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

Smart Irrigation Controllers:

Water Conservation Potential

Irrigation is a Standard “Appliance”

Irrigation is a Standard “Appliance”

SMS TESTING ON

BERMUDAGRASS PLOTS

12' × 12'

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

• 60% of time 2 d/wk with rain sensor

• Time 2 d/wk without rain sensor

• Non-irrigated

Comparisons

3 SMS frequencies

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

IFAS Irrigation Recommendations - Tables

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

Acclima

Water WatcherIrrometer

Rain Bird

1

2

1: Sensor Controllers

2:Timer

SMS Controllers in Experiment

Expanding Disk Rain Sensor

4

5 7

3

TQ RATINGS (1 to 9 scale)

Water Savings 2004+05,

Normal Rainfall Frequency

Treatment 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

TOTAL

Turfgrass Quality

Water savings 2006

Dry Conditions

Treatment 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

TOTAL

• Rain sensor ¼” 34% savings normal rainfall

frequency; 13% savings dry weather

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

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

Conclusions

SMS/ET Controllers 2006-08, Drought

ConditionsSt. Augustinegrass

testing ongoing since

March 2006

72 plots

18 treatments & 4 replicates

A: Rain Sensors

B: Soil Moisture Sensor & ET

ControllersPhoto May 2006, M.L. Shedd

Irrigation Savings Compared to a Time Schedule No Rain Sensor

72

54

59

39

0

10

20

30

40

50

60

70

80

Normal rainfall Dry conditions

Irri

gati

on S

avin

gs

(%)

Gainesville

Citra

Acclima

Water Watcher

IrrometerRain Bird

Soil Moisture Sensors

XX

Base Line

LawnLogic

SMS & RS TESTING ON

COOPERATING HOMES,

PINELLAS CO.

Experimental Design

• 59 residential cooperating homes 4 locations

• 4 treatments

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

0

2

4

6

8

10

12

14

16

18

200

10

20

30

40

50

60

70

Nov-06 Feb-07 May-07 Sep-07 Dec-07 Mar-08 Jul-08 Oct-08 Jan-09

Mo

nth

ly E

ffe

ctiv

e P

reci

pit

atio

n (i

nch

es)

Irri

gati

on

Ap

plic

atio

n (i

nch

es)

Effective Rainfall SMS EDU+RS RS WOS

Pinellas County Homes, Irrigation Nov 06 – Dec 08

62 a

54 a

34 a

22 b

0

2

4

6

8

10

12

14

16

18

200

10

20

30

40

50

60

70

Nov-06 Feb-07 May-07 Sep-07 Dec-07 Mar-08 Jul-08 Oct-08 Jan-09

Mo

nth

ly E

ffe

ctiv

e P

reci

pit

atio

n (i

nch

es)

Irri

gati

on

Ap

plic

atio

n (i

nch

es)

Effective Rainfall SMS EDU+RS RS WOS

Pinellas County Homes, Irrigation Nov 06 – Dec 08

62 a

54 a

34 a

22 b65%

Irrigation Frequency (# Irrig. Events per Month)

Treatment Mean

(#/month)

Std. Dev.

(#/month)

Max

(#/month)

Min

(#/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

0.0

1.0

2.0

3.0

4.0

5.0

6.00.0

0.2

0.4

0.6

0.8

1.0

1.2

May-08 Jun-08 Jul-08 Aug-08 Sep-08

Pre

cip

itat

ion

(in

che

s/d

ay)

Irri

gati

on

Ap

plic

atio

n (

inch

es/

day

)Meter Only Home (not in compliance)

0.0

1.0

2.0

3.0

4.0

5.0

6.00.0

0.2

0.4

0.6

0.8

1.0

1.2

May-08 Jun-08 Jul-08 Aug-08 Sep-08

Pre

cip

itat

ion

(in

che

s/d

ay)

Irri

gati

on

Ap

plic

atio

n (

inch

es/

day

)

Meter Only Home (in compliance)

0.0

1.0

2.0

3.0

4.0

5.0

6.00.0

0.2

0.4

0.6

0.8

1.0

1.2

May-08 Jun-08 Jul-08 Aug-08 Sep-08

Pre

cipi

tati

on (i

nche

s/da

y)

Irri

gati

on A

pplic

atio

n (in

ches

/day

)

Rain Sensor Home0.0

1.0

2.0

3.0

4.0

5.0

6.00.0

0.2

0.4

0.6

0.8

1.0

1.2

May-08 Jun-08 Jul-08 Aug-08 Sep-08

Prec

ipit

atio

n (in

ches

/day

)

Irri

gati

on A

pplic

atio

n (in

ches

/day

)

Soil Moisture Sensor Home

0

50

100

150

200

2500

20

40

60

80

100

120

140

160

180

200

Mo

nth

ly P

reci

pit

atio

n (

mm

)

Irri

gati

on

Ap

plic

atio

n (

mm

)

Effective Rainfall Avg. Irr. Applied (EDU) Calculated Irr. Need

0

50

100

150

200

2500

20

40

60

80

100

120

140

160

180

200

Mo

nth

ly P

reci

pit

atio

n (

mm

)

