Civil Engineering - Irrigation MCQs Part 2

1. A deficit of sediments in flowing water may cause a river

A.
meandering type

B.
aggrading type

C.
degrading type

D.
sub-critical type.

 Answer Option C

2. Pick up the correct statement from the following:

A.
The full supply level of a canal should be above ground level

B.
According to Lacey, regime conditions require a particular slope for a given discharge and silt factor

C.
In case the ground slope is less than the required bed slope, the silt factor must be reduced by permitting the entry of coarse silt

D.
All the above.

 Answer Option D

3. If Δ is the depth of water in metres, B is the number of days of base period and D is the duty in hactare/cumec, the relationship which holds good, is

A.

B.

C.

D.

E.
none of these.

 Answer Option D

4. Meandering of a river generally occurs, in

A.
rocky stage

B.
delta stage

C.
boulder stage

D.
trough stage.

 Answer Option D

5. The consumptive use of water for a crop

A.
is measured as the volume of water per unit area

B.
is measured as depth of water on irrigated area

C.
may be supplied partly by precipitation and partly by irrigation

D.
all the above.

 Answer Option D

6. The velocity of drainage water in the barrels of a syphon-aqueduct, is normally limited to

A. 1 to 2 m per second

B. 2 to 3 m per second

C. 3 to 4 m per second

D. 4 to 5 m per second.

 Answer Option B

7. A fall in a canal bed is generally provided, if

A. ground slope exceeds the designed bed slope

B. designed bed slope exceeds the ground slope

C. ground slope is practically the same as the designed bed slope

D. none of these.

 Answer Option A

8. According to Khosla, the exist gradient of surface flow

A. depends upon the b/d ratio

B. is independent of the b/d ratio

C. is independent of the depths of d/s cut off walls

D. none of these.

 Answer Option A

9. Pick up the correct statement from the following:

A. Gravity water is harmful to crops

B. Hygroscopic water remains attached to soil molecules by chemical bond

C. Capillary moisture held in the soil pores against gravity by surface tension, is utilised by plants

D. All the above.

 Answer Option C

10. If the irrigation efficiency is 80%, conveyance losses are 20% and the actual depth of watering is 16 cm, the depth of water required at the canal outlet, is

A. 10 cm

B. 15 cm

C. 20 cm

D. 25 cm

E. 30 cm

 Answer Option D

11. The scour depth D of a river during flood, may be calculated from the Lacey's equation

A.

B.

C.

D.

 Answer Option C

12. If V0 is the critical velocity of a channel, its silt transporting power, according to Kennedy, is proportional to

A.

B.

C.

D.

E.

 Answer Option C

13. The useful moisture of soil, is equal to its

A. field capacity

B. saturation capacity

C. moisture content at permanent wilting point

D. difference between filed capacity and permanent wilting point within the root zone of plants.

 Answer Option D

14. Canals taken off from ice-fed perennial rivers, are known

A. permanent canals

B. ridge canals

C. perennial canals

D. inundation canals

E. ice canals.

 Answer Option C

15. The down stream expansion head of a guide bank is extended to subtend an angle at the centre, equal to

A. 30°

B. 45°

C. 60°

D. 90°

 Answer Option B

16. Trial procedure of canal design by Kennedy's theory is based upon the equation

A. Q = A . Y

B.

C.

D. all the above.

 Answer Option D

17. The main cause of silting up a channel,

A. non-regime section

B. inadequate slope

C. defective head regulator

D. defective outlets

E. all the above.

 Answer Option E

18. In north Indian Plains, optimum depth of kor watering for wheat, is

A. 23.0 cm

B. 19.0 cm

C. 17.5 cm

D. 13.5 cm

E. 12.0 cm

 Answer Option D

19. Bed bars in a canal are provided

A. to watch the general behaviour of canal

B. to measure the discharge

C. to raise the supply level

D. to control the silting

E. all the above.

 Answer Option A

20. The most suitable location of a canal head work, is

A. boulders stage of the river

B. delta stage of the river

C. rock stage of the river

D. trough stage of the river.

 Answer Option D

21. Useful soil moisture for plant growth, is

A. capillary water

B. gravity water

C. hygroscopic water

D. chemical water

E. all the above.

 Answer Option A

22. A hydraulic structure is designed to withstand

A. seepage forces

B. hydraulic jump

C. hydraulic pressure

D. all the above.

 Answer Option D

23. In gravity canals, F.S.L. is

A. always at the ground level

B. always below the ground level

C. generally 4 to 5 metres above the ground level

D. only a few cm above the ground level.

 Answer Option D

24. If d1 is the depth of cutting, d2 is the height of the bank from bed level r2 : 1 and r1 : 1 are the slopes in filling and cutting respectively, the horizontal distance n between the bed and bank, is

A. x = r1 d1

B. x = r2 d2

C. x = d1 / r1

D. x = d2 / r2

 Answer Option B

25. The structure constructed to allow drainage water to flow under pressure through an inverted syphon below a canal, is called

