LAND 331 - Irrigation Exam new(100%
Correct)
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? - ANSWERFalse
Which of the following type of irrigation head is the most optimum selection to be used for sports
turf areas? - ANSWERPop-up Rotary Gear Driven
Which of the following type of irrigation head would require the most pressure to operate at
optimum efficiency? - ANSWERPop-up rotary Impact Driven
T/F: Irrigation nozzle coverage distribution is less uniform with 50% head spacing than with 65% head
spacing - ANSWERFalse
T/F: In laying out a triangular sprinkler head pattern at 50% of diameter spacing, the row spacing is
equal to the head spacing. - ANSWERFalse, 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. -
ANSWERTrue, drip is typically the most efficient
What is the most efficient irrigation type? - ANSWERDrip
What impacts irrgation type efficiceny? - ANSWERExposure to sun, air, wind, humidity, temperature
Efficiency of Irrigation Types: Spray and Rotor - ANSWER67%
Efficiency of Irrigation Types: Bubblers/flood - ANSWER75%
Efficiency of Irrigation Types: Drip - ANSWER85%
What is the minimum watering requirement for most plant material? - ANSWERApproximately 1"
water per week
What is the average watering need during July in Texas? - ANSWERabout 14" of water for the month
What is the ideal watering window time? - ANSWER3AM to 7AM
Precipitation Rate - ANSWERthe 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? - ANSWERwater quantity, time, size of area
What is the maximum spacing in average conditions for a spray head? - ANSWER70%
What is the maxiumum spacing in average conditions for a spray head? - ANSWER60%
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? - ANSWER2 percent
Things to avoid with sprinkler head spacing? - ANSWERdo not exceed manufactures ratings, never
stretch a pattern
, Head-to-head sprinkler nozzle coverage - ANSWERspacing 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? - ANSWERCurved Arcs
Rotary Head Characteristics - ANSWERgreater than 15' radius, high design pressure, low precipitation
rate
Spray Head Characteristics - ANSWERless than 15' radius, low design pressure, high precipitation rate
T/F: Triangle spacing is more efficient than sqaure/rectangle - ANSWERtrue
What does it mean if two different nozzle head radius' have the same precipitation rate? -
ANSWERyou can use them in the same zone
Closed Pipe Flow - ANSWERpipes flowing full and under pressure (pressurized flow)
Open Channel Flow - ANSWERchannels and pipes flowing partially full with the water surface
exposed to the atmosphere; flow driven by gravity (ex: storm drainage)
Pressure - ANSWERforce exerted over an area
what does PSI stand for - ANSWERpounds per square inch
Static water pressure - ANSWERis 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? - ANSWER62.4 lbs
how is pressure calculated? - ANSWERforce divided by area
fps - ANSWERfeet per second, velocity
GPM - ANSWERgallons 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? - ANSWERFalse, because the 2" has a higher velocity it
will have more friction
What is the most common pipe material for sprinklers? - ANSWERplastic
Column of water PSI Calculation - ANSWERheight of column x .433
ex: height of 10'
10 x .433 = 4.33
Globe Valve - ANSWERA valve closed by a disk seating on an opening in an internal wall. winding
flow, more pressure loss, best for regulating flow
Why is a globe valve preferred for dirty water? - ANSWERBecause the washer and seat that form the
seal can be easily replaced
Gate Valve - ANSWERA shutoff valve closed by lowering a wedge-shaped gate across the passage,
machined seat relies on the tightness of fit to seal the valve, water flows straight, less pressure loss,
more hydraulically efficient
typically only ON/OFF control only
Correct)
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? - ANSWERFalse
Which of the following type of irrigation head is the most optimum selection to be used for sports
turf areas? - ANSWERPop-up Rotary Gear Driven
Which of the following type of irrigation head would require the most pressure to operate at
optimum efficiency? - ANSWERPop-up rotary Impact Driven
T/F: Irrigation nozzle coverage distribution is less uniform with 50% head spacing than with 65% head
spacing - ANSWERFalse
T/F: In laying out a triangular sprinkler head pattern at 50% of diameter spacing, the row spacing is
equal to the head spacing. - ANSWERFalse, 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. -
ANSWERTrue, drip is typically the most efficient
What is the most efficient irrigation type? - ANSWERDrip
What impacts irrgation type efficiceny? - ANSWERExposure to sun, air, wind, humidity, temperature
Efficiency of Irrigation Types: Spray and Rotor - ANSWER67%
Efficiency of Irrigation Types: Bubblers/flood - ANSWER75%
Efficiency of Irrigation Types: Drip - ANSWER85%
What is the minimum watering requirement for most plant material? - ANSWERApproximately 1"
water per week
What is the average watering need during July in Texas? - ANSWERabout 14" of water for the month
What is the ideal watering window time? - ANSWER3AM to 7AM
Precipitation Rate - ANSWERthe 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? - ANSWERwater quantity, time, size of area
What is the maximum spacing in average conditions for a spray head? - ANSWER70%
What is the maxiumum spacing in average conditions for a spray head? - ANSWER60%
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? - ANSWER2 percent
Things to avoid with sprinkler head spacing? - ANSWERdo not exceed manufactures ratings, never
stretch a pattern
, Head-to-head sprinkler nozzle coverage - ANSWERspacing 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? - ANSWERCurved Arcs
Rotary Head Characteristics - ANSWERgreater than 15' radius, high design pressure, low precipitation
rate
Spray Head Characteristics - ANSWERless than 15' radius, low design pressure, high precipitation rate
T/F: Triangle spacing is more efficient than sqaure/rectangle - ANSWERtrue
What does it mean if two different nozzle head radius' have the same precipitation rate? -
ANSWERyou can use them in the same zone
Closed Pipe Flow - ANSWERpipes flowing full and under pressure (pressurized flow)
Open Channel Flow - ANSWERchannels and pipes flowing partially full with the water surface
exposed to the atmosphere; flow driven by gravity (ex: storm drainage)
Pressure - ANSWERforce exerted over an area
what does PSI stand for - ANSWERpounds per square inch
Static water pressure - ANSWERis 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? - ANSWER62.4 lbs
how is pressure calculated? - ANSWERforce divided by area
fps - ANSWERfeet per second, velocity
GPM - ANSWERgallons 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? - ANSWERFalse, because the 2" has a higher velocity it
will have more friction
What is the most common pipe material for sprinklers? - ANSWERplastic
Column of water PSI Calculation - ANSWERheight of column x .433
ex: height of 10'
10 x .433 = 4.33
Globe Valve - ANSWERA valve closed by a disk seating on an opening in an internal wall. winding
flow, more pressure loss, best for regulating flow
Why is a globe valve preferred for dirty water? - ANSWERBecause the washer and seat that form the
seal can be easily replaced
Gate Valve - ANSWERA shutoff valve closed by lowering a wedge-shaped gate across the passage,
machined seat relies on the tightness of fit to seal the valve, water flows straight, less pressure loss,
more hydraulically efficient
typically only ON/OFF control only
