Evaluation of Weather-sensing Irrigation Controllers
Contents
1. Assessment of Interface and Setup csse seen Weather Parameters Employed and Programming Procedures Required Evaluation of Irrigation Schedul s eee eee eere herren nhe rrt SUMMARY AND CONCLUSIONS so e lebt Sr EpL ETE ert bra TABLES Table 1 Features of weather sensing irrigation controllers evaluated Table 2 Number of irrigation days per week scheduled by three weather sensing irrigation controllers for five landscape FIGURES Figure 1 Weather sensing irrigation controllers Figure 2 Irrigation applied by an Aqua Conserve controller compared to ETo and UCR references for 3 landscape Figure 3 Irrigation applied by a WeatherSet controller compared to ETo and UCR references for 3 landscape Figure 4 Irrigation applied by a WeatherTRAK controller compared to ETo UCR references for 3 landscape Figure 5 Irrigation applied by a WeatherTRAK controller at mixed high and mixed low water use plants settings compared to LITBRATURELITPBDL sa asesebrvuns D Pitteng2. Trees Shrubs 250 H ETo z BETo a E Aqua 2 m 2 2 Annual Flowers 300 250 E 200 ElHistoric ETo BETo E Bl Aqua 3 m 2 BO a Sg of FESS SF SF e D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 20 Evaluation of Weather sensing Landscape Irrigation Controllers Figure 3 Irrigation applied by a WeatherSet controller compared to ETo and UCR references for 3 landscape treatments in 2003 at University of California Riverside 25 4 mm 1 in Cool Season Turfgrass 3 E E ElHistoric ETo z BETo Bil WeatherSet 1 3 LUCR 1 S Trees Shrubs 200 150 ElHistoric ETo BETo E WeatherSet 2 100 OUCR 2 Water Depth mm 50 4 0 T T T T T S A DL HD HN DP DM OG qd H Bg PO AO APP SP Ost PMP OP P i S Ow VOS C LS KY 8 HK HK GS 9 KF LLM Kw Y b S ow qd SA SU S SN F F S FF qq 9 Annual Flowers 250 200 E m Historic ETo BETo E Bl WeatherSet 3 5 OUCR3 c z D a e m P S J gg os x M SS S D q sj S es 9 gU ON sE J D Pittenge
3. 2003 at University of California Riverside 25 4 mm 1 in Mixed High Water Use Plants 200 ElHistoric ETo E E 150 z BETO o a xe 1004 E Weather TRAK 4 50 4 KS J n ra rd xv SUO S E E SQ S N SU S il C lt Mixed Low Water Use Plants 250 200 E Historic ETo E 1504 z BETO a 100 4 Bl Weather TRAK 5 0 r N D D 5 M KO O m P P af g S Sad S ve A S S S e SY SS SN S N S AS SS S 3 d x S S 3 S S eb 9 rd x S No UCR reference standard exists for either of these treatments D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 23 Evaluation of Weather sensing Landscape Irrigation Controllers LITERATURE CITED Addink S and T W Rodda 2002 Residential landscape study using Aqua ET controllers 5 p report Riverside CA Aqua Conserve Inc Aquacraft 2002 Performance evaluation of WeatherTRAK irrigation controllers in Colorado 23 p report Boulder CO Aquacraft Inc Bamezai A 2001 ET controller savings through the second post retrofit year a brief update 5 p report Santa Monica CA Western Policy Research California Urban Water Conservation Council 2003 Manufacturer product information 45 pp In Proc Options for Weather Based Irrigation Con
4. 6mm 0 25 in occurred in one or more weeks of the month W No UCR reference standard exists and no comparable settings on other controllers in the study D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 18 Evaluation of Weather sensing Landscape Irrigation Controllers Figure 1 Weather sensing irrigation controllers evaluated in 2003 at University of California Riverside Turfgrass and Ornamentals research Facility Riverside CA WeatherSet WS16 Aqua Conserve ET 6 Sunfall Sensor for WeatherSet WeatherTRAK Calsense ET1 with Electronic ET Gauge D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 19 Evaluation of Weather sensing Landscape Irrigation Controllers Figure 2 Irrigation applied by an Aqua Conserve controller compared to ETo and UCR references for 3 landscape treatments in 2003 at University of California Riverside scales vary 25 4 mm 1 in Cool Season Turfgrass 350 300 250 E BHistoric ETo 200 BETO 150 E Aqua 1 5 1 100 0 4 T T T T T T D D 5 S D A 5 OP BO PM AP PP PW S5 Q9 FF ux am KT KF KS SF SF n S yo SU ys SP SOS N AN gt 2 x M Sog v Sox g SO d S S 9
5. Aquacraft 2002 However when SWAT controllers were installed participants were made aware of irrigation system problems i e dysfunctional sprinkler heads and poor system uniformity and asked to remedy them but there was no assessment of the impact of improvements on irrigation system performance or on changes in irrigation requirements Based on the data provided in the report applied water plus rainfall would have been enough for optimal cool season grass ET but there was no plant based evaluation of the controller s performance The results indicate that many of the participants were significantly over irrigating their landscapes prior to installing this product Most of the participants liked the system but were unwilling to pay its on going 49 yr service fee Other widely reported studies of WeatherTRAK s residential landscape performance in Irvine California Hunt et al 2001 and Bamezai 2001 state this product applied water very close to the ET based water budget for the participating households without sacrificing plant performance but objective plant performance evaluations were not employed A 2002 study in Seattle Seattle Public Utilities 2003 found the use of the Aqua Conserve controller with a rain sensor significantly reduced applied water when weather factors were accounted for Participants were mostly satisfied with the product and 85 expressed their landscape s quality was as good as or better than before the product
6. The system was field calibrated so that the GMS would prohibit valve operation until soil moisture content dropped to a point where turfgrass showed signs of stress Comparing actual applied water controlled by the GMS to calculated potential ET using a temperature modified Blaney Criddle method the investigators documented that GMS controlled irrigation was 70 of the modified ET The amount of water applied was roughly equivalent to the minimum water requirement of cool season grass grown in Irvine California as reported by Meyer and Gibeault 1986 and Gibeault et al 1990 which is less than that required for optimum cool season grass performance Studies were conducted during 2001 in Denver and two water districts in Northern California to document residential irrigation applied by Aqua Conserve ET controllers Addink and Rodda 2002 In Denver the water used by 37 participating landscapes 17 equipped with real time temperature sensors was compared to their 5 year historical usage and over 800 non participating residential irrigation users In Northern California Aqua Conserve controllers all equipped with real time temperature sensors were installed at 37 residential sites identified by the water agencies as high volume users Their water usage in 2001 was compared to their 2 or 5 year historic average use Results showed substantial variation with some participants having extremely high water savings some no water sa
7. Treatment Calculations The SWAT devices virtually controlled an existing reference irrigation system and used its system performance data as required in their initial setup This reference system was operated by an independent controller and had a precipitation rate PR of 0 93 in hr 23 6 mm hr and a low quarter distribution uniformity DU of 0 81 The reference irrigation system was used to apply the correct amount of water to a real time turfgrass planting for this study and other landscape research plots at the Turfgrass and Ornamentals Research Facility of the University of California Riverside Standards for programming the reference irrigation system and determining how closely a controller s irrigation schedules met the needs of cool season turfgrass and trees shrubs were established based on previous field research findings while the reference for annual flowers or plantings requiring the soil surface to remain moist was set at 10076 ETo Weekly ETo and rainfall data were collected from CIMIS California Irrigation Management Information System station 44 at U C Riverside located approximately 165 ft 50 m from the irrigated plots Crop coefficient Kc values and plant factors were used with the ETo data to calculate the irrigation requirements of the reference plantings For cool season turfgrass the reference standard treatment UCR 1 was an actual planting of tall fescue located at the research facility irrigated by the reference
