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IRIGASI IRIGASI CURAHCURAH(SPRINKLER IRRIGATION)(SPRINKLER IRRIGATION)
Dr.IrDr.Ir. . SugengSugeng PrijonoPrijono, MS, MS
DefinitionDefinition
Pressurized irrigation through Pressurized irrigation through
devices called sprinklersdevices called sprinklers
Sprinklers are usually located on Sprinklers are usually located on
pipes called lateralspipes called lateralspipes called lateralspipes called laterals
Water is discharged into the air and Water is discharged into the air and
hopefully infiltrates near where it hopefully infiltrates near where it
landslands
Kesesuaian PemakaianKesesuaian Pemakaian TanamanTanaman
Cocok hampir semua tanaman (pohon, semak, Cocok hampir semua tanaman (pohon, semak, hamparan), dapat disiramkan di atas atau di bawah hamparan), dapat disiramkan di atas atau di bawah kanopikanopi
Tidak cocok untuk beberapa jenis sayuran yang mudah Tidak cocok untuk beberapa jenis sayuran yang mudah rusak karena tetesan airrusak karena tetesan airrusak karena tetesan airrusak karena tetesan air
Kemiringan lahanKemiringan lahan Cocok untuk lahan datar maupun bergelombangCocok untuk lahan datar maupun bergelombang
Tanah Tanah Paling cocok untuk tanah pasiran, tapi cocok untuk Paling cocok untuk tanah pasiran, tapi cocok untuk hampir semua tipe teksturhampir semua tipe tekstur
Air irigasiAir irigasi Cocok untuk air yang bersih dan bebas sedimenCocok untuk air yang bersih dan bebas sedimen
Fixed sprinklerFixed sprinkler
Traveling Volume Gun Sprinkler Irrigating Traveling Volume Gun Sprinkler Irrigating
Travelling gun sprinkler Travelling gun sprinkler
Permanent LateralPermanent Lateral
Laterals are permanently placed Laterals are permanently placed
(enough to irrigate the entire area)(enough to irrigate the entire area)
Laterals are usually buried, with Laterals are usually buried, with
risers or poprisers or pop--up sprinklersup sprinklersrisers or poprisers or pop--up sprinklersup sprinklers
Easily automated and popular for Easily automated and popular for
some agriculture/some agriculture/horthort applicationsapplications
Capital investment can be highCapital investment can be high
SolidsetSolidset sprinklersprinkler
Periodically Moved LateralPeriodically Moved Lateral
Single lateral is moved and used in Single lateral is moved and used in multiple locationsmultiple locations
Examples:Examples:
HandHand--movemoveHandHand--movemove
TowTow--line/skidline/skid--tow (lateral is pulled across tow (lateral is pulled across the field)the field)
SideSide--roll (lateral mounted on wheels that roll (lateral mounted on wheels that roll to move the lateral)roll to move the lateral)
Fairly high labor requirementFairly high labor requirement
Portable SolidPortable Solid--Set Sprinkler SystemSet Sprinkler System
SideSide--roll wheelroll wheel--move sprinkler move sprinkler
SideSide--Roll Sprinkler Lateral Roll Sprinkler Lateral
Moving LateralMoving Lateral
Single lateral moves automatically Single lateral moves automatically
(mounted on wheeled towers)(mounted on wheeled towers)
Examples:Examples:
Center pivots (lateral pivots in a circle)Center pivots (lateral pivots in a circle) Center pivots (lateral pivots in a circle)Center pivots (lateral pivots in a circle)
Linear or lateral move systems (lateral Linear or lateral move systems (lateral
moves in a straight line)moves in a straight line)
Fairly high capital investmentFairly high capital investment
Center Pivot System with Spray Pad SprinklersCenter Pivot System with Spray Pad Sprinklers
Komponen Irigasi CurahKomponen Irigasi Curah
sumber
mainlinepompa
sumber
sprinkler
lateral
Contoh untuk sprinkler tak bergerak
System Components (5) System Components (5)
LateralsLaterals Pipelines that provide water to the sprinklersPipelines that provide water to the sprinklers
May be below, on, or above the groundMay be below, on, or above the ground
RisersRisers Smaller diameter pipes used to bring water from the Smaller diameter pipes used to bring water from the
lateral to the sprinklerlateral to the sprinkler
PurposesPurposes PurposesPurposes
Raises the sprinkler so that the plants won't Raises the sprinkler so that the plants won't interfere with the water jetinterfere with the water jet
Reduces turbulence of the water stream as it Reduces turbulence of the water stream as it reaches the sprinklerreaches the sprinkler
