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. 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

2. 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

3. The sensitivity of a rigid module is

  • zero
  • between zero and one
  • 1
  • infinity

4. 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

5. 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

6. 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)

7. 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

8. 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

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

  • 19m
  • 38m
  • 57m
  • 76m

10. 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

11. 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

12. 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.

13. 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

14. 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)

15. 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

16. 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

17. 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

18. 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

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

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

20. 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

21. 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)

22. 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

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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

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

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

30. 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

31. 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

32. As compared to gravity dams, earthen dams

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

33. 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

34. 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

35. 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

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

  • Syphon
  • Super passage
  • Super-aqueduct
  • Syphon aqueduct

37. The amount of irrigation water required to meet the evapotranspiration needs of the crop during its full growth is called

  • effective rainfall
  • consumptive use
  • consumptive irrigation requirement
  • net irrigation requirement

38. The main function of a diversion head works of a canal from a river, is

  • To remove silt
  • To control floods
  • To store water
  • To raise water level

39. The kor depth for rice is 190 mm and kor period is 14 days. The outlet factor for this will be

  • 637 hectares/m3/sec
  • 837 hectares/m3/sec
  • 972 hectares/m3/sec
  • 1172 hectares/m3/sec

40. The ratio of average values of shear stresses produced on the bed and the banks of a channel due to flowing water is

  • less than 1
  • equal to 1
  • greater than 1
  • equal to zero

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

  • Apex point of one curve and apex point of the reserve curve
  • Apex point and the crossing
  • Two banks of meandering river
  • None of these

42. If the risk of a flood occurring in the next 10 years is accepted to 10%, then the return period for design should be

  • 1 + (0.9)010
  • 1 – (0.9)°l0
  • 1/(1-0.9°10)
  • 1/(1+ 0.9010)

43. The uplift pressure on a dam can be controlled byi) constructing cutoff under upstream faceii) constructing drainage channels bet-ween the dam and its foundationiii) by pressure grouting in foundationThe corret answer is

  • only (i)
  • both (i) and (ii)
  • both (i) and (iii)
  • (i), (ii) and (iii)

44. The downstream expansion head of a guide bank is extended to subtend an angle at the centre, equal to

  • 30°
  • 45°
  • 60°
  • 90°

45. For wave action in dams, the maximum height of freeboard is generally taken to be equal to (where hw is height of wave.)

  • 0.5 hw
  • 0.75 hw
  • 1.25 hw
  • 1.50 hw

46. The difference in level between the top of a bank and supply level in a canal, is called

  • Berm
  • Free board
  • Height of bank
  • None of these

47. 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

  • 10 cm
  • 15 cm
  • 20 cm
  • 25 cm

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

  • 30 to 33 cumecs
  • 30 to 60 cumecs
  • Over 60 cumecs
  • Over 100 cumecs

49. 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

  • x = r1 d1
  • x = r2 d2
  • x = d1 / r1
  • x = d2 / r2

50. Irrigation water having the concentration of Na++ , Ca++ and Mg++ as 20, 3 and 1 Milli equivalent per litre respectively will be classified as

  • low sodium water
  • medium sodium water
  • high sodium water
  • very high sodium water

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