8. calculated reference standard amounts and judged equal to the reference amount when applied water was 10 of the reference slightly over under the reference when within 11 to 20 moderately over under the reference when within 21 to 40 of the target and well over under the reference when applied water was gt 40 of the target RESULTS Assessment of Interface and Setup The Aqua Conserve controller was judged to have the friendliest interface and to be the easiest to set up The WeatherSet device followed it closely WeatherSet was easy to use once setup commenced but its interface panel was visually intimidating at first The WeatherTRAK offered an easy and friendly interface but was complex to set up because it required a great deal of technical horticultural information to achieve precision Calsense s 1 with an electronic ET gauge presented the most complex interface and it was equally as complex as WeatherTRAK to D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers set up requiring technical horticultural knowledge and some experience with controller programming Of the four products in this study Aqua Conserve offered the most appropriate interface and setup process for homeowners while WeatherTRAK offered the greatest flexibility in addressing unique site parameters The four irrigation controllers are shown
9. in Figure 1 and their features are reviewed and summarized in Table 1 Weather Parameters Employed and Programming Procedures Required To derive irrigation schedules the Aqua Conserve product used an on site temperature sensor to modulate historic ETo data Calsense used real time ETo estimated from an electronic atmometer ET gauge WeatherSet used an on site solar radiation sensor to adjust historic ETo data and WeatherTRAK used daily real time ETo data from the on site CIMIS station 44 received via a paging signal Table 1 The Aqua Conserve and WeatherSet units require the user to input a location which the controller uses for selecting and adjusting internally stored historical ET data WeatherSet also used data from a rain sensor included with the unit Aqua Conserve ET6 This controller looks sets up and operates much like a standard controller but it uses a combination of historic ETo data and on site real time temperature data to modulate stations runtimes daily from their average July peak schedule that is supplied by the user during initial set up Table 1 Fig 1 The temperature sensor is connected to the controller via an insulated wire and is mounted within 50 feet of the irrigated site on the south or west side of a building in a shaded location such as under an eave or overhang For the study the sensor was mounted adjacent to the irrigated reference turfgrass plot under the west overhang of the irrigation equipment shed in
10. irrigation system to maintain optimum turf quality Gibeault et al 1990 Pittenger et al 2002 Its irrigation was scheduled 3 days each week Tuesday Thursday and Saturday with up to 6 cycles per day by the equation Weekly irrigation amount ETo X Kc R DU where ETo is the previous week s cumulative ETo from CIMIS is the monthly cool season turfgrass Kc Gibeault et al 1990 R is rainfall 20 1 in 2 5 mm DU is the distribution uniformity of the irrigation system The reference standard treatment for the trees shrubs station s irrigation schedule UCR 2 was one irrigation day per week Wednesday with the amount based on findings of Pittenger et al 2002 and Shaw and Pittenger 2004 The irrigation amount was calculated as Weekly irrigation amount weekly ETo x 0 50 D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers The annual flowers or other water stress sensitive planting irrigation reference standard UCR 3 was scheduled 4 days per week Sunday Tuesday Thursday Saturday with the amount calculated as Weekly irrigation amount weekly ETo DU There were no reference standards available for the mixed high and mixed low water use treatments scheduled by WeatherTRAK Treatments 4 and 5 because it was not clear what plant materials these programs represent Irrigation days were elimina
11. which the controller was housed To set up the controller the user enters the current time date and geographic location and then assigns water days and start times to each of the 3 programs From the information input the controller then places the unit along one of 16 historic ETo curves most closely matched to the irrigation site For individual station run times the user must calculate and enter the maximum daily run time that would be applied given each station s PR DU and run days in July the highest ET month The initial average July base schedules for this study were as follows e Cool season turfgrass Program A 135 min wk 3 days wk 3 cycles day 15 min cycle e Trees and shrubs Program B 58 min wk 1 day wk 3 cycles day 19 min cycle e Annual flowers or plants needing about 100 ET Program C 116 min wk 4 days week 3 cycles day 10 min cycle The program runtimes and schedules using the characteristics of the reference irrigation system were calculated as follows Weekly runtime minutes historical avg weekly July ETo x July Kc DU x PR x 60 where e 1 8 in wk 45 mm wk e turfgrass 0 94 Gibeault et al 1990 Kc trees shrubs 0 5 Pittenger et al 2002 and Shaw and Pittenger 2004 and Kc annual flowers or similar planting 1 0 D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigat
12. 03 Water efficient irrigation study final report 19 p report Seattle Public Utilities Resource Conservation Shaw D A and D R Pittenger 2004 in press Performance of landscape ornamentals given irrigation treatments based on reference evapotranspiration In R L Snyder ed Proc IV International Symposium of Horticultural Crops Sept 1 5 2003 Davis CA Acta Hort D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 24 Evaluation of Weather sensing Landscape Irrigation Controllers Snyder L W Pruitt and D A Shaw 1987 Determining daily reference evapotranspiration Oakland University of California Division of Agriculture and Natural Resources Leaflet 21426 Notes D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 25
13. University of California Cooperative Extension Center for Landscape and Urban Horticulture EVALUATION OF WEATHER SENSING LANDSCAPE IRRIGATION CONTROLLERS January through December 2003 A Report Submitted to Office of Water Use Efficiency California Department of Water Resources June 2004 Dennis R Pittenger Area Environmental Horticulture Advisor University of California Cooperative Extension Los Angeles County Dept of Botany amp Plant Sciences University of California Riverside David A Shaw Landscape and Turfgrass Advisor University of California Cooperative Extension San Diego County William E Richie Staff Research Associate University of California Cooperative Extension Dept of Botany amp Plant Sciences University of California Riverside Copyright 2004 Regents of the University of California For copies of this report or additional information concerning the study please contact Dennis Pittenger U C Cooperative Extension Batchelor Hall Extension U C Riverside Riverside 92521 Telephone 951 827 3320 Email dennis pittenger ucr edu The University of California prohibits discrimination or harassment of any person on the basis of race color national origin religion sex gender identity pregnancy including childbirth and medical conditions related to pregnancy or childbirth physical or mental disability medical condition cancer related or genetic characteristics ancestry m
14. access es real time or historical ETo information or other type of environmental data to schedule and adjust landscape irrigation according to the local weather The technologies and user interfaces employed by SWAT devices vary in complexity from traditional controller features and layouts to Internet based management and interface Some rely on remote communication to a data source via a telephone line paging signal or similar technology while others use historical ETo data modified by on site temperature solar radiation or other environmental input sensors Weather sensing controllers are intended to efficiently irrigate landscapes by automatically calculating and implementing irrigation schedules that apply the right amount of water at the right time Centralized irrigation control using a computer on site weather station data and sophisticated valve control has been widely adopted by golf courses and other large irrigated facilities These systems rely on advanced technology and are closely attended to by well trained qualified personnel In contrast the SWAT controllers are intended to be less technical in nature and include residential and small commercial landscapes in their target audience For residential and commercial landscapes the SWAT controllers eliminate hand calculation of ETo based irrigation schedules for each irrigation station and ideally they can take irrigation D R Pittenger D A Shaw and W E Richie 2004 Universi
