Irrigation Engineering MCQ Questions & Answers | Civil Engineering
part - 3
41) For the design of major hydraulic structures on the canals, the method generally preferred to, is based on
(A) Bligh's theory
(B) Electrical analogy method
(C) The relaxation method
(D) Khosla's method of independent variables
Answer: Option D (
42) Pick up the incorrect statement from the following:-
(A) In free flooding irrigation, water is admitted at one corner of a field and is allowed to spread over the entire area
(B) In check method of irrigation, the field is divided into smaller compartments and water is admitted to each in turn
(C) In furrow irrigation water is admitted between the rows of plants in the field
(D) None of these
Answer: Option D (
43) Pick up the incorrect statement from the following
(A) Side walls of a venturi head flume are splayed out from the end of the throat at 1 : 10 for a length of 4.5 m
(B) Length of side walls should be such that the width of the flume is made equal to 2/3rd the bed width of the distributary
(C) Once the width of the flume becomes 2/3rd of the width of the distributary, the splayed walls are increased to 1 in 3 to get full bed width
(D) None of these
Answer:
44) Irrigation canals are generally aligned along
(A) Ridge line
(B) Contour line
(C) Valley line
(D) Straight line
Answer: Option A
45) In a canal syphon, the flow is
(A) Under atmospheric pressure
(B) Pipe flow
(C) With critical velocity
(D) Under negative pressure
Answer: Option B
46
Pick up the correct statement from the following
(A) Approach of the water line in a flumed channel section should not be steeper than 22½°
(B) Departure of the water line from a flumed channel section should not be steeper than 30°
(C) Approach of the water line should not be steeper than 30° and departure line not steeper
than 22½° in a flumed channel section
(D) Approach and departure of the water line in a flumed channel section, should not be steeper
than 22½°
Answer: Option C
47
The main function of a diversion head works of a canal from a river, is
(A) To remove silt
(B) To control floods
(C) To store water
(D) To raise water level
Answer: Option D
48
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
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
(A) x = r1 d1
(B) x = r2 d2
(C) x = d1 / r1
(D) x = d2 / r2
Answer: Option B
50
If V0 is the critical velocity of a channel, its silt transporting power, according to Kennedy, is
proportional to
(A) V01/2
(B) V03/2
(C) V05/2
(D) V07/2
Answer: Option C
51
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
52
A river is said to be of
(A) Aggrading type if it builds up its bed to a certain slope
(B) Degrading type if it cuts its bed to a certain slope
(C) Meandering type if it flows in sinuous curve
(D) All the above
Answer: Option D
53
The ratio of the rate of change of discharge of an outlet and parent channel, is known as
(A) Efficiency
(B) Sensitivity
(C) Flexibility
(D) Modular limit
Answer: Option C
54
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
(A) 10 cm
(B) 20 cm
(C) 30 cm
(D) 40 cm
Answer: Option C
55
Pick up the correct statement from the following:
(A) Water table generally follows the ground surface above it with a few exceptions
(B) Static level of water in an open well indicates the position of the water table
(C) At water table, hydrostatic pressure is zero
(D) All the above
Answer: Option D
56
Lacey's equation for calculating flood discharge in rivers, is
(A) V = 10.8 R1/2 S1/2
(B) V = 10.8 R2/3 S1/2
(C) V = 10.8 R2/3 S1/3
(D) V = 10.8 R1/3 S2/3
Answer: Option C
57
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
58
Side slopes generally kept for canals in loam soil, are:
(A) 1 : 1 in cutting and 1½ : 1 in filling
(B) 1½ : 1 in cutting and 2 : 1 in filling
(C) Neither (a) nor (b)
(D) Both (a) and (b)
Answer: Option D
59
For the stability of a structure against seepage pressure according to Khosla's creep theory, the
critical gradient is
(A) Zero
(B) 0.25
(C) 0.50
(D) 1.00
Answer: Option D
60
If B and d are the bed width and depth of a channel in metres, the combined losses due to
evaporation and seepage in cumecs per kilometre length of the channel, is
(A) (1/50) × (B + d)2/3
