T E C H L I N E A S ™ D E S I G N G U I D E
NETAFIM @[email protected]
21/12/2009
34
Step 5: Gross Water Requirement (GWR = TWR ÷ Ef%)
GWR = 4,920 ÷ 95%
GWR = 5,178 Litres per week
Step 6: Application Rate(AR)
Refer AR Table – 1.6L/H x 0.3m x0.3m
AR = 17.8mm/Hr
Step 7: Total Zone Flow (TZF = AR x Area m
2
)
TZF = 17.8mm x 200m
2
TZF = 3560 Litres per hour
Step 8: Duration of Irrigation (D = GWR ÷ TZF)
D = 5,178L ÷ 3560L
D = 1.45 Hrs per week
(1.45Hrs x 60 = 87 minutes per week)
Step 9: Soil Infiltration Rate
Soil Type -
Medium
Infiltration rate –
40mm/Hr
Medium Soil –
2 waterings per week (or current watering restrictions)
Duration of Irrigation for this site is
87 minutes
and the application rate of the system is
17.8mm/Hr
. Medium soil has an infiltration rate of
40mm/Hr
so wont require any pulse irrigating.
Note: If the sites soil was heavy pulsing would be required (
approx. 6 x 15 minute cycles
).
Divide the Duration of Irrigation
(
87 minutes
) by the number of days watering should/can take
place
(
2 days
)
to determine the duration of irrigation per day.
87 minutes ÷ 2 days = 43.5 minutes each irrigation day
These steps are designed to serve as a guide only when determining watering regimes. Other
influences may also affect water requirements such as micro climates, wind etc. Always perform
visual checks to ensure your plants are getting enough water.
Netafim Watering Calculator:
A Netafim Water Calculator can be downloaded from the Landscape section
(
http://www.netafim.com.au/index.php?sectionid=3
)of the Netafim Australia website.
The calculator allows you to select relevant data from a range of pop up windows to simply and
quickly determine watering times according to your drip systems output, plant type and current
weather conditions.
