LAND 331 - Irrigation Exam 3
questions fully solved &
updated 2025
T/F: In Texas, any person who is trained as a
landscape architect can provide services to the
public for the design of irrigation systems?
False
Which of the following type of irrigation head is
the most optimum selection to be used for sports
turf areas?
Pop-up Rotary Gear Driven
Which of the following type of irrigation head
would require the most pressure to operate at
optimum efficiency?
Pop-up rotary Impact Driven
T/F: Irrigation nozzle coverage distribution is less
uniform with 50% head spacing than with 65%
head spacing
False
T/F: In laying out a triangular sprinkler head
pattern at 50% of diameter spacing, the row
spacing is equal to the head spacing.
False, row spacing is different with triangular
layout
,T/F: In relative terms, the irrigation efficiency of a
drip system is higher than a spray system.
True, drip is typically the most efficient
What is the most efficient irrigation type?
Drip
What impacts irrgation type efficiceny?
Exposure to sun, air, wind, humidity, temperature
Efficiency of Irrigation Types: Spray and Rotor
67%
Efficiency of Irrigation Types: Bubblers/flood
75%
Efficiency of Irrigation Types: Drip
85%
What is the minimum watering requirement for
most plant material?
Approximately 1" water per week
What is the average watering need during July in
Texas?
about 14" of water for the month
What is the ideal watering window time?
3AM to 7AM
Precipitation Rate
,the average quantity of water in inches applied
during a given period of time over a given area
(in/hr)
What are the three variables of precipitation rate?
water quantity, time, size of area
What is the maximum spacing in average
conditions for a spray head?
70%
What is the maxiumum spacing in average
conditions for a spray head?
60%
When using rotary heads with average winds in
excess of 5 miles per hour, how much should you
reduce the space for each additional MPH?
2 percent
Things to avoid with sprinkler head spacing?
do not exceed manufactures ratings, never stretch
a pattern
Head-to-head sprinkler nozzle coverage
spacing between heads is 50% of the diameter that
the heads can cover- or equal to the design radius
of the nozzle
What is one of the most difficult spaces to cover
with sprinkler heads?
Curved Arcs
Rotary Head Characteristics
, greater than 15' radius, high design pressure, low
precipitation rate
Spray Head Characteristics
less than 15' radius, low design pressure, high
precipitation rate
T/F: Triangle spacing is more efficient than
sqaure/rectangle
true
What does it mean if two different nozzle head
radius' have the same precipitation rate?
you can use them in the same zone
Closed Pipe Flow
pipes flowing full and under pressure (pressurized
flow)
Open Channel Flow
channels and pipes flowing partially full with the
water surface exposed to the atmosphere; flow
driven by gravity (ex: storm drainage)
Pressure
force exerted over an area
what does PSI stand for
pounds per square inch
Static water pressure
questions fully solved &
updated 2025
T/F: In Texas, any person who is trained as a
landscape architect can provide services to the
public for the design of irrigation systems?
False
Which of the following type of irrigation head is
the most optimum selection to be used for sports
turf areas?
Pop-up Rotary Gear Driven
Which of the following type of irrigation head
would require the most pressure to operate at
optimum efficiency?
Pop-up rotary Impact Driven
T/F: Irrigation nozzle coverage distribution is less
uniform with 50% head spacing than with 65%
head spacing
False
T/F: In laying out a triangular sprinkler head
pattern at 50% of diameter spacing, the row
spacing is equal to the head spacing.
False, row spacing is different with triangular
layout
,T/F: In relative terms, the irrigation efficiency of a
drip system is higher than a spray system.
True, drip is typically the most efficient
What is the most efficient irrigation type?
Drip
What impacts irrgation type efficiceny?
Exposure to sun, air, wind, humidity, temperature
Efficiency of Irrigation Types: Spray and Rotor
67%
Efficiency of Irrigation Types: Bubblers/flood
75%
Efficiency of Irrigation Types: Drip
85%
What is the minimum watering requirement for
most plant material?
Approximately 1" water per week
What is the average watering need during July in
Texas?
about 14" of water for the month
What is the ideal watering window time?
3AM to 7AM
Precipitation Rate
,the average quantity of water in inches applied
during a given period of time over a given area
(in/hr)
What are the three variables of precipitation rate?
water quantity, time, size of area
What is the maximum spacing in average
conditions for a spray head?
70%
What is the maxiumum spacing in average
conditions for a spray head?
60%
When using rotary heads with average winds in
excess of 5 miles per hour, how much should you
reduce the space for each additional MPH?
2 percent
Things to avoid with sprinkler head spacing?
do not exceed manufactures ratings, never stretch
a pattern
Head-to-head sprinkler nozzle coverage
spacing between heads is 50% of the diameter that
the heads can cover- or equal to the design radius
of the nozzle
What is one of the most difficult spaces to cover
with sprinkler heads?
Curved Arcs
Rotary Head Characteristics
, greater than 15' radius, high design pressure, low
precipitation rate
Spray Head Characteristics
less than 15' radius, low design pressure, high
precipitation rate
T/F: Triangle spacing is more efficient than
sqaure/rectangle
true
What does it mean if two different nozzle head
radius' have the same precipitation rate?
you can use them in the same zone
Closed Pipe Flow
pipes flowing full and under pressure (pressurized
flow)
Open Channel Flow
channels and pipes flowing partially full with the
water surface exposed to the atmosphere; flow
driven by gravity (ex: storm drainage)
Pressure
force exerted over an area
what does PSI stand for
pounds per square inch
Static water pressure