(B) (1/100) × (B + d)2/3
(C) (1/150) × (B + d)2/3
(D) (1/200) × (B + d)2/3
Answer: Option D
61
The length of a meander is the distance along the river between the tangent point of one curve to
the tangent point of
(A) Reverse curve
(B) Next curve of the same order
(C) Reverse curve plus the width of the river
(D) None of these
Answer: Option B
62
The top of the capillary zone
(A) Lies below the water table at every point
(B) Lies above the water table at every point
(C) Coincides the water table at every point
(D) None of these
Answer: Option B
63
The depth of rice root zone, is
(A) 50 cm
(B) 60 cm
(C) 80 cm
(D) 90 cm
Answer: Option D
64
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
Answer: Option D
65
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
66
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
67
In case of a trapezoidal notch fall
(A) Top length of the piers should not be less than their thickness
(B) Splay upstream from the notch section is 45°
(C) Splay downstream from the notch section is 22½°
(D) All the above
Answer: Option D
68
Finally formed berms in canals are provided for
(A) Protection of banks erosion by the waves
(B) Control of seepage losses
(C) Strengthening of banks
(D) All the above
Answer: Option D
69
Process of meandering is due to
(A) Sediment load of streams
(B) Discharge and hydraulic properties of streams
(C) Relative erodibility of the bed and banks
(D) All the above
Answer: Option D
70
The ratio of the rate of change of discharge of an outlet to the rate of change in level of water
surface in a distributary at its normal depth, is known as
(A) Efficiency
(B) Sensitivity
(C) Flexibility
(D) Modular limit
Answer: Option B
71
The ratio of the head recovered to the head put in, is known as
(A) Efficiency
(B) Sensitivity
(C) Flexibility
(D) Modular limit
Answer: Option A
72
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
73
The scour depth D of a river during flood, may be calculated from the Lacey's equation
(A) D = 0.47 (Q/f)
(B) D = 0.47 (Q/f)1/2
(C) D = 0.47 (Q/f)1/3
(D) D = 0.47 (Q/f)2/3
Answer: Option C
74
For the conditions enumerated to provide a crossing at C1 You will probably provide
(A) An aqueduct
(B) A super-passage
(C) A syphon aqueduct
(D) None of these
Answer: Option B
75
When a canal and a drainage approach each other at the same level, the structure so provided, is
(A) An aqueduct
(B) A syphon
(C) A level crossing
(D) Inlet and outlet
Answer: Option C
76
The difference in level between the top of a bank and supply level in a canal, is called
(A) Berm
(B) Free board
(C) Height of bank
(D) None of these
Answer: Option B
77
If L is total length of a canal in kilometres, P is total perimeter of its lining in metres and C is the
cost of lining per square metre, the additional expenditure involved on lining, is
(A) 100 PLC
(B) PLC/1000
(C) PL/1000C
(D) PC/100L
Answer: Option A
78
The crest level of a canal diversion head work, depends upon
(A) F.S.L. of the canal
(B) Discharge perimeters
(C) Pond level
(D) All the above
Answer: Option D
79
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
80
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
81
A land is said to be water-logged if its soil pores within
(A) A depth of 40 cm are saturated
(B) A depth of 50 cm are saturated
(C) Root zone of the crops are saturated
(D) All the above
Answer: Option C
82
V and R are the regime mean velocity and hydraulic mean depth respectively in metres. Lacey's
silt factor f is
(A) 2V² R
(B) 3V²/4R
(C) 5V²/2R
(D) 2V²/5R
Answer: Option C
83
A counter berm is
(A) A horizontal benching provided on the inside slope
(B) A horizontal benching provided on the outside slope
(C) A vertical benching provided on the outer edge of the bank
(D) A vertical benching provided on the inner edge of the bank
Answer: Option B
84
While deciding the alignment of a proposed canal taking off from a river at B, three alignments of
approximately equal lengths are available. These cross a drainages at C1, C2and C3 where drainage
bed levels C1 > C2 > C3, you will provide at site C3
(A) An aqueduct
(B) A syphon aqueduct
(C) A super passage
(D) A syphon
Answer: Option A
85
