CANAL, TYPES OF CANAL, CANAL LINING

2. CANAL:-
A canal is an artificial channel generally
trapezoidal in shape constructed on the ground
to carry water to the field either from the river
of from a reservoir.

3. Classification of CANAL:-
CANALS
NATURE OF
SOURCE OF
SUPPLY
1. PERMANENT
2. INUNDATION
CANAL
FINANCIAL
OUTPUT
1. PRODUCTIVE
CANAL 2.
PROTECTIVE CANAL
FUNCTION
1. IRRIGATIONAL
CANAL 2. CARRER
CANAL 3. FEEDER
CANAL
4. NAVIGATION
CANAL 5. POWER
CANAL
BOUNDRY
SURFACE
OF CANAL
1. ALLUVIAL
CANAL 2. NON
ALLUVIAL
CANAL 3. RIGID
BOUNDRY
CANAL
DISCHARGE & ITS
RELATIVE
IMPORTANCE
1. MAIN 2. BRANCH
3. MAJOR
DISTRICUTORY
4.MINOR
DISTRUBUTORY
5. WATER COURSE
CANAL
ALIGNMENT
1. CONTOUR
2.WATERSHE
D 3. SIDE
SLOPE

4. Classification of CANAL:-
Classification based on the nature of source of
supply:-
1. Permanent Canal.
2. Inundation Canal.
Classification based on the financial output:-
1. Productive Canal
2. Protective Canal

5. Classification of CANAL:-
 Classification based on function of the canal:-
1. Irrigation Canal
2.Carrier Canal
3. Feeder Canal
4. Navigation Canal
5. Power Canal
 Classification based on boundary surface of canal:-
1. Alluvial Canal
2. Non- Alluvial Canal
3. Rigid Boundary Canal

6. Classification of CANAL:-
 Classification based on discharge and its relative importance
in a given network of canal:-
1. Main Canal.
2. Branch Canal.
3. Major Distributary .
4. Minor Distributary .
5. Water Course .
 Classification based on Canal Alignment:-
1. Contour Canal .
2. Watershed Canal (Ridge Canal).
3. Side Slope Canal.

8. Canal Alignment:-
General consideration for alignment:-
1. It should be aligned in such a way that maximum area is
served with the least length. And its cost including CD- work
is minimum.
2. A shorter length of canal has less loss of head due to friction
and smaller loss of water due to seepage and evaporation, so
that additional area can be brought under cultivation.
3. The alignment should be kept straight as far as possible, it
will result in minimum losses.
4. It should have minimum CD work.

9. Canal Alignment:-
General consideration for alignment:-
5. It should not passes through the village, town, forest or
costly lands, otherwise heavily compensation shall have to
given.
6. It should be such that heavy cutting and feeling
(embankment) are avoided.
7. It should through passes the ridge so that both side of canal
can be irrigated.
8. The alignment should be such that as far as possible a
balanced depth of cutting and filling is achieved.
9. The alignment should not be made in rocky, brackish or
cracked strata.

10. A canal section will be economical when earth work
involved at a particular section has an equal amount of
cut and fill. Usually a canal section has a part in cutting
and part in filling as shown in fig.
If the amount of cut is equal to the amount of fill, it
has to be paid for once only.
Definition:-
For a given C/S there is always only one depth of
cutting for which the cutting and filling will be equal. The
depth is known as balancing depth.
Balancing Depth:-

11. Balancing Depth:-

12. If :-
h = vertical height of top of bank from the bed of canal.
b = bed width of the channel.
t = top width of the canal bank.
n:1 = side slope of bank in filling.
z:1 = side slope of canal in cutting.
d = full supply depth of canal.
y = depth of cutting.
Balancing Depth:-

