The document provides information on diversion head works and their components. It can be summarized as: 1) Diversion head works are structures constructed at the head of a canal to divert river water into the canal and ensure a regulated supply of silt-free water with a minimum head. 2) Key components of diversion head works include under sluices, divide walls, fish ladders, silt exclusion devices, guide banks, and head regulators. Under sluices control silt entry and water levels. Divide walls separate flows. Fish ladders allow fish passage. 3) Site selection factors for diversion head works include suitable foundations, positioning the weir at a right angle to river flow, space for

1. DIVERSION HEAD WORK
Prof. M.B Chougule DKTE’YCP Ichalkaranji

4. .
• diversion head works
• The works which are constructed at the head of the
canal , in order to divert the river water towards the
canal , so as to ensure regulated continuous supply
of silt free water with certain minimum head into
that canal is called as diversion head works.
• These are constructed on a river where adequate
flow of river water is available throughout the year.
• If the storage on upstream of diversion head works
is significant, it is called storage weir
• If it is constructed on downstream of dam for
purpose of diverting water from upstream side of
dam into canal, it is called pick up weir.

5. .
• LOCATION OF DIVERSION HEAD WORK:-
• It should be near the command area. The site which gives economical arrangement
is usually selected.
SITE SELECTION FOR HEAD WORK:-
1) Good foundation should be available.
2) The site should be such that weir can be aligned at right angle to the
diversion of water in the river.
3) The site should be such that there should be sufficient space for location of
head regulator and other component of the diversion headwork.
4) The overall cost should be less.
5) Proper approach way should be nearby site.
6) On the upstream side where water is retained, should not include costly
land.
7) While construction of weir or barrages river should be available near the
site.
8) The material and labours should be available nearby site.
9) The river should be perennial.
10)The river should have non erodible as well as non submersible banks.
11)The site should be narrow and well defined.

6. .
• LAY OUT OF DIVERSION HEAD WORK
• 1) Under Sluice: 2) Divide Wall: 3) Fish ladder:
• 4) Silt exclusion devices: 5) Silt ejectors: 6) Guide bank
• 7) Marginal embankment: 8)canal head regulator 9)weir ( barrage)

7. .
• Weir & Barrage:-
• Weir: It is an impervious barrier constructed across
a river to raise its water level on its upstream side
and divert the water into the canal taking off from
its upstream side.
• Barrage: If storage of water is done by gates and
very small portion or nil portion of water is stored
by raised crest then the barrier is called as barrage.
Barrage is a gate controlled weir. The heading up of
water is effected by the gates alone.
• Weir afflux chances are more in floods.
• Barrage afflux chances are reduced by gates.

10. .
• TPES OF WEIR:-
• 1) gravity weir 2) non gravity weir
• 1) gravity weir
• Depending on material and design features, gravity weirs are subdivided
into following types-
• (i)Vertical drop weir.
• (ii) Sloping weir
• a. Rock fill weirs.
• b. Concrete weirs
• Weirs are also classified as follows :
• (1) According to use and function.
• (a) Storage weir. (b) Pick up weir.
• (c) Diversion weir. (d)Waste weir.
• (2) According to control of surface flow.
• (3) According to the design of floors.
• (4) According to constructional material
• a) Masonry weir
• b) Rockfill weir
• c) Concrete weir

11. .
• Gravity weir:- when the weight of weir balances uplift pressure
caused by the head of water seeping below weir it is called as gravity
weir.
• Non gravity weir:- in non gravity weir the uplift pressure is
largely resisted by weight of concrete slab with the weight of divide
piers.
• i) Vertical Drop Weir:

12. .
• This type of weir consists of horizontal floor and masonry crest with
vertical or nearby vertical downstream face and the shutters are
provided at the crest. Most of the storage is done by raised crest and
some storage by shutters provided over the crest.
• ii) Rock Fill Weir
• It is also called as dry stone slope weir. It is suitable for fine sandy
foundation. stone are mainly used for construction of such type of
weir and hence requires large quantities of stone

13. .
• iii) Concrete Weir:
• These are suitable for permeable foundations. In such weirs sheet
piles are provided on both upstream and downstream floors in order
to destroy the energy of water

14. .
• According to use and function.
• a) Storage Weir :
• It is high weir constructed for storing water. It is also called as
diversion weir. In such weirs shutters may or may not be provided.
• b) Pick Up Weir :
• These are constructed when command area is far away from
reservoir either due to rolling topography or because the land is not
cultivable and if there is broken or rolling topography on one or both
banks of parent river in which construction of canal may be costly.

