Drip Irrigation System Layout & Design

ADVANTAGESWater savingsCrop responseLabour savingsFertilizer savingsLess weed growth

Drip Irrigation System Layout & Design

Saving in pesticidesPossible use of saline waterEarly maturationMinimum soil crustingField edge loss reduction

Drip Irrigation System Layout & Design ADVANTAGES

Improved root penetrationIrrigation of low intake soilsEasy field operation

Drip Irrigation System Layout & Design ADVANTAGES

LIMITATIONSSensitivity to cloggingSalinity hazardsMoisture distribution problemsHigh initial costDry soil & dust formation

Drip Irrigation System Layout & Design

High skill required forDesignInstallationOperationMaintenance

Drip Irrigation System Layout & Design LIMITATIONS

SYSTEM COMPONENTS

Selection criteriaGeneral suitabilityPressure flow characteristicsManufacturing variability

DISCHARGE ELEMENTS (EMITTERS)

Drip Irrigation System Layout & Design

Sensitivity to temperatureResistance to cloggingCostRisk

Drip Irrigation System Layout & Design SYSTEM COMPONENTS

Types- Orifice emitter

q = C A - Tube emitter

q = 0.034 h.78

- Labyrinth emitterq = 0.125 h.78

Drip Irrigation System Layout & Design SYSTEM COMPONENTS

SYSTEM COMPONENTS (Contd.)Lateral linesSub – mainsMain linesMani – foldsFilters

Drip Irrigation System Layout & Design SYSTEM COMPONENTS

PROBLEMS IN FILTRATIONPhysical contaminationChemical contaminationEffect of water sourceFitness of filtration

Drip Irrigation System Layout & Design

FILTERING EQUIPMENT & METHODS

Pressure regulatorsControl valvesMisc. fittings

Drip Irrigation System Layout & Design

DESIGNAmount of water to apply

q = C U . A. σc

qm =

Where :qm is av. Emitter discharge in lph

H is total hr. of operation/dayN is nos. of emitters/ plantq = C U . SI . Sm. σc

Drip Irrigation System Layout & Design

Spacing of emittersRadius of coverage

R = Max. spacing Sl X Sm

Drip Irrigation System Layout & Design DESIGN

Uniformity of water distributionFlow variation < 20%Pressure variation < 20%

Drip Irrigation System Layout & Design DESIGN

Lateral & mainlinesHazen William iq. H = 15.25 X L

H = 5.35 (In decreasing flow lines)

Drip Irrigation System Layout & Design DESIGN

DESIGN CHARTSLateral for uniform slopesLateral for non-uniform slopesSub-mainMain

Drip Irrigation System Layout & Design

Example 1GIVEN :

L = 50 mH = 10 mS = 1%

Emitter spacing = 0.3 mq = 4 lph / emitter

Drip Irrigation System Layout & Design

FIND: Lateral dia.

L/H = 5Q = 4 X 150 = 600 lph = 0.167 lps

FIG. 6 (a)12 mm is acceptable

Drip Irrigation System Layout & Design Example 1

Example 2GIVEN:

L = 120 m Dia = 16 mm

H = 10 m Q = 0.13 lps

Drip Irrigation System Layout & Design

SLOPE:

0 – 30 3% down30 – 60 2% down60 – 90 0% 90 – 120 3% down

Drip Irrigation System Layout & Design Example 2

SOLUTION:

I/L HI (m) HI/ L

0.25 0.90.0075

0.5 1.5 0.01250.75 1.5

0.01251 2.4 0.02

Drip Irrigation System Layout & Design Example 2

Plot I/L vs. HI/ L

OHP 12

H = 5.35 X L

=

Drip Irrigation System Layout & Design Example 2

= 1.5 m

= = .15

L/H = 120/10 = 12

Drip Irrigation System Layout & Design Example 2

Check pressure variation at 4 points at I/L 0.25, 0.5, 0.75, 1. Fig 8

Variations are (QD III)Less than 10%

Drip Irrigation System Layout & Design Example 2

Example 3GIVEN:A= 20 ha Fig 11Subplot = 0.4 haQ = 2 lps / subplot

Drip Irrigation System Layout & Design

Fig 12,Plot mainline profilePlot reqd. pressure headPlot energy line

Use Fig 10 OHP 14 with S = 1 % Find dia of mainlineTable 5

Drip Irrigation System Layout & Design Example 3