About Irrigation Engineering

Following are some of the multiple choice questions on the Irrigation Engineering with answers that will help the students in developing their knowledge.

Irrigation Engineering MCQ

1. Seepage through embankments in an earthen dam is controlled by

  • drainage filters
  • relief wells
  • drain trenches
  • provision of downstream berms

2. Unit of runoff in M.K.S. system is

  • cubic metre/sec
  • metre/sec
  • cubic metre
  • square metre

3. Borrow pits should preferably be located in

  • Field on the left side of the canal
  • Field on the right side of the canal
  • Fields on both sides of the canal
  • Central half width of the section of the canal

4. The flow of water after spilling over the weir crest in chute spillway and side channel spillway respectively are

  • At right angle and parallel to weir crest
  • Parallel and at right angle to weir crest
  • Parallel to weir crest in both
  • At right angle to weir crest in both

5. The depth of water required to bring the soil moisture content of a given soil upto its field capacity is called

  • hygroscopic water
  • equivalent moisture
  • soil moisture deficiency
  • pellicular water

6. For an annual flood series arranged in descending order of magnitude, the return for a magnitude listed at position period m in a total data N is

  • N/(m+l)
  • m/(N+l)
  • m/N
  • (N+l)/m

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

  • Maximum saturated point
  • Permanent wilting point
  • Ultimate utilization point
  • None of these

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

  • Field capacity
  • Saturation capacity
  • Moisture content at permanent wilting point
  • Difference between filed capacity and permanent wilting point within the root zone of plants

9. As compared to gravity dams, earthen dams

  • are costlier
  • are less susceptible to failure
  • require sound rock foundations
  • require less skilled labour

10. The ratio of rate of change of the discharge of an outlet to the rate of change of the discharge of distributing channel is called

  • proportionality
  • flexibility
  • setting
  • sensitivity

11. Pick up the incorrect statement from the following. Culturable commanded area is the gross area of an irrigation canal system less

  • Populated area
  • Alkaline area
  • Forest area
  • Fallow land

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

  • D = Δ (8.64 D/B)
  • B = Δ (8.64 B/D)
  • D = (8.6 Δ/B)
  • Δ = (8.6 B/D)

13. Which of the following types of rain gauges is used for measuring rain in remote hilly inaccessible areas ?

  • tipping bucket type
  • weighing type
  • floating type
  • Simon’s raingauge

14. In gravity canals, F.S.L. is

  • Always at the ground level
  • Always below the ground level
  • Generally 4 to 5 meters above the ground level
  • Only a few cm above the ground level

15. Which of the following can be used as a meter fall ?

  • vertical drop fall
  • flumed glacis fall
  • unflumed glacis fall
  • all of the above

16. The value of Sodium Absorption Ratio for high sodium water lies between

  • 0 to 10
  • 10 to 18
  • 18 to 26
  • 26 to 34

17. 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

  • Q = 1.71 BD1/2
  • Q = 1.71 BD
  • Q = 1.71 BD3/2
  • Q = 1/71 BD2/3

18. If d is the depth of the aquifer through which water is flowing, then the relationship between permeability k and transmissible T is given by

  • T = kd
  • T = k/d
  • T= Vkd
  • k= VTd

19. Bed bars in a canal are provided

  • To watch the general behavior of canal
  • To measure the discharge
  • To raise the supply level
  • To control the silting

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

  • Ground slope exceeds the designed bed slope
  • Designed bed slope exceeds the ground slope
  • Ground slope is practically the same as the designed bed slope
  • None of these

21. The ratio of the discharge over a trapezoidal crest to a rectangular crest of Sarda falls of identical parameters, is

  • 1.084
  • 1.074
  • 1.064
  • 1.054

22. In a syphon aqueduct

  • Drainage passes over the canal and F.S.L. of the canal is below the bottom of the drainage trough
  • Drainage passes over the canal and F.S.L. of the canal is above the bottom of the drainage trough
  • Canal passes over the drainage and H.F.L. of the drainage is above the bottom of the canal trough
  • Canal passes over the drainage and H.F.L. of the drainage is below the bottom of the canal trough

23. Which of the following canal structures is used to remove surplus water from an irrigation channel into a natural drain ?

