This document discusses various methods of energy dissipation in irrigation engineering, focusing on concepts such as hydraulic jumps, stilling basins, and bucket-type energy dissipators. It explains the significance of controlling kinetic energy in water flows to prevent damage to spillways and river beds, detailing the mechanics of hydraulic jumps and the design of stilling basins. Plunge pools are also addressed as energy dissipaters used under specific conditions, emphasizing their construction and scour risks.

1. ENERGY DISSIPATION
IRRIGATION ENGINEERING

2. -:CREATED BY:-
KAVIN RAVAL
141080106026
-:SUBMITED TO:-
PROF. HEMALI DESAI
CIVIL DEPARTMENT
ACET

3. CONTENT
• ENERGY DISSIPATION BELOW SPILLWAY
• HYDRAULIC JUMP
• STILLING BASINS
• BUCKET TYPE ENERGY DISSIPATION
• PLUNGE POOLS

4. ENERGY DISSIPATION BELOW
SPILLWAY
CHAPTER -1

5. ENERGY DISSIPATION BELOW SPILLWAY
• Water flowing over a spillway acquires a lot of kinetic energy because of the
conversion of the potential energy into kinetic energy.
• If the water flowing with such a velocity is discharged into kinetic energy.
• If the water flowing with such a high velocity is discharged into river it will
scour the river bed.
• If the scour is not properly controlled, it may extend backward and may
endanger the spillway and the dam.
• In order to protect the channel bed against scour, the kinetic energy of the water
should be dissipated before it is discharged into the d/s channel.
• For the dissipation of the excessive kinetic energy of water, the following two
methods are commonly adopted.
1. By developing a hydraulic jump
2. By using different types of buckets

6. HYDRAULIC JUMP
CHAPTER - 2

7. HYDRAULIC JUMP
• Hydraulic jump is the sudden rise of water that takes place when the
flow changes from supercritical flow state to the subcritical state.
• When a stream of water moving with a high velocity and low depth
strikes another stream of water moving with low velocity and high
depth, a sudden rise in the surface of water place.
• This phenomenon is called hydraulic jump.
• This is generally accompanied by a large scale turbulence,
dissipating most of the kinetic energy of supercritical flow.
• Such a phenomenon may occur in a canal below a regulating sluice,
at the bottom of the spillway, or at a place where a steep channel
slope turns flat.

8. HYDRAULIC JUMP

9. HYDRAULIC JUMP
• It may be noted that the depth before the jump is always less than
the depth after the jump.
• The depth before the jump is always less than the depth after the
jump is called the initial depth(y1) and the depth after the jump is
called the sequent depth(y2) .
• In the specific energy diagram, the specific energy is minimum at
point C. this depth of water in the channel, corresponding to the
minimum specific energy ( at point C ) is known as critical depth.

10. HYDRAULIC JUMP
Where yc = critical depth
q = discharge per unit width (meter cube/second) = Q/b
g = 9.81 meter/second square
• From the static energy curve,
If y = yc …critical flow
If y1 < yc …supercritical flow
If y2 > yc …subcritical flow

11. HYDRAULIC JUMP FORMATION
• For hydraulic jump to be developed in a horizontal
rectangular channel , the following equation must be
classified.
• For a given discharge intensity over a spillway, the depth
y1 is equal to q/v1 and v1 is determined by the drop H1 as

12. HYDRAULIC JUMP FORMATION

14. HYDRAULIC JUMP FORMATION
JUMP HEIGHT CURVE(J.H.C.)
• y’2 for different discharges,
the tail water depth is found
by actual gauge discharge
observations and by hydraulic
computations. The post jump
depths(y2) for all those
discharges , are also computed
from equation. If a graph is
now plotted between q and y2
, the curve is known as jump
height curve(J.H.C.) or y2
curve.
JUMP WATER CURVE (J.W.C.)
• The actual tail water depth
(y’2) corresponding to any
discharge intensity q will
however depend on the
hydraulic condition of the
river channel on the
downstream side. The
values of y’2
corresponding to different

15. HYDRAULIC JUMP FORMATION

16. Relative Position Of J.H.C. And T.W.C.

17. Simple Horizontal Apron

18. Sloping apron below the bed

19. Sloping Apron Above The Bed

20. Sloping apron combined with stilling
basin

21. Sloping Apron Partly Above And Partly
Below The River Bed

22. Sloping Apron Partly Above And
Partly Below The Ground Level

23. STILLING BASINS
CHAPTER - 3

24. STILLING BASINS
• Stilling basins are external energy dissipators placed at
the outlet of a culvert, chute or rundown.
• These basins are characterized by some combination of
chute blocks, baffle blocks and sills designed to trigger a
hydraulic jump in combination with a required tail water
condition.
• With the required tail water, velocity leaving a properly
designed stilling basin is equal to the velocity in the
receiving channel.
• While various stilling basin designs ODOT practice is to
use the St. Anthony Falls (SAF) stilling basin, which can
operate over a range of approach flow Froude numbers
from 1.7 to 17

25. TYPES OF STILLING BASINS
• [A] U.S.B.R. Stilling basin
1. Type – 1 Basin
2. Type – 2 Basin
3. Type – 3 Basin
• [B] Indian Standard Basin
1. Horizontal Apron Type -1
2. Horizontal Apron Type -2
3. Sloping Apron Type -3
4. Sloping Apron Type -4

26. U.S.B.R. Stilling basin

27. U.S.S.R. Type -1 Stilling Basin

28. U.S.S.R. Type -2 Stilling Basin

29. U.S.S.R. Type -3 Stilling Basin

30. Indian Standard Stilling Basin

31. I.S. Type -1 Basin

32. I.S. Type -2 Basin

33. I.S. Type -3 and Type -4 Basin

34. BUCKET TYPE ENERGY
DISSIPATION
CHAPTER - 4

35. BUCKET TYPE ENERGY DISSIPATION

36. BUCKET TYPE ENERGY DISSIPATION
• Types of bucket type energy dissipation.
1. Solid roller bucket
2. slotted roller bucket
3. ski jump bucket

37. Roller Bucket

38. Solid Roller Bucket Energy Dissipater

39. Slotted Roller Bucket

40. Ski-Jump Bucket

41. Ski Jump Bucket

42. PLUNGE POOLS
CHAPTER - 5

43. Plunge Pools
• Plunge pool is an energy dissipater structure
constructed below water fall or rapids.
• In case of high supercritical flow, swirling of water or
formation of eddies takes place and it is not possible to
dissipate the energy by hydraulic jump type stilling
basin.
• In such cases energy can be dissipated the energy by
plunge pools.

44. Plunge Pools
• Plunge pool can develop as the result of :
-> scour from spillway and bridge abutments
-> jet issued from ski-jump bucket type energy dissipater
-> jet issued from gated spillway
• Plunge pool is constructed in high dam structure. It is not
feasible in case of low dam structure as it is
uneconomical.
• Plunge pool scour involves a significant risk with
trajectory of spillway may cause structural undermining at
the foot of a dam.

45. Plunge Pools
• The plunge pool scour depends upon the following factors
1. Jet velocity
2. Jet shape
3. Air content of the jet
4. Level of tail water
5. Velocity of upstream flow
6. Gradation of sediment

46. Plunge Pools

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