LAND 331 - Irrigation Exam new
Questions and Answers
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? - Correct Answers -False
Which of the following type of irrigation head is the most optimum selection to be used
for sports turf areas? - Correct Answers -Pop-up Rotary Gear Driven
Which of the following type of irrigation head would require the most pressure to operate
at optimum efficiency? - Correct Answers -Pop-up rotary Impact Driven
T/F: Irrigation nozzle coverage distribution is less uniform with 50% head spacing than
with 65% head spacing - Correct Answers -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. - Correct Answers -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. - Correct Answers -True, drip is typically the most efficient
What is the most efficient irrigation type? - Correct Answers -Drip
What impacts irrgation type efficiceny? - Correct Answers -Exposure to sun, air, wind,
humidity, temperature
Efficiency of Irrigation Types: Spray and Rotor - Correct Answers -67%
Efficiency of Irrigation Types: Bubblers/flood - Correct Answers -75%
Efficiency of Irrigation Types: Drip - Correct Answers -85%
What is the minimum watering requirement for most plant material? - Correct Answers -
Approximately 1" water per week
,DMI microsprays - Correct Answers -short radius, flow measured in GPH, 15-30 PSI, 4-
8 GPH, 2-9' diameter
DMI microbubblers - Correct Answers -connected to PE distribution tubing, short radius,
can be closed off, not pressure compensating, adjustable bubblers
DMI point source emitters - Correct Answers -delivers water directly to the base of the
plant, can easily match plant water needs, pressure compensating, allows design
installation and flexibilty, multiple flow rates (0.5-2 GPH), bug at end to prevent
clogging, installed with a punch of self piercing emitters
how to get total flow on dripline? - Correct Answers -actual flow x the # of emitters (will
give the max gallon per hour of the system)
What is the average watering need during July in Texas? - Correct Answers -about 14"
of water for the month
What is the ideal watering window time? - Correct Answers -3AM to 7AM
Precipitation Rate - Correct Answers -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? - Correct Answers -water quantity,
time, size of area
What is the maximum spacing in average conditions for a spray head? - Correct
Answers -70%
What is the maxiumum spacing in average conditions for a spray head? - Correct
Answers -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? - Correct Answers -2 percent
Things to avoid with sprinkler head spacing? - Correct Answers -do not exceed
manufactures ratings, never stretch a pattern
Head-to-head sprinkler nozzle coverage - Correct Answers -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? - Correct
Answers -Curved Arcs
, Rotary Head Characteristics - Correct Answers -greater than 15' radius, high design
pressure, low precipitation rate
Spray Head Characteristics - Correct Answers -less than 15' radius, low design
pressure, high precipitation rate
T/F: Triangle spacing is more efficient than sqaure/rectangle - Correct Answers -true
What does it mean if two different nozzle head radius' have the same precipitation rate?
- Correct Answers -you can use them in the same zone
Closed Pipe Flow - Correct Answers -pipes flowing full and under pressure (pressurized
flow)
Open Channel Flow - Correct Answers -channels and pipes flowing partially full with the
water surface exposed to the atmosphere; flow driven by gravity (ex: storm drainage)
Pressure - Correct Answers -force exerted over an area
what does PSI stand for - Correct Answers -pounds per square inch
Static water pressure - Correct Answers -is the force transmitted through a closed
conduit and is exerted equally throughout the conduit. Causes a flow when there is an
opening
How much does a cubic foot of water weigh? - Correct Answers -62.4 lbs
how is pressure calculated? - Correct Answers -force divided by area
fps - Correct Answers -feet per second, velocity
GPM - Correct Answers -gallons per minute, measurement of flow
T/F: Assume a water flow of 12 GPM- the pressure loss caused by friction in a pipe of 4"
diameter will be the same as in a pipe with a 2" diameter? - Correct Answers -False,
because the 2" has a higher velocity it will have more friction
What is the most common pipe material for sprinklers? - Correct Answers -plastic
Column of water PSI Calculation - Correct Answers -height of column x .433
ex: height of 10'
10 x .433 = 4.33
Globe Valve - Correct Answers -A valve closed by a disk seating on an opening in an
internal wall. winding flow, more pressure loss, best for regulating flow
