EVALUATION OF ACCURACY AND LONGEVITY OF EXPANDING-DISK RAIN SENSORS By LEAH MEEKS A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ENGINEERING UNIVERSITY OF FLORIDA 2010 1 © 2010 Leah Meeks 2 To my grandmothers, Geraldine Rosalee Meeks and Clara Lena Davis 3 ACKNOWLEDGMENTS I thank my mother, Sharon Lea Meeks, for her unconditional love and encouragement, my fiancé and best friend, James Anthony Hernandez, for his support, and my aunt, the late Dr. Lynn Langer Meeks, for her inspiration. I would like to thank the members of my graduate committee, Dr. Kati White Migliaccio and Dr. Thomas Obreza, for their assistance on my research. A big thank you goes to my advisor Dr. Michael D. Dukes for his guidance and the chance to experience a new side of irrigation. I would also like thank Stacia Davis, Bernard Cardenas- Lailhacar, and Mary Shedd McCready for their help on this research project. 4 TABLE OF CONTENTS page ACKNOWLEDGMENTS.............................................................................................................. 4 LIST OF TABLES ......................................................................................................................... 7 LIST OF FIGURES....................................................................................................................... 9 LIST OF ABBREVIATIONS ...................................................................................................... 14 ABSTRACT ................................................................................................................................. 15 CHAPTER 1 INTRODUCTION................................................................................................................. 17 2 EXPANDING-DISK RAIN SENSOR ACCURACY ......................................................... 31 Introduction .......................................................................................................................... 31 Materials and Methods ....................................................................................................... 34 Treatments .................................................................................................................... 34 Monitoring ..................................................................................................................... 35 Statistical Analysis ....................................................................................................... 36 Results and Discussion ...................................................................................................... 36 Climactic Conditions .................................................................................................... 36 Number of Times in Open Switch Mode .................................................................. 37 Accuracy of Rain Sensors .......................................................................................... 40 Change in Accuracy of Rain Sensors over Time .................................................... 40 Summary and Conclusions................................................................................................ 41 3 EXPANDING-DISK RAIN SENSOR DRY-OUT AND POTENTIAL IRRIGATION SAVINGS.............................................................................................................................. 59 Introduction .......................................................................................................................... 59 Materials and Methods ....................................................................................................... 61 Treatments .................................................................................................................... 61 Monitoring ..................................................................................................................... 62 Statistical Analysis ....................................................................................................... 64 Results and Discussion ...................................................................................................... 64 Climactic Conditions .................................................................................................... 64 Time in Open Switch Mode (Dry-Out) ...................................................................... 65 Dry-out Tracking........................................................................................................... 67 Potential Irrigation Savings......................................................................................... 68 Summary and Conclusions................................................................................................ 69 5 4 RELATIONSHIP BETWEEN EXPANDING-DISK RAIN SENSOR DISK LENGTH AND PERFORMANCE ..................................................................................... 83 Introduction .......................................................................................................................... 83 Materials and Methods ....................................................................................................... 84 Treatments .................................................................................................................... 85 Monitoring ..................................................................................................................... 85 Statistical Analysis ....................................................................................................... 86 Results and Discussion ...................................................................................................... 86 Length by Installation date and setting..................................................................... 86 Disk Length and Traveling Distance ......................................................................... 87 Effect on Interruption Performance ........................................................................... 88 Summary and Conclusions................................................................................................ 88 5 CONCLUSIONS AND FUTURE WORK.......................................................................... 96 Conclusions.......................................................................................................................... 96 Future Work ......................................................................................................................... 99 LIST OF REFERENCES .........................................................................................................1 00 BIOGRAPHICAL SKETCH .....................................................................................................1 05 6 LIST OF TABLES Table page 2-1 Rain sensor treatment description............................................................................... 43 2-2 Summary of functionality problems for treatments and replicates. ........................ 43 2-3 Average depth of rainfall before rain sensors switched to Open Switch Mode.... 44 2-4 Summary of changes in accuracy for change in rainfall required for Open Switch Mode.................................................................................................................... 44 3-1 Treatment description. ................................................................................................... 71 3-2 Monthly irrigation depth to replace historical evapotranspiration values based on Dukes and Haman (2002a). Run times are based on an irrigation application rate of 38 mm/hr assuming system efficiency of 60% and considering effective rainfall. The Reduced UF IFAS irrigation schedule is 60% of the UF IFAS irrigation schedule. .................................................................... 71 3-4 Total potential water savings per treatment for all treatments compared with a 2 d/wk and a 1 d/wk irrigation schedule for the study period (Oct/Nov 2006 to 1 Dec 2009). ............................................................................................................... 72 3-5 Variation in total potential water savings per replicate for the WL and MC treatments compared with UF IFAS 2 d/wk irrigation recommendations. ............. 