As the height of a proposed dam is increased, usually, the cost per unit of storage

Initially decreases and then increases

Initially increases and then decreases

Initially decreases and then increases

remains unaffected by the height

If the height of the hydraulic gradient line above the floor of thickness t is h and the specific gravity of the material of the floor is G, the minimum thickness t of the floor down stream of the crest wall, is given by the question-

\(t = \frac{{h - 1}}{{G + t}}\)

\(t = \frac{{h - 1}}{{G - t}}\)

According to Khosla’s, the exit gradient of surface flow

is independent of the b/d ratio

is independent of the depth of d/s cut-off walls

a dam constructed using stone masonry

all the forces due to water, wave, uplift, etc. are resisted by the weight of the dam

a dam constructed using stone masonry

a dam constructed using concrete

“Bank storage” in a dam reservoir

Sometimes decreases and sometimes increases the computed reservoir capacity

Decreases the computed reservoir capacity

Increases the computed reservoir capacity

Sometimes decreases and sometimes increases the computed reservoir capacity

Has no effect on reservoir capacity

Auxiliary devices in stilling basins are provided

To reduce the length of the basin

As additional measure to control jump

A filter is provided at the d/s toe of an earth dam

to prevent the piping action in the dam section

to reduce the seepage through the dam

to reduce the uplift pressure on the dam

to collect and drain out the seepage water

Economical height of a dam is that height, for which the

cost benefit ratio is minimum and net benefits are maximum

cost per unit storage is minimum

cost benefit ratio is minimum and net benefits are maximum

cost benefit ratio is maximum and net benefits are maximum

Bligh’s theory is associated with

Design of foundations on loose soil

Design of hydraulic structures on permeable strata

Match List 1 and List 2 and select the correct answer using the codes given below:List-1 List-2 A. Cut-off trench of a dam to be constructed across the flowing river 1. Cellular sheetpile cofferdam B. Shallow foundation of a bridge pier foundation work 2. Embankment type cofferdam C. Sequential repetition of underwater foundation work 3. Single wall sheetpile cofferdam D. Control of groundwater to prevent entry into a deep excavation 4. Floating steel cylinder cofferdam

A – 2, B – 3, C – 1, D - 4

A – 4, B – 3, C – 2, D - 1

A – 2, B – 1, C – 4, D - 3

A – 2, B – 3, C – 1, D - 4

A – 3, B – 4, C – 2, D - 1

It was found that the critical angle of a dam against seepage pressure with respect to normal was 45 degrees. According to Khosla creep theory, what can you say about the structure?

The dam is stable against lateral pressure

The dam is stable against seepage pressure

The dam is stable against overturning

The dam is stable against lateral pressure

The dam is stable against heave pressure

38 + Mcqs in Dams And Spillways in Irrigation Engineering Page 1 McqOptions

1.	_____ is the rigid dam that is constructed either with stone or brick masonry or mass concrete.
A.	Solid gravity dam
B.	Footing dam
C.	Buttress dam
D.	Sediment dam
Answer» B. Footing dam

Discussion

2.	As the height of a proposed dam is increased, usually, the cost per unit of storage
A.	Increases
B.	Decreases
C.	Initially increases and then decreases
D.	Initially decreases and then increases
E.	remains unaffected by the height
Answer» D. Initially decreases and then increases

Discussion

3.	In Gravity dam, the ______ acts in a direction opposite to the acceleration imparted by earthquake forces and is equal to the product of the mass and the acceleration
A.	Inertia force
B.	Hydrodynamic force
C.	Uplift force
D.	Wave pressure
Answer» B. Hydrodynamic force

Discussion

4.	If the height of the hydraulic gradient line above the floor of thickness t is h and the specific gravity of the material of the floor is G, the minimum thickness t of the floor down stream of the crest wall, is given by the question-
A.	\(t = \frac{{h }}{{G - 1}}\)
B.	\(t = \frac{{h + 1}}{{G}}\)
C.	\(t = \frac{{h - 1}}{{G + t}}\)
D.	\(t = \frac{{h - 1}}{{G - t}}\)
Answer» B. \(t = \frac{{h + 1}}{{G}}\)

Discussion

5.	In Gravity dam, the factor of safety against overturning should not be less than
A.	1.15
B.	1.5
C.	1.8
D.	2
Answer» C. 1.8

