Irrigation Engineering

11. A river training work is generally required when the river is

1. Meandering
2. Aggrading
3. Degrading
4. All the above

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12. A water-logged land is found suitable for cultivation due to

1. Ease of tillage for preparation of the field for optimum condition of germination
2. Absence of aeration of soil from root zone of the plant
3. Regular supply of water to plants from the water table by capillary action
4. None of these

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

1. Straight path under the foundation of the dam
2. Circular path under the foundation of the dam
3. The outline of the base of the foundation of the dam
4. None of these

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14. According to G.W. Pickles the effect of confining the flood water of a river between levee, is to increase

1. Rate of flood wave
2. Water surface elevation during floods
3. Maximum discharge
4. Surface slope of streams above the levied portion

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15. 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).

1. V₀ = 0.84 mD^0.64
2. V₀ = 0.55 mD^0.64
3. V₀ = 0.84 mD^0.54
4. V₀ = 0.55 mD^0.54

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16. According to Khosla, the exits gradient of surface flow

1. Depends upon the b/d ratio
2. Is independent of the b/d ratio
3. Is independent of the depths of d/s cut off walls
4. None of these

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17. According to Lacey, depth of scour in a river depends upon the straightness of the reach. If D is the depth of scour in regime flow in a right angled bend, it is

1. 1.25 D
2. 1.50 D
3. 1.75 D
4. 2.00 D

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18. According to Lacey, in regime conditions

1. Silt is kept in suspension by vertical components of eddies
2. Entire cross-section of the channel is generated at all points by the forces normal to the wetted perimeter
3. Both (a) and (b)
4. Neither (a) nor (b)

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19. An outlet is said to be proportional if its flexibility, is

1. Zero
2. Less than one
3. More than one
4. One

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

1. Non-modular outlet
2. Semi-modular outlet
3. Flexible modular outlet
4. Right modular outlet

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