Design of drip irrigation system

Integrated Rural and Agricultural Development Association (IRADA), Satara
Online Training on
“Advanced Irrigation and Precision Agriculture”
Design of Drip Irrigation System
By
Er. R. M. Beldar
M. Tech. (Soil & Water Conservation Engineering)

DRIP IRRIGATION DESIGN
Advanced Irrigation and Precision Agriculture 2
SYSTEM COMPONENTS

Objective of Design
To maintain higher system and Irrigation efficiency means emission uniformity.
To maintain optimum moisture level in soil for optimization of crop yield.
To keep both initial investment and annual cost at minimum level.
To design a suitable type of system which will last and perform well.
To design a manageable system which can be easily operated and maintained.
To satisfy and fulfill the requirements of crops and farmer or users.

Design inputs
Aiming at precise quantity and uniform application of water for each and every plant
Collection of data as detailed below is a prerequisite for designing an efficient MIS.
Engineering Survey Measurement of field, ground slope, contours.
Water Sources Assessment of water sources and availability of water
Agricultural Details Crop, Spacing, type, variety, age, water requirement, crop physiology
Climatological data Temperature, humidity, rainfall, evaporation etc.
Soil and Water analysis Collection of soil & water sample and analysing

steps of Design of drip system
Considering the above parameter, an appropriate MIS has to be design as per steps given below
 System Capacity.
Peak water Requirement of crop
Selection of Emitting Devices or Drippers or Tubing.
 Selection and design of laterals or Tubes.
 Selection and design of Submains.
Selection and design of Mainlines.
Selection and design of filtration system.
Selection and design of Pump Unit.

Design Step drip Irrigation system
DATA COLLECTION
WATER REQUIREMENT CALCULATION
HYDRAULIC DESIGN

X=Tie length
ø
10m
10m
Ø = sin- (X/20)
Total Angle = (2n-4)*90
where, n= no. of sides

Some units about fields
1 cm 10 mm
1 m 100 cm
1 m 3.28 ft
1 ha 10,000 m2
1 ha 2.47 acre = 2.5 acre
1 ha 100 are
1 acre 40 are
1 acre 43560 ft2
1 acre 4047 m2
1 are 1076 ft2 = 1089 ft2
1 are 100 m2
1 km2 100 ha

Data collection
DATA COLLECTION
 WATER SOURCE
Type of Water source – river, canal,
pond, open well etc.
Lowest Water level (LWL)
 METERIOLOGICAL DATA
Daily Average Evaporation, E in mm/d (7-8 mm/d)
Pan Factor, p (0.7)
 OPERATING WINDOW
Electricity available for irrigation, hours
 TOPOGRAPHY
Measurement of field, contours (ground slope)

Data collection
DATA COLLECTION – FARMER INFORMATION
1) Farmer Name:__________________________________
2) Village:____________, Tal:_____________, Dist:___________.
3) Crop :___________
4) Spacing :_____________ (Row to Row and Plant to Plant)
5) Area :___________In acres or Ha
6) Land :________ Flat
7) Water source : Open Well
8) Water level:____________ m B.G.L.
9) Electricity available :_______ In hrs.
10) Pump delivery size:_____”

DATA COLLECTION
 CROP - 1
Crop Name - Orchard
Area, A – ha
Row-Row Spacing, Sr – m
Plant-Plant Spacing , Sp – m
Crop coefficient, kc
Canopy covering Factor, kp
Lateral Spacing, Sr – m
 CROP - 2
Crop Name – Closely spaced
Area, A - ha
Row Spacing , Sp – m
Paired Row Spacing, Sr – m
Crop coefficient, kc
Canopy covering Factor, kp
Lateral Spacing, Sl = Sr + Sp m

Water Requirement of Crop
Before calculating crop water requirement following points to be taken into consideration.
 Type of crop and its age.
Type of soil.
Evaporation loss from the surface.
Transpiration loss from leaves.
Canopy area and root zone development.
Plant to Plant and Row to Row Spacing.
Wind Velocity, Humidity.
Studying all above factors, the month wise and agewise WR for crop decided and design made.
The CWR is equivalent to the rate of evapotranspiration necessary to sustain optimum Plant
growth.

