Objective of civil engineering irrigation engineering

MULTIPLE-CHOICE QUESTIONS

I. Select correct options from the questions 1 to 105

1. Which of the following methods of applying water may be used on land with irregular topography?

(a) Free flooding

(b) Border flooding

(d) Furrow irrigation method

ans-a

2. In which of the following methods of applying water to land, ditches are excavated in the field?

(a) Free flooding

(b) Border flooding

(d) Furrow irrigation method

ans-a

3. In border flooding type of water distribution in the forms, the supply ditch is in the form of

(a) earthern channel

(b) lined channel

(d) any one of the above

ans-d

4. In check flooding levees are generally constructed along the contours, having vertical interval of

about

(a) 50 to 100 mm

(b) 100 to 250 mm

(d) 600 to 1000 mm

ans-a

5. The best technique of water distribution in the field that can be used for all types of soils and for

widely different topographies and slopes is

(a) free flooding

(b) border flooding

(d) furrow irrigation method

ans-c

6. Which one of the following is the wrong statement about sprinkler irrigation?

The conditions favouring the adoption of sprinkler irrigation method are

(a) land topography is irregular

(b) land soil is excessively permeable

(d) when water is available with difficulty

ANS- C

7. Sprinkler system is

(a) permanent system

(b) semi-permanent system

(d) any one of the above

ANS-D

8. Which one of the following is the wrong statement about sprinkler system of irrigation?

The advantages of sprinkler irrigation are:

(a) there is no seepage loss.

(b) land leveling is not required.

(d) it is ideally suited for paddy field.

ANS- D

9. The best irrigation method that suits area where scarcity of irrigation water is

(a) sprinkler irrigation

(b) drip irrigation

(d) check flooding

ANS- B

10. In drip irrigation, laterals are usually ______ dia and ______ long.

(a) 25 to 30 mm and 50 m

(b) 25 to 30 mm and 100 m

(d) 10 to 12.5 and 50 m

ANS- D

11. More than ______ critical salt concentration is injurious to all crops.

(a) 500 ppm

(b) 1000 ppm

(d) 2000 ppm

ANS- D

12. When electrical conductivity of irrigation water is up to ______ micro mhos/cm, it is called low

conductivity water

(a) 125

(b) 250

(d) 500

ANS- B

13. When Sodium-Absorption Ratio (SAR) is 30, it is called

(a) low sodium water

(b) medium sodium water

(d) very high sodium water

ANS- D

14. Even for the most tolerant crop, the boron concentration should not exceed

(a) 4 ppm

(b) 8 ppm

(d) 16 ppm

ANS- A

15. If wheat requires about 75 mm of water after every 28 days, and the base period for wheat is 140

days, the value of delta for wheat is

(a) 2100 mm

(b) 375 mm

(d) none of the above

ANS- B

16. Among the following, which crop has the highest value to delta?

(a) wheat

(b) vegetables

(d) cotton

ANS- C

17. The canal that finally feeds field is known as

(a) minor canal

(b) field channel

(d) branch canal

ANS- B

18. In a canal system the order in which water flows is

(a) branch canal–distributary–minor–field channels

(b) branch canal minor–distributary–field channels

(d) branch canal–field canal–distributary–minor

ANS- A

19. In a channel bed made of fine sand, when the velocity is gradually increased the sequence of bed

formation is:

(a) flat surface dunes–saw tooth ripples–antidunes

(b) saw tooth ripples–dunes–flat surface–antidunes

(d) saw tooth ripples–flat surface–antidunes–dunes

ANS- B

20. Kennedy gave a relation between

(a) area and velocity

(b) critical velocity and depth of flowing water

(d) rainfall and runoff

ANS-B

21. The relation between critical velocity Vo and depth of flowing water y given by Kennedy is

(a) Vo = 0.55 m y

0.64

(b) 0.64 m y

0.55

(d) Vo = 0.55 y m0.7

where m = critical velocity ratio in m

ANS- A

22. For sands greater than the standard, the critical velocity ratio is ______ one.

(a) less than

(b) equal

(d) equal or more than

ANS- D

23. A channel is said to be in regime when

(a) silt grade and silt charge are constant

(b) discharge is constant

(d) all the above

ANS- D

24. According to Lacey

(a) natural silt transporting channels have a tendency to assume a semi-elliptic section

(b) finer the silt, channel closely approximates a semi-circle.

