1. Smart Irrigation Controllers:
Water Conservation Potential
Michael D. Dukes, Ph.D., P.E.
Agricultural & Biological Engineering
Institute of Food and Agricultural Sciences (IFAS)
Utah Green Industry Conference
Salt Lake City, UT, Jan 26, 2010

2. Irrigation is a Standard “Appliance”

3. Irrigation is a Standard “Appliance”

4. SMS TESTING ON
BERMUDAGRASS PLOTS

5. 12' × 12'

6. SMS Testing Bermudagrass, Gainesville
• 1 d/wk four brands SMS
• 2 d/wk four brands SMS 3 SMS frequencies
• 7 d/wk four brands SMS
• Time 2 d/wk with rain sensor
• 60% of time 2 d/wk with rain sensor
• Time 2 d/wk without rain sensor Comparisons
• Non-irrigated

7. IFAS Recommended Irrigation Run Times
Weekly Monthly
Irrigation Irrigation
(inches) (inches)
Jan 0.04 0.16
Feb 0.00 0.00
Mar 0.09 0.34
Apr 0.49 1.98
May 0.84 3.34
Jun 0.75 3.00
Jul 0.70 2.79
Aug 0.64 2.57
Sep 0.82 3.28
Oct 0.54 2.15
Nov 0.34 1.34
Dec 0.13 0.52
Total 21.5

8. IFAS Irrigation Recommendations - Tables

9. SMS Testing Bermudagrass, Gainesville
• 1 d/wk four brands SMS
• 2 d/wk four brands SMS
• 7 d/wk four brands SMS
• Time 2 d/wk with rain sensor (100% IFAS)
• 60% of time 2 d/wk with rain sensor (60%
IFAS)
• Time 2 d/wk without rain sensor
• Non-irrigated

10. Acclima Rain Bird
Irrometer Water Watcher

11. 1
SMS Controllers
in Experiment
1: Sensor
Controllers
2:Timer
2

12. Expanding
Disk Rain
Sensor

13. TQ RATINGS (1 to 9 scale)
3 4
5 7

14. Water Savings 2004+05,
Normal Rainfall Frequency
Treatment TOTAL Savings compared to
(in) 2-WOS (%)
2-WOS 59.6 0
SMS Based
Avg 16.5 72
1-d/w 16.5 b 72
2-d/w 18.8 a 68
7-d/w 14.3 c 76
WOS = without sensor Avg = average
SMS = soil moisture sensor

15. Turfgrass Quality

16. Water savings 2006
Dry Conditions
Treatment TOTAL Savings compared to
(in) 2-WOS (%)
2-WOS 25.9 0
SMS Based
Avg 11.9 54
1-d/w 14.9 a 43
2-d/w 11.7 b 55
7-d/w 9.2 c 64
WOS = without sensor Avg = average
SMS = soil moisture sensor

17. Conclusions
• Rain sensor ¼”  34% savings normal rainfall
frequency; 13% savings dry weather

18. Conclusions
• Rain sensor ¼”  34% savings normal rainfall
frequency; 13% savings dry weather
• SMS savings: 72% rainy weather; 54% dry weather,
>2 times more than an RS

19. Conclusions
• Rain sensor ¼”  34% savings normal rainfall
frequency; 13% savings dry weather
• SMS savings: 72% rainy weather; 54% dry weather,
>2 times more than an RS
• SMS controllers can minimize irrigation and
maintain turf quality in dry weather

20. SMS/ET Controllers 2006-08, Drought
Conditions
St. Augustinegrass
testing ongoing since
March 2006
72 plots
18 treatments & 4 replicates
A: Rain Sensors
B: Soil Moisture Sensor & ET
Controllers Photo May 2006, M.L. Shedd

21. Irrigation Savings Compared to a Time
Schedule No Rain Sensor
80
72
70
59
60
Irrigation Savings (%)
54
50
39
40 Gainesville
Citra
30
20
10
0
Normal rainfall Dry conditions

22. Soil Moisture Sensors
X
X
Water
Watcher
Rain Bird
Irrometer
Acclima

23. Base Line
LawnLogic

24. SMS & RS TESTING ON
COOPERATING HOMES,
PINELLAS CO.

25. Experimental Design
• 59 residential cooperating
homes
 4 locations
• 4 treatments

26. Treatments
• SMS, Current irrigation system without rain sensor
and with a soil moisture sensor controller
• EDU+RS, Current irrigation system with rain
sensor & seasonal run time guidelines
• RS, Current irrigation system with rain sensor
• WOS, Current irrigation system without a
sensor

27. Pinellas County Homes, Irrigation
Nov 06 – Dec 08
70 0
62 a 2
60
54 a 4
Monthly Effective Precipitation (inches)
Irrigation Application (inches)
50 6
8
40
34 a 10
30
12
22 b 14
20
16
10
18
0 20
Nov-06 Feb-07 May-07 Sep-07 Dec-07 Mar-08 Jul-08 Oct-08 Jan-09
Effective Rainfall SMS EDU+RS RS WOS