Discussion

6.	Consider the following statements related to uplift pressure in gravity dams:1. A drainage gallery reduces the uplift pressure at all levels below the gallery.2. A drainage gallery below upstream water level reduces the uplift pressure at all levels below the upstream water level.3. A grout curtain near the heel reduces seepage and uplift pressure everywhere on the gravity dam whatever the upstream water level.Which of the above statements are correct?
A.	2 and 3 only
B.	1 and 2 only
C.	1 and 3 only
D.	1, 2 and 3
Answer» B. 1 and 2 only

Discussion

7.	A new reservoir has a capacity of 12 Mm3 and its catchment area is 400 km2. The annual sediment yield from this catchment is 0.1 ha.m/km2 and the trap efficiency can be assumed constant at 90%. The number of years it takes for the reservoir to lose 50% of its initial capacity is, nearly
A.	177 years
B.	77 years
C.	17 years
D.	7 years
Answer» D. 7 years

Discussion

8.	In a ski-jump bucket provided in an overflow spillway, the lip angle is 30°, and the actual velocity of flow entering the bucket is 30 m/s. The maximum vertical height attained by the trajectory of the jet, measured above the lip of the bucket, is nearly
A.	45 m
B.	35 m
C.	22 m
D.	11 m
Answer» E.

Discussion

9.	Earthen dams are
A.	Rigid dams
B.	Non-rigid dams
C.	Reinforced with steel
D.	Overflow dams
E.	Diversion dams
Answer» C. Reinforced with steel

Discussion

10.	In case of non-availability of space due to topography, the most suitable spillway in this condition is ____
A.	Straight drop spillway
B.	Chute spillway
C.	Shaft spillway
D.	Ogee spillway
Answer» D. Ogee spillway

Discussion

11.	About _______ of the total storage of the reservoir is assumed to be the dead storage in a dam reservoir.
A.	10 - 12%
B.	20 - 25%
C.	25 - 35%
D.	0 - 5%
Answer» C. 25 - 35%

Discussion

12.	A dam of water depth of which produces a hydrostatic force F on the dam face. If the water depth doubles to 2 h, the hydrostatic force on the dam face will then be
A.	\(\frac{F}{2}\)
B.	F
C.	2F
D.	4F
Answer» E.

Discussion

13.	Leakage through the transverse joints in a gravity dam is prevented by
A.	Shear keys
B.	Key ways
C.	Water stops
D.	Proper instrumentation
E.	Joint sealants
Answer» D. Proper instrumentation

Discussion

14.	According to Khosla’s, the exit gradient of surface flow
A.	depends upon the b/d ratio
B.	is independent of the b/d ratio
C.	is independent of the depth of d/s cut-off walls
D.	None of the above
Answer» B. is independent of the b/d ratio

Discussion

15.	In Montague-type fall
A.	a straight glacis is provided
B.	a circular glacis is provided
C.	a parabolic glacis is provided
D.	No glacis is provided
Answer» D. No glacis is provided

Discussion

16.	A gravity dam means:
A.	a dam constructed using earth
B.	all the forces due to water, wave, uplift, etc. are resisted by the weight of the dam
C.	a dam constructed using stone masonry
D.	a dam constructed using concrete
Answer» C. a dam constructed using stone masonry

Discussion

17.	For safety of a concrete dam against overturning, what must be width of the dam of rectangular cross section of height 10 m, if the height of water storage on one side of it is 9 m? Take unit weight of water as 10 kN/m3 and unit weight of concrete as 25 kN/m3.(Ignore effect of uplift, friction and any other force)
A.	\(\dfrac{4\sqrt{3}}{5} \ m\)
B.	\(\dfrac{3\sqrt{3}}{5} \ m\)
C.	\(9\dfrac{\sqrt{3}}{5} \ m\)
D.	0.6 m
Answer» D. 0.6 m

Discussion

18.	In a______ dam, the external forces are resisted by the weight of the dam.
A.	gravity
B.	rigid
C.	arch
D.	earth
E.	buttress
Answer» B. rigid

Discussion

19.	On which river is the Krishna Raja Sagar Dam built?
A.	Tungabhadra
B.	Krishna
C.	Kali nadi
D.	Kaveri
Answer» E.

Discussion

20.	At the base of a gravity dam section, the vertical stress at the toe was found to be 2.4 MPa. If the downstream face of the dam has a slope of 0.707 horizontal : 1 vertical, and if there is no tail water, the maximum principal stress at the toe of the dam is
A.	1.7 MPa
B.	2.4 MPa
C.	3.6 MPa
D.	4.8 MPa
Answer» D. 4.8 MPa

Discussion

21.	For the upstream face of an earthen dam, the most adverse condition for stability of slope is:
A.	sudden drawdown
B.	steady seepage
C.	during construction
D.	sloughing of slope
Answer» B. steady seepage