Accuracy of determination of CWR will be depended on Type of Climatic data available.
Evaporation – Loss of Water from soil surface and water Body.
 Transpiration - Loss of Water from Plant surface.
• Evapotranspiration (ET crop) – It is also called Consumptive use.
1) Quantity of water transpired by plant during their growth or retained in the plant tissue.
2) Moisture evaporated from the surface of the soil and Vegetation.
 Reference crop Evapotranspiration (ETo) – Rate of Evapotranspiration from an extended
surface of 8 to 15 tall green grass (Alfa Alfa) cover of uniform height.

Crop Coefficient or Crop factor (Kc)
It is selected for given crop and stage of crop development under prevailing climatic condition.
 The value of Kc depends on foliage characteristics,
stage of growth, environment & geography.
 Horticulture crop - crop factor value - 0.4 to 0.7.
 Wetted Area or % wetted Area or canopy –
It is the area which is shaded due its foliage or canopy cover
when the sun is over head, which depends on the stage of crop
growth.

 1. Net depth of water : i.e. Evapotranspiration of crop (ETP)
ETP = Pe x Pc x Kc
Where,
Pe = Pan evaporation (mm)
Pc = Pan coefficient, taken as 0.7 or 0.8
Kc = Crop Factor
2. Volume of water for Tree crops :
Total volume of water required ( litre / day/ tree)
Net depth of water x % wetted Area coverage by foliage x spacing between tree x spacing between Row
3. Volume of water for Row crops :
Volume of water for required per unit area per day: Net depth of water x Kc x % wetted Area water covered by foliage

Integrated Rural and Agricultural Development Association (IRADA), SataraPWRof different crops

Crop coefficients and Canopy factors of some important crops.

Wetting Pattern
1) Heavy soil 2) Medium soil 3) Light soil

1) Calculate Peak Water Requirement of Crop
Where,
PWR = Peak Water Requirement
A = Evaporation rate (mm/day)
A = Evaporation (E) x Pan coefficient (pc )
Pc = Pan coefficient (0.7 or 0.8 )
B = Crop factor
C = Canopy factor
D = Area (m2) (Row to Row x Plant to plant Specing)
E = Efficiency of drip system (90%)
)//( plantdaylit
E
DCBA
PWR



WATER REQUIREMENT CALCULATION
 PWR For Horticultural Crop
PWR in lit/day = E * Pc * Kc * Kp * Sr * Sp / IE
 PWR For Widely Spaced Row Crop
PWR in mm/day = E * Pc * Kc * Kp / IE

( )
( ) ( ) ( )( )mPPSspacingPlanttoPlant×mRRSspacingRowtoRow
mArea 2
 Total No. of Plants =
 Total PWR = PWR x No. of plants
 No. of Drippers = No. of plants x no. of drippers for each plant

Types of Micro Irrigation System
1. On Line Drip System
4 lph 2 lph
Drippers are required to be fitted on polytube as per plant’s spacing.
Suitable for Horticultural crops (Mango, Orange, Banana, etc.)
8 lph

2. In Line Drip System
a) J Turbo-Line
Emitters are inserted and welded in the tube during extrusion as per pre set plant spacing.
Suitable for Row crops like Sugarcane, Cotton, Tomatoes, Vegetables, etc.
b) J Turbo Aqura

2) HYDRAULIC DESIGN
SELECTION DRIPPER OR EMITTER
Selection of dripper depends upon Crop water requirement or discharge rate, Soil type, infiltration rate, land,
Topography, pressure of system and Cost economy.
----------------------------------------------------------------------------------------------------
Selection Factor : Type of Dripper
----------------------------------------------------------------------------------------------------
1. Type of Crop : Online or Inline
2. Water Requirement : High Discharge or Low Discharge
3 Soil Type : High Discharge or Low Discharge
4. Land Terrain : PC or Non PC
5. Maintenance : Openable or non-openable

2) Selection of Dripper or Emitter
WATER APPLICATION RATE
WAR (lit/hrs.) for Tree crop (Online Drip system).
WAR (mm/hrs.) for Row crops (Inline Emitter system).
 WAR in mm/hrs. = Dripper flow rate / (Lateral spacing * Dripper spacing )
( )l/hrdischargeDripper×/plantDripperofNo.=RatenApplicatioWater

2) Selectionof Dripper or Emitter
( )hr=
WAR
PWR
=TimeIrrigation

2) Selectionof Dripper or Emitter
 AREA TO BE IRRIGATED SIMULTENIOUSLY
 Discharge per Section = Area * Discharge per area / No. of Section
TimeIrrigation
AvailableyElectricit
tionIrrigationofNo sec.