15. ach controller automatically adjusted irrigation of the three landscape settings in concert with changes in the seasons weather conditions and ETo generally following a characteristic bell shaped curve through the year Figs 2 3 4 The magnitudes of their adjustments were not consistently in proportion to the changes in real time ETo however Frequency of irrigation days wk that controllers watered each treatment is summarized in Table 2 Aqua Conserve The estimated amount of irrigation applied to cool season turfgrass by the Aqua Conserve unit was roughly equal to the amount required by the actual turfgrass reference planting Aqua 1 vs UCR 1 in March April and May but usually well over the reference planting in the other 9 months Fig 2 In the summer months this controller applied irrigation to cool season turfgrass exceeding ETo by 45 to 65 Irrigation applied by Aqua Conserve to trees shrubs was equivalent to or slightly over the reference amount calculated for this treatment Aqua 2 vs UCR 2 in January February March May and September Fig 2 However applied water was well over the UCR 2 reference treatment in April October November and December Fig 2 The amount of water applied to annual flowers or plantings needing about 10096 ETo was typically moderately to well over the reference UCR 3 treatment irrigation amounts and well over ETo in the summer and fall Fig 2 The irrigation frequency determined by Aqua Co
16. aluma CA 94954 Ph 707 769 9696 www hydropoint com D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 17 Evaluation of Weather sensing Landscape Irrigation Controllers Table 2 Number of irrigation days per week scheduled by three weather sensing irrigation controllers for five landscape treatments University of California Riverside Turfgrass and Ornamentals Research Facility Riverside CA 2003 2 Cool Season Turf Trees Shrubs Annual Flowers Y Plants Plants FebX 1 3 0 4 134 0 3 0 1 0 4 0 1 0 1 4 14 23 04 0 1 Marx 0 3 0 4 05 0 3 0 1 0 3 0 1 0 1 0 4 0 5 0 1 0 4 0 1 Apr X 3 46 5 6 1 3 1 24 1 0 1 4 4 6 34 04 0 2 May 3 46 4 7 3 1 2 4 1 2 1 4 4 7 35 4 1 3 Jun 3 46 5 7 3 1 2 4 1 2 1 4 4 7 3 5 4 2 3 1 2 Jul 3 3 5 6 7 3 1 2 4 1 2 1 4 4 6 45 4 2 3 2 Aug 3 46 3 7 3 1 34 2 1 4 57 56 4 3 2 Sep 3 34 2 3 3 1 2 3 1 2 1 4 45 3 5 4 2 3 12 Oct 3 13 13 3 1 1 2 1 1 4 2 4 24 4 1 2 1 2 Nov X 1 3 1 2 1 2 0 3 0 1 0 1 1 0 1 4 2 3 2 0 4 1 1 Dec 1 3 1 2 1 2 0 3 0 1 0 1 1 0 1 4 1 2 12 04 1 1 2 Aqua Conserve WS WeatherSet WT WeatherTRAK UCR U C Riverside reference standard Y UCR base schedules cool season turf 3 days wk trees shrubs 1 day wk annual flowers 100 ETo 4 days wk X Rainfall gt
17. anufacturers Although there were several other SWAT irrigation control devices available or arriving in the market at the time the study was initiated the four products selected represented a range of technologies and approaches in use California Urban Water Conservation Council 2003 The products and models included in the study were Aqua Conserve ET 6 Aquaconserve Riverside CA WeatherSet WS16 The WeatherSet Co Winnetka CA WeatherTRAK Hydropoint Data Systems Inc Petaluma CA Calsense 1 with electronic ET gauges California Sensor Corp Carlsbad CA At the outset the programming procedures followed with each controller and the weather parameter s they employed were documented Also the ease of interface and setup for each product was judged as easy friendly interface simple to understand and set up with little or no technical horticultural knowledge or experience with irrigation controllers or complex unfriendly interface complicated to set up with input parameters requiring technical horticultural knowledge and experience with landscape irrigation control and management Irrigation Treatments Controllers did not irrigate real landscape settings Instead stations on each controller were set up and programmed according to the manufacturer s directions to schedule irrigation automatically from January through December 2003 for the following hypothetical landscape plantings e Cool season turfgrass
18. arital status age sexual orientation citizenship or status as a covered veteran covered veterans are special disabled veterans recently separated veterans Vietnam era veterans or any other veterans who served on active duty during a war or in a campaign or expedition for which a campaign badge has been authorized in any of its programs or activities University policy is intended to be consistent with the provisions of applicable State and Federal laws Inquiries regarding the University s nondiscrimination policies may be directed to the Affirmative Action Staff Personnel Services Director University of California Agriculture and Natural Resources 300 Lakeside Drive 6 Floor Oakland CA 94612 3550 510 987 0096 Evaluation of Weather sensing Landscape Irrigation Controllers Table of Contents EXECUTIVE SUMMAR Y ETEO Fal Med pad jh i ce RIP wig e BACKGROUND AND OBJECTIVES deu ke tea METHODS AND PROCEDURES EF d QU E P up Selection and Initial Assessment of SWAT Controllers eese Irrigation Treatments sess nba pipe ke bres dteli rvu EP RN Ure ERE NIS ERAS PEE a VH Reference Irrigation System and Treatment D ta C US p RESULTS T
19. chedules Unfortunately no product was able to produce highly accurate irrigation schedules consistently for every landscape setting when compared to research based reference comparison treatments The findings suggest that weather sensing irrigation controller manufacturers need to reassess their algorithms and formulae used by the controllers in order for them to provide more precise irrigation schedules Further study is needed to determine if the shortcomings of the units evaluated are related to self contained ETo data assumed values proprietary adjustment factors used the weather sensing method employed or the weather sensing instrument used by the unit Regrettably problems with the ET gauge prohibited us from fully evaluating the Calsense controller Furthermore the findings indicate that adoption of SWAT will not eliminate human interaction in landscape irrigation management Some products require users to calculate a base schedule in the setup process while others require detailed technical knowledge in horticulture and irrigation management to set them up Each controller evaluated would have required significant manual adjustment of its schedules to irrigate the landscape treatments accurately The inability to provide accurate irrigation schedules without significant tweaking indicates that weather sensing or SWAT controllers will usually require professional monitoring and follow up adjustment to their input parameters a
20. e set to apply ETo based schedules the calculations and programming involved are laborious and too complicated for many people to implement An alternative method is to install an irrigation controller that automatically adjusts watering schedules based on local weather data or other environmental parameter correlated with ETo and plant water demand In 2003 we conducted a science based evaluation of selected weather sensing irrigation controllers at the University of California Riverside Turfgrass and Ornamentals Research Facility The study was designed to determine the climatic data the controllers use how easy they are to setup and operate and how closely their irrigation regimes match landscape irrigation needs established by previous field research This report provides the results of the study and our conclusions BACKGROUND AND OBJECTIVES There are at least 12 irrigation control products that automatically schedule irrigation based on local weather or other environmental parameters California Urban Water Conservation Council 2003 These devices are commonly termed weather sensing or weather based irrigation controllers and the technology is collectively referred to by the irrigation industry as Smart Water Application Technology or SWAT The devices replace a traditional controller or work in coordination with a traditional controller and have proprietary hardware and or software that automatically receive s or
21. er D A Shaw W E Richie 2004 University of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers EXECUTIVE SUMMARY Irrigation controllers that set and adjust water application in response to changes in the weather are now available for residential and commercial use These devices are commonly termed weather sensing ET or weather based irrigation controllers and the technology is collectively referred to by the irrigation industry as Smart Water Application Technology or SWAT Many of the dozen or so devices now available automate the use of reference evapotranspiration ETo data or other environmental parameters correlated with evapotranspiration ET and plant water demand Ideally SWAT products take irrigation management out of peoples hands by automatically scheduling landscape irrigation Their use theoretically can simplify and improve landscape irrigation scheduling minimize runoff and result in measurable water conservation Although there have been several studies on the performance of various SWAT devices few of them provide scientific and objective analysis of a product s or technology s performance None of the studies referenced water used or water saved objectively to plant performance so it is difficult to judge if the amount of water applied was over under or equal to the plants real time needs for acceptable landscape performance optimum growth
