Evaluating performance of
irrigated green space: A review of
measures
Geoff Connellan
G&M Connellan Consultants.
With information provided by Richard Dilena, City of
Greater Geelong & Peter Symes,
RBG Melbourne.
There are lots of efficiency terms.
Including Water Use Efficiency (WUE)
Ref: Irrigation Insights No 5.
Fairweather, Austin & Hope, NSW Ag. NPSI
WUE “commonly used to describe the
relationship between water (input) and the
agriculture product”
WUE is an Index
WUE is used as a generic label for any
performance indicators used to study water use
in “crop production”.
Water Use and Irrigation Efficiencies
1. Water Use Efficiency
Measure of Landscape Outcomes
delivered per unit of water input.
Strategy: Reduce plant water demand,
E.g. Low water use/efficient species
2. Irrigation Efficiency
Proportion of the water applied, that
is delivered into the plant root zone.
APPLICATION
EFFICIENCY
OVERALL
IRRIGATION
EFFICIENCY
SCHEDULING
EFFICIENCY
IRRIGATION
EFFICIENCY
How much
water gets into
the root zone ?
Aim:
Efficient
Delivery
into
High Application
Efficiency
Root Zone
Aim: High Scheduling Efficiency
Depth and Timing matched to daily ET
ET
Factors affecting Application
Efficiency
Efficiency Demands Uniformity
Assessment Individual Sprinkler Heads
1. Individual heads popped up
2. Heads assessed according to the potential fault
categories:
Uniformity Testing
Auditing – The Can Test
NOTE
This discussion is based on Field or
Operational performance measures.
*Scheduling Coefficients (SC)
and also
*Christiansen Coefficient (CU)
are important, particularly in terms of the
design of systems.
Uniformity Testing - Calculating Field DU
DU (%)
=
M25
M
x 100
Where:
M - average value of all catch can
readings.
M25 - average of lowest 25% of readings.
*Field DU should be greater than 75%.
Precipitation Rate (PR)
(a) Determined from a can test
also
(b) Calculated from sprinkler flow rate
Valuable data
* Validate system performance
* Determine Irrigation Schedule
Calculating Precipitation Rate
Depth
(mm)
Catch can - A very powerful performance tool!
Uniformity of Application
Can test readings – Volume (mL)
28
33
28
23
40
34
14.5
54
D
C
22
23.5
34
35
B
12
30
34
20
A
4
3
2
1
ROWS
Lowest:
12 mL
Highest:
54 mL
Uniformity Results
For example:
New irrigation systems:
Field DU Should be > 75%
Existing systems: If DU < 75% System
should be repaired or adjusted.
Existing systems: If DU < 60% System
should be replaced.
DU as an Efficiency Measure
It is not strictly a measure of efficiency.
It is an Index
Does it matter?
(1)For communication and management
– No.
(2) For scientific analysis and water balance
– Yes.
It is the distribution of water in the soil
that is important !
Soil Type
Sprinkler
Type
Catch Can
DULQ
Soil
Moisture at
12 cm
DULQ
Soil
Moisture at
20 cm
DULQ
Sandy Loam
Rotor
57%
75%
77%
Silty clay
loam
Rotor
68%
86%
87%
Comment: DU as an Efficiency Measure
Example – Low DU and High Efficiency
System with poor uniformity, application depth
less that that required to refill the root zone, all
the water taken up by plant roots.
It is High Efficiency! (By some measures)
RBG System Fix - Before
Before
DULQ : 55%
SC 25%: 1.81
81% extra water
required.
10.0
9.4
9.0
8.1
7.8
8.0
7.2
6.8
7.0
6.3
5.0
5.9
5.5
4.3
4.6
5.9
5.0
4.8
4.4
5.0
3.9
3.7
4.0
Series1
3.1
3.0
1.8 2.0
2.0
1.0
Can Number
Can 20
Can 19
Can 18
Can 17
Can 16
Can 15
Can 14
Can 13
Can 12
Can 11
Can 10
Can 9
Can 8
Can 7
Can 6
Can 5
Can 4
Can 3
Can 2
0.0
Can 1
mm
6.0
RBG System Fix - After
9.0
8.5
7.8
8.0
6.0
8.0
7.4
7.0
7.0
6.5
6.3
5.5
6.3
6.8
6.1
5.5
6.8 6.8
6.7
6.3
6.3
6.5
5.5
5.0
5.0
4.0
Series1
3.0
2.0
1.0
Can Number
Can 20
Can 19
Can 18
Can 17
Can 16
Can 15
Can 14
Can 13
Can 12
Can 11
Can 10
Can 9
Can 8
Can 7
Can 6
Can 5
Can 4
Can 3
Can 2
0.0
Can 1
mm
After
DULQ 79%
SC 25% 1.26
26% extra water
required
Measurement of Water Use
All irrigated sites need to have dedicated
water meters.
Central control and PC
based systems,
together with digital .
flow meters, provide
comprehensive water
use data.
Reporting Water Consumption
1. Volume totals – ML
2.Trends and Reference years - % change,
higher, lower
3. Application Rates (ML/ha) compared to
industry standard.
* Greater exposure of Application Rates
would be beneficial.