 WATER APPLICATION RATE
WAR in lit/hr = No. of dripper per plant x Dripper flow rate (lit/ hrs.)
WAR in mm/hr = Dripper flow rate / (Lateral spacing * Dripper spacing )
IRRIGATION TIME OR DRIPPER RUN TIME
IT OR DRT in hour = PWR / WAR
AREA TO BE IRRIGATED SIMULTENIOUSLY
No. Of Section = Electricity available / Dripper Run time
Discharge per Section = Area * Discharge per area / No. of Section

3) Selection of Lateral
HYDRAULIC DESIGN
LATERAL SELECTION
Depends upon the Calculate Specific discharge rate ( SDR)
 For tree crop or Online Drip system
 SDR in lph/m = No. of dripper per plant x Dripper flow rate / Sp
OR
 For Row crops / Inline Emitter system.
SDR in lph/m = Dripper flow rate / Dripper spacing along lateral
From SDR Curve, Select diameter of lateral and length of lateral run max.
( ) ( )
( )
)m/lph(
mspacingplanttoPlant
DeargdischDripper×Nplant/dripperofNo
=lateralofSDR
DD

3) Selection of Lateral
HYDRAULIC DESIGN
 LATERAL SELECTION
Discharge of Lateral, Qs – in lps
Hf = (5.35 * Qs
1.852 * Ls) / (D4.871)
Hf < 10 % of working pressure of dripper
Diameters of LLDPE lateral
12mm, 16mm, 20mm, 25mm, 32mm – Plain Polytube
12mm, 16mm, 20mm – Inline tube
16mm, 20mm – PC inline tube

4) Selection of Submain
s/mofLength
plantperdrippersofNo.xdischargeDripperxs/mbycoveredplantsofNo.
m/ofSDR s
s/mofLengthxspacingdripperxspacingLateral
dischargeDripperxs/mbyservedArea
m/ofSDR s

HYDRAULIC DESIGN
Submain Line Selection
Flow or discharge of Submain, Qs – in lps
For Online Dripper system
Qs = (As * WAR) / (Sp * Sr * 3600)
OR
For Inline Emitter system.
Qs = (As * WAR) / 3600
( ) ( )psl
3600
D×N×N
=QSubmainofeargDisch
DDP
sm

HYDRAULIC DESIGN
 SUBMAIN SELECTION
Calculate Frictional Head loss in submain Using Hazen- William Equation
Hf = (5.35 * Qs
1.852 * Ls) / (D4.871)
Hf < 10 % of working pressure of dripper (10 x 10/100)= 1 m
Submain available in PVC Pipe – 40mm, 50mm , 63mm, 75mm, 90mm

Frictional head loss or SDR curve of submain

Integrated Rural and Agricultural Development Association (IRADA), SataraFrictional head loss or SDR curve of submain

 Main line – is conduit which carries water from source to submain
 Designing the mainline following point should be kept in mind.
Permissible Velocity Should not be exceed 1.5 metre per second
Frictional losses Should be limited to 5 to 20 metre per 1000 m length of pipe
Economic Size Should be such that low initial investment, low power cost.
Elevation & Pipe Class Minimise High pressure rating (Class) pipe at elevated ground &Run is short
Control Measure Provide ARV, NRV, PRV & sustaining valves at appropriate location.
5) Selection of main Line

HYDRAULIC DESIGN
 MAIN SELECTION
 Flow in Main = Flow of Submain
From SDR curve select Diameter of mainline and find frictional head loss in m of Main line.
Discharge per section, Q – in lps
Length of Mainline, Lm – in m
Velocity, V – 0.6 to 1.5 m/s
Unit Head loss, Hf - < 20 m/km
Hf = (15.27 * Q1.852 * L) / (D4.871)
Hf < 5 m
( )fh