15. .
• A solid weir usually with crest gates constructed in concrete or stone
masonry located at some distance downstream of dam forming a
large reservoir to raise the water level up to FSL of canal is known as
pickup weir .
• Situations: It is proposed in the following situations-
• i) In case of broken or rolling topography on one or both banks of the
parent river where canal construction is costly.
• ii)In case of command area is too far away from the reservoir may be
due to rolling topography.
• iii) In case of land nearby the reservoir is not cultivable.
• iv) The command area not near the reservoir.
• v) Canal has to run idle.
• Vi) Geographically difficult terrain so that the canal alignment is
• very costly or impossible.

16. .
• c) Diversion Weir:
• A weir which is constructed for diverting the river water into the
canal is called as diversion weir. Generally it is constructed at 900 to
the flow of river.
• D) Waste weir:- it is constructed in continuation of dam . It is
also known as escape channel or a spillway. It allows flood water to
escape and thus ensure safety of the dam.

17. .
• UNDER SLUICE
• Under sluice are opening provided in the body of weir at low level.
• These are located at same side from which canal is taking off. The
crest of under sluice is kept lower than crest of weir due to which
water is attracted towards it and thus ensure easy diversion into
canal.

19. .
• FUNCTIONS OF UNDERSLUICE:-
• 1) it control entry of silt into canal.
• 2) it lowers the HFL.
• 3) it helps in passing low river flood without lifting
shutters.
• 4) it helps to pass silt on downstream side of weir.
• whenever silt is remover the gates of head
regulator are closed and of sluice are opened
through these sluice the silt which is deposited is
removed and it goes on downstream side when all
silt is removed silt gates are closed and regulator
gates are opened.

20. .
• DIVIDE WALL:-
• it is wall constructed between under sluices and
the weir at right angle to the axis of the weir to
divide the river channel.
• Function of divide wall:-
• 1) it separates the under sluices from weir.
• 2) it also helps in reducing velocity of flow near the
head regulator due to which silt is deposited and
clear water passes in to canal.
• 3) it prevents vortices means flow in circular
motion.

23. FISH LADDER
• It is passage provided adjacent to divide wall for the
movement of fish from upstream to downstream
and vice versa.
• It allows free access to fish so that they can travel
from colder water to hot water
• It has been observed that fish moves from old
water to warm water and in monsoon they again
move towards upstream or downstream of the
work.
• These are provided with various fashion like sluice
type in which the baffle wall is in zig zag way over
flow type in which V notches are provided in
staggered arrangement etc.

30. .
• Silt exclusion devices:-
• The device which are constructed at the head of
main canal which prevents entry of silt particles into
canal are called as silt exclusion devices.
• Silt ejectors:-
• The structure which is constructed across the canal
to eject silt accumulated in canal section is called
silt ejector.
• Silt ejector consist of tunnel which is connected
parallel to the flow of the canal and then turns 90
degree to eject silt.
• The length of tunnel provided may be different.
These are provided with sufficient slope. So that silt
should not be deposited in its bed.

34. Silt excluder:-
• It is structure in the under sluices to pass water
containing silt on downstream through under
sluices so that only clear water enters into the the
head regulator.
• These are parallel to the axis of head regulator, silt
excluder prevents the entry of silt into the canal.
• It consist of number of small tunnels with their roof
slab at same level. The crest of the head regulator
and the tunnels are of different length.