A. syphon

B. super passage

C. aqueduct

D. super-aqueduct

E. syphon aqueduct.

 Answer Option E

26. The optimum depth of kor watering for a rice crop, is

A. 23.0 cm

B. 19.0 cm

C. 17.5 cm

D. 13.5 cm

E. 12.0 cm

 Answer Option B

27. Bligh's theory of seepage assumes

A. equal weightage to the horizontal and vertical creep

B. more weightage to horizontal creep than vertical creep

C. less weightage to horizontal creep than vertical creep

D. loss of head follows the sine curve.

 Answer Option A

28. The Lacey's regime velocity is proportional to

A. R1/2 S3/4

B. Q3/4 S1/3

C. R3/4 S1/3

D. R2/3 S1/2

 Answer Option C

29. A hydraulic jump is generally formed when a stream moving with

A. a hyper-critical velocity meets a stream moving with a critical velocity

B. a hyper-critical velocity meets a stream moving with a hyper-critical velocity

C. A hyper-critical velocity meets a stream moving with a sub-critical velocity

D. a sub-critical velocity meets a stream moving with a hyper-critical velocity.

 Answer Option C

30. For a unique design of a channel by Kennedy's theory

A. its breadth must only be known

B. its depth must only be known

C. its breadth and depth ratio must only be known

D. all the above.

 Answer Option C

31. In a barrage, the crest level is kept

A. low with large gates

B. high with large gates

C. high with no gates

D. low with no gates.

 Answer Option A

32. For a standing crop, the consumptive use of water is equal to the depth of water

A. transpired by the crop

B. evaporated by the crop

C. transpired and evaporated by the crop

D. used by the crop in transpiration, evaporation and also the quantity of water evaporated from adjacent soil.

 Answer Option D

33. The state of the soil when plants fail to extract sufficient water for their requirements, is

A. maximum saturated point

B. permanent wilting point

C. ultimate utilisation point

D. none of these.

 Answer Option B

34. The field capacity of a soil is 25%, its permanent wilting point is 15% and specific dry unity weight is 1.5. If the depth of root zone of a crop, is 80 cm, the storage capacity of the soil, is

A. 8 cm

B. 10 cm

C. 12 cm

D. 14 cm

E. 16 cm

 Answer Option C

35. Solution of Laplacian equation in three dimensions of water in a syphon, is done by

A. analytical method

B. Khosla's method

C. method of relaxation

D. Unwin's method.

 Answer Option C

36. The length and width of a meander and also the width of the river, vary roughly as

A. square root of the discharge

B. discharge

C. square of the discharge

D. cube of the discharge.

 Answer Option A

37. Regime conditions in a channel may occur if

A. discharge is constant

B. channel flows uniformly in incoherent alluvium as that transported in suspension

C. silt grade and silt charge are constant

D. all the above.

 Answer Option D

38. If the optimum depth of kor watering for a crop is 15.12 cm, the outlet factor for the crop for four week period in hectares per cumec, is

A. 1000

B. 1200

C. 1400

D. 1600

E. 2000

 Answer Option D

39. If H and d are the water depth and drop in the bed level at a Sarda fall, the width B of the trapezoidal crest, is given by

A. B = 0.22 H + d

B. B = 0.33 H + d

C. B = 0.44 H + d

D. B = 0.55 H + d

 Answer Option D

40. According to Bligh's creep theory, percolating water flows along

A. straight path under the foundation of the dam

B. circular path under the foundation of the dam

C. the outline of the base of the foundation of the dam

D. none of these.

 Answer Option C

41. The width of a meander belt is the transverse distance between

A. apex point of one curve and apex point of the reserve curve

B. apex point and the crossing

C. two banks of meandering river

D. none of these.

 Answer Option A

42. The sensitivity of a rigid module, is

A. 2.00

B. 1.50

C. 1.00

D. 0.50

E. zero

 Answer Option E

43. An outlet which maintains a constant discharge irrespective of fluctuation in the water levels of the supplying channel or water course, is known as

A. non-modular outlet

B. semi-modular outlet

C. flexible modular outlet

D. right modular outlet.

 Answer Option D

44. Canals constructed for draining off water from water logged areas, are known

A. drains

B. inundation canals

C. valley canals

D. contour canals

E. ridge canals.

 Answer Option A

45. A minimum of 90 cm free board is provided if the discharge in the canal is between

A. 30 to 33 cumecs

B. 30 to 60 cumecs

C. Over 60 cumecs

D. Over 100 cumecs

 Answer Option C

46. If D is the depth of water upstream of the throat above its sill, B is the width of the throat, to achieve critical flow in an open venturi flume, the theoretical maximum flow Q, is

A. Q = 1.71 BD1/2

B. Q = 1.71 BD

C. Q = 1.71 BD3/2

D. Q = 1/71 BD2/3

E. none of these.

 Answer Option C

47. If straight sides of a triangular section of a lined canal with circular bottom of radius R, make an angle θ with horizontal, the area of its cross-section, is

A. R(θ + tan θ)

B. R(θ + cot θ)

C. R2(θ + tan θ)

D. R2(θ + cot θ)

E. R(θ + tan θ)

 Answer Option D

48. Lacy's regime condition is obtained if

A. silt grade in the channel is variable

B. discharge in the channel is variable

C. silt charge in the channel is variable

D. channel flows in unlimited, incoherent alluvium of the same character as that transported material.

 Answer Option D

49. In Montague type fall

A. a straight glacis is provided

B. a circular glacis is provided

C. a parabolic glacis is provided

D. no glacis is provided.

 Answer Option C