Irrigation Objective Type Questions and Answers

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

A consumptive irrigation requirement

B net irrigation requirement

C effective rainfall

D consumptive use

View Answer

Answer: consumptive irrigation requirement

22 With the increase in the quantity of water supplied, the yield of most crops

A increases upto a certain limit and then decreases

B increases upto a certain limit and then becomes constant

C increases continuously

D decreases continuously

View Answer

Answer: increases upto a certain limit and then decreases

23 If the intensity of rainfall is more than the infiltration capacity of soil, then the infiltration rate will be

A equal to infiltration capacity

B more than infiltration capacity

C more than rate of rainfall

D equal to rate of rainfall

View Answer

Answer: equal to infiltration capacity

24 Cyclonic precipitation is caused by lifting of an air mass due to

A natural topographical barriers

B temperature difference

C pressure difference

D all of the above

View Answer

Answer: pressure difference

25 A raingauge should preferably be fixed

A in an open space

B in a closed space

C under the tree

D near the building

View Answer

Answer: in an open space

26 The most suitable material for the central impervious core of a zoned embankment type dam is

A clay mixed with fine sand

B silty clay

C coarse sand

D clay

View Answer

Answer: clay mixed with fine sand

27 As compared to gravity dams, earthen dams

A require less skilled labour

B require sound rock foundations

C are costlier

D are less susceptible to failure

View Answer

Answer: require less skilled labour

28 For wave action in dams, the maximum height of freeboard is generally taken to be equal to

A 1.50 hw

B 1.25 hw

C 0.5 hw

D 0.75 hw

View Answer

Answer: 1.50 hw

29 The maximum permissible eccentricity for no tension at the base of a gravity dam is

A B/6

B B/4

C B/2

D B/3

View Answer

Answer: B/6

30 When the reservoir is full, the maximum compressive force in a gravity dam is produced

A within the middle third of base

B at centre of base

C at the toe

D at the heel

View Answer

Answer: at the toe

31 The major resisting force in a gravity dam is

A self-weight of dam

B uplift pressure

C wave pressure

D water pressure

View Answer

Answer: self-weight of dam

32 Hydrodynamic pressure due to earthquake acts at a height of

A 4H/371 above the base

B 4H737t below the water surface where H is the depth of water.

C 3H747t below the water surface

D 3H/47I above the base

View Answer

Answer: 4H/371 above the base

33 Horizontal acceleration due to earthquake results in

A inertia force into the body of the dam

B hydrodynamic pressure

C both (a) and (b)

D none of the above

View Answer

Answer: both (a) and (b)

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

A two-third of hydrostatic pressure at toe plus one-third of hydrostatic pressure at heel

B average of hydrostatic pressure at toe and heel

C hydrostatic pressure at toe

D none of the above

View Answer

Answer: two-third of hydrostatic pressure at toe plus one-third of hydrostatic pressure at heel

35 When the upstream face of a gravity dam is vertical, then the intensity of water pressure at the water surface and at the base respectively will be

A OandwII

B wH and 0

C 0 and wH212

D wH2/2and wH2/3

View Answer

Answer: OandwII

36 The total capacity of a reservoir is 25 million cubic metres and dead storage is 5 million cubic metres. If the average volume of sediment deposition is 0.10 million cubic metre per year, then the usefulness of the reservoir will start reducing after

A 250 years

B 50 years

C 200 years

D 150 years

View Answer