evaluating performance of irrigated green space: a review of measures geoff connellan g&m...
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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”.
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.
Water Use and Irrigation Efficiencies
OVERALL IRRIGATION EFFICIENCY
APPLICATION EFFICIENCY
SCHEDULING EFFICIENCY
IRRIGATION EFFICIENCY
How much water gets into the root zone ?
Efficient Delivery into
Root Zone
Aim:
High Application Efficiency
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 up2.Heads assessed according to the potential
fault categories:
Auditing – The Can Test
Uniformity Testing
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 x 100 MWhere:
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 ApplicationCan test readings – Volume (mL)
28 28 40 14.5 D
33 23 34 54 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.
Soil Type Sprinkler Type
Catch CanDULQ
Soil Moisture at
12 cmDULQ
Soil Moisture at
20 cmDULQ
Sandy Loam Rotor 57% 75% 77%
Silty clay loam
Rotor 68% 86% 87%
It is the distribution of water in the soil that is important !
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
4.34.6
7.2
1.8 2.0
3.7
7.8
6.3
5.5
3.1
4.4
6.8
8.1
5.9
4.8
3.9
5.0
5.9
9.4
5.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
Can
1Ca
n 2
Can
3Ca
n 4
Can
5Ca
n 6
Can
7Ca
n 8
Can
9Ca
n 10
Can
11Ca
n 12
Can
13Ca
n 14
Can
15Ca
n 16
Can
17Ca
n 18
Can
19Ca
n 20
mm
Can Number
Series1
BeforeDULQ : 55% SC 25%: 1.8181% extra water required.
RBG System Fix - After
5.5
6.5
7.4
6.3
5.5
6.3
7.8 8.0
7.0
6.1
5.5
6.8
6.3
6.8 6.8
5.0
6.7
8.5
6.3 6.5
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
Can
1
Can
2
Can
3
Can
4
Can
5
Can
6
Can
7
Can
8
Can
9
Can
10
Can
11
Can
12
Can
13
Can
14
Can
15
Can
16
Can
17
Can
18
Can
19
Can
20
mm
Can Number
Series1
After DULQ 79% SC 25% 1.2626% 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.
0
1
2
3
4
5
6
7
1 2 3
Series1
Water Use Reporting
Water Budget Water Used Water Required
0
1
2
3
4
5
6
7
1 2 3
Series1
Water Use Reporting
Water Budget
- Average
Water Used
- Meter
Water Required
- Actual
Inefficiency
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
0
0.5
1
1.5
2
2.5
3
3.5
4
0
50000
100000
150000
200000
250000
300000
*199
3-1
994
199
4-9
5
199
5-9
6
199
6-9
7
199
7-9
8
199
8-9
9
199
9-0
0
200
0-0
1
200
1-0
2
200
2-0
3
200
3-0
4
200
4-0
5
200
5-0
6
200
6-0
7
200
7-0
8
200
8-0
9
200
9-1
0
Irri
gat
ion
Ind
ex
Kil
oli
tres
Financial Year
Irrigation AnnualMeter Total(kl)
Irrigation Index
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 reportRichard Dilena, City of Greater Geelong
1 worse than crop circles v/poorIrrigation index ideal0.9 > 1.1 Visual assessment 2 crop circles poor
underwatering < 0.9 3 large degree of pattern goodoverwatering > 1.1 4 minor degree of pattern v/good
5 completely even excellent% site water budget used
ideal 0.95 to 1.05 ideal +/- 10%minor variation +/- 5% minor +/- 20%major variation +/- 10% or more major > 20%
Irrigation efficiency index -
Performance Parameters1.Irrigation index2.Irrigation efficiency3.Visual assessment4.% of water budget used
Sample: Irrrigated site reportRichard Dilena, City of Greater Geelong
SiteIrrigtaion index (Ii)
Irrigation Effi cienc
y - estimate
d (IEe)
Irrigation Effi ciency - actual
(IE)
Irrigation Effi ciency index
% of Site Water Budget
used
Visual assessme
nt
Anakie Reserve 1.01 75% 74% 0.99 95% 2Bakers Reserve 0.86 80% 93% 1.16 117% 2
Barwon Heads Village Park1.06 75% 71% 0.95 95% 3Breakwater Reserve1.17 75% 64% 0.85 102% 2
Burdoo Reserve 0.90 75% 84% 1.12 90% 5Collendina Reserve0.90 80% 89% 1.11 81% 3
Drysdale Reserve0.81 65% 82% 1.26 72% 3Elderslie Reserve0.96 75% 79% 1.05 90% 3
Flinders Peak 0.82 75% 92% 1.23 77% 2Frier Reserve 0.96 80% 83% 1.04 87% 4
Grinter Reserve 1.03 80% 78% 0.98 92% 4Grovedale Reserve0.98 80% 82% 1.03 88% 2
Hamlyn Park 1.14 80% 70% 0.88 103% 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 HealthRecreation - Green Space
Active Recreation
Passive Recreation
Identifying Services or Outcomes Provided.
Example: Redleap Reserve, Whittlesea
Social Benefits: “User hours or player hours”
Services provided: AFL 11,500 Player hoursCricket 6,700 Player
hoursTotal: 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.
What is the $ value of the benefits?
Photo: Jorge de Arujo, RBG
Efficiency Reference
CSIRO Publishing Website: http://www.publish.csiro.au/pid/5263.htm
Water Use Efficiency For Irrigated Turf and Landscape
Geoff Connellan
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.
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