Flow Diagram for PVC Pressure Pipes & Quick Fix™ Pipes

Flow Diagram for PVC Pressure Pipes & Quick Fix™ Pipes
mm
m
m LD
C
Q
KH 






871.4-
852.1
mH
= Frictional head loss in mainline, (m)
K = Constant, 1.21 x 1010
Qm = Main line discharge, (lps)
C = Friction coefficient for pipe sections
Dm = Inside diameter of main line, (mm)
Lm = Main line length, (m)
mH

Selectionand design of filtrationunit
The selection and design of filtration system is based:
 Source of water.
Type size and concentration of physical impurities.
Design system flow (Filtration capacity).
 Type of irrigation system.
Workability of filtration of system.
Ease for handling, cleaning, maintenance and repairing.
Filtration media and low frictional losses.
Economical investment, maintenance and power cost.

Selectionof filter and fertigation equipment
HYDRAULIC DESIGN
 FILTER UNIT SELECTION
Discharge per section, Q – in (l/s)
Filter Capacity (m3/hrs.) = 3.6 x Flow of main line (Q)
OR
Filter capacity required – 3.6 * Q m³/hr
Select standard capacity of filter which should not be less than required.
Capacity – 15, 20, 25, 40, 50, 60 m³/hr

FERTIGATION EQUIPMENT
Selection of Venturi =
FERTILIZER TANK
Capacity :60lt., 90 lt., 120 lt & 160 lt.
VENTURY INJECTOR
Size : ½”, ¾“, 1”, 2”
INJECTOR PUMP
Size : ¾ “
Proportional Setting of Injection
Rate from 0.5 % to 2 % of Motive Flow
4.1or2
Q
=)psl(flowMotive
main

Selection anddesign of Pump
HYDRAULIC DESIGN
 PUMP SELECTION
Total Head required (H) = (Suction + Delivery) Head + Filtration Losses + Frictional loss in Main Line +
Operating pressure + Fitting losses + Head loss in ventury + Elevation (If any)
OR
Total Head, H = Suction + Delivery head
Filtration head
Operating Pressure of Dripper
Head loss in Main-Submain-Lateral pipe
Fittings (Valves, Tee, Bend, Reducer etc.)
Fertigation loss (Ventury loss)
Elevation (ground slope)

Selection of Total head
 Total head required for the system is calculated as.
Suction Head Vertical distance betn water level to centre of pump.
Delivery Head Vertical distance betn centre of pump to ground level.
Filtration Loss Filtration loss in different type of filter is assumed 2 m for each type of filter
unit. (Hydrocyclone, sand and Screen Filter)
Sand + Screen Filter = 5 m
Main line loss Frictional head losses occur in mainline as per calculation.
Operating Pressure head Given by manufacture at which system has to be operated and designed.
10 m (1Kg/cm2) and 15 m (1.5 Kg/cm2) pressure for NPC & PC dripper respectively
Fitting losses It is assumed to 2 m overall. Fitting like (Elbow, Bend, Tee, reducer, valve, other etc)
Ventury Head It is assumed to 5 m for manually operated ventury. (Certain pressure is required to
operated ventury or fertilizer applicator.
Elevation Vertical distance betn ground level near to source to the highest level of
ground.

HYDRAULIC DESIGN
 PUMP SELECTION
Total Head, H = Suction + Delivery head + Filter loss + Head loss in Main-Submain-Lateral pipe + Operating
Pressure of Dripper + Fittings (Valves, Elbow, Tee, Bend, Reducer etc.) + Ventury loss+Elevation (ground slope)
Horse Power Calculation
Q = Discharge of main per section (lps)
H = Total Head (m)
= Efficiency of Pump (80%)
ba
main HQ
HP
 


75
a = Efficiency of motor (85 %)
b

Data collection
DATA COLLECTION – FARMER INFORMATION
1) Farmer Name: Shri. Vipin Y. Sule
2) Village: Palus , Tal: Palus, Dist: Sangli.
3) Crop :- Mango
4) Spacing :- 20’ x 20’ (Row to Row and Plant to Plant)
5) Area :- L- 100 m & W- 100 m
6) Land :- Flat
7) Water source :- Open Well
8) Water level: - 15 m B.G.L.
9) Electricity available :- 10 hrs.
10) Pump delivery size:- 2”
100 m
100m
W.S