Discussion

22.	Consider the following data regarding a theoretical profile of a dam:Permissible value of compressible stress σ = 350 tonnes/m2Specific gravity of concrete s = 2.4Uplift coefficient c = 0.6 mThe value of γ = 1The height and base width will be nearly
A.	125 m and 63 m
B.	175 m and 63 m
C.	125 m and 93 m
D.	175 m and 93 m
Answer» D. 175 m and 93 m

Discussion

23.	“Bank storage” in a dam reservoir
A.	Decreases the computed reservoir capacity
B.	Increases the computed reservoir capacity
C.	Sometimes decreases and sometimes increases the computed reservoir capacity
D.	Has no effect on reservoir capacity
Answer» C. Sometimes decreases and sometimes increases the computed reservoir capacity

Discussion

24.	Auxiliary devices in stilling basins are provided
A.	To stabilise the flow
B.	To reduce the length of the basin
C.	As additional measure to control jump
D.	All of the above
Answer» E.

Discussion

25.	Coordination between field and design engineers to ensure continuous field observations and modifications in design during construction, is more importantly required in case of
A.	concrete gravity dams
B.	Masonry dams
C.	arch dams
D.	rockfill dams
E.	earthen dams
Answer» F.

Discussion

26.	A filter is provided at the d/s toe of an earth dam
A.	to prevent the piping action in the dam section
B.	to reduce the seepage through the dam
C.	to reduce the uplift pressure on the dam
D.	to collect and drain out the seepage water
Answer» E.

Discussion

27.	Economical height of a dam is that height, for which the
A.	cost per unit storage is minimum
B.	cost benefit ratio is minimum and net benefits are maximum
C.	cost benefit ratio is maximum and net benefits are maximum
D.	net benefits are maximum
Answer» B. cost benefit ratio is minimum and net benefits are maximum

Discussion

28.	_______ is only suitable for small bunds or thin arch dams.
A.	Straight Drop Spillway
B.	Ogee Spillway
C.	Shaft Spillway
D.	Side Channel Spillway
Answer» B. Ogee Spillway

Discussion

29.	Bligh’s theory is associated with
A.	Design of RCC members
B.	Design of foundations on loose soil
C.	Design of hydraulic structures on permeable strata
D.	Design of on-shore structures
Answer» D. Design of on-shore structures

Discussion

30.	In 1 : 36 model of a spillway, the velocity is 2 m / s. What is the corresponding velocity in the prototype?
A.	36 m / s
B.	2 m / s
C.	12 m / s
D.	6 m / s
Answer» D. 6 m / s

Discussion

31.	Consider the following statements in respect of dams:1. In a gravity dam, a grout curtain is provided near the toe to reduce the exit gradient.2. A drainage gallery with its drainage pipe system provided in a gravity dam reduces the uplift pressure at all levels below the upstream water level.3. An earthquake acceleration of 0.1 g acting vertically downward causes a decrease of 10% in the limit weight of concrete and of water in a gravity dam.4. The Tehri dam is a gravity dam.Which of the above statements are correct?
A.	1 and 3 only
B.	1 and 4 only
C.	2 and 3 only
D.	2 and 4 only
Answer» B. 1 and 4 only

Discussion

32.	If L is effective length of spillway crest and H is the total head over the spillway crest including velocity head, the discharge passing over an Ogee spillway is given by
A.	CLH3/2
B.	CHL3/2
C.	CLH5/2
D.	CLH1/2
Answer» B. CHL3/2

Discussion

33.	Beaver dam is type of
A.	Earth dam
B.	Buttress dam
C.	Timber dam
D.	Steel dam
Answer» D. Steel dam

Discussion

34.	A masonry dam 8 m high, 1.5 m wide at the top and 5 m wide at the base retains water to a depth of 7.5 m, the water face of the dam being vertical. If the weight of water is 9.81 kN/m3, weight of masonry is 22 kN/m3,the maximum intensity of stress developed at the base will be nearly
A.	196 kN/m2
B.	182 kN/m2
C.	160 kN/m2
D.	148 kN/m2
Answer» C. 160 kN/m2

Discussion

35.	A _____ is a structure used to provide for the controlled release of flows from a dam or levee into a downstream area.
A.	weir
B.	sluice
C.	spillway
D.	approach
Answer» D. approach

