Important topics of Irrigation Engineering : 1. METHOD OF IRRIGATION 2. METHOD OF IRRIGATION SYSTEM 3. CROP GROWING IN GUJARAT 4. DIVERTION HEAD WORKS 5. CANAL REGULATION WORKS 6. CANAL FALLS,CANAL ESCAPE, CANAL OUTLETS 7. DAMS IN INDIA 8. MAJAOR DAMS OF GUJARAT

1. INDEX
1. METHOD OF IRRIGATION
2. METHOD OF IRRIGATION SYSTEM
3. CROP GROWING IN GUJARAT
4. DIVERTION HEAD WORKS
5. CANAL REGULATION WORKS
6. CANAL FALLS,CANAL ESCAPE,
CANAL OUTLETS
7. DAMS IN INDIA
8. MAJAOR DAMS OF GUJARAT

2. METHOD OF IRRIGATION
There are different types of irrigation practised for
improving crop yield. These types of irrigation systems
are practised based on the different types of soils,
climates, crops and resources. The main types of
irrigation followed by farmers include:

3. Surface Irrigation:
In this system, no irrigation pump is involved. Here, water
is distributed across the land by gravity.
1. Flooding method
2. Furrow method
3. Contour farming
1) Flooding method :
Flooding method of irrigation is in use since centuries.
Flooding method consists in applying the water by
flooding the land of rather smooth and flat topography.
In modern irrigation practice several flooding methods
have been developed. In free flooding method water is
applied to the land from field ditches without any check
or guidance to the flow. The method is very clear
from fig.

4. This method is very useful for newly established farms
where making furrows, etc., is very costly. This method
is cheap and can be successfully used where water
supply is in plenty. This method is also well suited for
the fields with very irregular surface which makes
adoption of other methods difficult.
Disadvantage of this method is, as there is no perfect
control over the flow of water it is difficult to attain high
efficiency. Sometimes the flow of water over the soil is
too rapid to fulfil soil moisture deficiency. On the other
hand sometimes water is retained on the field for a
very long time and consequently the water is lost in
infiltration or deep percolation. This method should be
adopted only when other flooding methods are
impossible.

5. 2)Furrow method:
Furrow irrigation is a method of laying out the water
channels in such a way where gravity plays the role of
providing just enough water for suitable plants to grow.
It is usually made by the planned placement of ridges
and furrows. It is a kind of surface irrigation system.
A ridge is the part of the layout of the field that is
elevated at different angles based on the type of soil.
This is actually where the plants are planted. The
furrows are the troughs that let the water flow through
it.

6. 3) Contour farming :
Farming is one of the oldest and sustainable human
activities. As societies evolved from simple to
sophisticated lifestyles, human beings began to till
land and farm in order to produce their own food. As
time passed, man discovered different ways of tilling
and farming on different landscapes, including slopes
that are notorious for soil erosion. Some of the
methods used to date include windbreaks, planting
cover crops, planting grass on waterways, and contour
cultivation among others. Contour cultivation is a
sustainable way of farming where farmers plant crops
across or perpendicular to slopes to follow the
contours of a slope of a field. This arrangement of
plants breaks up the flow of water and makes it harder
for soil erosion to occur.

7. Sub surface irrigation :
Subsurface irrigation uses a network of polyethylene
pipes located just under the ground's surface to apply
disinfected effluent in the root zone of plants,
preventing airborne drift and minimising runoff. Note
that effluent that has not been disinfected, such as
from septic tanks and most wet composting toilets,
must be disposed of below the soil (at least 300
millimetres deep).
Subsurface irrigation requires less maintenance than
surface irrigation, and there is also less chance of
surface saturation and effluent runoff. By reducing the
chance of human contact, it also significantly reduces
the public health risks.

8. Sprinkler irrigation :
In this method an attempt is made to simulate natural
rainfall. Irrigation water is applied to the land in the
form of a spray. This method is also known as
sprinkler irrigation
,
Sprinklers can be used on all soil types of any
topography. According to the equipment and
procedure used the sprinkler method may fall in fixed
type or portable type.