13. Area of the cut = by + zy2
= y(b + zy)
Area of fill = 2[(h – y)t + n(h-y)2 ]
Equating the area of cut and fill:
y(b + z y) = 2[(h – y)t + n(h-y)2 ]
b y+ zy2 = 2th + 2nh2 – 2nhy – 2ty – 2nhy + 2ny2
y2 (2n – z) – (b + 4nh + 2t)y + 2h(t + nh) =0
From this equation the balancing depth of the canal may
be determined.
Balancing Depth:-

14. A canal is usually constructed with side slope of 1:1 in
cutting and a slope 1.5:1 in filling.
Putting n = 1.5 and z =1 in above equation.
We get;
y2 – (b/2 + 3h + t)y + h (t + 3/2 h)=0
Balancing Depth:-

15. A canal is generally taken in such a way that its section
is partly in cutting and partly in filling in order to
approach close to balancing depth. Many times however
the canal has to be carried through deep cutting or
filling. A canal structure may, therefore, either :
1. In Cutting
2. In Filling
3. In Partial Cutting and Filling.
Cross-section of canal:-

16. Cross-section of canal:-

17. Cross-section of canal:-

18. Cross-section of canal:-

19. Components of canal:-
• Side slopes
• Berms
• Free board
• Land width
• Dowla or Dowel
• Spoil banks
• Borrow pit

20. Components of canal:-
• Side slopes:-
– The side slope constructed on both sides of the canal for
allowing the water to flow in between them. As the canal is
to be constructed in cutting and embankment or both.
Sr. No. Type Of Soil Slope In Cutting Slope In banking
1 Clayey Soil 1.5 : 1 2 : 1
2 Sandy Soil 3 : 1 4 : 1
3 Loamy Soil 1.5 : 1 2 : 1
4 Gravel Soil 0.75 : 1 1.25 : 1
5 Hard Rock 0.25 : 1 ----
6 Soft Rock 0.5 : 1 ----

21. Components of canal:-
• Berms:-
– This is horizontal distance, which is left at G.L.
between the top edge of cutting & toe of bank.
When water flows in the canal at FSL (Full Supply
Level), silt particles are deposited on the berms and
make the final side slope to 1.5:1

22. Components of canal:-
• Free Board:-
– It is the vertical distance between FSL and the top of
bank. It is provided to ensure that water does not
overtop the bank. The magnitude of the free board
in a channel is governed by the consideration of the
channel size and location, rain water inflow wind
action soil characteristics etc.
I.S. 7112- 1973 recommends a minimum freeboard =
0.5m

23. Components of canal:-
• Land Width:-
– The total land required for the construction of
channel is divided into the two parts.
1. Permanent Land
2. Temporary Land

24. Components of canal:-
• Dowel or Dowla:-
– A Dowel or Dowla is provided on the side of a service
road between the service road and channel.
– The top of the dowel is kept above the FSL in the
channel the Dowel are provided as a measure of
safety for automobile driven on the service road.
– They acts as a kerbs on the side of the road way
towards the canal.

25. Components of canal:-
• Spoil Banks:-
–When the quantity of earth obtained from
excavation or cutting is deposited near the
cutting in the form of bank known as spoil
bank.

26. Components of canal:-
• Borrow Pit:-
–When the earth work in filling exceeds
excavated quantity at particular section
borrow pit are required to make good
requirement of filling.

27. Numerical
1. What is balancing depth? Find out the balancing
depth for canal having bed width 18m. FSD of
3m, top width of bank is 6m & 3m side slope in
cutting 1.5 : 1 and in banking 2:1 and freeboard
= 1m.
2. Calculate the economical depth of cutting for
the C/S of canal the bed width is 5m and top
width of banks is 2m. Side slope for excavation
is 1:1 and of banking is 1.5:1. h= 2.92m

29. Canal Lining
• It is the treatment given to the canal bed and
banks to make the canal section impervious. The
lineds
• Canal lining is the process of
reducing seepage loss of irrigation water by
adding an impermeable layer to the edges of the
trench.
• Seepage can result in losses of 30 to 50 percent
of irrigation water from canals, so adding lining
can make irrigation systems more efficient.
Common lining materials include compacted
earth, concrete, and plastic membranes.

