Irrigation Engineering “N.N. Bassak” Irrigation Engineering and Hydraulic structure “Santosh Kumar Garg” Principal of Irrigation Engineering “Frederick Haynes Newell and Daniel William Murphy”

1. Lecture note Prepared By: Nasir Ahmad Aryanfar
Year : 1402/2023
Chapter one
Introduction

2. References
• Irrigation Engineering “N.N. Bassak”
• Irrigation Engineering and Hydraulic structure “Santosh Kumar Garg”
• Principal of Irrigation Engineering “Frederick Haynes Newell and Daniel William
Murphy”

3. Definition of irrigation
IRRIGATION ENGINEERING
The process of artificial application of water to the soil for the growth of
agricultural crops

4. BASICS IN IRRIGATION ENGINEERING
IRRIGATION ENGINEERING: This involves
Conception,
Planning,
Design,
Construction,
Operation and
Management of an irrigation system.
An irrigation engineer is one who has a long theoretical and practical training in
planning, design, construction, operation and management of irrigation systems.

5. Necessity of Irrigation
1. Insufficient rainfall
2. Uneven distribution of rainfall
3. Improvement of perennial (‫)دائمی‬ crops
4. Development of agriculture in desert area

6. Benefits of Irrigation
1. Yield of crop ‫عملکرد‬
‫محصول‬
2. Protection from famine ‫جلوگیری‬
‫از‬
‫قحطی‬
3. Prosperity of farmers ‫موفقیت‬
‫دهقانان‬
4. Source of revenue ‫منبع‬
‫درآمد‬
5. Navigation ‫جهت‬
‫یابی‬
6. Hydroelectric power generation
7. Water supply
8. General communication
9. Development of fishery

7. Disadvantages of Irrigation
1. Rising of water table
2. Dampness of weather and
Formation of marshy land
3. Loss of valuable lands

8. Irrigation
system
Lift irrigation
Man or
animal power
Doon Mote Persian wheel
Swinging
basket
Rati or pulley Wind lass
Mechanical or
electrical
power
Open well
Shallow tube
well
Deep tube
well
Flow
irrigation
Inundation
irrigation
Perennial
irrigation
Direct
irrigation
Storage
irrigation
System of Irrigation

9. LIFT IRRIGATION
Doon Irrigation
Mote Irrigation
Mechanical left Irrigation

10. Flow irrigation
Inundation Irrigation System

11. Flow irrigation
Perennial Irrigation System
Direct Irrigation System
Storage Irrigation System

12. Weir
barrage
Dam

13. Irrigation Engineering
Chapter One
Seciton.2

14. Methods of
irrigation
Sub-surface
irrigation
Surface
irrigation
Furrow
method
Contour
farming
Flooding
method
Controlled
flooding
Free
flooding
Basin
flooding
Check
flooding
Border strip Zigzag
Uncontrolle
d flooding
Sprinkler
Drip
Irrigation

15. Furrow Method
• In furrow irrigation, only a part of the
land surface (the furrow) is wetted thus
minimizing evaporation loss.
• Furrow irrigation is adapted for row
crops like corn, banana, tobacco,
cabbage. potatoes, cotton, sugarcane,
vegetable etc.
• Irrigation can be by corrugation using
small irrigation streams.
• Furrow irrigation is adapted for
irrigating on various slopes except on
steep ones because of erosion and
bank overflow.

16. Furrow Method

17. Furrow Method

18. Furrow irrigation: Infiltration

19. Furrow irrigation
ADAPTATIONS
1) Medium and fine textured soils
2) Variable water supply
3) Farms with only small amount of
equipment

20. ADVANTAGES
1) High water efficiency
2) Can be used in any row crop
3) Relatively easy install
4) Not expensive to maintain
5) Adapted to most soils
DISADVANTAGES
1) Requirement of skilled labor is more
2) A hazard to operation of machinery
3) Drainage must be provided
Furrow irrigation

21. Contour farming
• Mostly used in hilly area
• Land is divided into horizontal strips
(terraces)
• Small bund are provided at the end
of each terrace
• Very useful for flood control and soil
erosion