22. er inputs Optional user inputs Real time ETo from on site electronic atmometer historical ETo backup soil moisture sensor is optional Water days program assignment program start times precip rate for ea station type of sensor input password maximum number of stations Historical ETo adjusted with on site solar radiation Sunfall sensor rainfall sensed with MiniClik sensor Maximum daily runtime for each valve type of plant material start time current time and day no water days None type of sprinkler can be input only on newer models Local real time ETo and rainfall data sent to controller via satellite daily can add any on off rain sensor ET zone zip code max ET for zone level of automation desired sta start times no water day type of sprinkler emitter plant type Soil texture amount of sun shade precipitation rate distribution uniformity Ease of Interface Both easy Easy interface Complex Scheduling parameters that are automatically adjusted Run time and water days Accumulation feature prevents short run times in cool weather Twice mo based on How often are base programs adjusted historical ETo with daily adjustment from temperature sensor Number of available programs Run time cycle repeats At each irrigation event 5 general and 2 drip programs Run time then water days 3 pre set programs flowers lawn grou
23. esults in shallow water penetration and in combination with deficit irrigation it often results in poor landscape performance The performance of the Weather Set unit indicates that with cool season turfgrass there would have been brown or dead grass through most of the growing season For trees shrubs extreme soil water deficits would have likely occurred during portions of the year Many trees and shrubs might tolerate the wintertime water deficits produced by station WeatherSet 2 especially deciduous plants but it is unlikely that many commonly grown species would perform acceptably with the extreme soil water deficits created in the summer It is estimated that annual flowers and plantings needing 100 ETo would have been significantly under watered in the summer but well watered in the other seasons WeatherTRAK Irrigation water applied to cool season grass by the WeatherTRAK unit was equal to the UCR 1 reference treatment in April and October but was slightly over or under the reference amounts during January February May August September and December Fig 4 It moderately over irrigated compared to UCR 1 in March June and July and irrigated well over in November There was no seasonal pattern to the deviation from the reference irrigation D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 12 Evaluation of Weather sensing Landscape Irrigation Controllers amount WeatherTRAK usua
24. ht over water them in fall It is likely that connecting a rain sensor to this product would greatly improve its irrigation scheduling both frequency and amount for turfgrass and annual flowers in rainy months such as February and March of 2003 Weather Set The estimated amount of water applied to cool season turfgrass by the WeatherSet controller was equal to the actual turfgrass reference planting WeatherSet 1 vs UCR 1 in the winter January November and December but it was moderately to well under the reference for the remainder of the year Fig 3 Similarly the trees shrubs station typically applied only 20 to 30 of ETo in most months which was well under the calculated reference amount Fig 3 The amount of water applied to annual flowers or plantings needing about 100 ETo was relatively close to the reference in most months Fig 3 but it was moderately under the reference in the summer and part of the fall June July August and October and well under it in the dry winter month of January The frequency of irrigation determined by the WeatherSet unit was erratic for all the irrigation treatments Table 2 In general irrigations were scheduled more frequently in the summer months which were probably adequate for the cool season turf and annual flowers about 100 ETo treatments However for the trees shrubs treatment the increased frequency resulted in very short runtimes during the summer months This practice usually r
25. ion Controllers e DU 0 81 the distribution uniformity of the irrigation system which was used only in the turfgrass schedule calculations e PR 0 93 in hr 2 55 min mm the precipitation rate of the irrigation system e 60 the factor required to convert units to minutes Using the equation and values above produced the average July base Weekly Runtime Minutes Cool season grass 1 8 in x 0 94 0 81 x 0 93 in hr x 60 135 min Trees shrubs 1 8 in x 0 5 0 93 in hr x 60 58 min Annual flowers similar planting 1 8 in x 1 0 0 93 in hr x 60 116 min The total minutes were then divided by the weekly number of run days and cycles per day Final program run times for the three landscape scenarios were 15 minutes for turfgrass 19 minutes for trees shrubs and 10 minutes for annual flowers for each run time within a cycle and day Although the Aqua Conserve controller display continues to show the initial run times the actual run times are automatically adjusted usually downward from the initial average July runtime setting according to the historical ETo curve and the temperature sensor input There is an Accumulation feature option that eliminates extremely short watering runtimes in cool weather With the Accumulation feature on the controller will skip days until at least 5096 of the water time has accumulated and then water on the next scheduled day With the Accumulation feature off the controller will water
26. iversity of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers unit for the various treatments inputs appear in parentheses and any parameters not listed were set to default values Cool season grass Treatment 1 Set Station to Program 1 Set Program Mode fully automated Set Sprinkler type mixed rotors Set Plant Type cool season grass Set Soil Type sandy loam Set Microclimate sun all day Set Slope Factor none to slight 096 slope In mid August the following parameters were entered to obtain a custom schedule PR 0 93 in hr and DU 0 81 Tree Shrub program Treatment 2 Set Station to Program 2 Set Program Mode fully automated Set Sprinkler type mixed rotors Set Plant Type trees Set Soil Type sandy loam Set Microclimate sun all day Set Slope Factor none to slight 0 slope Annual flowers or similar planting Treatment 3 Set Station to Program 3 Set Program Mode fully automated Set Sprinkler type mixed rotors Set Plant Type flowers Set Soil Type sandy loam Set Microclimate sun all day Set Slope Factor none to slight 096 slope Mixed High Water Use Plants Treatment 4 set up Feb 2003 Set Station to Program 4 Set Program Mode fully automated Set Sprinkler type custom PR 0 93 in hr and DU 0 81 Set Plant Type mixed high water use plants Set Soil Type sandy loam Set Microclimate sun all da
27. ler algorithms use inaccurate values for plant water need factors crop coefficients and other parameters then implementation of a weather sensing controller will not result in conservation and landscape water use might increase in some situations Similarly the study results show that acceptable landscape plant performance is not assured when using a weather sensing controller Thus weather sensing controllers are not a panacea for landscape water conservation but they can be an effective irrigation management tool Based on the technology currently available each controller product needs to evaluated for its strengths and weaknesses and then matched to situations where its strengths can be exploited D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 15 Evaluation of Weather sensing Landscape Irrigation Controllers Table 1 Features of weather sensing irrigation controllers evaluated at the University of California Riverside Turfgrass and Ornamentals Research Facility Riverside CA 2003 Aqua Conserve ET6 up WeatherSet WS16 WeatherTRAK Historical ETo modulated daily with real time on site temperature sensor no automated rainfall adjustment rain sensor can be added Weather input s used to automatically adjust irrigation Water days program assignment program start times maximum run time for each station in July user lockout settings Required initial us
