Stacia L. Davis

Irrigation of Residential Landscapes Using the Toro Intelli-Sense Controller in Southwest Florida

AbstractThe objective of the research reported in this paper was to determine the potential water-savings effectiveness of Toro Intelli-Sense evapotranspiration (ET)-based irrigation controllers in single-family homes. Of the 36 cooperators selected, 21 cooperators were outfitted with Toro Intelli-Sense TIS-612 (the ET group) and the remaining 15 were used as comparisons. The ET group reduced irrigation compared to the gross irrigation requirement by 23–41% and the 9-year historical average by 23–34%. Results varied based on the relationship between historical irrigation and the gross irrigation requirement, with water savings of 24%, no difference, and an increase of 54% when the historical value exceeded, approximated, and was less than the gross irrigation requirement, respectively. Turfgrass quality was maintained above an acceptable threshold for both treatments. In southwest Florida, a properly programmed Intelli-Sense controller is recommended when irrigation exceeds the gross irrigation requiremen...

LANDSCAPE IRRIGATION WITH EVAPOTRANSPIRATION CONTROLLERS IN A HUMID CLIMATE

The objective of this article is to present summary findings of multiple research studies concerning evapotran- spiration (ET) controllers. Each study provided unique information concerning the performance and implementation tech- niques necessary to ensure successful integration with irrigation systems to optimize scheduling for water conservation. Based on these studies, ET controllers have the potential for irrigation savings of as much as 63%, without sacrificing landscape quality, when implemented in moderate to high water use scenarios and programmed correctly. Only homes that irrigated more than 450 mm per year had irrigation savings with an ET controller in southwest Florida. The ET con- trollers that underwent Irrigation Association Smart Water Application Technologies (SWAT) testing experienced oscilla- tions in irrigation adequacy and scheduling efficiency dependent on rainfall. Assuming acceptable levels for irrigation adequacy and scheduling efficiency of 80% and 95%, respectively, there were only a few periods during the Florida SWAT test when both scores were above these thresholds. A maximum of 10% of scores were passing in any of the three evalua- tion periods with frequent rainfall, indicating that properly accounting for rainfall is a challenge for many of these con- trollers. The SWAT scores are indicators of water savings only if there is a potential for savings due to excess irrigation prior to implementation of the ET controller.

Evaluation and Demonstration of Evapotranspiration-Based Irrigation Controllers

Irrigation systems need to become more efficient to minimize the use of limited water resources while maintaining landscapes of acceptable quality to consumers. This manuscript gives a preliminary report on the evaluation of three commercially available evapotranspiration (ET) based controllers in residential landscaped plots with respect to irrigation application and landscape quality compared to a homeowner irrigation schedule. The irrigation treatments were as follows: T1, Weathermatic Smart Line Series controller; T2, Toro Intelli-sense; T3, ETwater Smart Controller 100; T4, a time-based treatment; and T5, 60% of T4. This paper reports preliminary results from May 25, 2006 to November 30, 2006. T1 overestimated ETo by 32%, but applied less water than all other treatments during the summer season. Water savings occurred even though ETo was overestimated due to an underestimation of the crop coefficient for warm season turfgrass [0.85 in Allen et al. (1998)] programmed into the controller (0.60) and due to frequent irrigation event bypass during the rainy summer season. The Weathermatic controller applied 11% and 14% less water than the theoretical gross irrigation requirement during the summer and fall seasons, respectively. The Toro Intelli-sense controller applied 126 mm in the fall, which was 40% less than theoretical requirements, and had the most accurate ETo of all the controllers. The ETwater controller overestimated ETo by 7% and applied 63% more irrigation water than was required theoretically. During this preliminary testing, the ET controllers did not result in turf quality below acceptable levels.

Smart Water Application Technology (SWAT™) Evaluation in Florida

Water used for turfgrass/landscape irrigation represents a significant portion of the total water used in Florida. This area of water use is increasing with population growth, which is projected to rise from 17 million to 20 million by 2015. If current water use trends continue, many areas will experience severe water shortages. Smart Water Application Technology (SWAT™) consists of irrigation controllers that establish or modify irrigation scheduling based on soil/weather variables. This paper summarizes the research carried out in Florida, regarding the use of ET controllers, soil moisture sensor controllers and rain sensors on turfgrass/landscape irrigation; and evaluates their effectiveness for irrigation water conservation. Testing locations range from plot scale on turfgrass and landscape material to cooperating home sites. Results have shown that controllers can cut irrigation as much as 90% during rainy periods and 41% during dry periods while maintaining turfgrass quality. Preliminary results in the residential arena show that soil moisture sensors and rain sensors could also save a significant amount of irrigation water when implemented (up to 50%). None of the SWAT™ controllers tested have shown a reduction in turfgrass/landscape quality when correctly set/implemented.