24. Contour farming

25. flooding
• The method is suitable where broadcast crops, particularly pastures,
alfalfa, peas and small grains are produced.
ADAPTATIONS
• An abundant supply of water
• Close growing crops
• Soils that do not erode easily
• Soils that is permeable
• Irregular topography
• Areas where water is cheap

26. FLOODING ADVANTAGES
(1) Can be used on shallow soils
(2) Can be employed where expense of leveling is great
(3) Installation and operation costs are low
(4) System is not damaged by livestock and does not interfere with use
of farm implements
DISADVANTAGES
(1) Excessive loss of water by run of and deep percolation
(2) Excessive soil erosion on step land
(3) Fertilizers are eroded from the soil
flooding

27. Free flooding
• Land is divided into small strip by
series of field channel
• Each strip opening controlled by
regulator
• The surplus water drain through the
waste water channel

28. Basin method
• More applicable for orchards ‫باغ‬
‫میوه‬
• The circular channel is known as basin

29. BASIN IRRIGATION ADAPTATIONS
1) Most soil texture
2) High value crops
3) Smooth topography
4) High water value/ha

30. BASIN IRRIGATION ADAPTATIONS
ADVANTAGES
1) Varying supply of water
2) No water loss by run off
3) Rapid irrigation possible
4) No loss of fertilizers and organic manures
5) Satisfactory
DISADVANTAGES
1) If land is not leveled initial cost may be high
2) Suitable mainly for orchids, rice, jute ‫کناف‬ , etc.
3) Except rice, not suitable for soils that disperse easily and readily from a
crus

31. Check flooding
• Area is divided into small plots (check
basin) by check bund

32. Border strips
• Area is divided into series of strip

34. zigzag
• Area is divided into small plot in zigzag
manner

35. Irrigation Engineering
Chapter One
Seciton.3

36. Sub-surface method
• Subsurface irrigation or sub-irrigation may be natural or artificial.
Natural sub surface irrigation is possible where an impervious layer
exists below the root zone. Water is allowed in to series of ditches
dug up to the impervious layer, which then moves laterally and
wets root zone.
• In artificial sub surface irrigation,
perforated or porous pipes are laid out
underground below the root zone and
water is led into the pipes by suitable
means.

38. sprinkler method
• The water is applied to the land in the form of spray like rain.
• the lateral pipe may be perforated at the top and sides.

39. sprinkler method
• Uniform application by “artificial rain”
• Good application efficiencies (0.7 – 0.8) dependent on wind,
temperature, humidity
• Fairly terrain independent (but design must take terrain into
account)
• Can have a low labour content
But
• High investment cost
• High maintenance cost due to pumping
• Can be complex to run

40. sprinkler method

41. sprinkler method
a) Perforation on lateral pipes
b) Fixed nozzles on lateral pipe
c) Rotating sprinkles

43. Drip method

44. Drip irrigation
• Drip irrigation is sometimes called trickle irrigation and involves
dripping water onto the soil at very low rates (2-20 liters/hour) from a
system of small diameter plastic pipes fitted with outlets called
emitters or drippers.
Water is applied close to plants so that only part of the soil in which the
roots grow is wetted, unlike surface and sprinkler irrigation, which
involves wetting the whole soil profile. With drip irrigation water,
applications are more frequent (usually every 1-3 days) than with other
methods and this provides a very favorable high moisture level in the
soil in which plants can flourish.
44

45. 45

46. Drip Irrigation System Requirements
Suitable crops
Drip irrigation is most suitable for row crops (vegetables, soft fruit),
tree where one or more emitters can be provided for each plant.
Generally only high value crops are considered because of the high
capital costs of installing a drip system.
Suitable slopes
Drip irrigation is adaptable to any farmable slope. Normally the crop
would be planted along contour lines and the water supply pipes
(laterals) would be laid along the contour also. This is done to minimize
changes in emitter discharge as a result of land elevation changes.
46

47. 47

48. ‫الکترونیک‬ ‫آموزش‬ ‫کمیته‬ 48

49. Drip Irrigation System Requirements
Suitable soils
Drip irrigation is suitable for most soils. On clay soils water must be applied
slowly to avoid surface water ponding and runoff. On sandy soils higher
emitter discharge rates will be needed to ensure adequate lateral wetting of
the soil.
Drip System Layout
A typical drip irrigation system is shown in Figure 61 and consists of the
following components:
Pump unit
Control head
Main and sub main lines
Laterals
Emitters or drippers.
49