30. Advantages of Lining
 Water Conservation:
Lining a canal results in reduction in water losses, as
water losses in unlined irrigation canals can be high.
 No seepage of water into adjacent land or roads:
If canal banks are highly permeable, the seepage of
water will cause very wet or waterlogged conditions, or even
standing water on adjacent fields or roads. Lining of such a
canal can solve this problem.

31. Advantages of Lining
 Canal linings improve command:
Lining makes it possible to maintain high
velocity in the canal. Generally lined canals are
designed with normal value of silt factor (f= 1.2) and
maximum permissible velocity (from 1.8 m/sec to
2.5 m/sec).
For these values of f and V steepest
practicable longitudinal slope may be adopted. Even
then this slope will be flatter than the slope of
unlined canal.

32. Advantages of Lining
Thus this flat slope raises the FSL in general
and brings the high area of land under command
which have not been irrigated before.
Another advantage of maintaining high
velocities can be recognized from the fact that
“lined canals require smaller sections to convey
same amount of water as that carried by unlined
canals”.

33. Advantages of Lining
 Canal linings increase available head for power
generation.
 Canal linings make the canal section stable.
Canal linings prevent bank erosion and breaches.
Canal linings assure economical water
distribution
Canal linings reduce maintenance costs

34. Types of Canal Lining
Hard Surface Lining
Cast Insitu Cement
Concrete Lining
Shotcrete or Plastic
Lining
Cement Concrete Tile
Lining or Brick Lining
Asphaltic Concrete
Lining
Boulder Lining
Earth Type Lining
Compacted Earth
Lining
Soil Cement Lining

35. Exposed and Hard Surface Linings
Earth type canal lining.
Buried Membrane Linings
Types of Canal Lining

36. Exposed and Hard Surface Linings:-
It includes all linings exposed to wear, erosion and
deterioration effect of the flowing water, operation and
maintenance equipment and other hazards.
Such linings are constructed across of cement concrete
and mortars, asphaltic materials, bricks, stones and exposed
membranes.
Although the initial cost of all these linings is generally
high, the reinforced cement concrete linings are costliest
and are usually recommended for use only where structural
safety is the primary consideration
Types of Canal Lining

37. Exposed and Hard Surface Linings:-
1. Cast in situ cement concrete lining
2. Shotcrete or plastic lining.
3. Cement concrete tiles lining or Brick
lining.
4. Asphalt concrete lining.
5. Boulder lining.
6. Exposed Membrane Linings.
Types of Canal Lining

38. Earth type canal lining.
Thick compacted earth lining is durable and can
withstand considerable external hydrostatic pressure.
Bentonite has shown considerable promise for use as
a good lining material.
Bentonite containing large percentage of
montmorillonite, is characterised by high water
absorption accompanied by swelling and
imperviousness. It can be used as 5.0 cm thick
membrane covered by protective blanket or as a
mixed inplace layer of soil bentonite and well
compacted.
Types of Canal Lining

39. Buried Membrane Linings
Hot-applied asphaltic, prefabricated asphalt
materials, plastic film and a layer of bentonite
or other types of clays protected by earth or
gravel cover are cheap linings. These linings
can be provided immediately after completion
of excavation or even later. Membrane linings
are susceptible to damage by weed root and
permissible water velocity is limited to avoid
erosion. The life of the lining is uncertain.
Types of Canal Lining

40. Cast In-situ Cement Concrete Lining

41. Shotcrete & Plastic Lining

42. Canal Lining
CONCRETE LINING

43. Canal Lining
Concrete tiles canal lining

44. Canal Lining
Brick canal lining
PREFABRICATED CHANNEL
SECTION

45. Canal Lining
GEOPOLYMER CANAL LINING