63" 37 o
FEB 24 -- MARCH 14 5136 2542 49 51Cr
FEB 3 - FEB 15 3021 1369 457 55'74
Dec 4-Jan 30-1939 9285 3296 350 b5o
SIN DIEGO COUNTY OFFICE.. OF EDUCATION PAYB':C"r; ANALYSIS
PERIOD HCFT WATER BASE SEWER C"`ST SEWER
US7-D PATE /i.CF /H Cr
350
4-5/5-6 099 654 . 96 321 . 32 515 .80 0 .935995 0 . 237281 1
5-6/6/8 784 734 . 61 321 .32 57,8 . 59 0 . 937002 0 . 291568 1
6-6/7-7 783 733 . 67 321 .32 613 .66 0 . 936998.. 0 .336730 1
7-7/8-9 924 865 . 79 321 . 32 836 . 12 0 . 937002 0.580216 1
8-9/9/8 905 847 . 99 321 . 32 867 . 9 0 . 937005 0.572265. 1
9-8/10-3 1056 989 . 47 396 .3 1012 . 7 0 . 936998 0 .627556 1
o14 575 . 32 321 . 32 588 .83 0 . 937003 0 .385973 . 1
11-7/12-7 406 330 . 42 321 . 32 584 . 23 0 . 936995 0 . 576921 1
12-7/1-6 373 350 . 93 321 . 32 536 . 75 0 . 940831 0 .500670 1
WATER USED PREV T CF/ °10 THIS ECF/1,10
JAN 10846 450 16214 672
rEB 15943 597 1700 0 636
MAR 19572 811 16866 699
APR 21340 856 17770 713
JUNE 21932 880 '01:� 810
JULY 27832 1156 209= 4 868
AUG 21404 1136 22564 935
SEPT 24737 992 21348 656
OCT 2!73- 1�?25 1°37C 761
?;OV 2200 82 I .. 1 '_2 406
DEC 21000 870 9:00 4C6
JAN 19729 818 9=00 385
FEB
APR-.IAN 8614
SAVINGS APP,-J N,' 2474
SAYINGS Et.R:.LOT,ATED 2 C68
'vr!.TER P i.TE 0 . 937
SAVINGS k': . CR Y2 , 7oi
SA 1•T J*(-S S_
rJTAL JaVIN0S �3 f 672
Y
COST Or SYSTEM $8 , 056
PAYBACK 2 . 194093
. .'. :3.--.CK A ER 0?N'TY 2 , cc`�;?8
0= CALSENSff
C A " .O A N i n S E N S O R C C A A O P�T i O N
PROJECT Yorba Linda Park-Anaheim
DATES MAX TIME ACTUAL TIME PERCENT PERCENT
USED SAVED
TOTALS 61326 53045 86% 14%
July 26-Aug 23 13838 13303 96% 4%
June 9-July 12 13211 11192 85% 15%
May 24-June 7 6662 4206 63% 37%
;iay 1-May 21 8550 6101 71% 29%
Sept 10-Oct 12 12625 12625 100% 0%
Oct 12-Nov 11 4735 4344 92% 8%
Nov 13-Dec 18 1705 1274 75% 25%
Sept 10-Oct 12 the set points were too high causing 100% irrigation
October 12-Nov 11 the system was inadvertently put into the
emergency mode causing 100% irrigation during that period .
2075 Corte del Nogal,Suite J.Carlsbad,CA.92009 (619)438.0525
0-2:7
A F O R N 1 A S E N S O R C O R P O R A T I O N
PROJECT Victoria Grove Park , Rancho Cucamonga
DATES MAX TIME ACTUAL TIME PERCENT PERCENT
USED SAVED
TOTALS 68502 56398 82% 18%
Dec 18-Dec 28
Dec 29-Jan 11 2751 1913 70% 30%
Dec 08-Dec 16
Dec 18-Jan 11 2207 2272 103% -3%
Jan 12-Feb 03 5017 2950 59% 41%
Dec 30-Jan 03 5058 2231 44% 56%
Feb 04-Mar 15 10420 6552 63% 37%
Jun 12-Jul 17 18257 18193 100% 0%
Sep 16-Nov 06 7242 7242 100% 0%
Sep 25-Nov 06 17550 15045 86% 14%
2075 Corte del Nogal,Suite J.Carlsbad.CA.92009 (619)438.0525
o 7
S E N S O R c O A A O A A t i O N
Project : Cuyamaca College
DATES MAX TIME ACTUAL TIME PERCENT PERCENT
USED SAVED
TOTALS 6342 5235 83% 17%
Mar 1-May 14 3234 2547 79% 21%
Mar 24-Apr 9 3108 2688 87% 13%
2075 Corte del Nogal,Suite J,Carlsbad,CA.92009 (619)438-0525
L7 CAISIENS
C o F O A N 1 A S E N S O R C O Ia A O a n T 1 0
PROJECT Central Pk ; County of L.A ; Valencia
DATES MAX TIME ACTUAL TIME PERCENT PERCENT
USED SAVED
TOTALS 104259 58124 56% 44%
Apr 14-Apr 19 5270 478 9% 91%
May 10-May 23 10653 6680 63% 37%
May 24-Jun 21 25954 14873 57% 43%
Dec 21-Jan 25 19582 3708 19% 81%
Mar 15-Mar 25 8609 3656 42% 58%
Dec 03-Dec 15
Apr 28-May 09 9445 3795 40% 60%
Jun 22-Jul 19 24746 24934 101% -1%
2075 Corte del Nogal.Suite J,Carlsbad,CA.92009 (619)438-0525
r7 'CY
p F O R N l p S E N S O R C O R P O P A T I O N
PROJECT Las Ventanas , Valencia ; Controller A
DATES MAX TIME ACTUAL TIME PERCENT PERCENT
USED SAVED
TOTALS 22187 17665 80% 20%
Mar 29-Apr 04 590 590 100% 0%
Apr 14-Apr 26 2162 2047 95% 5%
Apr 28-May 30 3892 3871 99% 1%
May 24-June 20 4061 2048 50% 50%
June 21-July 23 4737 3927 83% 17%
July 24-Sep 13 6745 5182 77% 23%
2075 Corte del Nogal,Suite J.Carlsbad.CA.92009 (619)438-0525