28. Pinellas County Homes, Irrigation
Nov 06 – Dec 08
70 0
62 a 2
60
54 a 4
Monthly Effective Precipitation (inches)
Irrigation Application (inches)
50 6
8
40
34 a 10
30
12
22 b 14
20 65%
16
10
18
0 20
Nov-06 Feb-07 May-07 Sep-07 Dec-07 Mar-08 Jul-08 Oct-08 Jan-09
Effective Rainfall SMS EDU+RS RS WOS

29. Irrigation Frequency
(# Irrig. Events per Month)
Treatment Mean Std. Dev. Max Min
(#/month) (#/month) (#/month) (#/month)
SMS 2.1 b 2.8 11 0
EDU+RS 3.6 ab 4.1 20 0
RS 4.7 a 5.6 22 0
WOS 5.2 a 6.5 29 0

30. Meter Only Home (not in compliance) Meter Only Home (in compliance)
1.2 0.0 1.2 0.0
1.0 1.0 1.0 1.0
Irrigation Application (inches/day)
Irrigation Application (inches/day)
Precipitation (inches/day)
Precipitation (inches/day)
0.8 2.0 0.8 2.0
0.6 3.0 0.6 3.0
0.4 4.0 0.4 4.0
0.2 5.0 0.2 5.0
0.0 6.0
0.0 6.0
May-08 Jun-08 Jul-08 Aug-08 Sep-08
May-08 Jun-08 Jul-08 Aug-08 Sep-08
Rain Sensor Home Soil Moisture Sensor Home
1.2 0.0 1.2 0.0
1.0 1.0 1.0 1.0
Irrigation Application (inches/day)
Irrigation Application (inches/day)
Precipitation (inches/day)
Precipitation (inches/day)
0.8 2.0 0.8 2.0
0.6 3.0 0.6 3.0
0.4 4.0 0.4 4.0
0.2 5.0 0.2 5.0
0.0 6.0 0.0 6.0
May-08 Jun-08 Jul-08 Aug-08 Sep-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08

31. 200 0 200 0
180 180
160 50 160 50
Monthly Precipitation (mm)
Monthly Precipitation (mm)
Irrigation Application (mm)
Irrigation Application (mm)
140
SMS 140 RS
120
100 Homes
100 120
100
Homes 100
80 150 80 150
60 60
40 200 40 200
20 20
0 250 0 250
Effective Rainfall Avg. Irr. Applied (SMS) Calculated Irr. Need Effective Rainfall Avg. Irr. Applied (RS) Calculated Irr. Need
200 0 200 0
180 180
160 50 160 50
Monthly Precipitation (mm)
Monthly Precipitation (mm)
Irrigation Application (mm)
Irrigation Application (mm)
140
120
Meter 100
140
120
RS + 100
100 Only 100 Edu.
80
Homes 150 80 Homes 150
60 60
40 200 40 200
20 20
0 250 0 250
Effective Rainfall Avg. Irr. Applied (MO) Calculated Irr. Need Effective Rainfall Avg. Irr. Applied (EDU) Calculated Irr. Need

32. ET CONTROLLER TESTING,
HILLSBOROUGH CO.

33. ET Controller Study
GCREC Hillsborough County
• Three ET controllers: T1, T2, T3
 Weathermatic, Smartline SL800
 Toro, Intellisense TIS-612OD
 ETwater, Smart Controller 100
• T4: Timeclock with RS
• T5: 60% of T4

34. GCREC Plot plan

35. GCREC Rainfall
25 2006-2007 100
Historical Mean 90
91.2
Cumulative 2006-2007
Cumulative Rainfall (in)
20 80
Monthly Rainfall (in)
Cumulative Historical
70
16.0 71.2
15 60
50
10 8.8 40
8.3 8.3 8.8 8.4
8.0 7.5 8.4 7.5
6.6
30
6.5 6.0
4.9 5.1
5 3.7 4.0
20
3.0 3.1 2.9 2.9 3.2 3.0
2.5 2.4 2.7
1.8 2.1 2.2 10
1.4 1.1 0.8 0.6 0.0
0 0
May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
Month (2006-2007)

36. ET Controller Conclusions Summary
• Water Savings Compared to Time (no RS)
• ET controllers
• 43% average annual
• 60% winter
• Rain sensor (RS), 21%
• Reduced time w/ RS treatment, 53%
• No relationship between water application and
turfgrass quality. More potential savings?