Questions and Answers
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? - Correct Answers -False
Which of the following type of irrigation head is the most optimum selection to be used
for sports turf areas? - Correct Answers -Pop-up Rotary Gear Driven
Which of the following type of irrigation head would require the most pressure to operate
at optimum efficiency? - Correct Answers -Pop-up rotary Impact Driven
T/F: Irrigation nozzle coverage distribution is less uniform with 50% head spacing than
with 65% head spacing - Correct Answers -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. - Correct Answers -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. - Correct Answers -True, drip is typically the most efficient
What is the most efficient irrigation type? - Correct Answers -Drip
What impacts irrgation type efficiceny? - Correct Answers -Exposure to sun, air, wind,
humidity, temperature
Efficiency of Irrigation Types: Spray and Rotor - Correct Answers -67%
Efficiency of Irrigation Types: Bubblers/flood - Correct Answers -75%
Efficiency of Irrigation Types: Drip - Correct Answers -85%
What is the minimum watering requirement for most plant material? - Correct Answers -
Approximately 1" water per week
,DMI microsprays - Correct Answers -short radius, flow measured in GPH, 15-30 PSI, 4-
8 GPH, 2-9' diameter
DMI microbubblers - Correct Answers -connected to PE distribution tubing, short radius,
can be closed off, not pressure compensating, adjustable bubblers
DMI point source emitters - Correct Answers -delivers water directly to the base of the
plant, can easily match plant water needs, pressure compensating, allows design
installation and flexibilty, multiple flow rates (0.5-2 GPH), bug at end to prevent
clogging, installed with a punch of self piercing emitters
how to get total flow on dripline? - Correct Answers -actual flow x the # of emitters (will
give the max gallon per hour of the system)
What is the average watering need during July in Texas? - Correct Answers -about 14"
of water for the month
What is the ideal watering window time? - Correct Answers -3AM to 7AM
Precipitation Rate - Correct Answers -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? - Correct Answers -water quantity,
time, size of area
What is the maximum spacing in average conditions for a spray head? - Correct
Answers -70%
What is the maxiumum spacing in average conditions for a spray head? - Correct
Answers -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? - Correct Answers -2 percent
Things to avoid with sprinkler head spacing? - Correct Answers -do not exceed
manufactures ratings, never stretch a pattern
Head-to-head sprinkler nozzle coverage - Correct Answers -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? - Correct
Answers -Curved Arcs
, Rotary Head Characteristics - Correct Answers -greater than 15' radius, high design
pressure, low precipitation rate
Spray Head Characteristics - Correct Answers -less than 15' radius, low design
pressure, high precipitation rate
T/F: Triangle spacing is more efficient than sqaure/rectangle - Correct Answers -true
What does it mean if two different nozzle head radius' have the same precipitation rate?
- Correct Answers -you can use them in the same zone
Closed Pipe Flow - Correct Answers -pipes flowing full and under pressure (pressurized
flow)
Open Channel Flow - Correct Answers -channels and pipes flowing partially full with the
water surface exposed to the atmosphere; flow driven by gravity (ex: storm drainage)
Pressure - Correct Answers -force exerted over an area
what does PSI stand for - Correct Answers -pounds per square inch
Static water pressure - Correct Answers -is the force transmitted through a closed
conduit and is exerted equally throughout the conduit. Causes a flow when there is an
opening
How much does a cubic foot of water weigh? - Correct Answers -62.4 lbs
how is pressure calculated? - Correct Answers -force divided by area
fps - Correct Answers -feet per second, velocity
GPM - Correct Answers -gallons per minute, measurement of flow
T/F: Assume a water flow of 12 GPM- the pressure loss caused by friction in a pipe of 4"
diameter will be the same as in a pipe with a 2" diameter? - Correct Answers -False,
because the 2" has a higher velocity it will have more friction
What is the most common pipe material for sprinklers? - Correct Answers -plastic
Column of water PSI Calculation - Correct Answers -height of column x .433
ex: height of 10'
10 x .433 = 4.33
Globe Valve - Correct Answers -A valve closed by a disk seating on an opening in an
internal wall. winding flow, more pressure loss, best for regulating flow