28. lly adjusted irrigation very appropriately in response to rainfall except in November The input of specific values for DU and PR in mid August to the cool season turfgrass treatment WeatherTRAK 1 appeared to improve WeatherTRAK s scheduling precision as seen in the reduced deviation from the reference treatment thereafter In contrast the estimated amounts of water applied to the trees shrubs treatments were consistently well over the UCR 2 reference levels in every month of 2003 Fig 4 WeatherTRAK grossly over irrigated the trees shrubs treatment in the summer and fall months applying 2 to 3 times the UCR 2 amount The applied water was at least 2596 greater than ETo in February June July August October November and December The annual flowers treatment was also moderately or well over irrigated the in all months except January March April and June Fig 4 Only in March were irrigation applications less than UCR 3 which may have been an appropriate response to rainfall during that month However the controller did not respond in this manner to rainfall in February In all other months WeatherTRAK 3 typically applied amounts of water well over real time ETo In the mixed high water use plants setting WeatherTRAK 4 the amount of irrigation applied from April through August by WeatherTRAK was typically near ETo but it was well under ETo in April and moderately over ETo in September and December Fig 5 Irrigation applied to
29. mixed low water use plants WeatherTRAK 5 from May through December was 4096 to 5096 of ETo except in May when it was 1596 of ETo and in July when it was 6096 of ETo Fig 5 Since no reference standards were available for these treatments the accuracy and appropriateness of these schedules are unknown The irrigation frequencies determined by the WeatherTRAK unit in the summer were 1 to 2 days wk and 3 to 6 days wk for the trees shrubs and the annual flower treatments respectively Table 2 Irrigation was less frequent in the other seasons The cool season turfgrass setting however was irrigated much more frequently than the UCR 1 reference in the spring and summer The irrigation frequencies for trees shrubs and annual flowers were horticulturally sound Conversely the near daily spring and summer irrigation frequencies for turfgrass were considered unsound because they often result in shallow water penetration and if water amounts are sufficient may increase disease and weed problems WeatherTRAK s performance indicates that cool season grass would have been irrigated very effectively 4 of the year but significantly over irrigated for the remainder Unfortunately the unit tended to over irrigate in the summer months when ET was highest Adding custom PR and DU values in the set up parameters improves the precision of the controller s irrigation scheduling Nevertheless commonly used trees and shrubs would be significantly over irrigated t
30. nd or manual modification of their schedules for a considerable period after the initial setup in order to realize the optimum irrigation program for each station Users should first look to reduce runtimes and or frequency because schedules tend to exceed plants needs according to our findings Evaluation of plant response expectations of the landscape s appearance and other factors will need to guide the necessary adjustments It is important to note that many SWAT manufacturers including those represented in this study continue to adjust and or re design the algorithms and features of their products to improve their capabilities Perhaps the most important factor affecting weather based irrigation controller performance is the quality and accuracy of the information supplied when setting it up For example Aqua Conserve s relatively easy to setup and ability to deliver accurate schedules is heavily reliant on the user knowing and entering a July base schedule that is accurate for the plants irrigated while WeatherTRAK s relatively complex setup information requires the user to have a relatively good technical understanding of the site and the plants irrigated However greater complexity and technicality of required setup information does not necessarily result in more accurate water conserving irrigation schedules as was demonstrated in the trees shrubs schedule calculated by WeatherTRAK complex and technical setup versus that of Aqua Co
31. ndcover shrub water days are selected automatically newer model offers Low Water Use plant setting Run time water days cycle repeats Each station s program and schedule are calculated by the controller from a series of user supplied inputs for plant type slope microclimate etc Start times per Automatically adjusts cycles for slopes from user input Programs interruptible with automatic restart Max run n input by user must consider slope No of valves that can operate on one station 2 stations plus 1 pump User HS p for cycling on ps in initial set Up to 8 valves station can simultaneously run station from regular and drip programs Yes if maximum daily runtime 220 min newer models feature multiple cycle soak options No of stations 12 D Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 16 Evaluation of Weather sensing Landscape Irrigation Controllers Aqua Conserve ET6 PEE WeatherSet WS16 WeatherTRAK External Radio modem linkable Microwave signal from Nonvolatile 9v battery retains time and dafe Nonvolatile Nonvolatile Nonvolatile Yes Yes Yes Yes Runtime clock may be 20 to 30 sec delay until valve actually opens or shuts Internal crop coefficients English or Spanish 7 14 21 or 28 day schedules laptop interface flow monitoring and lateral break protecti
32. nserve simple non technical setup D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 14 Evaluation of Weather sensing Landscape Irrigation Controllers Each product studied demonstrated significant strengths and weaknesses summarized below Aqua Conserve was the simplest easiest to operate and most appropriate for homeowner use of those products studied When the user supplied base setup schedule is accurate as it was in the study it applied water at the correct frequency but tended to apply more water than needed to all landscape treatments It irrigated trees shrubs with reasonably good precision however Possibly Aqua Conserve employs a factor for non uniformity of irrigation systems in its algorithm s that results in over irrigation if uniformity is already factored into a station s base setup schedule as was notable in this study with cool season turfgrass and annul flower treatments Calsense ETI with an electronic ET gauge input offered the most complex interface and it was equally as complex to set up Since the electrical connections and function of the electronic ET gauge repeatedly failed in our study it was impossible to evaluate fairly its weather based irrigation scheduling capabilities WeatherSet was simple and easy to use but visually intimidating It produced very inaccurate irrigation schedules that would have damaged plants due to severe under irrigation These result
33. nserve was consistently on par with the UCR reference for all landscape irrigation treatments Table 2 It automatically eliminated water days in some weeks during the winter when ETo was very low so that runtimes did not become excessively short when the Accumulation feature was used Because it lacked the optional rain sensor Aqua Conserve sometimes scheduled irrigation in weeks when rainfall met D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 11 Evaluation of Weather sensing Landscape Irrigation Controllers plants water needs Adding a rain sensor would enable the Aqua Conserve to apply water at a highly accurate and effective interval in all seasons Overall Aqua Conserve delivered water at the correct frequency Table 2 but tended to apply more water than needed to all landscape treatments Fig 2 Perhaps a follow up global adjustment in station runtimes using the Percentage Reduction feature would have enabled the unit to more accurately schedule irrigations Aqua Conserve was most accurate in scheduling water to trees and shrubs where it closely met the water needs for acceptable performance of commonly grown trees shrubs about of the year However it typically applied more water than necessary for optimum cool season turfgrass performance For plantings needing about 100 ETo it would ensure that these plant materials are well watered in the spring and summer but it mig
34. o such a degree that excess growth and or reduced root health would be expected Newly planted annual flowers or a new lawn would be well irrigated in the winter and spring but probably over irrigated in the summer and fall Use of the mixed high water use plants default setting would be expected to provide irrigation approximating 100 ETo while the mixed low water use plants default setting would usually provide irrigation of 40 to 50 of ETo However the irrigation schedules for these two settings deviated significantly from these values during a few months D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 13 Evaluation of Weather sensing Landscape Irrigation Controllers SUMMARY AND CONCLUSIONS The results of this study provide useful information and a science based perspective about the performance and potential benefits of weather based irrigation control technology Each controller studied adjusted its irrigation schedules through the year roughly in concert with weather and ETo changes so that irrigation was automatically and substantially reduced in fall winter spring versus summer However the magnitudes of their adjustments were not consistently in proportion to the changes in real time ETo It was also clear that incorporation of a rain sensor or other accurate means of accounting for local rainfall is essential for a weather sensing controller to calculate correct irrigation s