  • canal fall
  • canal outlet
  • canal escape
  • canal regulator

24. The sensitivity of a rigid module is

  • zero
  • between zero and one
  • 1
  • infinity

25. The width of a dowla is generally kept between 30 to 60 cm and its height above the road level should invariably be more than

  • 10 cm
  • 20 cm
  • 30 cm
  • 40 cm

26. The most suitable section of a lined canal, is

  • Triangular section with circular bottom for small canals
  • Trapezoidal section with rounded corners for large canals
  • Both (A) and (B)
  • None of these

27. A deep well

  • is always deeper than a shallow well
  • has more discharge than a shallow well
  • is weaker structurally than a shallow well
  • both (A) and (B)

28. The uplift pressure on the face of a drainage gallery in a dam is taken as

  • hydrostatic pressure at toe
  • average of hydrostatic pressure at toe and heel
  • two-third of hydrostatic pressure at toe plus one-third of hydrostatic pressure at heel
  • none of the above

29. A counter berm is

  • A horizontal benching provided on the inside slope
  • A horizontal benching provided on the outside slope
  • A vertical benching provided on the outer edge of the bank
  • A vertical benching provided on the inner edge of the bank

30. Wetted perimeter of a regime channel for a discharge of 64 cumecs as per Lacey’s theory will be

  • 19m
  • 38m
  • 57m
  • 76m

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

  • Square root of the discharge
  • Discharge
  • Square of the discharge
  • Cube of the discharge

32. The water face of the guide banks, is protected by

  • One men stone pitching
  • Two man stone pitching
  • Three man stone pitching
  • Four man stone pitching

33. The uplift pressure on the roof of an inverted syphon, is maximum when

  • Drain in running dry
  • Canal is running dry
  • Canal is running with F.S.L.
  • Drain is running with H.F.L.

34. The ratio of the average load to the installed capacity of the plant whose reserve capacity is zero will be equal to

  • Load factor
  • Plant factor
  • Utilization factor
  • Both (A) and (B)

35. The length of a meander is the distance along the river between the tangent point of one curve to the tangent point of

  • Reverse curve
  • Next curve of the same order
  • Reverse curve plus the width of the river
  • None of these

36. The consumptive use of water for a crop

  • Is measured as the volume of water per unit area
  • Is measured as depth of water on irrigated area
  • May be supplied partly by precipitation and partly by irrigation
  • All the above

37. A divide wall is provided

  • At right angle to the axis of weir
  • Parallel to the axis of weir and upstream of it
  • Parallel to the axis of weir and downstream of it
  • At an inclination to the axis of weir

38. A 6 hours storm had 4 cm of rainfall and the resulting runoff was 2 cm. If ϕ index remains at the same value, the runoff due to 10 cm of rainfall in 12 hours in the catchment is

  • 4.5 cm
  • 6.0 cm
  • 7.5 cm
  • 9.0 cm

39. A multipurpose reservoir is the one which is

  • designed for one purpose but serves more than one purpose
  • planned and constructed to serve various purposes
  • both (A) and (B)
  • none of the above

40. V and R are the regime mean velocity and hydraulic mean depth respectively in meters. Lacey's silt factor f is

  • 2V²/√3 R
  • 3V²/4R
  • 5V²/2R
  • 2V²/5R

41. Useful soil moisture for plant growth, is

  • Capillary water
  • Gravity water
  • Hygroscopic water
  • Chemical water

42. A 70% index of wetness means

  • rain excess of 30%
  • rain deficiency of 30%
  • rain deficiency of 70%
  • none of the above

43. According to Kennedy, the critical velocity (V₀) in meters in a channel is the mean velocity which keeps the channel free from silting or scouring. Its value is given by (where m is critical velocity ratio and D is the depth of the channel).

  • V₀ = 0.84 mD0.64
  • V₀ = 0.55 mD0.64
  • V₀ = 0.84 mD0.54
  • V₀ = 0.55 mD0.54

44. The main cause of meandering is

  • presence of an excessive bed slope in the river
  • degradation
  • the extra turbulence generated by the excess of river sediment during floods
  • none of the above

45. Under the same conditions, which of the following shapes of water surface will give the highest rate of evaporation ?

  • flat water surface
  • convex water surface
  • concave water surface
  • independent of shape of water surface

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

  • D = 0.47 (Q/f)
  • D = 0.47 (Q/f)1/2
  • D = 0.47 (Q/f)1/3
  • D = 0.47 (Q/f)2/3

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

  • Its breadth must only be known
  • Its depth must only be known
  • Its breadth and depth ratio must only be known
  • All the above

48. An artesian aquifer is the one where

  • water surface under the ground is at atmospheric pressure
  • water is under pressure between two impervious strata
  • water table serves as upper surface of zone of saturation
  • none of the above

49. A river is said to be of

  • Aggrading type if it builds up its bed to a certain slope
  • Degrading type if it cuts its bed to a certain slope
  • Meandering type if it flows in sinuous curve
  • All the above

50. Trap efficiency of a reservoir is a function of

  • capacity/inflow ratio
  • capacity/outflow ratio
  • outflow/inflow ratio
  • none of the above

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