36. .
• GUIDE BANK:-
• Guide banks are provided on either side of diversion head work. In alluvial
soil to prevent river from out flanking the work.
• The main object of guide banks are:-
• 1) it prevent oblique approach to the head regulator .
• 2) it protect regulator from river attack.
• 3) it increases maximum discharge at all point.
• 4) it prevent out flanking of structure.
• 5) it create reasonable water way for a weir.
• 6) To separate flow from the scouring weir which is at lower level
• than proper weir.
• 7) To separate the silting packet from scouring sluices
• 8) To prevent formation of cross currents to avoid domain effects
• 9) To cut off the main portion of the river and provide a comparatively
• quite packet in front of the canal head regulator resulting in deposition
• of silt in the pocket and enter clear water in canal

38. Marginal embankment:-
• Marginal embankment are provided on either bank
of river upstream of diversion head work to protect
the land and property which is likely to be
submerged during flood.
• It helps in :-
• 1) reduce the intensity of flood.
• 2) it prevents bed level of the river by silting.
• 3) it protect land and property which is likely to be
submerged.
• SCOURING SLUICE:-
• It helps in scour out the deposited bed silt.

39. .
• HEAD REGULATOR:-
• 1) It regulates the supply of water entering in canal.
• 2) It controls the entry of silt into canal
• 3) It prevents the river flood entering the canal
• Stilling Pond:
• In still can be taken outing pond water made stil
where deposition of silt takes place due to
sedimentation and from which silt can be taken out.
• 1) To reduce velocity of water.
• 2) To settle down the silt and allow clear water to
the canal.

45. .• barrage:- If storage of water is done by gates and very small portion
or nil portion of water is stored by raised crest then the barrier is called as
barrage. the gate controls flow of river depending upon necessity by rising
or lowering the gates. One can construct road way across the river with
minimum cost therefore barrage are always preferred than that of a weir.
• Component parts of barrage:-
• i. Body of barrage ii. Upstream apron
• iii. Upstream curtain wall iv. Downstream apron
• v. Downstream curtain wall vi. Crest vii. Gate / Shutter

48. .
• i. Body of barrage :
• To raise the water level on upstream side.
• ii. Upstream Apron :
• To protect main body of barrage during floods.
• iii. Upstream curtain wall :
• To reduce uplift pressure.
• iv. Downstream Apron :
• To protect downstream bed of river.
• v. Downstream curtain wall :
• To protect downstream and floor from uplift pressure.
• vi. Crest wall:
• To raise water level and divert the water into the canal.
• vii. Gate / Shutter :
• During the floods, the gates are raised to clear off the high
flood level, enabling the high flood to pass downstream with
maximum afflux.
•

49. .
Advantages of Barrage:-
1) Area under submergence of water is less.
2) Cost of rehabilitation is less
3) It is economical as cost of protective and energy dissipation work is less
4) All the stored water can be utilized for irrigation & other purposes.
5) Collected silt in the barrage can be regularly removed hence used with full
capacity throughout its life.
6) as small afflux is caused above HFL the area under flooding is less
7)These are low cost flood banks.
8) More safe that weir as afflux is less.
9) It is economical as cost of protective and energy dissipation is less.
10) More control on flood discharge through gates.
11) Preffered in flat longitudinal sloped region & flow having heavy chances of
silt.
Disadvantages of barrage:-
• 1) Storage capacity is less as compared to dams.
• 2) Maintenance cost is more.
• 3)initial cost is more.

50. .
• Component parts of weir:-
i. Body of weir
ii. Upstream apron
iii. Upstream curtain
wall
iv. Downstream apron
v. Downstream curtain
wall
vi. Crest
vii. Shutter

54. .
i. Body of weir:- it is generally made of masonry. Its function is to raise water level
on upstream side . It should be strong enough to resist water pressure.
ii. Upstream apron :- it protect weir during floods from eroding action. Its length
depends upon discharge of river and weir length it is also help to prevent leakage
in subsoil and it minimizes uplift water pressure if any exist.
iii. Upstream curtain wall :- it is provided to reduce the uplift pressure . Its length
depends upon the nature of soil.
iv. Downstream apron:- downstream apron serves like energy dissipaters. These are
provided for destroying kinetic energy and thus prevent downstream side from
erosion. Its length depends upon the height of fall nature of soil discharge etc.
v. Downstream curtain wall:- it protect downstream floor from uplift pressure. Its
length is depend upon the length of weir.
vi. Crest:- it is the top of the weir. It must be strong and durable as it has to resist
water pressure oftenly during floods. During flood water flows over from the
crest .
vii. Shutter:- shutters are provided at the top of weir. It also helps in raiseng the
water level on upstream of river. Shutters must be strong to resist water
pressure.

55. .

59. a layout of diversion head works