(d) all of these

ANS- D

26. According to Lacey’s silt theory, perimeter P of a channel is proportional to

(a) Q2/5

(b) Q1/2

(d) Q

where Q is discharge

ANS- B

27. Lacey gave a relation between

(a) area and velocity

(b) velocity and hydraulic mean

(d) none of these

ANS- C

28. Lacey assumed that silt is kept in suspension because of the normal components of eddies

generated from

(a) sides only

(b) bed only

(d) none of these

ANS- C

29. Lacey’s general regime equation is

(a) V = 10.8 R

1/3 S

2/3

(b) V = 10.8 R

1/2 S

1/3

2/3 S

1/3

(d) V = 10.8 R

1/2 S

2/3

where V = mean regime velocity

R = hydraulic mean depth

S = slope of water surface

ANS- C

30. According to Lacey’s equation normal regime scour depth R¢ is

(a) 0.473 (Q/f)

1/2

(b) 0.473 (Q/f)

1/3

1/4

(d) 0.473 (Q/f)

1/5

ANS- B

31. A typical and most desirable section of a canal is

(a) in cutting

(b) in filling

(d) none of the above

ANS- C

32. The berms in canal serve

(a) as a good lining for reducing losses

(b) help to attain regime conditions

(d) all of them

ANS- D

33. Assumed value of saturation gradient (H : V) in clay is

(a) 1 : 3

(b) 1 : 4

(d) 1 : 8

ANS- B

34. By adopting lining canals in new projects

(a) earthwork can be reduced

(b) number of canal structures can be reduced

(d) all the above

ANS- D

35. The corners of trapezoidal canal sections are rounded

(a) to increase A/P ratio

(b) depth is limited

(d) none of the above

ANS- C

36. If cement concrete lining is provided to canal, maximum permissible velocity is

(a) 1.5 to 1.8 m/sec

(b) 2 to 2.5 m/sec

(d) 4.0 to 5.0 m/sec

ANS- D

37. As per I.S. code requirement of free board for main canal is

(a) 0.75 m

(b) 1.0 m

(d) 1.5 m

ANS- A

38. As per I.S. recommendations, for a canal with discharge of more than 30 cumecs minimum width

of inspection bank is

(a) 5.0 m

(b) 6.0 m

(d) 10.0 m

ANS- C

39. Which one of the following is wrong about cement concrete tile lining of canals?

(a) Rigid quality control is required.

(b) Expansion joints are not required.

(d) Damaged portion can be repaired easily.

ANS- A

40. Which one of the following is wrong statement about boulder lining of canals?

(a) It helps in retaining the shape of canal section.

(b) It prevents seepage of canal water.

(d) Blasted rock pieces with sufficient base area are ideal for such works.

ANS- B

41. Thickness of stone lining to be adopted for a canal of capacity less than 50 cumecs is

(a) 80 mm

(b) 120 mm

(d) 200 mm

ANS- C

42. Generally, pressure relief valves open out, as soon as the differential pressure become

(a) 100 mm

(b) 200 mm

(d) 500 mm

ANS- A

43. The diameter of pressure relief valves used in the bed and sides of canal are ______respectively.

(a) 50 mm and 150 mm

(b) 100 mm and 200 mm

(d) 200 mm and 100 mm

ANS- C

44. To safeguard the lining material of canals in black cotton soil a thickness of ______ of non-

cohesive soil is required if the swelling pressure is upto 350 to 500 kN/m2

(a) 750 to 850 mm

(b) 900 to 1000 mm

(d) 1400 – 1500 mm

ANS- C

45. In a canal safety ladders are provided on both banks, alternately at about ______ staggered

distance, in straight reaches

(a) 150 m

(b) 300 m

(d) 600 m

ANS- B

46. A land is said to be waterlogged when

(a) it is submerged in flood

(b) the air circulation is stopped in the root zone due to rise in water table

(d) all of these

ANS- B

47. The infertility of the soil in waterlogged area is due to

(a) death of bacteria causing nutrification

(b) increase in salinity

(d) all of the above

ANS- D

48. Waterlogging is due to

(a) overirrigation

(b) impervious obstruction

(d) all of these

ANS- D

49. To avoid formation of saline soil, water table should be kept at least ______ below root zone.

(a) 1 m

(b) 2 m

(d) 5 m

ANS- C

50. Tile drains increase crop yield by

(a) removing the free gravity water that is not directly available to the plants

(b) increasing air circulation

(d) all the above

ANS- D

51. Drainage coefficient depends upon

(a) rain fall

(b) type of soil

(d) all the above

ANS- D

52. The recommended value of drainage coefficient is ______ per cent of the average rainfall to be

removed per day.