Irri

gati

on

Ap

plic

atio

n (

mm

)

Effective Rainfall Avg. Irr. Applied (MO) Calculated Irr. Need

0

50

100

150

200

2500

20

40

60

80

100

120

140

160

180

200

Mo

nth

ly P

reci

pit

atio

n (

mm

)

Irri

gati

on

Ap

plic

atio

n (

mm

)

Effective Rainfall Avg. Irr. Applied (RS) Calculated Irr. Need

0

50

100

150

200

2500

20

40

60

80

100

120

140

160

180

200

Mo

nth

ly P

reci

pit

atio

n (

mm

)

Irri

gati

on

Ap

plic

atio

n (

mm

)

Effective Rainfall Avg. Irr. Applied (SMS) Calculated Irr. Need

SMSHomes

Meter Only

Homes

RS + Edu.

Homes

RSHomes

ET CONTROLLER TESTING,

HILLSBOROUGH CO.

ET Controller StudyGCREC 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

GCREC Plot plan

GCREC Rainfall

1.4

8.0

16.0

4.9

6.6

1.1 0.81.8

2.72.1

0.6

3.7

0.0

5.16.5 6.0

4.03.0

8.37.5

8.88.4

3.12.5 2.4

2.9 2.9 3.2

2.2

3.0

8.37.5

8.8 8.4

71.2

91.2

0

10

20

30

40

50

60

70

80

90

100

0

5

10

15

20

25

May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Cu

mu

lati

ve R

ain

fall

(in

)

Mo

nth

ly R

ain

fall

(in

)

Month (2006-2007)

2006-2007

Historical Mean

Cumulative 2006-2007

Cumulative Historical

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?

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

But will ET controllers work in the real world?!

ET Controller Initial Data, SW Fla.Two Sites

0

1

2

3

4

5

6

7

8

9

10

9/26 10/10 10/24 11/7 11/21 12/5 12/19 1/2 1/16

Cu

mu

lati

ve A

vera

ge I

rrig

atio

n A

pp

lied

(i

n)

Date (2008-2009)

Comparison

ET Controllers

Historical Comparison

Historical ET Controllers~50%

Smart Irrigation Controller Irrigation Reduction Potential

Method Location Irrigation

Savings

Weather Funding

agency

Time clock

adjustment w/

rain sensor

Homes in Central

Fla.30% Normal to rainy SJRWMD

Rain sensor Plots in Gainesville 34% Normal to rainy SWFWMD

15% Dry

Soil moisture

sensor controlPlots in Gainesville 70-90% Normal to rainy SWFWMD

Plots in

Gainesville/CitraUp to 40% Dry

Homes in Pinellas Co. 65% Dry (1 d/wk) SWFWMD

ET controllersPlots in Hillsborough

Co.Up to 60% ~Normal

Hillsborough

Co./FDACS

Up to 40% Dry

Homes in

Hillsborough Co.

~50%

(initially)Dry (ET, variance)

The Answer is NOT Only Smart Controllers

• Smart Controllers have water conservation potential but….

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

Irrigation Savings Potential

0

10

20

30

40

50

60

70

80

Time Clock Adjustment

Rain Sensor Soil Moisture Sensor, plots

Soil Moisture Sensor, homes

ET Controller,

plots

ET Controller,

homes

Irri

gati

on S

avin

gs

(%)

Rainy

DryN

o d

ata

No d

ata

No d

ata

So, What’s the Silver Bullet in

Smart Irrigation Control?

BLANK SLIDE

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

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

PAYBACK EXAMPLE

Payback Period, Irrigation MeterAssumes 50% irrigation efficiency; JEA 2009 costs; total annual irrigation of 43”; 50% savings

$0

$500

$1,000

$1,500

$2,000

$2,500

$3,000

$3,500

$4,000

1 2 3 4 5 6 7 8 9 10 11 12

Irri

gati

on S

avin

gs

Month

0.25 ac

0.5 ac

1.0 ac

1.5 ac

2.0 ac

2.5 ac

3.0 ac

$500 installed cost, one SMS controller

Irrigation applied, Irrigation MeterAssumes 50% irrigation efficiency; JEA 2009 costs; total annual irrigation of 43”

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

1 2 3 4 5 6 7 8 9 10 11 12

Landsc

ape Irr

igati

on (

kgal)

Month

0.25 ac

0.5 ac

1.0 ac

1.5 ac

2.0 ac

2.5 ac

3.0 ac

$0

$2,000

$4,000

$6,000

$8,000

$10,000

$12,000

1 2 3 4 5 6 7 8 9 10 11 12

Irri

gati

on S

avin

gs

Month

Payback Period, Potable+SewerAssumes 50% irrigation efficiency; JEA 2009 costs; total annual irrigation of 43”; 50% savings

$500 installed cost, one SMS controller

0.25 ac

0.5 ac

1.0 ac

1.5 ac

2.0 ac

2.5 ac

3.0 ac

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

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.eduhttp://irrigation.ifas.ufl.edu