Mainlines and submainsMainlines and submains Pipelines that supply water to the lateralsPipelines that supply water to the laterals
May serve several laterals simultaneouslyMay serve several laterals simultaneously
Impact SprinklersImpact Sprinklers
SprinklersSprinklers
Devices (usually brass or plastic) with one or more Devices (usually brass or plastic) with one or more
small diameter nozzlessmall diameter nozzles
Impact sprinklersImpact sprinklers
Drive or range nozzle (hits sprinkler arm and throws Drive or range nozzle (hits sprinkler arm and throws Drive or range nozzle (hits sprinkler arm and throws Drive or range nozzle (hits sprinkler arm and throws
water out farther)water out farther)
Spreader nozzle (optional; Applies more water close Spreader nozzle (optional; Applies more water close
to the sprinkler)to the sprinkler)
Trajectory anglesTrajectory angles
PartPart--circle sprinklerscircle sprinklers
Used in all types of irrigation, but especially Used in all types of irrigation, but especially
agricultural cropsagricultural crops
Impact SprinklersImpact Sprinklers
RainBird 30 RainBird 14 RainBird 70RainBird 30 RainBird 14 RainBird 70
Impact SprinklersImpact Sprinklers
Impact ArmImpact Arm
Range (Drive) NozzleRange (Drive) Nozzle
TwoTwo--nozzle, bronze impact sprinklernozzle, bronze impact sprinkler
Spreader NozzleSpreader Nozzle
BearingBearing
Trajectory Angle
System Components (2)System Components (2)
GearGear--driven rotors (rotary heads)driven rotors (rotary heads)
Energy in the water turns a turbine that Energy in the water turns a turbine that
rotates the nozzle through a gear trainrotates the nozzle through a gear train
Typically used in large, open landscape Typically used in large, open landscape
areasareasareasareas
TurbineTurbine--driven rotor w/ adjustable spray angledriven rotor w/ adjustable spray angle
Spray Pad devicesSpray Pad devices
Water jet strikes a plate or padWater jet strikes a plate or pad
Pad spreads the water and may be smooth Pad spreads the water and may be smooth
or serratedor serrated
Popular on center pivot and linear move Popular on center pivot and linear move
System Components (3) System Components (3)
Popular on center pivot and linear move Popular on center pivot and linear move
systemssystems
Spray Pad SprinklersSpray Pad Sprinklers
(ozzle(ozzle
Smooth Deflector PadSmooth Deflector Pad Serrated Deflector PadSerrated Deflector Pad
PopPop--Up Spray HeadUp Spray Head
FullFull--circle, 4circle, 4--inch, Popinch, Pop--up spray head w/ Funny Pipe Riserup spray head w/ Funny Pipe Riser
Funny Pipe RiserFunny Pipe Riser
Pipe ThreadPipe Thread--Barb AdaptersBarb Adapters
Spray headsSpray heads
Heads do not rotate Heads do not rotate
Nozzle is shaped to irrigate a certain Nozzle is shaped to irrigate a certain
angle of coverageangle of coverage
Typically used for small or irregularly Typically used for small or irregularly
System Components (4) System Components (4)
Typically used for small or irregularly Typically used for small or irregularly
shaped areasshaped areas
PopPop--up heads are installed flush with up heads are installed flush with
ground and rise when pressurizedground and rise when pressurized
PopPop--up spray head with adjustable coverage up spray head with adjustable coverage
angle from 1 angle from 1 -- 360360
PopPop--up, turbine rotor with riser up, turbine rotor with riser extendedextended
PopPop--Up Turbine Rotor Sprinklers in Up Turbine Rotor Sprinklers in OperationOperation
Kinerja sprinklerKinerja sprinkler
Debit sprinklerDebit sprinkler
Jarak lemparanJarak lemparan
Pola distribusiPola distribusi
RataRata--rata aplikasirata aplikasi RataRata--rata aplikasirata aplikasi
Ukuran tetesan (Ukuran tetesan (dropletsdroplets))
Sprinkler Performance (1)Sprinkler Performance (1)
DischargeDischarge
Depends on type of sprinkler, nozzle size, Depends on type of sprinkler, nozzle size,
and operating pressureand operating pressure
q C D Ps d= 29822
.
qqss = discharge (gpm)= discharge (gpm)
CCdd = discharge coefficient for the nozzle and = discharge coefficient for the nozzle and
sprinkler sprinkler 0.960.96
D = inside diameter of the nozzle (inches)D = inside diameter of the nozzle (inches)
P = water pressure at the nozzle (psi)P = water pressure at the nozzle (psi)
q C D Ps d= 2982.