Discussion

36.	Match List 1 and List 2 and select the correct answer using the codes given below:List-1 List-2 A. Cut-off trench of a dam to be constructed across the flowing river 1. Cellular sheetpile cofferdam B. Shallow foundation of a bridge pier foundation work 2. Embankment type cofferdam C. Sequential repetition of underwater foundation work 3. Single wall sheetpile cofferdam D. Control of groundwater to prevent entry into a deep excavation 4. Floating steel cylinder cofferdam
A.	A – 4, B – 3, C – 2, D - 1
B.	A – 2, B – 1, C – 4, D - 3
C.	A – 2, B – 3, C – 1, D - 4
D.	A – 3, B – 4, C – 2, D - 1
Answer» C. A – 2, B – 3, C – 1, D - 4

Discussion

37.	_________ is an example of a non – rigid dam
A.	Arch dam
B.	Timber dam
C.	Steel dam
D.	Rockfill dam
Answer» E.

Discussion

38.	It was found that the critical angle of a dam against seepage pressure with respect to normal was 45 degrees. According to Khosla creep theory, what can you say about the structure?
A.	The dam is stable against seepage pressure
B.	The dam is stable against overturning
C.	The dam is stable against lateral pressure
D.	The dam is stable against heave pressure
Answer» C. The dam is stable against lateral pressure

Discussion

Explore topic-wise MCQs in Irrigation Engineering.

_____ is the rigid dam that is constructed either with stone or brick masonry or mass concrete.

As the height of a proposed dam is increased, usually, the cost per unit of storage

In Gravity dam, the ______ acts in a direction opposite to the acceleration imparted by earthquake forces and is equal to the product of the mass and the acceleration

If the height of the hydraulic gradient line above the floor of thickness t is h and the specific gravity of the material of the floor is G, the minimum thickness t of the floor down stream of the crest wall, is given by the question-

In Gravity dam, the factor of safety against overturning should not be less than

A new reservoir has a capacity of 12 Mm3 and its catchment area is 400 km2. The annual sediment yield from this catchment is 0.1 ha.m/km2 and the trap efficiency can be assumed constant at 90%. The number of years it takes for the reservoir to lose 50% of its initial capacity is, nearly

In a ski-jump bucket provided in an overflow spillway, the lip angle is 30°, and the actual velocity of flow entering the bucket is 30 m/s. The maximum vertical height attained by the trajectory of the jet, measured above the lip of the bucket, is nearly

Earthen dams are

In case of non-availability of space due to topography, the most suitable spillway in this condition is ____

About _______ of the total storage of the reservoir is assumed to be the dead storage in a dam reservoir.

A dam of water depth of which produces a hydrostatic force F on the dam face. If the water depth doubles to 2 h, the hydrostatic force on the dam face will then be

Leakage through the transverse joints in a gravity dam is prevented by

According to Khosla’s, the exit gradient of surface flow

In Montague-type fall

A gravity dam means:

In a______ dam, the external forces are resisted by the weight of the dam.

On which river is the Krishna Raja Sagar Dam built?

At the base of a gravity dam section, the vertical stress at the toe was found to be 2.4 MPa. If the downstream face of the dam has a slope of 0.707 horizontal : 1 vertical, and if there is no tail water, the maximum principal stress at the toe of the dam is

For the upstream face of an earthen dam, the most adverse condition for stability of slope is:

Consider the following data regarding a theoretical profile of a dam:Permissible value of compressible stress σ = 350 tonnes/m2Specific gravity of concrete s = 2.4Uplift coefficient c = 0.6 mThe value of γ = 1The height and base width will be nearly

“Bank storage” in a dam reservoir

Auxiliary devices in stilling basins are provided

Coordination between field and design engineers to ensure continuous field observations and modifications in design during construction, is more importantly required in case of

A filter is provided at the d/s toe of an earth dam

Economical height of a dam is that height, for which the

_______ is only suitable for small bunds or thin arch dams.

Bligh’s theory is associated with

In 1 : 36 model of a spillway, the velocity is 2 m / s. What is the corresponding velocity in the prototype?

If L is effective length of spillway crest and H is the total head over the spillway crest including velocity head, the discharge passing over an Ogee spillway is given by

Beaver dam is type of

A masonry dam 8 m high, 1.5 m wide at the top and 5 m wide at the base retains water to a depth of 7.5 m, the water face of the dam being vertical. If the weight of water is 9.81 kN/m3, weight of masonry is 22 kN/m3,the maximum intensity of stress developed at the base will be nearly

A _____ is a structure used to provide for the controlled release of flows from a dam or levee into a downstream area.

_________ is an example of a non – rigid dam

It was found that the critical angle of a dam against seepage pressure with respect to normal was 45 degrees. According to Khosla creep theory, what can you say about the structure?