9. Drip irrigation :
It is a latest advancement over other methods. The
name of the method itself implies water saving. In this
method irrigation water is conveyed on the surface in 12
to 16 mm diameter tubing’s fed from large feeder pipes.
The water is allowed to drip or trickle slowly through the
nozzle or orifices at practically zero pressure. In this
way the soil in the root-zone of crops is constantly kept
wet.
In Drip system, water supply is done drop by drop
exactly at roots using a hose or pipe. This method can
also be used in regions where water availability is less.

10. METHOD OF IRRIGATION SYSTEM
There are many different types of irrigation systems,
depending on how the water is distributed throughout the
field. Some common types of irrigation systems include:
Surface irrigation
Water is distributed over and across land by gravity, no
mechanical pump involved.
Localized irrigation
Water is distributed under low pressure, through a
piped network and applied to each plant.
Drip irrigation
A type of localized irrigation in which drops of water are
delivered at or near the root of plants. In this type of
irrigation, evaporation and runoff are minimized.
Sprinkler irrigation
Water is distributed by overhead high-pressure
sprinklers or guns from a central location in the field or
from sprinklers on moving platforms.

11. Center pivot irrigation
Water is distributed by a system of sprinklers that move
on wheeled towers in a circular pattern. This system is
common in flat areas of the United States.
Lateral move irrigation
Water is distributed through a series of pipes, each with
a wheel and a set of sprinklers, which are rotated either
by hand or with a purpose-built mechanism. The
sprinklers move a certain distance across the field and
then need to have the water hose reconnected for the
next distance. This system tends to be less expensive
but requires more labor than others.
Sub-irrigation
Water is distributed across land by raising the water
table, through a system of pumping stations, canals,
gates, and ditches. This type of irrigation is most
effective in areas with high water tables.
Manual irrigation
Water is distributed across land through manual labor
and watering cans. This system is very labor intensive.

12. CROP GROWING IN GUJARAT
Gujarat is a state in western India. It has an area of
19.6 million hectare with a coastline of 1,600 km,
most of which lies on the Kathiawar peninsula, and
a population in excess of 60 million.
The state registered 12.8% agricultural growth in
the last five years against the national average of
2%. Gujarat recorded highest decadal agricultural
growth rate of 10.97% among all the Indian states.
The three main sources of growth in Gujarat's
agriculture are from cotton production, the rapid
growth of high-value crops such as fruits and
vegetables, and from wheat production, which saw
an annual average growth rate of 28% between
2000 and 2008.
Table illustrates the current area, productivity and
production statistics of major crops in Gujarat.

13. Other major produce includes rice, wheat, maize,
pearl millet, groundnut, cotton, mustard, sesame,
pigeon pea, green gram, sugarcane, mango,
banana, sapota, lime, guava, tomato, potato, onion,
cumin, garlic, isabgul and fennel.
Latest Crop Production Statistics of Gujarat-2012-13
Area ('000 ha); Production ('000 tonnes); Productivity
(kg/ha); # Production and Productivity in 1000 bales of
180 kg each

14. DIVERTION HEAD WORKS
An irrigation canal takes its supplies from a river or a
stream. In order to divert water from the river into canal it
is necessary to construct certain worksor structures across
the river and at the head of the off taking canal. These
works are known as Diversion headworks
Components of diversion headworks
The various components of diversion headworks are as
follows:
1. Weir or Barrage
2. Divide wall or divide groyne
3. Fish ladder
4. Undersluices or scouring sluices
5. Silt excluder
6. Canal head regulator
7. River training works such as Marginal bunds and
Guide bunds

15. 1. Weir :
A weir is a structure constructed across a river to raise
its water level and divert the eater into the canal. On the
crest of the weirs usually shutters are provided so that
part of the raising up of water is carried out by shutters.
During floods the shutters may be dropped down to
allow water to flow over the crest of the weir. Weir is
usually aligned at right angles to the direction of flow of
the river.
Weirs may be classified according to the material of
construction and certain design features into the
following three types.
• Masonry weirs with vertical drop
• Rockfill weirs with sloping aprons.
• Concrete weirs with a downstream glacis

16. 2.Divide wall or divide groyne :
A divide wall is a long masonry or concrete wall or
groyne (an embankment protected on all sides by stone
or concrete blocks) which is constructed at right angles
to the axis of the weir to separate the undersluices from
the rest of the weir. If two canals take off, one on either
side of the river, then two divide walls are required, one
on each side. The top width of the divide wall is about
1.5 to 2.5m. The divide wall extends on the upstream
side up to a distance little beyond the beginning of the
canal head regulator and on the downstream side up to
the end of the loose protection.

