Post on 04-Oct-2020
Landscape Irrigation Conservation Research Summary and Future Needs
AWWA Sustainable Water Management Conference Mar. 15-18, 2015, Portland, OR
Michael D. Dukes, PhD., P.E., C.I.D. Agricultural & Biological Engineering
University of Florida/IFAS
clce.ifas.ufl.edu
Single Family Homes Built 0
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2
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7
8
9
100
50,000
100,000
150,000
200,000
250,00020
0020
0120
0220
0320
0420
0520
0620
0720
0820
0920
1020
1120
1220
1320
14
Sing
le F
amily
Hou
sing
Per
mits
FloridaRank
Census pop growth FL 3rd
Florida Population Source: Marella, R.L. 2014. Water Withdrawals, Use and Trends in Florida, 2010. Scientific Investigations Report 2014-5088. U.S. Geological Survey, Washington,
D.C.
Development of Land in Florida
Maps from 1,000 Friends of Florida http://www.1000friendsofflorida.org/planning/2060.asp
Florida Freshwater Withdrawals, 2010
0
500
1000
1500
2000
2500
3000
Wat
er W
ithdr
awal
(MG
D)
SurfaceGround
Irrigation Efficiency: Design/maint. + Management
Non-uniformity(100% uniformitynot practical)Adequate irrigation
Non-uniformity(100% uniformitynot practical)Adequate irrigation
Non-uniformity(100% uniformitynot practical)Adequate irrigation
Under irrigatedUnder irrigatedUnder irrigated
Over irrigationOver irrigation
Root Zone
Soil Below Root Zone
Root Zone
Soil Below Root Zone
Root Zone
Soil Below Root Zone
“Promote Efficient Irrigation”
Misaligned Sprinklers
Broken Sprinklers
Irrigation Efficiency: Design/maint. + Management
Non-uniformity(100% uniformitynot practical)Adequate irrigation
Non-uniformity(100% uniformitynot practical)Adequate irrigation
Non-uniformity(100% uniformitynot practical)Adequate irrigation
Under irrigatedUnder irrigatedUnder irrigated
Over irrigationOver irrigation
Root Zone
Soil Below Root Zone
Root Zone
Soil Below Root Zone
Root Zone
Soil Below Root Zone
Irrigation Requirements
Month
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Dep
th (i
nche
s)
0
2
4
6
8
10
Net Irrig. Req.Efficiency Req.Precip ETc
Turfgrass Annual Gross Irrig. Req. N FL, 33 inches/yr S FL, 43 inches/yr
RAIN SENSORS
IA SWAT Rain Sensor Testing
Long Term Rain Sensor Testing
8
18
32
26
9
5
1 0
8
26
58
8493
99 100 100
0
20
40
60
80
100
120
0
10
20
30
40
50
0-6
6-12
12-1
8
18-2
4
24-3
0
30-3
6
36-4
2
42-4
8
Cum
ulat
ive
freq
uenc
y of
occ
urre
nces
(%)
Freq
uenc
y of
occ
urre
nces
(%)
Interval of hours for dry-out period
Expanding Disk - 3mm setpoint
SMART IRRIGATION CONTROLLERS
Soil Moisture Sensor Controller
Evapotranspiration (ET) Controllers
• Some can determine runtimes and days
• Programming is key! – Soil type – Plant type – Microclimate – Application rates – Slope
EPA WaterSense Protocol Evaluation
0
10
20
30
40
50
60
70
80
Irrig
atio
n Sa
ving
s (%
) RainyDry
Research Based Irrigation Savings Potential
No
data
No
data
No
data
No
data
Smart Controllers – Bottom Line
• They significantly reduce over-irrigation • ET controllers must be targeted to sites
with savings potential • Proper installation enhances savings • Rain sensors do NOT save “in the wild” • Not all technologies are created equal? • Longevity of savings?
LANDSCAPE DESIGN/MODIFICATION
Florida Friendly Landscaping
Estimating SFH Irrigation
• Tampa Bay Water (TBW) • Potable monthly water
billing records for single-family residential for ~12 years
• Parcel records including greenspace
• Soil data (sandy, urban) • Daily rainfall and ET data
Characteristic Observations Variables
Customers ~650,000 -
Monthly water billing
~44,000,000 25
Parcels ~432,000 24
Soils ~40,000 40
Daily weather ~5,782,000 12 24
Individual SFH Irrigation Estimate • Irrigation required based on daily soil-water balance • 1,440 separate calculations for 4,380 days, summed
monthly
Annual ETo (2000) Annual Precipitation (2000) Soil types
25
Identification of FFL Homes
Good FFL…
Good traditional…
0
0.5
1
1.5
2
Irrig
atio
n de
pth
(inch
es)
Month
Good FFL Homes (n=61)
Good Comparison Homes(n=270)
“Good” Quality FFL vs. Neighbors Good FFL mean: 0.52 in/month Good comparison mean: 1.34 in/month FFL savings: 61%
Future Directions
• Education needed to disseminate smart controllers
• Unguaranteed savings mechanisms need verification
• Water rate structures need to keep up • For long term savings, landscape design
will dictate low/no irrigation
mddukes@ufl.edu http://abe.ufl.edu/mdukes/
Acknowledgements: Water Research Foundation, Orange County Utilities, St. Johns River Water Management District, Southwest Florida Water Management District Paper Co-authors: Mackenzie Boyer, Bernardo Cardenas, Melissa Haley, Stacia Davis, Leah Meeks,