Irrigation Engineering objective question and answer

Irrigation Engineering objective question and answer part 2

Question No. 101

Useful soil moisture for plant growth, is 

(A) Capillary water 

(B) Gravity water 

(C) Hygroscopic water 

(D) Chemical water 

Answer: Option A 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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

Question No. 116

Meandering of a river generally occurs, in 

(A) Rocky stage 

(B) Delta stage 

(C) Boulder stage 

(D) Trough stage 

Answer: Option D 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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 

Question No. 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

Question No. 132

Fundamental momentum equation for a hydraulic jump is 

A. D₁² - D₂² = (2q/g) × (V₁ - V₂) 

B. D₂² - D₁² = (2q/g) × (V - V₂) 

C. D₁² - D₂² = (2q/g) × (V₂ - V₁) 

D. D₁² + D₂² = (2q/g) × (V₂ - V₁)

Answer: Option B 

Question No. 13

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 

Question No. 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 

Question No. 135

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 

A. D = Δ (8.64 D/B) 

B. B = Δ (8.64 B/D) 

C. D = (8.6 Δ/B) 

D. Δ = (8.6 B/D)

Answer: Option D 

Question No. 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

Question No. 137

If average particle size of the silt in millimetres is m, the Lacey's silt factor f is proportional to 

(A) m

3

(B) m

1/2

(C) m

1/3

(D) m

2/3

Answer: Option B 

Question No. 138

The sensitivity of a rigid module, is 

(A) 2.00 

(B) 1.50 

(C) 1.00 

(D) Zero 

Answer: Option D