72 3-6 Variation in total potential water savings per replicate for the Hunter, Irritrol, and Toro treatments compared with UF IFAS 2 d/wk irrigation recommendations........................................................................................................... 73 3-7 Variation in total potential water savings per replicate for the WL and MC treatments compared with UF IFAS 1 d/ wk irrigation recommendations. ............ 73 3-8 Variation in total potential water savings per replicate for the Hunter, Irritrol, and Toro treatments compared with UF IFAS 1 d/ wk irrigation recommendations........................................................................................................... 73 4-1 Description of rain sensors details for each treatment. ............................................ 90 4-2 Average disk length for each treatment at two intervals: initial and final (276 days of installation). ....................................................................................................... 90 4-3 Average disk length for the treatments installed 13 February 2009 at three intervals: initial, 81 days of installation, and final (276 days of installation).......... 91 7 4-4 Disk length for replicates of treatments installed 25 March 2005 at three intervals: initial (February), 81 days of installation (May), and final (November, 276 days of installation). ......................................................................... 91 4-5 Disk length for replicates of treatments installed 13 February 2009 at three intervals: initial (February), 81 days of installation (May), and final (November, 276 days of installation). ......................................................................... 91 4-6 Comparison of average length change and travel distance from closed-switch mode to open-switch mode of treatments installed in 13 February 2009. The February travel distance was measured on a rain sensor before installation. ..... 92 4-7 Comparison of average length change of each treatment from 13 February 2009 to 16 November 2009 and the travel distance each treatment from closed-switch mode to open-switch mode. Travel distance was measured at the end of the study. ...................................................................................................... 92 8 LIST OF FIGURES Figure page 2-1 WL (model Wireless Rain-Clik, Hunter Industries, Inc., San Marcos, CA) rain sensor. A) Expanding disks inside ventilation window, B) quick-response expanding disks, C) Ventilation window adjustment knob, D) antenna................. 45 2-2 MC (model Mini-Clik®, Hunter Industries, Inc., San Marcos, CA) rain sensor. A) Rainfall threshold setting slots, B) expanding disks, C) dry-out adjustment ring and vents. ................................................................................................................ 45 2-3 Irritrol (model RFS 1000, Irritrol Systems, Inc., Riverside, CA.) rain sensor. A) Rainfall threshold setting slots, B) dry-out adjustment ring, C) antenna. .............. 46 2-4 Toro (model TWRS, Toro Company, Inc., Riverside, CA) rain sensor. A) Rainfall threshold setting slots, B) dry-out vent, C) antenna. .................................. 46 2-5 Detail of expanding disk material and threshold adjustment of Mini-Clik (Hunter Industries, Inc.) rain sensor. A) Rainfall threshold setting slots, B) hygroscopic expanding disk material. ......................................................................... 47 2-6 Research site located at the University of Florida Agricultural and Biological Engineering facilities. Shown: weather station on left, WL, 3MC, 3MC, and 13MC treatments installed on left board, and Hunter, Irritrol, and Toro on right board. ...................................................................................................................... 47 2-7 Installed Hunter Wireless Rain-Clik, three on left and one on right, and Mini- Clik rain sensors with four wireless receivers for WL and data logger. ................. 48 2-8 Installed Hunter, Irritrol, and Toro rain sensors, left to right, with wireless receivers (Irritrol on left and Toro on right), and data logger................................... 48 2-9 Relationship between manual rain gauge and weather station tipping bucket rain gauge with the calibration factor applied to the tipping bucket data with more than 15 mm of rainfall. ......................................................................................... 49 2-10 Relationship of rain events greater than 15mm between manual rain gauge and weather station tipping bucket rain gauge with the calibration factor applied to the tipping bucket data. ............................................................................... 49 2-11 Relationship of rain events less than 15 mm between manual rain gauge and weather station tipping bucket rain gauge without the calibration factor applied to the tipping bucket data. ............................................................................... 50 2-12 Comparison of monthly and cumulative rainfall during the study period for WL and MC treatments and average historical rainfall for north central Florida. ........ 50 9 2-13 Comparison of monthly and cumulative rainfall during the study period for Hunter, Irritrol, and Toro treatments and average historical rainfall for north central Florida. ................................................................................................................ 51 2-14 Cumulative and daily rainfall during the WL and MC treatments study period with the rainfall setting and the respective theoretical number of times each should have gone into OSM. ........................................................................................ 52 2-15 Cumulative and daily rainfall during the Hunter, Irritrol, and Toro treatments study period with the rainfall setting and the respective theoretical number of times each should have gone into OSM..................................................................... 53 2-16 Cumulative number of times into OSM for WL and MC treatments. Data from 28 January to 9 June 2008 are not included due to all WL replicates not functioning. Erratic replicates within treatments are not included after their respective improper functioning dates (WL-B 21 September 2007 and 13MC- C 8 July 2008). Numbers with different letters indicate a statistical difference using Tukey-Kramer adjusted p-values of p<0.05. ................................................... 54 2-17 Cumulative number of times the WL replicates went into OSM. WL stopped functioning on 21 September 2007. ............................................................................ 54 2-18 Cumulative number of times the 3MC replicates went into OSM. The Theoretical value is the number of times the replicates should have gone into OSM based on rainfall. .................................................................................................. 55 2-19 Cumulative number of times the 6MC replicates went into OSM. The Theoretical value is the number of times the replicates should have gone into OSM based on rainfall. .................................................................................................. 55 2-20 Cumulative number of times the 13MC replicates went into OSM. The Theoretical value is the number of times the replicates should have gone into OSM based on rainfall. .................................................................................................. 56 2-21 Cumulative number of times into OSM for Hunter, Irritrol, and Toro treatments. The Theoretical value is the number of times the replicates should have gone into OSM based on rainfall. Numbers with different letters indicate a statistical difference using Tukey-Kramer adjusted p-values of p<0.05. ............................................................................................................................. 56 2-22 Cumulative number of times Hunter into OSM. The Theoretical value is the number of times the replicates should have gone into OSM based on rainfall. ... 57 2-23 Cumulative number of times Irritrol went into OSM. The Theoretical value is the number of times the replicates should have gone into OSM based on rainfall............................................................................................................................... 57 10