35. on usage summary backlit 8 row display manual adjustment of ETo for each station accurate Misc features Prices as of 2003 see mfr for details and current pricing Manufacturer contact information may be 20 to 30 sec delay until valve actually opens or shuts Rain switch lock out feature to prevent unauthorized modification of program replacement panels which fit most common controllers usage log for current day and previous week s run times water reduction feature allows reduction of run times up to 20 159 for 6 stn to 875 for 32 stn with locking steel cabinet Aquaconserve 2900 Adams St Ste A25 Riverside CA 92504 Ph 909 352 3891 www aquaconserve com Up to 4500 California Sensor Corp 2075 Corte del Nogal Ste P Carlsbad CA 92003 Ph 800 572 8608 www calsense com may be 20 to 30 sec delay until valve actually opens or shuts Rain switch master valve manual operation of selected stations or 2 minute test 500 600 16 stn 200 300 8812 stn price includes Sunfall sensor and MiniClik rain sensor WeatherSet Company 807 Corbin Ave Winnetka CA 91306 Ph 818 993 1449 www weatherset com may be 20 to 30 sec delay until valve actually opens or shuts Rain switch master valve manual adjustment possible from 50 to 25 for each station 175 plus 48 per year signal fee HydroPoint Data Systems 1726 Corporate Circle Pet
36. on the program days The controller also offers a Water Reduction feature that globally reduces the watering times for all programs by an entered percentage To see a log of total run time for the past 7 days one pushes and holds the previous button with the dial on The display toggles through the run time for each of the six stations When the Next button is held down the display toggles through the current day s run time for each station Directions for parameters that can be viewed when the dial is on are displayed on the front panel of the controller and are easy to understand Calsense ETI with electronic ET gauge input Initial setup of the Calsense 1 includes entering time date etc much like a standard controller It uses the ET gauge to obtain on site real time ETo data that is then used with optional programmed Kc values and user supplied data about the irrigation system to adjust irrigation amounts for each station Table 1 Figure 1 The ET gauge is connected to the controller and mounted on a nearby post which has turfgrass fetch around it but in a location which gets minimum sprinkler precipitation irrigation water tends to seal up the felt and ceramic surface of the atmometer When used with an atmometer the controller is set up with real time ET from ET gauge The ET gauge was powered with AA batteries in this study although it can be powered directly by the controller power suppl
37. or stations based on set up information supplied by the user For the study the Sunfall sensor was sited adjacent to the irrigated turfgrass reference plots on the eve of the roof of the irrigation equipment shed where the controller was located The sensor was not shaded at any time To set up the WeatherSet controller the user sets the current date and time as well as a daily irrigation start time and a desired no water day for each valve Similar to the Aqua Conserve unit the user must calculate and set the maximum daily runtime required in the hottest weather for each valve station For the study the maximum daily runtime for each station was 19 min day based on the average July schedule in the cool season turfgrass research plots used for reference in the study This daily runtime is equivalent to the maximum weekly runtime entered in the Aqua Conserve unit which was the average weekly July time divided by 7 135 min wk 7 d wk 19 min Next the predominant plant material in the zone irrigated by each valve is selected as lawn groundcover shrubs or flowers With this information the controller sets the irrigation days and runtimes automatically from algorithms that use the real time solar radiation to calculate a Sunfall factor which adjusts historical ETo The WeatherSet groundcover shrubs program was used for the trees shrubs treatment in the study WeatherTRAK The WeatherTRAK controller has the most distincti
38. or other plant based criteria In 2003 we conducted a science based evaluation of selected weather sensing irrigation controllers to determine the climatic data the controllers use how easy they are to setup and operate and how closely their irrigation regimes match landscape irrigation needs established by previous field research The products and models included in the study were Aqua Conserve ET 6 Aquaconserve Riverside CA WeatherSet WS16 The WeatherSet Co Winnetka CA WeatherTRAK Hydropoint Data Systems Inc Petaluma CA and Calsense ET1 with an electronic ET gauge California Sensor Corp Carlsbad CA The programming procedures followed with each controller the weather parameter s they employed and the ease of interface and setup for each product were documented and appraised Stations on each controller were set up and programmed according to the manufacturer s directions to schedule irrigation automatically from January through December 2003 for the following hypothetical landscape plantings e Cool season turfgrass tall fescue at optimum quality Treatment 1 e Trees shrubs Treatment 2 e Annual flowers or about 100 ETo Treatment 3 Two additional stations were set up on the Weather TRAK product during the winter and summer of 2003 respectively using the unit s following pre set programs e Mixed high water use plants Treatment 4 e Mixed low water use plants Treatment 5 The SWAT devices virtuall
39. provided relatively accurate irrigation schedules for cool season grass but grossly over watered the trees shrubs treatment Other important findings and conclusions from the controllers studied are e greater complexity and technicality of required setup information does not necessarily result in more accurate water conserving irrigation schedules e adoption of SWAT will not eliminate human interaction in landscape irrigation management e weather sensing controllers will likely require professional monitoring and follow up adjustment of their initial irrigation schedules e use of weather sensing controllers does not assure landscape water conservation or acceptable landscape plant performance D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers INTRODUCTION Advances in irrigation control technology provide numerous tools to landscape managers homeowners and water agencies for conserving water in urban landscapes Irrigation controllers that set and adjust water application in response to changes in the weather are now available for residential and commercial use Many of these devices utilize reference evapotranspiration ETo data to calculate landscape water budgets and determine irrigation schedules Historical and real time ETo data are widely available in California and while any automatic irrigation controller can b
40. r D A Shaw and W E Richie 2004 University of California Cooperative Extension 21 Evaluation of Weather sensing Landscape Irrigation Controllers Figure 4 Irrigation applied by a WeatherTRAK controller compared to ETo and UCR references for 3 landscape treatments in 2003 at University of California Riverside scales vary 25 4 mm 1 in Cool Season Turfgrass 250 200 150 Historic BETo E WeatherTRAK 1 5 100 1 c 50 4 04 r r r r r r r r r r li OI rx JP SU SS PS a na e Q a Q5 d qw oW PK OH SF LK 9 SU O8 9 uS KF KL qo S g N S a X SO SU QS SQ L R wee eo E P Trees Shrubs 300 TET ElHistoric ETo z BETO 8 Bl WeatherTRAK 2 5 2 z Annual Flowers 300 250 3 200 DHistoric ETo amp 150 BETo a BI WeatherTRAK 3 5 OUCR3 1 z 50 4 0 A BD QU A QAO A A DM SU aS av 9 AS wo SY qq E SU x vr S 9 K amp S FFF FPS HFK D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 22 Evaluation of Weather sensing Landscape Irrigation Controllers Figure 5 Irrigation applied by a WeatherTRAK controller at mixed high and mixed low water use plants settings compared to ETo