Canals constructed for draining off water from water logged areas, are known
(A) Drains
(B) Inundation canals
(C) Valley canals
(D) Contour canals
Answer: Option A
86
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
87
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
88
If the straight sides of a triangular section of a lined canal with circular bottom of radius R, make
(A) R
(B) 2R
(C) R
(D) 2R
Answer: Option D
89
According to G.W. Pickles the effect of confining the flood water of a river between levee, is to
increase
(A) Rate of flood wave
(B) Water surface elevation during floods
(C) Maximum discharge
(D) Surface slope of streams above the levied portion
Answer: Option D
90
F.S.L. of a canal at its head with respect to parent channel is kept
(A) At the same level
(B) 15 cm lower
(C) 15 cm higher
(D) None of these
Answer: Option B
91
The depth of the crest of a scouring sluice below the crest of a head regulator, is generally kept
(A) 0.20 m
(B) 1.20 m
(C) 2.20 m
(D) 3.20 m
Answer: Option B
92
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
93
If D1 and D2 are depths of water upstream and downstream of a hydraulic jump, the loss of head at
the jump, is
(A) (D - D 3/D D
(B) (D - D 3/2D D
(C) (D - D 3/3D D
(D) (D - D 3/4D D
Answer: Option D
94
Garnett's diagrams are used for graphical solution of design equations of a canal by
(A) Lacey's theory
(B) Kennedy's theory
(C) Gibb's theory
(D) Lindlay theory
Answer: Option B
95
To control the silt entry into a distributary at head regulator, King's vanes are provided which are
the walls
(A) Of R.C.C. or steel plate 8 cm thick
(B) th the depth of water in the main canal
(C) Spaced at interval of 1½ times their heights
(D) All the above
Answer: Option D
96
Effective precipitation for a crop may be defined as
(A) Total precipitation minus the loss due to evaporation
(B) Total precipitation minus the loss due to infiltration
(C) Total precipitation during the crop period
(D) Available water stored in soil within root zone of the crop
Answer: Option D
97
If straight sides of a triangular section of a lined canal with circular bottom of radius R, make an
-section, is
(A) R
(B) R
(C) R2
(D) R2
Answer: Option D
98
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 D
99
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
100
Groynes are generally built
(A) Perpendicular to the bank
(B) Inclined up stream up to 30°
(C) Inclined downstream upto 30°
(D) All the above
Answer: Option B
101
Useful soil moisture for plant growth, is
(A) Capillary water
(B) Gravity water
(C) Hygroscopic water
(D) Chemical water
Answer: Option A
102
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
103
According to Kennedy, the critical velocity (V0) in metres 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).
(A) V0 = 0.84 mD0.64
(B) V0 = 0.55 mD0.64
(C) V0 = 0.84 mD0.54
(D) V0 = 0.55 mD0.54
Answer: Option B
104
For diversion of flood water of rivers, the type of canal constructed, is
(A) Ridge canal
(B) Perennial canal
(C) Inundation canal
(D) Canal
Answer: Option C
105
Lane's weighted creep theory assumes
(A) Equal weightage to horizontal and vertical creeps
(B) Double weightage to horizontal creep and one weightage to vertical creep
(C) Triple weightage to horizontal creep and one weightage to vertical creep
(D) Triple weightage to vertical creep and one weightage to horizontal creep
Answer: Option D
106
Solution of Laplacian equation in three dimensions d² /dx² + d² /dy² + d² /dz² = 0 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
107
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
Answer: Option D
108
A water-logged land is found suitable for cultivation due to
(A) Ease of tillage for preparation of the field for optimum condition of germination
(B) Absence of aeration of soil from root zone of the plant
(C) Regular supply of water to plants from the water table by capillary action
(D) None of these
Answer: Option D
109
Attracting groynes are built
(A) Perpendicular to the bank
(B) Inclined down stream
(C) Inclined up stream
(D) None of these
Answer: Option B
110
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
Answer: Option B
111
Which one of the following statements is correct?