(a) 0.5 %

(b) 1.0 %

(d) 2.5 %

ANS- B

53. Which one of the following is not layout of tile drains?

(a) French drain system

(b) Grid iron system

(d) Intercepting drain system

ANS- A

54. In tube well irrigation system the best method of pricing is

(a) flat rate pricing

(b) crop rate system

(d) any of the above

ANS- C

55. The basic factor which controls the process of meandering is

(a) discharge

(b) bed and side resistance

(d) all of these

ANS- D

56. A diversion head work is to

(a) reduce fluctuations in the supply level of the water

(b) raise water level of the head of the canal

(d) all of these

ANS- D

57. A weir is generally aligned at right angles to the direction of river flow, because

(a) it is economical

(b) it needs less length of weir

(d) all the above

ANS- D

58. A solid construction across a river to raise its water level and divert the water into the canal is

known as

(a) bund

(b) barrage

(d) dam

ANS- C

59. Okhla weir on Yamuna river, in Delhi, is an example of

(a) masonry weir

(b) rock fill weir

(d) none of the above

ANS- B

60. Normally difference between the crest level of the under-sluices and the crest level of the weir is

(a) 1 to 1.5 m

(b) 2 to 3.0 m

(d) more than 5 m

ANS- A

61. The function of a scouring sluice is to

(a) control the silt entry into the canal

(b) pass the low floods without dropping the shutters of the main weir

(d) all the above

ANS- D

62. A fish ladder is

(a) a ladder provided in the canal for the maintenance of canal

(b) a ladder to climb up dam

(d) none of the above

ANS- C

63. The canal head regulator

(a) regulates the supply of water entering the canal

(b) controls the entry of silt in the canal

(d) all the above

ANS- D

65. A hydraulic jump is formed when

(a) the two flows of supercritical velocities meet each other

(b) the two flows of subcritical velocities meet each other

(d) a subcritical flow strikes against a supercritical flow

ANS- C

67. According to Bligh’s creep theory, the percolating water follows:

(a) the outline of the base of the foundation

(b) in a straight line path under the floor

(d) none of the above

ANS- A

68. Which one of the following is the wrong statement about Bligh’s creep theory?

(a) Percolating water follows the outline of the base of foundation.

(b) It makes no distinction between horizontal and vertical creeps.

(d) On upstream side floor thickness should be designed carefully.

ANS- D

69. The suggested weightage factor for horizontal to vertical creep by lane is

(a) 1/2

(b) 1/3

(d) 3

ANS- B

70. The loss of head per unit length of creep is called

(a) coefficient of creep

(b) Bligh’s coefficient

(d) percolation coefficient

ANS- D

71. According to Khosla’s theory, the undermining of the floor starts from

(a) starting end

(b) intermediate point

(d) tail end

ANS- D

72. According to Khosla’s theory, the first streamline follows bottom contour of the structure and the

remaining streamlines follow smooth curves, transmitting slowly from the outline of foundation to

a ______.

(a) circular curve

(b) catenary curve

(d) parabolic curve

ANS- C

73. A parabolic glacis type of fall is known as

(a) Sarda fall

(b) Inglis fall

(d) Ogee fall

ANS- C

74. The type of fall which consists of an inlet well with a pipe at its bottom to carry water to a

downstream well is known as

(a) cylindrical fall

(b) pipe fall

(d) straight glacis fall

ANS- A

75. The fall consisting of convex and concave curves is known as

(a) Moutague type fall

(b) Inglis fall

(d) Ogee fall

ANS- D

76. The fall that is suitable for high drops with low discharge is

(a) baffle type

(b) straight glacis

(d) vertical drop type

ANS- C

77. ______ fall can be used for all discharges when drop is more than 1.5 m.

(a) Baffle type

(b) Straight glacis

(d) Vertical drop type

ANS- A

78. The canal fall which is quite satisfactory but becomes obsolete due to high cost is

(a) Ogee fall

(b) rapids

(d) well type fall

ANS- B

79. Which of the following statement is wrong?

(a) Ogee fall consists of convex and concave curves.

(b) Rapids worked out quite satisfactory but were expensive.

remains practically unaffected.

(d) Simple vertical drop type falls are known as well type falls.

ANS- D

80. Which one of the following is the wrong statement about a head regulator?

(a) When the water level in main channel is low, it helps in heading up water.

(b) Controls the supplies entering the off-take channel.

(d) Serves as a meter for measuring discharge.