Diameter of CoverageDiameter of Coverage
Maximum diameter wetted by the sprinkler Maximum diameter wetted by the sprinkler
at a rate that is significant for the intended at a rate that is significant for the intended
useuse
Depends on operating pressure and Depends on operating pressure and
Sprinkler Performance (2) Sprinkler Performance (2)
Depends on operating pressure and Depends on operating pressure and
sprinkler and nozzle design (includingsprinkler and nozzle design (including
trajectory angle)trajectory angle)
Single SprinklerSingle Sprinkler
Pengaruh Tekanan AirPengaruh Tekanan Air
No windNo wind
Elongated parallel pattern
Distribusi air dari sprinklerDistribusi air dari sprinkler
Overlapped Sprinklers Overlapped Sprinklers
Dry zone
Overlapped SprinklersOverlapped Sprinklers
Uniform Application: Uniform Application: Overlap Overlap 50% of 50% of sprinkler wetted sprinkler wetted diameterdiameter
NonNon--uniform uniform Application: Overlap Application: Overlap
Pengaruh Angin thd Jarak Pengaruh Angin thd Jarak SprinklerSprinkler
Application RateApplication Rate
Rectangular sprinkler layoutRectangular sprinkler layout
Aq
S Srs=
96 3.
Ad
t
q
ar= =
AArr = water application rate (inches/hour)= water application rate (inches/hour)
qqss = sprinkler discharge rate (gpm)= sprinkler discharge rate (gpm)
SSll = sprinkler spacing along the lateral = sprinkler spacing along the lateral
(feet)(feet)
SSmm = lateral spacing along the mainline = lateral spacing along the mainline
(feet)(feet)
S Sr l m
Equilateral triangular layoutEquilateral triangular layout
S = spacing between sprinklers (feet)S = spacing between sprinklers (feet)
Aq
Srs=
1112
2
.
Depth of water appliedDepth of water applied
IIgg = A= Arr TToo IIgg = gross depth of water applied per irrigation = gross depth of water applied per irrigation
(inches)(inches)
TToo = actual time of operation (hours)= actual time of operation (hours)
Maximum Spacing of Maximum Spacing of SprinklersSprinklers
Efficiencies Efficiencies
Application efficiency (EApplication efficiency (Eaa))
ddnn = net irrigation depth= net irrigation depth
ddg g = gross irrigation depth= gross irrigation depth
Ed
da
n
g
=
ddg g = gross irrigation depth= gross irrigation depth
fraction or percentagefraction or percentage
Water lossesWater losses EvaporationEvaporation
DriftDrift
RunoffRunoff
Deep percolationDeep percolation
Distribution Distribution UniformityUniformity
Distribution uniformity (DU)Distribution uniformity (DU)
=
zd
dDU
LQ
100
ddLQLQ = average low= average low--quarter depth of water quarter depth of water receivedreceived
ddzz = average depth applied= average depth applied
Popular parameter for surface irrigation Popular parameter for surface irrigation systems in particularsystems in particular
d
Application Uniformity Application Uniformity
Christiansens Coefficient of Uniformity (CU)Christiansens Coefficient of Uniformity (CU)
n = number of observations (each representing the n = number of observations (each representing the
=
=
n
i z
iz
nd
ddCU
1
1100
n = number of observations (each representing the n = number of observations (each representing the same size area)same size area)
ddzz = average depth for all observations= average depth for all observations ddii = depth for observation = depth for observation ii
Popular parameter for sprinkler and Popular parameter for sprinkler and microirrigationmicroirrigation systems in particularsystems in particular
For relatively high uniformities (CU > 70For relatively high uniformities (CU > 70%)%)
Sprinkler Uniformity TestSprinkler Uniformity Test
(catch cans placed on a 5 ft x 5 ft grid)(catch cans placed on a 5 ft x 5 ft grid)
AdequacyAdequacy
Because of Because of nonuniformitynonuniformity, there is a tradeoff , there is a tradeoff between excessive deep percolation and plant between excessive deep percolation and plant water stresswater stress
Adequacy: the percent of the irrigated area that Adequacy: the percent of the irrigated area that receives the desired depth of water or morereceives the desired depth of water or more
Figure Figure 5.3 (a 5.3 (a d)d) Plotting the percentage of area in the field that Plotting the percentage of area in the field that Plotting the percentage of area in the field that Plotting the percentage of area in the field that receives a given depth of irrigation water or more receives a given depth of irrigation water or more gives a distribution uniformity curvegives a distribution uniformity curve
Irrigating for a longer or shorter time moves the Irrigating for a longer or shorter time moves the curve up or down curve up or down
System modifications may be required to change the System modifications may be required to change the shape of the curveshape of the curve
Figure 5.3aFigure 5.3a
SWDSWD
Fig 5.3bFig 5.3b
SWDSWD
Figure 5.3cFigure 5.3c
SWDSWD
Figure 5.3dFigure 5.3d
SWDSWD