Date post: | 02-Apr-2015 |
Category: |
Documents |
Upload: | alyssa-galford |
View: | 216 times |
Download: | 1 times |
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