ANS- A

81. Hand operated gates of cross regulators can have spans of

(a) 2 – 3 m

(b) 4 – 5 m

(d) 9 – 12 m

ANS- C

82. The crest level of the distributary head is generally kept at ______ higher than the bed level of the

parent channel.

(a) 0.3 to 1.0 m

(b) 1.2 – 1.8 m

(d) more than 2.5 m

ANS- A

83. The minimum capacity of the escape channel is kept as ______ of the channel capacity.

(a) 1/4

(b) 1/3

(d) 2/3

ANS-

84. The outlet through which the discharge depends upon the difference of head between the

distributary and the water-course, is known as

(a) non-modular outlet

(b) modular outlet

(d) rigid module

ANS- A

85. In a flexible module, the discharge depends upon

(a) water level of the water-course

(b) water level of the distributary

(d) none of the above

ANS- B

86. In Gib’s module, the discharge

(a) depends upon water level of the water-course only

(b) depends upon water level of the distributary only

(d) is independent of all above

ANS- D

87. The ratio of the rate of change of discharge of the outlet to the rate of change of discharge of the

distributary channel is known as

(a) flexibility

(b) proportionality

(d) setting

ANS- A

88. An outlet is said to be proportional when the ratio of the rate of change of outlet discharge to the

rate of channel discharge is

(a) less than unity

(b) equal to unity

(d) any constant

ANS- B

89. For rigid modules sensitivity is

(a) zero

(b) less than unity

(d) more than unity

ANS- B

90. A pipe or orifice type outlet is proportional, if the outlet is fixed at ______ times the depth below

the water surface.

(a) 0.3

(b) 0.4

(d) 0.6

ANS- A

91. For the weir type outlet to be proportional, the outlet should be set at ______ times the depth

below the water surface.

(a) 0.3

(b) 0.5

(d) 0.9

ANS- D

92. The ratio of the rate of change of discharge through the outlet to the rate of change of water level

of the distributary, referred to the normal depth of the channel, is known as

(a) setting

(b) sensitivity

(d) drowning ratio

ANS- B

93. The ratio of the depth of water level over crest on the downstream of the module to the depth of

water level over crest on the upstream of module is known as

(a) setting

(b) sensitivity

(d) drowning ratio

ANS- D

94. Which of the following is a non-modular outlet?

(a) Pipe outlet

(b) Submerged pipe outlet

(d) Open flume

ANS- B

95. Which of the following is a type of semi-module outlet?

(a) Submerged pipe outlet.

(b) Open sluice.

(d) Gibb’s module.

ANS-C

96. Which one of the following statements is about a syphon aqueduct?

(a) The drain bed is depressed and provided with pucca floor.

(b) The drainage bed is joined to pucca floor by a vertical drop.

(d) HFLof the drain is sufficiently below the bottom of the canal.

ANS- D

97. The cross drainage work in which the drain is taken over the canal such that the canal water runs

below the drain freely is known as

(a) aqueduct

(b) syphon aqueduct

(d) canal syphon

ANS-C

98. Which one of the following statement is wrong?

(a) An inlet is a structure constructed in order to allow the drainage water to enter canal.

(b) Inlets are constructed when the drainage discharge is small and the drain crosses the canal with

its bed level is equal to or slightly higher.

(d) The number of inlets and outlets should always be same.

ANS-D

99. By greater fluming the canal

1. width of aqueduct is reduced.

2. the length of transition wings is increased

(a) both 1 and 2 are correct

(b) 1 is correct but 2 is wrong

(d) both 1 and 2 are wrong

ANS-A

100. The depth of water stored in an irrigation tank, rarely exceeds

(a) 4 m

(b) 8 m

(d) 16 m

ANS-C

101. The storage created by construction of low earthern bunds, is known as

(a) a reservoir

(b) a lake

(d) none of these

ANS-C

102. The provision of suitable breaching sections becomes more important in irrigation tanks, which

are

(a) in groups

(b) isolated

(d) none of them

ANS-A

103. The capacity of an irrigation tank is sometimes increased by installing

(a) dam stones

(b) breast well

(d) saddle

ANS- A

104. A minor irrigation scheme involves command area equal to or less than

(a) 500 hectares

(b) 1000 hectares

(d) 3000 hectares

ANS-C

105. The discharge through the sluice of a small irrigation tank is usually controlled by

(a) dam stone

(b) shutter gate

(d) all of these

ANS- C

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Objective of civil engineering irrigation engineering

Objective of civil engineering irrigation engineering

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