41. s suggest that the product had not been effectively field tested prior to the study However WeatherSet incorporates a theoretically and scientifically sound approach for modulating historical ETo using a measure of solar radiation which is the principal driver of plant water use Refinement of the algorithms or the solar energy units employed might result in improved reliability and accuracy of irrigation schedules Hopefully the newer models released by WeatherSet will overcome these deficiencies WeatherTRAK was the most sophisticated controller studied and required the most technical knowledge on the part of the user It is very flexible in addressing the specific parameters found in each landscape setting but it requires a professional landscape manager or equivalently trained individual to setup the unit accurately In this study WeatherTRAK provided relatively accurate irrigation schedules for cool season grass but tended to over irrigate other plantings grossly over watering trees shrubs treatments The results of this study demonstrate that use of a weather sensing controller does not assure landscape water conservation Conservation can occur only if previous water use was known to be excessive and the schedules produced by the weather sensing controller match the water needs of turfgrass and landscape plant materials If previous water use was on target for the plant material s needs if deficit irrigation was practiced or if the control
42. ss management professionals and homeowners are interested in adopting weather sensing irrigation controllers but because of the limitations of previous studies and reports they are unsure about the effectiveness of these devices in conserving water while meeting landscape irrigation needs The objectives of this study were to evaluate selected weather sensing irrigation controllers and 1 Discern the type of climatic or weather data the devices use to calculate irrigation schedules automatically D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers 2 Assess the complexity of their setup and use 3 Determine their effectiveness in automatically scheduling irrigation regimes that match ETo based landscape water needs established by field research 4 Identify and evaluate their potential as water conservation tools METHODS AND PROCEDURES Selection and Initial Assessment of SWAT Controllers In the spring and summer of 2002 four commercially available controller products representing unique proprietary approaches and technologies for providing automated weather sensing irrigation control in residential and commercial landscapes were selected for study at the Turfgrass and Ornamentals Research Facility at the University of California Riverside Selections were based on discussions with water agency personnel and controller m
43. tall fescue at optimum quality Treatment 1 e Trees shrubs Treatment 2 e Annual flowers or other planting requiring the upper few inches of soil to remain moist or about 100 ETo Treatment 3 Two additional stations were set up on the Weather TRAK product during the winter and summer of 2003 respectively using the unit s following pre set programs e Mixed high water use plants Treatment 4 e Mixed low water use plants Treatment 5 D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers Only the minimum information required for a controller to schedule irrigation automatically for the landscape settings was provided in the initial setup No additional information was entered and no manual adjustments were enacted to modify controllers programs or station runtimes so an evaluation could be made of each unit s built in knowledge and ability to apply automatically the correct amount of irrigation Controllers were not manually shut off during rain events For the WeatherTRAK product which can utilize additional site and system parameter data to calculate custom schedules the details for system performance data soil texture and root depth were input for the cool season grass station in mid August to determine if greater irrigation precision resulted by entering this information Reference Irrigation System and
44. ted in the reference standards fall through spring when ETo was low or rainfall was significant Data Collection The weekly amount of irrigation actually applied to the reference turfgrass planting was recorded as were the weekly amounts of irrigation virtually applied to the other reference treatment plantings While the controllers evaluated did not irrigate actual landscape plantings their station run times were recorded in tenths of minutes by electro mechanical time counters IVO model B148 001 Genesis Automation Powell OH wired to receive the electrical signal generated when a controller powered the circuit to open an irrigation valve The weekly cumulative run times were recorded for all stations by the counters and the days irrigation occurred were noted Run time minutes were converted to depth millimeters of applied water based on the precipitation rate of the reference irrigation system that the controllers were virtually operating The weekly cumulative runtimes corresponding depths of applied water and ETo values were summarized into monthly totals in order to provide a meaningful analysis of controller performance The virtual amounts applied by the controllers studied were then compared to the amounts actually applied to the cool season grass reference plot and the amounts calculated to have been applied to the trees shrubs and annual flower reference plantings Monthly amounts of water applied by a controller were compared to the
45. trol for Residential and Small Commercial Sites Workshop Claremont CA March 20 2003 Sacramento Calif Urban Water Conservation Council Estrada 2003 Preliminary data for pilot ET controller program 1 p Jn Proc Options for Weather Based Irrigation Control for Residential and Small Commercial Sites Workshop Claremont CA March 20 2003 Sacramento Calif Urban Water Conservation Council Gibeault V A S T Cockerham J M Henry and J Meyer 1990 California turfgrass It s use water requirement and irrigation Calif Turfgrass Culture 39 3 4 1 9 Hunt T D Lessick J Berg J Wiedman T Ash D Pagano M Marian and A Bamezai 2001 Residential weather based irrigation scheduling evidence from the Irvine ET controller study 52 p report Irvine CA Irvine Ranch Water District report Meyer J L and V A Gibeault 1986 Turfgrass performance under reduced irrigation Calif Agric 40 7 8 19 20 Pittenger D R W E Richie and D R Hodel 2002 Performance and quality of landscape tree species under two irrigation regimes In R L Green et al eds Turfgrass and Landscape Irrigation Studies Final Report Section I Riverside University of California Cooperative Extension reprint Qualls R J J M Scott and W B DeOreo 2001 Soil moisture sensors for urban landscape irrigation effectiveness and reliability J Am Water Resources Assoc Vol 37 3 547 559 Seattle Public Utilities 20
46. ty of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers management out of peoples hands by automatically scheduling landscape irrigation Their proprietary algorithms purportedly tailor the amount and timing of water applied to meet the specific real time needs of the plants and in some cases address the constraints of a site such as cycling irrigation of slopes to reduce runoff In theory the use of these devices in residential and commercial landscapes will simplify and improve landscape irrigation scheduling minimize runoff and result in measurable water conservation SWAT products vary in price from about 100 to over 3 000 depending on the number of stations controlled and other variables and some require a set up fee or an on going service fee in the range of 25 yr to 250 yr California Urban Water Conservation Council 2003 Services of a professional landscape manager may be required to perform the initial setup of the controller and irrigation stations depending on the complexity and technical knowledge required by a device There have been several studies regarding the reliability and water conservation achieved with SWAT study was conducted in Boulder CO with granular matrix sensors GMS or Watermark placed in the soil to interrupt pre set irrigation schedules of standard irrigation control valves whenever soil moisture was adequate for turfgrass needs Qualls et al 2001
47. ules through the year roughly in concert with weather and ETo changes but the magnitudes of their adjustments were not consistently in proportion to the changes in real time ETo Unfortunately no product was able to produce highly accurate irrigation schedules consistently for every landscape setting when compared to research based reference comparison treatments Aqua Conserve was the simplest easiest to operate and most appropriate for homeowner use of those products studied It applied water at the correct frequency and irrigated trees shrubs with reasonably good precision but it tended to apply more water than needed to all landscape treatments especially in the summer for cool season turfgrass Calsense ETI with an electronic ET gauge input offered the most complex interface and it was equally as complex to set up Since the electrical connections and function of the electronic ET gauge repeatedly failed in our study it was impossible to evaluate fairly its weather based irrigation scheduling capabilities WeatherSet was simple and easy to use but visually intimidating It produced very inaccurate irrigation schedules that would have damaged plants due to severe under irrigation WeatherTRAK was the most sophisticated controller studied and the most flexible in addressing the specific parameters found in each landscape setting but it requires a professional landscape manager or equivalently trained individual to setup the unit accurately It