17. 3.Fish ladder & Diversion headworks :
Large rivers have various types of fish, many of which
are migratory. They move from one part of the river to
another according to the season. In our country
generally fish move from upstream to downstream in the
beginning of winter in search of warmth and return
upstream before monsoon for clearer water. Due to the
construction of a weir or barrage across the river such
migration of the fish will be obstructed and if no
arrangement is made in the weir or barrage for this
migration, large scale destruction of the fish life may
take place in the river.Thus to enable the fish to migrate
fish ladder is provided. Since most fish can travel
upstream only if the velocity of flow does not exceed 3
to 3.5 m/s,

18. 4.Undersluices or Scouring sluices:
The undersluices are the openings provided in the weir
wall with their crest at a low level. These openings are
fully controlled by gates. They are located on the same
side as the off taking canal. If two canals take off, one
on either side of the river, then it would be necessary to
provide undersluices on either side of the canal.

19. 5.Silt excluder :
Silt excluders are a type of silt control device which
functions to exclude silt from water to entering the canal.
These devices are particularly provided on the river bed
in front of the head regulator. A silt excluder usually
consists of a number of rectangular tunnels resting on
the floor of the undersluice pocket. The bottom portion
of the tunnels is formed by the floor of undersluice
pocket. The top level portion of the roof of tunnel is kept
same as the level of the crest or sill of the head
regulator. The tunnels are constructed with variable
lengths. The tunnel nearest to the crest is of same
length as the length of the head regulator. But all other
successive tunnels have a decreasing length.

20. 6. Canal Head regulator :
It is a structure constructed at the head of a canal from
the upstream of the weir or barrage constructed. It
consists of number of spans separated by piers which
supports the gates provided for the regulation of water
flow to the canal. The spans ranging from 6 to 8 m are
used with counter balanced steel gates which are
operated manually by winches. Also larger spans are
used if necessary or the condition is economical.

21. 8.Marginal bunds and guide banks :
Marginal bunds or levees are the earthen embankments
which are provided to confine the flood water from the
river within an allowable cross-section and in between
the embankments. Thus the spreading of flood water
beyond these marginal bunds is prevented.
The guide bunds are also a type of earthen
embankments provided to confine the flood water of
alluvial rivers within a reasonable length of waterway
and provide a straight and non-tortuous approach
towards the constructions works across the river. They
are also used to prevent the river from changing its
course and outflanking the construction work

22. CANAL REGULATION WORKS
A canal obtains its share of water from the pool
behind a barrage through a structure called the
canal head regulator.
The various regulation works are :
• Canal falls
• Cross regulator
• Distributary head regulator
• Canal eascapes
• Canal outlet

23. CANAL FALLS,CANAL ESCAPE, CANAL
OUTLETS
Canal falls:
A canal has a designed longitudinal slope but has
to pass through an undulating terrain. When a canal
crosses an area that has a larger natural surface
slope, a canal drop, also called fall in India, has to
be provided suitably at certain intervals

24. Canal escapes :
These are structures meant to release excess
water from a canal, which could be main canal,
branch canal, distributary, minors etc. Though
usually an irrigation system suffers from deficit
supply in later years of its life, situations that might
suddenly lead to accumulation of excess water in a
certain reach of a canal network may occur due to
the following reasons
• Wrong operation of head works in trying to
regulate flow in a long channel resulting in
release of excess water than the total demand
in the canal system downstream.
• Excessive rainfall in the command area leading
to reduced demand and consequent closure of
downstream gates.
Escapes as also built at the tail end of minors at the
far ends of a canal network. These are required to
maintain the required full supply level at the tail end
of the canal branch.
The construction feature of escapes allows it to be
classified in to two types, as described below.

25. 1 Weir or surface escapes :
These are constructed in the form of weirs, without any
gate or shutter (Figure ) and spills over when the water
level of the canal goes above its crest level
2 Sluice or surplus escapes :
These are gated escapes with a very low crest height
(Figure ). Hence, these sluices can empty the canal much
below its full supply level and at a very fast rate. In some
cases, these escapes act as scouring sluices to facilitate
removal of sediment.