Calculatearea of field
Step 1 Calculate area of field
Length of Field = 100 m
Breadth of field = 100 m
Total Area = L x W = 100 x 100 = 10,000 m2 = 1 ha = 2.47 acre = 100 R

Calculate Peak water requirement
Step 2 Calculate Peak water requirement
A = Evaporation rate (mm/day) = 8.5 mm/day
Pc = Pan coefficient (0.7 or 0.8 )
A = Evaporation (E) x Pan coefficient (pc ) = 8.5 x 0.7 = 5.95 = 6 mm /day
B = Crop factor = 0.65
C = Canopy factor = 0.75
D = (Row to Row x Plant to plant Spacing) = 20’ x 20’ = 20/3.28 = 6.09 m
E = Efficiency of drip system (90%) = 0.9
)//( plantdaylit
E
DCBA
PWR



6 x 0.65 x 0.75 x (6.09 x 6.09)
PWR = --------------------------------
0.9
PWR = 120. 83 Lit/day/plant
)//( plantdaylit
E
DCBA
PWR



269

Considering the cost of Electricity, we will irrigate the field in ONE SECTION

100 m
100m
W.S
50 m50 m
100m
Submain
Lateral

3) Design and Selection of Lateral
( ) ( )
( )
)m/lph(
mspacingplanttoPlant
DeargdischDripper×Nplant/dripperofNo
=lateralofSDR
DD

Frictionalheadlossor SDRcurveof Lateral

s/mofLength
plantperdrippersofNo.xdischargeDripperxs/mbycoveredplantsofNo.
m/ofSDR s
100
269 Nos.
269
100
86.08 (lph/m)
of 100m Which 1.6 m
118m

Section
S/M
nos.
Length of
S/M (m)
Ares covered
by s/m (m2)
No. of plant
covered by
s/m
SDR of S/m
(NDD x ND x
DD) / Length of
s/m
Dia.
(mm)
Class
Hf
(m)
Flow =
(Np x ND x
DD) / 3600
(l/s)
I 1 100 10000 269 86.04 50 III 1.6 2.39
( ) ( )psl
3600
D×N×N
=QSubmainofeargDisch
DDP
sm
269
2.39 lps
2.39 lps

PWR of different crops
Main Line Table.
Flow of submain = flow of Main = 2.39 lps
1 2 3 4 5 6 7 8 9 10 11 12
Section
S/m
nos.
From To
Length
of main
line (m)
Flow =
(Np x ND
x DD) /
3600 (l/s)
Sectional
Flow
Dia.
(mm)
Class
Hf
m/1000
Actual Hf
s/m x 100
(5 x 10)
Sectional
Hf
I 1 s/m WS 50 2.39 2.39 63 II 15/
1000
50 x (15/ 1000) 0.75
Max. head loss in mainline 0.75

Selectionof filter and fertigation equipment
FILTER UNIT SELECTION
Filter Capacity (m3/hrs.) = 3.6 x Flow of main line (Q)
= 3.6 x 2.39 = 8.60 m3/hrs.
Source – Open Well
 Select Sand Filter (J-Filtro Master) 1.5’’ x 20’’, 10 m3/hrs. single with plastic manifold and Manual back washing.
 Select Screen filter (J- super flow filter) 12 m3/hrs. of 1.5’’ inlet.
• Ventury Selection :
MF = 2.39 / 2 = 1.19 l/s
Select ventury complete assembly 1’’
4.1or2
Q
=)psl(flowMotive
main

ba
main HQ
HP
 


75
= 15 + 5 + 0.75 + 10 + 2 + 5 + 0
37.75 m
𝟐.𝟑𝟗 ×𝟑𝟕.𝟕𝟓
𝟕𝟓 ×𝟎.𝟖 ×𝟎.𝟖𝟓
= 𝟏. 𝟕𝟔 HP ≈ 𝟐 𝐇𝐏