Implementing Smart Controllers on Single-Family Homes with Excessive Irrigation

AbstractIn this study, smart irrigation controllers were targeted toward single-family potable water customers in Orange County, Florida with excessive landscape irrigation patterns. Out of five treatments, four treatments received either an evapotranspiration controller (ET) or soil moisture sensor (SMS) controller, installed by a contractor, but two technology treatments included an educational program (+Pgm) component. The fifth treatment was a comparison treatment (MO) with no interventions to their normal irrigation scheduling methods. After 22 months of evaluation, both +Pgm treatments reduced irrigation application, ranging from 21 to 52%. However, none of the treatments performed with high efficiency in all seasons. Only a few treatments were able to maintain irrigation totals within a gross irrigation requirement (GIR) range from 60 to 100% efficiency. The technology treatments that participated in the customized educational program were more likely to achieve additional reductions in irrigation ...

Importance of ET Controller Program Settings on Water Conservation Potential

In unincorporated Orange County, Florida, 57% to 62% of single-family residential homes were found to regularly over-irrigate, resulting in the need to find better ways to schedule automatic irrigation. The objective of this research was to evaluate the effects of programming for identical virtual landscapes to further explore the water savings potential of evapotranspiration (ET) controllers. As a virtual test, three Rain Bird ET controllers were studied: the ESP-SMT controller with two firmware options (original and an updated), and the ESP-SMTe, a replacement product for the ESP-SMT. Irrigation was scheduled for a virtual central Florida landscape by altering possible program settings of plant type, microclimate, soil type, and density that relate directly to parameters used in the soil water balance. The ESP-SMTe consistently applied similar amounts of irrigation to the ESP-SMT with updated firmware, indicating that controller updates were minor between the two models. The settings were optimized for Florida landscapes by selecting a heavier soil type, increasing the shade, and selecting a medium stand for a custom plant type, resulting in reductions in irrigation application. The ESP-SMTe and ESP-SMT with updated firmware were different from the ESP-SMT with original firmware, where newer models applied more water despite identical settings, averaging 12 to 21 mm more per month than the original firmware. Additionally, all of the controllers were unable to fully account for rainfall throughout the test resulting in a minimum of 51% in over-irrigation compared to the gross irrigation requirement (GIR). Increasing the accuracy of rainfall accounting would be extremely beneficial to overall water conservation and efficiency. In a separate, independent ET controller study, there was a large discrepancy in irrigation application among multiple brands programmed to irrigate the same virtual landscape. This further shows the importance of understanding the algorithms behind the program settings.

Importance of ET controller program settings on water conservation potential

Abstract. In unincorporated Orange County, FL, 57% to 62% of single-family residential homes were found to regularly over-irrigate resulting in the need for finding better ways to schedule automatic irrigation. The objective of this research was to evaluate the effects of programming for identical landscapes to further explore the water savings potential of evapotranspiration (ET) controllers. As a virtual test, three Rain Bird ET controllers were implemented: the ESP-SMT controller with two firmware options (original and an updated), and the ESP-SMTe, a replacement product for the ESP-SMT. Irrigation was scheduled for a virtual central Florida landscape by altering possible program settings of plant type, microclimate, soil type, and density that relate directly to parameters used in the soil water balance. The ESP-SMTe consistently applied similar amounts of irrigation to the ESP-SMT with updated firmware, indicating that controller updates were minor between the two models. The settings were optimized by selecting a heavier soil type, increasing the shade, and selecting a medium stand for a custom plant type, resulting in significant reductions in irrigation application. The ESP-SMTe and ESP-SMT with updated firmware were significantly different from the ESP-SMT with original firmware, where the newer models had higher irrigation despite identical settings, averaging 12 mm to 21 mm more per month than the original firmware. Additionally, all of the controllers were unable to fully account for rainfall throughout the test resulting in a minimum of 51% in over-irrigation compared to the gross irrigation requirement (GIR). Increasing the accuracy of rainfall accounting would be extremely beneficial to overall water conservation and efficiency.