26. Canal Outlet :
Outlets are the openings constructed in the banks of
distributaries and minors. Field channel takes off from
this point and gets irrigation water through outlet. It is
also called turnout or sluice in some parts of India. The
field channels below the outlets are maintained by the
cultivators. Once the water comes out of the outlet
irrigation department has no control over it. Further, in a
canal system there are numerous outlets.

27. DAMS IN INDIA
The major dams in India have helped the inhabitants in
a number of ways like:
1. Providing adequate water for domestic, industry and
irrigation purposes.
2. Hydroelectric power production and river navigation.
3. These major dams in India and their reservoirs
provide recreation areas for fishing and boating.
4. They have helped in the reduction of floods.

28. The list of some major dams in India have been given
below:

29. Tehri Dam
The Tehri Dam is located in the state of Uttarakhand. It is
the highest Dam in India with a height of 260.5 metres. It
is also listed in the top ten highest dams in the world. This
Dam is situated on the river Bhagirathi.
• Height of the Dam- 260.5 m
• Length of the Dam- 575 m
• Type of Dam- Rock fill
• The reservoir capacity- 21,00,000 acre feet
• Capacity that is installed- 1000 Megawatt

30. Bhakra Nangal Dam
The Bhakra Nangal Dam is located in the state of
Himachal Pradesh and Punjab. It is the largest dam in
India having a height of 225 metres and also in the second
position in the largest dams in all over Asia. It is situated
on the river Sutlej.
• Height of the Dam- 226 m
• Length of the Dam- 520m
• Type of Dam- Concrete Gravity
• The reservoir capacity- 75,01,775 acre feet
• Capacity that is installed- 1325 Megawatt

31. Hirakud Dam
The Hirakud Dam is located in the state of Orissa. It is the
longest dam in India with a total length of 25.79 km. It is
also in the list of the longest dams in the world. The
Hirakud Dam is situated on the river Mahanadi.
• Height of the Dam- 61 m
• Length of the Dam- 4.8 km (Main Dam)
• Type of Dam- Composite Dam
• The reservoir capacity- 47,79,965 acre feet
• Capacity that is installed- 347.5 Megawatt

32. Nagarjuna Sagar Dam
The Nagarjuna Sagar Dam is located in the state of
Telangana. It is India’s largest Masonry Dams built till
date. It is the largest manmade lake in the world. It has 26
gates and is 1.55 km in length. It is situated on the river
Krishna.
• Height of the Dam- 124m
• Length of the Dam- 4863 m (Total Lenght)
• Type of Dam- Masonry Dam
• The reservoir capacity- 93,71,845 acre feet
• Capacity that is installed- 816 Megawatt

33. MAJAOR DAMS OF GUJARAT
Sardar Sarovar Dam
The Sardar Sarovar Dam is located in the state of Gujarat.
It is the largest dam in the Narmada Valley Project. This
Dam is to benefit the other neighbouring states of Madhya
Pradesh, Rajasthan and Maharashtra. It is situated on the
river Narmada River.
• Height of the Dam- 163m
• Length of the Dam- 1210m
• Type of Dam- Gravity Dam
• The reservoir capacity- 77,00,000 acre-feet
• Capacity that is installed- 1450 Megawatt

34. Ukai Dam
Ukai Dam is second largest dam in the state and has
largest reservoir in Gujarat known as Vallabh Sagar.
The Dam is constructed across the Tapti river in Surat
district and has second largest storage capacity of
other existing dams in Gujarat.
• Height – 80m
• River - Tapti

35. Kadana Dam
• Kadana Dam is a masonry with embankment dam on
the Mahi river,situated in Panchmahal district. The
dam was built for controlling the floods in the
catchment area.

36. Kamleshwar Dam
Kamleshwar Dam or Hiran I Dam is located inside the Gir
Forest National Park on the Hiran River in Visavadar,
Junagadh district. The Kamleshwar Dam is a rock-fill
embankment dam and the reservoir is famous for crocodiles
and birds.
• Height – 25 m
• River -Hiren