Design Layout of Mango Drip system
BV
PVC63mmODClassII
I
Lateral - J- TH 16 mm OD
100 m
100m
Dripper- J- Turbo Key plus- 4
PVC50mmODClassIII
Sand Filter
Venturi
Screen Filter
FV
PumpWS

Dripper Placement diagram
20’
20’
Extension Tube
Dripper

Irrigation scheduling
Total time Required to Irrigate the field is LESS than electricity
available therefore design is fine.
Section S/M No. Flow L/s Sectional Flow Time (hrs.)
I 1 2.39 2.39 3.77
Total Time 3.77

DETAILEDBILLOF QUANTITY
JAIN IRRIGATION SYSTEMS LTD. JALGAON
NAME OF FARMER: Shri. Vipin Y. Sule Crop: Mango
A/P - Palus, Tal : Palus, Dist: Sangali Area : 1 Ha
QUOTATION:-
SR.NO. ITEMS DESCRIPTION QTY UNIT RATE AMOUNT
A PVC PIPE
1 PVC Pipe 63mm Class-II 50 Mtr
2 PVC Pipe 50mm Class-II 102 Mtr
B Lateral, Dripper
2 J-Plan Lateral 16 mm Class-II 1840 Mtr
3 J-Turbo Key plus dripper 8 lph, 4no. 1100 Nos
4 GTO 16 X 13 mm 50 Nos
5 Poly Joiner 16 mm 50 Nos
6 End Cap 16 mm "8" SHAPE 50 Nos
7 Extension Tube 6 mm dia 750 Mtr
8 Short Poly Take off 4 mm dia 600 Nos
9 Long Poly Take off 4 mm dia 0 Nos

C Control Valve
10 PVC Ball Valve 63 mm 0 Nos
11 PVC Ball Valve 50 mm 1 Nos
12 PVC Flush Valve 50 mm 1 Nos
13 PVC ARVC 1’’ 1 Nos
14 ARV Assembly 63`` x 1`` 1 Nos
15 By Pass assembly 2` x 1.5`` 2 Nos
16 Cast iron NRV 2`` 1 Nos
D Filter and Fertigation Equipment
17 Jain filtro master (1.5 x 2) 10 m3/hr 1 Nos
18 Jain Super Flow Filter 12 m3/hr 2"
29 Ventury Compete Assembly 1" 1 Nos
Continued…..

E Fitting's and Accessories
20 PVC FTA 63 mm 2 Nos
21 Elbow 50 mm 2 Nos
22 Reducer 63 x 50 mm 1 Nos
23 Solvent Cement 1/2Lit (250 ml) 1 Nos
24 Teflon tape 2 Nos
TOTAL
GST
SUB Total
Installation Charges(RS. 1000/Acres)
Service Tax @ 12.36% on Installation charge’s
Grand total’s Rs.
Continued…..

Mainline = 50 m, length of 1 pipe = 6 m
Mainline=50/6 = 9 ≈ 9 × 6 = 54 m
In pipe rate are per meter length
Submain length = 100 m, length of 1 pipe = 6 m
Submain=100/6 = 16.60 ≈ 17 × 6 = 102 m
Lateral Length = Area/ RRS =10000/(20/3.28)= 1640 m
Snaking effect 2 % of 1640 = 32.8 m
Lateral for each outlet 1m = 33 m

Total lateral required = 1700 m
Bundle size = 400m
Bundle Quantity = 4
Extra Lateral required 100 m Bundle = 1
No. of Outlet s/m = (Length of s/m)/RRS
= 100/(20/3.28)= 16
Both side
16 x 2 =32 Nos.

GTO (Grommet take off) = 33 ≈ 50 50 GTO/ pack
Polyjoiner = 33 ≈ 50 50PJ/pack
End stop = 33 ≈ 50 50ES/pack
Total Dripper = No. of Plants x 4
= 269 x 4
= 1076
= 1100 Nos. (100D/pack)

Extension tube = No. of plant x 3 m
= 269 x 3
= 807 m
= 1000 m (250m/ bundle)
Poly take off short 4 mm dia. = No. of plant x 2
= 269 x 2
= 538
= 550 50 PTO/pack

Design of drip irrigation system

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