48. ve appearance and user interface Figurel but it requires the most user input both in volume and technical degree of the four controllers evaluated Table 1 Programming it for maximum precision in scheduling irrigation requires accurate knowledge of the landscape s soil texture microclimate slope plant type plant rooting depth and irrigation system The controller has built in information and algorithms that enable it to use local real time ETo received daily via wireless paging signal technology with user supplied site details to adjust irrigation schedules for each station in relation to weather conditions Setup begins with the user setting a start time that is used for all stations The current time date and zip code are also set The manufacturer automatically assigns an ET Zone maximum zone ET and a water district code The user scrolls via 2 dials through a list of selections and yes no questions to set up each station Fortunately it comes with a detailed user s manual that walks the operator through the setup and programming For the study setup was accomplished by enabling the Advanced Features Each controller station was programmed for fully automated operation by following the setup steps for landscape scenarios of cool season grass trees shrubs annual flowers or other planting needing about 10096 ETo The following procedure was used to program the WeatherTRAK D R Pittenger D A Shaw and W E Richie 2004 Un
49. vings and a few with increased water usage Overall the investigators concluded that residential landscape irrigation was reduced 7 to 2596 by using this product and water districts will realize a significant reduction in total water demand although limited data was presented to support this Similarly preliminary results from an on going pilot program at 29 sites in Los Angeles both residential and commercial involving two SWAT controller products WeatherTRAK and Water2Save was showing irrigation savings as follows 14 are saving 2 to 10 38 are saving 10 to 3096 2496 are saving 33 to 79 and 2496 are increasing water use 896 to 71 Estrada 2003 The findings are for the latter half of 2002 and early 2003 representing a period where plants water demand decreases dramatically from mid summer into winter a period when irrigation managers often neglect to re program controllers accordingly However the basis for establishing water savings in this project was not provided D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers A single season study in Colorado among 10 participants interested in conserving landscape water showed the WeatherTRAK product irrigated landscapes at about 81 of ETo which reduced landscape irrigation about 2096 from the amount sites historically used after accounting for real time variance
50. was installed A small number of these prior studies provide any scientific and objective analysis of a product s or technology s performance Most were observational studies or demonstrations in which a controller manufacturer conducted the study or their representative was integrally involved in conducting the study Projects were typically designed so that it was difficult or impossible to know how much change in water use was the result of the controller s performance versus the weather or other factors The studies usually compared historical water use with water use after a weather based controller product was installed without normalizing results to account for differences between real time and historical weather conditions or without accurately determining how efficiently the landscapes were irrigated prior to utilizing the new controller Few studies referenced applied water to ETo None of the studies referenced water applied or water saved objectively to plant performance so it is difficult to judge if the amount of water applied was over under or equal to the plants real time needs for acceptable landscape performance optimum growth or other plant based criteria Since studies did not objectively and scientifically evaluate how plant material performed in response to the amount of water applied by the weather sensing controller they lack an objective basis for measuring changes in water use Urban water agencies landscape and turfgra
51. y Programs are defined with water days and start times first and then stations are assigned to programs as desired Start times can be assigned to each program so they do not overlap Setup requires a precipitation rate for each station so it can calculate time and depth of water application After completing setup a percentage of ET can be manually entered for each station to account for uniformity losses or other parameters and factors unique to the station D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers Unfortunately in the Calsense system the electrical connections and function of the electronic ET gauge repeatedly failed making it impossible to keep it operating properly This product was eliminated from the study in March and none of its performance data is presented WeatherSet This controller has a unique user interface unlike a traditional controller It utilizes an array of dials toggles dipswitches and LED lights for user input and information feedback Fig 1 Data from a solar radiation sensor connected to the unit is used to adjust irrigation The weekly irrigation schedule for each station 15 increased or decreased based on the cumulative solar radiation measured termed Sunfall Table 1 Proprietary algorithms calculate the Sunfall factor and use it with historical ETo to calculate irrigation schedules f
52. y Set Slope Factor none to slight 0 slope Set Root Depth 12 in D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension 10 Evaluation of Weather sensing Landscape Irrigation Controllers Mixed Low Water Use Plants Treatment 5 set up June 2003 e Set Station to Program 5 e Set Program Mode fully automated e Set Sprinkler type custom PR 0 93 in hr and DU 0 81 e Set Plant Type mixed high water use plants e Set Soil Type sandy loam e Set Microclimate sun all day e Set Slope Factor none to slight 0 slope e Set Root Depth 18 in Evaluation of Irrigation Schedules Real time reference ET ETo for 2003 was near historic ETo Snyder et al 1987 in most months but it was significantly less in July implying that plant water use would have been somewhat less than average during that month Figs 2 3 4 Rainfall was only slightly less than normal for the 12 month period with significant rainfall in February and March Figs 2 3 4 Thus the climate in 2003 was representative and provided a sound basis for testing the automated capabilities of the weather sensing irrigation controllers Actual applied irrigations to the cool season turfgrass reference plots UCR 1 provided the amount of water necessary for optimal turfgrass performance The correct amount of water for trees shrubs UCR 2 and annual flowers UCR 3 treatments were estimated mathematically E
53. y controlled an existing reference irrigation system and used its system performance data as required in their initial setup Simultaneously the reference irrigation system was used to apply the correct amount of water to a real time tall fescue turfgrass planting whose water needs served as the reference standard treatment comparison for the cool season turfgrass treatment Reference standard treatments for trees shrubs and annual D R Pittenger D A Shaw and W E Richie 2004 University of California Cooperative Extension Evaluation of Weather sensing Landscape Irrigation Controllers flowers treatments were calculated using on site real time ETo data and plant factors developed primarily from previous research The weekly amount of irrigation actually applied to the reference turfgrass planting was recorded as were the weekly amounts of calculated irrigation required by the other reference treatment plantings The station runtimes of the controllers evaluated were recorded and converted to depth of applied water using the performance characteristics of the reference irrigation system the controllers virtually operated The weekly cumulative depths of water applied by controllers were summarized into monthly totals and compared to the real time cool season grass reference applications and the calculated reference standard amounts for the other treatments The results of this study show each controller evaluated adjusted its irrigation sched
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