37. But will ET controllers work in the real
world?!
Residential study in Hillsborough County…
• 38 residential cooperators in Hillsborough Co.
o 21 homes have an ET controller
o 17 homes are a comparison group
• All volunteers are moderate to high water users

38. ET Controller Initial Data, SW Fla.
Two Sites
10
Cumulative Average Irrigation Applied
9 Comparison
ET Controllers
8
Historical Comparison
7 Historical ET Controllers
6 ~50%
5
(in)
4
3
2
1
0
9/26 10/10 10/24 11/7 11/21 12/5 12/19 1/2 1/16
Date (2008-2009)

39. Smart Irrigation Controller Irrigation
Reduction Potential
Method Location Irrigation Weather Funding
Savings agency
Time clock
Homes in Central
adjustment w/ 30% Normal to rainy SJRWMD
Fla.
rain sensor
Rain sensor Plots in Gainesville 34% Normal to rainy SWFWMD
15% Dry
Soil moisture
Plots in Gainesville 70-90% Normal to rainy SWFWMD
sensor control
Plots in
Up to 40% Dry
Gainesville/Citra
Homes in Pinellas Co. 65% Dry (1 d/wk) SWFWMD
Plots in Hillsborough Hillsborough
ET controllers Up to 60% ~Normal
Co. Co./FDACS
Up to 40% Dry
Homes in ~50%
Dry (ET, variance)
Hillsborough Co. (initially)

40. The Answer is NOT Only Smart Controllers
• Smart Controllers have water conservation
potential but….

41. The Answer is NOT Only Smart Controllers
• Smart Controllers have water conservation
potential but….
• Target “high” water users
• Must be implemented with hands on
training of contractors
• Ongoing certification/verification program
should be implemented

42. Irrigation Savings Potential
80
Rainy
70
Dry
Irrigation Savings (%)
60
50
40
30
20
No data
No data
No data
10
0
Time Clock Rain Sensor Soil Soil ET ET
Adjustment Moisture Moisture Controller, Controller,
Sensor, Sensor, plots homes
plots homes

43. So, What’s the Silver Bullet in
Smart Irrigation Control?

44. BLANK SLIDE

45. Soil Moisture Sensors
• Advantages
 Inexpensive, for smaller sites with “lumped”
hydrozones
 Simple programming of SMS controller
 Integrates on site rainfall
• Disadvantages
 Burying wires
 Not all sensors are accurate under variety of
conditions
 Programming time clock runtimes correctly

46. ET Controllers
• Advantages
 No wires to bury
 Programming matches irrigation theory
 Two way communication in some cases
• Disadvantages
 Steep programming learning curve (depends on
device)
 Costly for “simple” sites
 Ongoing fees for some
 Replaces the existing and functional timer

47. PAYBACK EXAMPLE

48. Payback Period, Irrigation Meter
Assumes 50% irrigation efficiency; JEA 2009 costs; total annual irrigation of 43”; 50% savings
$4,000
3.0 ac
$3,500
2.5 ac
$3,000
2.0 ac
$2,500
Irrigation Savings
$2,000
1.5 ac
$1,500
$500 1.0 ac
installed
$1,000 cost, one
SMS 0.5 ac
controller
$500
0.25 ac
$0
1 2 3 4 5 6 7 8 9 10 11 12
Month

49. Irrigation applied, Irrigation Meter
Assumes 50% irrigation efficiency; JEA 2009 costs; total annual irrigation of 43”
4,000
3.0 ac
3,500
3,000 2.5 ac
Landscape Irrigation (kgal)
2,500
2.0 ac
2,000
1.5 ac
1,500
1.0 ac
1,000
0.5 ac
500
0.25 ac
0
1 2 3 4 5 6 7 8 9 10 11 12
Month

50. Payback Period, Potable+Sewer
Assumes 50% irrigation efficiency; JEA 2009 costs; total annual irrigation of 43”; 50% savings
$12,000
3.0 ac
$10,000
2.5 ac
$8,000 2.0 ac
Irrigation Savings
$6,000 1.5 ac
$4,000 1.0 ac
$500
installed 0.5 ac
$2,000 cost, one
SMS 0.25 ac
controller
$0
1 2 3 4 5 6 7 8 9 10 11 12
Month

51. See Videos & Narrated Power Point
• http://irrigation.ifas.ufl.edu
• Video
 Irrigation controllers
 Rain sensors
 Soil moisture controllers
 Weather based (ET) controllers
 Smart Water App. Tech. (virtual turf field day)
• Narrated ppts
 ET controllers
 Irrigation scheduling
 Irrigation components
 Irrigation myth busters
 Soil moisture sensor controllers

52. Thank you!
Southwest Florida Water Management District, Pinellas Co.
Utilities, St. Johns River Water Management District, Florida
Department of Agriculture and Consumer Services,
Hillsborough Co. Water Dept., Florida Nursery Growers and
Landscape Assoc., Florida Turfgrass Assoc., Florida Sod
Growers Co-op.
mddukes@ufl.edu
http://irrigation.ifas.ufl.edu