Water Use Reporting
Water Budget
Water Used
Water Required
7
6
5
4
Series1
3
2
1
0
1
2
3
Water Use Reporting
Water Budget
Water Used
Water Required
- Average
- Meter
- Actual
Inefficiency
7
6
5
4
Series1
3
2
1
0
1
2
3
Irrigation Index – Efficiency Indicator
The Irrigation Index (Ii)
What is: Water used relative to
Water required (volume)?
.
Reporting Water Use Performance
Irrigation Index RBG Melbourne
4
250000
Irrigation Annual
Meter Total
(kl)
3.5
Irrigation Index
3
200000
150000
2
1.5
100000
1
50000
0.5
Financial Year
2009-10
2008-09
2007-08
2006-07
2005-06
2004-05
2003-04
2002-03
2001-02
2000-01
1999-00
1998-99
1997-98
1996-97
1995-96
0
1994-95
0
*1993-1994
Kilolitres
2.5
Irrigation Index
300000
Case Study
Reserve Irrigation Report
Richard Dilena
City of Greater Geelong
Bakers Reserve, Geelong, Jan 2012
Bakers Reserve, Geelong, Jan 2013
Bakers Reserve, Geelong, Jan 2014
Bakers Reserve Irrigation Report
Bakers Reserve Irrigation Report
Bakers Reserve Irrigation Report
Bakers Reserve Irrigation Report
Anakie Reserve Irrigation Report
Anakie Reserve Irrigation Report
Anakie Reserve Irrigation Report
Sample: Irrrigated site report
Richard Dilena, City of Greater Geelong
Performance Parameters
1. Irrigation index
2. Irrigation efficiency
3. Visual assessment
4. % of water budget used
Irrigation index
0.9 > 1.1
nderwatering < 0.9
overwatering > 1.1
ideal
Irrigation efficiency index ideal 0.95 to 1.05
minor variation +/- 5%
major variation +/- 10% or more
Visual assessment
% site water budget used
ideal
+/- 10%
minor
+/- 20%
major
> 20%
1 worse than crop circles
2 crop circles
3 large degree of pattern
4 minor degree of pattern
5 completely even
v/poor
poor
good
v/good
excellent
Sample: Irrrigated site report
Richard Dilena, City of Greater Geelong
Site
Irrigtaion
index (Ii)
Anakie Reserve 1.01
Bakers Reserve 0.86
rwon Heads Village1.06
Park
Breakwater Reserve
1.17
Burdoo Reserve 0.90
Collendina Reserve
0.90
Drysdale Reserve0.81
Elderslie Reserve0.96
Flinders Peak 0.82
Frier Reserve 0.96
Grinter Reserve 1.03
Grovedale Reserve0.98
Hamlyn Park 1.14
Irrigation
Efficienc Irrigation
yEfficienc Irrigation
estimate y - actual Efficienc
(IE)
y index
d (IEe)
75%
74%
0.99
80%
93%
1.16
75%
71%
0.95
75%
64%
0.85
75%
84%
1.12
80%
89%
1.11
65%
82%
1.26
75%
79%
1.05
75%
92%
1.23
80%
83%
1.04
80%
78%
0.98
80%
82%
1.03
80%
70%
0.88
% of Site
Water
Budget
used
Visual
assessme
nt
95%
117%
95%
102%
90%
81%
72%
90%
77%
87%
92%
88%
103%
2
2
3
2
5
3
3
3
2
4
4
2
3
It is more than the water!
What is the performance of the green space?
Benefits and Value of Irrigated Green Space
(1) Social
(2) Environmental
(3) Economic
Physical Health
Recreation - Green Space
Active Recreation
Passive Recreation
Social Benefits: “User hours or player
hours”
Identifying Services or Outcomes Provided.
Example: Redleap Reserve, Whittlesea
Services provided:
AFL
Cricket
Total:
11,500 Player hours
6,700 Player hours
18,200 Player hours
Water productivity: 3,600 player hours per ML
Exercise/Recreational Benefits
Dept. Health, Vic.
Boeing Reserve, City of Moonee Valley
Stormwater development of site.
Sporting ovals, baseball, grasslands, woodlands
Health Benefits from Green Space
Physical health benefits:
$400,000 (Approx.) per year
Other health benefits
• Mental health: Reduction in stress levels.
• Social benefits: Social cohesion, Liveability,
Reduced rates of violence.
• Environmental benefits: Urban heat island (UHI) mitigation
Cost Benefit Analysis – Green space
Evaluated over 10 years
Community benefit: $4 million (Approx.)
Environmental benefit: $185,000 (Approx.
Costs: $3 million (Approx.)
Net benefit of green space: $0.8 million
RBG Melb. Irrigation Water
Productivity
70 Litres per
visitor.
Photo:
Jorge de
Arujo, RBG
What is the $ value of the benefits?
Efficiency Reference
Water Use Efficiency For
Irrigated Turf and Landscape
Geoff Connellan
CSIRO Publishing Website:
http://www.publish.csiro.au/pid/5263.htm
Summary
1. DU is a powerful measure – It describes the
condition of the system and is an effective
communication tool.
2. Irrigation Index (Ii) - Assesses irrigation
management, scheduling and overall efficiency.
3. Precipitation rate (PR) is valuable in terms of
application efficiency and also in gaining an
understanding of the hydraulic performance of the
system
4. Productivity measures, which assess the services
of the green space, are becoming increasingly
important as the value of green space is recognised.