50. 50

51. Drip Irrigation System Requirements
Suitable irrigation water
One of the main problems with drip irrigation is blockage of the emitters. All
emitters have very small waterways ranging from 0.2-2.0 mm in diameter
and these can become blocked if the water is not clean. Thus it is essential
for irrigation water to be free of sediments. If this is not so then filtration of
the irrigation water will be needed.
Blockage may also occur if the water contains algae, fertilizer deposits and
dissolved chemicals which precipitate such as calcium and iron. Filtration
may remove some of the materials but the problem may be complex to solve
and requires an experienced engineer or consultation with the equipment
dealer.
Drip irrigation is particularly suitable for water of poor quality (saline water).
Dripping water to individual plants also means that the method can be very
efficient in water use. For this reason it is most suitable when water is scarce.
51

52. 1. Availability of Irrigation Water
• Any perennial river is available near the command area
• Flood level of inundation river if any
• Investigate the maximum discharge, rainfall to ascertain the total water
requirement
IRRIGATION PROJECT SURVEYING

53. 2. Selection of probable site for barrage or dam
• The river should be straight at least for 1km
• The width of the river should be minimum
• A suitable basin should be available for the storage
• The elevation of the site should be higher than command area
• The storage should not submerged much valuable land
• The capacity should fulfill the total water requirement
IRRIGATION PROJECT SURVEYING

54. 3. Discharge observation for the river
• The daily discharge , max discharge and minimum discharge of the river
• Silt analysis should be carried out in rainy season to determine the natural of
sedimentation
• Discharge observation of all crossing rivers (cross drainage works)
IRRIGATION PROJECT SURVEYING

55. 4. Marking of gross command area and culturable area
• The culturable area should be marked on topographical map
IRRIGATION PROJECT SURVEYING

56. 5. Marking of alignment of main canal
• The alignment of canal should prevent the unnecessary cutting or filling
• The branch of canal should suitable to cover the whole culturable area
• The canal should cross the river, road etc., perpendicularly as much as
possible
• The alignment should not be taken through the valuable land
• The alignment should not pass through the thickly populated areal, religious
places, burial grounds
IRRIGATION PROJECT SURVEYING

57. 6. Preliminary location survey
• The approximate the distance should be measured by pacing
• The objects and the nature of the ground on both sides of alignment
• The alignment should be make to cross the river perpendicularly
• An index map should be prepared for the alignment
IRRIGATION PROJECT SURVEYING

58. 7. Final survey
a) Final location of barrage or dam site
b) Route survey
c) Longitudinal leveling
d) Cross sectional leveling
e) Data for cross drainage work
f) Soil survey
g) Well observation
IRRIGATION PROJECT SURVEYING

59. 8. Preparation of drawings
i. Route survey map
ii. Longitudinal sections
iii. Cross section of main and branch canal
iv. Contour map along the alignment
v. Design of curves with setting out table
IRRIGATION PROJECT SURVEYING

60. 9. Office works
i. Design of canal sections
ii. Detail estimate of earth work
iii. The total land width
iv. Barrage or dam design
v. Detailed report of compensation
vi. Total cost of project
IRRIGATION PROJECT SURVEYING

61. 10. Justification of the selection of final alignment
• Final alignment should be selected based on total cost, working feasibility ,
etc.
IRRIGATION PROJECT SURVEYING

62. 11. Final location survey
• The center line of the main and branch canal should be marked in interval
30m or 50m
• The total land width required for the main and branch canals should be
marked
IRRIGATION PROJECT SURVEYING

63. 1. Introduction
2. Necessity and economic justification (‫)توجیه‬ of the project
3. Report on land acquisition (‫)مالکیت‬ and compensation (‫)عوض‬
4. Detail of design and drawing of hydraulic structures
5. Detailed estimate
6. Specification
7. Availability of material and laborers
8. Communication
9. Submitted maps
10. Conclusion and recommendation
IRRIGATION PROJECT REPORT

64. Next Chapter
Water Requirement of crops
and soil-water relationship