(A) The canal system and the drainage system are complementary
(B) The canal system runs on ridges, gets divided into smaller channels and spreads its water on
the land
(C) The drainage system runs along the lowest line, collects drainage water from the slopes and
joins the main stream
(D) All the above
Answer: Option D
112
For cereal crops the most commonly adopted method of irrigation, is
(A) Free flowing method
(B) Check method
(C) Furrow method
(D) Sprinkling method
Answer: Option B
113
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
Answer: Option C
114
The intensity of irrigation means
(A) Percentage of culturable commanded area to be irrigated annually
(B) Percentage of gross commanded area to be irrigated annually
(C) Percentage of the mean of culturable commanded area and the gross commanded area to
be irrigated annually
(D) Total depth of water supplied by the number of waterings
Answer: Option A
115
Retrogression of the bed level of a river downstream a weir, occurs due to
(A) Heavy impact of water
(B) Increase of the bed level
(C) Less percentage of silt
(D) Soft soil strata
Answer: Option C
116
Meandering of a river generally occurs, in
(A) Rocky stage
(B) Delta stage
(C) Boulder stage
(D) Trough stage
Answer: Option D
117
For designing the venturi head,
(A) Width of the throat should not be less than one-third of the bed width of main canal
(B) Length of the throat should be 2.5 times the depth measured to F.S.L. in the main canal
(C) Minimum throat width should not be less than 60 cm
(D) All the above
Answer: Option D
118
Disposal of extra excavated earth of canals, is utilised to provide a spoil bank on
(A) Left side
(B) Right side
(C) Both sides
(D) All the above
Answer: Option D
119
In a concrete canal the approximate permissible velocity of water should not exceed
(A) 0.5 m/sec
(B) 1 m/sec
(C) 1.5 m/sec
(D) 2 m/sec
Answer: Option D
120
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
121
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
122
Pick up the incorrect statement from the following. Culturable commanded area is the gross area
of an irrigation canal system less
(A) Populated area
(B) Alkaline area
(C) Forest area
(D) Fallow land
Answer: Option D
123
The downstream 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
124
A fall which maintains its depth, is
(A) A trapezoidal notch fall
(B) A low weir fall
(C) A rectangular notch fall
(D) All the above
Answer: Option D
125
A current meter measures the velocity of flow, if it is held
(A) On the surface of water
(B) At the bottom of channel
(C) At any point within the cross-section
(D) None of these
Answer: Option C
126
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
127
When a canal is carried over a natural drainage, the structure provided, is known as
(A) Syphon
(B) Aqueduct
(C) Super passage
(D) Syphon-aqueduct
Answer: Option B
128
For smooth entry of water in a canal, the angle between head regulator and water is generally
kept
(A) 80°
(B) 90°
(C) 110°
(D) 120°
Answer: Option C
129
In rigid module, the discharge
(A) Is independent of water levels in the distributary and water course
(B) Depends upon the water level in distributary
(C) Depends upon the water level in the water course
(D) Depends upon the water levels of both, i.e. distributary and water course
Answer: Option A
130
For standing crops in undulating sandy fields, the best method of irrigation, is
(A) Sprinkler irrigation
(B) Free flooding
(C) Check method
(D) Furrow method
Answer: Option A
131
The saturation line is the line up to which banks get saturated after the canal runs for some time.
The saturation gradient in ordinary loam soil, is generally
(A) 2 : 1
(B) 3 : 1
(C) 4 : 1
(D) 5 : 1
Answer: Option C
132
Fundamental momentum equation for a hydraulic jump, is
(A) D - D q/g) × (V - V
(B) ² - ² = (2q/g) × (V - V
(C) D - D q/g) × ( - )
(D) D D q/g) × ( - )
Answer: Option B
133
The uplift pressure on the roof of an inverted syphon, is maximum when
(A) Drain in running dry
(B) Canal is running dry
(C) Canal is running with F.S.L.
(D) Drain is running with H.F.L.
Answer: Option D
134
The ratio of the discharge over a trapezoidal crest to a rectangular crest of Sarda falls of identical
parameters, is
(A) 1.084
(B) 1.074
(C) 1.064
(D) 1.054
Answer: Option A
135
B is the number of days of base period and D is the duty in
hectare/cumec, the relationship which holds good, is
(A) D D/B)
(B) B B/D)
(C) D B)
(D) = (8.6 B/D)
Answer: Option D
136
The top soil of a water logged field becomes more alkaline and infertile if its pH value is
(A) 5
(B) 7
(C) 9
(D) 11
Answer: Option D
137
If average particle size of the silt in millimetres is m, the Lacey's silt factor f is proportional to
(A) m3
(B) m1/2
(C) m1/3
(D) m2/3
Answer: Option B
138
The sensitivity of a rigid module, is
(A) 2.00
(B) 1.50
(C) 1.00
(D) Zero
Answer: Option D
