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” Riser“Funny 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 1º angle from 1º -- 360º360º

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= 2982 2.

�� 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 << 50% of sprinkler << 50% of sprinkler wetted diameterwetted diameter

Pengaruh Angin thd Jarak Pengaruh Angin thd Jarak SprinklerSprinkler

Application RateApplication Rate

�� Rectangular sprinkler layoutRectangular sprinkler layout

Aq

S Sr

s=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

Sr

s=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

�� Christiansen’s Coefficient of Uniformity (CU)Christiansen’s 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

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Fig 5.3bFig 5.3b

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Figure 5.3cFigure 5.3c

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Figure 5.3dFigure 5.3d

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